Improper bite

Malocclusion is an anomaly of the human dental system. The anomaly is expressed in the disturbances of the position of the dental arches in relation to each other and in defects in the closure of the upper and lower teeth both at rest (with the mouth closed) and during jaw movement (during eating and talking).

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

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

Causes of malocclusion

Today, in orthodontics, which deals with dental and jaw problems, the key cause of malocclusion is recognized as congenital, that is, genetically determined deviations in the anatomical arrangement of the jaw bones of the skull and dental arches. In childhood - as the bones grow, during the eruption of baby teeth and their replacement by permanent ones - inherited proportions of the upper and lower jaws, the height of the gums and the arrangement of the teeth are formed. In addition, soft tissues (cheeks, lips and tongue) also influence the formation of the bite.

But the main thing, as experts emphasize, is not the arrangement of the teeth, but the relationship of the dental row with other craniofacial structures. Thus, when one of the jaws protrudes beyond the given imaginary line in the coronal plane of the skull, we are talking about prognathism (from the Greek pro - forward, gnathos - jaw), in which the upper and lower teeth do not match properly, that is, there is an incorrect bite of the teeth.

And the arrangement of teeth becomes the cause of a violation of the normal bite in the case of significant curvature of the teeth (which disrupts the order of the dental row and the closure of the teeth), when the teeth rotate relative to their own axis (the so-called "crowded teeth"), when they are abnormally large, and also when teeth grow in the wrong place or in excess of the norm (and this happens!).

Very often, malocclusion 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 the pharyngeal tonsils (glands) or curvature of the nasal septum. The inability to breathe normally through the nose leads to the child's mouth being constantly open during sleep. What happens in this case? There is a long-term non-physiological tension of the mylohyoid, geniohyoid and anterior part of the digastric muscles, which lower the lower jaw. The tense state of the muscles (while they should be relaxed) pulls forward the skeletal structures of the facial part of the skull, primarily the upper jaw.

Dentists attribute the following factors to the development of malocclusion in children: lack of natural feeding (breastfeeding requires a certain amount of effort from the baby and strengthens his jaw and facial muscles), using a pacifier for too long, sucking fingers, as well as late eruption and replacement of milk incisors.

In addition to hereditary features of the structure of the skull and facial structures, malocclusion in adults can begin to form at a later age in the form of a change in the natural line of the gum margin - with secondary deformation of the dentition. This occurs due to the loss of individual teeth and the displacement of the remaining teeth forward or backward. And also with inflammation of the periodontium holding the tooth in the alveolus and atrophic processes in the bone tissue of the jaw.

In some cases, adults may develop malocclusion after prosthetics: when the normal position of the jaws is disrupted and the temporomandibular joint is overloaded due to the discrepancy between the manufactured prostheses and the individual anatomical features of the patient’s dental system.

Types of malocclusion and their symptoms

Before considering the types of malocclusion, it is appropriate to characterize the main features of a correct (or orthognathic) bite, which is considered ideal and, according to doctors, is rare.

The occlusion of teeth 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;
• the arched row of crowns of the teeth of the upper jaw (upper dental arch) overlaps the crowns of the teeth of the lower jaw by no more than a third;
• the lower incisors are slightly displaced backwards (into the oral cavity) relative to the upper ones, and the upper incisors are slightly pushed forward;
• between the front teeth of the upper and lower jaws there is an incisal-tubercular contact, that is, the incisal edge of the lower front teeth comes into contact with the palatine tubercles of the upper incisors;
• the upper teeth are positioned with the crowns tilted outward, and the crowns of the lower teeth are tilted towards the oral cavity;
• the lower and upper molars come together, and each molar's chewing surfaces touch the two opposite teeth;
• There are no spaces between the teeth.

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

Distal bite (or maxillary prognathism) is easily recognized by the upper teeth that are too far forward and the lower row of teeth that is somewhat “pushed back” into the mouth. This structure of the dental system is a manifestation of a hypertrophied upper jaw or insufficient development of the lower jaw. In humans, the external symptoms of this type of malocclusion are a shortened lower third of the face, a small chin, and a slightly protruding upper lip.

