DESCRIPTION

FIELD OF THE INVENTION The present invention relates to a dental appliance adapted to fit on a dental arch, as well as to a corresponding system for preparing to use the appliance, a corresponding treatment method and a corresponding method of manufacturing the appliance; the method of manufacturing may advantageously incorporate a specific design method. STATE OF THE ART

Chemical substances for whitening teeth are known; some of these chemical substances are in the form of a gel.

Fungicidal, anti-inflammatory, antimicrobial, antibacterial and antiviral chemical substances for teeth and/or gums are also known; some of these chemical substances are in the form of a gel.

The application of these substances to the surfaces of the teeth and/or gums for performing a treatment is done manually.

More generally, the application of chemical substances to the surfaces of a person's teeth and/or gums is done manually, and therefore requires expertise not possessed by that person. In fact, tooth and/or gum chemical treatments are carried out by specialised personnel. Obviously, this does not apply to chemical substances that are little (or not) reactive and/or little (or not) harmful or dangerous, such as toothpastes.

SUMMARY Thus, there is a need to apply chemical substances to tooth and/or gum surfaces in a manner that is precise (i.e. in the places where it is needed and in the amount needed), selective (i.e. not in the places where it is not needed) and reliable, i.e. requiring little attention and/or expertise on the part of the person doing the application (who may even be the “owner” of the teeth). In particular, such need is perceived for whitening chemical substances and for anti inflammatory, antimicrobial, antibacterial and antiviral substances.

Such need is achieved thanks to what is set forth in the claims that are an integral part of the present description.

The appliance according to the present invention has a simple structure, but still allows effective, precise and customised treatments. In addition, it is easy to produce accurately using 3D printing techniques.

The appliance may be advantageously used, for example, to whiten teeth (which is an aesthetic treatment) or for the prevention of carious processes or the formation of bacterial plaque (which are preventive therapeutic treatments) or for the treatment of dental or gum diseases (which are curative therapeutic treatments) because it allows to place the chemical substance in specific areas, for example of each tooth, where the pockets of the body are located.

In addition, the appliance is advantageously customisable to the dental arch of a specific person; for example, according to some embodiments it may be a bespoke tray for whitening teeth treatments. In fact, the body composing it typically and advantageously derives from an impression (physical or digital) of the dental arch that is to be submitted to the chemical substance application.

LIST OF THE FIGURES

The present invention shall become more readily apparent from the detailed description that follows to be considered together with the accompanying drawings wherein:

Fig. 1A shows a positive cast of an (upper) dental arch,

Fig. IB shows the arch cast of Fig. 1A with a fitted embodiment of a dental appliance according to the present invention,

Fig. 1C shows a three-dimensional view (from above) of the embodiment of the appliance of Fig. 1A,

Fig. ID shows a sectional view of the embodiment of the appliance of Fig. 1A at an incisor tooth,

Fig. 2 shows a front view of the embodiment of the appliance of Fig. 1 with an edge seal,

Fig. 3 shows a section view of a tooth (such as the one indicated with the arrow in Fig. 2) on which an appliance according to the present invention is fitted that is provided with a pocket of a first possible type (just the one shown in Fig. 2), Fig. 4 shows a section view of a tooth (such as the one indicated with the arrow in Fig. 2) on which an appliance according to the present invention is fitted with a pocket of a second possible type (which is a variant of the one shown in Fig. 2),

Fig. 5 shows a partial front view of a tooth on which an appliance according to the present invention is fitted having a pocket with seal,

Fig. 6 shows a section view of the tooth of Fig. 5 on which an appliance according to the present invention is fitted with a pocket with a seal,

Fig. 7 shows a detailed view of a section of a first possible seal at the edge of an appliance according to the present invention,

Fig. 8 shows a detailed view of a section of a second possible seal at the edge of an appliance according to the present invention,

Fig. 9 shows a detailed view of a section of a third possible seal at the edge of an appliance according to the present invention, and Fig. 10 shows an embodiment of a system for preparing to use a dental appliance according to the present invention.

As it can be easily understood, there are various ways of practically implementing the present invention which is defined in its main advantageous aspects in the appended claims and is not limited either to the following detailed description or to the appended drawings.

DETAILED DESCRIPTION

The dental appliance according to the present invention is adapted to fit on a person's dental arch; see, for example, the appliance 100 in particular as shown in Fig. 1. It must be noted that Fig. 1A actually shows a positive cast 10 of a dental arch, but, for the purposes of the hereinafter explanation, it may be assumed that the element referred to as 10 is also the dental arch itself.

