Distalny bite – the violation of occlusion caused by promotion of the top tooth alignment forward in relation to lower at close jaws. Front signs of a disteel bite include a vystupaniye of the top jaw, a chin skoshennost ("the bird's person"), shortening of an upper lip and a zapadeniye of lower; oral signs are presented by a nesmykaniye of the upper and lower frontal teeth, the wrong smykaniye of side teeth. Violations of breath, chewing, swallowing, the speech can take place. The Distalny bite is diagnosed on the basis of clinical examination, studying of a front profile, models of jaws, tsefalometrichesky data of a telex-ray analysis, a X-ray analysis or a tomography of VNChS. Treatment of a disteel bite is carried out by means of orthodontic devices (functional devices, briquettes, etc.).
Distalny bite – the option of the wrong bite which is characterized by shift of the lower tooth alignment back in relation to top, a reztsoyovy dizokklyuziya and violation of relationship of side teeth in the sagittalny direction. At children's and teenage age the distalny bite occurs at 6,5-15% examined. In the general structure of zubochelyustny anomalies the share of a disteel bite makes 31%. Along with a mezialny bite (progeniya), disteel occlusion of tooth alignments belongs to sagittalny anomalies of a bite. To a concept a distalny bite in stomatology also there correspond the terms "posterialny bite", "prognatichesky bite" or "prognatiya".
Reasons of a disteel bite
It should be noted that normal at all newborns the lower jaw has disteel situation: it settles down at distance of 1-10 mm behind top therefore between jaws the sagittalny crack is formed. Further, in the course of breastfeeding, a teething and development of function of chewing position of the lower jaw is gradually leveled, it holds normal position rather top, and the distalny bite passes into ortognatichesky. Thus, as one of the reasons of formation of a disteel bite the artificial feeding which is not demanding from the child of special efforts when sucking and, therefore, not stimulating growth of the lower jaw acts.
Anomalies of teeth and bite (including disteel occlusion) occur at 60% of the children who had rickets; at 34% of the children having nasopharynx diseases with violation of nasal breath (adenoides, chronic hypertrophic rhinitis, a curvature of a nasal partition, etc.). The negative contribution to formation of a disteel bite is made by addictions, such as long sucking of a baby's dummy, a finger, toys and other foreign objects, zakusyvany lips.
Also among prichinno significant factors it should be noted deficiency of calcium and fluorine in an organism, absence or insufficient quantity in a diet of the child of early age of firm food, early removal of milk teeth and lack of prosthetics. Besides, the distalny bite can be a consequence of congenital anomalies of development of jaws, a patrimonial trauma, injuries of jaws, violations of a bearing.
Classification of a disteel bite
In orthodontics several classifications of a disteel bite are offered (according to E. Engl, A. I. Betelman, F. Ya. Horoshilkina, L. S. Persin, Yu.M.Malygin, etc.).
So, E. Engl carrying distalyyony occlusion to the II class of a smykaniye of tooth alignments allocated 2 in is mute a subclass:
1 subclass – a fanlike inclination of the top cutters, narrowing of tooth alignments in side sites
2 subclass - a palatal inclination of the central top cutters; a deviation of side cutters towards a lip and turn on an axis; lack of a sagittalny crack between the top and lower cutters.
A. I. Betelman distinguishes several clinical kinds of a disteel bite:
- the top makrognatiya at normally developed lower jaw;
- the lower mikrognatiya at normally developed top jaw;
- the top makrognatiya in combination with the lower mikrognatiya;
- prognatiya with compression of the top jaw in side departments.
On the basis of the morphological changes defined in the analysis of teleroentgenograms, F. Ya. Horoshilkina allocates the gnatichesky, zuboalveolyarny and combined forms of a disteel bite.
