Making an individual impression tray. Making and using individual spoons

The invention relates to medicine, namely to orthopedic dentistry, and can be used in clinical practice for the manufacture of individual spoons of both jaws for prosthetics with full removable plate prostheses. For upper jaw first, a plastic plate is made - a template, according to the shape of which the substrate is bent from a metal plate with a polyvinyl chloride double-sided coating, the palate is formed, for which the heated base wax plate is cut to the shape of the inner edge of the substrate bead and the plate is poured to the edge of the substrate bead with heated wax, and the alveolar substrate is put on the alveolar the process of the upper jaw, the outer edge of the bead of the fitted substrate is pasted over with sprue wax, the posterior 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 onto the alveolar ridge of the patient's upper jaw and the sides are processed using functional tests, then transferred into an individual spoon, for which a thin layer of the base silicone impression mass is covered with the inner surface of the substrate, the substrate is fitted onto the alveolar ridge of the upper jaw and functional tests for processing the silicone mass at the edge of the sides of the substrate, and after vulcanization of the impression mass, an individual spoon for the upper jaw is obtained. For lower jaw first, a plastic plate is made - a template, according to the shape of which the substrate is bent out of a metal plate with a polyvinyl chloride double-sided coating, fitted onto the alveolar ridge of the patient's lower jaw, the edge of the side of the substrate is pasted over with sprue wax and re-fitted on the alveolar ridge of the lower jaw, while functional tests are performed then the substrate is transferred into an individual spoon, for which the inner surface of the substrate is covered with a thin layer of the base silicone impression mass, it is attached to the alveolar ridge of the lower jaw and functional tests are carried out to process the silicone mass at the edge of the substrate edges, and after vulcanization of the impression mass, an individual spoon is obtained for the lower jaw. The technical result is the ability to accurately correct and fit the substrate directly in the patient's oral cavity, which leads to the exclusion of the stages of taking preliminary anatomical impressions, casting models from plaster and making individual plastic spoons for them, thereby reducing the number of visits and reducing the labor intensity of the process of making individual spoons ...

The invention relates to medicine, namely to orthopedic dentistry, and can be used in clinical practice for the manufacture of individual spoons of both jaws for prosthetics with full removable plate prostheses.

There is a known method of making an individual spoon from wax directly in the oral cavity, followed by obtaining from it a working functional cast, developed at CITO GB Brakhman and ZV Kopp (V.Yu. Kurlyandsky. Orthopedic dentistry. - M., Medicine, 1968, p. 349.). However, the wax spoon in the mouth under the influence of temperature does not withstand excessive pressure, the resulting impression is inaccurate.

A known method is 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 resulting model, with which functional impressions are taken, then working models are cast, according to which wax bases with occlusal rollers and determine the height of the lower part of the face and the central ratio of the jaws (Doinikov AI, BV Svirin. Obtaining a functional impression of the edentulous lower jaw and the design of prostheses with sharp degrees of atrophy of its alveolar part. Guidelines, M., 1981) The disadvantage of this method is its significant labor intensity.

There is a known method of using a special set of spoons for edentulous jaws (SR ivotrey, universal & spezial spoons (Ivoclar firm), intended for simultaneous taking of indicative impressions from both jaws with the mouth closed ("Impression materials in dentistry" edited by TI Ibragimova, N.A. Tsalikova, pp. 40-42) During the taking of the impression, the height of the lower part of the face is recorded, however, this method cannot be used to use the obtained impressions for taking functional tests.

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

The closest, according to the authors, analogue (prototype) is a method of obtaining individual spoons from self-hardening plastics using wax compression matrices (Optimization of the technique for taking functional impressions from edentulous jaws. BP Markov, ES Iroshnikova, V.Yu. Kabanov / Tutorial. - MGMSU, 2004). For the manufacture of matrices on auxiliary plaster models, the boundaries of the trays 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 maxillary-hyoid line by no more than 1 mm. The compression matrix for the upper jaw is made of two layers of base wax, for the lower one - of three. A layer of self-hardening plastic is applied to the inner surface of the matrix cooled in water, squeezed under pressure, the boundaries of the spoon are specified using functional tests. The disadvantages of the prototype include the complexity and laboriousness of the technology. Since the spoon is prepared according to an auxiliary plaster model cast in an anatomical impression taken from the edentulous jaw with a standard spoon, this leads to mucosal delays and inaccuracies in the transmission of anatomical features.

