Home Stomatitis Types of toothless jaws according to Keller. Kurlyandsky, Schroeder, Oksman, Keller, Doinikov - their classification of toothless jaws

Stomatitis

Types of toothless jaws according to Keller. Kurlyandsky, Schroeder, Oksman, Keller, Doinikov - their classification of toothless jaws

Causes, causing complete loss of teeth are different. Most common reasons are caries and its complications, periodontal diseases, trauma and other diseases. Primary (congenital) adentia is very rare. Complete absence of teeth can also occur with malformations of the dentofacial system. Adentia at the age of 40-49 years is observed in 1% of cases, at the age of 50-59 years - 5.5% of cases and in people over 60 years old - in 25% of cases.

With complete loss of teeth, due to the lack of pressure on the underlying tissues, functional disorders and atrophy of the facial skeleton and the soft tissues covering it rapidly increases. Prosthetics for toothless jaws is a method of restorative treatment, leading to a delay in the development of further atrophy.

With complete loss of teeth, the body and branches of the jaws become thinner, and the angle of the lower jaw becomes more obtuse, the tip of the nose drops, the nasolabial folds are sharply expressed, the corners of the mouth and even the outer edge of the eyelid droop. The lower third of the face decreases in size. Muscle flabbiness appears, the face takes on an senile expression.

In connection with the patterns of atrophy bone tissue to a greater extent from the vestibular surface on the upper and from the lingual surface - on the lower jaw the so-called senile progeny. The mechanism of its formation lies in the features relative position teeth of the upper and lower jaws in an orthognathic bite. If you draw a conditional line through the necks of the teeth of the upper jaw, then the formed alveolar arch will be smaller than the arc drawn along the cutting edges and occlusal surfaces (dental arch). On the lower jaw this relationship is reversed. Thus, with an orthognathic bite with all teeth present, the upper jaw narrows upward, while the lower jaw, on the contrary, becomes wider downward. After complete loss of teeth, this difference immediately begins to affect itself, creating a progenic jaw relationship. Senile progeny is characterized by a change in the relationship of the jaws in the transversal direction. Lower jaw it becomes, as it were, wider. All this complicates the placement of teeth in the prosthesis, negatively affects its fixation and, ultimately, affects its chewing efficiency.

With complete loss of teeth, the function changes masticatory muscles. As a result of a decrease in load, the muscles decrease in volume, become flabby and atrophy. Changes occur in the temporomandibular joint. The glenoid fossa becomes flatter, the head moves posteriorly and upward.

Influence of the etiological factor that caused the loss of teeth, the age of the patient, the duration of the loss various groups teeth leads to a combination of various changes, as a result of which the landmarks that determine the height and shape of the lower third of the face are lost. Prosthetics in the absence of teeth is one of the most difficult problems in orthopedic dentistry.

There are a number of features in the examination of patients with complete loss of teeth. Among subjective complaints that patients present, aesthetic dissatisfaction - sunken mouth, senile appearance, seizures, dysfunction of chewing and speech formation, complaints of pain, clicking and crunching in the TMJ, tinnitus, paresthesia of the oral cavity; People who apply again have complaints about poor fixation of prostheses.

When starting to provide prosthetics for patients with complete absence of teeth, the doctor sets himself 3 main tasks :

1) fixation of dentures on toothless jaws;

2) determining the necessary, strictly individual size and shape of prostheses so that they best restore the appearance of the face;

3) designing the dentition in dentures in such a way that they function synchronously with other organs of the masticatory apparatus involved in the act of chewing, speech formation and breathing.

To solve these problems, it is necessary to have a good knowledge of the topographic structure of toothless jaws.

For fixation of the prosthesis on a toothless jaw great importance has the height of the alveolar process, its shape, relief, the steepness of the vestibular slope, the severity of the alveolar tubercles of the upper jaw, the depth of the hard palate, the presence of a torus, the severity of the mylohyoid line, the hyoid torus. The less atrophied the alveolar process, the wider it is, the larger the area of the prosthetic field and the better its supporting properties.

The alveolar ridge may be : well expressed, moderately expressed, unexpressed and sharply atrophied; There are semi-oval, rectangular, pointed, truncated cone shapes of the alveolar process. The most favorable shapes for prosthetics are semi-oval and truncated cone, since chewing pressure is perceived on the limited surface of the apex of the alveolar process and is transmitted to its wider base. The least favorable in this sense is the triangular-pointed form, in which the mucous membrane covering the alveolar process is often injured and the fixation of the prosthesis worsens. Shape of the vestibular clivus the alveolar process can also be different: sloping, vertical and with canopies . The atrophied alveolar process in the upper jaw, the absence of alveolar cusps, a flat palate, and a pronounced torus constitute unfavorable conditions for prosthetics in the upper jaw. In the lower jaw, sharp atrophy of the alveolar process is combined with the sharpness of the mylohyoid line and the severity of the hyoid torus; this also worsens the conditions for prosthetics.

There are several classifications of toothless jaws: according to the degree of atrophy of the alveolar processes, alveolar tuberosities, the depth of the palate and the height of the transitional fold.

Shredder (1927) identified 3 types of upper jaw:

1 type- well-defined alveolar processes and tubercles, deep palate, high transitional fold;

Type 2– average atrophy of the alveolar process, moderately pronounced alveolar tubercles, average depth of the palatine vault and vestibule of the oral cavity;

Type 3– significant atrophy of the alveolar processes and tubercles, flat palatine vault and low location of the transitional fold.

