Cocaine Abuse and Bruxism: Temporal Mandibular Joint Evaluation using FDG-PET/CT

Introduction: Cocaine abuse is associated with adverse health effects, one which includes teeth grinding, commonly known as bruxism. This can not only cause occlusal wear on teeth, but can also affect the temporal mandibular joint (TMJ) and potentially cause inflammation. For this study, we used ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) to detect inflammation of the mandibular condyle. Our aim was to assess the ability of FDG-PET/CT to discern the effects of cocaine on the TMJ and determine surrounding bone and soft tissue inflammation.

Methods: Sixty-four patients were imaged with FDG-PET/CT at a single time point and consisted of four different groups: A) HIV patients with cocaine addiction B) HIV patients without cocaine addiction C) HIV negative patients with cocaine addiction D) HIV negative patients without cocaine addiction. Osirix MD software was used to manually delineate the regions of interest (ROIs) containing the left and right TMJs. The global mean standardized uptake value (global SUVmean) was calculated in each subject as the average SUV among all voxels contained within the left and right ROIs. Inter-rater reliability was assessed by Pearson correlation. An ANOVA test, independent t-test, and Mann Whitney test were used to determine statistical significance between the independent groups.

Results: Three subjects were excluded due to imaging issues or unavailability image data. In total, 61 patients were evaluated. Excellent inter-rater reliability was observed (r = 0.997). The average global SUVmean of the four groups were: A)1.03 ± 0.27 B)1.12 ± 0.19 C)0.97 ± 0.16 D)1.06 ± 0.15. Independent t test revealed significant higher uptake in group C compared to group B (p = 0.03). Mann Whitney test also showed some statistically significant differences between groups. The same comparison between group B and C yielded a p value of 0.02. Also, non-cocaine subjects (groups B and D) had significantly higher uptake than cocaine subjects (groups A and C) (p = 0.007).

Conclusions: A reproducible method with excellent inter-rater reliability of evaluating the TMJ (within HIV positive and cocaine addicts) was found. Overall, the FDG uptake in non-cocaine subjects was statistically significantly higher than in cocaine subjects. These results contradict the hypothesis that higher FDG uptake would be found in cocaine subjects. However, the independent t test revealed that there is statistical significance between groups B and C, with group C having a higher FDG uptake.