The aim of this study was to determine the presence of condylar spatial changes in patients having rapid maxillary expansion treatments compared to a control group.

Thirty-seven patients with maxillary transverse deficiency (11–17 years old) were randomly allocated into two groups (one treatment group – tooth borne expander [hyrax] – and one control group). Cone-beam computer tomographies (CBCT) were obtained from each patient at two time points (initial T₁ and at removal of appliance at 6 months T₂). CBCTs were analyzed using AVIZO software and landmarks were placed on the upper first molars and premolars, cranial base, condyles and glenoid fossa. Descriptive statistics, intraclass correlation coefficients and one-way Anova analysis were used to determine if there was a change in condyle position with respect to the glenoid fossa and cranial base and if there was a statistically significant difference between groups.

Descriptive statistics show that changes in the condyle position with respect to the glenoid fossa were minor in both groups (<1.9mm average for both groups). The largest difference in both groups was found when measuring the distance between the left and right condyle heads. When comparing changes between both groups, no statistically significant difference was found between changes in the condyles (P<0.05).

Rapid maxillary expansion treatments present mild effects/changes on the condylar position. Nevertheless, these changes do not present a significant difference with controls, thus not constituting a limitation for applying this treatment.