Limited evidence on treatments for distalising upper first molars in children and adolescents.

DATA SOURCES: The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Embase.

STUDY SELECTION: Randomised clinical trials (RCTs) involving the use of removable or fixed orthodontic appliances intended to distalise upper first molars in children and adolescents.

DATA EXTRACTION AND SYNTHESIS: Study selection, risk of bias assessment and data extraction were carried out independently by at least two reviewers. For dichotomous outcomes the measure of treatment effect was the risk ratio; for continuous outcomes the measure of treatment effect was the mean difference. Data analysis followed Cochrane protocols.

RESULTS: Results Ten studies (involving 354 patients) were included in this review. Study quality was generally poor; seven studies were assessed to be at high risk of bias and three of unclear risk of bias. Meta-analyses were conducted where appropriate. Four studies (159 patients) compared a distalising appliance to an untreated control. The degree and direction of molar movement and loss of anterior anchorage varied with the type of appliance. Four studies involving (150 patients) compared a distalising appliance versus headgear. The mean molar movement for intraoral distalising appliances was -2.20 mm and -1.04 mm for headgear.There was a statistically significant difference in mean distal molar movement (mean difference (MD) -1.45 mm; 95% confidence interval (CI) -2.74 to -0.15) favouring intraoral appliances compared to headgear. However, a statistically significant difference in mean mesial upper incisor movement (MD 1.82 mm; 95% CI 1.39 to 2.24) and overjet (fixed-effect: MD 1.64 mm; 95% CI 1.26 to 2.02; two studies, unclear risk of bias, 70 participants analysed) favoured headgear, ie there was less loss of anterior anchorage with headgear. Owing to variation in interventions, direct comparisons of intraoral appliances from three studies (93 patients), high or unclear risk of bias was reported narratively. All appliances were reported to provide some degree of distal movement, and loss of anterior anchorage varied with the type of appliance. No included studies reported on the incidence of adverse effects (harm, injury), number of attendances or rate of non-compliance.

CONCLUSIONS: It is suggested that intraoral appliances are more effective than headgear in distalising upper first molars. However, this effect is counteracted by loss of anterior anchorage, which was not found to occur with headgear when compared with intraoral distalising appliance in a small number of studies. The number of trials assessing the effects of orthodontic treatment for distilisation is low, and the current evidence is of low or very low quality.