Field of Invention

This invention relates to orthodontic appliances and, in particular, to an orthodontic appliance involving the combined use of a dental aligner and a dental attachment.

Description of Related Art

Dental aligners are used to straighten teeth as an alternative to dental braces. Aligners are typically formed as removable plastic trays that are customized to a patient’s dental arch. The aligner provides a geometry selected to reposition the teeth from one tooth arrangement to the next arrangement. There are discrepancies between the aligner and the teeth, and the force generated by these discrepancies reposition the teeth to the next arrangement. However, a counterforce to the aligner may also lead to minor displacement of the aligner from its fully installed position in the dental arch.

A dental attachment is an object that is attached directly to the surface of a tooth of the patient. Dental attachments were introduced into dental treatment to improve the treatment result. The term “aligner system” refers to the combined use of one aligner and one or more dental attachments on the same dental arch of the patient. After more than 15 years of clinical use and improvement of aligner systems, there are still many problems in the treatment of difficult orthodontic cases.

Tooth tipping and minor dislocation of aligners often happen. The conventional aligner system, which consists of the aligner and the attachments, cannot prevent gradual unintentional dislocation of the aligner. Incomplete insertion may also result in aligner dislocation.

United States Patent application publication No. 2019/0274788 to Cetta et al. discloses orthodontic elastic attachments that are customized to fit with the cutout of the aligner with a gingival side opening. The base pad has a shape that complements the shape of the plastic window such that it fits within the aligner’s cut-out like a puzzle piece. So, the base pad has contact with the cutout edge, but the aligner system of Cetta et al. does not have features to prevent the aligner from dislocation, and no force engagement between the aligner and the attachment is mentioned.

United States Patent application publication No. 2004/0048223 to Phan et al. discloses an aligner system wherein the aligner slides over the attachments to fit into the designated place; and the aligner slides over the attachments again when the aligner is removed from the dental arch. This sliding over mechanism cannot prevent minor dislocation if the dislocation force is very big, and the retention force generated by the engagement between the attachment and the aligner is not big enough to hold the aligner in place. This aligner system of Phan et al. cannot prevent gradual displacement from the fully installed position.

Some improvement needs to be made to solve these problems.

SUMMARY OF THE INVENTION

To prevent minor displacement of the aligner from its fully installed position on the dental arch and other problems with conventional aligner systems, the present invention provides novel orthodontic apparatus and methods of manufacturing.

One general aspect includes an orthodontic appliance for repositioning teeth. The orthodontic appliance also includes (a)an aligner having a thickness and may include a cutout located at a tooth surface of the teeth when the aligner is installed, and the cutout having an opening dimensioned for being oriented towards a gingival edge of the aligner; and (b)an attachment dimensioned for being attached to the tooth surface of the teeth where the cutout is aligned, the attachment having an attachment body and a base, the base being connected to the tooth surface, the attachment body projecting away from the tooth, where the height of the attachment body is longer than the thickness of the aligner at the cutout edge. The appliance also includes where a part of the aligner is at the gingival side of at least part of the attachment body and contacts the attachment body when the aligner is in its fully installed position, the side surface of the attachment body being dimensioned to inhibit the part of the aligner from sliding over the top surface of the attachment body when the aligner is being displaced from its fully installed position, the part of the aligner and the attachment body being dimensioned to resiliently engage with each other to hinder displacement of the aligner from its fully installed position.

Implementations may include one or more of the following features. The orthodontic appliance where the attachment may include a wing separated from the base, a slot being formed between the wing and one of the base and the tooth surface, the slot being formed between the wing and the tooth surface when the base does not extend laterally beyond the attachment body, the slot having an opening whose width is greater than the thickness of the aligner at the cutout edge. At least part of the side surface of the attachment body forms one of an acute and a right angle with the tooth surface. The height of the attachment body is at least 1.4 times the thickness of the aligner at the cutout edge. At least part of the aligner next to the cutout is spaced away from the tooth surface such that an unoccupied space feature is formed next to the cutout between the aligner and one of a) the attachment base and b) the tooth surface. An inner surface of the aligner is engaged with the attachment body when the aligner is fully installed. An outer surface of the aligner is engaged with the attachment body when the aligner is fully installed.

One general aspect includes an orthodontic appliance for repositioning teeth. The orthodontic appliance also includes an aligner having cavities arranged to receive the teeth, the teeth may include one repositionable tooth arranged to be repositioned by the aligner; where part of the aligner is spaced away from a surface of the teeth, such that at least one aligner bulge over an unoccupied space feature is formed at one or more teeth next to the one repositionable tooth when the aligner is fully installed.

Implementations may include one or more of the following features. The orthodontic appliance may include an attachment for being cemented on a tooth next to the one repositionable tooth and where the aligner bulge is formed over the attachment, and where the aligner has no contact with the attachment. The aligner bulge is formed next to the attachment, and where the aligner only has contact with a top surface of the attachment.

The aligner bulge covers a surface of the one or more tooth such that the aligner has no contact with the surface of that tooth. The aligner bulge covers part of a surface of the one or more tooth. The aligner is designed to contact only a prominent part of a surface of the one or more tooth.

One general aspect includes an orthodontic appliance for repositioning teeth. The orthodontic appliance also includes an upper aligner dimensioned for installation on the upper dental arch and a lower aligner dimensioned for installation on the lower dental arch, where at least one of the lower aligner and the upper aligner is spaced away from part of an occlusal surface of the teeth, such that four or more aligner bulges over an unoccupied space features are formed when the aligners are fully installed.

Implementations may include one or more of the following features. The orthodontic appliance where each said aligner bulges covers only part of an occlusal surface of one tooth of the teeth. An occlusal surface of the lower aligner over at least one of lower premolars and lower canines of the teeth permits contact with the upper aligner when the aligners are fully installed.

One general aspect includes an orthodontic appliance for repositioning teeth. The orthodontic appliance also includes an upper aligner dimensioned for installation on the upper dental arch and a lower aligner dimensioned for installation on the lower dental arch, where an occlusal surface of the lower aligner over at least one of the lower premolars and lower canines of the teeth permits contact with the upper aligner when the aligners are fully installed.

Implementations may include one or more of the following features. The orthodontic appliance where a part of at least one of the lower aligner and the upper aligner at a location covering an occlusal surface of at least one of the premolars and canines of the teeth is thicker than other parts of that aligner.

One general aspect includes an orthodontic appliance for repositioning teeth. The orthodontic appliance also includes an upper aligner dimensioned for installation on the upper dental arch and a lower aligner dimensioned for installation on the lower dental arch, where at least one of the lower aligner and the upper aligner is spaced away from part of a surface of the teeth such that one or more unoccupied space features is formed between that aligner and an incisor edge of anterior teeth when the aligners are fully installed.

Implementations may include one or more of the following features. The orthodontic appliance where an incisal edge of the lower aligner permits contact with the upper aligner when the aligners are fully installed.

One general aspect includes an orthodontic appliance for repositioning teeth. The orthodontic appliance also includes an upper aligner dimensioned for installation on the upper dental arch and a lower aligner dimensioned for installation on the lower dental arch, where an incisal edge of the lower aligner permits contact with the upper aligner when the aligners are fully installed, and where part of the lower aligner at a location around an incisor edge of the lower anterior teeth is thicker than other parts of the lower aligner.

The teeth generally refer to all natural and non-natural teeth in a patient's dentition.

The attachment is bonded to and/or formed over a dental feature in a desired location. The attachment may be bonded to any of these teeth with any suitable bonding material, typically dental restorative composites.

The attachments may be constructed from a variety of materials, including but not limited to metals, glass, porcelain or silicone filled polymers, and other composite materials. Such materials are typically designed to be chip, break and shear resistant for durability. The base of the attachment may be constructed from the same or from different materials as the attachment body. Likewise, the attachment body may be permanently or removably mounted on the base or the body and base may be constructed as one entity.

The attachment may also include or function as a hook for traction in some situations. This attachment can be used in the intramaxillary traction or intermaxillary traction. One general aspect includes a method of manufacturing an aligner for repositioning teeth having at least one cutout which has an opening toward a gingival edge of the aligner when the aligner is fully installed. The method also includes (a)providing a positive model of a dentition having model teeth and model gingiva next to the model teeth, and providing at least one added structure on a tooth surface of the model; (b)forming the aligner over the positive model and over the added structure such that the aligner includes a protrusion at the added structure location, and (c)cutting across the protrusion to form the cutout having a cutout edge raised away from a tooth surface of the teeth when the aligner is fully installed.

Implementations may include one or more of the following features. The method where the added structure extends to a gingival side of the model of the dentition, so that the cutout has an opening toward the gingival edge of the aligner when the aligner is fully installed. The protrusion may include at least one sidewall extending at an angle of more than 60 degrees relative to a part of the teeth surface of the model under the protrusion when the aligner is seated on the model. The protrusion has a base which extends laterally beyond a distal part above the base, and where the step of cutting is across the distal part. The method may include cementing an attachment to the teeth and installing the aligner onto the teeth by resiliently engaging the attachment into the cutout.

