Efficacy of clear aligner treatment in patients with cleft lip and palate: A 3-dimensional linear, angular, and morphometric study of the maxillary arch.

INTRODUCTION: This study aims to investigate the ability of clear aligners to achieve predictable outcomes in patients with cleft lip with or without cleft palate (CLP) and their effectiveness in producing symmetrical and asymmetrical changes in the maxillary arch shape. METHODS: The analysis included 48 patients with CLP who adhered to the treatment protocol. Differences between planned and achieved movements (lack of correction [LC]) after the first set of aligners were evaluated using linear and angular measurements and geometric morphometric analysis. A signed rank test for equivalence was used to test LC against clinically significant thresholds (0.5 mm for linear movements and 2° for angular movements). To analyze the arch shape, Procrustes superimposition and canonical variate analysis were applied to assess symmetrical and asymmetrical shape changes. All tests were conducted with an α error of 0.05. RESULTS: The largest planned movements were mesiodistal movements (median, 2.20 mm [interquartile range {IQR}, 1.50-4.00]) and rotations (median, 8.4° [IQR, 4.70-14.25]). The accuracy of these movements was 51.2% (IQR, 15.0-90.2) and 60.2% (IQR, 19.6-95.4), respectively. Vertical movement showed the lowest median accuracy. For most teeth and movement types, the LC exceeded the clinically significant thresholds of 0.5 mm or 2°. In the morphometric analysis, symmetrical arch shape changes were not statistically significantly different between the planned and achieved arches (T1 to T2 [P value = 0.499]), whereas asymmetrical arch shape changes were statistically significantly different between the planned and achieved arches (T1 to T2 [P value = 0.02]). CONCLUSIONS: In aligner treatment of patients with CLP, planned individual tooth movements are not fully expressed after the first set of aligners. Small symmetrical arch shape changes are predictable, whereas asymmetrical changes are unpredictable and produce side effects.