DENTAL SHIELD

[1] FIELD OF THE INVENTION

[2] The present invention relates to dental tools.

[3] TECHNOLOGICAL BACKGROUND

[4] More precisely, the invention relates to tools which are used when performing dental care on patients.

[5] In the field of dental care, it is known to use tools having an effective end, which is introduced into the mouth of patients for performing various operations. Because of saliva or water, dental operations may cause various sprays, splashes and spatters outside the mouth of the patient. Patients’ upper body (shoulders and chest) are generally protected with dental bibs. Dentists generally protect themselves with gowns, mask, glasses and gloves. Further part of the material used is single-use or is decontaminated from patient to patient. However, spray, splashing or spatter could still reach other surfaces, sometimes more than one meter away or stay in suspension. There is then a risk of contamination for the following patient, as it is unfortunately impossible to use only single-use equipment in a dental practice or to decontaminate efficiently and quickly the air. The projections from the patient’s mouth may also contaminate the practitioner and/or the dental nurse, if the very outmost protections (FFP2 masks, goggles, full facial shield, surgical cap and overcoat) are not used.

[6] The invention thus aims at reducing the risks of contamination and spreading of any illness in a dental practice.

[7] SUMMARY OF THE INVENTION

[8] Thus, the invention relates to a dental shield comprising:

- a sheet of translucent material, the sheet having transverse dimensions comprised between five and forty centimeters, and

- a holding system assembled to the sheet, the holding system comprising a through opening having a main axis and enabling a dental tool to extend through the shield and a retention system designed to retain the holding system and the dental tool to one another....

[9] Thus, the invention makes it possible to protect the surroundings of the mouth of the patient from spatters and splashes, while still enabling the dentist to apply the necessary treatment. [10] According to various aspects, one or more of the following features may be implemented.

[11] According to some embodiments, the sheet has rounded edges, with no sharp angles. [12] According to some embodiments, the sheet is rigid.

[13] According to some embodiments, the sheet is deformable.

[14] This arrangement makes it possible to adapt the sheet according to the shape of the patient’s mouth.

[15] According to some embodiments, the holding system is central and the sheet of translucent material is peripheral around the holding system.

[16] According to one embodiment, the holding system is eccentric relative to the sheet. This allows the practitioner to have a better view of the patient’s mouth.

[17] According to some embodiments, the holding system comprises an assembly portion for assembly to the sheet, and the sheet is overmolded on the assembly portion.

[18] According to one embodiment, the holding system and the sheet are releasably assembled.

[19] This makes it possible to change the sheet 2 attached to a given holding system, or to change the holding system attached to a given sheet. [20] According to one embodiment, the holding system comprises an attachment portion comprising a female portion that cooperates with the sheet for assembly to the sheet.

[21] This makes it possible to assemble successively different sheets (with different shapes and/or size) with the holding system. According to some embodiments, the sheet has a surface-treated first surface and an opposite second surface.

[22] According to some embodiments, the retention system is a releasable retention system, and optionally comprising one or more of :

- a magnetic retention system adapted to cooperate with a ferro-metallic retention portion of dental tool for retention,

- an elastomer retention system adapted to be deformed to a compressed configuration elastically retaining the dental tool, - a mechanical retention system comprising indents shaped to cooperate with external shapes of the dental tool to retain the dental tool.

[23] This makes it possible to assemble and disassemble a dental shield and a dental tool.

[24] According to some embodiments, the through opening of the holding system comprises a central through opening and the holding system comprises a least one tooth that protrudes towards the central through opening.

[25] This allows to form a contact surface between a dental tool and the holding system that is not continuous around the dental tool. Thus, the friction force between a dental tool and a dental shield that is assembled thereto may be reduced, and the positioning of the dental shield is easier.

[26] According to some embodiments, at least one tooth if the holding system is elastically deformable in at least one direction orthogonal to the main axis of the through opening of the holding system.

[27] In this case, the contact surface between a dental tool and a holding system assembled thereto can evolve, for example depending on how the holding system is positioned relative to the dental tool. Thus, if the dental tool as an elongated shape along a main axis, it will be possible to move the holding system relative to the dental tool along the main axis even if the section of the dental tool increases or decreases when one moves along this axis.

[28] According to some embodiments, at least one tooth of the holding system is elastically deformable in the direction of the main axis of the through opening of the holding system.

[29] This also makes it possible both to retain the dental tool with the holding system due to friction and to voluntarily easily move the dental tool relative to the holding system. It also allows to insert different dental tools having different shapes into the through opening of the holding system.

[30] According to some embodiments, the opening has an adjustable shape.