The foregoing summary is illustrative only and is not intended to be in any way limiting. Other aspects and features of the present invention will become apparent to those of ordinary skill in the art upon review of the following description of embodiments of the invention in conjunction with the accompanying figures and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate by way of example only embodiments of the invention: Figure 1 is a perspective view of the orthodontic appliance according to a first embodiment of the invention, showing an aligner having a cutout and an attachment attached to a tooth of a patient;

Figure 2 is a close-up perspective view of a portion of the orthodontic appliance shown in Figure 1 ;

Figure 3 is a close-up perspective view of the portion shown in Figure 2, showing initial contact between the aligner and attachment;

Figure 4 is a close-up perspective view of the portion shown in Figures 2 and 3, showing the aligner fully installed and engaging the attachment; Figure 5 is a top view of the attachment of Figure 4 and the cutout of the aligner when it is fully installed, showing contact between the attachment and a projection of the aligner;

Figure 6 is a top view of the attachment and the cutout of the aligner shown in Figure

5, showing the attachment in a second, different position; Figure 7 is a top view of the attachment and the cutout of the aligner shown in Figures

5 and 6, showing the attachment in a third position; Figure 8 is a top view of the cutout of the aligner shown in Figures 5 to 7, showing an alternative attachment having a different position and size; Figure 9 is a top view of the cutout of the aligner shown in Figures 5 to 8, showing a third attachment having an elliptical shape; Figure 10 is a top view of the cutout of the aligner shown in Figures 5 to 9, showing a fourth attachment having a triangular shape and showing, by dotted line, the aligner displaced from its fully installed position;

Figure 11 is a top view of the cutout of the aligner shown in Figures 5 to 10, showing the cutout and attachment having complementary shapes; Figure 12 is a side sectional view of the portion of the appliance shown in Figures 4 and

5, showing an attachment body of the attachment contacting a first portion of the aligner projection and not showing other portions of the aligner;

Figure 13 is a side sectional view of the portion shown in Figure 12, showing a variation of the attachment having a short attachment body; Figure 14 is a side sectional view of the portion shown in Figures 12 and 13, showing a varied attachment body whose side surface forms an acute angle with a tooth surface;

Figure 15 is a side sectional view of the portion shown in Figures 12 to 14, showing a varied attachment body whose side surface forms an obtuse angle with the tooth surface;

Figure 16 is a side sectional view of the portion shown in Figures 12 to 15, showing the attachment having a base that extends laterally beyond the attachment body; Figure 17 is a side sectional view of the portion shown in Figure 16, showing the attachment having a beveled base; Figure 18 is a side sectional view of the portion shown in Figures 16 and 17, showing the attachment and its base having smoothly rounded edges;

Figure 19 is a perspective view of a variation of the attachment shown in Figures 1 to 18, showing the attachment having a wing; Figure 20 is a perspective view of a further variation of the attachment shown in Figure 19, showing an elliptical wing;

Figure 21 is a side sectional view of the portion shown in Figures 12 to 18, showing the variation of the attachment having a wing; Figure 22 is a side sectional view of the portion shown in Figure 21 , showing a variation of the attachment having the wing and the beveled base; Figure 23 is a side sectional view of the portion shown in Figures 21 and 22, showing a variation of the attachment having a single-sided wing; Figure 24 is a side sectional view of the portion shown in Figure 23, showing a variation of the attachment having a slot of inwardly decreasing width; Figure 25 is a close-up perspective view of a portion of the appliance according to a second embodiment of the invention, showing a cutout having a pair of opposing projections and the attachment having a circular base and a circular wing;

Figure 26 is a perspective view of the portion shown in Figure 25, showing initial contact between the aligner and the attachment; Figure 27 is a perspective view of the portion shown in Figures 25 and 26, showing the aligner fully installed and engaging the attachment; Figure 28 is a top view of the cutout of the aligner and the attachment of Figure 27, shown for clarity without the base and the wing, showing the aligner in its fully installed position;

Figure 29 is a top view of the cutout of the aligner shown in Figure 28, showing a variation of the attachment body having a parallelogram-shaped cross- section;

Figure 30 is a top view of the cutout of the aligner shown in Figures 28 and 29, showing a further variation of the attachment body having a bullet-shaped cross- section;

Figure 31 is a top view of a variation of the portion of the appliance shown in Figures 28 to 30, showing a diamond-shaped cutout; Figure 32 is a top view of a portion of the appliance according to a third embodiment of the invention, showing a secondary cutout and a window dimensioned to not engage with any attachment;

Figure 33 is a top view of a portion of the appliance shown for clarity without the base and the wing according to a fourth embodiment of the invention;

Figure 34 is a top view of the portion shown in Figure 33, showing the attachment body in a second, different position; Figure 35 is a top view of the portion shown in Figure 33, showing the attachment body in a third, different position;

Figure 36 is a top view of a portion of the appliance according to a fifth embodiment of the invention, showing a pair of opposing projections in contact with each other at their respective projection tips;

Figure 37 is a top view of a portion of the appliance according to a sixth embodiment of the invention, showing the projection tip contacting the aligner at the opposite side of the opening;

Figure 38 is a side sectional view of a portion of a dental arch with an aligner fully installed according to a seventh embodiment of the invention, showing an aligner bulge next to a cutout engaged with an attachment body;

Figure 39 is a side sectional view of the portion shown in Figure 12 to18, showing a variation having an inner surface of a part of an aligner engaged with an attachment body when the aligner is fully installed;

Figure 40 is a side sectional view of the portion shown in Figure 39, showing a variation having an aligner bulge arranged next to the attachment when the aligner is fully installed;

Figure 41 is a side sectional view of the portion shown in Figure 40, showing a variation having an outer surface of a part of an aligner engaged with an attachment body when the aligner is fully installed;

Figure 42a is a horizontal sectional view of part of a dental arch with an aligner fully installed according to an eighth embodiment, showing an aligner bulge formed next to a cutout, and showing an aligner bulge formed at a tooth next to a repositionable tooth;

Figure 42b is a vertical sectional view of the same part of the dental arch shown in Figure 42a; Figure 43a is a horizontal sectional view of part of a dental arch with an aligner fully installed according to a nineth embodiment, showing an aligner bulge formed over a tooth next to a repositionable tooth, and showing the aligner bulge formed over a traditional attachment;

Figure 43b is a vertical sectional view of the same part of the dental arch shown in Figure 43a;

Figure 44a is a horizontal sectional view of part of a dental arch with an aligner fully installed according to a tenth embodiment, showing an aligner bulge formed over a tooth next to a repositionable tooth; Figure 44b is a vertical sectional view of the same part of the dental arch shown in Figure 44a;

Figure 45 is a vertical sectional view of part of a dentition, showing a wedge space between the occlusal surfaces of the upper and lower dental arches, and showing only the lower aligner occlusal surface over the last molar permitting contact with the upper aligner;

Figure 46a is a vertical sectional view of part of a dentition according to an eleventh embodiment, showing the lower aligner occlusal surface over the lower premolars and the canine permitting contact with the upper aligner when aligner bulges are applied;

Figure 46b is a vertical sectional view of part of a dentition according to an eleventh embodiment, showing a variation of the embodiment;

Figure 47 is a vertical sectional view of part of a dentition according to a twelfth embodiment, showing the lower aligner occlusal surface over the molars, premolars and the canines permitting contact with the upper aligner when aligner bulges are provided;

Figure 48a is a vertical sectional view of the incisors of a dentition according to a thirteenth embodiment, showing an incisor edge of the lower aligner permitting contact with the upper aligner when an aligner bulge is applied around the incisor edges;

Figure 48b is a vertical sectional view of the incisors of a dentition according to a thirteenth embodiment, showing a variation of the embodiment;

Figure 49 is a side sectional view of an aligner protrusion formed over an added structure on a tooth surface of a model of a dentition, showing manufacturing using an added structure and an aligner protrusion;

Figure 50 is a side sectional view of the aligner protrusion shown in Figure 49 when the aligner is fully installed on the tooth of the model of the dentition without the added structure, showing the aligner protrusion and a cross section line 98;

Figure 51 is a side sectional view of the aligner protrusion shown in Figure 50, showing a cutout formed at the cross-section of the aligner protrusion on a tooth surface of a patient;

Figure 52 is a side sectional view of an attachment cemented in the cutout on the tooth surface of the patient and engaging with the aligner;

Figure 53 is a side sectional view of another aligner protrusion when the aligner is fully installed on the model of the dentition, showing the aligner protrusion and a cross-section line 98; and Figure 54 is a side sectional view of the aligner protrusion shown in Figure 53 with a cutout formed at the cross-section of the aligner protrusion.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to Figure 1 , the orthodontic appliance is an apparatus according to a first embodiment of the invention that is shown generally at the appliance 10. The appliance 10 functions to reposition one or more teeth 12 of a dental arch 14 of a dental patient. In Figure 1 , the dental arch 14 and its teeth 12 are shown by dotted line. The appliance 10 involves the combination of an aligner 16 and an attachment 18 dimensioned for being attached, such as by adhesive bonding, to a given tooth 12, the aligner 16 having cavities dimensioned to receive the teeth. A repositionable tooth refers to a tooth which is arranged to be repositioned to correct alignment and spacing.

While Figure 1 shows one attachment 18 attached to one tooth 12, in general any number of attachments 18 attached to any number of teeth 12 of an upper and/or lower dental arch 14 may be employed to achieve a desired dental result.

Referring to Figure 1 to 4, the aligner 16 has a thickness and comprises a cutout 24 for being located at a tooth surface of a tooth when the aligner is fully installed 34, which cutout 24 has an opening at a gingival edge 17 of the alignerl 6. The aligner 16 may comprise more than one cutout 24, and each one of the cutouts 24 may have an associated attachment 18. The alignerl 6 next to the one cutout 24 and the associated attachment18 are dimensioned to engage with each other to hinder displacement of the alignerl 6 from its fully installed position 34. The attachment 18 is dimensioned for being attached to the tooth surface where the cutout 24 is aligned. The attachment 18 has an attachment body 44 and a base, the base is connected to the tooth surface, the attachment body 44 projects away from the tooth 12. The height of the attachment body 44 is greater than the thickness of the aligner 16 at a cutout edge26 of the cutout 24. In Figure 1 , the cutout and attachment are arranged on a buccal surface of the tooth. The cutout 24 and the attachment 18 may also be arranged on a lingual surface of a tooth12.

