Adentia teeth types. Complete secondary edentulous. Features of the treatment of pathology in children

The term "adentia" is not the most common in dentistry, so not every patient understands what is at stake on the first try. The phenomenon of adentia - congenital or acquired absence of teeth - is not so rare. Complete adentia (absence of all teeth) is rare, and partial (with the loss of several) is common. Is it necessary to treat adentia or can it be considered as a cosmetic defect?

What is adentia

Adentia is the complete or partial absence of permanent or milk teeth. There are several types of adentia:

• complete;
• partial;
• primary;
• secondary.

If you analyze this list, you can see the classification pattern according to the principle of appearance - primary (the second name is congenital) and secondary (in another way - acquired) and by the type of prevalence (full or partial). The causes of adentia are not fully understood. It is believed that it occurs after the resorption of the follicle, which occurs under the influence of general diseases or inflammation.

Adentia of permanent teeth may appear as a complication for milk teeth, especially if the latter were not treated on time and of poor quality. Doctors do not exclude the hereditary factor, problems in the endocrine system, as a result of which deviations occur during the formation of tooth germs. In most cases, in the presence of adentia, patients may experience abnormal formation of nails, hair and other organs of actodermal origin.

There is a pattern in the absence of some permanent teeth - lateral incisors, lower premolars, wisdom teeth. According to statistics, dentists do not observe second incisors in 0.9%. The rudiments of the second lower premolar are absent in 0.5% of children. The reasons for this phenomenon are explained by the fact that the masticatory apparatus in modern conditions does not have such a serious load as that of distant ancestors. Evolution has changed the size of the jaw, the number of rudiments of permanent teeth, since there is no place for them in the changed jaw - the reduction of the jaw leads to the reduction of teeth.

With a symmetrical incomplete number of teeth, the role of hereditary factors is great. There are cases when the tooth germs are everything, but some of them do not erupt, remaining retained in the alveolar bone. This fact is also confirmed by radiography. In a milk bite, this phenomenon is rare. An impacted tooth can create many problems for the jaw: displacement of adjacent teeth, deformation of adjacent roots. Often such a tooth causes pain of a neuralgic nature, can serve as a source of focal infection.

In childhood, it is necessary to take into account the likelihood of teething with a delay, sometimes beyond the physiological period. The tooth may be delayed due to lack of space in the dentition. Timely orthodontic intervention is important here.

Genuine adentia must be distinguished from retention - a delay in tooth growth after the prescribed one. Retention can cause vitamin, hormonal disorders, hereditary factor. As a rule, impacted teeth are displaced. Sometimes, even after decades, they still erupt. This process can be stimulated by orthopedic intervention. Retention causes deformation of the jaw, changes in the position of adjacent teeth, pressure from a displaced tooth on a neighboring root causes pulp atrophy, suppuration, root resorption (destruction of its tissues), so it is important to control this process.

Primary full

Complete primary adentia is a very serious anomaly, which, fortunately, is very rare. It occurs in the bite of milk or permanent teeth. The patient is completely devoid of the rudiments of all permanent teeth. This condition inevitably provokes violations of the symmetry of the face. At the same time, the alveolar processes of both jaws develop incorrectly. The mucous membrane of the oral cavity is pale and dry.

With adentia of milk teeth, there are no rudiments of them at all; when feeling the jaw, this is easy to diagnose. On the radiograph, the rudiments of milk teeth are completely absent, and the jaws are underdeveloped, which causes a strong decrease in the lower part of the face.

Adentia of permanent teeth is usually detected when changing milk to permanent. On the radiograph, the doctor observes the absence of the rudiments of permanent teeth, pulling the lower jaw to the upper, followed by asymmetry of the face.

Primary partial

Primary partial adentia is much more common than complete. In the dentition with this form, several or one milk or permanent teeth are missing. On the radiograph, there are no rudiments of missing teeth, and gaps appear between the erupted teeth - three. If a significant part of the teeth is missing in the dentition, then the jaw is formed underdeveloped.

Partial adentia is symmetrical and asymmetrical. With symmetrical adentia, there are no teeth of the same name on the right and left in the dentition - for example, the right and left incisors. With asymmetric - there are no opposite teeth from different sides.

What is it and when is dental implantation impossible without it.

Jaw cyst: what is this disease and how dangerous it is, read in.

Secondary complete

Secondary adentia has a different name - acquired. Teeth in the dentition are completely absent in the secondary form, both on the upper and lower jaws. Secondary adentia occurs in both permanent and milk teeth. This phenomenon is observed after the loss or extraction of teeth.

With complete secondary adentia, there are no teeth at all in the patient's mouth, so the lower jaw approaches the nose, and the soft tissues of the mouth area noticeably sink. With complete secondary adentia, the alveolar processes and the body of the jaw atrophy. The patient cannot bite off or chew food, he is not able to clearly pronounce sounds.

Secondary partial

Partial secondary adentia is the more common form. With this disease, there are no several (or one) milk or permanent teeth in the dentition. With insufficient tooth enamel, the hard tissues of the tooth are erased, causing hyperesthesia. The disease makes it difficult to eat hot or cold food, forming a habit of liquid food that does not need to be chewed. In the photo - adentia is complete and partial, adentia in children.

