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The sequence of clinical and laboratory stages of manufacturing a partial removable laminar denture. Methodology for assessing and analyzing occlusion

To obtain a plaster model, it is necessary to collect a cast, accurately place its parts in a spoon, and then glue them together and to the spoon with molten wax.

The collection of the cast begins no earlier than 30-40 minutes after removing it from the oral cavity, so that the moisture on the surface of the cast can evaporate.

Before placing parts of the cast in a tray, it is necessary to very carefully clean their surface adjacent to the tray, as well as the inner surface of the tray, from small particles of plaster that interfere with the accurate preparation of the cast.

The largest parts of the cast are placed first, and then the small ones. All parts of the cast must be accurately placed in the tray so that there is no gap anywhere between the tray and the outer surface of the cast. There should be no gaps on the inner surface of the cast, between its parts. The outer edges of the assembled impression are glued to the impression tray with hot wax. Pouring wax within the prosthetic field is not allowed; the slightest inaccuracy made during gluing the cast leads to distortion of the model.

The technique for obtaining a plaster model involves filling a cast or impression with liquid plaster, which is why this process is called model casting.

To make it easier to separate the cast from the model, it must be coated with an insulating substance. For these purposes, a number of substances are used that are applied to the surface of the impression. For this purpose, soap alcohol, kerosene with stearine and a number of other substances have been proposed. However, practice has shown that any insulating substance leaves a layer on the cast, resulting in an inaccurate model. Therefore, it is better to immerse the glued cast in cold water for 6-8 minutes; it fills all the pores, so that the model plaster does not adhere to the cast plaster.

For greater strength of the model, the plaster with which the cast is poured should have the consistency of sour cream.

The cast begins to be filled with small portions of plaster, and it is poured first onto the most convex part of the cast. The impression is shaken constantly to remove air bubbles. This is repeated until the entire cast is filled with plaster.

When the entire cast is filled, a mound is made from the remains of the plaster, which is placed on the cast; the latter is turned down and, together with the mound, pressed against a smooth object (glass, metal plate, etc.); The result is models with a wide base-stand, convenient for work. Thus, the model consists of two parts:

  • 1) the working part corresponding to the prosthetic field, i.e. the location of the future prosthesis,
  • 2) a stand that serves to stabilize the model.

Please note that the height of the stand should be at least 2-2.5 cm; This is of particular importance in the case of a deep sky, since the thinning of the model in this place can lead to the dream being pressed through during pressing under pressure from the press.

After the plaster has hardened, the edges of the model are trimmed with a spatula (Fig. 14).

Separating the cast from the plaster model. The cast is separated from the plaster model 8-10 minutes after casting, that is, when the plaster of the model begins to generate heat. This is the most favorable moment for separating parts of the cast from the model. The cast is removed very carefully to avoid damage to the model. First of all, you should free the teeth, guided by the dental formula, which indicates where and which teeth are located. To separate, use a dental spatula, inserting it shallowly along the fracture line of the cast, and using a lever-like movement, separate parts of the cast from the model. When all the teeth are freed, they tap the cast with a horn or metal hammer until a specific dull sound of emptiness appears, meaning that a gap has formed between the cast and the model; After this, the model is completely separated from the cast. If, when separating the cast from the model, a tooth breaks off, which has retained the clear contours of the fracture line, you can glue it to the model using a special liquid glue (a solution of celluloid in acetone). Gluing with cement is not recommended due to the fact that it prevents the exact fit of the tooth to the model.

In case of more serious damage to the model, for example, separation of part of the alveolar process, fracture of the model, scratches in the area of ​​the prosthetic field, etc., the impression should be retaken.

Separation of impression material from the model. When casting a model from an impression, no insulating substance is required so that the impression can be easily separated from the plaster model. After the plaster has hardened, the impression with the model is immersed in hot water for several minutes; The impression mass softens and is easily separated from the model.

Introduction

Bite registration is a double-sided impression of the occlusal surfaces of the antagonist teeth of the upper and lower jaws. From the patient's mouth, this information is directly transferred to the models in the articulator. This technique makes it possible to relatively easily create full-fledged restorations in the future and establish correct functional occlusal relationships at the laboratory stage of manufacturing orthopedic structures.

Material

O-Bite is an automatically mixed bite registration material based on A-silicones with high final hardness and optimal fracture strength.
The material is produced by DMG (Germany) in 50 ml cartridges.
Time characteristics: working time - 30 s, with polymerization time - 90 s, after the start of mixing.

