WO2010088754A1

WO2010088754A1 - Connector for mounting an asymmetric abutment to a dental implant

Info

Publication number: WO2010088754A1
Application number: PCT/CA2009/001897
Authority: WO
Inventors: Jean Robichaud
Original assignee: Biocad Médical Inc.
Priority date: 2009-02-05
Filing date: 2009-12-29
Publication date: 2010-08-12

Abstract

A male-male connector is disclosed for mounting an abutment to a dental implant. The male-male connector comprises first male connecting means extending in a first direction for engaging the dental implant. The male-male connector further comprises second male connecting means extending in a second direction opposite to the first direction for engaging a corresponding female connecting portion located inside a bottom portion of the abutment. The second male connecting means comprises at least one anti-rotational element adapted for mating with second positioning means on the female connecting portion of the abutment. The at least one anti-rotational element and the second positioning means have substantially complementary shapes. In preferred embodiments, the complementary shapes of the least one anti-rotational element and the second positioning means is such that only one rotational alignment position is possible between the male-male connector and the asymmetric abutment. Also described are attachments for securing a prosthetic crown to a dental implant, kits and prosthetic teeth comprising a male-male connector or and attachment described herein, and also methods for manufacturing an asymmetric abutment for installation in a unique position in a patient's mouth.

Description

CONNECTOR FOR MOUNTING AN ASYMMETRIC ABUTMENT TO A DENTAL

IMPLANT

FIELD OF THE INVENTION

[0001] The invention relates to an artificial tooth. More precisely, this invention pertains to a connector for mounting an asymmetric abutment to a dental implant.

BACKGROUND OF THE INVENTION

[0002] Artificial and prosthetic teeth are a common solution for tooth loss resulting from trauma, decay, gum disease or ageing. Typically, prosthetic teeth are installed with a procedure involving the drilling of a hole in the patient's jawbone and the insertion of a metallic (e.g. titanium) dental implant. A standard or customized abutment is then usually mounted on the dental implant. Standard abutments are generally symmetric whereas customized abutments are generally asymmetric. A prosthetic crown having the shape of a tooth is then placed on top of the abutment.

[0003] In the restoration procedure, the main difficulty still lies in the positioning of each prosthetic tooth relative to an already installed dental implant to provide the patient with a set of perfectly aligned teeth. Another difficulty is to manufacture an abutment that resists to stresses.

[0004] One of the problems which lie with the current artificial teeth is that the abutment generally requires a narrow connector for attachment to the dental implant integral to the base of the abutment. The abutment and its connector being made of the same material (example: zirconia), such connectors are subject to fracture when under stress, e.g. when load is applied during mastication. Broken connectors are extremely difficult to replace and their replacement causes discomfort and anguish to patients.

[0005] Among the solutions currently being explored is the manufacturing of artificial teeth further comprising a separate connector located between the abutment and the dental implant. Examples of known connectors can be found in US Patent No.

7,393,210; US Patent No. 5,006,068; US Patent No. 5,733,124; US Patent No.

5,281 ,140; US Patent No. RE37.227; US Patent No. 6,168,435; US Patent No.

RE37.227; and US Patent Publication US 2004/0076924. Although such a connector provides some benefits in improving stress resistance, fractures are still common especially with those connectors in which a screw is seated inside the abutment. In addition, the positioning and rotational alignment of the connector with the abutment, as well as the alignment of the abutment with the dental implant, is still difficult. Indeed, since a person has to secure the abutment with its connector by hand, using an adhesive material, there is very little time to rotate or modify the position of the abutment with respect to the connector in order to get the abutment and the connector in the right alignment position with the dental implant. In the case where the abutment and the connector are secured directly in the patient's mouth, this procedure is even more difficult.

[0006] Positioning of a standard abutment in a dental implant is generally less of an issue because the abutment is symmetric. However, placing a customized abutment in its right position is much more difficult since the abutment is not symmetric around its longitudinal axis. When the customized abutment is manufactured separately from its connector, and the abutment and connector are possibly assembled in yet a subsequent step, the problem is even more complex since the abutment and the connector have to be properly aligned with each other such that the abutment is rotationally aligned with the dental implant for which it was designed, i.e. a dental implant having a specific rotational position relative to the jawbone or other teeth of the patient. Once the implant has been integrated to the osseous tissue of the jawbone it is impossible to move or rotate the implant. Therefore, each abutment has to be made or corrected individually which increases the complexity of the procedure. In the particular case of an abutment manufactured separately from its connector, if the abutment and the connector are assembled in mouth, correcting the position of the abutment with respect to the connector increases the complexity of the procedure and causes stress to patients.

[0007] Therefore, it would be desirable to provide artificial teeth that better resist pressure and are less likely to fracture. It would also be desirable to provide artificial teeth that are easier to position to increase the likelihood of obtaining a set of perfectly aligned teeth.

[0008] More particularly, there is a need for an abutment which is mounted onto a dental implant with less risk of fracture, and more particularly an asymmetric customized abutment.

[0009] There is also a need for an abutment with reduced risk of misalignment with respect to the dental implant. [00010] There is also a need for an attachment for securing a prosthetic crown to a dental implant, that attachment ensuring a perfect positioning and/or alignment of the abutment to the dental implant.

