Message Dr_Arut » Mon May 16, 2016 5:23 am

To obtain a functional impression in dentistry, an individual spoon is used, which is made according to an anatomical cast. An individual tray matches the prosthetic bed as closely as possible and allows for functional tests, so the impression more accurately reflects it. There are four main ways to make custom spoons, listed below in chronological order.

Making an individual spoon from quick-hardening plastic;
Production of an individual spoon from a plate of thermoplastic plastic by vacuum forming;
Production of an individual spoon from a plate of a photopolymer composite;
3D printing.

The oldest and most common method is the manufacture of a spoon from cold polymerization plastic (Protacryl-M, etc.). To do this, a plaster model is cast from ordinary plaster (class II) according to the anatomical cast. Cut the model on the trimmer. Draw the border of the future individual spoon with a chemical pencil. Usually the border passes 1-2 mm before reaching the vestibule of the oral cavity, i.e. 1-2 mm shorter than the edge of the removable denture base. Also, the edge of the spoon does not reach the frenulum and strands by 1-2 mm. This space is necessary for the correct shaping of the margins with thermoplastic or viscous silicone impression materials.

Making an individual spoon from quick-hardening plastic.
After the borders are drawn, the undercuts are isolated with wax so that the finished individual tray can be removed from the model. Warm up the base wax plate and press it evenly onto the model. Cut it along the previously drawn border. In the region of the palate and alveolar processes in the lateral section, round or square holes (windows) are made in wax to create stops on an individual spoon, which in these areas will be in contact with the oral mucosa. This is done to create a uniform gap between the spoon and the mucosa, which will be filled with a corrective silicone mass. The window area is lubricated with insulating varnish (Isokol-69, Pikasep, petroleum jelly, vegetable oil, etc.).

Next, cold polymerization plastic is kneaded according to the manufacturer's instructions (usually in a 2: 1 weight ratio of powder and monomer). The easiest way to model a spoon made of cold-cured plastic is to use a special silicone mold with a base-shaped model a few millimeters high. A thin polyethylene film (food film, etc.) is laid on the bottom of the mold, the mixed plastic is poured into the mold, leveled in the mold and covered with a second layer of film on top. It is left for a few minutes for the maturation of the plastic and the transition to the “dough stage”. After that, the upper (second) layer of the film is removed, the plastic is pressed against the model with its upper side, respectively, it turns over and the lower layer of the film is on top. Further, the plastic adapts to the model through the film. The film is also removed from the excess, i.e. plastic that has gone beyond the boundaries of the spoon, a handle is modeled. If it is necessary to model the finger supports on the spoon in the lateral sections, then this is also done from the surplus.

Next, the dental technician waits for the resin to harden. After hardening removes the spoon from the plaster model, if necessary, separates the wax from the spoon. Shortens the spoon according to the drawn borders on the model. If necessary, perforations are made on the tray for better adhesion to the impression mass.

BUT. Film on the form;
B. Filling the mold with plastic and applying a second film on top;
AT. Spoon modeling;
G. View of the finished spoon.
Advantages:

Cheapness;
No grips in the area of undercuts;
No need for special equipment.

Flaws:

Toxicity, as the technician inhales the monomer vapours;
Limited simulation time;
The inconvenience of grinding the spoon (the material can melt and clog the cutter);
The need to isolate undercuts on the model;
The inconvenience of modeling the handle.

The invention relates to medicine, namely to prosthetic dentistry, and can be used in clinical practice for the manufacture of individual spoons for both jaws in prosthetics with complete removable lamellar dentures. For the upper jaw, a plastic plate is first made - a template, according to the shape of which the substrate is bent from a metal plate with a double-sided polyvinyl chloride coating, the sky is formed, for which the heated base wax plate is cut to the shape of the inner edge of the substrate side and the plate is poured to the edge of the substrate side with heated wax, fit the substrate on the alveolar process of the upper jaw, the outer edge of the side of the fitted substrate is pasted over with sprue wax, the back part of the substrate in the region of the tubercles of the upper jaw is cut with scissors and pasted over with sprue wax heated on the burner, the substrate is fitted on the alveolar process of the patient's upper jaw and the sides are processed using functional tests, then the substrate is transferred to an individual tray, for which a thin layer of the base silicone impression mass is covered with the inner surface of the substrate, the substrate is fitted on the alveolar process of the upper jaw and functional tests are carried out for processing of the silicone mass at the edge of the sides of the substrate, and after vulcanization of the impression mass, an individual tray for the upper jaw is obtained. For the lower jaw, a plastic plate is first made - a template, according to the shape of which the substrate is bent from a metal plate with a double-sided polyvinyl chloride coating, it is fitted onto the alveolar process of the patient's lower jaw, the edge of the side of the substrate is pasted over with sprue wax and again fitted onto the alveolar process of the lower jaw, while carrying out functional tests, then the substrate is transferred to an individual tray, for which a thin layer of the base silicone impression mass is covered with the inner surface of the substrate, it is fitted on the alveolar process of the lower jaw and functional tests are carried out to process the silicone mass at the edge of the substrate sides, and after vulcanization of the impression mass, an individual spoon for the lower jaw. EFFECT: possibility to make precise correction and fitting of the substrate directly in the patient's oral cavity, which leads to the exclusion of the steps of taking preliminary anatomical casts, casting models from plaster and manufacturing individual plastic spoons on them, thereby reducing the number of visits and reducing the labor intensity of the process of manufacturing individual spoons .

There is a known method of manufacturing an individual wax spoon directly in the oral cavity, followed by obtaining a working functional cast from it, developed at CITO by G.B. Brahman and Z.V. Kopp (V.Yu. 1968, p. 349.). However, the wax spoon in the mouth, under the influence of temperature, cannot withstand excessive pressure, the resulting impression is inaccurate.

There is a method recommended in the presence of sharp degrees of atrophy in the lower jaw, taking a preliminary impression with an individual wax spoon made in the oral cavity, with the manufacture of a rigid individual spoon according to the obtained model, with which functional casts are taken, then working models are cast, according to which wax is made. bases with occlusal rollers and determine the height of the lower face and the central ratio of the jaws (Doinikov A.I., B.V. Svirin. Obtaining a functional cast with an edentulous lower jaw and designing prostheses with sharp degrees of atrophy of its alveolar part. Guidelines, M ., 1981) The disadvantage of this method is its significant complexity.

There is a known method of using a special set of spoons for edentulous jaws (SR ivotrey, universal & spezial spoons (Ivoclar company) designed for simultaneous removal of approximate casts from both jaws with the mouth closed (“Impression materials in dentistry”, edited by T.I. Ibragimova, N.A. Tsalikova, pp. 40-42. During the taking of the cast, the height of the lower face is recorded. However, with this method, it is impossible to use the obtained casts for taking functional tests.

Known technology for the manufacture of individual impression trays using light-curing materials, such as Luxa Tray rosa transparent u blau (KOHLER) individo lux (Voco) ("Impression materials in dentistry" edited by T. I. Ibragimov, N. A. Tsalikova, p. 106). Since such spoons are made according to models in accordance with anatomical casts, they are expensive, very fragile and can injure the oral mucosa with sharp plastic edges.

According to the authors, the closest analogue (prototype) is a method for obtaining individual spoons from self-hardening plastics using wax compression matrices (Optimization of the technique for taking functional casts from edentulous jaws. B.P. Markov, E.S. Iroshnikova, V.Yu. Kabanov / Textbook. - MGMSU, 2004). For the manufacture of matrices on auxiliary plaster models, the boundaries of the spoons are marked, which, according to the authors, should not reach the deepest sections of the transitional fold by 2-3 mm (taking into account the stretching of the boundaries when obtaining preliminary casts), the mandibular tubercles should overlap strictly along the distal edge , and the maxillo-hyoid line is no more than 1 mm. The compression matrix for the upper jaw is made from two layers of base wax, for the lower jaw - from three. A layer of self-hardening plastic is applied to the inner surface of the matrix cooled in water, it is compressed under pressure, the boundaries of the spoon are specified using functional tests. The disadvantages of the prototype include the complexity and complexity of the technology. Since the spoon is prepared according to an auxiliary plaster model cast in an anatomical cast taken from the edentulous jaw with a standard spoon, this leads to mucosal braces and inaccuracies in the transfer of anatomical features.

The main problem to be solved by the present invention is the development of a method for manufacturing an individual tray using a plastic atraumatic material that has good adhesion to both wax and impression mass, and the possibility of direct fine correction and fitting in the patient's mouth. This will improve the quality of treatment, simplify the technology for manufacturing an individual spoon and reduce the number of visits to the doctor by the patient.

The proposed method for manufacturing an individual spoon on the example of the upper jaw is as follows. A plastic plate is made - a template for the upper jaw. According to the shape of the template, a substrate is bent from a metal plate with a double-sided polyvinyl chloride coating (PE-X / Al / PE-X), which has good adhesion both with wax and with the impression mass. Dovetail-shaped incisions are made at the ends of the substrate in the region of the tubercles of the alveolar processes of the upper jaw. To form the palate, a plate of heated base wax is cut to the shape of the inner edge of the substrate edge and the plate is poured to the edge of the substrate edge with heated wax. The substrate is fitted on the alveolar process of the upper jaw, the outer edge of the fitted substrate is pasted over with sprue wax with a diameter of 2.5-3.0 mm, the back section of the substrate in the region of the tubercles of the upper jaw is cut with scissors and pasted over with sprue wax heated on a burner. The substrate is fitted on the alveolar process of the upper jaw of the patient and the sides are processed using functional tests. To transfer the substrate into an individual tray, the inner surface of the substrate is covered with a thin layer of the base silicone impression mass. The substrate material provides good adhesion to the silicone impression material. The substrate is fitted on the alveolar process of the upper jaw and functional tests are carried out to process the silicone mass at the edge of the sides of the substrate. After vulcanization of the impression mass, an individual tray for the upper jaw is obtained.