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

The proposed method of manufacturing an individual spoon using the example of the upper jaw is as follows. A plastic plate is made - a template for the upper jaw. In the shape of the template, a substrate is bent from a metal plate with a polyvinyl chloride double-sided coating (PE-X / Al / PE-X), which has good adhesion to both wax and the impression material. At the ends of the substrate, dovetail incisions are made 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 bead of the substrate and the plate is poured to the edge of the bead of the substrate with heated wax. The substrate is fitted on the alveolar process of the upper jaw, the outer edge of the bead of the fitted substrate is pasted over with sprue wax with a diameter of 2.5-3.0 mm, the posterior section of the substrate in the region of the upper jaw tubercles is cut with scissors and pasted over with sprue wax heated on a burner. The support is fitted onto the alveolar ridge of the patient's upper jaw and the sides are processed using functional tests. To transfer the substrate into an individual tray, the inner surface of the substrate is coated with a thin layer of a base silicone impression mass. The backing material provides good adhesion to the silicone impression material. The substrate is fitted onto the alveolar ridge 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 material, an individual spoon for the upper jaw is obtained.

When making an individual spoon for the lower jaw, first, a plastic plate is also 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 its refinement is carried out. The substrate is fitted onto 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 frenulum and cords. The edge of the bead of the substrate is pasted over with sprue wax and reattached to the alveolar process of the lower jaw, while functional tests are carried out, in which the beads of the substrate are processed with the mimic and chewing muscles of the lips and cheeks. Then the substrate is transferred into an individual spoon, for which the inner surface of the substrate is coated with a thin layer of the base silicone impression mass. Next, the substrate is fitted onto the alveolar ridge 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 spoon for the lower jaw is obtained.

The proposed method for making 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 oral cavity, which leads to the exclusion of the stages of taking preliminary anatomical impressions, casting models from plaster and making individual plastic spoons based on them.

3. The backing material has good adhesion to wax and impression material, which eliminates the need for bonding systems. This allows one-stage production of occlusal wax rolls on an individual spoon, with the help of which the height of the lower part of the face is determined and the central ratio of the jaws is fixed. Therefore, one more stage is excluded (i.e., the patient's visit to the dentist) - determination of the height of the lower part of the face and fixation of the central ratio of the jaws using wax bases with occlusal wax rolls.

4. After special treatment of the wax occlusal rolls located on the crests of the individual trays obtained, according to the Christensen phenomenon, possibly by adding a thin corrective layer of silicone impression mass (spidex cream), to obtain accurate functional impressions 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 bent from a metal plate with a polyvinyl chloride coating, the formation of the palate, for which the heated base wax plate is trimmed to the shape of the inner edge of the substrate bead and the plate is poured to the edge of the substrate bead heated waxing, fitting the substrate to the alveolar ridge of the upper jaw, gluing the outer edge of the bead of the fitted substrate with sprue wax, trimming the posterior part of the substrate in the area of \u200b\u200bthe upper jaw tubercles and gluing it with sprue wax, attaching the substrate to the alveolar ridge of the patient's upper jaw, processing the functional samples of the substrate using , transfer of the substrate into an individual spoon, for which the inner surface of the substrate is covered with a thin layer of the base silicone impression mass, the substrate is fitted onto the alveolar ridge of the upper jaw and functional tests are carried out for processing the silicone masses at the edge of the sides of the substrate, obtaining an individual spoon for the upper jaw after vulcanization of the impression material, as well as the following signs - making 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 PVC coating, fitting it onto the alveolar ridge of the lower jaw the patient, gluing the edge of the substrate bead with sprue wax, fitting the substrate onto the alveolar ridge of the lower jaw with functional tests, transferring the substrate to an individual spoon, for which a thin layer of the base silicone impression mass is covered with the inner surface of the substrate, fitted onto the alveolar ridge 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, in the known solutions were not found, which allows us to conclude that the proposed solution meets the criterion m "novelty" and "technical level".

When making an individual tray for the lower jaw, a groove was made from a metal plate with a thickness of 2.7 mm with a PVC double-sided coating in accordance with a plastic template for the lower jaw. The lingual side of the backing piece is leveled with the help of cramps and, as a result, it is made flat from a semicircular one. Examining the alveolar processes of the oral cavity, the doctor determines their width, height, notes the severity of the bridles and forms a substrate from the above-described metal-polymer blank right next to the chair. Places for bridles and straps are cut out using a tip with a carborundum disc. The cut edge of the backing 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 with the help of crampon forceps is easily bent in the shape of the patient's alveolar process. 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 backing board is processed with a silicon carbide 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 alcohol lamp and the support 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 MGMSU method. In places where there is a highly malleable mucous membrane of the alveolar ridge and dangling mucous membrane, in these projections the substrate is perforated using a carbide cylindrical bur No. 3.