It comprises a body 110 that typically and advantageously derives from a physical or digital (3D) impression made on the person prior to making the body; for example, a 3D scan of the dental arch can be made directly or a physical impression of the dental arch may be taken and then a scan of the impression may be made or a positive cast of the dental arch may be taken and then a scan of the cast may be made. The body 110 could advantageously be produced by a 3D printing process directly or indirectly; in the latter case, a mould is produced by 3D printing and then the body is thermoformed from the mould.

The body 110 is provided with a cavity 120 also essentially derived from the impression, but which is modified in part typically by 3D computer design (this will be better understood later).

In addition, the body 110 is provided with an edge 150 that is typically derived from the impression, but may also typically be modified by 3D computer design (this will be better understood later).

The cavity 120 has a surface configured to adhere at least to the surfaces of the teeth of the dental arch (as the person skilled in the art understands, we do not mean herein the entire surface of all the teeth but an appropriate percentage); the adhesion of the surface is perfect or substantially perfect precisely because it derives from an impression.

The edge 150 surrounds the cavity 120 and is configured to adhere at least to the gum of the dental arch (as the person skilled in the art understands, we do not mean herein the entire surface of the gum, but an appropriate percentage); the adhesion of the surface is perfect or substantially perfect precisely because it derives from an impression; it should be noted that the edge may typically be adapted to be positioned at least partially at the collar of the teeth of the dental arch.

According to the present invention, the surface of the cavity 120 has at least one pocket 130 defining a space 131 adapted to house a chemical substance adapted to chemically act on an area of a surface of a tooth and/or of the gum when the dental appliance 100 is fitted on the dental arch of the person (it should not be excluded that, for certain applications, a single pocket may be used to obtain a chemical action on, for example, two teeth and/or on a peripheral area of the surface of, for example, one tooth or two teeth or on a tooth and a portion of a gum or on two teeth and a portion of a gum); see for example Fig. 3 and Fig. 4.

For the utmost clarity, it must be specified that the present invention (and thus the corresponding methods and apparatuses) aims at treating specific areas of the surface of one or more teeth and/or of the gum, but not at treating simultaneously and equally the entire surface of all the teeth of a dental arch and/or the entire surface of the gum of an oral cavity; in particular, when the present description and/or the appended claims refer to the gum, reference is made to a portion of the gum.

Typically, there will be a certain number of pockets; for example, there could be one pocket for each tooth, as shown for example in Fig. 2; for example, some teeth may not be associated with a pocket or may be associated with two or three pockets. Typically, a pocket is associated with only one tooth. Typically, the area of a pocket is small, such as 10% to 90% or 20% to 80% or 30% to 70% of the inner or outer surface of a tooth.

The chemical substance is in the form of a gel, and is specifically a tooth-whitening or fungicidal and/or anti-inflammatory and/or antimicrobial and/or antibacterial and/or antiviral chemical substance for teeth and/or gums. It should be noted that depending on the application, the positions of the pockets in relation to the teeth and/or gum may be different.

Typically, the pocket is positioned in such a way that the chemical substance acts chemically on an area of an outer surface of at least or only one tooth or gum when the dental appliance is fitted on the person's dental arch, as shown for example in Fig. 3 and Fig. 4.

The pocket has a continuous and fluidically insulating containment surface at the appliance body, i.e. there are no openings and/or fluidic communication channels at the appliance body. Then, the pocket has to be filled with the chemical substance through its aperture facing the cavity.

The pocket faces directly the cavity when the dental appliance is not fitted and faces directly the area to be treated when the dental appliance is fitted. Thus, the appliance does not provide for or require an element or barrier adapted to contain the chemical substance in the pocket and prevent it from escaping, but takes advantage of the fact that the chemical substance is in the form of a gel.

The pocket may have a depth that varies from point to point. In the example of Fig. 3, the depth of the pocket 130 is substantially uniform except, of course, for the peripheral area wherein the surface of the pocket approaches the surface to be treated (of the tooth and/or gum) with an abrupt change in depth. In the example of Fig. 4, the pocket 140 may be considered to have basically two different depths; even then, there are areas where the depth varies abruptly. The possible usefulness of having a variable depth, for example a double depth as in Fig. 4, is related to the different amount of chemical substance at the different points of the surface to be treated (of the tooth and/or gum).