In the manufacture of an individual spoon for the lower jaw, a plastic plate is also first made - a template for the lower jaw, according to the shape of which the substrate is bent from a metal plate with a polyvinyl chloride coating, and it is refined. The substrate is fitted on the alveolar process of the patient's lower jaw so that the edge of the side of the substrate does not reach the transitional fold of the oral mucosa by 1.5-2.0 mm, bypassing the natural frenulums and bands. The edge of the side of the substrate is pasted over with sprue wax and again fitted onto the alveolar process of the lower jaw, while functional tests are carried out, in which the sides of the substrate are processed by the mimic and chewing muscles of the lips and cheeks. Then the substrate is transferred into an individual tray, for which a thin layer of the base silicone impression mass is coated on the inner surface of the substrate. Next, the substrate is attached to the alveolar process of the lower jaw and functional tests are carried out to process the silicone mass at the edge of the sides of the substrate, and after vulcanization of the impression mass, an individual tray for the lower jaw is obtained.

The proposed method for manufacturing an individual spoon has the following advantages:

1. The substrate material is plastic and atraumatic in relation to the oral mucosa.

2. The metallized layer of the substrate allows precise correction and fitting of the substrate directly in the patient's mouth, which leads to the exclusion of the steps of taking preliminary anatomical casts, casting models from plaster and manufacturing individual plastic spoons from them.

3. The substrate material has good adhesion with wax and impression mass, which eliminates the need for bonding systems. This allows one-stage production of occlusal wax rollers on an individual spoon, with the help of which the height of the lower face is determined and the central ratio of the jaws is fixed. Therefore, one more stage is excluded (i.e. a visit by the patient to the dentist) - determining the height of the lower face and fixing the central ratio of the jaws using wax bases with occlusal wax rollers.

4. After special treatment of wax occlusal rollers located on the ridges of the received individual spoons, according to the Christensen phenomenon, it is possible, by adding a thin corrective layer of silicone impression mass (spidex cream), to obtain accurate functional casts simultaneously from the upper and lower jaws during the period of natural physiological movements of the patient's lower jaw, which could not be done before when taking functional casts with other types of individual spoons.

The proposed features, namely, the manufacture of a plastic plate - a template for the upper jaw, according to the shape of which the substrate is curved from a metal plate with a polyvinyl chloride coating, the formation of the palate, for which the plate of heated base wax is cut to the shape of the inner edge of the substrate side and the plate is poured to the edge of the side of the substrate heated wax, fitting the substrate on the alveolar process of the upper jaw, gluing the outer edge of the edge of the fitted substrate with sprue wax, trimming the back section of the substrate in the area of the tubercles of the upper jaw and gluing it with sprue wax, fitting the substrate on the alveolar process of the patient's upper jaw, processing the sides of the substrate using functional tests , transferring the substrate into an individual tray, for which a thin layer of the base silicone impression mass is covered with the inner surface of the substrate, the substrate is fitted on the alveolar process of the upper jaw and functional tests are carried out to process the silicone mass at the edge of the sides of the substrate, obtaining an individual tray for the upper jaw after vulcanization of the impression mass, as well as the following features - the manufacture of a plastic plate - a template for the lower jaw, according to the shape of which the substrate is bent from a metal plate with a polyvinyl chloride coating, fitting it onto the alveolar process of the lower jaw of the patient, gluing the edge of the side of the substrate with sprue wax, fitting the substrate onto the alveolar process of the lower jaw with functional tests, transferring the substrate to an individual tray, for which a thin layer of the base silicone impression mass is coated on the inner surface of the substrate, fitted onto the alveolar process of the lower jaw and functional samples for processing the silicone mass at the edge of the sides of the substrate, obtaining after vulcanization of the impression mass of an individual spoon for the lower jaw, were not found in known solutions, which allows us to conclude that the proposed solution meets the criterion m "novelty" and "technical level".

When manufacturing an individual spoon for the lower jaw, a chute was made from a metal plate 2.7 mm thick with a PVC double-sided coating in accordance with the plastic template for the lower jaw. The lingual side of the substrate segment is leveled with the help of crampons and, as a result, it becomes flat from a semicircular one. Examining the alveolar processes of the oral cavity, the doctor determines their width, height, notes the severity of the frenulum, and right next to the chair forms a substrate from the above-described metal-polymer blank. Places for bridles and strands are sawn out using a tip with a carborundum disk. The cut edge of the substrate is smoothed with a carborundum head. The substrate is treated with alcohol and fitted in the oral cavity on the lower jaw. In this case, the substrate is easily bent according to the shape of the patient's alveolar process using crampon forceps. The sides of the substrate do not reach the transitional fold and the bottom of the oral cavity by 2-3 mm, if conditions permit - the height of the alveolar process.

The edge of the board of the substrate is processed with a carborundum stone or a head, and a wax flagellum 2-3 mm thick is glued to it along the entire length. The wax is heated over a gas burner or spirit lamp and the backing is inserted into the patient's mouth. In this case, the patient is asked to perform functional movements of the cheeks and tongue according to the method of MGMSU. In places where there is a highly compliant alveolar mucosa and dangling mucosa, the substrate is perforated in these projections using a No. 3 carbide cylindrical bur.

The basic soft silicone impression mass (optasil, speedex) is laid in the fitted individual substrate. The mass is placed in a thin, even layer on the inner surface of the substrate, is introduced into the patient's oral cavity and is located on the alveolar process along the specified boundaries, after which the functional movements of the lips and cheeks are again carried out. After vulcanization of the impression mass, the resulting finished spoon is removed from the oral cavity, while the center of the alveolar ridge is marked on the spoon, and a wax occlusal roller of standard sizes is added to the spoon along this mark.

An individual spoon for the upper jaw is made somewhat differently. The initial stage of manufacturing a substrate for the upper jaw from a metal polymer is the same as for the lower one. The difference is that at the ends of the substrate, cuts 8-10 mm long are made with dental scissors and the edges are bent inward, recreating the shape of the tubercles of the upper jaw, and the missing part of the palate on the substrate is formed from a wax plate 3-5 mm thick. The edge of the side of the substrate is also treated with a carborundum stone, pasted over with a wax flagellum 3 mm thick, the heated substrate is introduced into the patient's mouth and located on the upper jaw. The patient is asked to carry out a series of functional movements developed according to the MGMSU method for the upper jaw.

As well as on an individual substrate fitted to the lower jaw, on a fitted substrate of the upper jaw in places of pliable and dangling mucous membrane, as well as in the area 15 14|24 25 teeth are perforated with a solid cylindrical bur No. 3. A thin layer of silicone base impression mass (optasil, speedex) is applied to the substrate and it is introduced into the patient's oral cavity and is located on the upper jaw. In this case, the patient is asked to repeat the functional movements until the complete vulcanization of the impression mass. The center of the alveolar ridge is marked on the substrate, a hole is made in the impression mass in the area 15 14|24 25 teeth and an occlusal wax roller of standard sizes is added to the received spoon.

In this way, individual metal-polymer trays with functional casts are prepared. Wax occlusal ridges were prepared on the spoons for further functional and phonetic tests and the final design of functional casts.

Individual spoons with functional casts and occlusal wax rollers are inserted into the oral cavity and placed on the alveolar processes. A prosthetic plane is created on the upper occlusal ridge using the Sorokin arc. According to the Christensen phenomenon, the articulation surfaces of wax occlusal ridges are processed. Grooves are made on the upper occlusal roller in the area 16 15|25 26 teeth.

The further technique is as follows: spoons with occlusal rollers are removed from the oral cavity and a thin layer of duplicating silicone impression mass is placed in the spoons, the spoons are reintroduced into the patient's oral cavity and he is asked to conduct a series of functional and phonetic tests, which allows the final formation of functional casts in the cavity mouth.

Occlusal roller on the lower individual tray in the area with 16| on |26 trimmed in height by 1.5-2 mm. A softened wax roller 2-3 mm thick is applied to this place and the patient's jaws are closed in a central relationship. Spoons are removed from the oral cavity, cooled and the occlusal rollers are separated with a spatula. Then the spoons are reintroduced into the oral cavity and the central ratio of the jaws is again controlled. Appropriate markings are made on the upper and lower occlusal rollers. Spoons are removed from the mouth. Based on functional casts taken from the upper and lower jaws, models of the jaws are cast from supergypsum.

Patient K., 72 years old, complained of poor chewing of food, gastrointestinal disorders, and impaired diction. Two and a half months ago, she was fitted with complete removable lamellar dentures in the polyclinic in Ivanovo. The patient has been using similar prostheses for 20 years. Can't get used to the latest dentures. Multiple corrections of prostheses do not bring relief. Can only chew soft foods, harder foods cause soreness. Recently, there have been pains in the epigastric region, a feeling of heaviness, belching after eating. When talking, the patient has swallowing of saliva, hissing sounds slip through.

