RU2817475C1 - Dental implant prosthetic component and abutment for its screw retention - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions relates to a prosthetic component of a dental implant and an abutment for its screw retention. Prosthetic component comprises an attachment base with a through hole for a prosthetic screw, made with a connecting socket in the form of an annular recess around the hole for the prosthetic screw, limited by a small diameter wall and a large diameter wall with support side surfaces of a conical shape, which are mutually coaxial and diverge outward. Abutment comprises a seat for the fastening base of said component with a threaded hole for the prosthetic screw. Seat is made in form of annular projection around hole for prosthetic screw, note here that said ledge has outer and inner bearing side surfaces of conical shape, which are mutually coaxial and converge outward.

EFFECT: higher tightness of screw connection of dental implant prosthetic component with its abutment, as well as increased rotational stability of prosthetic component relative to abutment with screw retention, which prevents loosening of the prosthetic screw and high reliability of the screw connection, which reduces the risk of inflammatory reactions and rejection of the implant.

8 cl, 5 dwg

Description

The invention relates to medical equipment, namely to components of a dental implant system. The technical solution is intended for use in the field of prosthetic dentistry for prosthetic treatment based on root-shaped endosteal implants.

Currently, endosteal implants consisting of a root-like body, an abutment, a prosthetic component and an artificial crown have found wide practical application in restorative dentistry. The body of the implant serves as a support for the entire structure. The abutment carries a prosthesis or implant superstructure connected to the abutment through a prosthetic component, in particular a prosthetic coping.

From patent document US 2006/0141419 A1 dated June 29, 2006, two types of dental implants are known: with cement or screw retention of the prosthesis. A screw-retained prosthetic implant consists in particular of a screw-retained abutment and a prosthetic component. This component includes in its design a flat mounting base with a through hole for a prosthetic screw. The abutment in turn contains a flat seat for the fastening base of the prosthetic component and a hole for the prosthetic screw, through which the prosthetic component is pressed to the abutment.

Implants with screw retention of the prosthesis have a number of advantages compared to implants based on cement retention. In particular, the prosthetic screw allows for a tighter mating of the joint surfaces by pressing them against each other and maintaining the pressing force for a long time. In addition, the threaded connection is removable, which simplifies the installation and maintenance of the implant. There is also no need to remove excess cement around the abutment from under the gum, which is extremely difficult in cramped oral conditions.

However, there is a danger that over time the screw retention in the known device will weaken due to external forces applied to the implant. Micromovements of the implant parts will cause the suction of oral fluid into the cavities of the implant through leaks in the connection of its parts, which do not provide the necessary protection of the threaded pair due to the impossibility of achieving such a high density of interface between the flat supporting surfaces to ensure the tightness of the unit with screw retention of the parts and its mechanical stability. Wetting the thread surface with oral fluid can reduce friction in the joint, which increases the likelihood of self-unscrewing of the prosthetic screw with a gradual increase in the amplitude of rocking of the parts until the screw fails.

In addition, the risk of prosthetic screw loosening is increased by the low rotational stability of the prosthetic component relative to the abutment due to the low amount of dry friction between the flat bearing surfaces. Moreover, in the known design there are no anti-rotation elements to prevent rotation of the prosthetic component relative to the abutment.

Insufficient reliability of the screw connection causes the risk of peri-implantitis and even loss of the implant due to bacterial contamination.

The present invention solves the technical problem of making the screw connection of the prosthetic component of a dental implant with its abutment more reliable and reducing the risk of inflammatory processes that can lead to rejection of the root-shaped endosteal implant.

The technical result provided by this invention is to increase the tightness of the screw connection of the prosthetic component of a dental implant with its abutment, as well as to increase the rotational stability of the prosthetic component relative to the abutment during screw retention.

The technical result is achieved thanks to the following design of a prosthetic component with screw retention for a dental implant. The fastening base of the prosthetic component contains a through hole for a prosthetic screw and a connecting socket in the form of an annular recess around the said hole. This recess is limited by a wall of small diameter and a wall of large diameter with supporting side surfaces of a conical shape, which are mutually coaxial and diverge outward.