[00011] There is an additional need for methods of manufacturing asymmetric abutments for installation in a predefined position in a patient's mouth.

[00012] The present invention addresses these and other needs, as will be apparent from a review of the disclosure, drawings and description of the invention below.

BRIEF SUMMARY OF THE INVENTION

[00013] According to one aspect, the invention relates to a male-male connector for mounting an asymmetric abutment to a dental implant. As used herein the term "male- male connector" refers to a connector having at least two sections extending in opposite directions, one section being configured for fitting into the dental implant, one section configured being for fitting into the asymmetric abutment.

[00014] As used herein the term "asymmetric abutment" refers to an abutment which has an external surface and/or an external contour that is/are asymmetrical around the longitudinal axis of the abutment. Asymmetrical abutments include customized abutments which have either been machined or cast for a particular individual in order to obtain a desired external shape taking into consideration an exact position of installation in the mouth and an individual's gum condition and the rotational position of a dental implant. Generally, this term is used in opposition to the more standard "prefabricated" symmetric abutments.

[00015] In one embodiment the male-male connector comprises first male connecting means extending in a first direction for engaging the dental implant; second male connecting means extending in a second direction opposite to the first direction for engaging a corresponding female connecting portion located inside a bottom portion of the abutment. The second male connecting means comprises at least one anti-rotational element adapted for mating with second positioning means on the female connecting portion of the abutment. Advantageously, the at least one anti-rotational element and the second positioning means have substantially complementary shapes configured for providing between one (1) to eight (8) rotational alignment positions between the male- male connector and the asymmetric abutment. Preferably, the at least one anti-rotational element comprises first positioning means, and the first positioning means and the second positioning means have complementary shapes configured for providing only one rotational alignment position between the male-male connector and the asymmetric abutment.

[00016] In a preferred embodiment, the male-male connector comprises: - first male connecting means extending in a first direction for engaging the dental implant;

- second male connecting means extending in a second direction opposite to the first direction for engaging a corresponding female connecting portion located inside a bottom portion of said abutment, the second male connecting means comprising at least one anti-rotational element adapted for mating with second positioning means on the female connecting portion of the abutment, the at least one anti-rotational element and the second positioning means having substantially complementary shapes configured for providing between one (1) to eight (8) rotational alignment positions between the male-male connector and the asymmetric abutment; and

- a central bore extending throughout the first male connecting means and the second male connecting means, the central bore comprising a narrowing providing a seat for receiving a fastener and securing the fastener and the male- male connector to the dental implant.

[00017] According to another aspect, the invention relates to an attachment for securing a prosthetic crown to a dental implant. The attachment comprises a male-male connector comprising first male connecting means extending in a first direction for engaging the dental implant and second male connecting means extending in a second direction opposite to the first direction, the second male connecting means comprising at least one anti-rotational element. The attachment also comprises an asymmetric abutment for receiving the prosthetic crown thereon. The abutment has a bottom portion comprising a female connecting portion adapted for receiving therein the second male connecting means of the connector. The female connecting portion of the abutment comprises second positioning means adapted to mate with the at least one anti- rotational element of the connector.

[00018] In a preferred embodiment, the attachment comprises:

- a connector comprising: - first male connecting means extending in a first direction for engaging the dental implant; - second male connecting means extending in a second direction opposite to the first direction, for engaging a corresponding female connecting portion located inside a bottom portion of an asymmetric abutment, the second male connecting means comprising at least one anti-rotational element;

- an asymmetric abutment for receiving the prosthetic crown thereon, the abutment having a bottom portion comprising a female connecting portion adapted for receiving therein the second male connecting means of the connector.

[00019] The at least one anti-rotational element of the connector and the second positioning means of the abutment have complementary shapes configured for providing between one (1) to eight (8) rotational alignment positions between the male-male connector and the asymmetric abutment. According to additional aspects, the invention concerns methods for manufacturing an asymmetric abutment. The methods of the invention are particularly useful for the manufacture of asymmetric abutments for installation in a single predetermined rotational alignment position in a patient's mouth.

[00020] According to another aspect, the invention relates to a kit comprising an attachment or a connector as defined herein.

[00021] According to a further aspect, the invention relates to a prosthetic tooth comprising an attachment or a connector as defined herein.

[00022] According to another aspect, the invention relates to a method for installing a prosthetic tooth in the mouth of a patient. The method comprises securing to a dental implant located in the patient's jawbone an attachment or a connector as defined herein.

[00023] These and other objects, advantages and features of the present invention will become more apparent to those skilled in the art upon reading the details of the invention more fully set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS [00024] In order for the invention to be readily understood, embodiments of the invention are illustrated by way of examples in the accompanying drawings.

[00025] FIGURE 1 is an exploded, front perspective view of a prosthetic tooth for assembly in a jawbone. [00026] FIGURE 2 is an exploded, front perspective view of the prosthetic tooth assembly shown in Figure 1 , in accordance with one embodiment of the present invention.