A basic soft silicone impression mass (optasil, speedx) is placed in the fitted individual substrate. The mass is laid in a thin, even layer along the inner surface of the substrate, introduced into the patient's oral cavity and located on the alveolar process along the specified boundaries, after which functional movements of the lips and cheeks are performed again. After vulcanization of the impression material, 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 poured onto the spoon along this mark

The individual spoon for the upper jaw is made in a slightly different way. The initial stage of fabrication of the metal-polymer base for the upper jaw is the same as for the lower one. The difference is that at the ends of the substrate with dental scissors, incisions are made with a length of 8-10 mm 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 backing board is also processed with a silicon carbide stone, glued with a 3 mm thick wax flagellum, the heated backing is inserted into the patient's mouth and located on the upper jaw. The patient is asked to perform a series of functional movements developed according to the MSMSU method for the upper jaw.

As well as on the individual support fitted on the lower jaw, on the fitted support for the upper jaw in places of the pliable and loose mucous membrane, as well as in the area 15 14|24 25 teeth are perforated with a carbide cylindrical bur No. 3. A thin layer of silicone base impression mass (optasil, speedx) is applied to the substrate and it is inserted into the patient's oral cavity and located on the upper jaw. In this case, the patient is asked to repeat the functional movements until the impression mass is completely vulcanized. 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 resulting spoon.

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

Individual trays with functional casts and occlusal wax rolls 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. Articulating surfaces of wax occlusal rollers are processed according to the Christensen phenomenon. On the upper occlusal roller, grooves are made in the area 16 15|25 26 teeth.

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

Occlusal roller on the lower individual tray in the area with 16| by |26 cut 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. The spoons are removed from the oral cavity, cooled and the occlusal ridges are separated with a spade. Then the spoons are re-inserted into the oral cavity and the central ratio of the jaws is monitored again. The corresponding markings are made on the upper and lower occlusal rollers. The spoons are removed from the mouth. Functional casts taken from the upper and lower jaws are used to cast the jaw models from super plaster.

Patient K., age 72, complained of poor chewing of food, upset from the gastrointestinal tract, impaired diction. Two and a half months ago, full removable plate prostheses were fitted to her in the Ivanovo polyclinic. The patient has been using such prostheses for 20 years. She can't get used to the latest dentures. Multiple denture corrections do not bring relief. Can only chew soft food, harder food causes soreness. Recently, there have been pains in the epigastric region, a feeling of heaviness, belching after eating. When talking, the patient swallows saliva, hissing sounds skip.

When examining the oral cavity, there is an average uniform atrophy of the alveolar process of the upper jaw (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.) Mucous membrane of the oral cavity and alveolar processes edematous and hyperemic, especially in the area of \u200b\u200bthe tubercles of the upper jaw and in the retromolar areas 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-tubercular contacts. On palpation, the prosthesis was balanced on the alveolar ridge of the lower jaw; slight balancing was observed in the prosthesis fitted to the upper jaw.

The patient was offered to make new prostheses according to the above-described alternative method, having previously treated the oral mucosa. After fulfilling the recommendations, the patient came to an appointment and on the first visit, according to the shape of the alveolar processes of the upper and lower jaws, templates were made of PVC plastic with a thickness of 0.8 mm. On them, substrates for the upper and lower jaws were made from a metal plate with a polyvinyl chloride double-sided coating (PVC material). In the patient's oral cavity, they were fitted onto the alveolar processes and, using a silicone impression mass, the spidex cream was transferred into individual trays. Then, occlusal wax rollers were poured 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 rollers was treated according to the Christensen phenomenon and with the help of a silicone impression mass, “spidex” cream, simultaneously functional impressions were taken at the moment of physiological movements of the lower jaw with the jaws closed.

Then the patient was registered with the central ratio of the jaws and the work was transferred to the dental laboratory. Models were made from super plaster casts, which were installed in the average position of the interframe space of the articulated-ellipse articulator, and fitted to the articulator frames. With the help of a special device, the artificial teeth were set on the wax base of the upper jaw model. The setting of the teeth on the wax base of the lower jaw model was made along the occlusal surface of the dentition, located on the wax base of the lower jaw model.

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

At the third visit, the patient was fitted with full removable plate prostheses for the upper and lower jaws. The contact density of the occlusal surfaces of the dentition was checked using Bausch maps. The sliding of the occlusal surfaces of the dentition was checked during sagittal and transverse movements of the lower jaw. Two super contacts were identified, which were removed using a spherical bur.

A week later, the dentures were re-corrected. A small namin was present in the retromolar region of the alveolar ridge of the lower jaw on the lingual side on the right; correction was performed with a carborundum head. After that, no prosthetic corrections were performed. Diction improved, with good chewing of food, pain in the epigastrium disappeared.

