The same clinician (TNY) treated all the patients. The total sum of 80 teeth, the maxillary right and left, and central and lateral incisors (12, 11, 21, 22) of the 20 patients were observed radiographically Bortezomib for a period of 9 months. The exclusion criteria of the patients were: history of previous orthodontic or endodontic treatment, traumatic injuries, crown or root fractures, severely dilacerated roots, congenitally missing laterals, incomplete root formation at the start of treatment, and maxillary incisors with caries. All the periapical radiographs were obtained before the orthodontic treatment (T0), 3 (T1), 6 (T2) and 9 (T3) months after the beginning of the treatment by a paralleling device (Dentsply Rinn, Rinn Cooperation, Elgin, IL, USA), and were digitalized as 8 bit, 600 dpi with a flatbed scanner (EPSON EXPRESSION 10000 XL, Seiko Epson Co.

, Nagano, Japan) and analyzed in a software for image analysis (ImageJ 1.41o, NIH, Maryland, MD, USA) at 400x magnification in a personal computer. Mesial (a) and distal (b) incisal edge points, mesial(c) and distal (d) cementoenamel junction (CEJ) points, and mesial (e) and distal (f) edge points of the apical foramen were identified on pre-treatment and post-treatment periapical radiographs. The two points were connected by a line drawn from mesial point to distal point at the incisal, cementoenamel junction and apical levels (Figure 1). Midpoints of the drawn horizontal lines (a�Cb and e�Cf) were connected vertically. The vertical line connecting the two horizontal lines between mesial and distal edge points (a�Cb), and the cement enamel junction (c�Cd) is called ��crown height�� (A).

The vertical line connecting the two horizontal lines defined between the cementoenamel junction (c�Cd) and the apical foramen (e�Cf) is called as ��root length�� (B). The sum of ��crown height�� and ��root length�� gives the ��total tooth length.�� In this study, to measure the amount of apical root resorption, ��root length�� was used. Figure 1. a: Mesial incisal edge point, b: distal incisal edge point, c: mesial cementoenamel junction point, d: distal cementoenamel junction point, e: mesial edge point of the apical foramen, f: distal edge point of the apical foramen, A: crown height, B: root … To correct differences in projection, a defined methodology was used19 and the roots were adjusted in the following manner.

The averages of the pre-treatment and post-treatment crown lengths were computed by the following formula: Cx=(C1+C2)/2 (the average represented as Cx, pretreatment crown length represented as C1 and post-treatment crown length represented as C2). Then, the pre-treatment and post-treatment root lengths were adjusted to the averaged crown lengths. The following formula was used to adjust GSK-3 the root lengths: R1?(adjusted)=R1��(Cx/C1). The amount of root resorption was calculated as the difference between the second (post-treatment) and first (pre-treatment) root length measurements.