With a mesial bite, everything is the other way around: the lower jaw outgrows the upper jaw and moves forward together with the chin (to varying degrees - from barely noticeable to the so-called "Habsburg jaw", which distinguished this monarchical dynasty). This bite is also called mandibular or mandibular prognathism, as well as retrognathism.

A deep bite (deep incisor malocclusion) is characterized by a significant overlap of the crowns of the lower jaw incisors by the upper front teeth - by half or more. It should be noted that the external symptoms of such a modification of malocclusion may be a decrease in the size of the facial area of the head (from the chin to the hairline), as well as a slightly thickened, as if turned outward, lower lip.

Malocclusion in adults can be open: it differs from other types by the absence of closure of several or most of the molars of both dental arches, with gaps between their chewing surfaces. If a person's mouth is constantly slightly open, then it is almost certain that he has an open malocclusion of the jaw.

But with a cross bite (vestibuloocclusion), underdevelopment of the jaw is noted on one side, but at the same time, the violation of the contact of the chewing surfaces of the molars can be either unilateral or bilateral. The typical external appearance of such a bite is facial asymmetry.

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

Consequences of malocclusion

The consequences of malocclusion are primarily expressed in the fact that the process of chewing food - especially with an open bite - can be difficult, and for many, the degree of grinding of food in the oral cavity does not correspond to the consistency that ensures normal digestion. The negative result is problems with the gastrointestinal tract.

What else does malocclusion threaten? 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 wear out and deteriorate faster.

The most common consequence of a deep bite is increased wear of hard dental tissues. This, in turn, leads to a decrease in the bite height. A decrease in bite "pulls" overstrain of the masticatory muscles, which ultimately affects the condition of the temporomandibular joints: they crunch, click and sometimes hurt. And when nerve fibers are compressed, neuralgia can develop.

There is also increased trauma to the soft tissues of the oral cavity, gums, and tongue; articulation and diction may be distorted, breathing or swallowing may be difficult.

What else does malocclusion affect? For example, prosthetics for malocclusion, which may simply be impossible due to existing problems with the closure of teeth and the structure of the jaw. So a dental prosthetist will certainly refer a patient with significant malocclusion to an orthodontist.

By the way, for the same reason - that is, with anomalies of the dental system - it is also very problematic to install implants with an incorrect bite. However, if the degree of prognathism is insignificant, then there may be no obstacles to dental implantation.

Moreover, a severely pronounced malocclusion and the army, in particular service in the Airborne Forces or in the submarine fleet, are incompatible concepts.

[ 5 ], [ 6 ]

How to identify malocclusion?

The main characteristic signs were described above - see the section Types of malocclusion and their symptoms, but only an orthodontist can accurately determine the type of malocclusion.

In clinical orthodontics, as well as maxillofacial surgery, malocclusion of the jaw is confirmed on the basis of symmetroscopy data (study of the shape of the dental arches); using electromyotonometry (determination of the tone of the jaw muscles); MRI of the temporomandibular joint.

The assessment of the relative position of the jaws relative to all the bone structures of the skull is carried out using fluoroscopy and computer 3D cephalometry. Clinical determinants also include an analysis of facial proportions (the size of the nasolabial angle, the ratio of the distance from the chin to the nose, the relationship between the upper and lower lips), determination of the angle of the plane of occlusion of the teeth, etc.

Treatment of malocclusion

In case of problems with the dental system, it would be more accurate to call their solution - correction of malocclusion.

So, what to do if malocclusion is a serious problem not only in a person’s appearance, but also in the performance of the main function of the teeth – chewing? You need to contact orthodontists. However, it should be borne in mind that they can correct the position of individual teeth or the entire dental row, but in most cases it is impossible to change the anomalies of the jaw bone structure.

Many people have one or another bite disorder, but they do not see any particular need to treat this pathology to improve their appearance. For example, recognized stars with an incorrect bite hardly thought about it and achieved success. Let's start with the fact that both the jury of the 67th Cannes Film Festival and members of the European Film Academy recognized the 57-year-old Briton Timothy Spall as the best actor of the Old World in 2014 - for his brilliant performance as the English painter William Turner in the film "Mr. Turner". This remarkable actor with an incorrect bite has fifty film roles to his credit.