A method of manufacturing individual spoons for the upper and lower jaws, characterized in that for the upper jaw, first, a plastic plate is made - a template, according to the shape of which the substrate is bent from a metal plate with a double-sided PVC coating, the palate is formed, for which the heated base wax plate is cut in the shape of the inner the edges of the side of the substrate and the plate is poured to the edge of the side of the substrate with heated wax, the substrate is fitted onto the alveolar ridge of the upper jaw, the outer edge of the side of the fitted substrate is pasted over with sprue wax, the posterior part of the substrate in the region of the tubercles of the upper jaw is trimmed with scissors and pasted over with heated in a burner the moldings on the alveolar ridge of the patient's upper jaw and sides are processed using functional tests, then the substrate is transferred to an individual spoon, for which the inner surface of the substrate is covered with a thin layer of the base silicone impression mass, the substrate is pulled out onto 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, and after vulcanization of 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 out of a metal plate with a polyvinyl chloride double-sided coating, fitted onto the alveolar ridge of the patient's lower jaw, the edge of the side of the substrate is pasted over with sprue wax and re-fitted to the alveolar ridge, while holding the lower jaw functional tests, then transfer the substrate into an individual spoon, for which a thin layer of the base silicone impression mass is covered with the inner surface of the substrate, fitted onto the alveolar ridge 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 spoon for the lower jaw.

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Individual impression trays are designed to obtain functional impressions during prosthetics with partial and full removable plate prostheses.

For individual spoons, basic, quick-hardening plastics are used, as well as polystyrene.

The technology of an individual spoon depends on the material used:

When applying base plastic a wax base is prepared on the jaw model. Subsequently, the model is gypsum in a cuvette, and the replacement of wax with plastic is carried out according to the generally accepted technology. The time required for this method is 2.5-3 hours;

The use of a fast hardening resin consists of carrying the polymer-monomer composition directly onto a plaster cast of jaw, coated with an insulating varnish. A portion of the plastic dough is pre-rolled to a uniform thickness. Then polymerization is carried out in a hydro-polymerizer. The orthopedist-dentist or his assistant can make an individual spoon on their own. The time spent using this type of plastics is 40-50 minutes;

When using polystyrene, the plaster model of the jaw is wrapped around it in a thermal vacuum apparatus, the principle of which is to heat the polymer plate with a thermoelement and create a vacuum in the working chamber of the device using a built-in pump. As an example, we can name a small-sized tabletop apparatus Erkoform RVE (Erkodent, Germany), in which, in addition to the thermal vacuum production of individual impression trays from special polymer plates (round - German-made, square - American-made), they create therapeutic and prophylactic mouth guards (for whitening and fluoridation of hard dental tissues), protective mouth guards (for athletes), as well as temporary crowns;

In the case of using standard light-curing plates (for example, Individual Lux and Profibase, manufactured by Voko, Gemania), the latter are subjected to appropriate processing with special devices.

Fast-hardening plastic Karboplast (Ukraine) contains the plasticizer dibulphthalate. The material consists of a powder and a liquid, mixing which in propori 3: 1 forms a dough that polymerizes within 6-10 minutes.

Durakrol (SPS Dental, Czech Republic) is a two-component methacrylic injection molding plastic containing a mineral filler that hardens on the basis of chemical initiation in the absence of heating.

For individual spoons, the company "Hereus Kulzer" (Germany) has developed the following materials:

Plastic Palavit-L;

Palatray-LC and Paladisk-LC are ready-to-use light-curing plates. A device for the light polymerization of plastics is used for them.

Megatray is a light-curing material from Megadenta (Germany) for individual impression trays. It is a ready-to-use material that does not require mixing, produced in the form of plates in the shape of the upper and lower dentition, in two colors - pink and transparent with a gray-blue tint.

In addition, for this purpose, special acrylic plastics are used Tray (Condulor), Formtprey (Kerr, USA), Individual (Voko, Germany), MulypiTrai (ESPE, Germany), Ostrom ( firm "JiSi", Japan), etc.

Standard plate blanks for spoons are also produced: AKR-P, Kavex (Austria), Tessex (Spofa Dental, Czech Republic), etc. However, due to the inaccuracy and inconvenience of use, standard plates lose competition to both the more modern thermal vacuum stamping of polystyrene spoons, and and both of the classic methods for creating custom spoons.

Without what, it is impossible to manufacture dentures in the modern world? Yes, without high-quality impressions (functional and anatomical, which we will discuss later). To make a suitable design, an imprint of the tissues of the upcoming prosthetic bed is required. Mastering the techniques of obtaining high-quality impressions is a necessary stage in the career of every orthodontist. We will analyze the main classifications of these casts, methods of obtaining them, as well as the materials that are used to make them.

