RU2268021C1 - Method for carrying out prosthetics of minor included defects in dental rows in lateral department - Google Patents

Abstract

FIELD: medicine, orthopedic stomatology.

SUBSTANCE: the present innovation deals with adhesive fixation of retention elements with intermediate part upon supporting teeth. On defect-confining teeth one should prepare cavities for retention elements, temporarily close cavities to model intermediate part with supporting elements on an imprint-made gypsum model. The shape of intermediate part is a truncated cone at axial angle of 3°, bottom diameter and height being correspondent to an absent tooth, diameter of the upper area of a cone corresponds to 2.5 mm, and connective supporting elements should be designed as rectangular girders of 1.5 mm width, 2 mm height, at a right step in its lower part of 0.5 mm width and 0.2 mm thickness. The innovation provides minimally invasive dental preparing at simultaneous removal of carious tissues.

EFFECT: higher efficiency.

1 cl, 3 dwg, 1 ex

Description

The invention relates to medicine, namely to orthopedic dentistry.

Patients with small defects included, especially at a young age, rarely seek dental care. Although this pathology leads not only to a violation of the morphological unity of the dentition, but also to complex organic rearrangement in the area of the defect, which then extends to the entire dentition.

Most often, these processes are manifested in the movement of teeth, leading to a violation of the occlusal surface of the dentition, which subsequently complicates the clinic of partial tooth loss, sharply limiting the possibilities of orthopedic treatment. All this is especially relevant during the early loss of teeth, when the formation of the dentition is only completed.

Modern fixed prosthetics consists in the preparation of teeth, while traditional, based on crowns, implies the removal of 40 to 70% of hard tissues, which is often impossible without depulpation, and is sometimes complicated by the pathology that occurs at the contact point of the crown edge with the tissues surrounding the tooth. Based on this, it can be concluded that early replacement of dentition defects in the lateral department in young people is an urgent problem and requires further development of modern methods of orthopedic treatment in this group of patients.

As a prototype, the authors propose a “Crownless Bridge Works” (CBW) method of prosthetics with endless crowns, which meet the requirements of a sparing attitude to natural tooth tissues // Wolfram Olschowsky, Dr. med. dent. “Crownless Bridge Works”, M., “Quintessence”, No. 4, 1999. - P.27-40.

Dentures can also be used in the lateral parts of the upper and lower jaws. The CBW set consists of an angled micro-tip and accessories (5 microbores, 6 titanium and 4 zirconium lock tabs, a lock holder, 10 wax caps, a video cassette, instructions).

The method is as follows.

After an X-ray examination, hard tissues of the teeth limiting the defect are examined. The cavity for anchors is prepared with a special angled tip and burs. The supporting elements of the prosthesis are strengthened on the approximate surfaces of the supporting teeth using the acid etching technique. Laboratory-made prostheses are also adhesively fixed to CWB anchors.

A diagnostic impression of the alginate mass is removed, the angle of inclination of the teeth is estimated, if necessary, the walls of the supporting teeth are aligned with boron until parallelism is achieved. Using a special tip, microbores form cavities that are 1 mm from the gingival margin.

The tabs are installed in the holder and tried on, and then fixed to the polymer cement. A hydrocolloid or alginate impression is taken, along which the model is cast. An intermediate part with a retention pad located on the oral side is modeled on the model. Wax is transferred by laboratory to metal, the structure is strengthened in the oral cavity, then the color of the carcass lining is determined. They impose a ceramic mass, try on, glaze. After completion of all technological steps, the intermediate bridge element is fixed in the oral cavity on the retention elements of the anchor tabs by cement.

Certain disadvantages of the proposed method are:

- high-precision structural elements (standard tab locks, special tip, special microborons used no more than 2 times);

- the surfaces of the teeth facing the defect should be intact, which is very rare in the area of the jaw that has an included defect;

- relatively large sizes of the tooth cavity at a young age;

- high cost, since the details are standard and involve the use of original elements.

The authors propose a method for prosthetics of small included dentition defects in the lateral region.

Based on an objective examination of the teeth limiting the defect, X-ray examination, the state of hard tissues, the shape and size of the teeth limiting the defect are evaluated. Cavities are prepared that meet the following requirements: the width does not exceed ½ the distance between the transverse apexes of the tubercles, the optimal depth on the occlusal surface is 15-25 mm, the bottom is flat or having successive steps, the minimum convergence of the walls (total not more than 6 °).

Taking into account the adhesive nature of fixation with preliminary silanization of the prosthesis elements, there is no reason to complicate the shape of the cavity by significant grinding of hard tissues. The rationality of preparation, taking into account the clinical condition of the abutment, comes first (this primarily determines the type of abutment). Secondary preparation of enamel and dentin is performed (diamond heads of red, yellow, white). This contributes to maximum surface congruence and the optimum thickness of the cement to be fixed - 10-30 microns.

In certain areas, in the presence of a deep cavity and a short distance to the pulp, a treatment pad containing calcium hydroxide and insulating is used, which is highly durable and can withstand chewing pressure (glass ionomer, zinc phosphate cements).

Get a working and auxiliary prints. Vinyl polysiloxane impression material is used for the worker, alginate for the auxiliary. An occlusogram is performed using thermoplastic masses or non-aqueous elastomers in order to fix the central occlusion. The cavities on the teeth limiting the defect are closed with aqueous dentin or dentin paste for the period of manufacture of the microprosthesis.