In a particular case of the invention, the axis of rotation of the supporting side surfaces is coaxial with the longitudinal axis of the through hole for the prosthetic screw.

In another particular case, the annular recess is made from the condition of a smaller height of the supporting side surface of a small diameter relative to the supporting side surface of a large diameter with the same amount of taper of these surfaces.

In a particular case, the annular recess is made with an anti-rotation element.

Also, the technical result is achieved due to the fact that the seat of the abutment for screw retention of the prosthetic component of a dental implant, intended for the mounting base of the said component, is made in the form of an annular protrusion around the threaded hole for the prosthetic screw. Moreover, this protrusion has external and internal supporting side surfaces of a conical shape, which are mutually coaxial and converge outward.

In a particular case, the axis of rotation of the supporting side surfaces is coaxial with the longitudinal axis of the threaded hole for the prosthetic screw.

Also, in a particular case, the annular protrusion is made from the condition that the height of its internal supporting side surface is lower relative to the height of the external supporting side surface with the same amount of taper of these surfaces.

In another particular case, the annular protrusion is made with an anti-rotation element.

The essence of the invention is illustrated by the following drawings, which show the design of the main components of a dental implant as a preferred example of a technical solution.

Fig. 1: dental implant assembly.

Fig. 2: prosthetic component in the form of a cap.

Fig. 3: Abutment for screw retention of a prosthetic coping.

Fig. 4-5: geometric parameters of the connecting socket of the prosthetic cap and the seat on the abutment head.

The presented implant is intended to replace a jaw tooth. This implant consists of a number of parts, namely the endosteal root-shaped body of the implant 1, a single-part abutment 2, a prosthetic cap 3, an artificial single crown 4 and a prosthetic screw 5 (Fig. 1).

The prosthetic components are designed to fix a prosthesis, in particular a crown 4 or a superstructure, on an abutment 2. The cap 3 is a prosthetic component with screw retention and is characterized by an internal cavity and a predominantly circular cross-section. The cap body 3 contains a mounting base 6, in the center of which there is a smooth through hole 7 for the prosthetic screw 5 (Fig. 2). The diameter of the hole 7 is selected from the condition of free passage of the threaded part of the prosthetic screw 5. From the top of the cap 3, the channel of the hole 7 is widened for the head of the screw 5. On the opposite side, the hole 7 communicates with the cavity of the connecting socket intended for seating the cap 3 on the abutment 2.

The connecting socket of the cap 3 has the form of an annular recess around the hole 7, limited by a wall of small diameter 8 and a wall of large diameter 9, made with a skirt. These walls contain supporting side surfaces of a conical shape facing each other, located inside the cap 3. Moreover, these surfaces are mutually coaxial and are made diverging outward. In this case, the axes of rotation of the supporting side surfaces of the connecting socket coincide with the axis of the longitudinal hole 7 and with the central axis of the entire cap 3. The wall 9 of the annular recess is made with a pair of internal anti-rotation elements in the form of beads 10. On the outer surface of the cap 3, protrusions 11 are formed for cement fixation of the crown 4 or, if necessary, dental bridges and multi-support prostheses.

On the outer surface of the cap 3, there are preferably grooves 12 for holding the impression material when taking a dental impression, as well as edges 13, which make it possible to use the cap 3 as an analog or digital impression transfer when making a crown 4.

Abutment 2 serves as an artificial tooth stump and provides support for the prosthetic cap 3, as well as the formation of a gum ring 14. Abutment 2 has the shape of an oblong body of rotation, consists of a shank 15, a leg 16 and a head 17 (Fig. 3). The shank 15 is made with a threaded end part. The stem 16 is characterized by an axial narrowing, the magnitude of which is selected to ensure restoration of the gingival cuff around the implant. The head 17 consists of a gum former 18 and a seat for the cap 3. The leg 16 on one side is coupled with the shank 15 through the root conical part 19 of the abutment 2. On the opposite side, the leg 16 is smoothly coupled with the gum former 18 of the head 17. For the prosthetic screw 5 in the head 17 and leg 16 are formed with a corresponding blind threaded hole 20.