Symptoms of adentia

Symptoms of adentia are simple - complete or partial absence of teeth. In addition to the direct symptom, there are also indirect ones:

• reduction of one or both jaws;
• retraction of soft tissues of the oral part of the face;
• atrophy of the alveolar processes;
• formation of a network of wrinkles near the mouth;
• atrophied muscles in the mouth area;
• blunting of the angle of the jaw.

With partial adentia, a deep (distorted) bite is formed. The teeth gradually move towards the missing ones. In the area where there are no antagonistic teeth, the dentoalveolar processes of healthy teeth lengthen.

Diagnosis of adentia

Diagnosing adentia is not difficult. When examining the patient's oral cavity, the dentist notes the complete or partial absence of teeth in a row. An X-ray examination of both jaws is mandatory, especially in case of primary adentia, since only in the picture can one see the absence of the rudiments of permanent or milk teeth.

When diagnosing adentia in children, a panoramic X-ray of the jaw is made - it is she who allows you to determine the absence of the rudiments of teeth, the structure of the roots of the teeth and the bone tissue of the alveolar process.

When diagnosing, it is necessary to exclude factors that do not allow urgent. The dentist highlights the following points:

• the presence of unremoved roots, covered with mucous;
• the presence of exostoses;
• the presence of tumors and inflammation;
• the presence of diseases of the oral mucosa.

After the final elimination of all provoking factors, prosthetics can begin.

Treatment of adentia

The most effective method of treating adentia is orthopedic. The doctor draws up a treatment regimen based on the degree of atrophy of the alveolar processes and tubercles. In the treatment of primary adentia, depending on the age of the patient, they are registered for dispensary registration, and a pre-orthodontic trainer is installed for him.

With partial primary adentia in children, it is necessary to stimulate the correct dentition to prevent jaw deformation. When the seventh permanent teeth erupt, the dentist explores options for prosthetics of missing teeth:

• prosthetics with ceramic-metal crowns and inlays;
• production of an adhesive bridge;
• implantation of missing teeth.

Treatment of primary adentia in children with the help of prosthetics is carried out by prosthetics from the age of 3 years. Such children should be under the constant supervision of a specialist - due to the pressure of the prosthesis, there is a danger of impaired jaw growth in the baby.

In the treatment of secondary complete adentia, the dentist restores the functionality of the dentoalveolar system, preventing the development of complications and pathologies, and after restoration, he is engaged in prosthetics using removable plate dentures. In the treatment of secondary adentia, it is important to eliminate the cause that causes the pathological process that provokes adentia.

With complete adentia, preliminary implantation of teeth is carried out.

When treating adentia with prosthetics, complications are possible

• violation of the normal fixation of the prosthesis due to jaw atrophy;
• allergic reaction to denture material;
• inflammatory process;
• bedsore formation.

An important point is psychological assistance to patients experiencing psychological discomfort from tooth loss.

Consequences of adentia

• Adentia is a complex dental disease, and without proper treatment, the patient's quality of life can suffer markedly. With complete adentia, speech is impaired, it becomes inarticulate. The patient is unable to chew and bite off solid food. Malnutrition leads to gastrointestinal problems, beriberi.
• With the complete absence of teeth, the temporomandibular joint does not function properly, which often leads to the development of inflammatory processes.
• It is impossible not to take into account psychological discomfort, lowering the patient's social status, self-esteem. All this provokes regular stress and the occurrence of nervous disorders.

Adentia must be treated without fail, and without much thought.

Adentia in children is the partial or complete absence of teeth due to their loss or anomaly in the development of the dentition. The disease is characterized by a violation of the function of chewing and speech due to the lack of integrity of the dentition. In severe cases, adentia of teeth in children is accompanied by deformation of the facial skeleton and further loss of teeth. With the complete absence of teeth, there is often a displacement of the lower jaw towards the nose, retraction of the soft tissues of the preoral region, and the formation of wrinkles. With partial adentia in children, the remaining teeth are displaced and diverge. And in the process of chewing, an increased load falls on them.

Interesting fact!

The rudiments of milk teeth are formed in babies even in the womb, at about 3-4 months of her pregnancy. The process of their formation takes about a month, so it is important that during this period the expectant mother consumes dairy products rich in calcium, without which the full formation and subsequent health of the teeth is impossible.

Types of adentia in children

Adentia in children is divided into types in accordance with the criteria indicated in the table below.

Causes of adentia in children

Adentia in children can be hereditary, but it can also develop in the process of a child's life. In this regard, there are several causes of adentia in children.

• Absence or death of rudiments of teeth. This may be due to hereditary causes, as well as disorders in the formation of the fetus in the womb. The child's tooth plate is formed even in the prenatal period, and the impact of harmful factors (for example, poor ecology or unhealthy lifestyle of the mother) can negatively affect this process.
• Loss of teeth in the course of life. Children, especially boys, are more prone to injury than adults because of their activity. Thus, the teeth of babies often fall out during fights, falls, as well as certain sports (hockey, football, boxing).
• Deep caries and its complications. Due to the thin enamel of milk teeth, caries in children develops on them much faster than on permanent ones. Therefore, if it is not cured in a timely manner, there is a risk of losing a tooth as a result of progressive purulent-inflammatory processes in the tissues.

