Bite

Bite - the relationship between the upper and lower teeth in their closure (occlusion). There are bite milk teeth (up to 6 years of age), removable bite (from 6 to 13 years, when milk teeth are consistently fall and they are replaced by permanent teeth and bite permanent teeth (see the Teeth).
For anatomical and functional characteristics of the bite is divided into physiological, anomally and pathological.
At physiological bite milk teeth are arranged in a semicircle on both jaws, and the regular - shaped populipsi on the upper jaw and a parabola - on the lower jaw. The middle line that runs between the Central incisors, divides the jaw in two halves. The front teeth of the upper jaw usually overlap the front teeth of the lower jaw (sometimes Vice versa). At physiological bite each tooth upper jaw is in contact with two teeth of the lower jaw, with the exception of the second molar teeth in the bite baby teeth or third molars in the bite of the permanent teeth that are in contact only with the same teeth-antagonists.

physiological bite
Fig. 1. Physiological bite: 1 - ortografia; 2 - progeny; 3 - level bite.
malocclusion
Fig. 2. Types anomaliyah of bites:
1 - excessive development of both jaws;
2 - excessive development of the upper jaw;
3 - excessive development of the lower jaw;
4 - development of both jaws;
5 - the underdevelopment of the upper jaw;
6 - the underdevelopment of the lower jaw;
7 - open the bite;
8 - deep bite.
the decrease bite
Fig. 3. The reduction of the bite: 1 - at the loss of teeth; 2 - when erasing hard tissues of the tooth.

In physiological bite there are several varieties. Ortografia - the teeth of the upper jaw overlapping the lower jaw teeth (Fig. 1, 2). Progeny (physiological) - front teeth of the lower jaw overlap the front teeth of the upper jaw (Fig. 1, 2).
Level bite - wipeabate the ratio of front teeth (Fig. 1,3). Upregulate - front teeth are scissor and tilted forward, forward sloping areas of alveolar process.
Anomaline (incorrect) bite call this kind of bite, when broken physiological ratio teeth - many teeth do not have occlusal contact with the teeth-antagonists. Often, this bite is mixed - some incisors of the upper jaw trump those of the lower incisors and other cutters are in inverse proportion.
The following types anomalies bite. Excessive development of both jaws. The front teeth are, between them there are gaps; soft tissue prirodopol region massive, lips are issued forward (Fig. 2, 1). Excessive development of the upper jaw - pregnate. The upper jaw and teeth are issued ahead of a developed jaw, between the front teeth no occlusal contact. The upper lip is usually shorter and does not provide for closure of the lip (Fig. 2, 2). Excessive development of the lower jaw and progeny. The lower jaw is sharply compared to a developed upper jaw, between the front teeth are the gaps, occlusal contact is absent. The lower lip is thrown forward (Fig. 2, 3). The underdevelopment of both jaws. The lower part of the face shortened and as it shifted backwards, dramatically highlights the size of the nose. Teeth are very closely. Many of them are out of dentition, some not erupt. The ratio of dental rows of mixed type (Fig. 2, 4). Underdevelopment of the upper jaw. Upper lip drops dramatically highlights the size of the nose. On the upper jaw some teeth are out of the dentition. The ratio of dental rows progeniese (Fig. 2, 5). Underdevelopment of the lower jaw. The lower lip sink down, chin significantly shifted backwards, pronounced mental depression. The person takes the form of the so-called bird. The teeth of the lower jaw are not placed in the dentition. The ratio of dental rows prognathism (Fig. 2, 6). The open bite. The gnashing of teeth there is a lack of contact between many teeth, mainly the front (Fig. 2, 7). Deep bite. The upper incisors are deeply overlapping the lower is the consequence of underdevelopment jaws vertically (Fig. 2,8).
Malocclusion is formed from a physiological or anomalies, if there is abnormal wear of the teeth, the defeat of periodontal or violates the integrity of the dentition, for example at the loss of teeth-antagonists; when erasing the chewing surfaces and the cutting edge of the tooth is formed declining bite (Fig. 3).
At the various types of anomalies bite can come pathological changes in the periodontium, and offset the lower jaw in a vertical direction. Thus owing to injury fibers chorda tympani joint heads of the lower jaw, a so-called syndrome Kostina, which is expressed in the emergence of noise in the ears, headaches, neuritis speaking and trigeminal nerves, paresthesias.
In pathological bite arise inflammatory and destructive processes in periodontal, dry mouth (see Xerostomia), appear parestesia to the mouth, pain in the facial area - all these phenomena are called pathological syndrome occlusion.
Malocclusion in children and in adults correct application of special orthodontic appliances (see Orthodontic treatment), it is sometimes necessary to resort to surgical operations.
In the period mixed dentition some permanent teeth erupt out of the arc; usually this is due to the fact that the corresponding milk tooth stayed in the hole and was not promptly removed. With the growth of this tooth usually shifted to its place in the dentition.


