慢性牙周炎患者之殘存齒對矯正治療施力的反應是否異於牙周正常的牙齒，目前仍少有相關研究針對此一問題加以探討。本文報告二位罹患慢性牙周炎患者在全口矯正治療後發生明顯根尖吸收情形的病例，藉以說明，慢性牙周炎患齒可能因附連喪失、齒槽骨降低改變了受力面積及旋轉中心而發生支持不足，使得原本在正常齒列中合理的施力因支撐減少而變得過當，進而使患齒發生根尖吸收。當慢性牙周炎患者接受全口矯正治療時，應於配戴矯正裝置六到九個月時進行X光檢查，一旦發現初始根尖吸收，可以用被動的主線暫停施力二到三個月，如此應可減少嚴重吸收的發生。

There are few studies discussing if orthodontic force may cause different root reaction to periodontal compromised dentition. This article reports two cases of chronic periodontitis presenting severe apical root resorption after full mouth orthodontic treatment. It indicates that periodontal compromised teeth may have their center of resistance changed because of attachment loss. The situation then makes a normal orthodontic force into abnormal because of lesser bony support. When a patient of chronic periodontitis undergo full mouth orthodontic treatment, we should reevaluate root morphology by taking periapical radiographs 6 to 8 months after the activation of orthodontic force. If it demonstrates initial root resorption, treatment should be halted for 2 to 3 months with passive archwires to reduce the possibility of severe root resorption.