Keller (1929) defines 4 types of lower jaw:

1 type– alveolar processes are atrophied slightly and evenly;

Type 2– the alveolar processes are atrophied evenly, the places of muscle attachment are located almost at the level of the alveolar ridge;

Type 3– pronounced atrophy of the alveolar processes in the lateral sections with relative preservation in the anterior section;

4 type- pronounced atrophy of the alveolar process in the anterior section.

There are also classifications by Kurlyandsky (3 types - for the upper jaw and 5 - for the lower jaw) and Oksman (4 types in a single classification for both jaws).

In addition to bone formations that influence the result of prosthetics, there are a number of landmarks in the oral cavity created by formations from the mucous membrane. On the upper and lower jaws, in the vestibule of the oral cavity, there are frenulums of the upper and lower lips and buccal cords. In the oral cavity itself there is a frenulum of the tongue. The frenulum of the lips and tongue can be attached to the base of the alveolar process, to the middle of its vestibular slope, closer to the apex and at the top of the alveolar process. On the upper jaw, the pterygomaxillary fold is defined when widely open mouth, and its location is taken into account in such a way that it does not overlap with the prosthesis. At the border of the soft and hard palate, on both sides of the sagittal suture, there are blind holes that are important for determining the border of the prosthesis. In the anterior part of the hard palate there is an incisive papilla - the exit point neurovascular bundle, a sensitive area of the mucous membrane of the palate, which painfully perceives a removable denture.

In the lower jaw, the retromolar, retroalveolar zones and sublingual space are important for prosthetics. In the retromolar region there is the mandibular tubercle; if it is represented by a stationary mucosa, it should be completely covered by the base of the future prosthesis; if it is mobile, then the prosthesis should cover only its front part. Of great importance for fixing the lower prosthesis is advancement into the retroalveolar region, where there is an area of muscle-free tissue. A reliable fixation area is the sublingual space, enclosed between the sublingual ridge and the inner surface of the lower jaw from the first incisor to the first molar.

Mucous membrane The oral cavity is divided into mobile and fixed (alveolar processes, hard and palate). The mobility of the mucous membrane depends on its connection with the muscles. In those places where the submucosal layer is developed above the muscle, there is adipose tissue and glands are located, the mucous membrane is inactive, but is highly pliable when pressed.

The least mobility and good pliability of the mucous membrane differs in the places of its transition from the jaw to the lips, cheeks, floor of the mouth and soft palate - in the area of the transitional fold, which on the vestibular side is a dome, a vault in the vestibule of the mouth, a bend of the mucous membrane.

Mucous membrane , covering the upper jaw, has different degree of compliance , the limits of fluctuations of which are 0.2-0.4 mm, derived by Spreng, allowed Lund to identify 4 zones :

1) – area of the sagittal palatal suture (median fibrous zone, practically not pliable);

2) - alveolar process and the adjacent zone (peripheral fibrous zone - has a mucous membrane, almost devoid of a submucosal layer, i.e. minimally pliable)

3) – the anterior part of the hard palate (covered with mucous membrane, having a submucosal layer of 1-2 mm, characterized by average pliability);

4) - the posterior third of the hard palate, has a submucosal layer rich in glandular tissue - the mucous membrane of this zone springs well under pressure and has the greatest degree of compliance).

Knowledge of compliance zones is of particular importance for prosthetics: in areas of inflexible mucosa, the base of the prosthesis should not fit tightly, but a well-compliant one should sink, forming a valve.

Gavrilov explains the pliability of the mucosa by the presence of buffer zones (he connects pliability with the severity of the vascular network of the submucosal layer). Areas of the mucosa with large vascular fields are called buffer zones and have spring properties.

Characterizing the state of the mucous membrane of the prosthetic field, Suppli identified 4 classes:

1) dense, with a well-defined submucosal layer;

2) dense but thinned mucosa, with an atrophied submucosal layer;

3) loosened mucous membrane;

4) “dangling comb”.

It should be remembered that removable dentures transmit vertical chewing load to the underlying tissues through the mucous membrane, which is poorly adapted to perceive chewing pressure. This must be taken into account when designing and manufacturing prostheses, since the use of removable dentures will lead to constant exposure, compression of a large number of nerve endings by the prosthesis, which will be subjectively expressed painful sensations. This is especially pronounced when squeezing the exit site of the incisive papilla and blind foramina.

Control questions on the topic of the lesson:

1. Changes in the facial skeleton and jaw bones with complete absence of teeth.

2. The degree of atrophy of the bone tissue of the alveolar processes of the upper and lower jaws.

3. Classification of toothless jaws:

A) according to Keller, Schroeder

B) according to Kurlyandsky, Oksman.

4. Classification of types of mucous membrane of the prosthetic bed (according to Supple).

5. Zones of compliance (according to Lund).

6. Pain sensitivity of the mucous membrane.

7. Classification of the condition of the mucous membrane according to Supple.

Lesson #2

Subject:“Clinical and laboratory stages of manufacturing complete removable plate prostheses. Functional impressions; individual spoons, methods of making them”

Purpose of the lesson : To familiarize students with the clinical and laboratory stages of manufacturing complete removable dentures; determine the purpose of an individual tray in the manufacture of complete removable dentures, study methods for making individual trays, give an idea of Herbst’s functional tests when fitting individual trays; study methods for obtaining functional impressions (unloading, compression, differentiated)

Test questions for verification background knowledge :

1. Anatomical formations important for prosthetics.

2. Characteristics of the anatomical impression, standard anatomical trays.

3. Clinical and laboratory stages of manufacturing a partial removable laminar denture.

4. Definition of the concept of “imprint”, classification of impressions (negative casts).

Manufacturing removable lamellar dentures for edentulous jaws is a strict alternating clinical and laboratory appointments.