[31] This makes it possible to mount the holding system on various dental tools and to reposition the holding system on a given dental tool, for example during a care.

[32] According to another aspect, the invention relates to a system comprising a holding system of a dental shield and a dental tool passing through the through opening of the holding system and retained to the holding system of the dental shield. [33] In one embodiment, the system further comprises the sheet of the dental shield.

[34] BRIEF DESCRIPTION OF THE DRAWINGS

[35] Embodiments of the invention will be described below, in relation to the following drawings :

[36] Fig. 1 is a top view of a dental shield according to a first embodiment.

[37] Fig. 2 is a sectional view along line ll-ll of figure 1 of the embodiment of figure

1.

[38] Fig. 3 is a top view similar to figure 1 for a second embodiment.

[39] Fig. 4 is a side view of a dental shield according to a third embodiment.

[40] Fig. 5 is a side view of an example of a dental tool.

[41] Fig. 6 is a top view of a dental shield according to a fourth embodiment.

[42] Fig. 7 is a side sectional view of the dental shield of figure 6 through the through opening.

[43] Fig. 8 is a view similar to figure 7 of the shield according to the embodiment of figures 6 and 7 assembled to the dental tool.

[44] Fig. 9 is a view similar to figure 8 for a fifth embodiment of a dental shield assembled to another dental tool.

[45] Fig. 10 is an exploded side view of a sixth embodiment of a dental shield.

[46] Fig. 11a is a top view of an embodiment of a holding system 3.

[47] Fig. 11b is a lateral view of an embodiment of a holding system 3.

[48] Fig. 12a is a top view of an embodiment of a holding system 3.

[49] Fig. 12b is a cross-sectional view of the embodiment of a holding system 3 of figure12a along a plane (xOz) orthogonal to (xOy).

[50] Fig. 12c is a top view of the embodiment of the dental shield of figure 12a assembled with a dental tool 8.

[51] Fig. 13a is a top view of an embodiment of a dental shield without dental tool 8

[52] Fig. 13b is a top view of the embodiment of the dental shield of figure 13a assembled with a dental tool 8. [53] On the drawings, the same reference signs show the same or similar objects.

[54] DETAILED DESCRIPTION

[55] Fig. 1 shows a shield 1 according to one embodiment of the invention. The shield 1 comprises a sheet 2 and a holding system 3 attached to the sheet 2.

[56] The sheet 2 has a thickness dimension e which is notably lower than the two other dimensions of the sheet 2.

[57] The thickness is for example uniform, but it can also vary along one ore more directions. The thickness is about 0.1 millimeter (mm) to 5 millimeters, for example about 1 mm to 5 mm. For example, the thickness of the screen is less than 1.5 mm, so that its weight is low and does not reduce the maneuverability of a tool equipped with a shield.

[58] A low thickness also allows to make use of two screens either on the same tool or on two different tools placed at the same time in the patient’s mouth without preventing the practitioner from seeing inside the patient’s mouth through both screens. For example, if a suction tool and a polishing devices are used at the same time, they can be both equipped with a screen. If the two screens are thin enough, the visibility of the patient’s mouth remains satisfactory for the practitioner.

[59] The other two transverse dimensions of the sheet 2 are of the same order of magnitude. Typically, a transverse dimension D of the sheet is about five centimeters (cm) to forty centimeters.

[60] The sheet may have any suitable two-dimensional shape. For example, the two-dimensional shape is round, such as shown on Fig. 1, ellipse, oval or polygonal, or the like. Round, ellipse, oval or the like shapes show no sharp angles for the two- dimensional shape, which can be advantageous for the safety of the patient and/or the dentist. In addition, the edges 19 of the shield may be rounded.

[61] It has also been observed that an elliptic sheet adapts well to a patient’s mouth, thus providing a good protection against splashes or spatters.

[62] The sheet 2 has an annular shape with a main body 4 surrounding an opening 5. The opening 5 is a through opening.

[63] The opening 5 may be provided centrally, such as shown, or substantially centrally, with respect to the main body 5. [64] In variant embodiments, the opening 5 may not be centered with respect to the main body 4, such as shown on Fig. 3. In this case, the through opening 5 is eccentric. This embodiment allows good visibility for the practitioner.

[65] The sheet 2 is made of a translucent material. Any suitable translucent material might be used, such as translucent glass, translucent sapphire, translucent plastics, such as translucent acrylic.

[66] Translucency might be enhanced if the material used is scratch-proof or if the main surfaces of the material are scratch-proof.

[67] Further, the material can be ambient-light proof, so that translucency is not altered along time, in particular if the sheet 2 is reusable.

