RU2758761C1 - Method for manufacturing an all-ceramic screw-retained crown on an implant - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, in particular to orthopedic dentistry, and can be used for orthopedic treatment with crowns on dental implants. The effect is accomplished due to the fact that in the proposed method for manufacturing a ceramic crown on a screw fixation, instead of a dental cement filling, a ceramic inlay made of zirconium dioxide is used, and at the initial stages of manufacturing (computer modeling) of a crown, parameters are set that ensure a high-quality adherence of the inlay to the ceramic surface of the crown.

EFFECT: creation of a ceramic crown (zirconium dioxide) on the implant, which allows avoiding filling the screw shaft with dental cements after installing the crown in the oral cavity and ensuring high-quality marginal adhesion of the filling to the ceramic surface of the crown covered with glaze.

1 cl, 2 dwg

Description

The invention relates to medicine, in particular to orthopedic dentistry, and can be used for orthopedic treatment with crowns on dental implants.

There is a known method of dental prosthetics, including the introduction into the jaw bone of an implant - a metal hollow body in the form of a cylinder or a truncated cone, having a screw thread on the outer and inner surfaces, installing a metal supragingival part (abutment) on the implant by fixing it with a screw inserted inside the implant, and cement fixation to the abutment of a prosthesis made of zirconium dioxide [Prosthetic outcome of cement-retained implant-supported fixed dental restorations: a systematic review. Chaar MS, Att W, Strub JR .; J Oral Rehabilitation. 2011 March, http://www.ncbi.nlm.nih.gov/pubmed/21395638]. Zirconium dioxide possesses high strength and high aesthetic qualities, which allows to obtain good results of orthopedic rehabilitation, especially in the anterior part of the jaws. However, the disadvantage of this method is the non-repairability of the structure, due to the impossibility of its easy removal due to cement fixation.

A known method of manufacturing ceramic crowns from zirconium dioxide (RU 2474401 dated 02/10/2013). The through hole is made in the form of a cut with anti-rotational grooves, in which a metal insert with anti-rotational protrusions and a screw shaft made of gold-platinum alloy is placed. The prosthesis is connected to the head with a screw passing through the specified insert. The technical result is the ability to manufacture prostheses from zirconium dioxide for screw fixation to the implant.

There is a known method of manufacturing a collapsible dental implant (RU 2593349) made of titanium, the apical part of which contains a hexagonal hole, at the base of which a blind threaded hole is made with a diameter of 0.5 to 1.1 mm, for an apical fixing screw with a length of 2.4 to 4.8 mm, cap diameter from 0.9 to 1.5 mm, providing connection between the apical and intermediate parts of the implant. The intermediate part contains a hexagonal hole, at the base of which there is a through hole with a diameter of 1.2 to 2 mm, containing a thread in the upper part, extending to the apical part. The artificial crown abutment is connected with a crown retaining screw.

The main disadvantage of these methods of making artificial crowns on implants fixed with a screw is the need to seal the screw shaft with dental cements after the crown is installed in the oral cavity. At the same time, it is impossible to ensure high-quality marginal adhesion of the filling to the ceramic surface of the crown covered with glaze. Another disadvantage is the low aesthetics of screw-retained crowns, due to the presence of a filling on their occlusal surface.

The object of the present invention is to create a ceramic crown (zirconium dioxide) on an implant, which allows to completely eliminate the indicated disadvantages.

The task is accomplished due to the fact that in our proposed method of manufacturing a ceramic crown on screw fixation, instead of a dental cement filling, a ceramic inlay made of zirconium dioxide is used, and at the initial stages of manufacturing (computer modeling) of a crown, parameters are set that ensure a high-quality adherence of the inlay to the ceramic surface of the crown. ...

The method of manufacturing a ceramic crown with a screw fixation on an implant is as follows. After the dental implant has engrafted and the healing abutment is installed, an impression of the dentition is taken with the help of impression transfers. In the dental laboratory, after the implant analogs have been installed, a plaster cast is cast into the impression. This model is scanned using a laboratory 3-D scanner (for example "3shape" - Denmark). Then, using software (for example, "DentalSistemPremium" - Denmark) for CAD / CAM manufacturing of prosthetic structures, an artificial crown on a screw-retained implant is simulated on the computer screen. At this stage, in the upper part of the crown, in the place of the screw inlet, a seat is modeled for a cylindrical inlay with a divergence of the walls of 2-3 degrees for a better fit of the inlay. The depth and width of the seat for full contact of two mating surfaces is 3-4 mm, depending on the depth of the screw shaft and the size of the occlusal surface of the tooth. After modeling the seat, its dimensional parameters are used for computer modeling of the zirconium dioxide insert, taking into account the required space for the cement film (Fig. 1). In the process of modeling the inlay, the anatomical parameters of the occlusal surface of the crown are taken into account in order to fully match them. The obtained information in the form of a file is loaded into a milling unit, where by the CAD / CAM method a crown and an inlay are made of zirconium dioxide in accordance with the laid down data (Fig. 2). They are tinted and glazed, and the inner surface of the insert seat is sandblasted. The crown is then placed in the mouth using a screw and a torque screwdriver. The final step is to install a tab to close the screw shaft using any adhesive system. The advantage of the proposed method for manufacturing a ceramic crown with a screw fixation on an implant is a tight fit of the inlay to the inner surface of the screw shaft due to their computer manufacture and the shape of the joint-to-joint seat, which ensures the durability of sealing and high aesthetics of the occlusal surface of the crown.

Clinical example

Patient K., 47 years old, complained of chipping of the ceramic veneer of the metal-ceramic crown with cement fixation on the implant in the area of 4.6. After clinical and X-ray examination, the patient was recommended to manufacture a ceramic crown with a screw fixation and to close the screw shaft with a ceramic insert. The previously made crown was removed, an impression transfer was installed, and two-layer impressions of the upper and lower jaw were taken. In the dental laboratory, with preliminary computer modeling by CAD / CAM method, a new zirconia crown with a seat for an inlay and a ceramic inlay (color A-2) was made. The inner surface of the screw shaft is sandblasted. After fitting, the crown is installed in the oral cavity, the screw is tightened with a torque screwdriver. The bottom of the shaft and the screw head are covered with sterile Teflon tape. Using the adhesive system "VariolinkII" (Germany), the screw shaft is closed with a ceramic insert. Polymerized and polished. Dynamic observation for 2 years showed the absence of complaints from the patient and any complications. The integrity of the ceramic inlay is preserved, the contact area of the inlay and the ceramic crown is not disturbed.

Description of drawings

FIG. 1 Crown and zirconium dioxide (A), with a modeled seat for the inlay and the inlay itself (B).

FIG. 2 Manufactured crown made of zirconium dioxide (A), with an installed insert (B) covering the screw shaft.

Claims (1)

A method of manufacturing an all-ceramic screw-retained crown on an implant, including computer modeling in the upper part of the crown, characterized in that a seat for a cylindrical inlay with a wall divergence of 2-3 degrees, a depth and width of 3-4 mm and the inlay itself, which are made by the CAD / CAM method from zirconium dioxide, while in the process of modeling the inlay, the anatomical parameters of the occlusal surface of the crown are taken into account in order to match them, and the inner surface of the inlay seat is sandblasted.

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