Clinical events	Laboratory activities
1. Examination of the oral cavity. Obtaining anatomical impressions.	1. Making individual spoons.
2.a) fitting individual spoons. b) obtaining functional impressions.	2.a) making working models b) obtaining wax bases with occlusal ridges.
3.a) determination of the central relationship of the jaws. b) selection of artificial teeth by color and shape.	3.a) plastering the models into the occluder b) placing artificial teeth c) preliminary modeling of wax bases.
4. Checking the design of the prostheses.	4.a) final modeling of wax bases b) replacement of wax with plastic c) processing, grinding, polishing.
5. Application of dentures to the jaws.
6. Correction of prostheses.

The structural features of the oral mucosa and the submucosal layer of the prosthetic bed in each patient are taken into account when choosing an impression material and the impression-taking technique, which should determine a differentiated distribution of the underlying tissues into separate areas.

A study of the prosthetic bed and surrounding tissues before prosthetics and their correct assessment also make it possible to choose a technique for taking an impression, outline a plan for orthopedic treatment and determine its prognosis in each case.

When taking impressions of an edentulous jaw, the following factors must be taken into account:

1) the general contour (or relief) of the prosthetic bed;

2) the degree of compliance and mobility of the mucous membrane in various areas of the prosthetic bed;

3) the shape of the impression tray, the length of its edges;

4) properties of the impression material, and, above all, its fluidity in different forms of hardening;

5) the force of pressure exerted on the tissue of the prosthetic bed by the impression material when taking impressions;

6) method of designing the edges of the prosthesis;

7) technique for obtaining an impression.

When taking impressions with modern materials, rigid individual trays are usually used. You can selectively increase or decrease the pressure that occurs when taking an impression, influence the nature of its distribution, and therefore display the mucous membrane of the prosthetic bed differently on the impression.

Functional impression called an impression that reflects the state of the tissues of the prosthetic bed during function. Functional impressions can be: compression obtained by finger pressure or bite pressure, decompression (unloading) , obtained without pressure on the tissue of the prosthetic bed; differentiated , providing selective load on individual areas of the prosthetic field depending on their functional endurance.

A large number of masses have been proposed for taking functional impressions. Due to the wide variety of impression materials with different physical and chemical properties, it is advisable to group them by physical signs V 4 groups:

Thermoplastic (wax, adhesal, Weinstein mass, gutta-percha)

Elastic (stomalgin, elastic, sielast, algelast)

Crystallizing (gypsum, repin, dentol)

Polymerizing (self-hardening plastics AKR-100ST, PM-01, as well as all base plastics)

The impression material must have the following properties:

1) have high plasticity;

2) easy to enter and remove from the oral cavity;

3) have a constant volume when receiving impressions and casting models;

4) harden or structure relatively quickly at oral temperature;

5) accurately display the macro- and microrelief of the impression surfaces;

6) don't have unpleasant odor and taste and not provide harmful effects on the oral mucosa;

7) do not enter into a chemical reaction with the model material.

The strength of impression materials when subjected to tensile strength is also a significant indicator that determines their quality. When removing impressions from the mouth, conditions are often created that can cause the edge or other areas of the impression to separate from the total mass.

All impression materials have the ability to change their structure. From a semi-liquid or plastic state they pass into a solid or elastic state. The timing of these transitions is also an important indicator.

The loss of all elements of the dentition on the jaw is a big blow to the patient, and above all to his psyche and social status.

Along with the loss of teeth, confidence in one's attractiveness and the ability to perform normal daily tasks such as eating, speaking and facial expressions disappear.

We will talk about the features of a jaw devoid of teeth and its prosthetics later in the article.

Characteristics of the pathology

Normally, teeth are fixed in jaw bone using the alveolar processes or alveolar ridge.

Immediately after the removal of dental units, these elements of the jaws are expressed quite clearly, however, over time, changes in the alveolar processes occur; they are smoothed out due to the process of atrophy, since they normally experience a functional load, which disappears with the loss of bone organs.

Classifications of toothless jaws are, first of all, intended to organize the severity of atrophic processes, since they play an important role in the success of prosthetics.

Eg, Shredder, in addition to the main feature - the degree of alveolar atrophy, considers the severity of tuberosity on the upper jaw bone, the palatal area and the location of the valve fragment. However, he distinguishes only three types, which many authors considered insufficient.

Keller in his classification The defining features include the localization of pronounced alveolar processes and the location of other parts of the jaw relative to the topography of the teeth.

In Kurlyandsky's classification many signs are taken into account at once. Taking the experience of his predecessors as a basis, he considered the expression of the maxillary tuberosities and the shape of the palate to be an important sign, but in addition to this, he paid attention to the size of the bone body and the severity of the torus.

Oksman however, he generalized the knowledge and created a classification where there are types that are intermediate in severity.

Thus, each of the researchers has developed their own attitude towards the need to take into account various factors in the diagnosis of atrophic changes in the jaw.

Commonly accepted survey options

There are no uniform criteria for classification, because There are various schools of dentistry around the world.

In addition, tooth loss as a result of various etiological factors requires attention to various signs, and between any of the listed classes there are always transitional types.

According to Schroeder

The classification of this scientist describes the classes of the upper jaws, taking the degree of alveolar atrophy as the main feature (as in subsequent classifications).