Bite - the relationship between the tooth rows of the upper and lower jaw, where joint head of the lower jaw are placed in joint cavities at the base of the slope tuberculum articulare. Closing contact of the teeth is called occlusion and is a particular form of articulation (see Articulation of teeth). Occlusion of the dental arches divided into sagittal (front-back), transversal (side) and vertical (Central). This division coincides with the phases of the chewing.
Central occlusion is the initial and final stage grinding food; when this occlusion all the teeth of the upper and lower jaws are maximum contact. Sagittal occlusion is characterized by the extension of the lower jaw forward to the edge of closing of the front teeth. The lower front teeth slip on the lingual surfaces of the upper front teeth to the edge of closing. This path was named tool. Side (transversal) occlusion is characterized by a lateral displacement of the lower jaw alternately in opposite directions with the movement of the teeth in the transverse direction.
Distinguish bites milk, removable and permanent. In the development of milk bite mark the two periods: from 2.5 to 3.5 years and 3.5 to 6 years. Removable bite covers the age from 6 to 13 years, when milk teeth in a certain sequence drop out, and in their place erupting permanent.
When the permanent dentition tooth arc of the upper jaw has the form of populipsi, and the bottom of the parabola. Teeth are flush with each other and are in contact with their convex parts (contact points). The teeth are in a relationship that is characterized by the fact that under normal bite each tooth upper jaw in contact with the same name and posadistas tooth in the lower jaw. The exception is the lower Central incisor and the upper third molars that during the clamping jaws affect only the title of the teeth. Chewing teeth of the upper and lower jaw during closing tightly in contact with each other. Buccal hills teeth in the upper jaw slightly overlapping the lower. The front teeth of the upper jaw with their cutting edges overlapping the lower teeth on 1,5-2 mm Between the Central incisors of the upper and lower jaws vertically you can spend middle line, which divides the jaw in two equal parts. The teeth of the upper jaw tilted outwards, and the teeth of the lower - inside, making tooth arc upper jaw is much broader and longer than the lower one.
The surface that passes through the cutting edges of the front and the chewing surface of the lateral teeth, called occlusion. In the posterior teeth of the upper jaw occlusal surface has a bulge in the vertical direction; accordingly this bulge on the lower jaw has concavity. Convexity and concavity, starts from the medial surface of the first premolar and ends at the distal thigh third molar teeth of the lower jaw. Occlusal surface in the posterior teeth are also called compensation.


Fig. 1. Types of normal bites: 1 - ortografia; 2 - Artogeia, 3 - upregulate, 4 - progeny (lower progname).

Types normal bite. Depending on the direction of alveolar process with teeth in position Central occlusion of the following types of bite (Fig. 1). Orthognathic type of occlusion can be in two versions: a) overlapping, scissor bite, when the upper front teeth closely overlapping the lower of 1 to 2 mm, and b) ortopedicheski - direct, sizeably, bite, when the cutting edge of the lower front teeth come in contact with the cutting edges of the upper teeth. When bobrovytska type front teeth together with alveolar both jaws slightly bent forward. Prognathism type P. characterized by the fact that the front teeth with alveolar bone of the upper jaw partly put forward. When provence.com type of bite front teeth with alveolar bone of the lower jaw protruding towards the body of the jaw; their cutting edge overlap on 1-2 mm outer surface of edges of the upper front teeth.


Fig. 2. Pathological pregnate: 1 - side view; 2 - bottom view.

Types of pathological bite. Deviations in the relationship teeth come in the form of prognathy, protrusions, open and reduced bite.
Pregnate due to the underdevelopment of the lower or excessive development of the upper jaw. The upper jaw is so often comes forward that the lower front teeth do not touch the upper and between them there remains a large gap (Fig. 2). This form of prognathy often complicated by deep rescoweb overlap, resulting in lower front teeth forward and injure their cutting edges of the mucous membrane of the sky. Such malocclusion adversely affects the appearance of the patient, chewing and diction.


Fig. 3. Pathological progeny: 1 - the first form, 2 - second kind.

Fig. 4. The scheme is open bite.

Progeny is characterized by the following features: lower jaw put forward toward the front towards the upper jaw. Pathological progeny can be of two types (Fig. 3): a) when only the lower front teeth noticeably bent forward and do not touch the top, and the ratio of the lateral teeth remains as with orthognatic bite; b) when the whole set of teeth of the lower jaw is located in front of the upper. Between the upper and lower front teeth formed period, chin is thrown forward. The front upper teeth can injure the mucous membrane of the gingival margin from the lingual side of the incisors of the lower jaw. Thus broken chewing (especially phase biting), and diction. The treatment is carried out with the help of orthodontic appliances (see Orthodontic method and treatment), in more severe cases, surgery.
When the open bite the gnashing of the upper and lower teeth in contact only one or two lateral teeth, and the rest do not touch (Fig. 4).


Fig. 5. Pathological abrasion to prosthetics.

Declining bite occurs when excessive abrasion, cutting and chewing surfaces of the teeth resulting in the reduction, lower third of the face is reduced significantly, naso-lip folds more pronounced violated the act of chewing. However, frequent changes in the temporomandibular joint, contributes to the development of pathological syndrome occlusion (see Kostina syndrome). These patients should be carefully screened not only a neurologist, but mainly by a dentist-orthopedist and radiologist. At definition of pathological syndrome occlusion, the nature and extent of displacement of joint heads produce the appropriate detachable equipment, normalizing the required ratio joint heads in the temporomandibular joint.
Malocclusion in childhood eliminate the use of special orthodontic appliances. Adults often resort to surgical interventions on the jaw in the form of step, wedge and other osteotomy, mainly on the lower jaw, by moving bone fragments together with teeth, seeking lengthening or shortening of the jaw and the establishment of normal bite. Cm. also the Jaw.