When examining the oral cavity, an average uniform atrophy of the alveolar process of the upper jaw is observed (II degree of atrophy according to Doinikov A.I.) On the lower jaw, the alveolar ridge is expressed in the frontal area (IV degree of atrophy according to Doinikov A.I.) The mucous membrane of the oral cavity and alveolar processes edematous and hyperemic, especially in the region of the tubercles of the upper jaw and in the retromolar regions of the alveolar process of the lower jaw. When examining the oral cavity with fitted prostheses, an external examination shows a slight decrease in the lower third of the face. On the occlusal surfaces of the dentition, when checking the density of contacts using Bausch maps in the area single contacts were noted, there was no density of contact of fissure-tubercle contacts. During palpation examination, balancing of the prosthesis on the alveolar process of the lower jaw was observed, a slight balancing was observed in the prosthesis fitted on the upper jaw.

The patient was asked to make new prostheses according to the alternative method described above, having previously treated the oral mucosa. After following the recommendations, the patient came to the reception and on the first visit, templates of 0.8 mm thick polyvinyl chloride plastic were made according to the shape of the alveolar processes of the upper and lower jaws. On them, from a metal plate with a double-sided polyvinyl chloride coating (PVC material), substrates for the upper and lower jaws were made. In the patient's oral cavity, they were fitted onto the alveolar processes and, using the silicone impression mass, the spidex cream were transferred into individual spoons. Then, occlusal wax rollers were cast to the spoons, with the help of which the height of the lower third of the face was determined (having previously determined the prosthetic plane). The occlusal surface of the ridges was processed according to the Christensen phenomenon, and with the help of silicone impression mass cream "spidex" functional casts were taken at the same time at the time of physiological movements of the lower jaw with the jaws closed.

Then the central ratio of the jaws was registered in the patient and the work was transferred to the dental laboratory. On the basis of supergypsum casts, models were made, which were installed in the average position of the interframe space of the articulator of the hinge-ellipse type, and fitted to the frames of the articulator. With the help of a special device, artificial teeth were placed on the wax basis of the upper jaw model. The setting of the teeth on the wax basis of the lower jaw model was made on the occlusal surface of the dentition located on the wax basis of the lower jaw model.

On the second visit, the patient was tested for the design of the prostheses: the height of the lower face, the density of the closure of the dentition, the color and shape of the artificial teeth were checked, and then the wax bases with the artificial teeth were transferred to the laboratory to replace the wax with plastic.

On the third visit, the patient was fitted with complete removable lamellar dentures for the upper and lower jaws. A check was made of the density of contact of the occlusal surfaces of the dentition using Bausch maps. A check was made of the sliding of the occlusal surfaces of the dentition during sagittal and transversal movements of the lower jaw. Two supercontacts were identified, which were removed using a spherical burr.

A week later, the dentures were re-corrected. There was a small namin in the retromolar region of the alveolar process of the lower jaw on the lingual side on the right, the correction was performed with a carborundum head. Thereafter, no adjustments were made to the prostheses. Diction improved, with good chewing of food, pain in the epigastrium disappeared.

A method for manufacturing individual spoons for the upper and lower jaws, characterized in that for the upper jaw a plastic plate is first made - a template, according to the shape of which the substrate is curved from a metal plate with a double-sided polyvinyl chloride coating, the sky is formed, for which the heated base wax plate is cut to the shape of the inner the edges of the substrate side and pour the plate to the edge of the substrate side with heated wax, fit the substrate onto the alveolar process of the upper jaw, paste over the outer edge of the side of the fitted substrate with sprue wax, cut the back of the substrate in the area of the tubercles of the upper jaw with scissors and paste over with sprue wax heated on the burner, fit the substrate on the alveolar process of the upper jaw of the patient and the sides are processed using functional tests, then the substrate is transferred to an individual tray, for which a thin layer of the base silicone impression mass is covered with the inner surface of the substrate, the substrate is laid on the alveolar process of the upper jaw and functional tests are carried out for processing the silicone mass at the edge of the sides of the substrate, and after curing the impression mass, an individual spoon for the upper jaw is obtained; for the lower jaw, a plastic plate is first made - a template, according to the shape of which the substrate is bent from a metal plate with a double-sided polyvinyl chloride coating, it is fitted onto the alveolar process of the patient's lower jaw, the edge of the substrate board is pasted over with sprue wax and again fitted onto the alveolar process of the lower jaw, while carrying out functional tests, then the substrate is transferred to an individual tray, for which a thin layer of the base silicone impression mass is covered with the inner surface of the substrate, it is fitted on the alveolar process of the lower jaw and functional tests are carried out to process the silicone mass at the edge of the substrate sides, and after vulcanization of the impression mass, an individual spoon for the lower jaw.

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The invention relates to medicine, namely to orthopedic dentistry, and can be used in clinical practice for the manufacture of individual spoons for both jaws in prosthetics with complete removable lamellar dentures

Stages of making an individual spoon. individual spoons

Report on the topic: Methods for the manufacture of individual spoons. functional tests. Functional casts, classification. Rationale for the choice of impression material. Characteristics of various impression materials. Completed by a 4th year student gr. st - 402 a Aryslanova E. Kh.

No. Elements of Self-Control Stages of work Technique 1. Plaster model, cast on an anatomical impression Along the transitional fold, bypassing the frenulums of the cheeks, lips, tongue, capturing the tubercles Draw a chemical c. hours and retromolar pencil tubercles of the lower jaw border of the spoon. and passing in the sky by 2 mm. distally beyond the "A" line 2. Heat the plate over Visually monitor the flame to Standard fit. plate AKP-P, uniform If it is absent spirit lamp, softening, re-heat and spatula. compress it to compress the plate. models. 3. Chemical pencil. Transfer the boundary to the surface Monitor the accuracy of the crimped plate.

4. 5. 6. Scissors, drill, fissure bur, cutter. Achieve exact Adjust the border of the coincidence of the border of the spoon according to the marking of the spoon with the markings using a drill. on the model. Wire, crampon forceps Bend a handle from an orthodontic wire or a paper clip. To do this, bend the paperclip in half and bend the ends along the alveolar process. The height of the handle should be 1 - 1.5 cm. The ends should diverge in the direction of the alveolar ridge. Spirit lamp, crampon tongs. Attach the handle to the spoon. To do this, heat the bent ends, holding it with crampon tongs and immerse it in the plate. The handle should be fixed at an angle of 45 degrees to the plane of the spoon and protrude in the mesial direction.

Indications Accurate impressions for crowns, bridges, partial dentures and complete dentures Benefits Easy design and adaptation Long working time Odorless Reuse of excess material Curing in a standard lab curing machine with UV or halogen light (wavelength 240-520 nm) Optimum thickness Supertec

n The technique for manufacturing individual spoons and base spoons from self-hardening plastic Carboplast is as follows. The prepared plaster model is treated with isocol insulating varnish. Then the plastic carboplast is kneaded and the spoon is molded on the model. The mass hardens in air for 3-5 minutes. The processing and polishing of the spoon is ordinary.

1. Plaster model obtained from the anatomical impression Draw the border of the spoon with an indelible pencil. Along the transitional fold, bypassing the frenulums of the cheeks, lips, tongue, capturing the tubercles in. hours and retromolar tubercles of the lower jaw and passing in the sky by 2 mm. distally behind the line "A" 2. Base wax, spatula, spirit lamp. To model, according to the marked boundaries of softened wax on the model, an individual spoon and a handle to it. Check the conformity of the borders and the exact fit of the wax reproduction to the surface of the model. Cuvette, byugel, "Isokol". Prepare the model for plastering in a cuvette in the reverse way and plaster. Evaporate the wax, treat the cuvette with Isocol. After opening the cuvette, check the integrity of the model, the accuracy of matching the cuvette, the quality of the application of "Isocola". 4. Basic plastic. Prepare plastic dough, lay it on the model, place it under a press, polymerize the plastic. The correct ratio of powder and liquid, observe the polymerization mode. 5. Tools and finished customized spoon materials for grinding. grinding. 3. The spoon should not be rough, should fit the boundaries.

For the upper jaw. 1. Base wax, alcohol lamp Fold the wax plate across three times, heat it up and round off one edge, then squeeze the tubercle of the upper jaw, the alveolar process in the mouth, press it against the sky, remove, cool, cut off the excess, then soften again and repeat the crimp, controlling border with the movement of the cheeks, lips, and then form the back edge behind the line "A". Wax individual spoon should fit snugly to all surfaces of the prosthetic field, do not go to the movable mucous membrane, bypassing all the folds and frenulum of the tongue.

For the lower jaw. 2. Base wax, spirit lamp. Fold the wax plate (2/3 of it) in three lengthwise, compress according to the model, be sure to capture the retromolar space. At the end of the formation, a wire is laid along the spoon and strengthened with an additional wax roller. The spoon should lie motionless on the alveolar process, capturing the retromolar tubercle.

