Crossbite is a pathology of the closure of the dentition, due to the discrepancy of their size and shape in the transverse direction. Crossbite is manifested by pronounced facial asymmetry, speech defects, biting of the cheek mucosa, impaired chewing function, pain in the TMJ area. The diagnosis of crossbite is facilitated by clinical data, functional tests, the manufacture and study of diagnostic models of the jaws, TRG with X-ray cephalometric analysis, orthopantomography, TMJ radiography. Treatment of crossbite is carried out with the help of various, individually selected removable and non-removable orthodontic devices.
Meaning
Crossbite is a type of malocclusion characterized by the intersection (crossing) of the dentition when closing the jaws. The prevalence of crossbite in dentistry ranges from 0.4-2% in childhood and adolescence to 3% among adults. Crossbite refers to transversal occlusion anomalies. To characterize the crossbite, the terms “oblique”, “lateral” bite, laterodeviation, laterogeny, laterognathia, lateroposition, etc. are also used. Despite the fact that crossbite is less common in the population than distal, mesial, deep or open, it is one of the most severe occlusion disorders requiring long-term active orthodontic treatment and a long retention period.
Causes
The prerequisites for the formation of a crossbite can be congenital and acquired. Factors of the congenital order include hereditary conditionality, improper laying of dental rudiments, disorders of the development of the jaws and temporomandibular joint, cleft palate, macroglossia, birth trauma, etc.
More often, crossbite develops under the influence of factors acting in the postnatal period. This may be due to a violation of teething (retention, sequence change); bruxism; violation of chewing function with premature tooth loss, multiple caries. Often, crossbite is a consequence of incorrect behavior stereotypes: bad habits (propping up the cheek with a fist, sucking fingers, biting the lip), sleep posture disorders (sleeping on one side with a hand placed under the cheek). The causes of crossbite may be diseases associated with impaired mineral metabolism (rickets), difficulty in nasal breathing (rhinitis, adenoids, sinusitis), facial hemiatrophy, polio, osteomyelitis of the jaws, ankylosis of the TMJ, arthritis of the TMJ, etc.
The opinion is substantiated that malocclusion in children (including crossbite) may be a consequence of dysplastic changes in the musculoskeletal system (posture disorders, scoliosis). The formation of a crossbite is possible if rehabilitation measures are not followed after uranoplasty, facial skeleton injuries.
Classification
In orthodontics, various variants of the classification of crossbite have been proposed. So, according to one of them, the authors distinguish dental alveolar (with localization of changes within the dental arches and alveolar process), gnatic (with localization of changes within the dental arches and jaws) and articular crossbite (associated with a change in the position of the lower jaw).
The most common in clinical practice is the classification that distinguishes the following forms of crossbite:
- Buccal crossbite can be with or without displacement of the lower jaw, unilateral or bilateral. Buccal bite is based on the narrowing of the upper dentition and /or jaw, the expansion of the lower dentition and / or jaw on one or two sides. When the dentition is closed, it is characterized by overlapping of the buccal bumps of the upper teeth with buccal bumps of the lower ones.
- Lingual crossbite (one- and two-sided) is caused by the expansion of the upper dentition and/or jaw, narrowing of the lower dentition and /or jaw also on one or both sides. When the dentition is closed, it is characterized by overlapping of the buccal bumps of the lower teeth with palatal bumps of the upper teeth.
- Buccal-lingual crossbite combines the signs of the first two.
Symptoms
Each form of crossbite has its own specific clinical manifestations and signs. Common to this malocclusion is a violation of symmetry and, consequently, the aesthetics of the face. At the same time, the patient’s chin with a crossbite is shifted to the side, the upper lip on the same side sinks, the opposite side of the lower part of the face is flattened.
Intraoral signs of a crossbite may include the expansion or narrowing of one dentition, displacement of the lower jaw, violation of the contact of the lateral teeth, crossing of the dentition when closing the jaws, mismatch of the location of the bridles of the lower and upper lip.
With various forms of crossbite, due to a decrease in the number of occlusive contacts, the function of chewing is disrupted; at the same time, biting of the cheek mucosa is often noted. Incorrect speech articulation (dyslalia) mainly concerns lingual phonemes.
With a crossbite, there is often a crunch and soreness when opening the mouth, blocking of the lower jaw – TMJ dysfunction develops; in the future, there is a high risk of developing deforming TMJ arthrosis. Uneven distribution of masticatory pressure contributes to periodontal tissue damage – the occurrence of periodontitis and periodontal disease.
Diagnostics
The orthodontic diagnosis is preceded by a complete clinical, functional and instrumental examination. During the initial consultation, the orthodontist examines the face and oral cavity, performs palpation and auscultation of the TMJ, performs the necessary functional tests, compares objective data with complaints and anamnestic information.
The further algorithm involves the determination of a constructive bite, the production and analysis of diagnostic models of the jaws, the study of orthopantomograms and direct telerentgenograms of the head. To detect the displacement of the lower jaw with a crossbite, a TMJ radiography is required.
During the examination, the type and form of crossbite, its etiology, concomitant disorders are established, which affects the volume and sequence of implementation of therapeutic measures.
Specialists such as a speech therapist, neurologist, otorhinolaryngologist, pediatrician, etc. can participate in the comprehensive diagnosis of disorders associated with crossbite.
Treatment
Orthodontic treatment of crossbite is aimed at normalizing the relationship of dentition in the transversal plane.
During the period of temporary bite, the child is recommended to chew solid food, perform myogymnastics, grind the bumps and cutting edges of the teeth, in case of early loss of milk molars, removable prosthetics.
In late temporary and mixed occlusion, instrumental treatment is widely used with the help of functional devices (Janson bionator, Frenkel function regulator, Klammt activator, Andresen-Goyle activator, etc.), as well as extraoral systems (head caps with chin sling and rubber traction).
With the formation of a permanent bite, treatment is carried out with non-removable orthodontic devices of mechanical action: Engl’s apparatus, Katz crowns, braces, followed by the wearing of retainers. According to orthodontic indications, in case of crossbite, surgical treatment is additionally performed – removal of individual teeth, compactosteotomy.
Prognosis and prevention
At the beginning of treatment during the period of temporary occlusion, normalization of occlusive relationships can be achieved with the help of conservative measures. Pronounced facial asymmetry at the late onset of crossbite treatment in some cases can only be eliminated surgically.
Prevention of crossbite involves a systematic visit to the dentist, the eradication of bad habits, monitoring the correct posture and position of the child during sleep, normalization of nasal breathing, etc. It is advisable to identify and eliminate diseases and anomalies of teeth in childhood: this contributes to the correct formation of dental arches, prevention of the formation of crossbite, facial asymmetry, periodontal pathology and temporomandibular joint.
Literature
- Korkhaus G. Gebiss-, Kiefer- und Gesichtsorthopadie // Handbuch der Zahnheilkunde, Bd. IV. — München: Bergmann, 1939.
- Reichenbach E., Bruckl H. Kieferorthopadische Klinik und Therapie. — Barth, Leipzig 1967.
- Aparna P., Dilip K.N. Ortodontics, posterior crossbite // StatPearls. — 2018. link
- Carlson D.E. Physiological occlusion // Midwest Press. – 2009. — 218 p.
- Persin L.S. Orthodontics. — M., Medicine, 1996. — pp. 48, 66.
