Anomalies and deformities of the jaws

The size and shape of the jaws can vary significantly in accordance with the individual size and shape of the entire face. Deformation of one or both jaws can only be discussed in the case of a sharp deviation from the conventional average values that most closely correspond to the remaining parts of the face of a given individual.

The second criterion for the presence of jaw deformation is a violation of chewing function and speech.

Excessive development of the lower jaw is usually called progenia or macrogenia, and underdevelopment is called microgenia or retrognathia.

Excessive development of the upper jaw is called macrognathia or prognathia, and underdevelopment is called micrognathia or opisthognathia.

[ 1 ], [ 2 ], [ 3 ]

What causes jaw abnormalities and deformities?

The causes of dental, maxillofacial and facial deformities are very diverse. Thus, organo- and morphogenesis of the jaws in the fetus may be disrupted under the influence of hereditary effects on the embryo, diseases suffered by the parents (including endocrine and metabolic disorders in the mother's body, infectious diseases ), radiation exposure, as well as due to physiological and anatomical disorders of the mother's genitals and abnormal position of the fetus.

In early childhood, jaw development may be disrupted by endogenous factors (heredity, endocrine disorders, various infectious diseases, metabolic disorders) and exogenous influences (inflammation in the growth zones of the jaws, trauma, including birth trauma, radiation damage, mechanical pressure, bad habits - sucking a finger, pacifiers, lower lip or putting a fist under the cheek during sleep, pushing the lower jaw forward during the period of wisdom teeth eruption, while playing the children's violin, etc., dysfunction of the masticatory apparatus, disruption of the act of swallowing, nasal breathing, etc.).

In childhood and adolescence, as well as in adults, jaw deformations may occur under the influence of accidental trauma, gross cicatricial contractions, surgical intervention and pathological processes (osteomyelitis, ankylosis, noma, etc.). The latter can lead to excessive bone regeneration or, conversely, to resorption and its atrophy.

The dystrophic process can lead to half, or bilateral, or limited atrophy of the soft tissues and skeleton of the face (for example, the so-called hemiatrophy).

In the presence of conditions that promote hypertrophy of the facial bones, acromegalic proliferation is observed, especially in the lower jaw.

Quite common causes of acquired unilateral underdevelopment of the lower jaw are osteomyelitis, purulent inflammation of the temporomandibular joint and mechanical damage to the condylar process in the first decade of the patient's life.

Pathogenesis of jaw anomalies and deformations

The underlying pathogenetic mechanisms of jaw deformation development are the suppression or partial shutdown of jaw growth zones, bone loss, and shutdown of the chewing or mouth opening functions. In particular, the main factor in the development of unilateral microgenia is the disruption of the lengthwise growth of the lower jaw due to congenital or osteomyelitic lesions or shutdown of growth zones, especially those located in the area of the head of the lower jaw.

Endocrine disorders in a growing organism play a significant role in the pathogenesis of jaw deformations.

The pathogenesis of combined deformations of facial bones is closely related to the dysfunction of the skull base synchondroses. Micro- and macrognathia are caused by either inhibition or irritation of the growth zones localized in the heads of the mandibular bone.

In the development of progenia, the pressure of the incorrectly positioned tongue and the reduction in the volume of the oral cavity play an important role.

Symptoms of jaw anomalies and deformations

Among the symptoms of jaw deformations, the first place usually occupies the patient's (and often the people around him) dissatisfaction with the appearance of the face. Young men and women express this complaint especially persistently: they ask to eliminate the "disfigurement" of their face.

The second symptom is a violation of one or another function of the dental-maxillofacial apparatus (chewing, speech, the ability to sing, play a wind instrument, smile broadly, laugh cheerfully and cheerfully with friends, with family, at work).

Malocclusion makes it difficult to chew food, forcing you to swallow it quickly, without processing it with saliva. Some solid foods are completely unavailable. Eating in a canteen, restaurant or cafe is simply impossible, since the sight of sick people causes disgust in those around you.

Complaints may also include discomfort (in the stomach area) after eating, which is explained by the consumption of coarse, unchewed food.

Alienation in the family and at work forces patients to self-isolate in relation to the work collective, family, and gives rise to mental instability.

Some patients (especially those suffering from microtenia) complain of very loud snoring (while sleeping on their back): "As if I were starting a motorcycle or a truck all night long" - this is how one of our patients put it. This excludes the possibility of sleeping together with a wife (husband) and sometimes serves as a reason for divorce; this, in turn, aggravates psychoemotional instability, and sometimes - attempts at suicide. In short, this category of patients is very difficult and requires especially strict adherence to all the rules of deontology, careful sedative preoperative premedication, thoughtful selection of anesthesia during and after surgery.

With anomalies and deformations of the jaws, sharp changes in the dental system are often observed (dental caries, enamel hypoplasia, pathological abrasion, abnormal position of teeth, changes in periodontal tissues and dysfunction of the masticatory apparatus).

The frequency of lesions and the clinical picture of their manifestation are different. In particular, the incidence of caries in such patients is observed 2-3 times more often than in patients without bite disorders. The intensity of caries lesions in the deformation of the upper jaw after cheiloplasty and uranoplasty (in all age groups) is significantly higher than in the prognathism of the lower jaw and open bite.

Inflammatory-dystrophic changes in the periodontium are observed in most patients. In case of prognathism of the lower jaw and open bite, limited catarrhal gingivitis is detected near the teeth that were not in contact with the antagonists.

The structure of the periodontal bone tissue is characterized by chaos and blurring of the bone pattern with predominant damage to the lower jaw.

Deformations of the upper jaw are characterized by pathological gingival pockets, diffuse hypertrophic gingivitis, most often in the area of the front teeth located along the edges of the cleft, and teeth that experience the greatest load.

Disorders of the masticatory function (according to masticationograms) are manifested by grinding and mixed types of chewing.

The electrical excitability of the pulp of teeth under conditions of overload and underload, as well as in non-functioning teeth, decreases.

To obtain a complete picture of local status disorders, it is necessary to use such research methods as linear and angular measurements of the contour of the entire face and its parts; making photographs (in profile and full face) and plaster masks; electromyographic assessment of the masticatory and facial muscles; radiographic examination of the facial bones and cranium (teleradiography according to Schwarz, orthopantography, tomography). All these data allow not only to clarify the diagnosis, but also to choose the most appropriate surgical option.