At present, it is common to manufacture a base individual spoon from self-hardening plastics 1. Plaster model, self-hardening plastic, chemical pencil, base wax, drill, abrasives for plastic. Draw the borders of the spoon on the plaster model with a pencil. Warm up the wax plate, press the model tightly and cut off the excess wax according to the borders. Heat up again and crimp a new wax plate over this one, slightly overlapping its edge. Then remove the wax plates, lubricate the model with Isokol, knead the plastic, lay it in an even layer on the model and press it with the second, upper wax plate, remove excess plastic behind the edges of the wax plate. After the plastic has hardened, process the edges and make a handle (they can be strengthened on the wax plate. Uniform heating of the plates, tight crimping of the model, exact matching of the boundaries, elasticity of the plastic dough, complete hardening, good machining.

When fitting a spoon on the upper jaw, it should be taken into account that the border of the prosthesis from the vestibular side should cover the pliable mucous membrane, squeezing it somewhat and being located 1-2 mm below the transitional fold, contact with its dome (movable mucous membrane) and have a concave vestibular surface. With this configuration, the edges of the prosthesis will fit snugly, and the fixation will be better, as this prevents air from entering under the prosthesis. The position of the impression along the line “A” is important for fixing the prosthesis. In this place, it should end on the soft palate, moving to it by 1-2 mm. The soft palate should be photographed in an elevated position. If this condition is not met, the impression will be taken with the palate lowered. The prosthesis in this case will be poorly fixed during eating and talking, as the soft palate rises, passing air under the prosthesis. In order to squeeze out the soft palate when taking an impression, a strip of thermoplastic mass is applied to the palatine edge of the spoon, wax 4-5 mm wide and 2-3 mm thick can be used. However, it should not be superimposed on the edge of the spoon in the place where it can push back the pterygomandibular fold, that is, the alveolar tubercles should be free. Then the spoon is inserted into the mouth and pressed against the sky with the mouth half closed. When the mass hardens, the spoon is removed from the mouth.

Fitting an individual spoon to the lower jaw also begins with the release of the frenulum of the lip and tongue, as well as the lateral strands by creating recesses in the edge of the prosthesis. This can be done with a narrow fissure bur, discs, wheel head. The mucous tubercles (tuberculum mucosum) serve as a guideline for determining the distal border. They are partially or completely covered with a spoon, depending on their shape, localization, consistency, the presence or absence of pain on palpation. There is no consensus on this issue and it is decided individually. On the lingual side in the lateral sections, the spoon should overlap the internal oblique line if it is rounded and reach it with an acute form, but its posterior lingual edge must necessarily be in a muscleless triangle. In the presence of exostoses in the anterior part of the alveolar process, the spoon covers them, leaving the excretory ducts of the sublingual glands free.

1. Ask the patient to swallow saliva. If at the same time the spoon is dropped, it is necessary to shorten its edge from the place behind the tubercle to the jaw-hyoid line. 2. Then ask the patient to slowly open his mouth. If at the same time the spoon rises from behind, then it is shortened in the area from the tubercles to the place where the second molar will later stand (2). You can grind the spoon very close to the bumps, but they should never be left free. If the front part of the spoon rises, then its edge from the vestibular side is ground off in the area between the fangs (3). 3. Draw your tongue along the red border of the lower lip. If the spoon rises, then grind off its edge, which runs along the maxillo-hyoid line (4). 4. Touch the tip of the tongue to the cheek with a half-closed mouth. The place of the necessary correction is located at a distance of 1 cm from the midline on the hyoid edge of the spoon (5). When the tongue moves to the left, correction may be required on the right, when the tongue moves to the right, on the left side.

5. Run your tongue along the red border of the upper lip. Correction of the edge of the spoon is done at the frenulum of the tongue concave, but not in the form of a groove (6). 6. Active movements of the mimic muscles, stretching the lips forward. If the spoon rises, then once again shorten its outer edge between the fangs (3). Between the canine and the second premolar along the vestibular edge of the spoon there is a place where the edge that goes too deep is pushed out passively by the tissue. If you put your index fingers slightly below the corners of your mouth and make massaging movements without pressure, then in this place (7) you can clearly feel the edge of the spoon going too deep. All movements except the last must be performed by the patients themselves.

1. Wide open mouth. If at the same time the spoon is displaced, then the edge is subject to shortening. 2. Cheek sucking. If the spoon is displaced at the same time, then its edge should be shortened in the region of the buccal frenulum (3). 3. Lip stretching. If the spoon is displaced in this case, its edge should be shortened in the anterior section (4).

Functional tray – functional impression The purpose of taking a functional impression is: to determine the maximum support area of the prosthesis base, taking into account muscle movements.

The functional cast must convey: On the upper jaw: transitional fold of the jaw crest with tubercles of the upper jaw (Tuber maxillaris) and the palate transition from hard to soft palate (A-line) of the frenulum and cord On the lower jaw: crest of the jaw with retromolar triangle (Trigonum retromolare) transitional fold and sublingual areas of the beginning of the muscles and ligaments of the lingual and buccal muscles of the frenulum and cord

Functional casts, classification n n n - According to the method of shaping the edges: With the help of passive movements Chewing and other types of movements With the help of functional tests Their combinations By the degree of pressure on the mucous membrane: Under pressure (compression) With minimal pressure (decompression or unloading) differentiated By the pressure method on the mucous membrane of the prosthetic bed: Arbitrary Dosed Chewing Combined

Compression impression according to E. I. Gavrilov. When applying a compression impression, the buffer zones of the hard palate partially dampen the masticatory pressure and thereby provide some unloading of the alveolar processes, reducing their atrophy. Compression impressions are taken under certain conditions: 1 - only a rigid spoon is used, 2 - only thermoplastic materials or materials of the same density are used to take the impression, 3 - continuous pressure is applied during removal, which stops only after the material has completely cured. Continuity of pressure is ensured by the effort of the doctor's hands, or the use of special devices, under bite pressure. Compression impressions are indicated for slight atrophy of the alveolar processes and dense mucous membrane.

Decompression impressions. Impression material without distortion reflects all the details of the prosthetic bed. In this case, liquid impression materials are used. The fixation of prostheses made from decompression impressions is relatively weak. Decompression impressions are indicated for complete atrophy of the alveolar processes and increased sensitivity of the mucous membrane.

differentiated impressions. Provide a selective load on certain parts of the prosthetic bed, depending on their functional endurance. To do this, either isolation is carried out on the model of those areas that must be unloaded, or perforations are created in an individual spoon in places where the mucous membrane is unloaded. It is necessary to shape the edges of the impression tray with thermal mass or wax before taking the impression. The impression is taken under arbitrary or chewing pressure. Differentiated impressions are shown with uneven atrophy of the alveolar process, the presence of a pronounced palatine torus.

Type of impression TYPE OF MATERIAL Compression plaster, dentol, repin, alginate masses (GC Aroma Fine (GC), Dust Free III (DMG)), polyester masses (Pentamix (3 M ESPE)) Decompression Silicone impression materials: Alphasil C-silicones (Omicron ), Speedex (coltene), Zetaflow (Zhermack), Xonigum-Putty, Dentstar (DMG), A-silicones GC Exajet, Betasil (GC), Bisico, thermomass, dentofol, thiodent, sielast Combined Combinations of the above types of materials

Gypsum. Soft, used for making impressions Gypsum has long been the main material for impressions. This is due to its availability and low cost. In addition, it gives a clear imprint of the surface of the tissues of the prosthetic bed, is harmless, does not have an unpleasant taste and smell, practically does not shrink, does not dissolve in saliva, does not swell when wetted with water, and is easily separated from the model when using the simplest separating agents. When taking an impression with gypsum on the upper jaw, a spoon with gypsum is pressed in the direction from the distal teeth to the medial ones. On the lower jaw - on the contrary. When taking an impression with plaster, complications are possible: vomiting, soft tissue injury, tooth extraction, tooth fracture, dislocation of the lower jaw, jaw fracture, aspiration.

DENTOL-S Dentol-S is an impression material based on zinc oxide guaiacol system and consists of two pastes - guaiacol paste No. 1 (red) and zinc oxide paste - No. 2 (white). PURPOSE: Dentol-S is used to take high-precision impressions of the oral cavity. It is especially advisable to use Dentol-S when obtaining accurate impressions from edentulous jaws, when the oral mucosa is loose, with a functional design of their edge. The presence of single teeth is not an obstacle to obtaining this kind of impressions. PROPERTIES: Before structuring, Dentol-S has great plasticity, and in the first minutes after structuring - some elasticity. This property allows you to get impressions that accurately reflect the tissues of the prosthetic bed and avoid delays and distortions when removing the impression.

REPIN Repin is an impression material based on the zinc oxide eugenol system, consisting of two pastes - eugenol paste No. 1 (brown) and zinc oxide No. 2 (white). PURPOSE: the paste has proved itself in practice as an excellent mass for obtaining impressions of large surfaces of the mucous membrane, especially for impressions of edentulous jaws. Repin can also be used for temporary fixation of fixed dentures. PROPERTIES: zinc oxide eugenol paste has elasticity, which allows to obtain prints with a distinct image of microrelief, and the ability to harden in a humid environment. The correct consistency of the paste eliminates the possibility of forced compression of soft tissues and allows you to flawlessly process prints according to the individual characteristics of the patient.

