Kawanami M, Andreasen J O, Borum M K, Schou S, Hjørting-Hansen E, Kato H
Department of Periodontology and Endodontology, School of Dentistry, Hokkaido University, Sapporo, Japan.
Endod Dent Traumatol. 1999 Apr;15(2):50-6. doi: 10.1111/j.1600-9657.1999.tb00752.x.
The extent of infraposition of replanted and subsequently ankylosed permanent incisors was examined in a longitudinal study of 52 patients. Study cast models were made during the follow-up period. Infraposition was evaluated on frontal photos of the study cast models taken parallel with the occlusal plane. The extent of infraposition was defined as the difference between the position of the incisal edge of the replanted incisor and the adjacent non-injured incisor in apico-coronal direction, measured with a digital caliper at 50x magnification of the negatives. The precision of this measuring procedure was 2.9% and the accuracy 2.0%. Marked infraposition was identified if the tooth was traumatized before the age of 16 in boys and before the age of 14 in girls. In addition, infraposition was observed when ankylosis developed in patients aged 20-30 years, with a yearly mean infraposition rate of 0.07 mm/year (range: 0.02-0.21 mm/year) in males and 0.07 mm/year (range: 0.00-0.12 mm/year) in females. The latter findings supported the concept of slow continuous eruption of the teeth. This phenomenon may have implications not only for the treatment of traumatized teeth but also for the treatment of tooth loss by osseointegrated implants, which represent an analogue to the ankylosed replanted tooth.
在一项对52例患者的纵向研究中，对再植并随后发生牙根粘连的恒牙切牙的下沉程度进行了检查。在随访期间制作了研究模型。根据与咬合平面平行拍摄的研究模型正面照片评估下沉情况。下沉程度定义为再植切牙切缘与相邻未受伤切牙在根尖-冠方方向的位置差异，在底片放大50倍时用数字卡尺测量。该测量程序的精度为2.9%，准确度为2.0%。如果男孩在16岁之前、女孩在14岁之前牙齿受到创伤，则确定为明显下沉。此外，在20-30岁患者发生牙根粘连时观察到下沉，男性每年平均下沉率为0.07毫米/年（范围：0.02-0.21毫米/年），女性为0.07毫米/年（范围：0.00-0.12毫米/年）。后一项发现支持了牙齿缓慢持续萌出的概念。这种现象不仅可能对创伤牙齿的治疗有影响，而且对骨结合种植体导致的牙齿缺失的治疗也有影响，骨结合种植体与牙根粘连的再植牙类似。