Photo of adentia in children

Treatment of adentia in children

Diagnosis of adentia of teeth in children is carried out by visual and palpation examination, targeted intraoral radiography and orthopantomography. The tactics of treating adentia in children is determined taking into account the physiological, anatomical and hygienic features of the child's dental system. Depending on the degree of the disease, the following methods of treating adentia in children are used.

Stimulation of teething. In some cases, a gum dissection procedure and the placement of special braces that stimulate eruption are used.

Fixed prosthetics. Fixed orthopedic structures (crowns, bridges) are installed for the child.

Removable prosthetics. Removable orthopedic constructions (clasp, laminar prostheses) are installed.

Dental implantation. It is applied only after the jaw bones are finally formed. This process usually ends at the age of 18 in boys and at 16-17 in girls. Until that time, the treatment of adentia is carried out with the use of removable and fixed prostheses.

Consequences of adentia in children

If you do not contact a specialist in time and do not treat adentia in children, this can lead to deformation of the facial skeleton, which results in developmental defects in the child.

• Speech disorder. With the complete or partial absence of teeth, the child pronounces some sounds incorrectly, and may even lose the ability to pronounce them.
• chewing dysfunction. Due to a decrease in the quality of chewing food and a change in the mode of consumption of products, the absence of teeth often leads to diseases of the gastrointestinal tract in a child.
• Mental disorders. The absence of teeth is also a cosmetic defect. The kid is embarrassed to smile, as a result, he develops complexes. In addition, a violation in the work of the jaws caused by adentia brings discomfort and causes a deterioration in mood.

Where to apply?

Treatment of complete or partial adentia in children is prescribed and carried out by an orthopedic dentist. The presence of teeth is an important aspect of a child’s health and psychological state, therefore, it is necessary to carefully approach the process of choosing a children’s dental clinic and study the range of services related to the treatment of adentia in children, which are offered by various medical institutions. Be sure to pay attention to the fact that dentistry has a license to provide services to children.

How much does the treatment cost?

Treatment of adentia in children begins with an initial examination and preparation of a treatment plan. Usually these services are provided free of charge - as a promotion to attract customers. Also, a small patient will need to do an x-ray at a price of 350 rubles and a panoramic x-ray of the oral cavity, the cost of which starts from 1,000 rubles. In addition, before starting the treatment of adentia in children, it is necessary to carry out professional oral hygiene at a price of 2,700 rubles and more. Based on the fact that adentia in children is treated mainly by installing removable dentures, parents should be prepared for the following costs for various types of orthopedic structures: a partially removable plate denture costs from 1,750 to 60,000 rubles, a complete removable plate denture - from 40,000 to 100,000 rubles, temporary full removable prosthesis - from 2,800 to 3,500 rubles. A removable acrylic prosthesis will cost from 12,000 rubles, a bridge - from 25,000 rubles. The cost usually includes the manufacture of the structure and its installation by a specialist.

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Adentia(adentia; a - prefix, meaning the absence of a sign, corresponds to the Russian prefix "without" + dens - tooth) - the absence of several or all teeth. There are acquired (as a result of a disease or injury), congenital hereditary adentia.

In the special literature, a number of other terms are used: defect of the dentition, absence of teeth, loss of teeth. Partial secondary adentia as an independent nosological form of damage to the dentoalveolar system is a disease of the dentition or both dentitions, characterized by a violation of the integrity of the dentition of the formed dentoalveolar system in the absence of pathological changes in the remaining links of this system.

With the loss of part of the teeth, all organs and tissues of the dentition can adapt to a given anatomical situation due to the compensatory capabilities of each organ of the system. However, after the loss of teeth, significant changes can occur in the system, which are classified as complications. These complications are discussed in other sections of the textbook.

In the definition of this nosological form, next to the classical term "adentia" is the definition of "secondary". This means that the tooth (teeth) is lost after the final formation of the dentoalveolar system as a result of a disease or injury, i.e., the concept of “secondary adentia” contains a differential diagnostic sign that the tooth (teeth) was formed normally, erupted and for some period functioned. It is necessary to single out this form of damage to the system, since a defect in the dentition can be observed with the death of the rudiments of the teeth and with a delay in eruption (retention).

Partial adentia, according to WHO, along with caries and periodontal diseases, is one of the most common diseases of the dentition. It affects up to 75% of the population in various regions of the globe.

An analysis of the study of dental orthopedic morbidity in the maxillofacial area according to the data of the appealability and planned preventive sanitation of the oral cavity shows that secondary partial adentia ranges from 40 to 75%. The prevalence of the disease and the number of missing teeth correlate with age.

In terms of frequency of removal, the first permanent molars occupy the first place. Rarely, the teeth of the anterior group are removed.

Etiology and pathogenesis

Among the etiological factors that cause partial adentia, it is necessary to distinguish congenital (primary) and acquired (secondary).