ALGINATE MASSES Alginates are flexible impression materials. The raw material for the production of alginates is seaweed. The powder of alginate material contains sodium or potassium salts of alginic acid (15%), which are highly soluble in water, calcium sulfate (about 12%), sodium phosphate - a setting retarder (2%). Inorganic fillers (talc, zinc oxide) determine the viscosity of the material and its stability after hardening and make up the bulk of the powder (70%). Additionally, the alginate powder contains a small amount of coloring agents, flavoring agents, fragrances and fluorine compounds to enhance the strength of the surface of the plaster model.

Properties of alginates The viscosity of the kneaded alginate material depends to a large extent on the amount of water added during kneading. Therefore, it is necessary to adhere to the proportions of water and powder that are proposed by the manufacturer. Detail Accuracy The accuracy with which alginate impression materials are able to convey details is determined by the size of the powder granules and the type of macromolecules formed. The accuracy limit for small objects is about 50 m (according to ISO 1563). This detail fidelity is not as good as that of silicone impression materials, so alginates should not be used to take impressions of working casts that will be used for inlays, crowns, and bridges.

Dimensional stability Water in the polymerized alginate is in an unbound form between macromolecules. Therefore, depending on the conditions under which the finished impression is stored, water can easily be absorbed by the material if there is too much of it, or the material can lose water and dry out. The accumulation or loss of water changes the original dimensions of the casts, so plaster models must be obtained immediately after taking the casts. Elasticity Due to the presence of a cross-linked structure of macromolecules, the polymerized alginate material has elasticity, which allows to obtain the display of areas with undercuts. However, this elasticity is even less than that of hydrocolloid impression materials. The alginate impression material fails at 50% pressure and at comparatively low tensile loads. Therefore, large undercuts, such as wide interproximal spaces and spaces under bridge pontics, must be isolated in the patient's mouth prior to taking an alginate impression. It is also necessary to remember that the layer of alginate between the teeth and the impression tray must be at least 5 mm thick. Plastic impression trays should not be used. This requirement is explained by the fact that the elastic deformation of the alginate during the removal of the impression will be so great that the original shape of the impression will not be completely restored and a permanent plastic deformation will remain.

Disinfection A problem with the disinfection of alginate impressions is that alginates can only be in an aqueous medium for a short time without significant water uptake and dimensional deterioration. However, studies show that the use of sodium hypochlorite (household bleach) provides effective disinfection of alginate impressions within minutes without compromising the quality of the impressions.

Hydrohum alginate Elastic alginate with fast setting setting time: 2 min 10 sec PROPERTIES - fast water absorption; - easy mixing; - homogeneous mass; - long-term preservation of casts

Orthoprint alginate Characteristics: Super-elastic alginate Fastest processing and setting time Pleasant vanilla scent to reduce gag reflex Yellow color Dust-free Advantages: Quick water absorption Easy mixing Homogeneous mass, smooth and compact surface Long-term preservation of impressions Setting time 1 minute 50 seconds

Upin Premium YPEEN PREMIUM Alginate impression material standard packaging 450 g in a bag For taking impressions in the manufacture of partial dentures, preliminary impressions in the manufacture of complete dentures (for the manufacture of individual trays), for taking impressions in orthodontic practice, impressions for the manufacture of workers models, temporary crowns and bridges. Easy to mix alginate impression material with optimum viscosity, short curing time, optimum working time, excellent detail transfer, good plaster compatibility.

Face alginate Clinical recommendations Chromatic three-phase alginate of reduced viscosity. It is recommended in the presence of a pliable mucous membrane. Suitable for beginners. Characteristics of Chromatic three-phase alginate: - Violet phase: mixing time - Red phase: processing time - White phase: oral administration Short processing and setting time Thixotropic Stiffness after gelation Chlorophyll aroma

Polyester masses are quite a promising group of impression materials. They contain various polyesters, plasticizers and inert fillers. Properties. The polymerization reaction proceeds according to the type of polyaddition, i.e., without the release of side substances. In this regard, they are distinguished by a very small linear shrinkage. Stable, however, not plastic enough. For mixing the main and catalytic masses, new automatic mixing systems of the Pentamix type (ЗМ / ESPE) are used, which prevent the formation of bubbles

Silicone impression materials The main advantages of Alphasil C-silicones: Working time varies depending on the amount of catalyst Low shrinkage percentage High precision and elasticity Impression shelf life - 1 week All materials are hydrophilic and thixotropic

Disadvantages: - Not ideal quality when taking impressions with retraction threads - They require careful manual mixing of masses and catalysts of different consistency - Difficulty in accurately dosing the catalyst, everything is "by eye" - It is impossible to cast models on the impression repeatedly - Sensitivity to moisture - hygroscopicity. - Low hydrophilicity - Insufficient adhesion to the tray - Possibility of toxic effect described in literature - No automatic mixing - Slightly excessive hardness of the base mass

The main advantages of Betasil A-silicones: Ease of mixing and precise dosing of mass and catalyst thanks to a 1:1 ratio Excellent hydrophilic and thixotropic properties of masses Elasticity and tensile strength Perfect recovery of shape after deformation Due to the high quality of the impression mass, the impression can be used repeatedly adjust the hardening time of the material depending on the temperature. The total running time varies from 2 to 4 minutes. Disadvantages: - Cannot be kneaded with latex gloves - A-silicones are slightly more expensive than C-silicones

Thermoplastic masses soften at a temperature of 50-70°C and become solid at an oral cavity temperature (37°C). n Thermoplastic materials do not accurately represent the details of the prosthetic bed. The relief of the mucous membrane on the print is displayed smoothed, because the mass has low fluidity. An accurate representation of the dentition cannot be obtained using thermoplastic mass due to its hardening after cooling. Therefore, when the teeth are tilted, the equators of the teeth are pronounced during removal, the impression is deformed.

Tiodent is a completely non-shrinking material, which makes it possible to keep impressions for a long time. The high elasticity of the impression mass before taking the impression and plasticity before vulcanization make it possible to obtain impressions that reflect the relief of the hard and soft tissues of the oral cavity. Sielast Benefits High impression elasticity. High print precision. Good shape recovery after deformation. Several models can be cast from one impression.

stay. Metal spoons after appropriate processing (sterilization) can be reused. They can be cast without perforations and with perforations for mechanical fixation of the impression material in the tray (Fig. 30).

Plastic spoons are intended for single use and are supplied in sealed (vacuum) packaging. They have different sizes and shapes, and are usually produced with perforations. The more varied the choice of spoons, the more opportunities the doctor has to take an impression. The shape and size of the impression tray is determined by the shape of the jaw, the severity of the edentulous alveolar part and other conditions that are reflected in the production of impression trays. So, for example, a set of 23 spoons for edentulous upper and lower jaws called Stock is presented by COE (USA) in the following types: round (8 pcs.), Rectangular (8 pcs.), Triangular (7 pcs.). Some firms produce spoons for edentulous jaws in sets, where there are 5 sizes for the lower and upper jaws.

Rice. 30. Standard metal spoons for edentulous upper and lower jaws

Making and using individual spoons

individual spoon- this is an impression tray designed to take the final impression and made in accordance with the anatomical and topographic features of the dentoalveolar system of a given patient. Materials for their manufacture can be divided into the following groups:

– wax (at present, individual wax spoons are not used, but hard spoons are preferred);

– cold polymerization plastics (the most common group);

– light-curing materials (are increasingly used);

- thermoplastics.

The combined use of materials is possible.

Such a spoon facilitates the view during fitting, makes it possible to see the places of compression of the mucous membrane and more clearly define the distal border (Fig. 32).

Rice. 31 . Individual spoon for the upper edentulous jaw Tiefziehhmaterial Erkorit

3.5 mm (Erkodent GmbH, Pfalzgrafenweiler)

Rice. 32. Functional spoon made of transparent material during fitting on the upper jaw

There are many methods for making individual spoons, but most of them, for one reason or another, are not used in practical healthcare. Techniques can be divided into direct, in which the doctor makes a spoon directly in the patient's mouth with an impression in one visit, and indirect (extraoral, laboratory) - with a preliminary model and the participation of a dental technician.

In recent years, preference has been given to laboratory methods for the manufacture of individual spoons, which in turn can be divided into:

- for manufacturing on a plaster model by palpation compression of self-hardening plastic in the pasty stage;

– method of compression molding of plastic, which involves the wax modeling of a spoon, the use of detachable molds and the use of polymerization techniques (high or low temperature);

– injection molding technique - the difference from the previous one is the use a syringe press and a special cuvette with sprue channels;

– vacuum pressing technique using special molds and blanks-plates of thermoplastic polymers of various thicknesses, which are crimped according to the model and cut along the boundaries;

– production from light-cured polymers (the plate is crimped according to the model and polymerized in a special box);

– technique for making spoons using bulk modeling technology - application polymer powder on the surface of the plaster model, followed by impregnation with a monomer liquid to saturation and polymerization in a pneumopolymerizer at 3 atm.

