Evaluation of 99mTc Uptake in the Mandibular Condyle, Comparison Between the Two Sides, and Correlation with the First Cervical Vertebra in Patients with Mandibular Deviation

Introduction: This pilot study aimed to evaluate the uptake of the radiopharmaceutical 99mTc in the mandibular condyles and cervical vertebrae on bone scintigraphy and to assess the correlation between inter-condylar metabolic disparities and longitudinal soft-tissue changes in patients presenting with progressive mandibular deviation. Materials and Methods: This prospective longitudinal pilot study enrolled patients referred to orthodontic and oral and maxillofacial surgery clinics with suspected condylar hyperactivity and mandibular deviation. Bone scintigraphy was performed at baseline to assess 99mTc-MDP uptake in both mandibular condyles normalized against the first cervical vertebra (C1). Standardized facial photographs were obtained at baseline and after a 6-month prospective follow-up period to evaluate soft-tissue asymmetry changes. Results: Over the 6-month observation period, the most pronounced soft-tissue variations were observed in An.b (mean: 62.40 ± 33.69) and Gn.a (mean: 38.59 ± 34.41). Bivariate Pearson correlation analysis revealed a statistically significant, strong negative correlation between inter-condylar 99mTc uptake differences (L−R) and changes in pog.oc (r = -0.821, 95% CI: [-0.96, -0.26], p = 0.012). Non-significant moderate-to-strong correlations with inter-condylar uptake differences were noted for Gn.b (r = -0.643, p = 0.086), ph.b (r = 0.607, p = 0.110), and pog.b (r = 0.571, p = 0.139). Conclusion: Preliminary findings suggest that quantitative 99m Tc bone scintigraphy demonstrated preliminary correlations with specific regional soft-tissue changes. Given the small sample size and lack of diagnostic validation against a reference standard, these findings reflect exploratory associations rather than predictive capability. Larger prospective studies are required to clarify the clinical utility of semi-quantitative scintigraphy in asymmetry management.