[00027] FIGURE 3 is a front perspective view of an assembled prosthetic tooth in accordance with one embodiment of the present invention.

[00028] FIGURE 4 is a front perspective view of a connector and an abutment in accordance with one embodiment of the present invention.

[00029] FIGURE 5 is an exploded side perspective view of the connector and the abutment shown in Figure 4.

[00030] FIGURE 6 is a cross section view of prosthetic tooth assembly in accordance with one embodiment of the present invention.

[00031] FIGURES 7A and 7B are exploded perspective views of a connector and abutment in accordance with another embodiment of the invention, the connector having a concave shaped positioning means.

[00032] FIGURES 8A and 8B are exploded perspective views of a connector and abutment in accordance with another embodiment of the invention, the connector having a convex shaped positioning means.

[00033] FIGURES 9A and 9B are exploded perspective views of a connector and abutment in accordance with another embodiment of the invention, the connector having positioning means with a substantially triangular cross-section.

[00034] FIGURES 10 and 10B are exploded perspective views of a connector and abutment in accordance with another embodiment of the invention, the connector having convex shaped and concave shaped positioning means.

[00035] FIGURE 11 is an exploded side perspective view of the connector and the abutment in accordance with another embodiment wherein the abutment further comprises retention means with semi-circular grooves.

[00036] FIGURE 12 is a cross section view of the connector and the abutment in accordance with the embodiment shown in Figure 11. [00037] FIGURE 13 is a cross section view of the connector and the abutment in accordance with another embodiment wherein the abutment further comprises retention means having a triangular shape.

[00038] FIGURE 14 is a cross section view of the connector and the abutment in accordance with another embodiment wherein the abutment further comprises retention means having a pyramidal shape.

[00039] FIGURE 15 is a cross section view of the connector and the abutment in accordance with another embodiment wherein the abutment further comprises retention means having both a triangular and a square shape.

[00040] Further details of the invention and its advantages will be apparent from the detailed description included below.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[00041] In the following description of the embodiments, references to the accompanying drawings are made by way of illustration of examples by which the invention may be practiced. It will be understood that other embodiments may be made without departing from the scope of the invention disclosed.

Male-male connector

[00042] As it will be described hereinafter, embodiments of the invention generally relate to artificial and prosthetic teeth. As shown in Figure 1 , an artificial tooth according to the invention comprises a prosthetic crown 102 crafted according to a tooth to be replaced, a dental implant 104 to be inserted in the jaw 10 of a patient and an attachment 100 for securing the prosthetic crown 102 to the dental implant 104. The attachment 100 comprises an asymmetric abutment 106 for receiving thereon the prosthetic crown 102 and a connector 108 for connecting the abutment 106 to the dental implant 104. Preferably, a fastener 110 secures the asymmetric abutment 106 and the connector 108 to the implant 104.

[00043] Figures 2 to 10 show with more details miscellaneous embodiments of the abutment 106 and the connector 108 according to the invention.

[00044] The connector 108 comprises first male connecting means 206 extending in a first direction for engaging an upper recess 204 of the dental implant 104; second male connecting means 208 extending in a second direction opposite to the first direction for engaging the abutment 106; and a seat element 210 providing a seating surface 211 to receive thereon the abutment 106. In the illustrated embodiment the seat element 210 has a circumferential disk-like shape and is located between the first and second connecting means and projecting substantially perpendicularly away from the first connecting means and the second connecting means.

[00045] In some embodiments, where a fastener 110 is used, the connector 108 is further provided with a central bore 207 for receiving therein the fastener 110. As best shown in Figure 6, the second male connecting means 208 preferably comprises a shoulder 615, such as formed by a narrowing of the central bore 207. The shoulder 615 thus provides a seat for receiving the fastener (e.g. head 610 of the screw 614) and securing the connector 108 to the implant 104. Having a seat inside the connector 108 is advantageous compared to other types of connectors where a seat for the fastener is provided by the abutment. Because the fastener is not in direct contact with the abutment, the connector according to the invention and its seat inside reduce the pressure stress to the abutment, thereby minimizing risk of fracture of the abutment.

[00046] Preferably, the first male connecting means 206, the second male connecting means 208 and the seat element 210 are a monolithic structure. Thus, the connector 108 can be manufactured from a single block of material, or molded, to attain the previously described configuration. The connector 108 can be made of titanium, alloys such as cobalt-chrome, precious alloys such as gold or platinum or any other material that possesses qualities one skilled in the art might consider useful or appropriate for obtaining a connector resistant to stresses such as the ones produced during the mastication. In a preferred embodiment, the connector 108 is manufactured from a block of titanium, such as dental grade titanium, for example commercially pure titanium or titanium alloy.