The causes of primary partial adentia are violations of the embryogenesis of dental tissues, as a result of which there are no rudiments of permanent teeth. This group of reasons should also include a violation of the eruption process, which leads to the formation of impacted teeth and, as a result, to primary partial adentia. Both of these factors can be inherited.

The most common causes of secondary partial adentia are caries and its complications - pulpitis and periodontitis, as well as periodontal disease - periodontitis. In some cases, the extraction of teeth is due to untimely treatment, resulting in the development of persistent inflammatory processes in the periapical tissues. In other cases, this is a consequence of incorrectly performed therapeutic treatment.

Sluggish, asymptomatic necrobiotic processes in the dental pulp with the development of granulomatous and cystogranulomatous processes in the periapical tissues, cyst formation in cases of a complex surgical approach for resection of the root apex, cystotomy or ectomy are indications for tooth extraction. Removal of teeth treated for caries and its complications is often caused by spalling or splitting of the crown and root of the tooth, weakened by a large mass of the filling due to a significant degree of destruction of the hard tissues of the crown.

Injuries to the teeth and jaws, chemical (acid) necrosis of hard tissues of the crowns of the teeth, surgical interventions for chronic inflammatory processes, benign and malignant neoplasms in the jaw bones also lead to the occurrence of secondary adentia. In accordance with the fundamental points of the diagnostic process in these situations, partial secondary adentia recedes into the background in the clinical picture of the disease.

Pathogenetic bases of partial secondary adentia as an independent form of damage to the dentition are due to large adaptive and compensatory mechanisms of the dentoalveolar system. The onset of the disease is associated with the extraction of a tooth and the formation of a defect in the dentition and, as a consequence of the latter, a change in the function of chewing.

Rice. 97. Changes in the functional links of the dentoalveolar system in adentia.
a - functional centers; 6 - non-functional links.

A single morphologically functional dentoalveolar system disintegrates in the presence of non-functioning teeth (these teeth are devoid of antagonists) and groups of teeth, the functional activity of which is increased (Fig. 97). Subjectively, a person who has lost one, two or even three teeth may not notice a violation of the function of chewing. However, despite the absence of subjective symptoms of damage to the dentition, significant changes occur in it.

Increasing over time, the quantitative loss of teeth leads to a change in the function of chewing. These changes depend on the topography of defects and the quantitative loss of teeth: in areas of the dentition where there are no antagonists, a person cannot chew or bite off food, these functions are performed by preserved groups of antagonists. The transfer of the biting function to a group of canines or premolars due to the loss of anterior teeth, and in case of loss of chewing teeth, the function of chewing to a group of premolars or even anterior group of teeth disrupts the functions of periodontal tissues, the muscular system, and elements of the temporomandibular joints.

So, in the case shown in Fig. 97, biting off food is possible in the region of the canine and premolars on the right and left, and chewing in the region of the premolars on the right and the second and third molars on the left.

If one of the groups of chewing teeth is missing, then the balancing side disappears; there is only a fixed functional center of chewing in the area of ​​the antagonistic group, i.e., the loss of teeth leads to a violation of the biomechanics of the lower jaw and periodontium, a violation of the patterns of intermittent activity of the functional centers of chewing.

With intact dentition, after biting off food, chewing occurs rhythmically, with a clear alternation of the working side in the right and left groups of chewing teeth. The alternation of the load phase with the rest phase (balancing side) causes a rhythmic connection to the functional load of periodontal tissues, characteristic contractile muscle activity and rhythmic functional loads on the joint.

With the loss of one of the groups of chewing teeth, the act of chewing takes on the character of a reflex given in a certain group. From the moment of the loss of a part of the teeth, a change in the function of chewing will determine the state of the entire dentoalveolar system and its individual links.

I. F. Bogoyavlensky (1976) points out that changes that develop under the influence of function in tissues and organs, including bones, are nothing but “functional restructuring”. It can proceed within the limits of physiological reactions. Physiological functional restructuring is characterized by such reactions as adaptation, full compensation and compensation at the limit.

The works of I. S. Rubinov proved that the effectiveness of chewing with various types of adentia is practically 80-100%. Adaptive-compensatory restructuring of the dentition, according to the analysis of masticograms, is characterized by some changes in the second phase of chewing, the search for the correct location of the food bolus, and a general lengthening of one complete chewing cycle. If normally, with intact dentition, it takes 13-14 s to chew the almond kernel (hazelnut) weighing 800 mg, then if the integrity of the dentition is violated, the time is extended to 30-40 s, depending on the number of lost teeth and remaining pairs of antagonists. Based on the fundamental provisions of the Pavlovsk school of physiology, I. S. Rubinov, B. N. Bynin, A. I. Betelman and other domestic dentists proved that in response to changes in the nature of chewing food with partial adentia, the secretory function of the salivary glands, stomach changes , food evacuation and intestinal peristalsis are slowed down. All this is nothing but a general biological adaptive reaction within the limits of the physiological functional restructuring of the entire digestive system.