Referring to Figures 1 to 4, the aligner 16 is typically made of a resilient material custom-fitted to the shapes of the teeth 12 of the dental arch 14. The aligner 16 typically includes inward facing ridges 20 associated with the natural indentations 22 between adjacent pairs of teeth 12. A given ridge 20 typically is selected to conform to its associated indentation 22 for a natural fit of the aligner 16 to the dental arch 14 resulting in the insertion route 32 of the aligner being determined. The insertion and removal of the aligner 16 typically follows the same route 32. Formed within the aligner 16 is a cutout 24 that defines a cutout edge 26. In the embodiments of Figures 1 to 4, the cutout 24 has an opening at a gingival edge17 of the aligner 16 to permit removable installation of the aligner 16 onto the dental arch 14 of the patient, the cutout 24 is at the buccal surface of a tooth and has an opening toward gingiva when the aligner 16 is in its fully installed position 34. The cutout 24and the attachment 18 also can be arranged at the lingual surface of a tooth in some situations.

The aligner 16 along its cutout edge 26 defines a projection 28 that projects inwardly into the cutout 24. Because the insertion and removal of the aligner 16 follows the insertion route 32, the projection 28 of the aligner 16 also typically follows the insertion route 32 during insertion or removal of the aligner 16. The projection 28 is dimensioned to resiliently engage the attachment 18 during installation of the aligner 16 (Figures 3 and 4) such that the projection 28 hinders dislocation of the aligner 16 after the aligner 16 has been installed. In the exemplary embodiments of Figures 1 to 4, the projection 28 has a smoothly rounded tip 30 for ease of installation of the aligner 16.

Referring to Figures 2, 3 and 4, the projection 28 contacts the attachment 18 when it follows the insertion route 32 to insert the aligner 16 into the fully installed position 34. The projection 28 is squeezed by the attachment 18 during the aligner insertion. The attachment 18 directs a compressive force on the projection 28 during installation of the aligner 16.

From a point of initial contact (Figure 3), such compressive force increases as the aligner 16 is moved toward its fully installed position 34 (Figure 4). Midway between initial contact and the fully installed position 34, a point of maximum compressive force is reached. Thereafter, the compressive force becomes reduced and has a vertical component force toward the gingiva side (Figure 10) as the aligner 16 is moved into its fully installed position 34. Thus, the resilient engagement of the projection 28 against the attachment 18 advantageously prevents incomplete installation of the aligner 16 by urging the aligner 16 toward its fully installed position 34 after having reached its midway point of maximum compressive force.

As indicated in Figures 3 and 4, the aligner 16 is typically transparent or clear such that the teeth 12 are visible beneath the aligner 16. In variations, the projection 28 can project inwardly toward the interior of the cutout 24 from anywhere along the cutout edge 26, and in general any number of projections 28 may be employed. Usually a cutout 24 is located on the buccal and/or the lingual surface of the teeth when the aligner is installed, and the cutout 24 has an opening dimensioned for being oriented towards the gingiva. The projection 28 of the aligner 16 projects from the mesial side and/or the distal side of the cutout 24 toward the interior of the cutout 24.

Referring to Figure 5 in top view, the aligner 16 in its fully installed position 34 places the projection 28 in contact with the attachment 18. A part of the aligner 16 is at the gingival side of the attachment body 44 and contacts the attachment body 44 when the aligner 16 is in its fully installed position 34. The cutout edge 26 is resiliently engaged with the attachment body 44 to hinder displacement of the alignerl 6 from its fully installed position34. A side sectional view is made along line 11-11 which passes through the contact point 36 between the part of the aligner 16 and the attachment body44.

Referring to Figures 2 to 5, in the embodiment a situation analogous to insertion happens during dislocation of the aligner 16 because the removal also follows the same route 32. The projection 28 contacts the attachment 18 at the contact point 36 when the aligner is in its fully installed position 34, such that the attachment 18 may deliver a retention force to the aligner 16 through the projection 28. In most cases the dental arch 14 may also deliver a dislocation force to the aligner 16. If there is a dislocation force on the aligner 16, the projection 28 and the attachment 18 are dimensioned and positioned to resiliently engage with each other to counteract the dislocation force to maintain the aligner 16 in the fully installed position 34.

Referring to Figures 5 to 7, the attachment 18 may in general contact the cutout edge 26 at any contact point 36 thereof when the aligner 16 (a portion only of which is seen in Figures 5 to 7) is in its fully installed position 34. Such fully installed position 34 of the aligner 16 provides in some embodiments a persistent force by the aligner 16 at the contact point 36 to the given tooth 12 via the attachment 18. Such persistent force persists for the duration of time that the aligner 16 remains in its installed position, and typically acts to reposition the given tooth 12 in a desired direction. The attachment 18 need only contact a portion of the cutout edge 26 when the aligner 16 is in its fully installed position 34 for such persistent force to act as a repositioning force.

Referring to Figures 8 to 10, the attachment 18 may have any desired shape and size to produce the persistent repositioning force in any desired direction at any number of different contact points 36 along the cutout edge 26. In some embodiments, the aligner 16 in its fully installed position 34 extends partly over the gingiva of the patient.

Referring to Figure 10, the attachment body 44 has a protrusion 64 which projects in the opposite direction of the projection 28, and the attachment body protrusion 64 has a protrusion tip 68. During insertion of the aligner 16 the attachment body 44 deliver a compressive force on the projection 28. From a point of initial contact (Figure 3), such compressive force increases as the aligner is moved toward its fully installed position 34 (Figure 4). The projection 28 reaches the biggest deformation at the point of contact between the projection tip 30 and the protrusion tip 68, and at this point the attachment body 44 delivers maximum compressive force to the projection 28. Thereafter, the compressive force 72 becomes reduced and has a vertical component force74 toward the gingiva as the aligner 16 is moving into its fully installed position 34. Thus, the resilient engagement of the projection 28 against the attachment body 44 advantageously prevents incomplete installation of the aligner 16 by urging the aligner 16 toward its fully installed position 34 after having reached its midway point of maximum compressive force.

The minor displacement of the aligner 16 from its fully installed position 34 to a displaced position 38 causes compression of the resilient material of the projection 28, thereby urging the aligner 16 to return toward its fully installed position 34; the attachment body 44 delivers a compressive force 72 to the projection 28, and this compressive force 72 defines not only a horizontal component force 76, but also a vertical component force 74 that directs toward the gingiva and guides the aligner 16 to return to its fully installed position 34.

Referring to Figure 11 in top view, the attachment body 44 has a shape and size that is harmonious (i.e. coincides) with the cutout 24, and the attachment body 44 has contact with most of the inner edge 40 of the cutout at the fully installed position 34, displacement of the aligner 16 may trigger compressive force 72 (Figure 10) which may urge the aligner 16 toward its fully installed position 34.

Referring to Figures 5 to 11 , the projection 28 and the attachment 18 are dimensioned to resiliently engage with each other to hinder displacement of the alignerl 6 from its fully installed position34, the tip30 of the projection28 of the aligner 16 is at the gingival side of at least part of the attachment body44 when the alignerl 6 is in its fully installed position34 and the projection28 contacts the attachment body44. The projection tip 30 is smoothly rounded. In these embodiments the attachment body44 contacts only a portion of the cutout edge26 when the aligner16 is inserted into the fully installed position 34. The cutout edge 26 is resiliently engaged with the attachment body 44 to hinder displacement of the aligner 16 from its fully installed position 34. All these features shown in these figures may be applied in any embodiment about the cutout and attachment and combined with other features of the embodiment.

Figures 12 is a side view along lines 11-11 of Figure 5, Figure 13 to 18 are variations of the embodiment showed in Figure 12, these Figures only show the side view of a portion of the aligner 16 and the attachment 18 and for ease of illustration do not show the other parts of aligner 16. This portion of the aligner 16 is at the gingival side of the attachment body 44 and contacts the attachment body 44 at a contact point 36 when the aligner is in its fully installed position 34( referring to Figures 5). The attachment 18 includes its attachment body 44 projecting vertically away from its base 46 that is adjacent to the tooth surface 13. In the exemplary embodiments of Figures 12 and 13, the base 46 has the same width as the attachment body 44. In the exemplary embodiments of Figures 12 to 15, the aligner 16 in its fully installed position 34 contacts the attachment body 44 at the contact point 36. Usually the projection 28 of the alignerl 6 has more than one contact point 36 with the attachment body44.

Referring to Figure 12 and 13, the side surface 60 of attachment body 44 forms an angle 78 with the tooth surface 13 that is a right angle 78.

Referring to Figure 13, the attachment body 44 in its direction of projection may have any suitable length. Typically, the height of the attachment body 44 is greater than the thickness of the aligner 16 at the cutout edge to inhibit the projection 28 (referring to Figures 5 to 11) from sliding over the top surface 62 of the attachment body 44 and potentially displacing the aligner 16. Referring to Figures 12 to 18, the attachment body 44 in some embodiments is at least 1.4 times as long as the thickness of the aligner 16 at the cutout edge 26.

Referring to Figure 14, the side surface 60 of the attachment body 44 forms the angle 78 with the tooth surface 13 which in this embodiment is an acute angle 78. In this embodiment the height of the attachment body 44 is greater than the thickness of the aligner 16. In this embodiment the attachment body 44 inhibits the projection 28 from sliding over the top surface 62 of the attachment body 44 when the aligner 16 is displaced from its fully installed position34.

Referring to Figure 15, the side surface 60 of the attachment body 44 forms the angle 78 with the tooth surface 13 which in this embodiment is an obtuse angle 78, this angle is smaller than 130 degrees. In this embodiment the length of the attachment body 44 is typically made sufficient to prevent the projection 28 (Figure 6 et al.) sliding over the top surface 62 of the attachment body 44. The attachment body 44 in some embodiments is at least 1.8 times as long as the thickness of the aligner 16 at the cutout edge 26.

Referring to Figures 16 to 18, the base 46 in some embodiments extends from the attachment body44 adjacently to the given tooth surface 13 to advantageously define a larger surface area for attaching the attachment 18 to the given tooth 12. In variations, the base 46 can be attached to the attachment body 44 in any suitable manner, including being integrally attached as shown in Figures 16 to 18. In contrast to the embodiments of Figures 12 to 15, the exemplary embodiments of Figures 16 to 18 show the surface area of the base 46 being greater than the cross-sectional area of the attachment body 44.