The method has become widespread direct manufacture

making an individual spoon from acrylic self-hardening plastic dough applied to a plaster model of the jaw (palpation method)

compression). However, it cannot be considered promising for the following reasons:

– an individual spoon is made from plastic dough, which is in the stage of stretching filaments, when significant deformations are observed that distort the surface macrorelief (the edges of the spoons in the manufacture of this method very often move away from the boundaries in the region of the transitional fold, which occurs due to linear shrinkage of the material

in during the exothermic polymerization reaction);

– evaporation of the monomer (methyl methacrylate), which has a high toxic-allergic effects, and prolonged contact with the skin of the hands of a dental technician does not improve human health;

– there is no clear repetition of the microrelief;

– polymerization process, the big disadvantage of which is a significant surface deformation and the formation of gas porosity.

However, along with the negative qualities of this technique, there are also positive ones. So, if it is necessary to use less fluid impression materials that do not allow obtaining the thinnest layers of impression material in the space between the tray and the mucous membrane, the use of this technique is fully justified. In this case, inaccuracies and minor deformations of the tray surface are relatively effectively compensated by impression materials (E. S. Kalivradzhiyan, E. A. Leshcheva, N. A. Golubev, T. A. Gordeeva, N. G. Mashkova, S. V. Polukazakov ). The disadvantages listed above can be eliminated by using

to study methods of compression or injection molding of self-hardening plastics in the production of individual spoons. The factors hindering the development of these techniques are the high consumption of investment and modeling materials, as well as significant time, energy and labor costs.

At present, the technique of manufacturing

making an individual spoon from light-curing polymers . They can be produced in the form of plates or in a block (Fig. 33).

Rice. 33. Plates of light-curing polymer

Based on the anatomical impression, a plaster model is made, on which the border of the future individual base spoon is drawn. A plate of non-polymerized plastic is taken and tightly crimped according to the model. The excess is cut off with a scalpel (Fig. 34, a). A handle is made from scraps and, if necessary, the edges of the spoon are thickened (Fig. 34, b). Then the model with a crimped spoon is placed in a special light-curing apparatus (Fig. 34, c). When the plastic is ready, the edges are polished with a carborundum head and cutter and notches are made for the labial frenulums and cheek folds.

Rice. 34. Method for manufacturing an individual spoon from light-cured polymers

Many authors consider the most effective technique for obtaining a functional compression impression using a plastic base spoon with wax bite rollers. Bite rollers on a rigid base allow you to get an impression under the control of masticatory pressure and achieve the most approximate picture of loading and compression of the mucous membrane by the base of the prosthesis (Fig. 35, 36).

Rice. 35 . Individual spoon for the upper jaw with a bite roller

Rice. 36. Individual tray for the lower edentulous jaw with bite pads and a handle for easy fitting and taking a functional impression

Some Western companies produce standard individual trays that allow you to simultaneously take an impression from the upper and lower jaws with registration of the central ratio of the jaws, for example, double plastic trays SR-Ivotrey from Ivoclar-Vivadent (Liechtenstein) (Fig. 37).

Rice. 37. Set of impression trays SR-Ivotrey

Detaks (Germany) produces a special SI-PLAST TRAYS set for taking impressions, which contains: 4 perforated plastic spoons of different sizes for the upper jaw and 4 perforated plastic spoons of different sizes for the lower jaw, 4 palatal templates, as well as 8 removable metal grips that are applicable for atrophied jaws (Fig. 38).

Fig.38. SI-PLAST TRAYS set

Method for obtaining an anatomical impression

To obtain an anatomical impression, it is necessary to choose the right standard metal or plastic spoon. Its shape and size are determined by the size of the jaw. For these purposes, a dental compass is used, which allows you to determine the distance between the ridges or their slopes in the lateral sections. When choosing a spoon, you need to take into account some anatomical features of the oral cavity. So, on the lower jaw, you need to pay special attention to the lingual side of the spoon, which should be made longer than the outer one in order to have

the ability to push deep into the soft tissues of the floor of the mouth. In addition to a properly selected impression tray, the impression material is of no small importance for obtaining a high-quality anatomical impression. The choice of material depends on the degree of atrophy of the alveolar processes and the alveolar part, the condition of the soft tissues, and the degree of mucosal compliance. So, with a slight uniform atrophy of the jaws, alginate impression materials and thermoplastic masses can be used. With severe atrophy of the jaws, it is recommended to use materials that allow you to move the tissues to half of their maximum mobility. In such cases, it is advisable to choose silicone and polyvinylsiloxane masses. With severe atrophy of the jaws, complicated by a “dangling comb”, it is necessary to take an impression without pressure with plastic alginate masses with high fluidity, low density and increased working time compared to alginates used in orthodontics or fixed prosthetics.

AT Currently, there are modern methods for obtaining anatomical impressions. They are used for minor atrophy of the jaws. This is a combined technique of taking anatomical impressions with hydrocolloid materials with alginates and simultaneous taking of impressions from both jaws, giving optimal results.

AT in especially difficult cases, such as complex jaw prosthetics, the most effective way to make a mass and obtain an impression can be considered to be obtaining a differentiated impression with two-component alginate masses. To do this, alginate is introduced into the syringe.

material of high fluidity, and in an impression tray of low fluidity. Using a syringe, the alginate mass is injected into the region of the transitional fold, frenulum and bands, the region of the midline of the hard palate, then the spoon with the impression material is inserted into the oral cavity.

Before the impression procedure, the mouth is rinsed with a weak antiseptic solution (potassium permanganate, chlorhexidine, Duplexol or PreEmp preparations). The corners of the patient's mouth are smeared with petroleum jelly or a special antiseptic cream, such as Viko-1 manufactured by Galenika (Yugoslavia). For good adhesion of the impression mass to the surface of the tray, it is recommended to pre-treat its edges with adhesive sprays or a special adhesive adhesive. The material is kneaded with a metal or plastic spatula in a rubber cup, on glass, waxed or coated paper, or in mechanical mixers. The impression mass prepared in accordance with the instructions is placed in the tray flush with the sides. Excess mass (material) smear the vault of the palate and the vestibule of the oral cavity in the region of the alveolar tubercles on the upper jaw or the lateral sections of the sublingual pro-

lands on the bottom. These are the most inaccessible areas for impression material. Air bubbles can form here, leading to gross impression defects. The spoon is inserted into the oral cavity with its left side, which pushes the left corner of the mouth. Then, with a dental mirror or a lingual spatula held by the doctor's left hand, the right corner of the mouth is pulled, and the spoon is in the oral cavity. It is centered, while the handle is set along the midline of the face. Then the spoon is pressed so that the alveolar part is immersed in the impression mass. In this case, first, pressure is exerted in the posterior sections, then in the anterior section of the jaw. This prevents the mass from flowing into the throat. Excess impression material moves forward. When squeezing out the mass in the area of the soft palate, it is carefully removed with a dental mirror. When taking an impression (especially of the upper jaw), the patient's head should be vertical or tilted forward. All this prevents the provocation of the gag reflex and the aspiration of the mass or saliva into the larynx and trachea. Holding the spoon with the fingers of the right hand, the doctor forms the vestibular edge of the impression with the left hand. At the same time, on the upper jaw, he grabs the upper lip and cheek with his fingers, pulls them down and to the sides, and then slightly presses them against the side of the spoon. On the lower jaw, the lower lip is pulled up, after which it is also slightly pressed against the side of the spoon. The lingual edge of the lower impression is formed by lifting and protruding the tongue. After the impression material has hardened, the impression is removed from the oral cavity. When evaluating the impression, they pay attention to how the space behind the maxillary tubercles, the retromolar space has woken up, whether the frenulums are clearly displayed, whether there are no pores, etc. The impressions taken from the patient's oral cavity are rinsed with a stream of running water for 1 minute. This simple action will reduce microbial contamination of the impression by approximately 50% and reduce the risk of hospital-acquired infection. Then the impressions must be immersed in a disinfectant solution. At the end of the procedure, they are taken out of the solution and washed with a stream of water for 0.5–1 min to remove residual disinfectant. With a chemical pencil on the impressions, the boundaries of future individual spoons are marked and transferred to the dental laboratory for their manufacture, where the technician casts the models. Transportation to the dental laboratory should not allow deformation and prolonged compression in order to avoid damage to the impression.

Obtaining an impression may be complicated by a gag reflex. To prevent it, you need to accurately select the impression tray. A long spoon irritates the soft palate and pterygomandibular folds. In the event of a gag reflex, elastic masses should be used, and in a minimal amount. Before taking an impression, it is useful to try on a spoon several times, accustoming the patient to it. During the procedure, the patient

The ent is given the correct position (a slight tilt of the head forward) and is asked not to move the tongue and breathe deeply through the nose. These simple techniques, as well as appropriate psychological preparation, make it possible in some cases to eliminate the urge to vomit. If, with an increased gag reflex, these measures do not give a result, special medical preparation has to be carried out. To do this, the mucous membrane of the root of the tongue, the pterygomandibular folds, the anterior soft palate and the posterior third of the hard palate are sprayed with a 10% solution of lidocaine (Hungary), legakain (Germany) or Peril spray (France) containing a 3.5% solution tetracaine hydrochloride. However, this may completely remove the protective gag reflex and lead to saliva leakage or aspiration of the impression material into the larynx. Small doses (0.0015–0.002 g) of the antipsychotic haloperidol administered 45–60 minutes before the impression procedure have a good antiemetic effect. As mentioned above, the impression is carried out sequentially - first from one jaw, and then from the other.

