Changes in condylar position during orthodontic treatment depending on the amount of incisor retraction: a cone-beam computed tomography study

Abstract

Abstract Objectives Orthodontic treatment may be related to temporomandibular disorders through changes in condylar position. This study aimed to evaluate changes in the condylar position during orthodontic treatment and compare those changes depending on the amount of incisal retraction using cone-beam computed tomography (CBCT) images. Materials and Methods Fifty-four participants were enrolled and divided into minimal (n = 14), moderate (n = 20), and maximal (n = 20) retraction groups according to the amount of incisor retraction (< 1, 1–6, and > 6 mm, respectively). Changes in the condylar position before (T0) and after (T1) orthodontic treatment were assessed for the superior, anterior, posterior, and medial joint spaces (SJS, AJS, PJS, and MJS, respectively). Changes in joint spaces were compared between T0 and T1 in each group using paired t-tests and among the three groups using analysis of variance. Results Anterior movement of the condyle was observed in the maximal retraction group with 0.2 mm decrease in ΔAJS and 0.2 mm increase in ΔPJS, which were significantly greater than those in the minimal retraction group. AJS and PJS showed statistically significant differences between T0 and T1 (P < 0.05) in the maximal retraction group. Conclusions The condyle may show a statistically significant but clinically insignificant forward movement in the maximal retraction group. However, it remained in an optimal position in the fossa throughout the orthodontic treatment. Clinical Relevance More attention should be paid while examining the signs and symptoms related to the condyle in patients with excessive incisal retraction during orthodontic treatment.