The base 46 may have any suitable shape, including circular, elliptical, polygonal, or irregular for example. The base 46 in some embodiments is beveled, such as by being sloped downwardly as viewed in Figure 17 or having a smoothly rounded bevel 50 as shown in Figure 18 for example.

The base 46 and the attachment body 44 in some embodiments have orthogonal surfaces, as shown in Figure 16 for example. Additionally or alternatively, the base 46 and/or the attachment body 44 may have smoothly rounded edges, as shown in Figure 18 for example. In the exemplary embodiment shown in Figure 18, the attachment body 44 widens in the direction projecting away from the given tooth 12, thereby assisting in preventing the aligner 16 from sliding overtop surface 62 of the attachment body 44.

Referring to Figure 18, part of the side surface 60 of the attachment body 44 forms the angle 78 with the tooth surface 13 which in this embodiment is an acute angle 78. The attachment body 44 is longer than the thickness of the aligner 16 at the cutout edge, and such embodiment can prevent the aligner 16 from sliding over the top surface 62 of the attachment body 44.

Referring to Figure 5 to 11 , one projection 28 extends toward the interior of the cutout 24. More than one projection may be provided in other embodiments. A part of the projection 28 is at the gingival side of the attachment body 44 and contacts the attachment body 44 at the contact point 36 when the aligner 16 is in its fully installed position 34; referring to Figures 12 to 18, a height of the attachment body44 is greater than the thickness of the aligner 16 at a cutout edge 26 of the cutout 24. The height of the attachment body 44 may be at least 1.4 times the thickness of the aligner 16 at the cutout edge 26 in some cases, and may be at least 1.8 times the thickness of the aligner 16 in a few cases. The side surface 60 of the attachment body 44 is dimensioned to inhibit the part of the projection 28 from sliding over the top surface 62 of the attachment body 44. This functions during an insertion and a dislocation of the aligner, and functions when the aligner is fully installed 34. The part of the projection 28 and the attachment body 44 is dimensioned to resiliently engage with each other to hinder displacement of the aligner from its fully installed position 34. All the features shown in these figures may be applied in any embodiment of the cut out and attachment and combined with other features of the embodiment.

Referring to Figure 19, the attachment 18 in some embodiments includes a wing 52 that extends radially away from the attachment body 44 distal from the base 46. The wing 52 typically extends wider than the attachment body 44. The wing 52 in some embodiments is elliptical as shown in Figure 20. Other shapes of the wing 52 are possible, and in general the wing 52 may have any suitable shape. In some embodiments (not shown), the attachment 18 including any wing 52 is dimensioned to act as a hook, e.g. for dental traction component(s).

Referring to Figure 21 providing a side view along lines 21-21 of Figure 19, the attachment 18 defines a slot 54 between the wing 52 and the tooth surface 13. The slot 54 is dimensioned to constrain the aligner 16 and its cutout edge 26 between the tooth surface 13 and the wing 52 to prevent the projection 28 (Figure 5 et al.) from sliding overtop surface 62 of the attachment body 44 when the aligner 16 is displaced from its fully installed position 34. The slot 54 width is equal to the distance between the wing 52 and the tooth surface 13 (or the base when the attachment has an enlarged base 46). The width of the slot 54 is bigger than the thickness of the portions of the cutout edge 26 that pass within the slot 54.

Referring to Figure 22, the base 46 in some embodiments has a bevel 50 to provide a sloped guide of the aligner 16 into the slot 54. The slot 54 in general may have any suitable shape, including being smoothly rounded at its edges for example. In this embodiment the slot 54 width is equal to the distance between the wing 52 and the base 46, and the width of the slot 54 is bigger than the thickness of the portions of the cutout edge 26 that pass within the slot 54.

Referring to Figure 23, the wing 52 typically extends beyond the width of the attachment body 44 at the contact point(s) 36 and does not necessarily (although it may) extend beyond the width of the attachment body 44 elsewhere. In some embodiments, the wing 52 and the slot 54 are one-sided as shown in Figure 23.

Referring to Figure 24, the slot 54 has an opening toward the aligner 16 and the opening is greater than the thickness of the aligner 16 at the cutout edge. In this embodiment, the opening of the slot 54 is greater than the thickness of the aligner 16 and some other parts of the slot 54 is not as great as the thickness of the aligner 16 at the cutout edge.

Referring to Figure 21 to 24, the slot 54 at its opening has a width that is greater than the thickness of the aligner 16 at the cutout edge. This embodiment can keep the cutout edge of the aligner 16 sliding in the slot 54 without sliding over the top surface 62 of the attachment body 44. All the features shown in these figures may be applied in any embodiment about the cutout and attachment and combined with other features.

Referring to Figures 12 to 24, a height of the attachment body 44 is greater than the thickness of the aligner 16 at a cutout edge 26 of the cutout 24. In some cases the height of the attachment body 44 is at least 1.4 times the thickness of the alignerl 6 at the cutout edge26, in a few cases at least 1.8 times the thickness of the aligner 16 at the cutout edge 26; A part of the aligner 16 is at the gingival side of the attachment body 44 and contacts the attachment body 44 at the contact point 36 when the aligner is in its fully installed position34 (referring to Figure 5). The side surface 60 of the attachment body 44 is dimensioned to inhibit the part of the aligner 16 from sliding over the top surface 62 of the attachment body 44, this may function during an insertion or a dislocation of the aligner, and may function when the aligner is fully installed 34; the part of the alignerl 6 and the attachment body 44 being dimensioned to resiliently engage with each other to hinder displacement of the aligner 16 from its fully installed position34; In most cases at least part of the side surface 60 of the attachment body44 forms one of an acute and a right angle with the tooth surface, In a few cases at least part of the side surface 60 of the attachment body 44 may form an angle with the tooth surface less than 130 degrees; The attachment 18 may comprise a wing 52 separated from the base 46, the wing 52 being dimensioned to prevent the part of the aligner 16 from sliding over the top surface 62 of the attachment body44 when the alignerl 6 is being displaced from its fully installed position34. All the features shown in the figures may be applied in any embodiment having the innovative cutout and attachment. By applying the features shown in these figures, a side surface 60 of an attachment body 44 may also be dimensioned to inhibit a part of an aligner 16 next to the cutout, which is not at the gingival side of the attachment body when the aligner is fully installed34, from sliding over a top surface 62 of the attachment body.

Referring to Figures 25 to 27, the cutout edge 26 of the aligner 16 in some embodiments defines more than one projection 28. In the exemplary embodiment of Figure 25, the aligner 16 includes one cutout 24 whose cutout edge 26 defines a pair of opposing projections 28 that form a passage 56 between the opposing projections 28. As the aligner 16 is installed onto the dental arch 14, the attachment body 44 (not visible in Figures 25 to 27) passes through the passage 56 as the pair of projections 28 pass through the slot54 defined by the base 46 and the wing 52. While in the exemplary embodiment of Figure 25 the projections 28 forming the passage 56 are mirror images of each other, in general each projection 28 may have any suitable shape and size.

Referring to Figure 28, the top view of the attachment body 44 (i.e. the attachment 18 with its base 46 and wing 52 removed for clarity) reveals a pair of contact points 36 between the attachment body 44 and each projection 28 when the aligner is in its fully installed position 34, and the tip of the two projections 28 are at the lingual side of the attachment body 44, referring to Figure 25 to 27 the projection 28 and the attachment 18 are dimensioned to resiliently engage with each other to hinder displacement of the aligner 16 from its fully installed position.

Referring to Figures 29 to 31 , the attachment body 44 has a cross-sectional shape that may be any suitable shape, and the cutout 24 may have any suitable shape. Examples of various shapes for the attachment body 44 and cutout 24 are shown in Figures 29 to 31 , including the diamond-shaped cutout 24 of Figure 31. Referring to Figure 30, part of the attachment body 44 may extend out of the cutout 24. In this situation the projection 28 is at the gingival side of part of the attachment body 44, and the projection 28 is at the gingival side of the attachment body protrusion 64.

Referring to Figure 32, the attachment body 44 in some embodiments has a cross- sectional shape that is diamond-shaped. The diamond-shaped cutout 24 that conforms to the diamond-shaped attachment body 44 advantageously provides a strong retention force. Referring to Figures 32, the aligner 16 in some embodiments includes one or more secondary cutout(s) 58 or window(s) 88 that are dimensioned to not engage with any attachment 18 when the aligner 16 is in its fully installed position 34. The secondary cutout(s) 58 increase the flexibility of the aligner 16 material, thereby decreasing the retention force required to move the projection 28 past the attachment 18, and thus makes intentional installation and removal of the aligner 16 easier while advantageously causing no minor displacement of the aligner 16.

Referring to Figures 25 to 32, the aligner 16 comprises two projections 28, each one of the projections 28 extending toward the interior of the cutout 24. A part of the each one of the projections 28 is at the gingival side of at least part of the attachment body 44 and contacts the attachment body 44 when the aligner 16 is in its fully installed position 34. The part of the projection 28 and the attachment body 44 being dimensioned to resiliently engage with each other to hinder displacement of the alignerl 6 from its fully installed position 34. The features shown in these figures may be applied in any embodiment having the innovative cutout and attachment.