Clinical case No. 1

When creating a combined implant-supported maxillary prosthesis, O-Bite was used during the initial bite registration process, and subsequently to control occlusion on wax models.

Stages of work

In Fig. 1.1 demonstrates the moment of applying the material to the dentition. The intraoral nozzle is not used to control the stability of the output of an increased portion of the material. Thus, the mass is introduced quickly and without much effort. A quick application procedure allows the patient to reduce the time during which he holds his mouth open, and thereby avoid possible errors due to muscle strain.

First of all, the material should be applied to the prepared areas. In this case, the optimal thickness of the material layer should be approximately 5 mm.

Consistent performance allows O-bite to cover extended occlusal surfaces without bleeding.

In the process of obtaining bite registration, no additional effort is required by the patient (Fig. 1.2). Failures at this stage have not occurred since O-bite made it possible to obtain impressions without resistance to teeth closure. The short polymerization time makes this part of the work more comfortable for the patient and the doctor.

Removing the finished registry from the oral cavity does not create problems at all. In the case of complex undercuts, material should be applied sparingly to prevent fracture during removal due to the high final hardness of the material (Fig. 1.3).

In the technical laboratory, O-bite was processed with various tools. Attempts to adjust the impression using a surgical scalpel proved difficult due to the rapid hardening of the material. The polymerized material was treated more successfully with carbide boron. The instructions for use recommend using a scalpel if it is necessary to trim the resulting impressions immediately after removal from the oral cavity.

Clinical case No. 2

In the second case, a single crown on the upper jaw had to be manufactured and fixed. The purpose of the observation was to assess the accuracy of occlusion reproduction in the articulator with and without O-Bite.

Stages of work

First, the models were placed in the articulator according to the previously obtained bite registration impression using O-Bite (Figs. 2.1 and 2.2).

After making the metal crown, the models were removed from the articulator and reinstalled, but without the bite register. This is only possible if the dentition is sufficiently complete, since occlusion is created by contacts of specific antagonist teeth (Fig. 2.3).

After placing the crown on the prepared plaster die (Fig. 2.4), the contact points were checked using colored articulation paper. Because these new contacts matched the original contacts exactly, O-Bite demonstrated very high accuracy (Figure 2.5).

Conclusion

In the oral cavity, the orange color of O-Bite is clearly visible for precise application and removal of excess material. The material also contrasts against the white, blue or brown background of the plaster models.

Minimal resistance to teeth closure, short residence time in the oral cavity and orange aroma are positively perceived by both the patient and the specialist. O-Bite provides accurate recording of habitual occlusion.

With a hardness of 93 Shore A, O-Bite is one of the toughest materials ever developed. This is especially important for matching patterns in the articulator. The use of softer materials can lead to silicone compliance and distortion of the occlusion height of the restorations, the correction of which in the future will result in a complex and time-consuming procedure.

The resistance of the material to fracture in the application technique allows you to avoid mechanical damage to the impression when removing it from the oral cavity, cutting, transporting and working with models.

*O-Bite scores 4.5 out of 5 in the latest Dental Advisor ratings. During the research, it was emphasized that the material received high marks for all tested indicators. However, 90% of researchers rated it as the same or better material than what they are currently using: No other bite registration material has achieved such ratings.

1589 21 ARTICLES

Diagnostic plaster casts of the jaws are made to create a replica of the patient's jaw. They are often also used to clarify the diagnosis. Using them, it is possible to obtain data on the peculiarities of the location of teeth, which is necessary for obtaining comfortable orthodontic structures and removable dentures. How are diagnostic jaw models made?

Making a plaster model of the jaw is an important stage in diagnostics and prosthetics. First, the doctor takes impressions using modern methods and materials. Later, with the help of plaster, it is possible to recreate plaster models of the jaws, which should closely replicate the main features of the patient’s real tissues.

After this, both plaster jaws are placed in an articulator, which simulates the movement of the jaws. You can easily buy a plaster model of the jaw at dental clinics. It will be possible to contact specialists if any diseases arise or the need to resort to prosthetics. Diagnostic jaw models must be of high quality. They necessarily provide information about the alveolar processes, tubercles, palate, frenulum and other soft tissue formations of the oral cavity. With the help of a high-quality plaster model of the jaws, you can clarify many controversial situations that arise during examinations and dental treatment.