First- the most advantageous modification for attaching the prosthesis– a fairly high arch of the palate, fairly pronounced alveolar tubercles and tubercles, the mobile mucous membrane is fixed high.
Second- Finepronounced vault of the palate, the alveoli and tubercles have an average degree of atrophy, the mobile mucous part is located slightly closer to the apex of the alveolar. A less advantageous type, however, still suitable for securing a prosthesis.
Third- structures are flattened, which makes reliable fixation of the prosthesis almost impossible - there are no anatomical irregularities for its reliable fastening, so the prosthesis is constantly shifting.

Thus, the division in this classification is quite arbitrary, since it has a significant number of intermediate options.

According to Keller

In contrast to the conditions for installing structures on the upper jaw, providing the lower jaw with a prosthesis is, in principle, unfavorable.

The lower jaw is mobile - it takes part in speech, in chewing food, in facial expressions, and therefore normal human life involves many situations for the displacement of the prosthesis.

Keller's classification specializes in describing the degree of atrophy of the mandibular structures:

The first type describes cases of minor, evenly distributed atrophic changes.
This type is very rare for the reason that uniform atrophy is only possible if all teeth have been recently removed simultaneously. However, it is precisely this that is most beneficial for prosthetics.
In the second type, structures are subject to significant uniform changes. With such changes, the alveolar part becomes narrow and sharp, and it becomes almost impossible to attach the prosthesis to it.
In addition, the anatomical smoothing of the structures does not interfere with the displacement of the prosthesis, which makes it extremely unstable when worn. Sometimes prosthetics with this type are simply painful for patients.
In the case of the third type, atrophy affects the lateral parts to a greater extent and the anterior parts to a lesser extent.
Unlike the previous one, this type is more beneficial for prosthetics, since the intact alveolar part gives the prosthesis stability, and atrophic changes the lateral sections create a concave relief, preventing the prosthesis from sliding.
The last, fourth type describes the case opposite to the previous one - with pronounced atrophy in the anterior section and slight atrophy in the lateral sections.
It is almost impossible to install a stably fixed prosthesis in this situation, since it will constantly shift in the anteroposterior direction, “slipping” out of the oral cavity.

As a result, the lower jaw is much more difficult to install and wear a complete denture, and the optimal option for the operation is extremely rare.

According to Oksman

Oksman, combining the developments of his predecessors, created a classification for both jaws at once. The scientist identified the following types of abnormal changes:

Type I The alveoli are well preserved, the palatine vault is clear, the mucous membrane is mobile high points fastenings
II type. All structures are subject to moderate atrophy, the contours are smoothed.
III type. The structures have a significant degree of atrophy, evenly distributed throughout the bone, and the palatine vault is significantly flattened.
IV type. Uneven distribution of structural changes, a combination of signs of several types.

As you can guess from the previous classifications, the best option for installing a complete denture is the first one, while the least successful are the third and fourth, although in the latter case the degree and localization of the unevenness of changes is important.

Changes in the structure of the lower jaw can also be divided into 4 types. Their principle is similar to the classification for the upper jaw. The first 3 points describe uniform atrophic changes in the order of their intensification, and the last one is necessary to describe cases of confusion of signs inherent in different types.

As you can see, Oksman in his classification decided to move away from careful detailing of the characteristics inherent in each type, and introduce a type with new characteristics - mixed, which would include all cases of uneven atrophy.

Proposals of Kurlyandsky and Doinikov

Kurlyandsky's classification is essentially an improved version of Schröder's classification. It is also devoted to the upper edentulous jaws and general outline repeats the description of types.

An innovation that makes it possible to distinguish it as an independent theoretical education is the introduction of the concept of torus, i.e. thickening of the palatal suture. Accordingly, the thicker the torus, the less favorable the prognosis for the installation of a prosthesis.

Doynikov also worked to improve Schroeder's classification. Instead of changing the points in the original, the scientist introduced two additional types into it.

The fourth type is considered to be jaws with pronounced alveoli in the anterior part and smoothed ones in the lateral parts. Accordingly, the last type in the classification describes the opposite situation: severe atrophy in the anterior part, and moderate atrophy in the lateral parts.

Types of casts

One of the guarantees of reliable and high-quality prosthetics is taking a good impression of the tissues of the prosthetic bed.

This is necessary for the manufacture of any prosthetic structure, ensuring its compatibility with the type of prosthetic jaw of the patient.

There are several types of prints, which are divided according to various reasons.

Anatomical impression has the highest edges, due to which the moving tissues overlap as far as possible. They are obtained using standard impression trays.

Another type of imprint - functional. It is removed using an individual impression tray, it has lower edges and is limited to the mobile mucosa, overlapping it only to a small extent.

There are, in fact, functional and functional suction types of impressions, which differ in the degree of coverage of moving tissues.

Functional suction the impression covers moving tissue to a lesser extent.

Unloading and loading(compression) impressions differ in the degree to which the mucous membrane is squeezed out during production.

In accordance with the names, the unloading impression is removed with minimal pressure, while the compression impression is made with more pressure. The choice of impression depends on the type of mucous membrane of the prosthetic bed.

Features of the mucous membrane

It is important to assess the condition of the mucosa even at the stage of taking an impression. The choice of material used depends on this factor.

The following types of mucosa are distinguished:

Normal mucous membrane is well hydrated, has a pale pink color and is practically not injured during manipulations performed with it. This is the state of the mucosa that is optimal for prosthetics.
Hypertrophied shell when touched, it feels loose, hot, it is well moisturized, but is easily damaged during manipulation. Such a shell is characterized as very pliable, and it is difficult to fix the prosthesis on it.
Atrophied shell it is very dense and dry to the touch, has a whitish color. This type is the least favorable for prosthetics.
Inflammation and damage can often be found on this type of membrane, and if present, it is necessary to differentiate it from infectious and systemic diseases.

