Basic classification of toothless jaws

The need for classifications of toothless jaws is determined solely by practical considerations. Their presence allows you to determine the treatment plan, facilitates the interaction of specialists and the formation of the patient's medical history.

When identifying signs of a particular type of jaw, the doctor forms a clear idea of ​​the typical difficulties that he may encounter in further work. Of course, none of the classifications of toothless jaws that exist today contain comprehensive characteristics. The fact is that between the extreme types there are also transitional forms.

In the article, we consider the main classifications of toothless jaws , proposed by different experts.

Shredder Separation

The classification of the toothless upper jaws is based on the degree of atrophy (decrease) of the alveolar processes (parts of the jaw that carry teeth). The scientist identified three types.

The first is characterized by pronounced areas of anatomical retention (the structure of the bed, ensuring retention of the prosthesis). In the classification of toothless jaws according to Schroeder, in particular, the first type of atrophy includes:

1. The presence of a high palatine arch.
2. Pronounced jaw tubercles and alveolar bone.
3. Highly located areas of fixation of the folds of the mucosa and muscle fibers.

These manifestations do not create obstacles for the prosthesis. Moreover, in the classification of toothless jaws according to Schroeder, this type is considered the most favorable for prosthetics.

With an average degree of atrophy of the appendix, they speak of the second type of jaw. The hillocks of the upper jaw are preserved, and the arch of the sky is clearly expressed. Transitional fold is slightly closer to the top of the appendix than in the first type. A sharp contraction of the facial muscles can lead to a violation of the fixation of the prosthesis.

For the third type of jaw, significant atrophy is characteristic. The sky is flat, and tubercles and alveolar processes are absent. The transitional fold is in the same plane with the hard sky.

Prosthetics of such a jaw is accompanied by significant difficulties. Fixation of the prosthesis is almost impossible.

Lower jaw

Its anatomical and physiological characteristics differ significantly from the characteristics of the upper jaw. According to experts, the conditions for the manufacture and subsequent use of removable dentures are less favorable.

In the classification of toothless lower jaws , 4 types are characterized. It was proposed by L. Keller.

In the first type of jaw, the alveolar processes are atrophied slightly and evenly. Due to the evenly rounded crest, the placement of the prosthesis is not accompanied by difficulties. Displacement of the product to the sides and forwards is practically excluded.

At the base of the alveolar processes are areas of attachment of folds of the mucosa and muscles.

This type, in accordance with Keller's classification according to the classes of toothless jaws , occurs with simultaneous extraction of teeth and slow atrophy of the alveolar part. It is considered the most convenient for prosthetics.

The second type in the classification of toothless jaws according to Keller is characterized by a pronounced, but at the same time uniform atrophy of the alveolar processes. This part rises above the bottom of the oral cavity. In the anterior section, the alveolar part looks like a narrow, in some cases, acute formation. It is unsuitable for staging a prosthesis.

The areas of muscle attachment almost coincide with the level of the apex of the alveolar part.

On this type of jaw, prosthetics are difficult, since there are no conditions for anatomical retention. In addition, due to the high location of the areas of muscle attachment and the absence of a transitional fold with a reduction in chewing muscles, the prosthesis shifts. Using the product is often accompanied by pain. In some cases, successful prosthetics can be achieved after smoothing the sharp edge of the maxillohyoid line.

The third type is characterized by severe atrophy of the alveolar processes of the lateral part with a relatively normal state of them in the anterior section. This situation occurs in the case of early extraction of chewing teeth.

The third type of jaw is considered relatively favorable for prosthetics. Between the jaw-hyoid and oblique lines in the lateral sections there are flat, almost concave surfaces. They are free of muscle attachment sites. Prevents the displacement of the prosthesis alveolar part of the anterior section.

The fourth type of jaw is characterized by pronounced atrophy of the anterior part of the alveolar processes with their relative safety in the lateral regions. Because of this, the prosthesis slides forward, losing support.

Division of jaws I. M. Oxman

This scientist characterized both the upper and lower jaws. A single classification of toothless jaws according to Oxman involves a division into 4 types.

Upper jaw:

1. The first type is established for jaws with a high alveolar process, high maxillary tubercles and the location of the sites of attachment of buccal cords, frenum and transitional fold, expressed palatal arch.
2. The second type is diagnosed with moderate atrophy of the maxillary tubercles and alveolar processes, less deep palate, lower attachment of the movable mucosa.
3. With the third type, there is a sharp and at the same time uniform atrophy, flattening of the arch. The mucous membrane is attached at the top of the appendix.
4. The fourth type is diagnosed with uneven atrophy. It combines the characteristics of all other species.

