Treatments for adults with prominent lower front teeth

Prominent lower front teeth may be associated with a large or prominent lower jaw and/or a small or retrusive upper jaw. The reasons why this occurs are not well understood. Several treatments have been proposed including orthopedics, functional appliances, interceptive and/or corrective orthodontics, and surgery for the more severe cases, but we found only two trials, each evaluating a different approach. Both of the trials were small and did not provide adequate data for assessing the effectiveness of the treatments.

There is insufficient evidence, from the two included trials, to conclude that any surgical treatment for prominent lower front teeth is better or worse than another.

Authors' conclusions: 

There is insufficient evidence from the two included trials, to conclude that one procedure is better or worse than another. The included trials compared different interventions and were at high risk of bias and therefore no implications for practice can be given. Further high quality randomized controlled trials with long term follow-up are required.

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Background: 

Prominent lower front teeth may be associated with a large or prognathic lower jaw (mandible) or a small or retrusive upper jaw (maxilla). Edward Angle, who may be considered the father of modern orthodontics, classified the malocclusion in this situation as Class III. The individual is described as having a negative or reverse overjet as the lower front teeth are more prominent than the upper front teeth.

Objectives: 

The purpose of this systematic review was to evaluate different treatments of Angle Class III malocclusion in adults.

Search strategy: 

The following databases were searched: Cochrane Oral Health Group Trials Register (to 22 March 2012); CENTRAL (The Cochrane Library 2012, Issue 1); MEDLINE via OVID (1950 to 22 March 2012); EMBASE via OVID (1980 to 22 March 2012); LILACs (1982 to 22 March 2012); BBO (1986 to 22 March 2012); and SciELO (1997 to 22 March 2012).

Selection criteria: 

All randomized or quasi-randomized controlled trials of treatments for adults with an Angle Class III malocclusion were included.

Data collection and analysis: 

Three review authors independently assessed the eligibility of the identified reports. Two review authors independently extracted data and assessed the risk of bias in the included studies. The mean differences with 95% confidence intervals were calculated for continuous data.

Main results: 

Two randomized controlled trials were included in this review. There are different types of surgery for this type of malocclusion but only trials of mandible reduction surgery were identified. One trial compared intraoral vertical ramus osteotomy (IVRO) with sagittal split ramus osteotomy (SSRO) and the other trial compared vertical ramus osteotomy (VRO) with and without osteosynthesis. Neither trial found any difference between the two treatments. The trials did not provide adequate data for assessing effectiveness of the techniques described.

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