Overbite

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Overbite vertical (overbite) and horizontal (overjet)
Human scissor bite
Overshot (overjet <0) in a dog of a breed with brachycephaly : the front of the lower jaw lies in front of the front of the upper jaw.

The term overbite describes as an umbrella term the positional relationship of the upper anterior teeth to the lower anterior teeth . A distinction is made between overjet and overbite . It is not a diagnosis of a misalignment, but a description of the situation. If the position of the upper and lower incisors is optimal, one speaks of a scissor bite. Only when the overjet or the overbite deviate from the norm can it be a problem that needs to be corrected.

Overjet

Under overjet is defined as the horizontal (anterior-posterior) overbite ( English overjet ) - the positional relationship of the front teeth in the horizontal plane. The greatest distance between the cutting edges of the central incisors above and below is measured. The specification is made in millimeters . If the cutting edges bite together, the value is zero. If the upper front teeth are in front of the lower front teeth, the overbite is indicated with a positive number, the lower front teeth with a negative number of millimeters. One then speaks of an underbite or an undershot .

Overbite

Under overbite is defined as the vertical (superior-inferior) overbite (engl. Overbite ) - the positional relationship of the front teeth in the vertical. The distance from cutting edge to cutting edge is measured. If the cutting edges bite together, the value is zero. If the incisal edges do not come into contact with maximum occlusion , one speaks of a frontally open bite . If the upper anterior teeth cover the lower anterior teeth, one speaks of a deep bite . If the lower front teeth are completely covered, this is called a cover bite .

Head bite

Frontal head bite

If the overbite is zero both horizontally and vertically, one speaks of a head bite or tête-a-tête bite , which can be accompanied by a cross bite . The unphysiological pressure and mechanical stress on the incisors when chewing causes wear and tear, which creates small chewing surfaces on the incisors. The enamel is ground off.

Diagnosis

A eugnathes (normal) dentition has a horizontal overbite of 2 to 3 mm and a vertical one of 1 to 2 mm. The upper anterior teeth are slightly in front of the lower anterior teeth and cover them by 1 to 2 mm. The term overbite is colloquially often equated with an enlarged horizontal overbite. Overbite is not a diagnosis , just a measure that can be part of a diagnosis. The type and size of the overbite cannot always be used to determine the angle class of the bit. However, there is a certain correlation between class II and an enlarged horizontal overbite, as well as class III and a negative horizontal overbite.

Treatment needs

Whether and when an enlarged overbite needs to be treated depends on a number of other factors. As a guide value for the horizontal overbite, according to the Index of Orthodontic Treatment Need (IOTN), there is a moderate treatment need at ≥ 6 mm and a clear treatment need at ≥ 9 mm. The orthodontic indication groups in statutory health insurance resulted from the IOTN .

Index of Orthodontic Treatment Need in relation to Overjet and Overbite

The need for treatment is determined in five degrees. With regard to the overjet, the following classification results:

  • Grade 1: no need for treatment
  • Grade 2: minor anomaly, no need for treatment
    • 2.a Overjet> 3.5 mm and ≤ 6 mm (with competent lip closure)
    • 2.b reverse overjet between 0 and ≤ 1 mm
  • Grade 3: borderline need for treatment
    • 3.a Overjet> 3.5 mm and ≤ 6 mm (incompetent lip closure)
    • 3.b reverse overjet between 1 and ≤ 3.5 mm
  • Grade 4: need for treatment
    • 4.a Overjet> 6 mm and ≤ 9 mm
  • Grade 5: need for treatment
    • 5.a enlarged overjet> 9 mm

With regard to the overbite, the following classification results:

  • Degree 0> 3 mm
  • Grade 2f ≥ 3.5 mm (without gingiva contact)
  • Grade 3f deep overbite (with contact, without trauma)
  • Grade 4f deep overbite (with traumatic contact)

See also

Web links

Wiktionary: Underbite  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ Bärbel Kahl-Nieke: Introduction to orthodontics: diagnostics, treatment planning, therapy: with 10 tables . Deutscher Ärzteverlag, 2010, ISBN 978-3-7691-3419-3 , p. 92–.
  2. ↑ Andrea Wichelhaus: Orthodontics - Therapy Volume 1: Basic treatment concepts . Georg Thieme Verlag, December 12, 2012, ISBN 978-3-13-160151-3 , pp. 187–.
  3. ^ WR Proffit et al. Contemporary Orthodontics , Mosby, 4th edition, p. 11, ISBN 0-323-04046-2
  4. ^ A b Thomas Weber: Memorix dentistry . Georg Thieme Verlag, 2010, ISBN 978-3-13-114373-0 , p. 196.