Plaster models (simple) are made from prints. The models are gypsum-plated in the central occlusion position, in the place of the prepared cavities, compensation varnish is applied and the framework is modeled. The bridge frame is a structure of supporting elements and an intermediate part, which are sequentially made on the model by means of modeling wax. Supporting elements - tabs are modeled taking into account the anatomical shape of the teeth and occlusal relationships, to which from the side of the defect the intermediate part is modeled - the frame of the missing tooth (Fig. 1). Its shape is a truncated cone (1), the axial angle of which is 3 degrees. The diameter of the base of the cone and its height correspond to the conditionally prepared tooth. The diameter of the upper area of the cone is an average of 2.5 mm. It is equipped with two connecting supporting elements in the form of rectangular beams (2) with a width of 1.5 mm, a height of 2 mm, with a straight ledge in the lower part (3) of a width of 0.5 mm and a thickness of 0.2 mm, which allows the use of all-ceramic structures and simplifies subsequent hygiene measures.

A sprue system is glued to the occlusal surface of the intermediate part, whereby the modeling of the surface of the supporting elements and their maximum accuracy are preserved. Carry out the casting process. Alloys use cobalt-chrome, nickel-chromium, and also noble, which is favorable in the case of the further use of the all-ceramic crown. The metal frame of the microprosthesis of the tab is made (Fig. 2).

After removal of temporary fillings from the cavities of the teeth, the fabricated frame is tried on the prosthetic bed. The thickness of the film obtained by squeezing the tabs and adjacent to the mucosa of the alveolar process by the surface of the intermediate part, they are judged on their compliance. The optimum film thickness is 20-30 microns. The ratios of the framework with the teeth are estimated to be antagonists (it should correspond to the thickness of the proposed crown - 1.2-1.6 mm). After that, the outer surface of the tabs is polished, the inner surface of the tabs is processed in a sandblasting apparatus. The frame is fixed. After the hardening of the cement, the working double impression and the occlusogram are removed.

A combined model is made. Further at this stage, it is possible to manufacture various types of crowns: cermet, all-ceramic, plastic (permanent or temporary).

The advantages of this method of prosthetics:

- minimally invasive preparation of teeth limiting the defect;

- simultaneous removal of carious tissues in the area adjacent to the defect or on other surfaces of the tooth;

- the adhesive nature of the fixation allows you to not complicate the shape of the cavity;

- there is no need for significant grinding of hard tissues;

- when prosthetics with metal-ceramic, all-ceramic prostheses, depulpation of supporting teeth (at a young age) is mandatory. With the proposed method, depulpation is not shown;

- no special additional equipment is required;

- increasing the coverage of a significant number of young people (the need for which, according to various authors, is estimated from 15 to 40% at the age of 15-24 years), and at the very early stage, without waiting for the development of deformations of the dentition;

- the possibility of hygiene procedures;

- minimal impact on occlusal relationships;

- possible stages of treatment: replacing a plastic crown with a metal-ceramic or all-ceramic;

- high esthetics.

Clinical example.

Patient R. (medical history No. 18277), turned to the clinic with complaints of the absence of the right first molar of the upper jaw. The tooth was removed about 6 months ago due to complicated caries. Previously not prosthetized. He abandoned the traditional bridge because of the need for significant preparation of supporting teeth. Objectively: the bite is orthognathic, 15 - motionless, intact, 17 - motionless, on the medial-occlusal surface of the filling, presumably composite, not corresponding to the size of the cavity, caries relapse along the edge of the root and on the chewing surface. Clinical crowns of medium height, the axial slope of 15 and 17 is about 12 degrees. Moderate salivation, CPU = 4.

Diagnosed with partial tooth loss (small included defect in the dentition of the upper jaw on the right).

Treatment plan. Due to the patient’s reluctance to prepare abutment teeth under the crowns, a prosthetic bridge insert was planned. To do this, cavities were prepared in the abutment teeth for the fixing elements: in 15, a cavity 1.5 mm wide, 2 mm deep on the distal wall and 2.5 mm on the occlusal, 17 cavity was prepared taking into account the existing filling and carious process: on the medial surface 2.5 mm wide, on an occlusal complex configuration with a depth of 4 mm, which is why a treatment pad with calcium hydroxide was put on the projection of the pulp chamber, further insulating (glass ionomer cement). After processing the bottom (pulp wall), the depth of the cavity on the chewing surface was 3 mm. A working impression was taken from the upper jaw with vinyl polysiloxane material, an auxiliary alginate material from the lower one, the cavities at this stage were closed with aqueous dentin. Gypsum models are cast on which the wax framework of a bridge-like microprosthesis-insert is modeled. The wax composition is converted into metal by casting (figure 2). At the second visit, the frame is fixed in cavities previously cleaned from temporary material using polymer cement (adhesive technique). In subsequent visits, a ceramic-metal crown was made using traditional technology (Fig. 3).

The last follow-up examination after 2 years did not reveal any pathological changes in the supporting teeth and their periodontal. The prosthesis is fixed.

Claims (2)

1. A method for prosthetics of small included dentition defects in the lateral region, comprising adhesive fixation of the retention elements with an intermediate part on the abutment teeth, characterized in that the cavities under the retention elements are prepared on the teeth limiting the defect, the prepared cavities are temporarily closed on the impression made the gypsum model simulates the intermediate part with supporting elements, and the shape of the intermediate part is a truncated cone with an axial angle of 3 °, the diameter of the base and height, respectively existing missing tooth, the diameter of the upper platform of the cone is on average 2.5 mm, and the connecting supporting elements are made in the form of rectangular beams with a width of 1.5 mm, a height of 2 mm with a straight ledge in the lower part of a width of 0.5 mm and a thickness of 0.2 mm 2. The method according to claim 1, characterized in that the width of the cavity does not exceed 1/2 of the distance between the transverse tips of the tubercles, with an optimal depth on the occlusal surface of 15-25 mm, flat or with successive steps with a bottom and a minimum convergence of the walls of not more than 6 ° .

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