[00047] As best shown in Figure 4, in one embodiment the first male connecting means 206 comprises one or more anti-rotational features for connection with the upper recess 204 of the dental implant. In the illustrated embodiment the anti-rotational feature comprises a projection protruding downwardly from the seat element 210, such as a hexagonal projection having six lateral faces 205 and six edges 209. As shown in Figure 2, the upper recess 204 of the dental implant 104 and the first male connecting means 206 have complementary mating shapes ensuring a substantially tight fit. In this embodiment, the six lateral faces 205 and six edges 209 of the anti-rotational feature provide six (6) different possibilities for positioning the connector 108 over the implant 104. Although not illustrated, those skilled in the art will appreciate that the anti-rotational feature may have different shapes, according to different possible substantially complementary shapes for the first male connecting means 206 and the upper recess 204. Additional examples of substantially complementary shapes include, but are not limited to, an hexagonal shape, a triangular shape, a rectangular shape, an octagonal shape, a cross shape, a semi-circular, a star shape, or any other suitable complementary shape preventing rotation of the connector 108 once engaged in the upper recess 204 of the dental implant 104. However, as it will become more apparent hereinafter, the shape of the first male connecting means should also provide a limited number of predetermined possible positions for engaging the connector to the dental implant, preferably eight (8) or less, such that a practitioner (e.g. dentist) can easily and quickly identify the proper position for the connector, i.e. identify the right rotational alignment of the connector with the implant.

[00048] Moving again to Figure 4, in the illustrated embodiment the second male connecting means 208 is a hollow cylinder 400 extending upwardly from the seat element 210 in an opposite direction from the first male connecting means 206. The hollow cylinder 400 has an external surface comprising at least one groove. In the illustrated embodiment a plurality of optional but preferable substantially parallel spaced- apart grooves 408 are provided. The grooves 408 provide an empty volume to be filled by an adhesive material (e.g. glue, cement) when assembling the abutment 106 onto the connector 108 (see Figure 6). In this embodiment the grooves 408 are substantially parallel to the seating surface 211 and extending around the circumference of the external surface. However, many additional types of patterns and orientations are conceivable, including but not limited to angled grooves, wave-shaped grooves, grooves defining a mesh-like pattern, plurality of recesses defining a dotted-like surface, etc. In the preferred embodiment illustrated, the grooves 408 are registered with corresponding grooves 1110 carved in the abutment 106 as best shown in Figure 12. The grooves 408 of the connector and the grooves 1110 of the abutment 106 may be axially aligned when the connector is mounted to the abutment 106. The external surface of the hollow cylinder 400 could also be rough or have any other pattern improving retention of the adhesive material. The external surface of the hollow cylinder 400 could also be smooth and the second male connecting means 208 could be secured to the abutment 106 by another method, such as a press fit method, the first and second male connecting means being aligned with each other.

[00049] As best shown in Figure 5, the second male connecting means 208 further comprises at least one anti-rotational element 430 adapted to mate with a central fastening hole 450 in the abutment 106. The at least one anti-rotational element 430 is configured for preventing rotation of the abutment 106 when engaged to the connector 108. The at least one anti-rotational element is also configured for providing a limited number of possible rotational positions when engaging the abutment 106 to the connector 108. Although not illustrated, those skilled in the art will appreciate that the at least one anti-rotational element, the second male connecting means 208 and the central fastening hole 450 may have various complementary shapes. In the illustrated preferred embodiment, the at least one anti-rotational element 430 serves as a first positioning means adapted to mate with a corresponding second positioning means 475 of the abutment 106. The first positioning means 430 and the second positioning means 475 are operatively configured for providing only one rotational alignment position between the male-male connector 108 and the abutment 106. Accordingly, the first positioning means 430 and the second positioning means 475 have complimentary shapes for preventing rotation of the connector 108 inside the abutment 106. In the embodiment shown in Figure 5, the first positioning means is a flat rectangular surface 431 crafted at the external surface of the hollow cylinder 400.

[00050] Referring now to the abutment 106 and to Figures 4 and 5, the abutment 106 comprises a generally conical top portion 212 and a generally obconical, trumpet-shaped bottom portion 214. The principal role of the conical top portion 212 is to receive thereon the prosthetic crown 102 whereas the principal role of the bottom portion 214 is to go inside the gum of a patient (see Figure 6) to have a natural emergence profile allowing proper contouring of the restoration, and also to operatively connect the second male connecting means 208 of the connector 108. The illustrated abutment 106 further comprises a central fastening hole 450 extending therethrough for passing therein a fastener 110 (see Figs. 2 and 6).

[00051] In the illustrated embodiments shown in the figures, the conical top portion 212 has an external surface 460 and an upper truncated end 462 with three top slanted faces 464. The external surface 460 comprises a trumpet-shaped bottom ending 468 joining the bottom portion 214 at peripheral wavy edge 472. The shape of the external surfaces of the top 212 and bottom 214 portions of the abutment 106 illustrated herein is conventional to what is commonly used in the industry. The invention is not limited to that specific shape and those skilled in the art will appreciate that the external surfaces of the top 212 and bottom 214 portions of the abutment 106 may have different shapes other that the one illustrated in the present embodiment. For instance, the truncated end 462 could have more or less than three faces (1 , 2, 4, etc.) and the top slanted faces 464 could be curved surfaces. The angles of the top slanted faces 464 of the upper truncated end 462 may also be different. The bottom portion 214 comprises a trumpet-shaped external surface 486 meeting the trumpet-shaped bottom ending 468 of the conical top portion 212 at peripheral wavy edge 472.