As it can be seen, particularly in Fig. ID, the body forms a kind of a shell for the teeth and part of the gum with a wall (totally or partially enveloping the teeth - the tips of all or some of the teeth may not even be enveloped by the wall) that is preferably rather thin, in particular 0.5 mm to 1.5 mm, and basically uniform in thickness; as it can be seen for instance in Fig. ID, if the thickness of the wall is thin, a “bulge” on the outer side of the wall corresponds to the “pocket” on the inner side of the wall, i.e. on the outer surface of the dental appliance. In fact, since the purpose of dental appliance is to contain a chemical substance and ensure that it remains in selective contact with the teeth and/or gums, it is not necessary for the wall to be thick. In addition, using a thin wall allows to obtain high comfort for the person “wearing” the dental appliance.

Typically, the surface of the cavity of the dental appliance according to the present invention has a plurality of pockets defining respectively a plurality of spaces adapted to house a chemical substance, in the form of a gel, capable of chemically acting on a corresponding plurality of areas of tooth and/or gum surfaces when the dental appliance is fitted on the dental arch. Each pocket may have one or more of the characteristics previously described. The pockets are generally different and may be of different types. It is possible that, in use, separate pockets contain different chemical substances. Preferably, the pockets are fluidically insulated from each other.

Then there are two particularly advantageous aspects that add to the benefit of the foregoing: the contour seal and the edge seal. Of course, these may both be present in some embodiments of the present invention, but this is not necessary. Advantageously, a seal 135 may be provided at the contour of a pocket 130; see for instance Fig. 5 and Fig. 6. This seal is for preventing the chemical substance from escaping from the pocket and ending up in areas where it is not desired. Such leakage could be caused, for example, by the operation of fitting the appliance on the arch and/or by excessive amounts of chemical substance placed in the pocket prior to the operation of fitting the appliance on the arch.

This contour seal may be a component applied to the body (thereby made separately from the body) or integrated into the body (thereby made at the same time as the body by means of a 3D printing process, for example). In particular, the contour seal may be made of a different material from the body.

Advantageously, a seal may be provided (see for instance items 155, 156, 157 in Fig. 7, Fig. 8, Fig. 9) at the edge 150 of the appliance 100, see for instance Fig. IB, Fig. 1C and Fig. 2. This seal is for preventing the chemical substance from escaping from the appliance and ending up in areas where it is not desired, especially in the mouth. Such a leakage could be caused, for example, by the operation of putting the appliance on the arch and/or by excessive amounts of chemical substance placed in the pockets prior to the operation of fitting the appliance on the arch.

This edge seal may be a component applied to the body (thereby made separately from the body) or integrated into the body (thereby made at the same time as the body, e.g. by a 3D printing process). In particular, the edge seal may be made of a different material from the body.

In Fig. 7, a first edge seal 155 is shown, consisting essentially of a single element, e.g. with a circular cross-section, which extends along the entire edge (or at least a large part) of the appliance body.

In Fig. 8, a second edge seal 156 is shown, consisting essentially of four elements like those in Fig. 7 placed side by side.

In Fig. 9, a third edge seal 157 is shown, essentially consisting of a kind of tape that extends along the entire edge of (or at least most of) the body of the appliance. Although in Figures 7-9 the seal is highlighted in relation to the body, the above clarification regarding its structure and material applies.

As will be further explained hereinafter, especially if the body of the appliance according to the present invention is made by means of a 3D printing process, the “design” of the pockets and/or edge and/or contour seal advantageously derives from a 3D computer design. In other words, a 3D digital impression of the dental arch is taken and then these elements are designed by computer directly on such impression thanks to a computer program (CAD software) that assists an operator, the so-called “designer”, in the design.

Such design may also make use of other information, such as colour images of tooth surfaces in the arch. Such images may be processed by a computer program (CAD software) in such a way that the surface of each tooth and/or gum is divided into a finite number of areas (e.g. one or two or three or four) within which the colour may be considered substantially uniform. The images thus processed can help to “design” the whitening treatment in such a way that it is extremely accurate; for example, one can design not only one, but also two or more different dental appliances (in terms of position and size of the pockets).

As it can be understood from the foregoing, before fitting the appliance on the arch, it is necessary to place the chemical substance in the pockets of the dental appliance. Such operation could be done manually, taking care to place in each pocket an amount of material (in the form of a gel) corresponding to the volume of the pocket itself; this requires care.

A system was therefore provided to ease such an operation of preparing the appliance before actually using it on the dental arch.

An embodiment of this system is shown in Fig. 10.

