OBJECTIVES: To compare condylar development and changes in condylar radiological appearance in patients with idiopathic condylar resorption (ICR) to a healthy, age- and gender matched, control group.

MATERIALS AND METHODS: This case-control study included 16 ICR patients [mean age: 15years, 9 months; standard deviation (SD): 4 years) and 16 controls (mean age: 16 years, 8 months; SD: 4 years, 7 months), with diagnostic (T0) and 2-year follow-up (T1) CBCT examinations. Condylar changes were evaluated through changes in condylar neck angle (CNA), and the transversal, vertical and anteroposterior displacement of five condylar points between T0 and T1. The magnitude and direction of condylar changes were evaluated using vector analyses. A qualitative radiological evaluation of the TMJ was performed based on healthy, erosive and repaired morphological appearance. Linear and angular measurements were assessed using ANOVA and a Tukey post-hoc test, and vectors were tested using an independent-sample 2-tailed t-test. Fisher's exact test was used for the qualitative evaluation.

RESULTS: At T0, ICR patients exhibited decreased condylar height, smaller condylar width and posteriorly inclined CNA compared with the control group (P < 0.05). During observation, condylar vertical growth was smaller in the ICR group than in the control group (P < 0.05). Vector analysis showed an upward direction of vertical displacement for all condylar points in the control group; the ICR group showed a downward direction (P < 0.003). The radiological appearance of 75% of the ICR condyles and 94% of the control condyles did not change during the 2-year follow-up period.

CONCLUSIONS: ICR condyles displayed reduced vertical development compared with control condyles. The radiological appearance remained unchanged for most joints. Observed changes in radiological appearance did not always follow a progressive model of degenerative joint disease.