RU2758756C1 - Method for manufacturing a metal-ceramic crown with a screw fixation on an implant - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, in particular to orthopedic dentistry, and is intended for use in orthopedic treatment with metal-ceramic crowns on dental implants. Using CAD/CAM software for the manufacture of prosthetic constructions, the framework of the future metal-ceramic crown on a screw-retained implant is modeled on a computer screen. In the upper third of the crown, a ledge is formed in its middle part, located between the lower and upper parts, of a cylindrical shape 3-4 mm deep and 1 mm wider than the existing shaft, closed with a soil ceramic mass flush with the shaft sealed with a composite material. Subsequent layers of ceramic veneers are then applied to the remaining parts of the crown in accordance with standard technology.

EFFECT: method allows, due to good adhesion to the ground ceramic layer of the composite material, ensuring reliable obturation of the shaft and the absence of dark metal transmission through the filling.

1 cl, 3 dwg, 1 ex

Description

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

A known method of manufacturing metal-ceramic crowns including the setting of the implant, fixation of the implant abutment and screw fixation of the prosthesis with a screw passing through the occlusal (chewing) surface of the prosthesis [Guide to dental implantology John A. Hockback; Roger M. Watson; Lloyd J. J. Sizn. Moscow "Medpress-inform" 2007, pp. 125-126]. In a similar way, metal-ceramic prostheses of various lengths are fixed from single artificial crowns to extended bridges on edentulous jaws. Screw fixation provides ease of removal of the prosthesis for examination and hygiene measures, the possibility of prosthetics with a minimum interalveolar distance.

There is a known method for restoring a dentition defect with a fixed denture (RU 2618308), in which the fixation of the structure is carried out by screwing the artificial crown directly to the implant, which ensures good strength of the connection.

There is a known method of making a pin (RU 2625280) to provide support for dentures, containing at least one upper hole into which a fixing screw is screwed to fix the prosthesis on the pin, including the following steps: taking an impression of the patient's oral cavity, modeling chewing load and aesthetic requirements patient, calculating the ideal position of the upper hole, developing the nail using data on the patient's oral cavity, individualizing the shape of the nail and the type of attachment to the prosthesis, transferring the file with the data obtained at the previous development stage to the planning stage for the manufacture of the nail and directly manufacturing the nail. The method is proposed to meet the specific mechanical requirements in each individual clinical case.

In all of these methods, the traditional final stage of crown placement is to close the screw shaft with a dental composite filling.

The main disadvantage of these, as well as other methods of manufacturing artificial metal-ceramic crowns on implants fixed with a screw, is the imperfection of the method for manufacturing a section of an artificial crown in its upper part, at the point where the screw enters the shaft. According to the traditional technology of manufacturing a metal-ceramic crown with a screw fixation on the implant, the inner surface of the screw shaft is made of metal, due to the fact that the hole is drilled in the monolithic metal frame of the future crown. When the filling is placed, the metal shines through its thickness, which leads to low aesthetic performance of such crowns. At the same time, it is difficult to ensure high-quality adhesion of the seal to the metal surface of the mine.

The objective of the present invention is to create a porcelain-fused-to-metal crown on an implant, which can completely eliminate these disadvantages.

The task is accomplished due to the fact that in our proposed method of manufacturing a metal-ceramic crown on screw fixation, in the upper third of the crown, in the process of manufacturing a metal frame, a cylindrical ledge is formed, 3-4 mm deep, and by 1 mm. wider than the existing shaft, expanding the shaft of the propeller at the point of its entry, and then covered with a soil ceramic mass flush with the shaft in the lower and upper parts.

A method of manufacturing a metal-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, "Dental Sistem Premium" - Denmark) for CAD / CAM manufacturing of orthopedic structures, the framework of the future metal-ceramic crown on a screw-retained implant is modeled on the computer screen. At this stage, in the upper third of the crown, in the place of the screw inlet, a cylindrical ledge with a depth of 3-4 mm is modeled, and 1 mm wider than the existing shaft, expanding the screw shaft at its entrance (Fig. 1). The obtained information in the form of a file is loaded into the milling unit, where the metal framework of the crown is made using the CAD / CAM method, in accordance with the data laid down. Further, in the process of applying a ceramic mass to a metal frame, the formed earlier ledge is closed with a soil mass flush with the existing walls of the screw shaft in its lower and upper third (Fig. 2). After that, the remaining parts of the crown are applied with the subsequent (dentin and enamel) layers of the ceramic veneer in accordance with the standard technology. The crown is then placed in the mouth using a screw and a torque screwdriver. The screw head is closed with sterile Teflon tape, and the screw shaft is sealed in layers (with dentin and enamel with preliminary bonding), with a composite material in accordance with the ceramic layers on the crown (Fig. 3). The advantage of the proposed method for manufacturing a metal-ceramic crown with a screw fixation on an implant is good adhesion to the ceramic base layer of the composite material, which ensures reliable obturation of the shaft and the absence of dark metal through the filling, which ensures high aesthetics of the occlusal surface of the crown.

Clinical example

Patient R., 51 years old, complained of absence 1.5. After clinical and X-ray examination, the patient was recommended to install a dental implant, followed by prosthetics with a metal-ceramic crown with screw fixation according to our method. After osseointegration of the implant in the area 1.5. 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 using the CAD / CAM method, a metal crown frame was made with a cylindrical shoulder in the upper third of the screw shaft 3 mm deep and wide. After fitting in the oral cavity, the ledge on the inner surface of the screw shaft is closed with a ground layer of ceramic in accordance with our proposed technique and further application of layers of dentin and enamel on the rest of the metal-ceramic crown (color A-3). After fitting, the crown is installed in the oral cavity, the screw is tightened with a torque screwdriver. The lower (metal) part of the shaft and the screw head are covered with sterile Teflon tape. After applying the bond, the screw shaft is layer-by-layer (dentin, enamel) obturated with a composite material "Filtec" -3-MEspe (Germany). Polymerized and polished. Dynamic observation for 3 years showed the absence of complaints from the patient and any complications. The integrity of the filling is preserved, the contact zone between the filling and the metal-ceramic crown is not broken.

Description of drawings

FIG. 1. Modeled and milled a cylindrical ledge (A) expanding the screw shaft.

FIG. 2. The metal frame and the ledge (A) are covered with a soil ceramic mass.

FIG. 3. Primer (A) is applied to the metal frame and the ledge in the screw shaft, on the surface of the frame is dentin (B), enamel (C) of ceramic mass. The screw shaft is closed with a composite filling material dentin (D), enamel (D).

Claims (1)

A method of manufacturing a metal-ceramic crown with a screw fixation on an implant consists in forming in the upper third of the crown, a ledge is formed in its middle part, located between the lower and upper parts, of a cylindrical shape with a depth of 3-4 mm and 1 mm wider than the existing shaft, closed with a ceramic ground mass flush with the shaft, sealed with composite material.

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