Pathogenetic mechanisms of intrasystemic restructuring in secondary partial adentia according to the state of metabolic processes in the jaw bones were studied in an experiment on dogs. It turned out that in the early stages after partial extraction of teeth (3-6 months), in the absence of clinical and radiological changes, changes occur in the metabolism of the bone tissue of the jaws. These changes are characterized by an increased intensity of calcium metabolism compared to the norm. At the same time, in the jaw bones in the region of teeth without antagonists, the degree of severity of these changes is higher than at the level of teeth with preserved antagonists. An increase in the incorporation of radioactive calcium into the jawbone in the area of ​​functioning teeth occurs at the level of a practically unchanged content of total calcium (Fig. 98). In the area of ​​teeth that are out of function, a significant decrease in the content of ash residue and total calcium is determined, reflecting the development of initial signs of osteoporosis. At the same time, the content of total proteins also changes. A significant fluctuation in their level in the jawbone is characteristic, both at the level of functioning and non-functioning teeth. These changes are characterized by a significant decrease in the content of total proteins in the 1st month of the creation of an experimental model of secondary partial adentia, then a sharp rise in it (2nd month) and again a decrease (3rd month).

Consequently, the response of the jaw bone tissue to the changed conditions of the functional load on the periodontium is manifested in a change in the intensity of mineralization and protein metabolism. This reflects the general biological regularity of the vital activity of bone tissue under the influence of adverse factors, when mineral salts disappear, and the organic base, devoid of the mineral component, remains for some time in the form of osteoid tissue.

The mineral substances of the bone are quite labile and, under certain conditions, can be "extracted" and again "deposited" under favorable, compensated conditions or conditions. The protein base is responsible for the metabolic processes in the bone tissue and is an indicator of ongoing changes, regulates the processes of mineral deposition.

The established pattern of changes in the exchange of calcium and total proteins in the early periods of observation reflects the reaction of the jaw bone tissue to new conditions of functioning. Here, compensatory capabilities and adaptive reactions are manifested with the inclusion of all the protective mechanisms of bone tissue. During this initial period, with the elimination of functional dissociation in the dentition caused by secondary partial adentia, reverse processes develop, reflecting the normalization of metabolism in the bone tissue of the jaws [Milikevich V. Yu., 1984].

The duration of the action of unfavorable factors on the periodontium and jaw bones, such as increased functional load and complete shutdown from function, leads the dentoalveolar system to a state of "compensation at the limit", sub-decompensation. The dentoalveolar system with impaired integrity of the dentition should be considered as a system with a risk factor.

Clinical picture

Complaints of patients are of a different nature. They depend on the topography of the defect, the number of missing teeth, the age and gender of the patients.

The peculiarity of the studied nosological form is that it is never accompanied by a feeling of pain. In young and often in adulthood, the absence of 1-2 teeth does not cause any complaints from patients. Pathology is detected mainly during dispensary examinations, with planned sanitation of the oral cavity.

In the absence of incisors, fangs, complaints of an aesthetic defect, speech impairment, saliva splashing during conversation, and the inability to bite off food predominate. If there are no chewing teeth, patients complain of a violation of the act of chewing (this complaint becomes dominant only with a significant absence of teeth). More often, patients note inconvenience when chewing, the inability to chew food. Complaints about an aesthetic defect in the absence of premolars in the upper jaw are not uncommon. It is necessary to establish the reason for the extraction of teeth, since the latter is important for the overall assessment of the state of the dentoalveolar system and prognosis. Be sure to find out whether orthopedic treatment was previously carried out and what designs of dentures. The need to determine the general state of health at the moment is indisputable, which can undoubtedly affect the tactics of medical manipulations.

On physical examination, there are usually no facial symptoms. The absence of incisors and canines in the upper jaw is manifested by the symptom of "retraction" of the upper lip. With a significant absence of teeth, "retraction" of the soft tissues of the cheeks and lips is noted. Partial absence of teeth in both jaws without the preservation of antagonists is often accompanied by the development of angular cheilitis (jamming); during swallowing movement, the lower jaw makes a large amplitude of vertical movement.

When examining the tissues and organs of the mouth, it is necessary to carefully study the type of defect, its length (size), the condition of the mucous membrane, the presence of antagonizing pairs of teeth and their condition (hard tissues and periodontium), as well as the condition of the teeth without antagonists, the position of the lower jaw in central occlusion and in a state of physiological rest. The inspection must be supplemented with palpation, probing, determination of the stability of the teeth, etc. An X-ray examination of the periodontal teeth, which will be supporting for various designs of dentures, is mandatory.

The variety of options for secondary partial adentia, which have a significant impact on the choice of a particular treatment method, has been systematized by numerous authors.

The classification of dentition defects developed by Kenedy has become the most widespread, although it does not cover combinations that are possible in the clinic.

The author identifies four main classes. Class I is characterized by a defect that is bilateral distally not limited by teeth, II is characterized by a defect that is unilateral distally not limited by teeth; III - unilateral defect limited distally by teeth; Class IV - the absence of front teeth. All types of defects in the dentition without distal limitation are also called terminal, with distal limitation - included. Each defect class has a number of subclasses. The general principle of subclassing is the appearance of an additional defect inside the preserved dentition. This significantly affects the course of the clinical justification of tactics and the choice of one or another method of orthopedic treatment (type of denture).