Thus, the condition of the mucosa must be taken into account when installing a prosthesis in the same way as other signs of atrophy.

Additional information on the topic of the article is presented in the video.

Conclusion

Of course, prosthetics in case of loss of all teeth is a complex and expensive process that requires professionalism and careful control at all stages of the procedure. Many people are afraid of the cost of this procedure, but what if the patient refuses prosthetics?

As already mentioned in the above classifications, the alveolar processes tend to smooth out quite quickly if teeth are not attached to them.

If the patient postpones prosthetics, every day this decision will become more and more difficult to implement, since the relief of the jaw and oral cavity as a whole will irreversibly change.

In addition, prosthetics can restore aesthetics to a person’s smile, and therefore self-confidence. At first, some defects in facial expressions and conversation are possible, but they disappear a month after prosthetics, while the absence of teeth only aggravates the situation over time.

Losing teeth does not leave its mark on the entire body: particles of poorly chewed or overly soft food can provoke diseases of the gastrointestinal tract, and malocclusion leads to arthritis of the temporomandibular joint, which results in constant headaches and poor health.

Don’t put off prosthetics and trust yourself only in the hands of a professional!

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For practical reasons, it became necessary to classify edentulous jaws. The proposed classifications to a certain extent determine the treatment plan, promote mutual understanding between doctors and facilitate recording in the medical history. When encountering indications of a particular type of toothless jaw, the doctor clearly understands what typical difficulties he may encounter. Of course, none of the known classifications claims to be an exhaustive description of toothless jaws, since there are transitional forms between their extreme types.

Schroeder distinguishes three types of upper toothless jaws (Fig. 186). The first type is characterized by a well-preserved alveolar process, well-defined alveolar cusps and a high palatal vault. The transitional fold, the places of attachment of muscles, folds of the mucous membrane are located relatively high. This type of edentulous upper jaw is most favorable for prosthetics, since there are well-defined points of anatomical retention (high arch of the palate, pronounced alveolar process and maxillary tuberosities and high points of attachment of muscles and folds of the mucous membrane that do not interfere with the fixation of the prosthesis).

In the second type, an average degree of atrophy of the alveolar process is observed. The alveolar process and alveolar cusps are still preserved, the palatine vault is clearly defined. The transitional fold is located somewhat closer to the apex of the alveolar process than in the first type. With a sharp contraction of the facial muscles, the fixation of the prosthesis may be disrupted.

The third type of toothless upper jaw is characterized by severe atrophy: alveolar processes and tubercles are absent, the palate is flat. The transitional fold is located in the same horizontal plane with the hard palate. When prosthetics of this type of toothless jaw are created, significant difficulties are created, since in the absence of the alveolar process and alveolar tubercles, the prosthesis acquires significant freedom for anterior and lateral shifts when chewing food, and the low attachment of the frenulum and transitional fold contributes to the shedding of the prosthesis.

Keller (Kohler) distinguishes four types of toothless lower jaws (Fig. 187). In the first type, the alveolar processes are slightly and uniformly atrophied. In this case, the evenly rounded alveolar ridge is a good basis for the prosthesis and limits its freedom of movement when moving forward and to the sides. The attachment points of the muscles and folds of the mucous membrane are located at the base of the alveolar process. This type of jaw is observed when the teeth are removed at the same time and the atrophy of the alveolar process occurs slowly. It is most convenient for prosthetics, although it is relatively rare.

In the second type, there is pronounced but uniform atrophy of the alveolar process. In this case, the alveolar ridge barely rises above the floor of the oral cavity, representing in the anterior section a narrow, sometimes even sharp, knife-like formation, which is not very suitable as a base for a prosthesis. The muscle attachment sites are located almost at the level of the ridge. This type of edentulous lower jaw presents great difficulties for prosthetics and obtaining a stable functional result, since there are no conditions for anatomical retention, and the high location of muscle attachment points during their contraction leads to displacement of the prosthesis from its bed. In this case, the use of a prosthesis is often painful due to the sharp edge of the internal oblique line, and the success of prosthetics is achieved in some cases only after its smoothing.

The third type is characterized by pronounced atrophy of the alveolar process in the lateral sections with relatively preserved alveolar process in the anterior section. This type of alveolar ridge occurs when the lateral teeth are removed early. It is relatively favorable for prosthetics, since in the lateral sections between the external and internal oblique lines there are flat, almost concave surfaces, free from points of muscle attachment, and the presence of a preserved alveolar process in the anterior part of the jaw protects the prosthesis from displacement in the anteroposterior direction.

In the fourth type, atrophy of the alveolar process is most pronounced in the front, with its relative preservation in the lateral parts of the lower jaw. As a result, the prosthesis loses support in the anterior region and slides forward.

I.M. Oksman proposed a unified classification for the upper and lower toothless jaws (Fig. 188). According to his classification, there are four types of toothless jaws. In the first type, there is a high alveolar process, high maxillary cusps of the jaw, a pronounced arch of the palate and a high location of the transitional fold and points of attachment of the frenulum and buccal cords. In the second type, there is moderate atrophy of the alveolar process and maxillary tuberosities, a shallower palate and lower attachment of the mobile mucous membrane. In the third type, there is a sharp but uniform atrophy of the alveolar process and maxillary tuberosities, and flattening of the palatine vault. The mobile mucous membrane is attached at the level of the apex of the alveolar process. The fourth type is characterized by uneven atrophy of the alveolar process, that is, it combines various signs of the first, second and third types.