[68] In a particular embodiment, biodegradable plastic might be used, to enhance recyclability of the sheet 2. It may be convenient if the sheet 2 is single-use.

[69] A material will be considered translucent for the invention if it enables sufficient light to pass through for the purpose of the invention which is, for the dentist, to sufficiently see through the sheet into the mouth of the patient. The sheet ought not to impair the ability of the dentist to see inside the mouth of the patient. In particular, it could be transparent.

[70] According to one embodiment, the sheet 2 is rigid. Rigidity is defined as the ability of the sheet to hold a given shape, when no effort is applied to the sheet 2. According to one example, such as shown on Fig. 2, the shape is substantially planar. This is, the two main sheet surfaces 6a, 6b, are substantially planar and parallel to one another. However, according to one example, the sheet 2 might not be planar. For example, it may exhibit some degree of curvature out of a main plane, such as shown on Fig. 4. The concavity could be directed toward the patient. The curvature would typically be moderate, with an instantaneous radius of curvature of the order of the meter or the like. A rigid sheet may be provided in any of the above- listed materials.

[71] According to one example, the sheet 2 is deformable. Deformability is the ability of the shield to take different shapes. In particular, for each shape, the sheet 2 might be rigid. This could be obtained for example by providing a bistable sheet which may take two different rest configurations, when it is possible to elastically deform the sheet from one configuration to the other configuration by applying a mechanical stress on the sheet. A deformable translucent sheet 2 would typically be made of plastic. [72] The sheet 2 may be symmetric with respect to a central plane passing through the thickness of the sheet 2. In other embodiments, the sheet 2 may be asymmetric. In such case, the sheet 2 would comprise a patient side (that is to say a side facing the patient’s head) and a dentist side (that I sto say a side facing the dentist’s head).

[73] The sheet 2 may be positioned either above or below the practitioner’s hand.

[74] The patient-side and the dentist-side may have different properties. For example, the sheet may have an asymmetric shape, such as on the example of Fig.

4.

[75] The sheet 2 may comprise a hydrophobic material. The sheet 2 may also or alternatively be partially or totally anti-static and/or acid-proof.

[76] Alternatively, or in addition, one of the main faces of the sheet 2 may have a specific surface treatment. For example, the patientside main surface may have a non-stick surface treatment.

[77] In one embodiment, a prior treatment of the patient side surface with an invisible hydrophobic compound may be carried out. If the patient side main surface is hydrophobic, sprays and spatters are easier to remove from, or in case the patient side main surface of the sheet isn’t planar, water drops may trickle down in certain directions, for example towards a groove 24 as described below.

[78] The roughness of the patient-side main surface might be lower than the roughness of the patient-side main surface.

[79] Alternatively, or in addition, the patient side main surface may be more hydrophobic than the dentist side main surface. These provisions enable aerosols from the mouth of the patient not to stick to the patient side main surface of the sheet 2, and to flow and/or fall back on the patient.

[80] Alternatively or in addition, the sheet 2 may be provided with a groove 24 or furrow on the patient side, such as shown on the example of Fig. 3. Drops will flow on the patient side surface 6b into the groove 24, then in the groove 24 to a designed exit. One or more grooves may be provided.

[81] In one embodiment, the thickness of the shield can vary along one or more direction so that water drops are guided towards the groove and finally for example towards a recovery container or a patient’s dental bib.

[82] In one embodiment, the sheet 2 is single-use. [83] In another embodiment, the sheet 2 can be reused, provided that it is sterilized between two successive patients.

[84] In the shield 1 , a holding system 3 is attached to the sheet 2. The holding system 3 is designed to hold a dental tool 8, such as shown for example on Fig. 5. Therefore, the holding system 3 also comprises a through opening 7 having a main axis. The through opening 7 enables a dental tool 8 to extend through the shield 1. The main axis of the through opening 7 is sensibly orthogonal to the average plane of the sheet 2.

[85] The holding system 3 is provided in the opening 5 of the sheet 2. It is sealingly attached thereto. Attachment of the holding system 3 to the sheet 2 may be releasable or not and may be provided according to a plurality of embodiments, such as described below.

[86] Sealingly means here that no water can flow from the patient -side main surface of the shield 1 towards the opposite side through the interface between the holding system 3 and the sheet 2 when the shield is mounted on a dental tool 8.

[87] In one embodiment, the holding system 3 comprises an attachment portion 9 designed for attachment to the sheet 2.

[88] According to one embodiment, the sheet 2 and the holding system 3 are releasably attached to one another, so that it is possible to change the sheet 2 attached to one given holding system 3, or the holding system 3 attached to one given sheet 2.

