Evaluation of maxillary central incisors on the noncleft and cleft sides in patients with unilateral cleft lip and palate-Part 2: Relationship between root resorption, horizontal tooth movement, and quantity of grafted autogenous bone

Abstract

Objective: To evaluate the relationship between external apical root resorption (EARR) of the maxillary central incisors (U1), horizontal orthodontic tooth movement, and quantity of grafted bone in subjects with unilateral cleft lip and palate (UCLP) over an average duration of 8 years.

Materials and methods: Thirty subjects with UCLP were evaluated for EARR of U1 after edgewise treatment (T2). The teeth were classified as having no EARR, moderate EARR (combined into "no/moderate" EARR), or severe EARR. Frontal cephalometric radiographs acquired at eruption of U1 (T0), less than 6 months before secondary alveolar bone grafting (T1), and T2 were evaluated to determine the horizontal inclination (U1-axis angle) and distance of the root apex from the median line (U1-root-VL distance). On the cleft side, the quantities of grafted bone at less than 12 months postsecondary bone grafting and at T2 were evaluated using the alveolar bone graft (ABG) scale.

Results: Cleft-adjacent teeth exhibited more severe EARR than did teeth on the noncleft side. The cleft side exhibited greater changes in U1-axis angle and U1-root-VL distance between T0 and T2 than did the noncleft side. On the cleft side, the ABG score at T2 in the severe EARR group was significantly lower than that in the no/moderate EARR group. These measurements were correlated with EARR grade.

Conclusions: Cleft-adjacent U1 exhibited more severe EARR than did the U1 on the noncleft side, which might be associated with orthodontic treatment-induced changes in horizontal inclination and root apex movement. On the cleft side, severity of EARR may be correlated with the success of ABG.

Keywords: Grafted autogenous bone; Horizontal tooth movement; Root resorption of maxillary central incisors; UCLP.

Figure 1.

Evaluation of external apical root resorption using a scoring system derived from the Malmgren classification: grade 0, no root resorption; grade 1, mild resorption, root with normal length and irregular contour only; grade 2, moderate resorption with small area of root loss and root apex exhibiting an almost straight contour; grade 3, accentuated resorption with loss of almost one-third of root length; grade 4, extreme resorption with loss of more than one-third of root length.

Figure 2.

Evaluation of presurgical cleft width. White dotted line, virtual line along the major axis of the cleft; line a, line parallel to the white dotted line and touching the outermost bone of the major segment; line b, line parallel to the white dotted line and touching the outermost bone of the minor segment. Cleft width (white arrow) was measured along the line perpendicular to lines a and b.

Figure 3.

Evaluation of alveolar bone graft grade on a 4-point scale. Each root quarter was scored as follows: 0, bone present on less than half the root surface; 0.5, bone present on more than half the root surface but fails to reach the midline; and 1, bone present on more than half the root surface and extends up to the midline, as described by Witherow et al.

Figure 4.

Cephalometric analysis. A, noncleft side; B, cleft side; a, long-axis angle (°); b, U1-crown–VL distance (mm); c, U1-root–VL distance (mm); U1, maxillary incisor; VL, vertical line; HL, horizontal line; CA, central incisal axis.