What is it?

What are anatomical and functional impressions in dental prosthetics (orthodontics)? This is the name of the reverse (or negative) reflection of the patient's teeth, various soft and hard materials of the oral cavity - the palate, alveolar ridge, transitional folds of the mucous membranes, etc. The impression is obtained using special materials.

The history of anatomical and functional impressions in dentistry dates back to 1756! Then the German doctor Pfaff was the first to make a similar impression, using simple wax as an impression material.

Why are impressions needed?

Why do you need an impression in orthodontics? It is on it that a positive model is made, which is an exact copy of the hard and soft tissues of the oral cavity.

Various impressions are used for diagnostic, therapeutic, educational, control and work purposes. Some models are valuable in that they help to clarify or refute the patient's diagnosis. Some are needed to make a prosthesis. And some of them allow us to evaluate the effectiveness of the orthopedic therapy performed (an impression before and after it).

The so-called functional functional impressions are needed for further production of prostheses by specialists. Auxiliary help to study the "relationship" of the antagonist dentition.

Classification according to Gavrilov

The fundamental gradation in orthodontics is the division into functional and anatomical impressions. What is the difference? The former are created taking into account the functional flexibility, mobility of the material that covers the prosthetic bed. The second, respectively, without such consideration.

Consider the classification of impressions:

• Functional. Most often they are removed from the toothless jaw. Less often - with the one where some of the teeth are preserved. The most important purpose is the basis for the manufacture of prostheses for edentulous patients. It is these prints that help to determine the optimal ratio of the tissues of the oral cavity and the edges of the prosthesis adjacent to them. This is important for better fixation of the device, as well as for the correct distribution of the so-called chewing pressure between the fundamental areas of the prosthetic bed. It is important to note that functional impressions are obtained by functional tests. The latter help to correctly form the edges of the prints in relation to the position of the movable tissues, which will later be located on the border with the prosthesis.
• Anatomical. Additionally, they are divided into main and auxiliary. The first type is removed from the jaw, on which the prosthesis will be installed in the future. The second - from the antagonist jaw (upper or lower), on which there will be no prosthesis. The anatomical type is widely used in orthodontics to represent the position of tissues (soft and hard) in the oral cavity. It is useful for making inlays, crowns, bridges and partially removable dentures.

An important difference between these varieties stands out from the characteristic. Obtaining functional impressions is important for the fabrication of a complete denture for an edentulous jaw. Anatomical is more likely to come in handy for partial dentures, bridge devices and other smaller-scale structures.

Another important difference between anatomical and functional imprints. For the former, standard impression trays are used. And for the second, these instruments are made individually for each patient. In order to better understand how impressions are obtained, functional and anatomical, let's figure out what is considered an impression tray.

What is an impression spoon?

The impression trays are made at the factory from plastic or Their shape and volume are determined by many factors at once:

• The patient's jaw.
• Type, width of the dentition.
• Defect location.
• Height of the crowns of the remaining teeth.
• The expressiveness of the jaw.

Even standard impression trays are varied in shape and size. First of all, they are divided into those intended for the upper and lower jaw. Removing functional impressions, as we said, is carried out with individual spoons.

Each of these tools has a body and handles. The body of the spoon will consist of an alveolar concavity, an outer rim, curvatures for the palate. For example, standard impression trays are available in ten sizes for the upper jaw and nine sizes for the lower.

Application of varieties of spoons

When working with elastic materials, special trays with holes are used for the impression. This is due to the fact that the base does not adhere well to the metal from which the standard spoon is created. Some specialists get out of this situation using their own resourcefulness: an adhesive plaster is glued to the inside of an ordinary metal tool. The elastic base adheres better to its fabric rough surface.

Also, cutting the handles of such spoons with special scissors for metal in case of their excessive length is considered a medical ingenuity and amateur performance. If the handle, on the contrary, is short, then it is lengthened with a wax plate. But in the collection of a qualified specialist usually there are standard spoons for any occasion, which saves him from such extreme measures.

So-called partial spoons are used much less frequently. They are used in relation to jaws with scattered single teeth. An impression is required for making crowns. Also, partial spoons are used for teeth that do not have antagonists in front of them.

Individual spoons

A functional impression with an individual tray is performed for edentulous jaws. Such instruments are distinguished by the height of the sides, the expressiveness of the niche for a slightly smaller size. It is explained by the fact that the imprint should provide the specialist with more accurate data on the prosthetic bed.

