Malocclusion

An incorrect bite is an anomaly of the dentoalveolar system of a person. Anomaly is expressed in violations of the position of the dentition in relation to each other and in the defects of the upper and lower teeth closing both at rest (with the mouth closed) and during the movement of the jaws (during meals and conversation).

Incorrect bite of the teeth is formed for various reasons, but with the help of modern orthodontic methods in some cases can be corrected.

[1], [2], [3], [4]

The causes of malocclusion

To date, in orthodontics, which deals with tooth-jaw problems, the key cause of malocclusion is recognized as congenital, that is, genetically determined abnormalities in the anatomical location of the jaw bones of the skull and dentition. In childhood - as the bones grow, during the eruption of the milk teeth and their constant changes - the inherited proportions of the upper and lower jaws, the height of the gums and the arrangement of the teeth are formed. In addition, affect the formation of bite and soft tissue (cheeks, lips and tongue).

But the main thing, experts emphasize, is not the arrangement of teeth, but the ratio of the dentition to other craniofacial structures. Thus, when one of the jaws extends beyond a given imaginary line in the coronal plane of the skull, it is a question of prognathism (with the Greek pro - forward, gnathos - jaw), in which the upper and lower teeth do not coincide properly, that is, there is an incorrect occlusion teeth.

A disposition of the teeth causes a violation of the normal bite in the case of a significant curvature of the teeth (which disrupts the harmony of the tooth row and the closing of the teeth), when the teeth rotate relative to their own axis (so called "bored teeth"), when their size is abnormally large, and when the teeth grow in an unauthorized place or in an excess quantity (and this happens!).

Very often an incorrect bite in a child is formed due to a violation of nasal breathing associated with chronic forms of such diseases as allergic or vasomotor rhinitis, sinusitis, adenoiditis; as well as hypertrophy of pharyngeal tonsils (glands) or curvature of the nasal septum. The inability to breathe normally leads to the fact that the child constantly opens his mouth during sleep. What happens in this case? There is a long nonphysiological strain of the maxillofacial, chin-hyoid and anterior part of the digastric muscles, lowering the lower jaw. Stressed muscles (while they need to be relaxed) stretch forward the skeletal structures of the facial part of the skull, in the first place, the upper jaw.

To factors contributing to the formation of a malocclusion in children, dentists refer to the lack of natural feeding (breast sucking requires certain efforts of the baby and strengthens his maxillofacial muscles), too long using a pacifier, sucking fingers, as well as later erupting and changing dairy incisors .

In addition to hereditary features of the structure of the skull and facial structures, an incorrect bite in adults can begin to form at a later age as a change in the natural line of the gingival margin - with secondary deformation of the dentition. This is due to the loss of individual teeth and the displacement of the remaining teeth forward or backward. And also with inflammation of the retaining tooth in the alveolus of periodontal and atrophic processes in the jaw bone.

In some cases, adults may develop an incorrect bite after prosthetics: if the jaw position is normal and the temporomandibular joint is overloaded because of the incompatibility of the manufactured prostheses with the individual anatomical features of the dental jaw system of the patient.

Types of malocclusion and their symptoms

Before considering the types of malocclusion, it is appropriate to characterize the main signs of a correct (or orthognathic) occlusion, which is considered ideal and, as doctors say, is infrequent.

Closure of teeth (occlusion) is considered absolutely correct when:

• The imaginary vertical line passing between the upper central incisors is a continuation of the same line between the lower central incisors;
• an arcuate row of teeth crowns of the upper jaw (upper dental arch) not more than a third overlaps the crowns of the teeth of the lower jaw;
• the lower incisors relatively to the upper ones are slightly shifted backward (into the oral cavity), and the upper incisors slightly protruding anteriorly;
• between the front teeth of the upper and lower jaws there is a cutting-tubercular contact, that is, the cutting edge of the lower anterior teeth is in contact with the palatal tubercles of the upper incisors;
• the upper teeth are located with the slope of the crowns to the outside, and the crowns of the lower teeth are inclined towards the oral cavity;
• the lower and upper molars close together, and each molar with chewing surfaces comes into contact with two opposing teeth;
• between the teeth there are no gaps.

And now - the types of malocclusion, among which orthodontists distinguish: distal, mesial, deep, open and cross bite.

The distal bite (or maxillary prognathism) is easily recognized by the upper teeth, which are too advanced, and a somewhat "lowered" lower row of teeth in the mouth. This structure of the dentoalveolar system is a manifestation of hypertrophied upper jaw or insufficient development of the lower one. In humans, the external symptoms of an incorrect bite of this species are a shortened lower third of the face, a small chin and a slightly protruding upper lip.