[89] According to one example, as shown on Figs. 6 and 7, the holding system 3 comprises an annular ring 11 made of an elastomeric material, such as neopren or rubber for example.

[90] The elastomeric material may be overmolded on the annular sheet 2. In this case, the annular sheet 2 and the holding system 3 are permanently attached to each other in the dental shield.

[91] In the case shown on Figs. 6 and 7, the main axis of the through opening 7 is the revolution axis of the annular ring 11.

[92] The ring 11 might be a torus, as shown, or not. The ring 11 is here described with respect to its central axis. Hence, outer and inner portions are radially outer and inner portions, respectively, with respect to this axis. The outer ring surface 12 of the annular ring 11 forms the attachment portion 9 of the holding system 3 sealingly assembled to the sheet 2. The inner ring surface 13 of the annular ring 11 defines the through opening for letting through the dental tool 8.

[93] At rest, the inner radius r of the inner ring surface 13 is lower than the diameter of the dental tool 8. When the dental tool 8 is inserted through the through opening 7, the elastomeric material of the annular ring 11 is deformed, and is elastically pressing on the dental tool 8. This way, the dental tool 8 is retained on the shield 1, such as shown on Fig. 8, where the dental tool is only partially shown. The inner ring surface 13 of the annular ring 11 forms the retention system 10 of the shield 1. Typically, on Fig. 8, the shield 1 is retained on the dental tool 8 at the rear- end portion, or at the rear-end of the handling area 23.

[94] In one embodiment, the sheet 2 may have no degree of freedom relative to a holding system 3 with which it is assembled.

[95] In one embodiment, the sheet 2 may have one or more degree of freedom relative to the holding system 3. For example, the sheet 2 and the holding system 3 may be integral in translation along the axis of the dental tool 8, and the sheet 2 may rotate relatively to the holding system 3 around a symmetry axis of the holding system 3. In this case, the rotation of the sheet 2 may be limited by controlling the friction between the sheet 2 and the holding system 3, so that the sheet 2 only rotates when the practitioner is handling it for this purpose. In other words, the rotation is impossible if no torque is exerted on the sheet 2.

[96] To this end, the holding system 3 may be an annular ring 11, for example having the shape of a torus as shown on Fig.7, and the ring 11 may comprise on its outer portion a continuous and very thin central annular groove (or recess) 11b having the same axis as the ring 11 and the same mediator planes as the ring 11. This embodiment can be understood in the light of Fig. 11a (top view) and Fig. 11b (lateral view).

[97] In this case, the sheet 2 may rotate around the axis of the ring 11 , that is to say the main axis of the through opening 7. The thickness e of the groove 11 b is preferably close to the thickness of the sheet 2 along the through opening 7, so that the sheet 2 doesn’t rotate relative to the holding system 3 when no torque is exerted on it.

[98] More specifically, it may be possible to slip the sheet 2 into (or out of) the groove 11 b of the ring easily in one or more directions perpendicular to the axis of the ring 11 , so that the sheet 2 and the holding system 3 can be easily assembled or disassembled. In this case, the sheet 2 and the groove 11b may also fit together perfectly, that is to say without play between them along the axis of the ring 11 so that the rotation of the sheet 2 around the axis of the ring 11 is decided and controlled by the dentist.

[99] The depth p of the groove 11 b is chosen to ensure that the surface of the ring 11 delimiting the groove 11b forms a retention system 9. In this case, the retention is due to friction between the sheet 2 and the ring 11, and can be overcome if a the practitioner exerts a sufficient torque on the sheet 2 , for example if a relative rotation of the sheet 2 is needed.

[100] In this case, the attachment between the sheet 2 and the holding system 3 can be analyzed as follows : the retention system 9 of the holding system 3 - and more specifically the groove 11b - forms a female part, and the portion of sheet 2 along the through opening forms the complementary male part of a two-part attachment system. In this case, the holding system 3 and the sheet 2 are removably attached to each other, so that it is possible to change the sheet 2 while keeping the same holding system or to change the holding system 3 while keeping the same sheet 2.

[101] In this embodiment, the sheet 2 is easy to manufacture and inexpensive. This embodiment is particularly convenient for a single-use sheet 2.

[102] The holding system 3 may be a one-part system. It can for example be made of molded plastic, like molded polyethylene. In this case, the holding system 3 is easy to manufacture and unexpensive.

[103] Fig.10 shows an alternative embodiment for the holding system 3. In this embodiment, the holding system 3 is a two-part system. It comprises an outer part 14 and an inner part 15.

