Miniplate implant for maxillary protraction in Class III patient

Objectives: To investigate the effects of using miniplate implant as anchorage for maxillary protraction in Skeletal Class III malocclusion with retruded maxilla. Methods: Totally 9 patients with Skeletal Class III malocclusion were included in this study, in whom 5 are females, and 4 are males. They are aged from 11 to 14 years old, with 11.8 years in average. The miniplate implants were placed between the upper lateral incisors and canines on both sides in each patient. The facemask was used 1 month after miniplate implant surgery, and 450 grams of force was loaded for maxillary protraction on each side. Treatment duration was from 6 to 12 months, with 8 months in average. The profile of each patient was taken before and after protraction, and cephalometric analysis was used for assessment. Statistically, paired t-test was used. Results: After protraction, SNA angle increased by 4.04 degrees (from 77.06 to 81.11 degrees in average), and ANB angle decreased by 3.45 degrees (from –4.90 to –1.45 degrees in average) The significant difference was found( P<0.001). While, SNB angle increased by 0.59 degrees (from 81.97 to 82.56 degrees in average), but no significant difference was detected (P=0.56>0.5). U1PP angle increased by 0.02 degree (from 123.97 to 123.99 degrees in average), and no significant difference was detected (P=0.99>0.05). L1MP angle decreased by 1.52 degrees (from 85.99 to 84.47 degrees in average), but no significant difference was found (P=0.5>0.05). Conclusion: The result showed to us that miniplate implant is good anchorage for promoting forward growth of maxilla with less dental effect following maxillary protraction.