The lower jaw is also divided into 4 types. According to the classification of toothless jaws according to Oxman , they have the following features:

• Type 1 - a high alveolar process, a low location of the transitional fold and areas of fixation of the buccal folds and frenum.
• Type 2 - uniform, moderate atrophy.
• Type 3 - the alveolar process is weakly expressed or completely absent. At the same time, atrophy can spread to the body of the jaw.
• Type 4 - uneven atrophy. It occurs when teeth are removed at different times.

Alternative split

There is also a classification of toothless jaws according to Courland . He divided the jaws into types not only by the degree of decrease in bone tissue in the alveolar part, but also by changes in the topography of fixation of muscle tendons.

According to the classification of toothless jaws proposed by Courland, there are 5 types. The third type can be considered intermediate between the 2 and 3 types described by Keller.

It has already been said above that not a single classification makes it possible to foresee the whole variety of variants of atrophy. The relief and shape of the alveolar ridge is also important for the quality use of prostheses. The maximum stabilization effect can be achieved with uniform atrophy.

Classification of impressions of toothless jaws

It can be carried out according to two signs: the height of the edges and the degree of squeezing of the mucosa.

According to the first criterion, anatomical and functional prints are classified. A subtype of the latter are functionally absorbable prints.

Depending on the degree of squeezing of the mucosa, loading (compression) and unloading types of prints are distinguished. Let us consider briefly each of them.

Anatomical prints

They have high edges. When removing such prints, a standard spoon and gypsum in large quantities are used. As a result, soft mobile tissues are stretched, and the prosthesis overlaps them far beyond the neutral region.

Functional Impression

Its edges are lower than the anatomical. A functional impression is removed using a spoon and a small amount of gypsum. At the same time, soft mobile tissues practically do not stretch. The prosthesis ends on a neutral site or overlaps the mucosa by 1-2 mm.

Functionally suction print

It is also removed with an individual spoon. However, the boundaries of such a print should be slightly larger and overlap the neutral region by 1-2 mm. The oral edge of the upper part should be 1-2 mm behind line "A".

Relief print

With it, you can minimize pressure on the mucous membrane. Relief prints are removed using gypsum without pressure.

There are 2-3 holes on the palatine side of an individual spoon. When pressed, excess gypsum flows through them. This minimizes pressure on the sky.

Compression print

It is used for mucosal compliance. It is removed using thermoplastic, silicone and alginate materials. They are introduced into the mouth under pressure. In some cases, you can use gypsum. However, in this case, the pressure should be continuous. There should be no holes in the spoon.

Pros and cons of prints

Some experts oppose the use of relief prints. This position is based on the fact that all chewing pressure falls on the alveolar process. In this regard, his atrophy begins.

Dentures made on compression prints rest on the fabric of the buffer areas, like pillows. In this case, the alveolar process remains unloaded. When chewing under pressure, the vessels of the buffer section are emptied of blood. The prosthesis exerts pressure on both the buffer zones and the process. As a result, the latter does not atrophy.

Doinikov classification

It is based on the unevenness of atrophy. Doinikov identified 5 of its degrees:

• 1 - on the lower and upper jaws, the alveolar ridges are well defined; they are covered by a slightly supple mucosa. Its natural folds are somewhat removed from the top of the appendix and the alveolar part. The mucous evenly covers the sky. Jaws of this type are considered convenient for prosthetics, including when using products with a metal base.
• 2 - medium degree. The maxillary tubercles are moderately pronounced, the depth of the sky is average. The palatine torus (bone elevation, thickening of the palatine suture) is well defined.
• 3 - the alveolar part and the process are completely absent, the body of the jaw and maxillary tubercle are sharply reduced, the torus is wide, the sky is flat.
• 4 - alveolar ridge is expressed in the anterior section. Significant atrophy is noted in the lateral areas.
• 5 - in the lateral sections, the alveolar ridge is pronounced, significant atrophy is observed in the anterior section.

This classification is considered the most convenient in the practice of an orthopedic surgeon, since it covers the maximum number of cases, characterizes the picture of not only the degree, but also the localization of atrophy. Meanwhile, practitioners use all known classifications in their work. This allows you to accurately select the prosthetics tactics.

Mucous prosthetic bed

It is characterized by the degree of compliance, sensitivity and mobility. There are three types of mucous membranes:

1. Normal It is characterized by moderate compliance, good hydration. The mucosa has a pale pink color. It is considered the most favorable for the installation of the prosthesis.
2. Hypertrophied. When palpating, the mucous membrane is loose, with a high content of an intermediate substance. It has good hydration. With this type of mucosa, it is not difficult to create a valve, but the prosthesis will be movable due to the compliance of the membrane.
3. Atrophied. Such a mucosa is very dense, whitish in color. The shell is dry. It is considered the most unfavorable for the prosthesis. The mucous membrane covering the maxillary alveolar process, is connected to the periosteum motionless. Almost throughout its length, it consists of its own layer and squamous squamous epithelium. On the latter, in the region of the appendix, a stratum corneum is present.