[00052] Referring more particularly to Figures 4 and 5, it can be appreciated that the abutment 106 is asymmetrical because the peripheral wavy edge 472 defines a contour which is not equally distanced from the external surface 460 of the top portion 212, nor equally distanced from the bottom annular surface 574. Accordingly, both the trumpet- shaped ending 468 of the conical top portion 212 and the trumpet-shaped external surface 486 of the bottom portion 214 are similarly wavy and asymmetrical.

[00053] As shown in Figure 5, the central fastening hole 450 of the bottom portion 214 serves, among other things, as female connecting portion and is adapted for receiving the second male connecting means 208 of the connector 108. Accordingly, the bottom portion 214 also comprises a bottom annular surface 574 configured to fit with the seat element 210 of the connector 108. The bottom portion 214 comprises an interior surface 476 having a section comprising the second connecting means 475 which is configured to complement the first positioning means 430 of the connector 108. In the embodiment illustrated in Figure 5, the second positioning means 475 comprises a slight embossment 477 protruding from the interior surface 476, the embossment 477 mating with the first positioning means 430 illustrated on Figure 5 as a flat rectangular surface 431 crafted at the external surface of connector 108.

[00054] Those skilled in the art will appreciate that the invention may comprise more than one pair of first and second positioning means and that the positioning means may have various complementary shapes and may be irregularly spaced around the connector or the abutment. When irregularly spaced, the first and second positioning means may improve anti-rotation fixation but yet a single rotational position is provided. For instance, in a second embodiment illustrated at Figures 7A and 7B, the first positioning means 430 comprises a semi-circular concave groove 731 and the second positioning means 475 comprises a semi-circular convex embossment 777 at the interior surface 476 of the bottom portion 214. In a third embodiment illustrated at Figures 8A and 8B, the first positioning means 430 comprises a semi-circular convex embossment 831 and the second positioning means 475 comprises a semi-circular concave groove 877 at the interior surface 476 of the bottom portion 214. In a fourth embodiment illustrated at Figures 9A and 9B, the first positioning means 430 comprises an embossment 931 having a substantially triangular cross-section and the second positioning means 475 comprises a triangular concave shaped groove 977 at the interior surface 476 of the bottom portion 214. In a fifth embodiment illustrated at Figures 1OA and 1OB, the first positioning means 430 comprise a combination of two different elements and comprises both, a semi-circular convex embossment 831 and a semi- circular concave groove 731 , and the second positioning means 475 comprise corresponding semi-circular concave shaped groove 877 and a semi-circular convex embossment 777, both on the interior surface. The present invention encompasses these illustrated shapes, other functional equivalents and any suitable combination thereof.

[00055] The conical top portion 212 and the bottom portion 214 preferably define an integral structure. The abutment 106 can be manufactured from a unique block of material to attain the previously described configuration. In one preferred embodiment, the abutment 106 is manufactured from a block of zirconium. The material for manufacturing the abutment 106 may also be selected amongst titanium, ceramic, cobalt-chrome alloy, composite materials, or any other material that possesses qualities one skilled in the art might consider useful or appropriate for this purpose.

Assembly of a prosthetic tooth

[00056] Having described the main elements composing the invention, its assembly in a complete prosthetic tooth will now be described with reference to Figures 1 and 2.

[00057] To secure the abutment 106 with the connector 108, the abutment 106 is positioned over then lowered onto the connector 108. As described hereinbefore, a perfect positioning of the abutment 106 over the connector 108 (and so over the dental implant 104) is achieved with minimum efforts and skills thanks to the configuration of the abutment 106 and the connector 108, and more particularly to the complementary shapes of the first positioning means 430 (i.e. the at least one anti-rotational element) of the connector 108 and the second positioning means 475 inside the bottom portion of the abutment 106. Mating the first 430 and second positioning means 475 ensures the correct rotational alignment of the abutment 106 to both the connector 108 and the implant 104. Typically, an adhesive is then used to permanently secure the abutment 106 to the connector 108.

[00058] To secure the connector 108 with the dental implant 104 the connector 108 is positioned over then lowered onto the dental implant 108 such that the seat element 210 of the connector 108 sits on top of the dental implant 104. Because of the configuration of the first male connecting means 206 of the connector 108 and the complementary configuration of the recess 204 in the dental implant 104, that step requires minimum skills and a perfect alignment is easily provided.

[00059] According to a first method of installation in a patient's mouth, the abutment 106 is first secured with the connector 108 and then, once the dental implant 104 is installed in the jaw 10 of a patient, the connector 108 (with the abutment 106 on it) is secured with the dental implant 104. The abutment 106 can be secured with the connector 108 before installing the dental implant 104 or after the dental implant 104 has been installed.

[00060] According to a second method of installation in a patient's mouth, the connector 108 is first secured with a dental implant 104 already installed into the jaw 10 of a patient, and then the abutment 106 is secured with the connector 108, directly in the patient's mouth.