Although many stars with malocclusion wore orthodontic devices - to straighten 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 malocclusion, we can name many famous names: Louis de Funes, Freddie Mercury, Alisa Freundlich, Arnold Schwarzenegger, Quentin Tarantino, Orlando Bloom, Melanie Griffith, Reese Witherspoon, Sigourney Weaver...

Let's get back to the methods of treating malocclusion. The most famous and widespread of them is the installation of braces.

Braces for malocclusion

Braces are a non-removable orthodontic device that helps align teeth and correct malocclusions by moving the dental arches through constant pressure (the strength and direction of which is precisely calculated by the orthodontist).

Bracket systems are made of metal, plastic, ceramics, etc. According to the place of attachment to the crowns of the teeth, they are divided into vestibular (installed on the front surface of the teeth) and lingual (fixed on the inner surface of the teeth). The process of teeth alignment 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 monitoring.

The final - retention - stage of correcting malocclusion with braces should consolidate the obtained result of aligning the dental row. This stage can last several years; it consists of wearing removable or non-removable orthodontic retention plates with metal or plastic arches 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 malocclusion after braces may return due to insufficient retention or incorrect calculation and installation of the orthodontic structure.

Braces for malocclusion, in particular, for distal, are most often installed after the removal of two teeth of the upper dental row - to reduce its size. To avoid dental extraction, adolescent patients use special correctors of distal occlusion: Twin Fjrce, Herbst, Forsus, Sabbah spring (SUS). The principle of their action is based on the downward and upward displacement of the condylar processes in the glenoid fossa of the temporomandibular joint, as a result of which the level of forward protrusion of the lower jaw is corrected.

Braces for malocclusion in children can be installed only after the replacement of baby teeth with permanent ones. There are no age restrictions for adults. However, braces are not installed in cases of cardiovascular pathologies in the decompensation stage; autoimmune diseases, osteoporosis, thyroid pathologies, diabetes, tuberculosis, malignant tumors, venereal diseases and HIV.

[ 7 ], [ 8 ], [ 9 ]

Correction of malocclusion: caps, veneers, bite plates, screws

Orthodontic mouth guards are removable polyurethane pads on the teeth, designed to align the dentition. Mouth guards should be made individually, according to the calculations of an orthodontist, only in this case will they work due to the tight "fit" of the teeth and pressure in the right direction. Every two months, the mouth guards should be changed to new ones - in accordance with the changed position of the teeth. However, neither distal, nor mesial, nor deep bite can be corrected by mouth guards.

Veneers are also of little use for malocclusion, since their purpose is to restore the front teeth, not correct the bite. Although dentists claim that veneers will help "hide minor bite defects, including crooked teeth." But there is a significant difference between "hide" and "correct." In addition, composite veneers are not particularly durable, and ceramic veneers are expensive. And in both cases, you will have to grind down the enamel from your teeth.

But bite palatal plates are what is needed for such a type of malocclusion in children as a deep bite. This design can be removable (to stabilize the corrected bite, put on at night and for part of the day) and non-removable (repositioning splints for correcting a deep bite). The corrective plate is installed on the teeth using a clasp fastening; the plate presses on the teeth and thus contributes to their specified displacement.

Crossbite of the jaw is a complex task for orthodontists, which requires widening the dental arch of the upper jaw, moving some teeth, and then stabilizing the position of the dental row. For this purpose, orthodontic devices and screws that operate on a mechanical principle are used: Angle or Ainsworth devices, a device with a Coffin spring, Hausser spring screw, Philippe clasp screw, Planas expansion screw, Muller arc screw, etc.

[ 10 ]

Surgical treatment of malocclusion

Surgical correction of malocclusion can be performed in cases of severe pathology of the dental system associated with deviations in the anatomical arrangement of the jaw bones of the skull and dental arches. For example, maxillofacial surgeons can remove part of the lower jaw bone or build it up to an acceptable size by means of directed bone regeneration.

But most often, orthodontic surgeons resort to the help of a scalpel to increase the effectiveness of orthodontic devices, before the installation of which a corticotomy (compactoosteotomy) can be performed - puncturing the bone tissue of the gum in the area above the tops of the tooth roots. This is done in order to activate intracellular metabolism in the bone tissue of the tooth socket and speed up the process of correcting the bite in patients.