Early orthodontic treatment reduced incisal trauma in children with class II malocclusions

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

Randomised controlled trials (RCTs) of orthodontic treatments (either one- or two-phase) with any type of orthodontic braces (removable, fixed, functional) or head-braces compared with late treatment with any type of orthodontic braces or head-braces; or, on any type of orthodontic braces or head-braces compared with no treatment or another type of orthodontic brace or appliance to correct prominent upper front teeth.

Study selection, risk of bias assessment and data extraction were carried out independently by at least two reviewers. The primary measure of effect was over jet measured in millimetres or by any index of malocclusion. Odds ratios (ORs) and 95% confidence intervals (CIs) were used for dichotomous outcomes, mean differences (MDs) and 95% CIs for continuous outcomes and a fixed- effect model for meta-analyses as there were fewer than four studies.

Seventeen studies involving 791 patients were included. The overall quality of the evidence was low with only two of the 17 studies being assessed as at low risk of bias. Three trials (n = 343) compared early (two-phase) treatment (7-11 years of age) with a functional appliance with adolescent (one-phase) treatment.Statistically significant differences in over jet, ANB and PAR scores were found in favour of functional appliance when the first phase of early treatment was compared with observation in the children due to receive treatment in adolescence. However, there was no evidence of a difference in the over jet between the groups at the end of treatment. A statistically significant reduction in the incidence of incisal trauma (OR 0.59, 95% CI 0.35 to 0.99, P = 0.04) in favour of two-phase treatment with functional appliance was seen. The incidence of incisal trauma was clinically significant with 29% (54/185) of patients reporting new trauma incidence in the adolescent (one-phase) treatment group compared to only 20% (34/172) of patients receiving early (two-phase) treatment.Two trials (n = 285) compared early (two-phase) treatment using headgear, with adolescent (one-phase) treatment. Statistically significant differences in over jet and ANB were found in favour of headgear when the first phase of early treatment was compared with observation in the children due to receive treatment in adolescence. However, there was no evidence of a difference in the over jet between the groups at the end of treatment. The incidence of incisal trauma was, however, statistically significantly reduced in the two-phase treatment group, the adolescent treatment group having twice the incidence of incisal trauma (47/120) compared to the young children group (27/117).Two trials (n = 282) compared different types of appliances (headgear and functional appliance) for early (two-phase) treatment. At the end of the first phase of treatment statistically significant differences, in favour of functional appliances, were shown with respect to final over jet only. At the end of phase two, there was no evidence of a difference between appliances with regard to over jet, PAR score or the incidence of incisal trauma.Late orthodontic treatment for adolescents with functional appliances showed a statistically significant reduction in over jet of -5.22 mm (95% CI -6.51 to -3.93, P < 0.00001) and ANB of -2.37° (95% CI -3.01 to -1.74, P < 0.00001) when compared to no treatment (very low quality evidence).There was no evidence of a difference in over jet when Twin Block was compared to other appliances. However, a statistically significant reduction in ANB (-0.63°, 95% CI -1.17 to -0.08, P = 0.02) was shown in favour of Twin Block. There was no evidence of a difference in any reported outcome when Twin Block was compared with modifications of Twin Block.

The evidence suggests that providing early orthodontic treatment for children with prominent upper front teeth is more effective in reducing the incidence of incisal trauma than providing one course of orthodontic treatment when the child is in early adolescence. There appear to be no other advantages for providing treatment early when compared to treatment in adolescence.