Complete fixation and stabilization of removable dentures on edentulous jaws is achieved if the borders of the base correspond to the transitional fold, the relief of the prosthetic bed is congruent and the inner surface of the base is congruent. Therefore, it is not enough to use only anatomical impression. Only when taking a functional impression, you can get a clear display of the macro- and microrelief of the mucous membrane and find out the exact boundaries of the prosthesis. For this, individual impression trays are used. For the manufacture of individual spoons, a good anatomical impression is needed, on which all parts of the prosthetic bed are revealed.

Fitting individual spoons

To take a functional impression, individual trays must be carefully fitted in the patient's mouth. Each functional test allows you to accurately capture the relief in a particular area of the prosthetic bed, create a marginal closing valve. Most often, educational publications describe the fitting technique using functional tests according to Herbst. Indications for the use of the Herbst technique are: the absence of atrophy of the alveolar processes and the orthognathic ratio of the edentulous jaws. These conditions are met by 10-15% of patients with complete loss of teeth.

According to this technique, after the introduction of an individual spoon into the oral cavity, the patient makes certain groups of movements, and if the spoon is displaced, then its borders are shortened in a certain place. Recently, it has been considered that functional tests are of great importance, however, they can be used to fit individual spoons (especially the lower one) with such accuracy as described in the Herbst method.

(Table 1), impractical due to the reduction of the boundaries of the spoons. It is believed that tests should be performed with a reduced range of motion, especially for the lower jaw.

Table 1

	Fitting of individual spoons according to the Herbst method


		violations of its fixation
		violations of its fixation
	Attaching a spoon to the upper jaw
	swallowing	Distal border along line A
	Wide mouth opening	Zone of maxillary tubercles and retromolar
		vestibular area
	Cheek suction	The vestibular surface on the right and left in the region
		buccal mucous cords
		The end of the table. one

		Correction zone of an individual tray in case of
		violations of its fixation
		violations of its fixation
	Lip pulling	Vestibular surface in the region of the frenulum
		upper lip
	Putting a spoon on the lower jaw
	swallowing	On the lingual side from the mucous tubercle to the
		ciliary-hyoid line
	Wide mouth opening	If the spoon is dropped from behind, then it is shortened
		from the vestibular side from the mucous tubercle to
		projections of the first molar, if the spoon is thrown
		is in the frontal section, then it is shortened with
		vestibular side between canines
	Run the tip of your tongue across	Along the maxillary-lingual line
	red border top and bottom

	Touch the tip of the tongue to	Lingual surface in the region of premolars
	cheeks with half-closed mouth
	Stick the tip of the tongue forward	Lingual surface in the region of the frenulum of the tongue
	towards the tip of the nose
	Pulling lips with a tube	Vestibular surface between canines

Fitting an individual spoon to the upper jaw. Particular attention is paid to the distal border of an individual spoon, which is recommended to be marked with a line in the patient's mouth before fitting the spoon. 1–2 mm distal to the blind holes (or line A) (Fig. 39).

functional impression It is customary to call an impression that reflects the state of the tissues of the prosthetic bed during any movements of the lips, cheeks, tongue. For the first time, the method for its preparation was developed by Schrott in 1864.

Impression classification.

The most popular classification of impressions according to E.I. Gavrilov. It was based on the following basic principles.

1. The principle of the sequence of laboratory and clinical techniques for the manufacture of prostheses. On this basis, prints are preliminary (indicative) and final. Preliminary impressions are taken with a standard spoon. They are used to cast diagnostic models of the jaws, which allow studying the relationship of the dentition, alveolar ridges of the edentulous jaws, the relief of the hard palate and other features that are important for making a diagnosis, drawing up a plan for preparing the oral cavity for prosthetics and the plan for prosthetics itself. The same technique allows you to determine approximately and produce individual spoon . A working model is cast from the final impressions.

2. A method of designing the edges of the impression, allowing the prosthesis to have a closing circular valve, providing one or another degree of its fixation. Accordingly, there are anatomical and functional impressions .

According to the method of decorating the edges of E.I. Gavrilov subdivides functional impressions formatted with:

A) passive movements;

B) chewing and other movements;

C) functional tests.

between anatomical and functional impressions no clear boundary can be drawn. As such, there are no purely anatomical impressions. Receiving an impression with a standard spoon, when forming its edge, functional (though not sufficiently substantiated) samples are always used. On the other hand, functional impression represents a negative display of anatomical formations (palatine ridge, alveolar tubercle, transverse palatine folds, etc.) that do not change their position during movements of the lower jaw, tongue and functions of other organs. Therefore, it is perfectly natural that functional impression has signs of anatomical, and vice versa.

3. The degree of pressure or the degree of squeezing of the mucous membrane.

According to the degree of its squeezing, functional impressions are divided into:

1) compression or obtained under pressure, which can be arbitrary, chewing, dosed;

2) differentiated (combined);

Individual spoons.

Under any clinical conditions, only functional impression individual spoon.

Customized spoons can be made from:

1) metal (steel, aluminum) by stamping;

2) plastics:

A) basic (fluorax, ethacryl, yarocryl) polymerization method;

B) fast-hardening (redont, protacryl) by free molding;

c) standard plastic plates AKR-P;

D) light-curing plastic;

3) solar-cured materials with polymerization in special chambers or using a solar lamp;

4) thermoplastic impression masses (Stens);

5) wax.

individual spoons are made in the laboratory or directly with the patient.

Making an individual spoon from plastic in the laboratory.

In this case, an anatomical cast is taken with a standard spoon and a plaster model is cast on it. On the model, the dental technician draws the boundaries of the future individual spoon.

On the upper jaw, the border of the spoon runs from the vestibular side along the transitional fold, not reaching the deepest point of its arch by 1-2 mm. On the distal side, it overlaps the maxillary tubercles and runs along the line "A" behind the palatine fossae by 1-2 mm.

On the lower jaw, the border of the spoon runs from the vestibular side along the transitional fold, not reaching the deepest point of its arch by 1-2 mm, while bypassing the bands and frenulum of the lip. In the retromolar region, it is located behind the mucous tubercle, overlapping it by 1-2 mm.

On the lingual side, the border of the spoon overlaps the area corresponding to the retroalveolar region (muscleless triangle), not reaching the deepest place of the sublingual space by 1-2 mm and bending around the frenulum of the tongue.

From the foregoing, it can be seen that both on the upper and on the lower jaw individual spoon border passes 2-3 mm less than the boundaries of the prosthesis. This is done in order to leave room for the impression material. The displaced impression material forms the edges of the impression. And, conversely, the distal borders of the tray should be larger than the borders of the prosthesis so that the anatomical formations that are the guidelines for the distal edge of the prosthesis are well imprinted when the impression is taken.

After applying the borders, the dental technician covers the model with Isokol insulating varnish and proceeds to making a custom spoon from quick-hardening or basic plastic.

For making a custom spoon from quick-hardening plastic, the required amount of material is kneaded to the dough-like stage and a plate is made from it in the shape of the upper or lower jaw, which is crimped on the model along the outlined boundaries. Then, from small pieces of plastic "dough", a handle is made perpendicular to the surface of the spoon, and not tilted forward. This position of the handle will not interfere with the design of the edges of the print. If on the lower jaw the alveolar part is significantly atrophied and the spoon turned out to be narrow, then the handle is made wider, almost to the premolars: with such a handle, the doctor's fingers will not deform the edges of the impression when they hold it on the jaw

After the plastic has hardened (10-15 minutes), the spoon is removed from the model and processed with cutters and carborundum heads ( individual spoon do not polish), making sure that the edges of the spoon correspond to the boundaries marked on the model. The thickness of the edge of the spoon must be at least 1.5 mm, because. with a thinner edge, it is difficult to obtain the volume of the edge of the print.

individual spoon can be made from the base plastic by polymerization. To do this, the heated wax plate is pressed tightly over the model, giving it the shape of an impression spoon, the excess wax is cut off with a spatula along the marked boundaries. The wax form of the spoon is plastered into the cuvette in the reverse way and the wax is replaced with plastic.

When making a spoon from AKR-P plastic, standard plates are softened in hot water and crimped according to the model. The excess is cut off with scissors after softening the corresponding area. The handle is made from scraps of material and glued to the spoon with a hot spatula (plastic melts and welds from heat).

Individual plastic spoons are hard spoons. They can be used, as well as thermoplastic spoons, for taking compression impressions.

Advantages and disadvantages of individual plastic impression trays. Plastic spoons are rigid, do not deform in the oral cavity, but, like any laboratory-made spoons (in two visits), they require subsequent correction in the oral cavity. In addition, spoons made in this way give a modified image of soft tissues, since they are compressed and stretched during the anatomical impression.

Wax individual spoons for the upper and lower jaw

Personalized wax spoons can be made both in the laboratory and directly in the oral cavity. Wax spoons according to the CITO method are made in one visit directly on the jaw of the prosthetist. Such spoons are more accurate than individual ones made from an anatomical cast, because they display the soft tissues of the prosthetic bed at rest. The disadvantage of such spoons is that soft wax is deformed during fitting in the oral cavity and when taking an impression (it cannot withstand pressure), therefore, a wax spoon can only be used to remove decompression impressions. individual spoons , regardless of what method and what material they were made of, should be fitted in the oral cavity. A properly fitted spoon sticks to the jaw and does not lag behind it with the movements of the lips and cheeks. In our country, widespread method of fitting individual spoons using Herbst functional tests.

