Analysis of efficacy of functional appliances on mandibular growth

The purpose of this study was to examine the hypothesis that functional appliances enhance mandibular growth in the treatment of skeletal Class II malocclusions. We systematically reviewed previously published randomized controlled trials. A MEDLINE search strategy for the years 1966 to 1999 was developed and implemented. Six articles meeting validity standards were evaluated for 12 clinical measures. The following linear measures were assessed: condylion-pogonion (Co-Pg), articulare-pogonion (Ar-Pg), condyliongnathion (Co-Gn), articulare-gnathion (Ar-Gn), sella-gonion (S-Go), articulare-gonion (Ar-Go), and condyliongonion (Co-Go). Two angular parameters, sella-nasion-B point (SNB) and lower incisal angle (LIA), were also measured. Three horizontal measurements were also variably used in the studies examined: gonion-menton (Go-Me), pogonion to N (Pg to N), and gonion-pogonion (Go-Pg). For Co-Pg, Co-Gn, SNB, LIA, and other horizontal measurements, we found no significant difference between the untreated control group and the group treated with functional appliances. However, for Ar-Pg and Ar-Gn, there was a significant difference between the control and the treated groups. Although these appliances can be used for other purposes, these results suggest the need to reevaluate functional appliance use for mandibular growth enhancement. These results complement those of quasi-experimental studies with discriminant analysis but differ from nonsystematic reviews that provide qualitative summaries.