The first type of edentulous lower jaw is characterized by a high alveolar process, a low location of the transitional fold and points of attachment of the frenulum and buccal folds of the mucous membrane. In the second type, there is moderate, uniform atrophy of the alveolar process. In the third type of toothless jaw, the alveolar process is absent or poorly represented. Atrophy can also affect the body of the jaw. With the fourth type of lower toothless jaw, uneven atrophy of the alveolar process is noted, which is a consequence of the removal of teeth at different times.

Schröder proposed to distinguish 3 types of atrophy of the alveolar processes of edentulous upper jaws.

. First type is characterized by well-defined points of anatomical retention: a high arch of the palate, pronounced alveolar process and tubercles of the upper jaw, high points of attachment of muscles and folds of the mucous membrane, which do not interfere with the fixation of the prosthesis. This type of toothless upper jaw is most favorable for prosthetics.

. Second type- there is an average degree of atrophy of the alveolar process. The latter and the cusps of the upper jaw are still preserved, the palatine vault is clearly defined. The transitional fold is located somewhat closer to the apex of the alveolar process than in the first type. With a sharp contraction of the facial muscles, it can be disrupted.

. Third type The edentulous upper jaw is characterized by significant atrophy: alveolar processes and tubercles are absent, the palate is flat. The transitional fold is located in the same horizontal plane with the hard palate. When prosthetizing such a toothless jaw, great difficulties are created, since in the absence of the alveolar process and tubercles of the upper jaw, the prosthesis gains freedom of movement when chewing food, and the low attachment of the frenulum and transitional fold contributes to the shedding of the prosthesis and poor fixation and stabilization.

The anatomical and physiological features of the lower jaw differ significantly from those of the upper jaw. The conditions for the manufacture and use of removable dentures on the lower jaw are less favorable.

L. Keller proposed 4 types of atrophy of the lower edentulous jaws.

. With the first type the alveolar part of the lower jaw is slightly and uniformly atrophied. The evenly rounded alveolar ridge is a convenient base for the prosthesis and limits freedom of movement when it is moved forward and to the side. The attachment points of the muscles and folds of the mucous membrane are located at the base of the alveolar part. This type of jaw occurs if the teeth are removed at the same time and the atrophy of the alveolar part occurs slowly. It is most convenient for prosthetics, although it is observed relatively rarely.

. With the second type a pronounced but uniform atrophy of the alveolar part is noted, while the alveolar part rises above the floor of the oral cavity, representing in the anterior section a narrow, sometimes even sharp, like a knife, formation, unsuitable for the base of a prosthesis. The muscle attachment sites are located almost at the level of the apex of the alveolar part. This type of edentulous lower jaw presents great difficulties for prosthetics and obtaining a stable functional result, since there are no conditions for anatomical retention, and the absence of a deep transitional fold and the high location of muscle attachment points during their contraction lead to displacement of the prosthesis. Using a prosthesis is often painful due to the sharp edge of the maxillary-hyoid line, and prosthetics in some cases are successful only after smoothing it.

. For the third type characterized by pronounced atrophy of the alveolar part in the lateral sections with relatively preserved alveolar part in the anterior section. Such a toothless jaw is formed with the early removal of chewing teeth. This type is relatively favorable for prosthetics, since in the lateral sections between the oblique and mylohyoid lines there are flat, almost concave surfaces, free from muscle attachment points, and the presence of a preserved alveolar part in the anterior part of the jaw protects the prosthesis from displacement in the anteroposterior direction.

. With the fourth type atrophy of the alveolar part of the jaw is most pronounced in the front, with its relative preservation in the lateral sections. As a result, the prosthesis loses support in the anterior region and slides forward.

A.I. Doynikov proposed a unified classification of toothless jaws for the upper and lower jaws with an emphasis on the unevenness of atrophy and identified five degrees of atrophy.

. First degree- on both jaws there are well-defined alveolar ridges, covered with a slightly pliable mucous membrane. The palate is covered with a uniform layer of mucous membrane, moderately pliable in its posterior third. Natural folds of the mucous membrane (frena of the lips, tongue, buccal cords) are sufficiently distant from the top of the alveolar process and the alveolar part of the jaws.

- First degree is a convenient support for a prosthesis, including.

. Second degree(moderate degree of atrophy of the alveolar ridges) is characterized by moderately pronounced maxillary tuberosities, average depth of the palate and a pronounced torus.

. Third degree - complete absence alveolar process and alveolar part of the jaws, sharply reduced dimensions of the jaw body and maxillary tubercle, flat palate, wide torus.

. Fourth degree- pronounced alveolar ridge in the anterior area and significant atrophy in the lateral parts of the jaws.

.Fifth degree- pronounced alveolar ridge in the lateral sections and significant atrophy in the anterior section of the edentulous jaws.

This classification is most convenient in the practice of an orthopedic doctor; it covers the largest number clinical cases, reflects the true picture of the degree and localization of jaw atrophy.

Features of the structure of the mucous membrane of the prosthetic bed

The mucous membrane of the prosthetic bed is characterized by a certain degree of compliance, mobility and sensitivity. There are 3 types of mucous membrane:

. first type- normal: characterized by moderate pliability, well moisturized, pale pink in color, minimally vulnerable. Most favorable for fixing prostheses;

. second type- hypertrophied: characterized by a large amount of intermediate substance. On palpation it is loose, hyperemic, well moisturized, and relatively easily vulnerable. With such a mucous membrane, it is not difficult to create a valve, but the prosthesis on it will be mobile due to its great compliance;

. third type- atrophied: very dense, whitish in color, dry. This type of mucous membrane is the most unfavorable for prosthetics. The mucous membrane covering the alveolar process of the upper jaw is fixedly connected to the periosteum and consists almost throughout its entire length of stratified squamous epithelium and its own layer. The epithelium in the area of the alveolar process has a stratum corneum.