Symptoms of a disteel bite
As well as in a case with a deep bite, characteristic signs of a disteel bite can be conditionally divided on front and oral which lead to esthetic and functional violations. Existence of a disteel bite is followed by change of a profile and face proportions due to promotion forward of the top jaw, an underdevelopment or a slanted shape of a chin why the face of the patient sometimes takes a so-called "bird's" form. The upper lip is hitched up; the central top cutters act forward, the lower lip is behind them. The mouth at the patient with a disteel bite is slightly slightly opened, lips are not closed, the podborodochny fold is sharply outlined.
Are the defining intra oral signs of a disteel bite promotion of the upper frontal teeth forward; a nesmykaniye of the top and lower cutters with existence between them a sagittalny crack; violation of a relative positioning of side teeth in the perednezadny direction. Purely distalny bite meets seldom; much more often it is combined with anomalies of position of teeth, diastemy, towers, a deep, open or cross bite, the Gothic sky.
The Distalny bite adversely affects not only appearance of the patient, but also functioning of the zubochelyustny device, respiratory organs and an articulation. At a disteel bite the nibble, a chewing and swallowing of food is at a loss, nasal breath is broken, pain in a temporal and mandibular joint is noted. At children with a disteel bite more often than their peers, have violations of the speech (dislaliya) demanding logopedic correction.
The Distalny bite bears in itself the increased risk of development of caries, diseases of a parodont (a periodontal disease, periodontosis) of the back teeth experiencing excessive chewing strain, VNChS dysfunctions. Existence of a disteel bite is accompanied by technical difficulties of performing prosthetics and dental implantation.
Diagnostics of a disteel bite
The skilled orthodontist can already determine presence at the patient of a disteel bite by external signs. At clinical examination it is paid attention to the sizes of jaws, a relative positioning of tooth alignments, existence of a sagittalny crack, a shape of jaws and an alveolar shoot etc.
For differential diagnostics of a kind of a disteel bite the telex-ray analysis with the subsequent analysis and calculation of rentgentsefalometrichesky indicators is carried out; definition of a constructive bite; production and research of diagnostic models of jaws. For the purpose of assessment of a condition of elements of a temporal and mandibular joint and chewing muscles the X-ray analysis or a tomography of VNChS, an electromyography, a reografiya is used.
Treatment of a disteel bite
Correction of a disteel bite has to begin even before change of temporary teeth by constants. During this period it is shown the treatment directed to control of growth top and stimulation of development of the lower jaw which is performed by means of the removable orthodontic equipment (the regulator of function of Frenkel, a removable plate of Katts, Andrezena-Goypl's activator, the LM activator, etc.). The complex of medical actions can include a miogimnastika, a selective prishlifovyvaniye of teeth, removal of accessory teeth on the top jaw, elimination of addictions, normalization of nasal breath and so forth.
In the period of a replaceable bite a main objective of medical influence is corrections of a form and a ratio of tooth arches what removable plastinochny devices, Hurgina's devices, Gulyaevy, Kurland, Englya, a palatal dilator, preortodontichesky treyner and so forth are used to.
After completion of growth of maxillary bones treatment of a disteel bite can be carried out with use of breket-systems, sometimes in combination with a hardware method (Gerbst's device, a front arch or Sabbakh's spring and so forth). For an exception of a recurrence of a disteel bite after a course of active therapy lasting 3-4 years carrying retentsionny devices (removable or fixed reteyner) during 1,5-2 terms of the main treatment is shown. At some forms of a disteel bite performing surgical treatment (removal of several teeth, a kompaktosteotomiya) is required previously.
Forecast and prevention of a disteel bite
Observance of all recommendations of the orthodontist in the course of treatment of a disteel bite at children and teenagers allows to count on favorable esthetic and functional result. At adult age correction of a disteel bite represents big difficulties and takes longer time.
Prevention of formation of a disteel bite dictates need of breastfeeding of the child, timely transfer of the kid to firm food, his breaking from addictions, performing prevention of rickets, inflammatory diseases of a nasopharynx and violations of a bearing.