Why are individual spoons needed? As a rule, it is difficult to find two toothless jaws that are absolutely similar in appearance. For accurate fixation of the prosthesis, functional suction is required here, which is created by creating negative pressure... To do this, it is imperative that the surface of the prosthesis being manufactured is perfectly matched to the tissues of the prosthetic bed, which will be in contact with it. It is difficult to achieve this result without precise adjustment of the edges of the spoon to the borders of the valve region.

How is a custom spoon made? To begin with, a full anatomical impression of the jaw is taken using a standard instrument in an orthodontic clinic. Then, in the laboratory, an individual model is made from plastic on its basis.

Oksman classification of the impression base

We figured out the impression trays. The second important component is the materials for the functional impression. According to this classification, they can be divided into the following types:

• Crystallizing masses. This type includes "Dentol" (domestic zinc oxide paste), gypsum, eugenol.
• Thermoplastic materials. These are wax, stens, stomatopast, adhesives, Kerr and Weinstein masses.
• Elastic masses. Stomalgin and algelast are included in this category.
• Polymerizing masses. Silicone impression bases, AKT-100, styracryl.

Classification of the impression base according to Doinikov and Sinitsyn

Let us present another classification common in orthodontics, which separates the materials used for taking functional and anatomical impressions of the jaws.

At the beginning, two groups are distinguished. The first one is based on the physical state of the material:

• Elastic.
• Polymerizable.
• Thermoplastic.
• Solid crystalline.

The second gradation divides materials into categories by chemical nature:

Crystallizing materials

Let us describe in more detail the substances that are most often used in orthodontics for taking anatomical and functional impressions. It is important to highlight its other name - semi-aqueous sulfate salt. It is obtained from ordinary natural gypsum subjected to a special heat treatment. As a result of this process, the material is converted from dihydrous to semi-aqueous.

The alpha modification of medical plaster is considered the most suitable for dentistry. It is obtained when high blood pressure and temperature in the autoclave. The substance is distinguished by the best strength and density.

Elastic materials

The basic raw materials here are seaweed, from which alginic acid is obtained by technical means. The basis of the material is the sodium salt of this acid, which swells in water, forming a gel mass. To increase its elasticity and strength, gypsum, barium sulfate, white soot, etc. are additionally added to the impression-taking composition. Gypsum turns a soluble gel into an insoluble one. The rest of the components allow the gelation process to proceed more smoothly.

Requirements for functional impressions

The requirements for the resulting model are rooted in the requirements for the materials used to make the impression:

Making high-quality impressions is a prerequisite for a perfectly fitting denture. Therefore, considerable attention is paid to this area in orthodontics. Today there are special technologies for taking impressions, a wide range of materials and tools required for this work.

To obtain a functional impression in dentistry, an individual tray is used, which is made from an anatomical impression. The individual tray corresponds to the prosthetic bed as much as possible and allows functional tests, therefore, the impression reflects it more accurately. There are four main methods of making custom spoons, listed below in chronological order.

1. Manufacturing of an individual spoon from fast-hardening plastic;
2. Manufacturing of an individual spoon from a thermoplastic plastic plate by vacuum forming;
3. Making an individual spoon from a photopolymer composite plate;
4. 3D printing.

The oldest and most common method is to make a spoon from cold polymerized plastic (Protakril-M, etc.). To do this, a plaster model is cast from an ordinary plaster of paris (class II) from the anatomical impression. Trim the model with a trimmer. With a chemical pencil, draw the border of the future individual spoon. Usually, the border runs 1-2 mm before reaching the deepest part of the vestibule of the mouth, i.e. 1-2 mm shorter than the base edge removable denture... Also, the edge of the spoon does not reach the bridle and strands by 1-2 mm. This space is necessary for the correct design of the edges with thermoplastic or viscous silicone impression materials.

Making an individual spoon from fast-hardening plastic.

Next, the plastic is kneaded by cold polymerization according to the manufacturer's instructions (usually in a weight ratio of powder to monomer 2: 1). The easiest way to model a cold-curing plastic spoon is to use a special silicone mold with a base-shaped model several millimeters high. A thin plastic film (cling film, etc.) is spread on the bottom of the mold, the mixed plastic is poured into the mold, aligned in the mold and closed on top with a second layer of film. It is left for a few minutes for the plastic to ripen and 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. Then the plastic is adapted to the model through the film. The film is removed and the handle is modeled from the excess part of the material (plastic that has gone beyond the boundaries of the spoon). If it is necessary to model the support for the fingers on the spoon in the lateral sections, then this is also done from excess plastic.

Next, the dental technician waits for the plastic to harden. After hardening, remove the spoon from the plaster model, if necessary, separate the wax from the spoon. Shortens the spoon according to the drawn borders on the model. If necessary, perforations are made in the spoon for better adhesion to the impression material.