[00061] A fastener 110 (e.g. a screw) is then inserted through the abutment 106 for fastening the connector 108 to the dental implant 104. As best shown in Figure 6, according to this particular embodiment, the fastener 110 is a screw comprising a head 610 and a shaft 612, the shaft being provided with a threaded portion 614 for engaging corresponding thread in the implant 104. Once in a proper position, the head 610 of the fastener 110 lies on a bottom surface inside the connector 108, thereby preventing any undesirable movement or removal of the connector 108 from the implant 104. However, the invention is not limited to the use of a fastener since the abutment 106 could eventually rather be secured in the implant 104 by using other means (e.g. by cementing the lower portion 214 of the abutment 106 to connector 108, by cementing also the connector 108 to the implant 104).

[00062] As shown also in Figure 6, once in a proper final position, the connector 108 is secured to the dental implant 104 located in the patient's jawbone 10. The depth at which a dental implant 104 is placed in the jawbone depends on the gum's width, so it is possible that a part of the dental implant 104 be in the gum 20. The abutment 106 is secured to the connector 108. Preferably, the abutment 106 is designed to ensure that at least part of its bottom portion 214 is under the gum 20, and most preferably entirely under the gum 20, the upper portion 212 being outside the gum 20. Alternatively, when the dental implant 104 is located deeply in the bone 10, it is possible that a section of the bottom portion 214 be located in the bone 10. Finally, the central fastening hole 450 is generally filled (e.g. a piece of cotton and a composite material) and the crown 102 is cemented over the upper portion 212 of the abutment 106. [00063] Now referring to Figures 11 to 15, according to some embodiments, the interior surface 476 of the bottom portion 214 of the abutment 106 comprises retention means 1100. The purpose of the retention means 1100 is to provide a free or empty volume to be filled with an adhesive material (e.g. cement, glue or the like) when fixing the abutment 106 over the second male connecting means 208 of the connector 108. Once the adhesive material has solidified it provides, with the retention means 1100 and the second male connecting means 208 of the connector 108, stronger mechanical retention means.

[00064] The retention means 1100 may be carved or crafted into the bottom portion 214 of the abutment 106. The skilled addressee will appreciate that the invention is not limited to a particular type of retention means 1100 since it may be of various sizes and have different shapes. For instance, it may be semi-circular (see for instance the grooves 1110 on Figures 11 and 12), triangular (see for instance 1310 on Figure 13 or 1520 on Figure 15), pyramidal (see for instance 1410 on Figure 14), square or rectangular (see for instance 1510 on Figure 15), it may be a mesh-like pattern (not shown), or it may be a combination of those (see for instance 1510 and 1520 on Figure 15). The retention means 1100 may be present only on a limited portion of the interior surface 476 of bottom portion 214 or extend over the entire surface thereof.

Custom manufacturing [00065] Practitioners know that the assembling process is generally the same no matter what method is used to design a customized abutment, i.e. by hand or by using computer software. Practitioners also know that, for the prosthetic tooth to be properly aligned in the patient's mouth, each asymmetric abutment 106 has to be designed individually by considering its positioning relative to the connector 108, and by considering also the positioning of the connector 108 relative to the dental implant 104. These considerations have to be taken into account, no matter what method is used to design the customized abutment.

[00066] In one particular embodiment, the shape of the asymmetric abutment is designed by using computer-aided design software and a computer model of a jaw of a patient showing the spatial position and orientation of the implant into the jaw. For instance, once the dental implants have been installed, a plaster model of the patient's jaw is created then scanned, e.g. by using an optical scanner in order to obtain a computer model of the patient's jaw and at least a portion of the implants. The scan information is used to create a virtual computer model of the jaw and implants showing the positions, such as rotational and angular positions, of the implants in the jaw of the patient. Then, the computer model on which the implants positions are visible is then transferred to a computer-aided design (CAD) software to design the abutment. Alternatively, the model of the jaw and implant are created in the CAD software.

[00067] For instance, for a given dental implant, a CAD user imports into the software a 3D representation of the connector 108 and selects arbitrarily a desired rotational alignment position of the connector 108 with respect with the implant 104 (e.g. one of the six possible positions for an implant having a hexagonal shaped recess 204 as illustrated herein). Selecting the desired rotational position for the connector 108 automatically fixes into the 3D space a spatial position and rotational orientation for the first positioning means 430 of the connector 108. The CAD user then designs a customized abutment 106 having a desired asymmetrical shape of the external surface and comprising second positioning means 475 complementary to the first positioning means 430 of the connector 108. The rotational position of the first positioning means 430 of the connector is selected such that the rotational position of the second positioning means 475 is positioned in a desired rotational position relative the external surface of the abutment. For example, it might be desired to position the second positioning means substantially buccally, lingually, or mesially. The CAD user shapes the external surface of the customized abutment 106 and positions the second positioning means 475 considering the exact position of the first positioning means 430 for obtaining the right rotational alignment of the abutment to both the connector and the implant.

[00068] The CAD software may be used for helping in determining a proper shape of the interior surface of the bottom portion of the abutment and the software may be set such that this shape remains constant such that the CAD user can only manipulate the exterior surface of the abutment. Finally, using known computer-aided manufacturing technology and the computer model of the abutment(s) which has(have) been created, a machine manufactures the desired abutment(s).