Diagnosis

Diagnosis of secondary partial adentia is not difficult. The defect itself, its class and subclass, as well as the nature of the patient's complaints, testify to the nosological form. It is assumed that no other changes in the organs and tissues of the dentoalveolar system have been established by all additional laboratory research methods.

Based on this, the diagnosis can be formulated as follows:

Secondary partial adentia on the upper jaw, IV class, the first subclass according to Kenedy. Aesthetic and phonetic defect;
. secondary partial adentia on the lower jaw, class I, second subclass according to Kenedy. Chewing dysfunction.

In clinics where there are rooms for functional diagnostics, it is advisable to establish the percentage of loss of chewing efficiency according to Rubinov.

During the diagnostic process, it is necessary to differentiate primary from secondary adentia.

Primary adentia due to the absence of tooth rudiments is characterized by underdevelopment in this area of ​​the alveolar process, its flattening. Often, primary adentia is combined with diastemas and tremas, an anomaly in the shape of the teeth. Primary adentia with retention is usually diagnosed after an X-ray examination. It is possible to make a diagnosis after palpation, but with subsequent radiography.

Secondary partial adentia as an uncomplicated form should be differentiated from concomitant diseases, such as periodontal disease (without visible pathological tooth mobility and the absence of subjective discomfort), complicated by secondary adentia.

If secondary partial adentia is combined with pathological wear of the hard tissues of the crowns of the remaining teeth, it is fundamentally important to establish whether there is a decrease in the height of the lower face in the central occlusion. This significantly affects the treatment plan.

Diseases with pain syndrome in combination with secondary partial adentia, as a rule, become leading and are dealt with in the relevant chapters.

The rationale for the diagnosis of "secondary partial adentia" is the compensated state of the dentition after partial loss of teeth, which is determined by the absence of inflammation and dystrophic processes in the periodontium of each tooth, the absence of pathological abrasion of hard tissues, deformities of the dentition (Popov-Godna phenomenon, displacement of teeth due to periodontitis ). If the symptoms of these pathological processes are established, then the diagnosis changes. So, in the presence of deformations of the dentition, a diagnosis is made: partial secondary adentia, complicated by the Popov-Godon phenomenon; Naturally, the treatment plan and medical tactics of managing patients are already different.

Treatment

Treatment of secondary partial adentia is carried out with bridge-like, removable plate and clasp dentures.

A bridge-like and fixed prosthesis is a medical device that serves to replace the partial absence of teeth and restore chewing function. It is strengthened on natural teeth and transmits chewing pressure to the periodontium, which is regulated by the periodontal muscle reflex.

It is generally accepted that treatment with non-removable bridges can restore up to 85-100% chewing efficiency. With the help of these prostheses, it is possible to fully eliminate phonetic, aesthetic and morphological disorders of the dentoalveolar system. Almost complete compliance of the design of the prosthesis with the natural dentition creates the prerequisites for rapid adaptation of patients to them (from 2-3 to 7-10 days).

A removable lamellar prosthesis is a medical device that serves to replace the partial absence of teeth and restore chewing function. It is attached to natural teeth and transmits chewing pressure to the mucous membrane and bone tissue of the jaws, which is regulated by the gingivomuscular reflex (Fig. 101).

Taking into account the fact that the base of the removable laminar prosthesis completely relies on the mucous membrane, which, according to its histological structure, is not adapted to the perception of chewing pressure, chewing efficiency is restored by 60-80%. These prostheses allow to eliminate aesthetic and phonetic disorders in the dentoalveolar system.

However, the methods of fixation and a significant area of ​​the basis complicate the mechanism of adaptation, lengthen its period (up to 1–2 months).

A clasp prosthesis is a removable medical apparatus for replacing the partial absence of teeth and restoring chewing function.

It is strengthened behind natural teeth and relies both on natural teeth and on the mucous membrane, masticatory pressure is regulated in combination through periodontal and gingivomuscular reflexes.

The possibility of distribution and redistribution of masticatory pressure between the periodontium of the abutment teeth and the mucous membrane of the prosthetic bed, combined with the possibility of refusing to prepare teeth, high hygiene and functional efficiency, made these dentures one of the most common types of modern orthopedic treatment. Almost any defect in the dentition can be replaced by a clasp prosthesis, with the only caveat that with certain types of defects, the shape of the arch is changed.

In the process of biting off and chewing food, chewing pressure forces of various duration, magnitude and direction act on the teeth. Under the influence of these forces, responses occur in periodontal tissues and jaw bones.

Knowledge of these reactions, the influence of various types of dentures on them underlies the choice and reasonable use of one or another orthopedic apparatus (denture) for the treatment of a particular patient.

Based on this basic provision, the following clinical data significantly influence the choice of the design of the denture and abutment teeth in the treatment of partial secondary adentia: the class of the dentition defect; defect length; condition (tonus) of chewing muscles.

The final choice of treatment method can be influenced by the type of occlusion and some features associated with the profession of patients.

Lesions of the dentoalveolar system are very diverse, and there are no two patients with exactly the same defects. The main differences in the state of the dental systems of the two patients are the shape and size of the teeth, the type of occlusion, the topography of dentition defects, the nature of the functional relationships of the dentition in functionally oriented groups of teeth, the degree of compliance and the threshold of pain sensitivity of the mucous membrane of the edentulous areas of the alveolar processes and the hard palate, the shape and the size of the edentulous areas of the alveolar processes.