Figures 33 to 35 illustrate embodiments where no aligner projection 28 is provided at the gingival side of the attachment body 44 when the aligner is fully installed 34. The part of the aligner 16 next to the cutout 24 has force engagement with a side surface of the attachment body 44 when the aligner 16 is fully installed. This contacting part of the aligner is not at the gingival side of the attachment body 44. The side surface of the attachment body 44 is dimensioned to inhibit this part of the aligner 16 from sliding over a top surface of the attachment body 44. All the features shown in Figure 12 to 24 and Figure 38 to 41 may also applied to the embodiments shown in Figure 33 to 35. By applying the features shown in Figure 12 to 24 and Figure 38 to 41 , a side surface 60 of an attachment body 44 may be dimensioned to inhibit a part of an aligner 16, which is not at the gingival side of the attachment body, from sliding over a top surface 62 of the attachment body in the embodiments shown in Figure 33 to 35. In these embodiments at least part of the aligner next to the cutout may be spaced away from the tooth surface such that an aligner bulge 105 over an unoccupied space feature 100 is formed next to the cutout 24. This arrangement can make this part of the aligner more flexible and generate more gentle orthodontic force. Part of the aligner may be spaced away from a side surface of the teeth when the aligner is fully installed, such that one or more aligner bulges 105 over an unoccupied space feature 100 are formed at a tooth next to the repositionable tooth or two adjacent teeth next to the repositionable tooth. This arrangement can make this part of the aligner more flexible and generate more gentle orthodontic force. Part of the aligner may be spaced away from an occlusal surface of the teeth when the aligner is fully installed, such that at least two aligner bulges 105 over premolars and canines of the teeth are applied at the right side of the aligner 16 and at least two aligner bulges 105 over premolars and canines of the teeth are applied at the left side of the aligner 16. The shape of the aligner bulge 105 is similar to a natural tooth cusp. Occlusal contacts on these aligner bulges is helpful to keep the aligner in its fully installed position 34. Intermaxillary elastic or intramaxillary elastic may be applied with the attachment to get a better orthodontic result.

In these embodiments an inner surface 90 of the aligner 16 may be engaged with the attachment body 44 when the aligner is fully installed 34. In these embodiments, an outer surface 92 of the aligner may be engaged with the attachment body 44 when the aligner 16 is fully installed 34. In these embodiments, an edge of the cutout 24 may be engaged with the attachment body 44 when the aligner is fully installed 34. In these embodiments a part of the aligner 16 may have force engagement with the attachment body 44 at an occlusal side surface 47, or a mesial side surface 48, or a distal side surface 49 of the attachment body 44 when the aligner 16 is fully installed 34. The part of the aligner 16 may have force engagement with more than one side surfaces of the attachment body 44.

A side surface of the attachment body 44 comprises an occlusal side surface 47, a mesial side surface 48, a distal side surface 49, and a gingival side surface 45. Referring to Figure 33, part of the aligner 16 has force engagement with an occlusal side surface 47 of the attachment body 44 when the aligner 16 is fully installed 34, and the aligner 16 has at least one contact point 36 with the occlusal side surface 47 and the mesial side surface 48 of the attachment body 44. This arrangement may cause the tooth a torquing movement.

Referring to Figure 34, part of the aligner 16 has force engagement with a mesial side surface 48 of the attachment body 44 when the aligner 16 is fully installed 34. This arrangement may cause tooth to move distally.

Referring to Figure 35, part of the aligner 16 has force engagement with a distal side surface 49 of the attachment body 44 when the aligner 16 is fully installed 34. This arrangement may cause tooth to move mesially.

Referring to Figure 36, in some embodiments the projection tip 30 extends to contact the other projection tip 30 at the opposite side of the passage 56, and the passage 56 is opened by the attachment body 44 during the insertion and removal of the aligner 16. The passage 56 is opened as the attachment body 44 passes through the passage 56 and separates the contact between the opposing projection tips 30 by squeezing the respective projections 28. After insertion or removal of the aligner 16, the respective projections 28 relax to re-close the passage 56 and resume contact between the respective projection tips 30 at the passage 56. Referring to Figure 37, in some embodiments the projection tip 30 extends to contact a different portion of the aligner 16 at the other side of the passage 56, and the passage 56 is opened by the attachment body 44 during the insertion and removal of the aligner 16. The passage 56 is opened as the attachment body 44 passes through the passage 56 and compresses the projection 28 to separate the contact between the projection tip 30 and the other portion of the aligner 16. After insertion or removal of the aligner 16, the projection 28 relaxes to re-close the passage 56 and resume contact between the projection tip 30 and the other portion of the aligner 16.

Figure 38 is a side sectional view of part of a dental arch14 with an aligner 16 fully installed 34 on it, showing that a part of the aligner 16 next to a cutout 24 of the alignerl 6 is engaged with an attachment 18 and an aligner bulge 105 over an unoccupied space feature 100 is formed. A part of a projection of the aligner 16 is at the gingival side of the attachment body 44 and contacts the attachment body 44 (referring to Figures 5 to 11). The attachment 18 has a base 46 and a body 44. An aligner 16 is in its fully installed position 34. A cutout 24 of the aligner 16 has an opening at the gingival edge of the aligner 16 and the cutout edge 26 defines a projection 28. the part of the projection 28 is at the gingival side of the attachment body 44 and engages with the attachment body 44 to hinder displacement of the aligner 16 from its fully installed position 34. The aligner 16 next to the cutout 24 is spaced away from the tooth surface 13, such that an aligner bulge 105 over an unoccupied space feature 100 is formed next to the cutout 24. The cutout edge 26 is in force engagement with the attachment body 44. This unoccupied space feature 100 under the aligner bulge 105 can increase the flexibility of the aligner 16 and make the engagement force between the cutout edge 26 and the attachment body 44 more gentle and long lasting. This force is an optimal orthodontic force.

The projection of the aligner 16 engaged with the attachment body 44 at the gingival side of the attachment body 44 is not visible in Figure 38.

This innovation of having an aligner bulge 105 over an unoccupied space feature 100 is applied together with the other innovation features of the attachment 18 and the cutout 24 in this embodiment. The unoccupied space feature100 is defined by the aligner 16 and one of the tooth surfaces 13 and the attachment base 46. The unoccupied space feature 100 has a definitive shape and has an unoccupied volume of space. The feature of having an aligner bulge over an unoccupied space feature next to a cutout may be applied in any embodiments having the innovative cutout and the attachment.

The engagement force between the cutout edge 26 and the attachment body 44 may be influenced by the unoccupied space feature 100 under the aligner bulge 105. Usually, the engagement may cause the aligner 16 to deform, and the deformation of the alignerl 6 may generate an orthodontic force. The aligner 16 delivers an orthodontic force to the tooth by the engagement between the cutout edge 26 and the attachment body44. An unoccupied space featurelOO under the aligner bulge 105 makes the aligner 16 above the unoccupied space featurelOO more flexible. The orthodontic force generated by the aligner’s deformation become more gentle and long lasting, which provides an optimal orthodontic force.

Figures 39 to 41 are side sectional views of the portion shown in Figures 12 to 18, showing a part of an aligner 16 around an attachment 18 and showing the engagement between the part of the aligner 16 and the attachment body 44 when the aligner 16 is in its fully installed position 34, and showing the part of the alignerl 6 at the gingival side of the attachment body 44 contacts the attachment body 44 at a contact point 36. All the features shown in these figures may be applied in any embodiment mentioned above and still encompass the advantages of the cutout and the attachment. By applying the features shown in these figures, a side surface 60 of an attachment body 44 may also be dimensioned to inhibit a part of an aligner 16 next to the cutout, which is not at the gingival side of the attachment body 44 when the aligner 16 is fully installed, from sliding over a top surface 62 of the attachment body 44.

Referring to Figure 39, the inner surface 90 of the aligner 16 engages with the attachment body 44 when the aligner 16 is in fully installed position 34. The aligner inner surface 90 has at least one contact point 36 with the side surface 60 of the attachment body 44.

Referring to Figure 40, the inner surface 90 of the aligner 16 engages with the attachment body 44 when the aligner 16 is in fully installed position 34. The aligner inner surface 90 has at least one contact point 36 with the side surface 60 of the attachment body 44. An aligner bulge 105 over an unoccupied space featurelOO is formed next to the attachment body 44. Indeed, the aligner bulge 105 is also next to the cutout 24 because the attachment body 44 is in the cutout 24.

Referring to Figure 41 , the outer surface 92 of the alignerl 6 engages with the attachment body 44 when the aligner 16 is in fully installed position 34. The aligner outer surface 92 has at least one contact point 36 with the side surface 60 of the attachment body 44. An aligner bulge 105 over an unoccupied space featurelOO is formed next to the attachment body 44. The aligner bulge is also next to the cutout 24 because the attachment body 44 is in the cutout 24.

The attachments mentioned in these embodiments are dimensioned for use with one or more aligners during the treatment. Figure 12 is a side sectional view of Figure 5. Figures 13 to 18 are variations of the embodiment shown in Figure 12. Figure 5 shows a part of an aligner is at the gingival side of an attachment body and contacts the attachment body at a contact point when the aligner is fully installed. Figures 12 to 18 show different attachment body designs and shows ways of engagement between the attachment body and the part of the aligner at the contact point when the aligner is in its fully installed position, and the features shown in these figures can be applied in any embodiments having the cutout and the attachment. For example, the embodiment described in Fig. 11 may have an attachment as described in Fig.18 and follow the way of engagement between the attachment and the aligner described in Fig.18 when the aligner is in fully installed position. As another example, the embodiment described in Figure 32 may change its attachment to the attachment described in Fig. 17 and follow the way of engagement between the attachment and the aligner at the contact point described in Figure 17 when the aligner is in fully installed position, and this combination makes a new embodiment. The way of contact engagement showed in these Figures may also be applied to any contact engagement between an attachment and a part of an aligner which is not at the gingival side of the attachment.

Figures 19 and 20 are two variations of the attachment. These variations may be applied in any embodiments mentioned herein above. For example, the embodiment in Fig.

1 to 5 may change its attachment to the attachment described in Fig. 19, and this combination makes a new embodiment.