The system 200 comprises: a positive cast 210 of the dental arch having at least one duct 220 having an accessible inlet 220 and an outlet 224 at an aperture of one or, more typically, of each pocket when the dental appliance 100 is fitted on the positive cast 210, and a device 230 to inject the chemical substance into the accessible inlet 222 and push it into each pocket.

In particular, part of the duct 220 is outside the cast 210, as shown in Fig. 10.

In the example of Fig. 10, the duct 220 is branched and has only one accessible inlet 222 and a plurality of outlets 224, one for each pocket to be filled.

To prepare the appliance 100, the first thing to do is to fit the appliance 100 onto the cast 210, then fill e.g. a syringe 230 with the chemical substance (in the form of a gel), then inject the chemical substance with the syringe 230 until the pockets are filled, and finally remove the appliance 100 from the cast 210. The amount of chemical substance in the pockets of the appliance 100 is exactly the right one.

At this point, the real treatment may begin.

The treatments that are possible with the appliance according to the present invention may be divided into two categories: aesthetic treatments and therapeutic treatments. Treatments may concern the teeth and/or the gum. Among the aesthetic treatments, the main one is the treatment of whitening the tooth surface.

In general, a treatment method, in particular a tooth whitening or antimicrobial treatment, according to the present invention uses the dental appliance as defined above and comprises the steps of: a) filling the pockets of the appliance with a suitable chemical substance in the form of a gel, b) fitting the appliance onto the dental arch corresponding to the appliance (this is a correspondence in terms of shape and size that typically derives from the impression), c) waiting for a predetermined time, and d) removing the appliance from the dental arch.

It is worth pointing out that, in a treatment, these four steps could be repeated several times, such as two or three times, using different appliances (in terms of position and size of the pockets). Indeed, the teeth and/or gum may have areas that require different levels of treatment.

For the chemical reactions underlying the whitening mechanism, for example, hydrogen peroxide (H202) or carbamide peroxide (CH6N203), a substance consisting of equal amounts of hydrogen peroxide (H202) and urea (CO(NH2)2), may be used as whitening agents.

For antibacterial action, chlorhexidine (C22C12N 10H30), for example, may be used as an antibacterial agent. It has a bactericidal effect against Gram-positive and Gram-negative bacteria, which are the main responsible for oral infections that may also lead to the formation of caries and damage to teeth. Chlorhexidine may be used in varying concentrations ranging from 0.2% to 1% (in some cases even 2%).

For anti-inflammatory action, ibuprofen, for example, may be used as an anti inflammatory agent.

Treatments vary essentially according to the concentration of the agent within the chemical substance used for the treatments and according to the time of action of the chemical substance itself.

A method for producing a dental appliance according to the present invention is described hereinafter, which constitutes a further aspect of the present invention.

In general, the method comprises the steps of: a) acquiring directly or indirectly a digital impression of a dental arch in terms of shape, size and position and colour of the teeth and/or gum, b) assisting an operator in designing a dental appliance by operating on the digital impression using a computer taking into account the acquisition made, in particular the shape, size, position and colour of the teeth and/or gum, c) creating a 3D model of the dental appliance based on the design made, and d) 3D printing directly or indirectly the dental appliance based on the 3D model created.

As already mentioned, for the acquisition of the digital impression referred to in step a), either a direct 3D scan of the dental arch may be made or a physical impression of the dental arch may be taken and then a scan of the impression may be made or a positive cast of the dental arch can be taken and then a scan of the cast may be performed.

The acquisition of the colour may also take place simultaneously with the acquisition of shape and size and position, or by separate operations.

Typically, both tooth colour (which generally varies from point to point) and gum colour (which varies from point to point) may be acquired in the same operation. The colour is an important element not only in case of aesthetic treatments (e.g. whitening treatments), but also in the case of therapeutic treatments. In fact, the colour may provide indications about inflammation of the teeth and/or gum, and about attacks of fungi, microbes, bacteria and viruses on the teeth and/or gum. It should be noted that step a) may be implemented at a different time and place than steps b) and c). For example, step a) could be carried out by a dentist at his dental practice and then the data resulting from step a) (i.e. shape, size, position and colour of the teeth and/or gum of a dental arch) could be sent, for example, to a dental technician laboratory.

It should be noted that step d) may be carried out at a different time and place than steps b) and c). However, the widespread use of 3D printing equipment makes it likely that steps b), c) and d) are all carried out in the same place, e.g. in a dental technician laboratory.

As already mentioned, the body of the appliance may be printed by a direct or indirect 3D printing process; in this second case, a mould is produced by 3D printing and then the body is thermoformed from the mould.