The seat on the head 17 of the abutment 2 is made in the form of an annular protrusion 21 with external and internal supporting side surfaces of a conical shape. These surfaces are mutually coaxial and converge outward, forming the apical conical part of the abutment 2. Moreover, the axes of rotation of the conical-shaped surfaces and the longitudinal axis of the hole 20 coincide with the central axis of the abutment 2. The annular protrusion 21 is made with two external anti-rotation elements, which are flats 22, the size of which corresponds to the size of the beads 10 on the wall 9 of the annular recess of the prosthetic cap 3. The seat on the head 17 in its geometric shape is a mate for the connecting socket of the prosthetic cap 3.

The annular recess of the cap 3 is made from a system of conditions (1).

Where:

H _c is the height of the supporting side surface of the large diameter wall 9 of the annular recess (Fig. 4);

h _c is the height of the supporting side surface of the small diameter wall 8 of the recess;

α _H - taper of the supporting side surface of the large diameter wall 9 of the recess;

α _h - taper of the supporting side surface of the small diameter wall 8 of the recess.

The parameters of the annular projection 21 of the abutment 2 satisfy the system of conditions (2).

Where:

H _c is the height of the outer supporting side surface of the annular protrusion 21 (Fig. 5);

h _c is the height of the inner supporting side surface of the protrusion 21;

β _H - taper of the outer supporting side surface of the protrusion 21;

β _h - taper of the inner supporting side surface of the protrusion 21.

To ensure tight coupling of the cones of the cap 3 and the abutment 2, the relations of the system (3) are valid in relation to the annular recess of the prosthetic cap 3 and the annular protrusion of the abutment 2.

The need to make a skirt on the wall 9 of the prosthetic cap 3 is due to the expansion of the diameter of the head 17 of the abutment 2 for the gum former 18.

The implant body 1 is a mechanical replacement for the root of a natural tooth. An external screw thread is cut on the body 1 to ensure stability in the bone 23, and a central shaft with a conical neck and an internal connecting thread for fixing the abutment 2 is formed inside.

The implant parts are preferably made from a titanium alloy suitable for surgical applications.

The assembly of this implant is carried out in the following sequence.

First, the endosteal body of the implant 1 is secured inside the jaw bone. Then the shank 15 of the abutment 2 is screwed into the central shaft of the body 1 to form a connection between the root conical part 19 of the abutment 2 and the conical neck of the said shaft.

Then a prosthetic cap 3 is temporarily put on the head 17 of the abutment 2. In this case, the connecting socket of the fastening base of the body 6 of the cap 3 is mounted on the seat of the head 17 of the abutment 2 with the support of the walls 8, 9 of the annular recess on the annular protrusion 21. Making the cap 3 and abutment 2, respectively with an annular recess and an annular protrusion, the conical lateral surfaces of which are supporting each other over the entire area of contact with screw retention of these parts due to the outward divergence of the conical surfaces of the cap 3 and the outward convergence of the conical surfaces of the abutment 2, subject to the condition of their alignment, ensures the formation of a double conical connection. The possibility of retaining the cap 3 and the abutment 2 with a prosthetic screw 5 is ensured thanks to the through hole 7 formed in the mounting base 6 of the cap 3 and a corresponding threaded hole in the body of the abutment 2. The prosthetic screw 5 is passed through the hole 7 in the body 6 and screwed all the way into the hole 20 , due to which the cap 3 is pressed against the abutment 2. Use the grooves 12 or the edges 13 of the cap 3 to make an analog or digital technological impression for the manufacture of a dental prosthesis. Next, the screw 5 is unscrewed and the cap 3 is separated from the abutment 2. The remaining impression material is removed from the grooves 12. Based on the resulting impression, a crown 4 of a suitable shape is made with a through hole 24 for screw 5.

Outside the oral cavity, the cap 3 is glued with cement to the base of the crown 4. Excess cement is completely removed from the area where the parts meet. The strength of the connection is ensured by protrusions 11, which increase the adhesion of cement to the outer surface of the cap 3.