Figure 21 to 24 are four variations of the attachment, whereby these variations may be applied in any embodiments mentioned herein having the cutout and the attachment. These figures of side sectional view of the attachment show different attachment design and different ways of engagement between the attachment body 44 and a part of an aligner 16 at the contact point 36 when the aligner is in fully installed position, and the part of the aligner 16 is at the gingival side of the attachment body 44 when the aligner is fully installed. These attachments and these ways of engagement between the part of the aligner and the attachment may be applied in any embodiments about the innovative attachment and the cutout. For example, the embodiment described in Figure 10 may use the attachment described in Figure 22 and follow the way of engagement between the attachment and the aligner at the contact point described in Figure 22 when the aligner is in its fully installed position. This combination makes a new embodiment. As another example, the embodiment described in Fig. 31 may have an attachment described in Fig. 23 and follow the way of engagement between the attachment and the aligner at the contact point described in Figure 23 when the aligner is in fully installed position, and this combination makes a new embodiment. The way of contact engagement showed in these figures may also be applied to any contact engagement between an attachment and a part of an aligner which is not at the gingival side of the attachment.

Figures 25 to 28 show a second embodiment with two aligner projections. Figures 29 to 32 shows some variations of the second embodiment. Figures 33 to 35 shows the case when the aligner projection 28 is not applied at the gingival side of the attachment body 44.

Figures 38 to 41 provide novel forms of engagement between the aligner and the attachment body, these engagements may be applied to any embodiment of cutout and attachment. For example, the embodiment described in Figure 31 may change its attachment to the attachment described in Figure 41 and follow the way of engagement between the attachment and the aligner at the contact point described in Figure 41 when the aligner is in its fully installed position.

All the figures in a side sectional view of the embodiments show different features with all the Figures in a top view of the embodiments , such that all the features shown in the figures of a side sectional view may be applied together with all the features shown in the figures of a top view to form an embodiment having the cutout and attachment.

This innovation of an aligner spaced away from a tooth surface and having an aligner bulge 105 over an unoccupied space feature 100 can be applied in other cases to generate a gentle and long lasting orthodontic force to get better orthodontic treatment results.

Aligners are used to reposition a tooth from one tooth arrangement to the next tooth arrangement, whereby each aligner is formed according to the next tooth arrangement and a repositionable tooth remains at the one tooth arrangement before the aligner is installed.

The discrepancy of the positions of the repositionable tooth between the one and the next tooth arrangements causes the aligner to deform when the aligner is fully installed for the first time. This aligner deformation mainly take place at the aligner around the repositionable tooth and next to the repositionable tooth, where the positional discrepancy is greatest. The deformation of the aligner generates orthodontic forces to cause tooth repositioning. If the aligner next to the repositionable tooth is made more flexible, the orthodontic force generated by the aligner deform becomes gentler and long lasting. Having part of the aligner spaced away from a tooth surface creates an aligner bulge over an unoccupied space feature formed at one or more teeth next to the repositionable tooth. This innovative idea makes the aligner more flexible and the shape of the aligner bulge changes as the position of the repositionable tooth changes. The unoccupied space feature is designed to have a definitive shape and has an unoccupied volume of space.

Figure 42a and Figure 42b are different views of one embodiment for combining employment of an aligner having an aligner bulge and having a cutout engaged with an attachment. Referring to Figure 42a, this is a horizontal cross section view of part of a dental arch 14 with an aligner 16 fully installed on it. The lower second molar 201 and the lower first premolar 204 are programmed to be repositioned, so an attachment 18 is cemented on the lower second molar 201 , and another attachment 8 is cemented on the lower canine 205. These two attachments have a base 46 and an attachment body 44. An aligner 16 is fully installed on these teeth with two cutouts 24 of the aligner held resiliently in place by the attachments to hinder displacement of the alignerl 6 from its fully installed position. An aligner bulge 105 over an unoccupied space feature100 is formed next to the cutout 24 on the lower second molar 201. Additional aligner bulges 105 over unoccupied space features 100 are formed over the side surfaces 106 of the lower first molar 202. The height of these two aligner bulges is preferably less than 1.5 mm. The lower first molar 202 has at least one contact point 36 with the aligner 16 at the mesial part of the tooth side surfaces 106. More aligner bulges over unoccupied space features100 are formed at the lower second premolar 203, the lower second premolar 203 having at least one contact point 36 with the aligner 16 at the most protrusive parts 107 of the two side surfaces 106 of tooth 203. More than one aligner bulge 105 are formed at the teeth next to the repositionable teeth. Another attachment 18 is cemented on the side surface 106 of the lower canine 205, whereby the attachment body 44 is engaged with the cutout edge 26. Tooth side surfaces 106 in this application refer to tooth surfaces 13, other than occlusal surface108 of a tooth. Tooth side surfaces 106 include a buccal surface, a lingual surface, a mesial surface and a distal surface of a tooth.

Figure 42b is a vertical sectional view of part of a dental arch 14 with an aligner 16 fully installed 34 on it. An aligner bulge 105 over an unoccupied space feature 100 are formed on the lower first molar 202 and the lower second premolar 203. The lower first molar 202 has contacts 36 with the aligner 16 at tooth cusps 102 and the lower second premolar 203 has contact 36 with the aligner 16 at tooth cusp 102. A tooth cusp 102 is the most prominent part 107 at an occlusal surface.

The aligner’s projections 28 engaged with the attachment bodies 44 are at the gingival side of the two attachments bodies 44 but are not visible at Figures 42a and 42b.

The aligner 16 has at least one contact point 36 with the most prominent part 107 of the buccal and lingual surfaces of the tooth 203, and the tooth 203 is next to the repositionable tooth 204. The aligner has at least one contact point 36 with the tooth cusp 102 on the occlusal surface 108 of tooth 202 and tooth 203, and these cusps are the most prominent parts 107 on the occlusal surface 108 of tooth 202 and tooth 203. Tooth 202 is next to the repositionable tooth 201 , and tooth 203 is next to the repositionable tooth 204. Referring to Figures 42a and 42b the alignerl 6 has contact with the tooth 203 only at the most prominent parts 107 of the surfaces of the tooth 203, the part of the aligner next to the repositionable tooth is become more flexible.

In some cases, an aligner is designed to contact a tooth surface of a tooth next to the repositionable tooth only at the most prominent part of the tooth surface.

In some cases, an aligner bulge 105 which covers part of a tooth surface of a tooth is not a protrusion, and the most prominent part of the aligner 16 over the tooth surface is touching the most prominent part 107 of the tooth surface when the aligner is fully installed 34.

In some cases, an aligner bulge 105 which covers part of a tooth surface of a tooth is not a protrusion, the most prominent part of the aligner 16 over the tooth surface is touching a top surface 114 of an attachment 112 at the tooth surface when the aligner is fully installed 34.

In some cases, an aligner bulge covers part of a tooth surface of a tooth, the aligner bulge is next to one of the repositionable teeth.

An aligner bulge 105 over an unoccupied space feature100 may be applied with more than one aligner in an orthodontic treatment. In an orthodontic treatment a dental arch may have more than one repositionable tooth arranged to be repositioned by an aligner.

In this embodiment, part of the aligner spaces away from the tooth surface and an aligner bulge 105 over an unoccupied space feature 100 is formed next to the cutout 24 on the repositionable tooth 201. The other aligner bulges are formed at the teeth next to the repositionable teeth when the aligner 16 is in its fully installed position. The attachments 18 mentioned in this embodiment are not traditional attachment. These attachments 18 and the aligner 16 around the cutout 24 are dimensioned to engage with each other to hinder the aligner 16 dislocating from its fully installed position 34.

Figure 43a and Figure 43b are different views of one embodiment having an aligner bulge 105 over an unoccupied space featurel 00 applied together with the traditional attachments 112.

Figure 43a is a horizontal cross section view of part of a dental arch 14 with an alignerl 6 fully installed on it. Four traditional attachmentsl 12 are cemented on the: lower first molar 202, lower second premolar 203, lower first premolar 204 and lower canine 205. Lower first molar 202 and lower canine 205 are programmed to be repositioned. Two aligner bulges over unoccupied space features 100 are formed at the lower second premolar 203, and one of the two aligner bulges is formed over one traditional attachment 112 cemented on a side surface106 of the lower second premolar 203. The aligner 16 has no contact with the traditional attachment 112 on the tooth 203. The other aligner bulge 105 is formed at another side surface 106 of the lower second premolar 203 such that the aligner has no contact with the side surface 106. One aligner bulge 105 is formed at the lower first premolar 204, and this aligner bulge 105 is formed next to a traditional attachment 112 cemented on a side surface106 of the first premolar 204. The aligner 16 has no force engagement with the traditional attachment 112. The aligner has at least one contact point 36 with the top surface 114 of the traditional attachment 112 on the tooth 204. The aligner 16 has contact and force engagement with the other traditional attachmentsl 12 cemented on the lower first molar 202 and the lower canine 205. Side surfaces 106 of a tooth crown include a buccal surface, a lingual surface, a mesial surface, and a distal surface.

Figure 43b is a vertical cross section view of part of a dental arch14 with an aligner 16 in its fully installed position, the alignerl 6 in contact with the occlusal surfaces108 of these teeth.

An aligner bulge over an unoccupied space feature may be applied with more than one aligner in an orthodontic treatment. In an orthodontic treatment, a dental arch may have more than one repositionable tooth arranged to be repositioned by an aligner, and the orthodontic appliance may have more than one attachments covered by an aligner bulge, and the orthodontic appliance may have more than one attachments next to an aligner bulge.

In this embodiment, the aligner bulge 105 over an unoccupied space feature100 is formed over a side surface106 of tooth 203 and is also formed over the traditional attachment 112 on the side surface 106, such that the aligner 16 has no contact with this traditional attachment 112, and a height of the aligner bulge 105 is less than 2mm. For the tooth 204, the aligner bulge over an unoccupied space feature100 is arranged next to the traditional attachment 112 on a side surface 106 and the aligner 16 has at least one contact point 36 with the top surface 114 of the traditional attachmentl 12, and the most prominent part of the aligner over the tooth surface 106 of the tooth 204 is touching the top surface 114 of the attachment 112 when the aligner 16 is fully installed 34. In these two situations the aligner 16 has no force engagement with the traditional attachments 112. Usually the aligner 16 has force engagement with the traditional attachment 112 which is covered by the aligner 16. However, by employing the aligner bulge over an attachment, the aligner 16 has no force engagement with the attachment 112, such that the alignerl 6 become more flexible and provide a gentler orthodontic force. In this case the aligner bulges 105 are formed at the teeth next to the repositionable teeth.

