以骨釘及左下顎第二大臼齒缺牙區改正下顎前牙擁擠及中線之偏移

本病例為一24歲女性，其上顎左右第一小臼齒及左下第二大臼齒缺失，導致左上第二大臼齒因缺乏對咬牙而逐漸下移，無法進行進一步的膺復治療，且合併下顎前牙擁擠，右側犬齒錯咬，中線偏移至右側；其治療計畫乃於左下第二大臼齒缺牙處植入骨釘，利用骨釘及滑動機制，將下排齒列往左側單一方向做遠心移動，六個月即迅速改正前牙擁擠及中線偏移之情形，治療後，左上第二大臼齒可和左下第一大臼齒對咬，且不影響病患原本之臉型。此報告於左下第二大臼齒缺牙區植入骨釘，提供一絕對的錨定機制，將整排下顎齒列往單一方向做遠心移動，此法以骨釘方式做輔助，打破傳統矯正方法的極限，並改變傳統矯正治療計畫的設計與思路。
Non-extraction with bone screw approach was planned to distalize the lower dentition unilaterally. A 24-year-old female was presented with acceptable facial profile, and mandibular anterior crowding. The lower dental midline was shifted to the right by 4 mm and the right canines were in a cross-bite situation. Both the maxillary first premolars and left mandibular second molar had been previously extracted. The left maxillary second molar did not have any antagonist tooth. A 2.0×14 mm bone screw was placed in the lower left mandibular buccal shelf. NiTi coil spring was applied from the bone screw to the left mandibular first premolar. Sliding wire mechanic was used for distalizing the lower dentition to the left side. After unilateral diatalization of 6 months, the lower anterior crowding was relieved. The shifted lower dental midline was corrected. Maxillary second molar occludes with the mandibular first molar. The overall treatment time (leveling, distalization, finishing) was 18 months. It resulted in a full-cusp Class II molar occlusion with a Class I canine relationship. As shown in this case, bone screw provides absolute anchorage in edentulous area to move an entire dentition unilaterally. It overcomes previous limitations of conventional orthodontic tooth treatment and changes the way orthodontic treatment is planned and carried out.