Dental laboratory

    Own laboratory

    The FDC clinic has its own dental laboratory, equipped with the latest technology, so even the most labor-intensive orthopedic work is performed in the shortest possible time.

    Laboratory in France

    If necessary, exclusive work can also be performed in the most prestigious dental laboratory in France, Bourbon Atelierd’ Art Dentaire (Nice)

Enjoy European quality and style,
without leaving Moscow

The convenient location of the French dentistry and the availability of guarded free parking make visiting the Clinic as simple and convenient as possible in a big city.

Location within walking distance
from Moscow City

Near the metro station Ulitsa 1905 Goda

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Plastering models into an occluder.

Formed competencies:

(PC-5 (1.5));

Purpose of the lesson: study the types, structure and characteristics of occluders, the technique of plastering models of jaws into an occluder, study the nature of the closure of jaws in an occluder.

Total lesson time: 200 minutes.

Lesson equipment: Study room, visual aids, computer class, computers, TV, tables, slides, computer programs, multimedia projector, video on the topic of the lesson.

Lesson plan:

№ Stage name Description of the stage Pedagogical goal of the stage Stage time
1. Organizational stage. Check the students present, their appearance, discuss the lesson plan.
2. Test questions on the topic: 1. Occluders, their characteristics. 2. Comparison of plaster models according to the bite, gluing (fixation). 3. Plastering the model of the lower jaw into the occluder. 4. Plastering models of the upper jaw into the occluder 5. Studying the nature of the closure of the jaws (plaster models with teeth) in the occluder. Assessment of the state of occlusion. Discuss questions that students had while preparing for the lesson. Control of background knowledge on issues.
3. Training stage. Pedagogical story, demonstration, presentation of an algorithm for solving problems, instructions for completing tasks. To teach students the technique of plastering jaw models into an occluder, as well as assessing the condition of the bite.
4. Independent work Development of methods for comparing plaster models by bite, gluing, plastering jaw models into an occluder. Achieving the set goal of the lesson: study the types, structure and characteristics of occluders, the technique of plastering models of jaws into an occluder; study the nature of the closure of the jaws in the occluder. 120 min.
5. Control of the final level of knowledge acquisition. Tests, tasks, oral examination, test Using an oral survey, determine the degree to which the goal has been achieved.
6. The final stage. Answers to students’ questions, assessment of the group’s work, assignment of assignments, notification of the topic of the next lesson, tasks for self-study for students The teacher summarizes the content of the lesson


Lesson No. 6

3rd semester

PROPAEDEUTICS

Structure of the orthopedic department,

Orthopedic office.

Equipment and tools

Used in clinical settings.

Formed competencies:

PC-1, PC-2, PC-5(1,5), PC-6(2), PC-7(1), PC-9(1)



the ability and willingness to implement the ethical and deontological aspects of medical practice in communication with colleagues, nurses and junior staff, adults and adolescents, their parents and relatives (PC-1);

the ability and willingness to identify the natural scientific essence of problems arising in the course of professional activity, to use the appropriate physical, chemical and mathematical apparatus to solve them (PC-2);

ability and willingness to conduct and interpret interviews and physical examinations, clinical examination, results of modern laboratory and instrumental studies, morphological analysis of biopsy, surgical and sectional material, write a medical record for an outpatient and inpatient patient(PC-5 (1.5));

the ability and willingness to conduct a pathophysiological analysis of clinical syndromes, to substantiate pathogenetically justified methods (principles) of diagnosis, treatment, rehabilitation and prevention among adults and adolescents, taking into account their age and sex groups (PC-6 (2));

ability and willingness to apply aseptic and antiseptic methods, use medical instruments, carry out sanitary treatment of medical and diagnostic premises of medical organizations, master patient care techniques (PC-7 (1));

ability and readiness to work with medical and technical equipment used in working with patients, own computer equipment, obtain information from various sources, work with information in global computer networks; apply the capabilities of modern information technologies to solve professional problems (PC-9 (1));

Purpose of the lesson: study the structure of the orthopedic department and dental laboratory, know the basic tools of an orthopedic doctor. Study the main components of dental units, drills and handpieces. Know the classification and main characteristics of impression trays.

Total lesson time: 150 minutes.

Lesson equipment: Study room, treatment room, functional diagnostics room, computer class, computers, TV, tables, slides, computer programs.