In the anterior third of the hard palate The mucous membrane mainly consists of stratified squamous epithelium, its own and submucosal layers. The mucous membrane, located in the area of the palatine suture, consists of stratified squamous epithelium and its own layer. It is tightly fused with the periosteum, immobile, thin, and easily injured. The mucous membrane, located between the palatine eminence, line A and limited on the lateral side by the lateral sections of the alveolar process, has a large number blood vessels. Its thickness is not the same in different areas. The thickest layer of the mucous membrane is located near the transition of the hard palate to the soft palate, within the area of the second and third molars. The thinnest layer of mucous membrane is located in the premolar area. The mucous membrane, located in the area of the transition of the hard palate to the soft palate, consists of its own layer, submucosal layer and stratified squamous epithelium, which does not have a stratum corneum. The submucosal layer contains a large number of mucous glands. The mucous membrane at the junction with upper lip and cheeks on the alveolar process consists of multilayered squamous epithelium (without the stratum corneum), its own and submucosal layers. Since it is located not on the bone base, but on facial muscles, then it is functionally mobile.

Mucous membrane of the alveolar part of the lower jaw basically has the same histological structure, as on the upper jaw, however, its thickness is somewhat less, and just like on the upper jaw, it is thinner in the anterior section and increases in the area of the lateral teeth. In the area of the geniohyoid torus, the mucous membrane is the thinnest and consists of stratified squamous epithelium and its own layer, directly fused with the periosteum.

In the retromolar region The mucous membrane consists of three layers; in its submucosal layer there are a large number of fat cells.

In the posterior alveolar region, the mucous membrane contains a loose submucosal layer rich in fat and mucous cells. The thickness of the mucous membrane can be determined with great accuracy directly on the patient.

Based on the degree of mobility, the oral mucosa is divided into mobile and immobile (more precisely, passively mobile). Mobile mucous membrane Covers the cheeks, lips and floor of the mouth. It has a loose submucosal layer containing fatty inclusions, many vessels, and a significant amount of elastic fibers, so it easily folds and can move in horizontal and vertical directions.

Fixed mucous membrane covers the alveolar process and hard palate. In the area of the median palatine suture, it is attached without a submucosal layer to the periosteum, in the lateral and posterior parts of the hard palate and contains a large number of mucous glands, does not form a fold and moves only under pressure towards the periosteum.

The area of the mucous membrane located in the area of the transition of the mobile mucosa to the passively mobile one is called transitional fold.

When determining the boundaries of removable dentures, it is necessary to distinguish neutral zone- the border area between the mobile and immobile mucous membrane. The neutral zone does not coincide with the transitional fold, but is located below it on the upper jaw, and above it on the lower jaw. This area is characterized by minimal mobility and pronounced pliability of the mucous membrane (Fig. 4-2).

Rice. 4-2. Border area between the mobile and immobile mucous membrane (neutral zone): a - mobile mucous membrane; b - immobile mucous membrane; V - apex of the alveolar ridge;

From the oral surface, the neutral zone on the upper jaw passes in the area of the transition of the hard palate to the soft palate, often capturing the so-called vibrating zone.

Vibrating zone- a section of the mucous membrane that is revealed when pronouncing the sound “A”. The width of the passively mobile mucous membrane in the area of line A reaches, according to S.I. Gorodetsky (1951), 6 mm. The shape and width of the vibrating zone are of great importance in determining the distal border of the maxillary denture.

Neutral zone on the lower jaw of A.I. Betelman (1965) divided into oral and vestibular regions. The oral region of the neutral zone can be divided into sublingual, retroalveolar and retromolar regions, according to the anatomical regions in which they pass.

The sublingual region is the space enclosed between the lower surface of the tongue, the floor of the mouth and the alveolar processes and the alveolar part of the lower jaw. Along the midline in the sublingual region there is a frenulum of the tongue, on both sides of which there are sublingual folds of the mucous membrane. In the center of the sublingual space, a bone growth is often noted - the geniohyoid torus - the place of attachment of the geniohyoid and genioglossus muscles, which occurs in 33% of cases (Kurlyandsky V.Yu., 1958). The lateral portion of the sublingual region borders posteriorly with the posterior alveolar region. The shape and size of the hyoid portion of the neutral zone depend on the function of the muscles that lower the mandible, and mainly on the mylohyoid muscle, which is attached to the internal oblique line. The boundaries of the posterior alveolar region: above - the anterior palatine arch, below - the floor of the mouth, outside - the body of the lower jaw, inside - the lateral surface of the tongue. A feature of this area is the presence of a large number of muscles (superior pharyngeal constrictor, palatoglossus, mylohyoid, styloglossus), which, when contracted, reduce the neutral zone.

Retromolar area: medially and laterally limited by the external oblique and mylohyoid ridges, between which in the middle part of the zone there is a mucous tubercle consisting mainly of connective tissue. The apex of the tubercle corresponds to the distal edge of the socket of teeth 3.8 and 4.8. In the posterior sections, the mucous tubercle is limited by the pterygomaxillary fold and the buccal muscle. Fibers are connected to the lingual side of the tubercle temporal muscle and superior pharyngeal constrictor, so the neutral zone will be located within the maxillo-lingual line.

The upper and lower jaws are covered with a fixed mucous membrane, which has unequal compliance in different parts of the jaw.

