The effectiveness of protraction face mask therapy: A meta-analysis

This study examined the effectiveness of maxillary protraction with orthope dic appliances in Class III patients. A meta-analysis of relevant literatur e was performed to determine whether a consensus exists regarding controver sial issues such as the timing of treatment and the use of adjunctive intra oral appliances, An initial search identified 440 articles relating to Clas s III malocclusion. Among those articles, 11 studies in English and 3 studi es in foreign languages met the previously established selection criteria. Data from the selected studies were categorized by age and appliance groups for the meta-analysis. The sample sizes were comparable between the groups , The statistical synthesis of changes before and after treatment in select ed cephalometric landmarks showed no distinct difference between the palata l expansion group and nonexpansion group except for 1 variable, upper incis or angulation, which increased to a greater degree in the nonexpansion grou p. This finding implies that more skeletal effect and less dental change ar e produced in the expansion appliance group. Examination of the effects of age revealed greater treatment changes in the younger group. Results indica te that protraction face mask therapy is effective in patients who are grow ing, but to a lesser degree in patients who are older than 10 years of age, and that protraction in combination with an initial period of expansion ma y provide more significant skeletal effects. Overall mean values and corres ponding standard deviations for the studies selected can also be used to es timate mean treatment effects expected from the use of protraction face mas k.