Treatment effect of combined maxillary protraction and chincap appliance in severe skeletal Class III cases

The present study was designed to evaluate the true treatment effects of the maxillary protracting appliance with chincap for skeletal Class III cases and to evaluate the difference of true treatment effects between the cases in which the maxilla was protracted from the first molars and the cases protracted from the first premolars. Cephalograms of 63 cases (the first molar protraction group--27 cases protracted from the first molars, the first premolar protraction group--36 cases protracted from the first premolars) treated with the combined maxillary protraction and chincap appliance were used. Template analysis was performed to evaluate the estimated treatment effects without growth change. Forward movement of the maxilla and backward rotation of the mandible were characteristic features of the estimated treatment effects in 63 cases. In comparing the two groups, the maxilla was displaced more anteriorly and rotated more upward and forward in the first molar protraction group. Therefore, the intraoral site of protraction should be selected by considering vertical dimensions of skeletal and dental structures, and the amount of forward displacement of the maxilla required in the treatment of the individual patient.