With mesial occlusion, the opposite is true: the lower jaw overgrows the upper jaw and extends forward along with the chin (to varying degrees, from a little unnoticeable to the so-called "Habsburg jaw", which this monarchical dynasty differed). This bite is also called mandibular or mandibular prognathism, as well as retrognathism.

For a deep bite (deep incisive dizoklyuzii) is characterized by a significant overlapping of the crowns of the incisors of the lower jaw with the upper front teeth - half or more. It should be noted that the external symptoms of an incorrect bite of such a modification may have the form of a reduction in the size of the facial region of the head (from the chin to the hair growth line), and also slightly thickened, as if turned outward, the lower lip.

Incorrect bite in adults can be open: from other species it is distinguished by the absence of the closing of several or most molars of both dental rows, in which crevices gap between their chewing surfaces. If a person's mouth is always slightly open, then one can almost confidently say that he has an open, incorrect bite of the jaw.

But with a cross bite (vestibulocclusion), the underdevelopment of the jaw is noted on the one hand, but in this case the violation of the contact of the chewing surfaces of the molars can be either unilateral or bilateral. A typical external appearance of this bite is the asymmetry of the face.

Also, many orthodontists distinguish the wrong bite in the form of alveolar prognathism (dental alveolar shape of the distal occlusion), in which not the entire jaw protrudes, but only the alveolar process of the jaw, where the alveoli of the teeth are located.

Consequences of malocclusion

The consequences of a malocclusion, in the first place, are expressed in the fact that the process of chewing food - especially with an open bite - can be difficult, and in many, the degree of grinding food in the mouth does not correspond to the consistency that ensures normal digestion. Negative outcome - problems with the gastrointestinal tract.

What is the danger of an incorrect bite other than this? Possible consequences of distal occlusion: the chewing load on the teeth is distributed unevenly, and a significant part of it falls on the back teeth, which will quickly wear off and deteriorate.

The most common consequence of deep bite is the increased wear of hard dental tissues. It, in turn, leads to a decrease in the height of the occlusion. Reduction of the bite "drags" behind itself the overstrain of the masticatory muscles, which ultimately affects the state of the temporomandibular joints: they crackle, crack and sometimes hurt. And when squeezing nerve fibers, neuralgia may develop.

Also, traumatization of soft tissues of the mouth, gums, and tongue increases; can be distorted articulation and diction, difficulty breathing or swallowing.

What else does the wrong bite affect? For example, on prosthetics with an incorrect bite, which can be simply impossible because of the existing problems with the closing of the teeth and the structure of the jaw. So the dentist-prosthetist will certainly send the patient with significant malocclusion to the orthodontist.

By the way, for the same reason - that is, with anomalies of the dentoalveolar system - implants with incorrect bite to put also very problematic. However, if the degree of prognathism is negligible, then there may not be any obstacles for dental implantation.

And a strongly pronounced wrong bite and army, in particular, service in the Airborne Forces or in the submarine fleet are incompatible concepts.

[5], [6], [7], [8]

How to determine the wrong bite?

The main characteristic features have been described above - see the section Types of malocclusion and their symptoms, but only the orthodontist can determine the exact type of malocclusion .

In clinical orthodontics, as well as maxillofacial surgery, the incorrect bite of the jaw is confirmed on the basis of symmetry data (studying the shape of the dentition); with the help of electromotonometry (determination of the tonus of the jaw muscles); MRI of the temporomandibular joint.

Assessment of the relative location of the jaws with respect to all the skull bone structures is performed by X-ray and 3D 3D cephalometry. Clinical determinants also include analysis of the proportions of the face (the size of the nasolabial angle, the ratio of the distance from the chin to the nose, the relationship between the upper and lower lip), the angle of the occlusal plane of the teeth, and so on.

Treatment of malocclusion

In the case of problems with the dentoalveolar system, it would be more accurate to name their solution - correcting an incorrect bite.

So, what if the wrong bite is a serious problem not only in the appearance of the person, but also in the performance of the main function of the teeth - chewing? You need to contact an orthodontist. However, it should be borne in mind that they are able to adjust the location of individual teeth or the entire dentition, but it is impossible to change the anomalies of the jaw bone structure in most cases.

These or other bite disorders are common to many people, but they do not see any special need for treating this pathology to improve external data. For example, universally recognized stars with an incorrect bite hardly thought about it and achieved success. To begin with, both the judges of the 67th Cannes Film Festival and members of the European Film Academy recognized Timothy Spall as the best actor of the Old World in 2014 for the brilliant performance of the English painter William Turner in the tape "Mr. Turner". On the account of this remarkable artist with a wrong bite - fifty movies.