[00069] Therefore, as defined hereinbefore, additional aspects of the invention concern methods for manufacturing an asymmetric abutment. The methods are useful for manufacturing asymmetric abutments (e.g. a customized abutment) for installation in a patient's mouth. In one embodiment the method comprises providing a three- dimensional computer model of a connector to be mounted on an implant positioned in the mouth of the patient, the connector comprising first positioning means; and creating a three-dimensional computer model of the asymmetric abutment to be manufactured, wherein the asymmetric abutment comprises second positioning means configured to fit with the first positioning means of the connector. [00070] Preferably the three-dimensional computer model of the asymmetric abutment is created for installation in a single predetermined rotational alignment of the abutment to the connector. Therefore, in preferred embodiments, the first positioning means and the second positioning means have substantially complementary shapes and the second positioning means is positioned on the abutment for providing a single predetermined rotational alignment of the abutment to the connector. In the manufacturing method, the first positioning means may be used as a point of reference for identifying the single predetermined rotational alignment of the abutment to the connector.

[00071] According to another embodiment the method comprises:

- providing a three-dimensional computer model showing an implant position in the patient' mouth;

- providing a three-dimensional computer model of a connector adapted for mounting the asymmetric abutment to the implant, the connector comprising: first connecting means extending in a first direction for engaging an upper recess of the dental implant; and second connecting means extending in an opposite direction from the first connecting means, the second connecting means comprising first positioning means adapted for mating with second positioning means inside a bottom portion of the asymmetric abutment to be mounted in the patient's mouth;

- creating a three-dimensional computer model of the asymmetric abutment to be manufactured, wherein the asymmetric abutment has a shape defined for a predetermined rotational position alignment relative to the rotational position of the dental implant; and

- determining the rotational position of the second positioning means relative to an outer surface of the asymmetric abutment.

[00072] Generally, the first positioning means provides a point of reference for identifying the predetermined rotational position alignment. In preferred embodiments, the connector is a male-male connector.

[00073] Additional steps may comprise machine manufacturing the asymmetric abutment by using the three-dimensional computer model of the asymmetric abutment using the three-dimensional computer model thus created. [00074] Therefore, one can appreciate that the invention provides numerous advantages. Indeed, it is possible by using a connector according to the invention to minimize risks of fracture of abutments mounted onto dental implants. Because of its configuration requiring a combination of an adhesive material and a fastener, and the presence of one or more anti-rotational feature(s), the connector of the invention and asymmetric abutment can be delivered separately without risking misaligning or installing of the abutment in a wrong position.

[00075] The invention also provides means for improving manufacturing in two different pieces, asymmetric abutments and connectors. This allows the use of two different materials for the abutment and connector thereby permitting the use for connectors of materials more resistant to stress than the material commonly used for abutments.

[00076] The invention also provides an abutment and a connector that are easy to position with respect to each other and also easy to position during installation onto a dental implant. Therefore, a person securing the abutment with the connector is no longer required to rush because of the setting time of the dental adhesive since the pieces just fit into each other into the right position. The probability of making a mistake is thus reduced. In cases where practitioners (e.g. dentists) secure the abutment with the connector directly in the mouth of the patient, this represents much less stress and much less discomfort for the patient.

[00077] Although the above description relates to a specific preferred embodiment as presently contemplated by the inventor, it will be understood that the invention in its broad aspect includes mechanical and functional equivalents of the elements described herein.

Claims

CLAIMS:

1. A male-male connector for mounting an asymmetric abutment to a dental implant, said male-male connector comprising: - first male connecting means extending in a first direction for engaging said dental implant; and

- second male connecting means extending in a second direction opposite to the first direction for engaging a corresponding female connecting portion located inside a bottom portion of said abutment, said second male connecting means comprising at least one anti-rotational element adapted for mating with second positioning means on the female connecting portion of the abutment.

2. The male-male connector of claim 1 , wherein said at least one anti-rotational element comprises first positioning means, and wherein the first positioning means and the second positioning means have complementary shapes configured for providing only one rotational alignment position between the male-male connector and the asymmetric abutment.

3. The male-male connector of claim 1 or 2, wherein the connector comprises a central bore extending throughout the first male connecting means and the second male connecting means, said bore being configured for receiving a fastener and securing the male-male connector to the dental implant.

4. The male-male connector of claim 3, wherein the central bore is provided with a shoulder for receiving the fastener.

5. The male-male connector of claim 4, wherein the shoulder is formed by a narrowing of the central bore.

6. The male-male connector of any one of claims 1 to 5, wherein the first male connecting means comprises one or more anti-rotational features for connection with a corresponding number of anti-rotational features with complementary shapes of an upper recess in an upper portion of the dental implant.

7. The male-male connector of claim 6, wherein the first male connecting means and the upper recess comprises substantially complementary mating shapes providing a predetermined number of possible positions for engaging the connector to the dental implant.

8. The male-male connector of any one of claims 1 to 7, wherein the connector further comprises a circumferential disk-shaped seat element located between the first and second connecting means and projecting perpendicularly away therefrom.

