Evaluation of the effects of temporomandibular joint arthrocentesis with hyaluronic acid injection on mandibular condyles using fractal dimension analysis: A retrospective study.

This study aimed to investigate the effects of arthrocentesis with intra-articular hyaluronic acid (HA) injection on mandibular condyles using fractal dimension (FD) analysis. Patients with temporomandibular joint (TMJ) internal derangement (ID) were divided into three groups according to how many times the arthrocentesis with HA injection was performed. FD analysis is a quantitative concept that provides information about trabecular bone microstructures. Regions of interest were selected from bone areas close to the articular surfaces of the right and left condyles on panoramic radiographs, which were taken before the procedure (T0) and at the sixth month (T1) after the procedure. Then, the FD values were calculated. All images were reviewed by the same researcher. A two-way repeated-measures analysis of variance was used to determine whether there was a significant interaction between groups, treatment sides, and time on the FD values. A total of 140 patients, including 118 patients who received bilateral arthrocentesis with HA injection and 22 control patients, were included in the study. The images of 20 randomly selected patients were re-evaluated after 2 weeks. As a result of the correlation analysis, there was no significant difference between the two measurements (P > 0.05). The main effect of time on the FD value was significant [F (1, 136) = 157.879, P < 0.001]. This effect was qualified by a significant time × group interaction effect [F (3, 136) = 18.533, P < 0.001]. The increases in the mean FD values on the right and left sides in all treatment groups between T0 and T1 times were significant (P < 0.001 for all), whereas changes in FD values on the right and left sides between T0 and T1 times were not significant in the control group (P = 0.164 and P = 0.557, respectively). After arthrocentesis with HA injections, the mean FD values increased in the mandibular condyles, depending on time in all treatment groups. Patients with TMJ ID are likely to have radiologically detectable degenerative changes and abnormalities in the condyles. The FD analysis method, which provides quantitative data, is recommended as an adjunct and guide for oral and maxillofacial surgeons in radiological examinations that should be performed together with clinical examination for the follow-up of microstructural changes in the condyle after arthrocentesis with HA injection.