The general condition of the body must be taken into account when choosing the type of medical device. Each patient has individual characteristics, and in this regard, two outwardly identical in size and location of the defect of the dentition require a different clinical approach.

Theoretical and clinical basis for choosing a treatment method for fixed bridges

The term "bridge" came to orthopedic dentistry from technology during the period of rapid development of mechanics and physics and reflects the engineering structure - the bridge. It is known in the art that the design of a bridge is determined based on the expected theoretical load, i.e. its purpose, span length, ground conditions for supports, etc.

Almost the same problems are faced by an orthopedic doctor with a significant correction for the biological object of influence of the bridge structure. Any design of a dental bridge includes two or more supports (medial and distal) and an intermediate part (body) in the form of artificial teeth (Fig. 102).

Rice. 102. Varieties of fixed prostheses used for the treatment of secondary adentia.

The fundamentally different conditions for the statics of a bridge as an engineering structure and a fixed dental bridge are the following:

Bridge supports have a rigid, fixed base, while fixed bridge supports are mobile due to the elasticity of periodontal fibers, the vascular system, and the presence of a periodontal gap;
. the supports and span of the bridge experience only vertical axial loads in relation to the supports, while the periodontium of the teeth in the bridge-like non-removable denture experiences both vertical axial (axial) loads and loads at different angles to the axes of the supports due to the complex relief of the occlusal surface of the supports and the body of the bridge and the nature of the chewing movements of the lower jaw;

Rice. 103. Statics of the bridge as an engineering structure.

In the supports of the bridge and bridge prosthesis and the span after the load is removed, the internal stresses of compression and tension that have arisen subside (extinguish); the structure itself comes to a “calm” state;
. the supports of a fixed bridge prosthesis return to their original position after the load is removed, and since the load develops not only during chewing movements, but also when swallowing saliva and establishing dentition in central occlusion, these loads should be considered as cyclic, intermittent-constant, causing a complex set of responses from the periodontium (see "Biomechanics of the periodontium").

Thus, the statics of a bridge with two-sided, symmetrically located supports is considered as a beam lying freely on rigid "bases". With a force K applied to the beam in the center, the latter bends by some amount S. At the same time, the supports remain stable (Fig. 103).

A fixed dental bridge with bilateral, symmetrically located supports should be considered as a beam rigidly fixed on an elastic base (Fig. 104).

The load K, applied in the center of the intermediate part (body) of the bridge, is evenly distributed between the supports.

K=P1+P2; R1R2

The force K, when applied to the body of a bridge, causes a moment of rotation (M), which is equal to the product of the magnitude of the force K and the length of the shoulder (a or b). Since, when the force K is applied in the center of the body of the bridge, the arms a and are parallel, then the two moments of rotation - Ka and K "b, having opposite signs, are balanced.

If the force K moves towards one of the supports (Fig. 105), then the moment of rotation and the load in the area of ​​\u200b\u200bthis support increase, and at the opposite one they decrease (shoulder a<б).

The load on the supporting tooth is always proportional to the distance of the support from the place of application of the force.

Provided that the masticatory pressure realized in the force K coincides with the functional (physiological) axis of one of the supporting teeth, then this tooth bears the full load, and in the second support the force K will be of the opposite sign.

The supports move under load - they sink deep into the dental alveolus (toward the bottom of the alveolus) until equal but oppositely directed forces from the periodontal fibers arise. A biostatic balance of forces is established - the applied force and the elastic deformation of the periodontal fibers and bone tissue. This relationship can be determined statically by two counteracting moments of the “bridge-periodontium” system directed against each other. After the load is removed, the supports return to their original position. As a result, they make a path equal to the values ​​of nPBx

Under the action of a vertical load and a load at an angle during lateral movements of the lower jaw, deflection S and torque occur in the body of the bridge. As a result, the supports experience a tilting moment by the value< а. На внутренней стороне опор волокна периодонта сжимаются (+), на наружной — растягиваются (—), находясь в уравновешенном состоянии (см. рис. 105). Степень отклонения опор от исходного состояния (величина а) зависит от параметров тела мостовидного протеза, выраженности бугорков на окклюзионной поверхности, величины перекрытия тела мостовидного протеза в области передних зубов.

The main provisions of statics given in relation to the dental bridge dictate the need to systematize the types of bridges depending on the location of the supports, their number and the shape of the intermediate part.

Rice. 106. Types of bridge-like non-removable dentures, depending on the location and number of supports. Explanation in the text.

So, depending on the location of the supports and their number, it is necessary to distinguish 5 types of bridges: 1) a bridge with a bilateral support (Fig. 106, a); 2) with an intermediate additional support (Fig. 106, b); 3) with double (medial or distal) support (Fig. 106, c); 4) with paired double-sided supports (Fig. 106, d); 5) with a one-sided console (Fig. 106, e).