Step b) is typically carried out using a computer program (CAD software) that assists an operator, the so-called “designer”, in the design; the operator may design the appliance on the computer in three dimensions, directly from the digital impression of the dental arch, including colour. It is not excluded that the program may give the operator suggestions in terms of the shape and/or size and/or position of the pockets, for example.

The design of step b) involves designing one or more pockets in particular in terms (for each pocket) of pocket position and extent and depth.

The design of step b) may involve designing one or more contour seals in terms (for each seal) of contour seal position and/or contour seal size and/or contour seal type. The design of step b) may involve designing an edge seal in particular in terms of position of the edge seal and/or size of the edge seal and/or type of the edge seal. Step d) may be performed using one material or using two different materials or using three different materials.

A first material is provided for the body of the dental appliance.

A second material may be provided for the contour and/or edge seals.

It is possible to provide a first material for the body, a second material for the contour seals, and a third material for the edge seal.

According to even more sophisticated embodiments of the production method, at step a) one or more tooth reference colours are also acquired, at step b) designing also takes into account the reference colours.

For example, the pockets may be accurately designed, taking specifically into account how the objective tooth and/or gum colouring is actually distributed in the dental arch with the aid of the computer.

To further assist in the step of designing the treatment (e.g. whitening) and thus of designing the dental appliance (or dental appliances), computer processing can be carried out on the digital arch acquired in step a) (in terms of shape, size, position and colour) prior to step b); such computer processing may comprise, for example, carrying out colour discretisation in a predetermined number of shades so as to highlight colour differences. For example, the surface of a tooth could be divided into two or three or four areas whose colour could be considered, to a first approximation, uniform; therefore, each of the two or three or four areas could require a different level of whitening. In this case, at step b), the design could also take this discretisation into account.

Especially in the light of the need for treatments, such as whitening treatments, of different levels and/or types on different areas of the teeth and/or gum, at step c) a plurality of 3D models of dental appliances differing from each other but related to the same dental arch may be created based on the design made, at step d) a corresponding plurality of dental appliances may be made by 3D printing based on the 3D models created.

In this case, typically, 3D models of such a plurality may differ in the position and/or extent and/or depth of one or more pockets.

The present invention has been so far described in general according to its various aspects.

Hereinafter, a description of an embodiment, complete according to its various aspects, will be given.

Embodiment

The proposal according to this embodiment relates to a new method of designing and producing whitening treatments customised to the patient's particular situation. The method is based on the use of a gel commonly used as a whitening chemical substance, which is normally distributed over the surface of the teeth by means of a splint of standard shape and size (or at the limit variable for predefined sizes). The proposed methodology involves customising the shape and size of the dental appliance according to the actual geometry of the patient's mouth and on the information of the initial tooth colour to customise and track the treatment. The treatment design step involves planning the chemical distribution areas using a supporting CAD tool and the manufacture of the dental appliance using advanced manufacturing technologies.

The following steps are provided: acquiring the geometry of the patient's mouth acquiring the starting colour of the patient's teeth designing the treatment designing the dental chemical substance application appliance manufacturing the dental appliance using the dental appliance Acquiring the geometry of the patient's mouth

The geometry of the patient's mouth may be detected by taking a physical impression or by acquiring a digital 3D scan. A physical impression may be taken either directly by the patient or by the dentist using a personal kit for acquiring the impression that includes a plastic or metal spoon and a specific impression material (usually silicone in one or more prepared and/or mixed steps). The physical impression must then be digitalised to allow to proceed with the following step of virtually designing the treatment. Digitalisation may be achieved by means of a scanning technique, which may allow to directly take the impression or alternatively the plaster cast of the impression itself.

Direct digital impressions can be taken by the dentist using a special 3D scanner that involves capturing the complete geometry of the mouth through a series of successive scans directly on the surface of the patient's teeth.

The step of acquiring the geometry of the patient's mouth makes it possible to obtain a 3D digital model of the patient's mouth describing the outer surface of the dental crowns and part of the surface of the gum with a high level of detail.

