Skeletal Class III malocclusion treatment using mandibular and maxillary skeletal anchorage and intermaxillary elastics: a case report

ABSTRACT Introduction: Skeletal Class III malocclusion is one of the most challenging malocclusions to treat. In around 40% of Class III patients, maxillary retrognathia is the main cause of the problem and in most patients, orthopedic/surgical treatments includes some type of maxillary protraction. Objective: The aim of this case report was to describe a treatment method for a patient with maxillary retrognathia and Class III skeletal discrepancy using mandibular and maxillary skeletal anchorage with intermaxillary elastics. Case report: A 13-year-old boy with maxillary retrognathia and mandibular prognathism was treated using bilateral miniplates. Two miniplates were inserted in the mandibular canine area and two other miniplates were placed in the infrazygomatic crests of the maxilla. Class III intermaxillary elastics were used between the miniplates. Results: After eight months of orthopedic therapy, ANB angle increased by 4.1 degrees and ideal overjet and overbite were achieved. Mandibular plane angle was increased by 2.1 degrees and the palatal plane was rotated counterclockwise by 4.8 degrees. Conclusion: This case showed that the skeletal anchorage treatment method may be a viable option for treating patients with Class III skeletal malocclusion.

摘要
引言：骨性III类错（牙合）（Skeletal Class III malocclusion）是治疗难度最高的错（牙合）畸形之一。约40%的III类错（牙合）患者以上颌后缩（maxillary retrognathia）为主要致病因素，多数患者的正畸-正颌治疗（orthopedic/surgical treatments）会采用某种形式的上颌前牵（maxillary protraction）。
目的：本病例报告旨在介绍一种针对上颌后缩合并骨性III类骨骼畸形（Class III skeletal discrepancy）患者的治疗方案，该方案采用上下颌坚固支抗（skeletal anchorage）配合颌间弹力牵引（intermaxillary elastics）。
病例报告：1例13岁男性上颌后缩合并下颌前突（mandibular prognathism）患者接受了双侧微型种植板（miniplates）辅助治疗。于下颌尖牙区植入2枚微型种植板，在上颌骨颧下嵴（infrazygomatic crests）处植入另外2枚微型种植板，并于种植板之间施加III类颌间弹力牵引。
结果：经过8个月的正畸矫治后，ANB角（ANB angle）增加了4.1°，获得了理想的覆盖（overjet）与覆（牙合）（overbite）。下颌平面角（mandibular plane angle）增加了2.1°，腭平面（palatal plane）逆时针旋转了4.8°。
结论：本病例表明，坚固支抗治疗方案可作为骨性III类错（牙合）患者的可行治疗选择。