Prosthetics is considered a common dental procedure. It involves the manufacture of structures, tooth processing, impression taking, fixation of the prosthesis. The patient will need to go not only to the orthopedist. It is also necessary to visit a specialist to take dental impressions. This procedure is described in the article.
The concept
A cast of teeth is a display of teeth, soft tissues and bone structures of the oral cavity on a special material. An impression is a material that has hardened after being removed from the mouth. It includes the contours of the teeth, the display of mucous-alveolar cords and other structures: transverse palatine sutures on the upper jaw, frenum, lips, tongue.
Without a cast of teeth, it will not be possible to make gypsum models and an orthopedic construction. Impressions are performed not only by orthopedists, orthodontists also carry out this procedure. Using casts, diagnostic or working models are created to study the pathological shape of the bite, measure the size of teeth, and jaws.
What is the withdrawal for?
Dental casts are necessary for:
- Braces. These systems perform the correction of various tooth pathologies. Lingual braces are usually performed on the basis of individual casts.
- Trainers. Soft elastic tires eliminate abnormalities. Since the facial esthetics of closing teeth is different for everyone, a cast is made before installing the products.
- Records. Eliminate an imperfect bite in childhood will turn out records. So that the product is worn in one motion, it is made on the basis of an individual impression.
- Removable dentures. When there is no possibility of prosthetics with fixed elements, removable prostheses are created. They may be different, but they all perform on the basis of dental casts.
- Single crowns. If one or more teeth are lost, crowns are placed. To obtain a high-quality impression, 2 methods are used: polyester mass and open spoon.
- Bridge prostheses. Impressions are performed from the jaw several times. The first is for creating the framework of the prosthesis, the second is for the body.
- Individual abutments. Before implant implantation in the gum, a cast is taken. Based on the print, the type of abutment is selected.
More casts are needed for crown tabs, retention mouth guards, and eliners. Performing this procedure allows you to make dental appliances with high quality.
Kinds
Impressions of teeth are divided according to different criteria. They may be:
- anatomical and functional;
- full, partial;
- alginate, silicone, polyester (by material);
- one-stage, two-stage;
- single-phase, two-phase;
- compression, decompression.
With the help of anatomical impressions, the state of teeth, soft tissues, and bone structures is displayed during physiological rest. Such casts are performed more often, but they have their own testimonies.
Functional prints involve conducting Gerbst samples, which help to produce a print with shaped edges when retracting the cheeks, pulling the lips forward and opening the mouth wide. This is important, since taking these parameters into account will help to make a design that does not burden the patient's life. Such prints are usually performed for complete removable prosthetics.
Solid materials
For the manufacture of models, various materials are used. Teeth casts are often made of hard materials. The main one is crystalline gypsum. It is appreciated for its accessibility, low cost, and accurate display of tooth prints and soft tissues.
Now it is rarely used, since gypsum with crystallization and hardening is removed from the mouth in parts, and the doctor needs to compare them into an integral model. Also, gypsum should not be used to remove impressions from teeth characterized by strong mobility.
Elastic materials
You can make a cast of teeth from elastic materials. Alginate substances are actively used. The advantages include: accessibility, a good display of the structures of the oral cavity, a color change during the mixing of the material, which is evidence of its readiness for putting in a spoon.
Of the shortcomings emit a strong deformation of the mold. It is necessary to quickly cast plaster models. Alginates may not work. For some crowns and bridges, an accurate representation of the gingival portion of the teeth is required to obtain an accurate model. Such prints are used for stamped crowns, inlays, full removable dentures, arch prosthetics. A representative of dentists is the material "Stomalgin".
Silicone
2 types of silicones are used: C-silicones and A-silicones. These names are obtained due to the polyaddition reaction or polycondensation, which are the basis of hardening masses. They are the best materials for obtaining impressions, which provide an accurate display of the gingival area of the tooth and the ledge.
Before the use of A-silicones, the complete elimination of moisture is not required. The disadvantage is the cost: it is high.
C-silicones must be isolated from oral fluid. Such prints are used for solid structures, for example, Puffy Speadex. These materials include Dentol, a material with guaiacol, clove oil, and zinc oxide. It has good properties and a pleasant taste.
Polyester
They are expensive, but allow you to get an accurate display of the relief of the soft tissues of the oral cavity, teeth, bone formations. This helps to take a dental impression with maximum detail.
Thermoplastic
As the name implies, the state of these materials varies with temperature. During heating, the material softens, and during cooling, solidification occurs. The advantages of this type include:
- ease of use;
- good connection with an impression spoon;
- reusability.
But there are also disadvantages:
- the risk of the appearance of deformation of the mold when removing the mass;
- not quite high-quality display of the oral cavity.
This group includes the masses of Kerr 1, 2, 3:
- Used to relocate dentures from the toothless jaws. Even with this type of impressions for prosthetics are removed with full adentia.
- They are used in the manufacture of maxillofacial devices.
- Semi-crowns casts, tabs, some tires are taken.
Modeling
Include various materials. The main ones are: wax, stearin, paraffin, and combinations thereof. Of the advantages distinguish:
- convenience;
- universality;
- Accurate imprints of teeth and soft tissue.
A disadvantage is the high risk of deformation due to softening of the wax under the influence of temperature.
Requirements
For a dental impression for prosthetics to be of high quality, it must meet the following requirements:
- Accurate display of dentitions, transitional folds of the oral cavity, transverse palatal folds, frenum, buccal-alveolar cords.
- Exclusion of pores, deformations.
If on casts after removal from the teeth there are deformations, pores, inaccurate display, re-imprinting is required. Indeed, the accuracy of removal affects the ease of use and prevents personal injury from the product.
Preparatory work
Almost immediately after choosing a product, the doctor takes impressions. But before that, under local anesthesia, he performs the preparation of hard tissues of the teeth. Then, drying the oral cavity with cotton swabs is required. A special tool can be used - a gun.
Then the selection of a spoon is carried out, its fitting. When the size is determined, the material is kneaded. In the complete absence of teeth, a change is made in the dentition. If they are absent for a long time, bone tissue decreases, bone outgrowths occur - exostoses. Therefore, before taking the impression, surgical preparation of the oral cavity for prosthetics is required.
Withdrawal
How to make a mold of teeth? When the clinical situation is assessed, the material for the impression is selected, the teeth are treated, the impression material is kneaded by the doctor and introduced into the spoon. The mold is injected into the oral cavity. Spoons are:
- metallic and non-metallic;
- upper, lower;
- compression, decompression.
The size of the spoon is determined by the size, shape of the jaw, the width, duration of the dentition and the height of the crowns. Orthopedic surgeons have standard spoons, thanks to which you can determine the size.
But not in every case it is possible to use standard spoons, sometimes there is a need to create individual devices. The doctor can make a spoon himself. This work is done by a dental technician. Based on the clinical situation, type of design, the doctor selects the appropriate class of prints, their type. Then the specialist kneads the material and takes an impression. Then the mold is washed under running water and treated with a disinfectant solution. Then the gypsum is kneaded and the model is cast.
Cost
The price of a dental impression for braces can be different. This is determined by:
- individual features;
- material selection.
An important nuance is the accurate display of the gingival part. This will allow for high-quality prosthetics. Doctors often suggest using expensive materials.
The success of treatment depends on the qualifications of the specialist. A competent doctor determines the need for the use of materials and selects a suitable prosthesis. Correctly made dental casts will help to carry out high-quality treatment.