Effects of maxillary protraction with skeletal anchorage and petit-type facemask in high-angle class III patients: a retrospective study

Abstract

Introduction: Skeletal anchorage-supported applications are performed to increase the skeletal effect of maxillary protraction used in the treatment of Class III malocclusions related to maxillary retrognathia. Aim: To assess the craniofacial and soft tissue effects of the maxillary protraction with skeletal anchorage and Petit-type facemask in high-angle growth Class III young adolescent patients due to maxillary retrognathia. Materials and Methods: The archives for this retrospective study were scanned according to inclusion criteria as follows: skeletal Class III malocclusion due to maxillary retrognathia, high-angle growth pattern, treated using face mask with miniplate anchorage. This study consisted of 15 patients (7 females and 8 males; mean age,11.96±1.03 years) treated using Petit-type face mask with miniplate anchorage inserted in maxillae. Face-mask was used with an approximately 500 g force applied bilaterally from the hooks of the mini plates. Patients used Petit-type face mask for a total of 6 months for the first three months throughout the day, the next 3 months for 12 hours a day. Cephalometric measurements were made to evaluate the effects of the maxillary protraction. The paired t-test was applied to evaluate differences between pre- and posttreatment variables. Results: In our study, the skeletal Class III relationships were improved; maxillary measurements significantly increased (SNA° 3.48±0.42°; A–VRL 3.94±0.81 mm), SNB° decreased (-0.50±0.30°), ANB° increased (3.85±0.46°) (p<0.001) and SNGoGn° slightly increased (0.25±0.21°) (p>0.05). The maxillary and mandibular incisors showed retroclination (-3.12±0.42° p<0.01;-0.46±0.24°; respectively). The changes in skeletal and dental parameters caused a significant increase in overjet (3.56±1.01 mm; p<0.001). Conclusion: Using skeletal anchorage with Petit-type facemask has been successfully treated in patients with high-angle Class III young adolescent patients that provided an average increase in maxillary skeletal and soft tissue structures of 3.9 mm and undesired effects of conventional face mask treatment on vertical dimensional measurements were reduced.