Then the cap 3 is again put on the head 17 of the abutment 2, but with the crown 4, and the previously described screw retention process is repeated to press the cap 3 to the abutment 2. In this case, the cap 3 is the holder of the base of the crown 4. The prosthetic screw is tightened with the force required to achieve tight contact between the walls 8, 9 of the annular recess and the annular protrusion 21 along their entire diameter and mainly along their full height. If the crown 4 is made in advance, then the cap 3 is fixed to the head 17 of the abutment 2 immediately on a permanent basis.

As a final step, the inlet part of the hole 24 for the screw 5 in the crown 4 is sealed.

As a result, all of the listed implant parts are interconnected by assembly operations and are in functional and structural unity. The crown 4 is rigidly connected to the body of the implant 1 through the prosthetic cap 3 and the abutment 2.

Making a double protective conical connection of parts around the threaded pair ensures, in particular, an increase in the density of the interface between the prosthetic component of a dental implant and its abutment during screw retention, which has a positive effect on the tightness of the screw connection to the oral fluid, due to which the friction force in the thread does not decrease over time. Increasing the tightness of the interface between the prosthetic component and the abutment during their screw retention also leads to an increase in the rotational stability of the prosthetic component relative to the abutment due to the increased frictional force between the prosthetic component and the abutment.

To uniformly distribute the load in the area of contact of the prosthetic component of a dental implant with its abutment during screw retention and to achieve the highest density of interface between them, the prosthetic component and the abutment are preferably made from the condition of coaxiality of the rotation axes of the supporting lateral surfaces of the annular recess and protrusion relative to the longitudinal axis of the holes for the prosthetic screw.

Performing an annular recess of the prosthetic component and an annular protrusion of the abutment, respectively, from the condition Н _с >h _c and the condition Н _а >h _a , ensures, in the limited internal volume of the connection of these parts, part of which is occupied by the hole for the prosthetic screw, the possibility of meeting the system of conditions α _H =α _h , β _H =β _h , violation of which will lead to a decrease in the height of the internal cone or the size of its base, which will negatively affect the tightness of the screw connection and the rotational stability of the prosthetic component relative to the abutment.

When the annular recess and protrusion are equipped with anti-rotation elements, rotation of the prosthetic component relative to the abutment is completely eliminated, due to which the rotational stability of the prosthetic component is maximized.

Increased tightness of the screw connection and increased rotational stability of the prosthetic component prevent loosening of the prosthetic screw and give the screw connection high reliability, reducing the risk of inflammatory reactions and implant rejection.

Claims (8)

1. A prosthetic component with screw retention for a dental implant, containing a fastening base with a through hole for a prosthetic screw, characterized in that the fastening base is made with a connecting socket in the form of an annular recess around the hole for a prosthetic screw, limited by a small-diameter wall and a large-diameter wall with supporting side surfaces of a conical shape, which are mutually coaxial and diverge outward. 2. The component according to claim 1, characterized in that the axes of rotation of the supporting side surfaces are coaxial with the longitudinal axis of the through hole for the prosthetic screw. 3. The component according to claim 1, characterized in that the annular recess is made from the condition of a lower height of the supporting side surface of a small diameter relative to the supporting side surface of a large diameter with the same amount of taper of these surfaces. 4. The component according to claim 1, characterized in that the annular recess is made with an anti-rotation element. 5. An abutment for screw retention of a prosthetic component of a dental implant, containing a seat for the mounting base of said component with a threaded hole for a prosthetic screw, characterized in that the seat is made in the form of an annular protrusion around the hole for a prosthetic screw, and this protrusion has an external and internal supporting side surfaces of a conical shape, which are mutually coaxial and converge outward. 6. The abutment according to claim 5, characterized in that the axes of rotation of the supporting side surfaces are coaxial with the longitudinal axis of the threaded hole for the prosthetic screw. 7. The abutment according to claim 5, characterized in that the annular protrusion is made from the condition of a lower height of its internal supporting side surface relative to the height of the external supporting side surface with the same amount of taper of these surfaces. 8. The abutment according to claim 5, characterized in that the annular protrusion is made with an anti-rotation element.

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