Although many stars with an incorrect bite wore orthodontic devices - to straighten out crooked teeth and have the notorious Hollywood smile (Brigitte Bardot, Cameron Diaz, Tom Cruise, etc.). But among those whose talent is recognized and appreciated despite obvious signs of a malocclusion, there are many nice names: Louis de Funes, Freddie Mercury, Alice Freindlich, Arnold Schwarzenegger, Quentin Tarantino, Orlando Bloom, Melanie Griffith, Reese Witherspoon, Sigourney Weaver ...

Let's go back to the methods of treating an incorrect bite. The most famous and common of these is the installation of bracket systems.

Braces with wrong bite

Braces are a non-removable orthodontic design that facilitates the alignment of the teeth and correcting the malocclusion, because the dental arches are shifted by constant pressure (the strength and direction of which the orthodontist precisely calculates).

Bracket-systems are made of metal, plastic, ceramics, etc. In the place of attachment to the crowns of the teeth, they are divided into vestibular (set on the face of the teeth) and lingual (fixed on the inner surface of the teeth). The process of equalizing the teeth is provided by special power arcs fixed in the grooves of the brackets. The active process lasts from one to three years and requires systematic medical supervision.

The final - the retentive - the stage of correcting the malocclusion with the help of braces should consolidate the result obtained in aligning the dentition. This stage can last several years; it consists in the wearing of removable or non-removable orthodontic retentive plates with metal or plastic arcs that are fixed on the inner surface of the teeth. Other orthodontic devices are also used.

According to experts, braces are most effective in alveolar prognathism. However, it is possible that the incorrect bite after braces may return with insufficient retention or incorrect calculation and installation of the orthodontic design.

Braces with an incorrect bite, in particular, when distal, are most often installed after the removal of two teeth of the upper dentition - to reduce its size. To do without dental extraction, adolescent patients are treated with special correctors for the distal occlusion: Twin Fjrce, Herbst, Forsus, Subbach's spring (SUS). The principle of their action is based on the shifting downward and upward condylar processes in the joint fossa of the temporomandibular joint, as a result of which the level of extension of the mandible is corrected forward.

Braces with an incorrect bite in children can be established only after the completion of the change of milk teeth constant. For adults, there is no age limit. However, breket-systems are not put at cardiovascular pathologies in the stage of decompensation; autoimmune diseases, osteoporosis, thyroid pathologies, diabetes, tuberculosis, malignant tumors, venereal diseases and HIV.

[9], [10], [11]

Correction of an incorrect occlusion: kapy, veneers, bite plates, screws

Orthodontic kapy - removable polyurethane lining for teeth - designed to align the dentition. Kapy should be done individually, according to the calculations of an orthodontist, only in this case they will work at the expense of tight fitting of teeth and pressure in the right direction. Every two months, the caps should be changed to new ones - in accordance with the changed position of the teeth. However, neither the distal, nor the mesial, nor the deep bite of the cap can be corrected.

Veneers with an incorrect bite are also of little use, since their purpose is the restoration of the front teeth, and not the correction of the occlusion. Although dentists argue that the veneers will help "hide minor bite defects, including crooked teeth." But there is a significant difference between "hide" and "fix". In addition, composite veneers are not particularly strong, and ceramic veneers are very expensive. And in both cases it is necessary to grind the enamel from the teeth.

But biting palatine plates - what you need with this kind of wrong bite in children, like a deep bite. This design can be removable (to stabilize the corrected bite, put on for the night and for part of the day) and non-removable (repositioning tires for correcting deep bite). The correcting plate is placed on the teeth with the aid of a clamping fixture; The plate presses on the teeth and thereby contributes to their predetermined offset.

Crossing the wrong jaw bite is a difficult task for orthodontists, to solve which you need to expand the dental arch of the upper jaw, move some teeth, and then stabilize the position of the dentition. For this purpose, the use of orthodontic devices and screws acting on a mechanical principle: the Engle or Ainsworth apparatus, the Coffin spring apparatus, the Hausser spring screw, the Philip's clasp screw, the expanding Planas screw, the Müller arc screw, and so on.

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Surgical treatment of malocclusion

Surgical correction of an incorrect occlusion can be carried out with a pronounced pathology of the dentoalveolar system associated with abnormalities in the anatomical location of the jaw bones of the skull and dentition. For example, maxillofacial surgeons can remove part of the bone of the lower jaw, or increase it to an acceptable size by directional bone regeneration.

But most often the scalpel is used by surgical orthodontists to increase the effectiveness of orthodontic devices, before the installation of which can be performed corticotomy (compactotestomy) - puncturing the gingival tissue in the area above the tips of the dental roots. This is done in order to activate intracellular metabolism in the bone tissue of the dental hole and accelerate the process of correcting the occlusion in patients.