In some case the aligner bulge 105 covers part of a tooth surface of a tooth, the most prominent part of the aligner 16 over the tooth surface is touching a top surface 114 of an attachment 112 at the tooth surface when the aligner is fully installed 34. The aligner bulge over an unoccupied space feature 100 applied together with the traditional attachmentsl 12 in this embodiment on lower second premolar 203 and lower first premolar 204 may increase the flexibility of the aligner 16 over these two teeth, whereby the two traditional attachmentsl 12 has no force engagement with the alignerl 6. The aligner 16 may generate gentler and long-lasting force to the lower first molar 202 and lower canine 205, and this force is an optimal orthodontic force providing a good orthodontic result.

Figure 44a and Figure44b are different views of one embodiment showing an aligner bulge over an unoccupied space feature applied over teeth without any attachment.

Figure 44a is a horizontal cross section view of part of a dental arch 14 with an aligner 16 in its fully installed position 34, whereby first lower molar 202 is programmed to be repositioned by the aligner 16. Each one of two aligner bulges covers part of a side surface 106 of the lower second molar 201 , and the remaining part of the side surfacesl 06 of the lower second molar 201 have good contact with the aligner 16. A height of these aligner bulges is less than 2 mm, and these aligner bulges are next to the repositionable tooth 202. Aligner bulges cover two side surfaces 106 of lower second premolar 203, and these two side surfaces 106 have no contact with the aligner 16. In some case, a height of an aligner bulge may be less than 1.5 mm. In some case, a height of an aligner bulge may be less than 1 mm, or even less than 0.5 mm. A height of an aligner bulge may be similar to a height of an aligner receptacle of a traditional attachment, in most cases the height of an aligner bulge is less than the height of an aligner receptacle, in some case an aligner bulge is not a protrusion, and the aligner bulge may not engage with a muscle around a dental arch.

Figure 44b is a vertical cross section view of part of a dental arch 14 with an alignerl 6 in its fully installed position 34. The aligner bulge 105 is formed on an occlusal surface of lower second premolar 203. Referring to Figure 44a, aligner bulges cover two side surfaces 106 of lower second premolar 203, such that the lower second premolar 203 has no contact with the aligner 16.

The aligner bulges 105 over unoccupied space features 100 are formed on the lower second molar 201 and the lower second premolar 203, which are next to the repositionable tooth 202. The deformation of the aligner 16 reduces as the repositionable tooth 202 approaches the intended tooth position, and the shape of the aligner bulge 105 changes.

In an orthodontic appliance for repositioning teeth from an initial tooth arrangement to a final tooth arrangement, the teeth form an upper dental arch and a lower dental arch, the orthodontic appliance comprises a plurality of aligners associated with a plurality of tooth arrangements, the plurality of tooth arrangements comprise the initial tooth arrangement and the final tooth arrangement, the plurality of aligners comprise upper aligners dimensioned for installation on the upper dental arch and lower aligners dimensioned for installation on the lower dental arch, each said aligner is dimensioned to reposition the teeth from one tooth arrangement to a subsequent tooth arrangement.

Figure 45 is a vertical cross section view of part of a dentition with the upper dental arch 116 of a patient separated from his lower dental arch 118, showing that a wedge space120 exists between the occlusal surfaces108 of the upper dental archl 16 and the occlusal surfaces108 of the lower dental arch 118 when an upper aligner16 and a lower aligner 16 are in their fully installed position 34. At least one of the upper dental arch 116 and the lower dental arch 118 comprise at least one repositionable tooth which is arranged to be repositioned relatively to other teeth in the same dental arch. If the aligner 16 has the same thickness along its occlusal surface 124, only the lower aligner occlusal surface 124 over the lower second molar 201 permits contact with the upper aligner occlusal surface124. This may lead to intrusion of the lower second molar 201 and the upper second molar 206 and back teeth open bite at the end of the treatment. To solve this problem, one or more aligner bulges over an unoccupied space feature 100 should be employed, such that an occlusal surface 124 of the lower aligner 16 over at least one of lower premolars and lower canines of the teeth may permit contact with the upper aligner 16 when the aligners 16 are fully installed. Each one of the aligner bulges 105 may only cover part of an occlusal surfaces 108 of a tooth when the aligners are fully installed, for example covering only a tooth cusp 102 of a tooth.

Figure 46a is a vertical cross section view of part of a dentition with the upper dental archl 16 of a person separated from his lower dental arch 118 when upper and lower aligners16 are fully installed34, a wedge space120 exist between the occlusal surfaces108 of the upper dental arch 116 and the occlusal surfaces108 of the lower dental archl 18 (refer to Figure 45). At least one of the upper dental arch 116 and the lower dental arch 118 comprise at least one repositionable tooth which is arranged to be repositioned relatively to other teeth in the same dental arch. This figure only shows part of the dentition, where usually a whole dentition of a patient comprises 4 upper incisors, 2 upper canines, 4 upper premolars, 4 upper molars, 4 lower incisors, 2 lower canines, 4 lower premolars, and 4 lower molars. The aligners are spaced away from part of an occlusal surface of the teeth, with 6 aligner bulges formed over an occlusal surface of premolars and canines of this part of the dentition. The aligner bulge 105 over the upper second premolar 208 and the aligner bulge 105 over the lower second premolar 203 has at least one contact point 36. The aligner bulge 105 over the upper first premolar 209 and the aligner bulge 105 over the lower first premolar 204 have at least one contact point 36. The aligner bulge 105 over the upper canine 210 and the aligner bulge 105 over the lower canine 205 have at least one contact point 36. Aligner bulges over unoccupied space features 100 are formed over the cusps 102 of these premolars and canines in upper dental arch 116 and lower dental archl 18. This arrangement is helpful for correcting the anterior teeth’s deep bite and preventing aligner displacement. In this embodiment, the aligner bulges are arranged over an occlusal surface of each one of premolars and canines of the teeth and each one of the aligner bulges covers part of an occlusal surface of one tooth. Each one of the aligner bulges at the lower aligner permit contact with the aligner bulges at the upper aligner when the aligners are fully installed. Usually, each dental arch has 2 premolars and 1 canine at the right side of the dental arch and 2 premolars and 1 canine at the left side of the dental arch. So in this case,

3 aligner bulges are arranged at each side of the upper aligner and 3 aligner bulges are arranged at each side of the lower aligner. In some cases, an aligner bulge may cover part of an occlusal surface of two adjacent teeth of the teeth, and in other cases an aligner bulge may cover only part of an occlusal surface of one tooth. In this embodiment, each one of the aligner bulges covers only a cusp of one tooth of the teeth. The aligner bulge has a shape and a size, which are similar to a tooth cusp. The aligner may have a shape similar to a natural tooth cusp and has a size bigger than a natural tooth cusp.

By employing the method mentioned above, at least one of the lower aligner and the upper aligner may have at least 2 aligner bulges formed at the right side of that aligner and at least 2 aligner bulges formed at the left side of that aligner when the aligners are fully installed.

By employing the method mentioned above, at least one of the lower aligner and the upper aligner may have at least 3 aligner bulges formed at each of the right and the left side of that aligner.

By employing the method mentioned above, at least 2 aligner bulges over an occlusal surface of premolars and canines may be applied at the right side of an aligner and at least 2 aligner bulges over an occlusal surface of premolars and canines may be applied at the left side of the aligner when the aligner is fully installed, this arrangement may be applied to the upper aligner or the lower aligner or applied to both.

By employing the method mentioned above, at least 3 aligner bulges over an occlusal surface of molars, premolars and canines may be applied at the right side of an aligner and at least 3 aligner bulges may be applied over an occlusal surface of molars, premolars and canines at the left side of the aligner, this arrangement may be applied to the upper aligner or the lower aligner or applied to both.

By employing the method mentioned above, the aligner bulges of the lower aligner or the upper aligner may permit contact with the other aligner when the aligners are fully installed. An aligner bulge may have a shape and a size, which are similar to a natural tooth cusp, such that an aligner bulge of one of the aligners may have a few contact points with the occlusal surface of the other aligner. In this case an occlusal surface of one of the aligners over premolars and canines of the teeth permits contact with the occlusal surface of the other aligner when the aligners are fully installed, by employing aligner bulges. This is helpful to keep the aligners fully installed and helpful to prevent the back teeth having an open bite. This is also helpful to correct the anterior deep bite and helpful to reposition teeth. The patient feels more comfortable with the lower dental arch having freedom to do all kinds of occlusal movements.

Figure 46b is a vertical cross section view of part of a dentition with an upper dental arch 116 of a patient separated from his lower dental archl 18 when an upper aligner and a lower aligner are in their fully installed position. At least one of the upper dental archl 16 and the lower dental arch 118 comprise at least one repositionable tooth which is arranged to be repositioned relatively to other teeth in the same dental arch. Compared with Figure 46a, the only difference is that the part of the aligner which has an aligner bulge over an unoccupied space feature 100 is replaced by part of the aligner having thicker material 101 than other parts of the aligner. This embodiment has the same function as the embodiment shown in Figure 46a, the difference is that the aligner is less flexible due to the part of the aligner with greater thickness.

In this case an occlusal surface124 of the lower aligner over each one of lower premolars and lower canines of the teeth permits contact with the upper aligner when the aligners are fully installed.