[104] The outer part 14 and the inner part 15 are releasably attached to one another using an attachment system 16.

[105] For example, the outer part 14 may comprise a first ring, called outer ring 12, and a second ring, called inner ring, releasably attached to each other.

[106] In this embodiment, the outer part 14 comprises the attachment portion 9 designed for attachment to the sheet 2. For instance, the outer ring 12 comprises a groove 11b as described above.

[107] The inner part 15 comprises the retention system 10 designed for the retention of the dental tool 8. The attachment system 16 may be any system enabling to releasably attach the outer part 14 to the inner part 15. It may for example comprise a mechanical attachment system such as a snap-fitting system, a bayonet mount or the like.

[108] The inner part 15 may comprise the retention system 10 designed for the retention of the dental tool 8. The attachment system 16 may be any system enabling to releasably attach the outer part 14 to the inner part 15.

[109] Hence, according to this embodiment, the shield 1 is a two-part product. The shield 1 comprises an outer device 17 and an inner device 18. The outer device 17 comprises the sheet 2 and the outer part 14 of the holding system. The sheet 2 and the outer part 14 of the holding system are sealingly assembled to one another, for example in a definitive way. The outer device 17 is integral. The sheet 2 is for example molded on to the outer part 14.

[110] The inner device 18 of the shield 1 comprises the inner part 15 of the holding system.

[111] This embodiment has the disadvantage to be more complex than a single piece holding system 3, but if several inner part 15 having different features are provided, it makes possible to easily change the inner part 15 in order to adapt it to another dental tool 8. This embodiment is as a consequence more adaptable, and can be less expensive and more eco-friendly in the long run than a single-piece holding system 3.

[112] As seen above, the holding system 3 comprises a retention system 10 to retain the dental tool 8 and the shield 1 together. Retention here is meant that moving the dental tool 8 assembled to the shield 1 would move the shield 1 as well.

[113] When a practitioner holds a dental tool 8 equipped with a shield 1 , the practitioner’s hand being below or above the shield 1, if the practitioner moves the dental tool 8, the shield 1 moves as well. This occurs even if the palm or the back of the practitioner’s hand is in contact with the shield 1.

[114] But if the practitioner voluntarily grasps the shield 1 and exerts a sufficient force or torque on the shield 1 , this may result in a translation and /or a rotation of the shield 1 relative to the dental shield 8.

[115] Hence, according to one example, the dental tool 8 is blocked by the shield 1, such that some degrees of freedom of the dental tool 8 are possible with respect to the shield 1. For example, the dental tool 8 may be inserted into the shield 1 by a translation movement along its longitudinal axis until reaching a stoppage position where the dental tool 8 is retained on the shield 1 by abutment. A backward movement of the dental tool by a translation movement along its longitudinal axis opposite the insertion movement remains possible. A rotation of the dental tool 8 with respect to the dental shield around its longitudinal axis is possible too.

[116] This makes it possible to correctly position the dental shield 1 for a subsequent care, or during a care.

[117] This arrangement is also advantageous for assembling a dental shield 1 with a dental tool 8.

[118] When the dentist assembles the dental tool 8 to the shield 1 , it involves inserting the dental tool 8 through the shield 1 , in particular through the through opening 7. In one of the embodiment of the holding system 3, this involves the dental tool 8 deforming the annular ring 11 of elastomeric material. The dental tool 8 is inserted so that its active end projects a few centimeters from the shield 1. The dental tool 8 is retained on the shield 1 in this position by the retention system 10. In particular, the elastomeric ring compresses the dental tool 8.

[119] In this case, one understands that the ring 11 must be able to stretch without tearing, in order to pass different diameters of the same instrument.

[120] As seen above at rest, the inner radius r of the inner ring surface 13 is lower than a diameter of the dental tool 8, for example the smallest diameter of the handpiece. When the dental tool 8 is inserted through the through opening 7, the elastomeric material of the annular ring 11 is deformed, and is elastically pressing on the dental tool 8. This way, the dental tool 8 is retained on the shield 1, such as shown on Fig. 8, where the dental tool is only partially shown. The inner ring surface 13 of the annular ring 11 forms the retention system 10 of the shield 1.

[121] In case the dental tool 8 doesn’t have a circular section, the form and the dimensions of the through opening 7 can be adapted to the dental tool 8 as shown on Fig. 1.

[122] In one embodiment, at least one characteristic dimension of the through opening 7 is smaller at rest than when a dental tool 8 is retained in it. In this way, when a dental tool 8 is inserted in the through opening 7, the holding system 3 is deformed and is elastically pressing on the dental tool 8.