Lesson plan:

№ Stage name Description of the stage Pedagogical goal of the stage Stage time
1. Organizational stage. Checking those present, reporting the topic of the lesson. Check the students present, their appearance, discuss the lesson plan.
2. Control of the initial level of knowledge. Security questions

Available on the topic: “goals and features of plastering orthopedic models in an occluder” with comments from dentists. You can ask all questions after reading the article.

  • Goals and features of plastering orthopedic models in an occluder

    In orthopedic dentistry, an important laboratory step is checking the manufactured structure. It is very important to evaluate its closure and the possibility of performing all types of occlusal movements. For this purpose, a dental occluder is used.

    This is a special device used in the process of creating orthopedic structures. Plaster models of the jaws are placed in it and a series of chewing movements are reproduced.

    The device includes 2 arcs: upper and lower. They are connected to each other by a transverse rod. If necessary, it can be removed.

    The finished models are plastered into the occluder. The upper model, accordingly, is fixed to the upper arch, and the lower one – to the lower one.

    The use of this device is indicated in the manufacture of all types of orthopedic structures. It reproduces jaw movements only in the vertical plane. Using this device, the central relationship of the jaws and the height of the bite are determined.

    All devices differ in size. They may be:

    The main classification is based on design features. There are occluders:

    • wire;
    • cast;
    • Vasiliev's universal device.

    A conventional hinge-type wire occluder consists of 2 arcs. One of them, most often the bottom one, bends at an angle of 100-110

    degrees.

    Between the arcs there is a hinge-type connection. To record the distance between the alveolar processes in the position of central occlusion, a screw or rod having a vertical direction is used. When using the device, it is important not to forget about this feature. Smooth and soft closure of the models is recommended so as not to affect the predetermined bite height. Rotating the rod allows you to change it.

    Sometimes the rod is not used. This occurs in situations where the patient has retained antagonist teeth. They are able to maintain the required bite height, which does not need to be determined again.

    Cast occluders are distinguished by the fact that their arcs are not made of wire, but are completely cast from metal.

    Separately, it is worth highlighting the universal occluder, which was modified by Vasiliev. Just like a regular hinged one, it includes an upper and lower arc. In this case, they are made not of wire, but of metal plates. Oval-shaped rings with holes for pins are soldered to them. They are responsible for fixing the plastered models.

    At the rear of the lower arc there are racks with holes for the rod. It is he who connects the 2 arcs to each other.

    There are recesses for the pin on the lower arc. You can find them on the front. The pin is responsible for maintaining the height in the position of central occlusion.

    The top bow has loops for the hinge rod. In its front part there is a hinge, with the help of which a pin is attached, which is inserted into a recess on the lower arc. The hinged connection of the arc and the pin allows it to be moved forward if necessary.

    • installation of models into the device using plaster;
    • transfer of data on the height of the bite and the position of the jaws in the position of central occlusion;
    • checking vertical movements, if any violations occur, they are corrected.

    Of course, the occluder is much easier to use than the articulator. However, its main disadvantage is the ability to reproduce only vertical movements. In turn, the articulator is capable of simulating movements in all directions.

    This is of greatest importance when providing prosthetics to patients with complete loss of teeth. The inability to assess horizontal movements does not allow testing of dentures in all phases of movement of the lower jaw relative to the upper jaw.

    The doctor has an additional burden of checking the prosthesis during delivery. It is necessary to re-check the closure and grind down the cusps and cutting edges of artificial teeth that interfere with the normal movements of the jaws.

    The articulator allows you to more fully assess the quality of the prosthesis even before the final processing of the structure. The technician has the opportunity to see defects in the closure from all sides, which is much more difficult to do in the oral cavity.

    Almost all doctors and dental technicians have already abandoned the use of an occluder. It is being replaced by modern models of articulators, which allow the creation of higher quality prostheses.

    Almost all designs must be checked at intermediate stages. This cannot be done without a full and comprehensive assessment. Its main stage is the precise determination of all occlusal relationships of the jaws.

    This laboratory stage is performed by all dental technicians. After the clinical stage of determining central occlusion. Models with occlusal ridges, fastened together, are delivered to the dental technician. After this, the models need to be fixed in the occluder in the position of central occlusion.

    · Place a pile of plaster on the table

    · We immerse the plaster into the lower frame of the occluder

    · We install phantoms on plaster in the position of central occlusion