Figure: Quick-hardening plastic spoon modeling.
AND.Film on the form;
B.Filling the mold with plastic and overlaying a second film on top;
IN.Spoon modeling;
G.View of the finished spoon.

Benefits:

• Cheapness;
• Lack of gripping in the area of \u200b\u200bundercuts;
• No need for special equipment.

disadvantages

• Toxic as technician inhales monomer vapors;
• Limited simulation time;
• The need to isolate undercuts on the model;
• The inconvenience of modeling a handle.

All stages of making an individual spoon from chemically cured plastic are presented in the video.

Manufacturing of an individual spoon from a thermoplastic plastic plate by vacuum forming.

After completing the drawing of the borders, the undercuts are blocked using a special material resistant to high temperatures (Erkogum and others). Fit a handle. Next, the model is placed in the center of the perforated table of the vacuum forming apparatus. A special porous rubber plate (Erkopor, etc.) with a thickness of 3 mm is applied to the model. Install a thermoplastic polystyrene plate (Erkorit klar, etc.) in the holder and start the vacuum forming process. The plate heats up and after the transition to a plastic state it is lowered down, tightening the model, while at the edges with the table of the vacuum forming apparatus, a tight connection is formed. The vacuum pump between the plate and the table creates a vacuum due to which the plate adheres tightly to the model and to the table of the apparatus. A special aluminum spoon is heated with a burner and in the right place it is fused into the plate or a plastic handle is glued to the spoon with a special glue.

After cooling, the model with the plate is removed from the apparatus. Cut off the spoon along the borders, if necessary, make holes in the spoon.

All stages of making an individual spoon by vacuum forming are presented in the video.

Benefits:

• Ease of manufacture;
• No toxic materials.

disadvantages

• Special equipment required;
• Special materials required;
• Inconvenience of grinding a spoon (the material can melt and clog the cutter);
• There is no possibility of making finger supports in the side section of the spoon;
• It is necessary to isolate the undercuts on the model.

Making an individual spoon from a photopolymer composite plate;

After finishing drawing the borders, the undercuts are insulated with wax in order to be able to remove the finished individual spoon from the model. Heat the base wax plate and press it evenly on the model. Crop it along the previously drawn border. In the area of \u200b\u200bthe palate and alveolar processes in the lateral region, round or square holes (windows) are made in the wax to create restraints 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 mucous membrane, which will be filled with a corrective silicone mass. The area of \u200b\u200bthe windows is lubricated with insulating varnish (Izokol-69, Picasep, Vaseline, vegetable oil and etc.).

A special photopolymer plate (Individo Lux, Fastray LC, etc.), having the consistency of plasticine, is crimped on the model, cut along the borders.

Figure: Photopolymer plates for the manufacture of individual spoons.

From the cut parts of the photopolymer plate, the handle of the spoon and the finger supports in the lateral section are modeled. After completing the simulation, place the spoon in the light cure for a few minutes. After polymerization, remove the spoon from the model, remove the wax, make holes in the spoon if necessary, grind the edges of the spoon.

AND.Adaptation of the plate to a wax-insulated model;
B.Cutting platinum along the border;
IN.Handle modeling;
G.Cleansing the finished spoon from wax;
D.Drilling holes in the spoon;
E.View of the finished spoon.

Benefits:

• Ease of manufacture;
• High production speed;
• Convenience of modeling the handle and supports;
• Convenience of grinding the spoon (the material does not melt and does not clog the cutter);
• There is no time limit for simulation.

disadvantages

• Special equipment is needed, but it can be replaced with a regular halogen lamp;
• Comparatively higher manufacturing cost;
• The need to isolate undercuts on the model.

Detailed steps for making an individual spoon from a photopolymer plate are presented in the video

3D printing.

A digital model is obtained in the oral cavity using an intraoral 3D scanner, or a cast anatomical plaster model is scanned. With the help of a special program (CAD technology), an individual spoon is modeled. The simplicity of modeling lies in the fact that the program itself automatically blocks undercuts, leaves the necessary gap between the spoon and the model, draws the boundaries of the spoon. But at the same time, the dental technician still has the opportunity to correct any stage of modeling an individual spoon.

Rice... Simulation of an individual spoon on a computer.
AND.Blocking undercuts;
B.Drawing the border of the spoon;
IN.Digital model;
G.Digital ready-made model of an individual spoon

How the modeling of an individual spoon is carried out on a computer is shown in detail in the video.

After completing the simulation on the computer, the spoon is transferred to the printer for 3D printing. After printing, if necessary, the suprastructures are cut, and after that the spoon is completely ready.