Figure 47 is a vertical cross section view of part of a dentition with an upper dental arch 116 of a patient separated from his lower dental arch 118 when the upper and lower aligner are fully installed. An occlusal surface124 of the lower aligner 16 over each one of lower molars, premolars and the canines of the teeth permits contact with the upper aligner when the upper and lower aligner are fully installed. Aligner bulges105 over unoccupied space features100 are formed over the cusps 102 of these premolars and canines of the upper and lower dental arch, and an aligner bulge over an unoccupied space feature is also applied over a molar cusp 102 except the molar cuspl 02 at the ends of a dental arches. No aligner bulge is formed over the distal cusps of the second molars 201 and 206 in this embodiment. An aligner bulge may have a shape similar to a natural tooth cusp, such that an aligner bulge of one of the aligners may have a few contact points with the occlusal surface of the other aligner. In this case an occlusal surface of one of the aligners over each one of molars, premolars and canines may permit contact with the occlusal surface of the other aligner when the aligners are fully installed, the contact engagement between the upper and lower aligners when the aligners are fully installed is similar to the natural occlusal contact engagement between the upper dental arch and the lower dental arch. This is helpful to keep the aligners fully installed and helpful to prevent the back teeth’s open bite from happening. This is also helpful to correct the anterior deep bite and helpful to reposition teeth, patient feel comfortable with a lower dental arch having freedom to do all kinds of occlusal movements.

In this embodiment, the aligner bulge over an unoccupied space featurelOO may be replaced by a part of the aligner having thicker material. Both embodiments may prevent the back teeth from open bite and aligner displacement.

Figure 48a is a vertical cross section view of part of a dentition with one upper incisor 126 of a person separating from his lower incisor 128 when the upper and lower aligner are fully installed, an aligner bulge 105 over an unoccupied space feature 100 is formed over an incisor edge 130 of the upper incisors 126 and another aligner bulge 105 over an unoccupied space feature 100 is formed over an incisor edge130 of the lower incisor128. An incisor edge132 of the lower aligner 16 permits contact with the upper alignerl 6. In this situation, the upper and lower anterior teeth experience an intrusion force, and this arrangement can help to correct the anterior teeth’s deep bite. The aligner bulge 105 over an unoccupied space featurelOO may be only formed over the incisor edge130 of the lower incisor 128 to achieve a similar treatment result. By employing the same method of this embodiment, at least one of the lower alignerl 6 and the upper aligner 16 is spaced away from part of a surface of the teeth such that one or more aligner bulges 105 is formed over an incisor edgel 30 of anterior teeth when the aligners16 are fully installed, such that an incisal edgel 32 of the lower alignerl 6 permits contact with the upper alignerl 6 when the aligners16 are fully installed. In some cases, only an incisal edge132 of the lower alignerl 6 permits contact with the upper aligner 16 when the aligners 16 are fully installed.

By employing the method mentioned above, an occlusal surface of one of the aligners over each one of molars, premolars, canines, and incisors may permit contact with the other aligner when the aligners are fully installed.

Referring to Figure 48b, compared to Figure 48a, the aligner bulge 105 over an unoccupied space featurelOO in Figure 48a is replaced by making part of the aligner thicker than other parts of the aligner. Both embodiments may correct the anterior teeth deep bite. By employing the same method of this embodiment, part of the lower alignerl 6 at a location around an incisor edgel 30 of the lower anterior teeth is thicker than other parts of the lower aligner, such that an incisal edge 132 of the lower aligner16 permits contact with the upper alignerl 6 when the aligners are fully installed 34. In some cases, only an incisal edgel 32 of the lower alignerl 6 permits contact with the upper alignerl 6 when the aligners are fully installed.

Figures 49 to 52 illustrate a method of manufacturing an orthodontic appliance for repositioning teeth, the orthodontic appliance comprising at least one aligner 16 having at least one cutout 24 which has an opening at a gingival edge of the aligner 16 when the aligner 16 is fully installed.

The method comprises the following steps:

(a) referring to Figure 49, providing a positive model of a dentition having at least one added structure 99 on a tooth surface 15 of the model;

(b) referring to Figure 49, forming the aligner 16 over the positive model and over the added structure 99 such that the aligner 16 includes an aligner protrusion 94 at the added structure location; and

(c) referring to Figure 50, cutting across the aligner protrusion 94 by an automatic cutting machine to form a cutout 24 of the alignerl 6 having a cutout edge 26 raising away from a tooth surface15 of the model.

The added structure is a non-dental structure, i.e. it does not form part of the patient’s initial or final tooth arrangement in the dentition model. Instead the added structure is designed to provide a sacrificial protrusion for subsequent cutting steps.

Dentition modelling may use common knowledge in the field of orthodontics to obtain a digital model of a dentition of a patient using a digital scanner, such as iTero. After the repositioning treatment has been design, a plurality of modified digital dentition models can be defined having a plurality of tooth arrangements. One of the modified digital dentition models and a digital model of an added structure can be merged into a combined digital model. A positive model of the combined digital model can be printed out by a 3D printing machine using existing techniques and materials. Similarly, method to program the aligner tooth arrangements by computer are well known. The auto edge-cutting machine for aligner may be a CNC laser or cutting machine. The edge cutting machine may cut the edge for the aligner and cut the aligner protrusion to form a cutout.

In this embodiment, the added structure 99 is applied at the location the cutout 24 is desired, and the aligner protrusion 94 is formed over the added structure 99. The aligner protrusion 94 provides a cross-section along the cross-section line 98 and this cross-section forms the desired cutout 24.

In some embodiments, the added structure extends vertically to a gingival side of the model of the dentition, so that the cutout has an opening toward the gingival side of the aligner, i.e. towards the gingiva of the teeth when the aligner is fully installed. The opening of the cutout toward the gingiva is made by the automatic cutting machine, which cuts laterally across the aligner protrusion 94 and cuts across the aligner 16 along its gingival margin to form the aligner edge.

Referring to Figure 50 the aligner protrusion 94 may have at least one sidewall 95 extending at an angle of more than 60 degrees relative to the model tooth surface 15 (i.e., the surface plane at the location of the protrusion) when the aligner is fully seated on the model. The cross-section line 98 is parallel to the model tooth surface 15, the angle 78 between the aligner protrusion sidewall 95 and the cross-section Iine98 is more than 60 degrees, such that the sidewall 95 extends at an angle of more than 60 degrees relative to the model tooth surface 15.

Referring to Figure 50, in an improved embodiment the aligner protrusion 94 has a base 97 which extends laterally beyond a distal part of the protrusion. That is, the base of the protrusion is wider than its distal portion. By cutting across the distal part of the aligner protrusion 94, (referring to Figure 51) an aligner bulge over an unoccupied space feature100 is formed next to the cutout 24 when the alignerl 6 is in its fully installed position34.

Referring to Figure 52, the method may comprise cementing an attachment 18 to the tooth surface 13 and installing the aligner onto the teeth by resiliently engaging the attachment 18 with a part of the alignerl 6 next to the cutout 24 to hinder displacement of the aligner 16 from its fully installed position.

Figure 53 and 54 shows an improved embodiment, the aligner protrusion 94 having two sidewalls 95 extending substantially orthogonal to the model teeth surface15 at the location of the protrusion 94 when the aligner is seated on the model. Referring to Figure 53, the cross-section line 98 is parallel to the model tooth surface 15, the angle 78 between the aligner protrusion sidewall 95 and the cross-section line is 90 degrees, such that the sidewall 95 extends at an angle of 90 degrees relative to the tooth surface 13.

The aligner manufacturing is formed on model tooth surface 15. After manufacturing, the aligner is installed on the tooth surface 13.

All cutting machines have positioning tolerances, so the cutout location will vary from expected when cutting orthogonally into the side of the aligner. By precisely defining the cutout location with the protrusion and then cutting laterally through the protrusion, the manufacturing tolerance only affects the standoff distance to the aligner surface. When the sidewall 95 of the protrusion is very steep, e.g. extending at an angle more than 60° relative to the tooth surface, preferably substantially 90°, production accuracy is greatly improved.

Reference list

Orthodontic appliance 10 Teeth 12

Tooth surface 13

Dental arch 14

Model tooth surface 15

Aligner 16

Aligner gingival edge 17

Attachment 18

Ridge 20

Indentation 22

Cutout 24

Cutout edge 26

Projection 28

Projection tip 30

Insertion route 32

Fully installed position 34

Contact point 36

Displaced position 38

Inner edge 40

Attachment body 44

Gingival side surface 45

Base 46

Occlusal side surface 47

Mesial side surface 48

Distal side surface 49

Bevel 50

Wing 52

Slot 54

Passage 56

Secondary cutout 58

Side surface of attachment body 60

Top surface of attachment body 62

Attachment body protrusion 64

Attachment body protrusion tip 68

Compressive force 72

Vertical component force 74

Horizontal component force 76 Angle 78

Window 88

Aligner inner surface 90

Aligner outer surface 92

Aligner protrusion 94

Aligner protrusion sidewall 95

Cross section 96

Aligner protrusion base. 97

Cross section line 98

Added structure 99

Unoccupied space feature 100

Aligner with bigger thickness 101

Tooth cusp 102

Occlusal plane 103

Aligner bulge 105

Tooth Side surface 106

Most protrusion part 107

Tooth Occlusal surface 108

Traditional attachment 112

T op surface of traditional attachment 114

Upper dental arch 116

Lower dental arch 118

Wedge space 120

Aligner cusp 122

Aligner occlusal surface 124

Upper incisor 126

Lower incisor 128

Incisor edge 130

Aligner incisor edge 132

Lower Second molar 201

Lower First molar 202

Lower Second premolar 203

Lower First premolar 204

Lower Canine 205

Upper Second molar 206

Upper First molar 207 Upper Second premolar 208 Upper First premolar 209 Upper Canine 210 Usage of relative terms, such as “lower, upper, inner, outer, under, over, and on top of,” are intended to simplify understanding of the apparatus when in normal use. While embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only. The invention may include variants not described or illustrated herein in detail. Thus, the embodiments described and illustrated herein should not be considered to limit the invention as construed in accordance with the accompanying claims.