The shape of the dental arch is different in the anterior and lateral areas, which naturally affects the intermediate part of the bridge. So, when replacing the front teeth, the intermediate part is arched, when replacing the chewing teeth, it approaches a rectilinear shape (Fig. 107, a, b). With a combination of defects in the dentition in the anterior and lateral sections and replacing them with one bridge prosthesis, the intermediate part has a combined shape (Fig. 107, c, d).

The presence of a cantilever element in the design of a bridge prosthesis, an arched or rectilinear body of a bridge prosthesis, a different direction of the axes of the supporting teeth due to their anatomical location in the dentition significantly affect biostatics and should be taken into account when justifying treatment with bridge prostheses.

Rice. 107. Types of bridge-like non-removable dentures depending on the shape of the intermediate part (body). Explanation in the text.

Rice. 108. Statics of the biomechanical system "bridge fixed denture - periodontium" with a cantilever element (indicated by an arrow). Explanation in the text.

In particular, when turning on the cantilever element, it is necessary to take into account the length of the lever that counteracts the lever of the applied force (see Fig. 106).

It is generally accepted that the longer the arm e (M1 \u003d P1. e) compared with the shoulder c (M2 \u003d K "c), the more it counteracts the eccentric load K on the console. In the state of equilibrium, the moment of rotation of the lever e acts against the moment of the lever c , i.e. Mi>M2 (Fig. 108) When the opposite lever is shortened, the fulcrum near the console is loaded under pressure, becomes a point of rotation, and the remote fulcrum experiences "stretching", "dislocation" - a moment of rotation with a negative sign.

With an arcuate body of a bridge prosthesis, the applied force K always acts in an eccentric vertical direction relative to the axes of the supports (canines, premolars). The larger the radius of the arc, the greater the negative effect of the moment of rotation on the supports (Fig. 109, a).

The moment of rotation is expressed as M = K-a, where a is a segment of the perpendicular to the transversal line connecting the supports to each other. Under the action of force K, it becomes the axis of rotation, the moment of "overturning" of the supports. To neutralize this negative component, Schroeder points out the need to include chewing teeth in the support of a bridge with an arcuate body with the formation of the same length of counteraction levers (Fig. 109, b), bilateral power blocks of teeth. The moment of rotation must be compensated by them.

Rice. 109. Statics of the biomechanical system "bridge fixed prosthesis - periodontium" with an arched shape of the body of the prosthesis. a - double-sided single support; b — bilateral multiple support.

With a rectilinear shape of the body of the bridge prosthesis in the region of the lateral teeth, the vertical (centric or eccentric) chewing pressure is perceived by the complex relief of the chewing surface, where the slopes of the tubercles are inclined planes (Fig. PO). The force K, according to the wedge law, is decomposed into two components, of which the forces K (perpendicular to the axis) and the resulting forces Kr cause a moment of rotation. The latter, which is not compensated by anything, leads to vestibular-oral deviations of the supporting teeth (Fig. 111).

In a state of biostatic equilibrium, the moments of rotation are equal to each other М1 = М2; their value does not exceed the value of elastic deformation of periodontal fibers. To maintain this balance, it is necessary to create the same type of slopes of the vestibular and lingual (palatine) tubercles when modeling the chewing surface. As a compensation for the negative effect of the moment of rotation, one can consider the connection of additional supports lying in a different plane, in particular, canines or third molars.

The possibility of treatment with bridges, the application of additional masticatory load is based on the general biological position about the presence of physiological reserves in human tissues and organs. This allowed V. Yu. Kurlyandsky to put forward the concept of "reserve forces of the periodontium." It finds confirmation in the analysis of an objective study of periodontal pressure endurance - gnathodynamometry. The endurance limit of the periodontium to pressure is threshold loads, the increase of which leads to pain, for example, for premolars - 25-30 kg, molars - 40-60 kg. However, under natural conditions, when biting and chewing food, a person does not develop efforts until pain occurs.

Consequently, part of the periodontal endurance to the load is constantly realized in natural conditions, and part is a physiological reserve, realized under extreme conditions, in particular during illness.

It is accepted theoretically, tentatively, to consider that out of 100% of the functional capabilities of an organ, 50% is normally spent, and 50% is a reserve. This is the main theoretical basis in the clinic for the selection and justification of the number of supporting teeth for a dental bridge and its structural elements, as well as systems for fixing removable dentures.

The load on the periodontium of the supporting teeth, its magnitude and direction are directly dependent on the state of the periodontal teeth-antagonists. Under natural conditions, the size of the food bolus between the teeth does not exceed the length of three teeth. Therefore, we can assume that the maximum load, for example, in the area of ​​chewing teeth is possible from the total endurance of the second premolar and two molars (7.75-50% of which is 3.9); in the area of ​​the anterior teeth - two central and two lateral incisors (4.5-2.25-50%).

Since the increase in chewing pressure will primarily determine the reaction of single-standing antagonist teeth, the contractile force of the chewing muscles will be regulated precisely through the periodontal muscle reflex of the latter. If the antagonist is a bridge, then the magnitude of the impact from it is the total value of the periodontal endurance of all supporting teeth. Let us consider specific clinical situations when deciding on a reasonable choice of a method of treatment with bridges.

The patient does not have