Change in the Maxillary Dental Arch Dimension by Fixed Orthodontic Treatment: Well-aligned vs. Constricted Arches in Patients with Unilateral Cleft Lip and Palate

Abstract

PURPOSE: To investigate the change in the maxillary arch dimension of unilateral cleft lip and palate (UCLP) patients by fixed orthodontic treatment (FOT).

METHODS: The samples consisted of 25 UCLP patients who underwent FOT by single orthodontist. According to the shape of maxillary arch before FOT defined by Ovoid arch form template (3M Unitek), they were divided into Group 1 (well-aligned arch) and Group 2 (constricted arch). After five linear and three angular variables of the maxillary arch were measured using dental casts taken before (T1) and after FOT (T2), Wilcoxon signed rank test and Mann-Whitney U test were performed for statistical analysis.

RESULTS: At the T1 stage, Group 2 showed significantly smaller inter-second premolar width (IP2W, P<0.01), molar depth (MD, P<0.01), greater segment angle (GSA, P<0.05) and lesser segment angle (LSA, P<0.05) but larger anterior segment angle in GS (ASA-GS, P<0.05) compared to Group 1. However, at the T2 stage, there was no significant difference in all variables between the two groups. During T1-T2 stage, there was different pattern of change in variables between two groups. Group 1 showed significant increase in inter-canine width (ICW, P<0.01), IP2W (P<0.05), canine depth (CD, P<0.05), MD (P<0.05), and ASA-GS (P<0.01) except inter-molar width (IMW), GSA and LSA. However, group 2 showed significant increase in ICW (P<0.01), IP2W (P<0.001), IMW (P<0.05), CD (P<0.01), MD (P<0.01), GSA (P<0.05) and LSA (P<0.01) except ASA-GS.

CONCLUSION: According to the shape of the maxillary arch in UCLP patients at the T1 stage, different strategy can be applied to obtain forward movement of the anterior part of GS and outward rotation of LS by fixed orthodontic treatment.