Five samples are used on the lower jaw:

1) swallowing and wide opening of the mouth;

2) movement of the tongue to the sides along the red border of the upper and lower lips;

3) touching the tip of the tongue to the cheeks with a half-closed mouth;

4) movement of the tip of the tongue forward beyond the lips towards the tip of the nose;

5) stretching the lips forward.

Three samples are used on the upper jaw:

1) wide mouth opening;

2) suction of the cheek;

3) displacement of the lips forward (stretching).

Getting a functional impression.

After fitting an individual spoon, they begin to obtain a functional impression.

Taking an impression consists of the following steps:

1) fitting of an individual spoon;

2) applying the impression mass on a spoon;

3) the introduction of a spoon with a mass into the oral cavity;

4) forming the edges of the impression and conducting functional tests;

5) removal of the impression and its evaluation.

It should be taken as a rule that functional impression, providing good fixation of the prosthesis, can only be obtained if the anatomical impression reflects all the structures of the prosthetic field and some functional features of the tissues surrounding the prosthetic bed. Upon receipt functional impression they are only specified.

There are unloading or decompression and compression impressions.

Usually, the value of a compression or unloading impression is associated with the fixation of the prosthesis and its effect on the mucous membrane of the prosthetic bed. However, the value of one or another technique for taking an impression is determined by the influence of the prosthesis on the course of the process of atrophy of the alveolar process.

Unloading (decompression) impressions obtained without pressure or with minimal pressure of the impression mass on the tissues of the prosthetic bed.

The disadvantage of the unloading impression is that the buffer zones of the hard palate are not subjected to compression, and all the pressure from the prosthesis is transferred to the alveolar process, increasing its atrophy.

When receiving a decompression impression, the impression material must reflect without distortion every detail of the oral mucosa so that the microrelief of the prosthesis base exactly matches the surface structure of the prosthetic bed. Therefore, such impressions can be obtained only with the help of impression masses that have a high fluidity and do not require much effort to remove the impression. Such masses include low viscosity silicone pastes: exaflex, xanthoprene, alfazil, as well as zinc oxide eugenol pastes. The impression obtained using liquid gypsum (according to Brahman) usually provides just such a perception of the relief of the surface of the tissues of the prosthetic bed. Some authors believe that if several holes are drilled in the impression tray to drain excess impression material, then the pressure of the impression mass on the mucous membrane can be reduced.

It is known that the fixation of prostheses made from decompression impressions is weak, but they can be used if there are certain indications.

These indications include:

1) significant or complete atrophy of the alveolar processes and mucous membrane;

2) increased sensitivity of the mucous membrane;

3) uniformly pliable mucous membrane of the prosthetic bed.

Compression impressions designed to take advantage of mucosal compliance, so they are removed at high pressure to compress the buffer zones. When talking about a compression impression, they first of all mean the compression of the vessels of the prosthetic bed. The decrease in tissue volume, its vertical compliance are directly dependent on the degree of filling of the vascular bed. The use of compression impressions is recommended in the presence of a loose mucous membrane with good compliance.

A prosthesis made according to a compression impression does not load the alveolar ridge; outside of chewing, it relies only on the tissues of the buffer zones, like on pillows. When chewing under the influence of chewing pressure, the vessels of the buffer zones are emptied of blood, the prosthesis settles somewhat and transfers pressure not only to the buffer zones, but also to the alveolar part. Thus, the alveolar process is unloaded, which prevents its atrophy.

A prosthesis made according to a compression impression has a good fixation, because the pliable mucosa of the valvular zone is in closer contact with the edge of the prosthesis.

The compression impression is taken under continuous pressure. , providing compression of the vessels of the mucous membrane of the hard palate and their emptying. To obtain such an impression, certain conditions must be met:

1) you need a hard spoon;

2) the impression must be taken with a low flow mass or a thermoplastic mass;

3) compression should be continuous, stopping only after the mass hardens. Continuity can be ensured by hand effort (voluntary pressure). But it is more convenient and correct to take a compression impression under the chewing pressure of the muscles that lift the lower jaw, i.e. under bite pressure, which is created by the patient himself, or with the help of special devices that allow you to create a strictly defined pressure (metered) taking into account the individual characteristics of the tissues of the prosthetic bed and chewing muscles.

For obtaining a functional impression use thermoplastic masses, such as Dentofol, Otrocor, Orthoplast, etc.

The convenience of using thermoplastic masses is explained by the following properties:

1) they have an extended plasticity phase, which makes it possible to carry out functional tests necessary to obtain a high-quality impression;

2) during the removal of the impression, they always have the same consistency;

3) they do not dissolve in saliva;

4) evenly distribute pressure;

5) allow you to repeatedly enter the impression into the oral cavity and carry out correction, because new portions of the mass merge with the old portions without deforming the impression.

However, thermoplastic masses have certain disadvantages. These include: inaccurate print due to low fluidity; deformation in the presence of retention points. When cooled with water, they harden unevenly and may deform when removed from the oral cavity.

It should be recognized that when using the above methods of obtaining an impression, in some cases it is not possible to provide a complete functional reflection of the prosthetic field. The tissues of the prosthetic field and the active muscles surrounding it are not the same in relief, relative volume, physiological status during chewing or talking, as well as during the day. The physical and emotional state of a person also has a great influence on the state of the prosthetic bed and the muscles surrounding it. Whatever method of taking the impression is used, further adaptation of the prosthesis base to the tissues of the prosthetic field, the ratio of the dentition and the force of masticatory pressure, as well as the adaptation of the patient and the fitting of the prosthesis for a certain time, is necessary.

The wide variety of clinical conditions encountered for prosthetics necessitates the use of a differentiated impression. One should proceed from the general position that there is no single method shown in all cases. In this regard, the method of obtaining an impression in each specific case must be chosen taking into account the patient's age, constitutional and individual characteristics of the jaw tissues, i.e. in all cases, a differentiated approach is needed. In cases where the tissues of the prosthetic bed in different areas are not the same in their relief and structure, the biophysical properties of each of the elements of the prosthetic bed should be taken into account. When taking an impression, tissues with pronounced spring properties should be under greater load, while tissues of unloaded zones (in the region of the torus, incisive papilla, etc.) should not be excessively loaded.

Selective pressure on the underlying tissues, depending on their anatomical and functional features and biophysical properties, may be important in connection with the need to prevent premature atrophy of the soft and bone tissues of the edentulous jaws by redistributing the masticatory pressure of the prosthesis base.

Therefore, depending on the anatomical and physiological features of the prosthetic bed, it is possible to obtain a display of the mucous membrane in various functional states. At the same time, unloading casts are recommended to be obtained with a thin, atrophic and excessively pliable ("dangling" comb) mucosa. Compression casts are indicated for loose, well-compliant mucosa. The best effect can be achieved only by using differentiated casts obtained with varying degrees of compression of the mucous membrane, taking into account its compliance in different parts of the prosthetic bed.

Requirements for a functional impression:

1) have an accurate and clear imprint of the surface of the mucous membrane of the prosthetic bed without areas and pores washed out by saliva;

2) to have a uniform thickness of the edge and the layer of impression material of the bases of the gaps of the spoon;

3) have an accurate display of the "A" line and blind pits;

4) the edges of the print must be smooth and rounded;

5) the entire impression must be removed from the oral cavity.

Casting of working models.

After receiving the impression, they begin to evaluate it: they check whether the material is pressed in any areas, whether the edges are well-formed, what is their volume. Air pores are not allowed. Then the suction force of the impression is determined. To do this, an impression is introduced into the oral cavity, pressed against the prosthetic bed, and by the handle of the spoon they try to tear it away from the bed. If this is difficult, then this means that the fixation is good. In the event that all requirements are met, the impressions are transferred to the laboratory for further work.

To prevent violation of the valve zone on the model during its opening, the edges of the imprint should be edged. It is carried out as follows. A strip of wax 2-3 mm thick and 5 mm wide is layered 3-5 mm below the edge of the impression. After that, the model is cast in the usual way. The dental technician, cutting off the model, removes excess plaster only within the edging, thereby not violating the sections of the mucous membrane of the transitional fold, in which the edge of the impression was placed. After receiving the model, the wax is removed, and along its edge, a clear functionally designed border and a volumetrically reproduced valve zone remain on the model. If the integrity of the transitional fold is violated, modeling the edge of the prosthesis in accordance with the valve zone becomes impossible, because the marginal closing valve will have defects, which will lead to a violation of the fixation of the prosthesis.

The manufacture of plaster models of edentulous jaws is slightly different from the manufacture of those for removable dentures with partial defects in the dentition. Models with edentulous jaws are specially engraved.

Existing tubercles and nodules are removed from plaster models with a spatula. They are formed from the presence of small bubbles on the surface of the cast. After a general check, the model of the upper jaw is prepared for the creation of a peripheral valve on the palatal surface.

A small layer of gypsum 0.5-1.0 mm deep and of various widths is engraved with a spatula in the transition area of the hard palate into the soft palate. Such an engraving of the model leads to the formation of an elevation at the border of the prosthesis, which is immersed in a pliable tissue. The pressing of soft tissues on the valve zone corresponds to the creation of a palatal valve for the prosthesis on the upper jaw.