Nonsurgical Correction of A Severe Class III Malocclusion with Miniscrews｜【Chris Chang Ortho】CC424

Nonsurgical correction of a severe Class III malocclusion with miniscrews

Abstract

This case report describes the treatment of an 18-year-8-month old young man with skeletal Class III malocclusion. Although both dentitions were well aligned, the mandibular dental arch extruded 5mm beyond the maxillary arch and there was a diastema between maxillary central incisors. The Discrepancy Index (DI) score was 47 points. Since surgical correction was proposed and rejected by the patient, a camouflage orthodontic treatment was planned. Considering the limited retromolar space, mandibular second molars were extracted to provide space for anterior teeth retraction and avoid terminal teeth distal tipping. A passive self-ligation appliance in combination with buccal shelf mini screws and light force Class III elastics were used to correct the anterior crossbite. Vertical intermaxillary elastics were prescribed to settle the final occlusion. After 26 months of treatment, normal overjet and overbite were achieved. A pronounced improvement in smile esthetics and occlusal function was attained.

摘要

這個18歲8個月的患者有嚴重的骨性第三類錯咬合，雖然上下顎牙齒都排列得很整齊，下顎牙齒卻比上顎往前突出5mm。上顎正中門齒間有空隙。Discrepancy Index得分為47分。由於患者拒絕接受手術矯正的治療計畫，於是改採用掩飾性治療（camouflage treatment）。考量到臼齒後空間有限，治療計畫會拔除下顎第二大臼齒，合併使用自鎖式矯正器和頰棚側迷你螺絲，以及第三類橡皮筋。這樣可以提供充分的空間將下顎齒列往後拉並且避免最後一顆臼齒向後傾斜，並處理前牙錯咬問題。最後使用橡皮筋（vertical intermaxillary elastics）來穩定咬合。經過 26個月的治療，達到正常的overjet及 overbite。牙齒美觀和咬合功能皆有大幅改善。