[123] This arrangement also allows to use the holding system 3 on different dental tools 8 having different sizes. [124] To provide simultaneously sufficient elasticity and a capacity of abutment in a stoppage position, the holding system 3 may be an annular ring 11 as shown on Fig. 11a and Fig. 11b.

[125] The annular ring can further comprise indentations 7a. For example, in Fig. 1, the through opening 7 comprises a square central opening in continuity with four rectangular indentations.

[126] Another embodiment is shown on Fig.12a and Fig.12b, where the through opening 7 comprises a cylindrical central opening 7a in continuity with six indentations 7b.

[127] The solid parts (or material parts) of the holding system 3 adjoining the indentations 7b have the form of teeth 11c. One can also consider them as protrusions of a material part of the holding system 3 toward a central part of the through opening 7. In the case of Fig.13a, the section of the teeth 11 (in a plane orthogonal to the main axis of the through opening 7) is approximately triangular, whereas in the case of Fig 12a, it is approximately rectangular.

[128] The indentations 7b and the teeth 11c facilitate the stretching of the holding system 3 when one wants to insert a dental tool 8 through it.

[129] They also facilitate a translation of the holding system 3 relative to the dental tool 8 since the contact surface, and as a consequence the friction force, between the dental tool 8 and the holding system 3 is smaller than when the through opening 7 doesn’t comprise indentations. In this case, the contact surface between the dental tool and the holding system may not be continuous around the dental tool.

[130] Furthermore, the indentations 7b increase the range of diameters of dental tools 8 on which the dental shield 1 can be adapted. Indeed, the teeth 11c of the holding system 3 adjoining the indentations 7c may partially or totally be deformed and/or bend and/or flatten towards the indentations 7c.

[131] The dentist may need to use another dental tool 8’. If the dental tool 8’ has a different diameter than the dental tool 8, the same deformable ring may adapt various sizes of dental tools 8, 8’ thanks to one of the arrangement described above, as shown on Fig. 8 and Fig. 9, or on Fig. 13a and 13b , or on Fig.12a and Fig.12c. Hence, the shape of the opening 7 is adjusted to receive various dental tools.

[132] In the example showed on Fig.13a, if the holding system 3 is made of an elastomeric material, a through opening 7 having the shape of a cross, as on Fig.1 , thanks to rectangular indentations 7b, can adapt to a dental tool 8 having an elliptic section, as shown on Fig. 13b. In this case, when the dental tool 8 is inserted in the through opening 7, the outer diameter of the ring 11 increase. Simultaneously, the four solid parts (or teeth) 11c protruding in the through opening 7 and adjoining the indentations 7b elastically deform and due to the anisotropy of the dental tool 8. They partially flatten towards the upper and lower indentations 7b. As a consequence, the shape and the volume of the indentations 7b change.

[133] In the example of fig.12c, when the dental tool 8 is inserted in the through opening 7, the outer diameter of the ring 11 doesn’t necessarily increase, because the six solid parts 11c protruding in the through opening 7 and adjoining the indentations 7b partially flatten and/or bend towards the upper and lower indentations 7b forming a central opening 7a wide enough for the dental tool 8.

[134] Depending on the size, number and relative positions of the indentations 7b, the indentation can flatten and/or bend and/or the ring 11 can elastically be deformed when a dental tool 8 is inserted in the through opening 7.

[135] In a particular embodiment, the teeth 11 can be deformed along one or more directions orthogonal to the main axis of the through opening 7.

[136] In a particular embodiment, the teeth 11 can be deformed along the main axis of the through opening 7.

[137] In a particular embodiment, even when the teeth 11c adjoining the indentations 7b flatten and/or bend as much as possible along the inner surface of the ring 11 , at least two consecutive teeth 11c may not be in contact with each another.

[138] In a particular embodiment, one or more teeth 11c can be elastically deformed so that its external surface comes at least partially in contact with another part of the holding system 3, for example the inner surface of a ring 11.

[139] The number, the positions and the size of the indentations 7b and of teeth 11c may be chosen so that the shield 1 can be mounted on any dental tool of a given range of dental tools 8.

[140] The through opening 7 may for example comprise four, six or eight indentations 7b regularly spaced along the inside surface of the ring 11.

[141] In a particular embodiment, the teeth 11c adjoining the indentations 11c of the through opening 7 are made of the same material of another part of the holding system 3. In this case, the teeth 11c may have a lower Young’s modulus than the rest of the holding system 3. [142] In one embodiment, the teeth 11c are integral with the rest of the holding system 3. In this case, the holding system can be molded or 3D-printed.

[143] Alternatively, the teeth 11c are made of another material than the rest of the holding system 3.