Acquiring the starting colour of the teeth

The initial tooth colour acquisition step aims at measuring timely and objectively the colour of natural or artificial teeth, regardless of the light condition. Acquisition may be carried out through the use of devices specifically intended for the purpose (spectrophotometers) or through the use of standard image acquisition technologies (cameras, video cameras, ...). The acquisition could also be carried out during the digital acquisition of the geometry of the mouth, if the intraoral scanner also allows the texture of the teeth to be acquired. Specimens with standard tooth colours could be placed side by side during the acquisition. Colour acquisition returns a colour map for the surface of the teeth (at least for the visible portion), which could be used to customise the areas to be treated in terms of geometry and amount of whitening material. The colour map of the acquired teeth (when this is not obtained directly with an intraoral scanner) is projected onto the geometry of the teeth in order to have a direct correspondence between the colour and the concerned areas. Designing the treatment

The treatment plan for teeth whitening involves applying the whitening chemical substance directly on the surfaces of the teeth to be treated based on the information acquired from the previous steps. In particular, reservoirs will be created to house whitening chemical substance directly proportional to the actual surface area of the specific tooth acquired during the step of detecting the geometry and if available based on the starting tooth colour detected by the colour acquisition step. A treatment plan may also provide subsequently the substance on the surface of the concerned teeth, varying the size of the application areas and their corresponding reservoirs.

The design is carried out with the aid of a CAD design tool that allows to select the portion of the concerned surface and to apply the relative amount of whitening chemical substance. If the texture of the teeth is present, the position, shape and size of the reservoirs may be selected (also automatically) on the basis of the information acquired (e.g. the characteristics of the initial tooth colour or the presence of any stains to be specifically treated). The treatment plan may also provide for several successive applications with incremental variation of the surfaces and application times.

Design of the dental substance application appliance

The design of the dental appliance is carried out so that the planned treatment may be implemented. In addition to the geometric aspect, which is related to the size of the reservoirs to allow applying the exact amount of whitening chemical substance on the specific tooth surface, the proposal addresses some of the problems arising from the use of whitening chemical substances. In particular, one of the problems is the risk of leakage of the whitening substance from the standard splint used for application. Such substance is only supposed to “wet” the tooth enamel, but, often, it also ends up on the gums. Since the substance is irritating to the gum tissues, this risk affects the type and amount of substance used, which are therefore chosen so as to preserve sensitive surfaces as much as possible. The risk is all the greater the more the geometry of the splint used for application deviates from the actual shape of the dental arch. In this perspective, using a customised dental appliance for substance application already actively counteracts this risk. The proposal aims at further increasing the effectiveness of the dental appliance by using specially-made solutions in terms of both the geometry and the materials used. In fact, the shape of the appliance is optimised to act as a seal for the whitening chemical substance on the tooth surface through the arrangement of specific geometric shapes on the edges of the reservoirs prepared at the step of planning the treatment and/or in general on the edges of the dental appliance near the patient's gums. The shapes that can be used are those generally used for seals in the machine industry. In order to be able to increase them further, specific materials are envisaged for these shapes and they are generally different from the materials used for the other parts of the appliance. The choice of material characteristics is made during the design step (e.g. softer material for the sealing areas and stiffer material for the other areas of the device). Another advantage of the digital approach to dental appliance design is the possibility to determine with certainty the exact amount of whitening chemical substance to be used for each treatment zone, which results in the design of the reservoir geometry on each tooth concerned. This makes it possible to know in advance the amount of substance to be used and avoids the use of a smaller amount, which could cause the substance not to be fully distributed over the entire surface to be treated, or a larger amount, which could instead lead to the leakage of the excess substance with the associated inconveniences mentioned above. The geometry of the dental appliance allows, as an additional advantage, to design a method of distributing the substance on the inner surface of the appliance based on the creation of a specially-made “filling mask” that allows the substance to be placed on the appliance in a controlled manner without having to proceed manually. The shape of the “dispenser” that includes the “filling mask” is obtained from the designed geometries by adding whitening chemical substance distribution channels that flow into a main flow channel to which a whitening chemical substance dispensing device is connected. This allows to fill in a simplified (and eventually automatic) and fast manner all the reservoirs, without the risk of under- or over dosing. Manufacturing the dental appliance

The designed dental appliances may be produced directly by means of additive techniques involving printing in biocompatible material (including multi-material), or indirectly by printing the designed models and thermoforming the final devices. Dispensers will be manufactured using additive technology. Using the dental appliance

The dental appliance thereby designed and manufactured provides the possibility of being used according to a specific clinical protocol that is also customised to the patient. In particular, it will be possible to provide the kit and the corresponding instructions for use directly to the patient. The kit comprises the mask(s) produced and the whitening material in the amount prescribed for the treatment. The patient shall place the material in the mask either manually or using the specific dispenser. The time of use will be indicated in the instructions and will take into account the amount of material required.