Bilaterally U2-U3 Transposition in Early mixed Dentitons｜【Chris Chang Ortho】CC443 скачать в хорошем качестве

Bilaterally U2-U3 Transposition in Early mixed Dentitons｜【Chris Chang Ortho】CC443

Abstract Maxillary lateral incisor-canine transposition is extraordinarily problematic for aesthetics and function, since the lateral incisor is slimmer and shorter to bear the occlusal force and perceptive appearance of the canine. Prompting orthodontic treatment after a transposed canine has totally erupted reveals the complexity of treatment mechanics, the risk of root resorption, buccal bone recession, and serious compromises with false tooth sequence. This article discusses how to reverse the bilateral interchanges of the positions of two adjacent teeth without permanent tooth extraction, foster the arch expansion with a partially fixed appliance without bonding brackets on the lateral incisors, resulting in the maxillary canines drifting to their sequences before complete eruption. However, the expansion for increasing arch length also increased the overjet by more than 7mm. In this interceptive treatment, Class II elastics and the advanced growth of the mandible were anticipated to reduce the overjet discrepancy at the age of puberty. After three years of follow up after the treatment had been completed, the occlusion was very stable, while the overjet discrepancy never relapsed. 摘要 上顎犬齒以及側門牙錯位的問題常常會影響到美觀及咬合功能，因為側門牙與犬齒不僅在牙冠長、寬以及厚度上皆有明顯差異，而且在承受咬合力量的能力也有所不同。一旦決定在牙齒萌發完畢後才做矯正，往往需要非常複雜的矯正器及線圈組合來治療，造成患者治療期間的不適，及冗長的治療時間，同時會有牙根吸收和頰側骨吸收的問題，對牙齒長期的美觀及存活率都會有較差的期望值。所以本案例在探討牙齒錯位發生之初，也就是患者在混合齒列初期，立即給予Damon partial appliance及不在側門牙上黏矯正器，來阻止錯位的情況惡化，同時利用患者在換牙期間，牙齒自體的萌發能力，誘導錯位的犬齒回到正常的位置，期間雖然有overjet增加超過7mm以上，但利用Class II elastics和下顎自身的生長，如此大的overjet，在不用拔牙狀況下，竟戲劇化般的被改正。在治療完三年後的追蹤，咬合變得更穩定，overjet也沒有relapse發生。