9. The male-male connector of claim 8, wherein said substantially complementary mating shapes are selected from the group consisting of an hexagonal shape, a triangular shape, a rectangular shape, an octagonal shape, a cross shape, a semicircular shape, and a star shape.

10. The male-male connector of any one of claims 1 to 9, wherein the second male connecting means comprises an external surface with at least one recess, the recess providing an empty volume to be filled by an adhesive material.

11. The male-male connector of claim 10, wherein the external surface comprises a plurality of spaced-apart substantially parallel grooves.

12. The male-male connector of any one of claims 1 to 11 , wherein said connector is made of a material selected from the group consisting of: titanium, cobalt-chrome, gold and platinum.

13. The male-male connector of claim 1 , wherein said at least one anti-rotational element and said second positioning means have substantially complementary shapes configured for providing from one (1) to eight (8) rotational alignment positions between the male-male connector and the asymmetric abutment.

14. A male-male connector for mounting an asymmetric abutment to a dental implant, said male-male connector comprising:

- first male connecting means extending in a first direction for engaging said dental implant;

- second male connecting means extending in a second direction opposite to the first direction for engaging a corresponding female connecting portion located inside a bottom portion of said abutment, said second male connecting means comprising at least one anti-rotational element adapted for mating with second positioning means on the female connecting portion of the abutment, said at least one anti-rotational element and said second positioning means having substantially complementary shapes configured for providing between one (1) to eight (8) rotational alignment positions between the male-male connector and the asymmetric abutment; and - a central bore extending throughout the first male connecting means and the second male connecting means, the central bore comprising a narrowing providing a seat for receiving a fastener and securing said fastener and the male- male connector to the dental implant.

15. The male-male connector of claim 14, wherein said at least one anti-rotational element comprises first positioning means, and wherein the first positioning means and the second positioning means have complementary shapes configured for providing only one rotational alignment position between the male-male connector and the asymmetric abutment.

16. An attachment for securing a prosthetic crown to a dental implant, the attachment comprising:

- a male-male connector as defined in any one of claims 1 to 15; and

- an asymmetric abutment for receiving thereon said prosthetic crown, said abutment comprising a bottom portion comprising a female connecting portion adapted for receiving therein the second male connecting means of the connector, said female connecting portion being provided with second positioning means adapted for mating with said at least one anti-rotational element of the connector.

17. An attachment for securing a prosthetic crown to a dental implant, the attachment comprising:

- a connector comprising:

- second male connecting means extending in a second direction opposite to the first direction for engaging a corresponding female connecting portion located inside a bottom portion of said abutment, the second male connecting means comprising at least one anti-rotational element;

- an asymmetric abutment for receiving said prosthetic crown thereon, the abutment having a bottom portion comprising a female connecting portion adapted for receiving therein the second male connecting means of the connector;

wherein said at least one anti-rotational element and said second positioning means have complementary shapes configured for providing from one (1) to eight (8) rotational alignment positions between the male-male connector and the asymmetric abutment.

18. The attachment of claim 17, wherein said at least one anti-rotational element comprises first positioning means, and wherein the first positioning means and the second positioning means have substantially complementary shapes configured for providing only one rotational alignment position between the male-male connector and the asymmetric abutment.

19. A method for manufacturing an asymmetric abutment for installation in a patient's mouth, comprising:

- providing a three-dimensional computer model of a connector to be mounted on an implant positioned in the mouth of said patient, the connector comprising first positioning means; and

- creating a three-dimensional computer model of the asymmetric abutment to be manufactured, wherein said asymmetric abutment comprises second positioning means configured to fit with the first positioning means of the connector, the second positioning means being positioned for providing a single predetermined rotational alignment of the abutment to the connector.

20. The method of claim 19, wherein the first positioning means and the second positioning means have substantially complementary shapes.

21. The method of claim 19 or 20, comprising using said first positioning means as a point of reference for identifying said single predetermined rotational alignment of the abutment to the connector.

22. A method for manufacturing an asymmetric abutment to be mounted to a dental implant secured in a patient's mouth, comprising:

- providing a three-dimensional computer model showing an implant position in the patient's mouth; - providing a three-dimensional computer model of a connector adapted for mounting said asymmetric abutment to the implant, the connector comprising: first connecting means for engaging the dental implant; and second connecting means extending in an opposite direction from the first connecting means, the second connecting means comprising first positioning means adapted for mating with second positioning means inside a bottom portion of the asymmetric abutment to be mounted in the patient's mouth; creating a three-dimensional computer model of the asymmetric abutment to be manufactured, wherein said asymmetric abutment has a shape defined for a predetermined rotational position alignment relative to the rotational position of the dental implant, and determining the rotational position of the second positioning means relative an outer surface of the asymmetric abutment.

23. A kit comprising a male-male connector according to any one of claims 1 to 15 or an attachment according to claim 16, 17 or 18.

24. A prosthetic tooth comprising a male-male connector according to any one of claims 1 to 15 or an attachment according to claim 16, 17 or 18.

25. A method for installing a prosthetic tooth in the mouth of a patient, comprising securing to a dental implant located in the patient's jawbone a male-male connector according to any one of claims 1 to 15 or an attachment according to claim 16, 17 or 18.