Figure: 3D printed custom SLA spoon.

Several 3D printing methods are used to make a custom spoon.

1. MJM and the like;
2. SLA and the like;
3. FDM and the like;
4. SLS and the like.

Let's take a closer look at the SLA printing method. The digital model of an individual spoon is divided into layers. The platform is lowered into the tank filled with photopolymer plastic, not reaching the bottom by 20 microns or more. In the right places the layer is photopolymerized with a laser beam. The platform rises a few millimeters, and uncured photopolymer falls under the polymerized layer. The platform is lowered again so that there is a gap of 20 µm or more between the cured layer and the bottom. The layer is polymerized with a laser beam again in the required places according to the second layer of the digital model of an individual spoon. By repeating this procedure, all the layers of the spoon are printed in turn. After printing is complete, the spoon is removed from the platform and the supporting structure is separated from it.

Benefits:

• Ease of manufacture;
• Convenience of modeling;
• Lack of toxic materials;
• No need to sand the spoon;
• High accuracy;
• Sending a digital model from clinic to laboratory via the Internet.

disadvantages

• A computer with a special software and a 3D printer;
• Long printing times.

How SLA printing is carried out is shown in detail in the video.

findings

Thus, the most optimal method for making an individual spoon from photopolymer plates, since there is no need for expensive equipment such as vacuum forming or 3D printing, and the polymerizer can be replaced with a conventional dental photopolymer lamp or a halogen lamp or even sunlight in sunny weather. Fast manufacturing in contrast to 3D printing. There is no time limit for the modeling process, there is no toxicity due to the absence of volatile monomer, in contrast to the manufacture of a spoon from chemically cured plastic. The modeling process is much more convenient. The only drawback of modeling with photopolymer plates is the relatively high cost of manufacturing an individual spoon.

Using a plaster model, a spoon is made of wax, a small (up to 1 cm) wax handle is modeled in the area of \u200b\u200bthe front teeth, a model with a wax spoon is cast into a cuvette, the wax is melted, replaced with plastic, polymerized, processed, but not polished, the spoon.

You can make a spoon from self-hardening plastics (protacryl, carbodent, redont) by free molding and polymerization under pressure in water at room temperature. A plastic dough is prepared according to the previously described method, which is rolled out on a polyethylene plate with a glass rod to a thickness of 4 mm. From the resulting plate, a spatula is cut out a shape corresponding to the shape of the upper or lower toothless jaw. The resulting plate is placed on the model with the applied Isokola insulating layer. and molded.

The hardening of the plastic is accompanied by an exothermic reaction, which causes the plastic dough to drift slightly from the plaster model along the peripheral edge of the spoon. At this point, you need to re-compress the edges of the spoon. In order to avoid deformation of the spoon, polymerization is recommended to be carried out in water at room temperature under pressure.

An individual spoon can be obtained from a standard AKR-P plate, which is softened in hot water and squeezed according to the model. In case of premature hardening, the unformed section of the plate is softened again and re-compressed according to the model. The excess plate is cut off with scissors along the marked boundaries. From the remains

Figure: 181. Individual impression tray.

a - outer surface; b - inner surface; “- the moment of checking the boundaries of the spoon.

Rice. 182. Functional casts, edged with wax (solid black line).

a - blind man from the lower jaw; b - cast from the upper jaw.

the plates make a handle with a very hot spatula. An individual impression tray can be obtained from a plate of polystyrene or plexiglass with a thickness of up to 3 mm directly on a plaster model in a pneumatic press with a heater (PPS-1) and a dry-air polymerizer (PS-1).

Individual impression trays are fitted by the doctor in the patient's mouth, shortening the edges and forming them with a thermoplastic mass, using Herbst functional tests for this purpose.

After fitting the spoon, the doctor, depending on the flexibility and mobility of the mucous membrane of the prosthetic bed, takes a functional impression using elastic materials (thiodent, sielast), hardening (dentol, repin, gypsum) or thermoplastic masses (MCT-02, etc.).

After receiving an integral functional cast with plaster, it is edged. The edging is necessary to maintain the bulk of the prosthetic margin to ensure that the valve is closed during function. The edging is carried out as follows. With a chemical pencil, leaving 2-3 mm from the outer edge of the impression, mark a line along which a pre-prepared edging roller of wax 2-3 mm thick is attached with melted wax (Fig. 182).

Upon receipt of the model, the trace from the edging will maintain the outer boundaries of the neutral zone, necessary for the formation of the valve zone. The edging helps the dental technician to protect from violation of the border of the neutral zone when opening the plaster model, cast from a functional impression, which the doctor obtained using functional tests.