[144] The teeth 11c allow the shield 1 to adapt to a wide variety of shapes and a wide range of characteristic sizes of a unique dental tool 8, and of different dental tools 8.

[145] For example, a part of a dental tool 8 having a rectangular section can without difficulty be equipped with a shield 1 in the embodiment of Fig. 12a. In this case, the deformation of the ring 11 will be anisotropic and all the teeth 11c won’t all bend and/or deform in the same manner.

[146] The profile of a tooth 11c in a plane orthogonal to the axis of the through opening 7 can be for example rectangular, ogival or partially circular.

[147] In case the holding system 3 comprises teeth 11c, once a dental tool 8 is inserted in the through opening 7, the dental tool may not be retained by the holding system 3 in a perfectly sealed manner since the contact surface between the dental tool 8 and the holding system may be discontinuous. However, if the characteristic dimensions of the indentations 7b and of the teeth 11c may be chosen so that the risk of water drops or spray passing from the patient-side of the dental shield 1 to the other side is very limited.

[148] Other various embodiments are provided for the retention system. These various embodiments are compatible with the description above.

[149] According to one embodiment, the retention system 10 is a mechanical retention system. This system comprises shapes which interact with complementary shapes of the dental tool to hold the dental tool 8 and the shield 1 together. For example, the dental tool 8 is mechanically locked on the shield 1 so as to prevent any relative movement of the dental tool 8 and the shield 1 until unlocking.

[150] According to yet one another embodiment, the retention system 10 is a magnetic retention system if the dental tool 8 comprises ferric components which can be subject to magnetic forces. For example, the retention system 10 comprises one magnet, which cooperates with the dental tool 8 to retain the dental tool 8 on the shield 1. The magnetic retention force might be overcome by hand, which enables to move the dental tool 8 with respect to the shield 1 as needed [151] A dental tool 8 can be equipped either with the shield 1 or with the holding system 3 on its own. Fig. 5 shows a typical dental tool 8 suitable for the invention. The dental tool 8 shown on Fig. 5 is a dental turbine. The dental turbine has an elongated shape along a main axis. It comprises an effective end 20 to be inserted into the mouth of the patient. The dental tool 8 comprises a handpiece 22, and a working insert 21 removably attached to the handpiece.

[152] As shown here, the working insert may have a longitudinal axis which is substantially angled with respect to the longitudinal angle of the handpiece, for example by 90°, 120° or more. The handpiece 22 may have a handling area 23, which is shaped to be held by the hand of the dentist. The handling area 23 may thus typically have a polygonal cross-section with respect to the longitudinal axis, or flat areas for the reception of fingers. The handling area 23 is close to the working insert 21. The handpiece 22 may also comprise a rear-end area with a different shape, for example with a cylindrical shape with a round cross-section.

[153] The shield 1 may be a single-use product. In such case, it could be manufactured by a simple manufacturing method, and with cheap components, so as to enable to manufacture a high number of products at lower cost.

[154] Alternately, the shield 1 on its whole may be a reusable product. In this case, the shield 1 can be decontaminated after use, for example through sterilization at the dental practice. In such case, material must resist autoclave temperature, typically above 121 °C, or even above 134°C.

[155] The product which has just been described can be used as follows.

[156] In the dental clinic, the patient is sitting in a conventional dental chair.

[157] The dentist assembles the dental tool 8 to the shield 1. This involves inserting the dental tool 8 through the shield 1, in particular through the through opening 7. In the above embodiment, this involves the dental tool 8 deforming the annular ring 11 of elastomeric material. The dental tool 8 is inserted so that its active end projects a few centimeters from the shield 1. The dental tool 8 is retained on the shield 1 in this position by the retention system 10. In particular, the elastomeric ring compresses the dental tool 8.

[158] In particular, the above description applies to the handpiece of the dental tool. Then, the working insert 21 is assembled to the handpiece after the handpiece was fixed on the shield 1. This is especially true if the working insert is sharp and angled, and there would be a risk of deteriorating the shield when passing the working insert through it. [159] The dentist will hold the dental tool 8 on the patient-side of the shield, by passing his/her hand below the shield 1 , and holding the dental tool 8 at the handling area 23 in a usual way. Therefore, the shield is positioned, along the shaft of the dental tool, so that sufficient space is available to the dentist to place his/her hand below the shield 1 , between the shield 1 and the face of the patient. If necessary, the relative position of the shield and the dental tool may be adjusted by applying a relative movement of the shield 1 and the dental tool 8 while the elastomeric ring is compressed. The dentist may also position his/her hand on the dentist-side of the shield 1 , holding the dental tool 8 at a distance of the handling area.