The pliability of the mucous membrane refers to its ability to shrink under pressure and restore its original shape after the load is removed.

Taking into account the pliability of the mucous membrane, Lund (1924) proposed to distinguish 4 zones on the hard palate.

. I zone- the area of the sagittal suture (medial fibrous zone), characterized by a thin mucous membrane devoid of a submucosal layer,

Directly attached to the periosteum. Has minimal flexibility.

. II zone- the alveolar process and the adjacent narrow strip, expanding towards the molars (peripheral fibrous zone), are covered with a thin, non-compliant mucous membrane with a minimal submucosal layer.

. III zone- the area of the upper jaw in the area of the palatine folds (fatty zone), covered with a mucous membrane with a submucosal layer, which contains a large number of fat cells. Has good flexibility.

. IV zone- the back part of the hard palate (glandular zone), has a submucosal layer rich in mucous glands and some adipose tissue. Has significant flexibility.

E.I. Gavrilov (1962) believes that the pliability of the mucous membrane can be explained by the presence of a dense vascular network in the submucosal layer, which he called the buffer zone, and not by the presence of adipose and glandular tissue. The ability of the vessels to be freed from blood at elevated pressure and refilled with it when it is removed determines the pliability of the mucous membrane. In the area of the alveolar processes and in the midline (torus), the vascular network is not expressed, therefore the mucous membrane covering this area does not have buffering properties. The buffering properties of the mucous membrane in the area of the transverse palatine folds and the posterior third of the hard palate are well expressed.

The degree of pliability of the mucous membrane can be roughly determined using a finger, probe handle or mirror, but for a more precise determination there are special instruments.

Knowing the degree of pliability of the oral mucosa is of particular practical importance. Depending on the pliability of the mucous membrane, the doctor chooses the method of obtaining a functional impression and the degree of fluidity of the impression material. For example, if there is a sharp discrepancy in the degree of compliance in different areas of the prosthetic bed, it is recommended to obtain a functional impression using flowable impression materials (silicone and polysulfide) with differentiated pressure on the underlying tissue.

Supple pays the main attention to the condition of the mucous membrane of the prosthetic bed and identifies 4 classes of compliance:

. 1st class- on both jaws there are well-defined alveolar ridges, covered with a slightly pliable mucous membrane. The palate is covered with a uniform layer of mucous membrane, moderately pliable in its posterior third. Natural folds of the mucous membrane (frena of the lips, tongue, buccal cords) are sufficiently distant from the top of the alveolar ridge. This class of mucous membrane is a convenient support for a prosthesis, including those with a metal base.

. 2nd class- the mucous membrane is atrophied, covering the alveolar ridges and palate with a thin layer. The attachment points of natural folds are located closer to the top of the alveolar ridge. Dense and thinned mucous membrane is less convenient for supporting a removable denture, especially with a metal base.

. 3rd grade- the alveolar part of the lower jaw and the posterior third of the hard palate are covered with loosened mucous membrane. This condition of the mucous membrane is often combined with a low alveolar part. Patients with such changes sometimes require pre-treatment. After prosthetics, they should especially strictly observe the regime for using the prosthesis and must be observed by a doctor.

.4th grade- movable strands of the mucous membrane are located longitudinally and easily move with slight pressure from the impression mass. The bands may become pinched, making it difficult or impossible to use the prosthesis. Such folds are more often observed on the lower jaw, mainly in the absence of the alveolar part. The alveolar edge with a dangling soft ridge belongs to the same type. In this case, prosthetics sometimes become possible only after its excision.

It is believed that when analyzing the mucous membrane, it is necessary to take into account the human constitution and the general condition of the body.

N.V. Kalinina distinguishes 4 types of mucous membrane depending on the constitution and general condition body:

. Type I- the mucous membrane perceives chewing pressure well. Such a mucous membrane often occurs in healthy people, normosthenics, regardless of age. Atrophy of the alveolar process and alveolar part is usually minor.

. Type II- thin mucous membrane, characteristic of people of asthenic constitution, more often women, occurs when varying degrees atrophy of the alveolar part and alveolar process and in elderly and elderly people with a significant degree of jaw atrophy.

. III type- loose, pliable mucous membrane, found mainly in hypersthenics, as well as in people with general somatic diseases. Most often these are violations from of cardio-vascular system, diabetes, mental illness.

. IV type- characterized by the presence of a mobile mucous membrane located within the alveolar ridges. It is observed in people with periodontitis, and can often be the result of trauma or atrophy of the alveolar ridge due to high blood pressure from the side of the prosthesis.

Edentia or absence of teeth in both jaws is a fairly common situation that can occur not only in elderly patients, but also in fairly young people.

This pathology requires immediate elimination, both due to the lack of aesthetics of the oral cavity and due to the possibility of developing a large number of complications.

However, to choose the right treatment tactics, a specialist needs to correctly study the structural features of the patient’s jaw with missing teeth, which is greatly simplified when using the classifications of toothless jaws available in dental practice.

General overview

Classifications of edentulous jaws play an important role in dental science. They allow specialists to adhere to uniform terminology and features of determining existing anomalies in the structure of the dentofacial rows.

Thanks to generally accepted classification criteria developed by renowned scientists and doctors of medical sciences, orthopedic specialists are able to accurately draw up a plan further treatment and determine in advance what problems may be encountered during therapeutic activities.

Types and features

There is still no single comprehensive classification of toothless jaws. This is due to the fact that in addition to the marginal forms of jaws named in the known groups, there are many transitional types that have certain structural features.

Currently, the most popular are five groups of toothless jaws, named after the developers.