Do lip bumpers work?

Searches were made using PubMed, Embase, the Cochrane Central Register of Controlled Trials and the Cochrane database of systematic reviews, along with searches by hand of the following journals: Angle Orthodontist, American Journal of Orthodontics and Dentofacial Orthopedics, Journal of Orthodontics and European Journal of Orthodontics.

The first step was to identify eligible reports based on their titles and abstracts: 52 articles were found. Inclusion and exclusion criteria were then applied. Studies were included if subjects were human; they were randomised controlled trials and prospective or retrospective studies; they discussed the effect of the lip bumper on the arch and teeth; and they were reported in the English language. Articles excluded were mainly animal studies, case reports, case series, review articles, abstracts, in-vitro studies, discussions and interviews; were published in a language other than English; or did not follow the objective of this review. The selection was made by two researchers. Their results were compared to identify discrepancies and reach mutual agreement.

If two or more studies had evaluated the same technique, a meta-analysis was planned.

A total of 16 RCT were identified of which 13 underwent detailed evaluation; of these, only one study was considered to have usable outcome information. The others were excluded because of control group, sex, age, study casts and cephalometric analysis, and measurement error. This single small study showed that lip bumper can increase arch dimensions and contribute to crowding relief in mixed dentition.

The results showed increases in arch dimensions, including a greater arch length. This was attributed to incisor proclination, distalisation, and distal tipping of the molars. There were also increases in arch width and intercanine and deciduous intermolar or premolar distances. The long-term stability of the effects of the lip bumper need to be elucidated.