[160] The dentist moves the dental tool 8 to the mouth of the patient, and operates as usual. The sheet 2 covers the mouth of the patient at a few centimeters distance. The dentist can see inside the mouth of the patient as usual through the translucent sheet, or almost as usual, if the ring is not provided translucent. Sprays, spatters or splashes from the mouth of the patient will be blocked by the shield, in particular by the sheet, and are not ejected meters away. The splashes will flow on the patient-side surface 6b of the sheet 2, and fall back on the patient (or a bib covering the patient). According to some examples, the sheet 2 may be provided with a groove 24 or furrow on the patient-side, such as shown on the example of Fig. 3. Drops will flow on the patient-side surface 6b into the groove 24, then in the groove 24 to a designed exit. One or more grooves may be provided.

[161] If necessary, the dental tool 8 is moved and, with it, the shield 1 is moved as well. In active position, the distance of the shield 1 to the face of the patient may be sufficient so to limit contact with the nose or other parts of the face. If necessary, the sheet 2 can be deformed so that it adopts another stable configuration (or conformation). Also, if necessary, a relative movement may be applied to the shield 1 and the dental tool 8. The relative movement may be an axial translation along the shaft of the dental tool 8, or a rotation of the shield 1 about the longitudinal axis of the dental tool 8.

[162] When the dentist is done with the dental tool 8, it is withdrawn away from the mouth of the patient, and held stored on a dental unit. It is possible that the dentist will use this dental tool 8 again with this same patient. In such case, the shield 1 remains assembled to the dental tool 8. The dentist may change the working insert if necessary.

[163] For example, the other dental tool 8’ is a dental scaler or a dental sandblaster, an implant handpiece, a dental air-flow handpiece, a straight dental handpiece, etc. The tools could be surgical, implant or any kind of dental handpieces creating a spray. The other dental tool 8’ may be an aspiration device.

[164] According to the invention, it is therefore provided a set of shields 1, T, as described above, which differ in the way they cooperate with the dental tool.

[165] It is possible that the set of shields 1 comprises a limited number of different shields, each shield 1 being suitable for cooperating with a range of dental tools having a range of external diameters. For example, one could provide three different shields 1 , respectively for thin, medium, and large dental tools.

[166] As described above, if the dentist wishes to use simultaneously two dental tools 8, it is possible to assemble each dental tool 8 to a respective shield, and to use the two dental tools 8 at the same time. The sheet 2 of one of the two dental tools might partly cover the other one.

[167] At some point of time, when the dentist considers he is done with a specific dental tool, or with the patient, the shield 1 is unassembled from the dental tool 8. The working insert might be removed from the handpiece before that.

[168] If the shield 1 is single-use, it can be discarded.

[169] Alternately, the shield 1 is decontaminated using a suitable decontamination process. The shield 1 might be submitted to the same decontamination process as the dental tool 8 and/or the working insert itself.

[170] In case the holding system 3 is a two-part system, for use, the inner device 18 and the outer device 17 are assembled to one another using the attachment system 16 to form the shield 1. The shield 1 is used as discussed above. After use, the inner device 18 is disassembled from the outer device 17 using the attachment system 16.

[171] According to one example, the outer device 17 might be single-use, and discarded after use. The inner device 18 might be decontaminated/sterilized for further uses.

[172] According to this embodiment, different inner devices 18 might be provided, suitable to interact with different dental tools 8 as discussed above. Different inner devices 18 might be assembled to a same outer device 17. Further, different outer devices could be provided, which may be assembled to a same inner device 18. The different outer devices may for example differ by the size or shape of the sheet 2.

[173] LIST OF THE REFERENCE SIGNS : Shield 2 : Sheet

3 : Holding system

4 : Main body of the sheet 2

5 : through opening of the sheet 32 6a, 6b : Surfaces 7 : through opening of the holding system 3

7a : central opening of the through opening 7 7b : indentation, part of the through opening 7

8 : Dental tool

9 : Attachment portion of the holding system 3 to the sheet 2 10 : Retention system of the holding system 3

11 : Ring

11b : groove formed in a ring 11 11c : solid part (or tooth) adjoining an indentation 7b 12: Outer ring surface 13 : Inner ring surface 14 : Outer part 15 : Inner part

16 : Attachment system between the inner part 14 and the outer part 15 17: Outer device of the shield 1

18 : Inner device of the shield 1

19 : Edges 20 : Effective end of the dental tool 8 21 : Working insert of the dental tool 8

22 : Handpiece of the dental tool 8

23 : Handling area of the dental tool 8