Quantitative and qualitative condylar changes Post-Stabilization splint in patients with temporomandibular disorder and chewing side preference

This study aimed to explore the quantitative (joint spaces, condylar position, morphology, and fossa) and qualitative (bone mineral density (BMD), condylar volume (CV), and condylar surface area (CSA)) therapeutic outcomes following a stabilization splint (S.S.) therapy in adult patients diagnosed with temporomandibular disorder (TMD) (Arthralgia) with/without chewing side preference (CSP) using cone-beam computed tomography (CBCT). This retrospective study included 64 patients divided into two groups: 32 with TMD + CSP and 32 with TMD only. TMD was diagnosed using the Diagnostic Criteria for TMD (DC/TMD) AXIS I. The Observed Preferred Chewing Side (OPCS) and State Preferred Chewing Side (SPCS) methods assessed CSP status. CBCT scanned the temporomandibular joint (TMJ) before (T0) and after (T1) treatment for three-dimensional (3D) analysis. Statistical comparisons were made using the Wilcoxon signed ranks and Mann-Whitney U tests. The treatment duration ranged from 6 to 12 months, with an average of 9.5 months. In the TMD + CSP group, significant differences were observed between pre-treatment (T0) and post-treatment (T1) for joint space measures, including (SJS, PJS, and CLS) on the preferred side (p-value = 0.04; 0.00; 0.02, respectively), with significant differences for the balancing side in (SJS, PJS, and CMS) (p-value = 0.01; 0.03; 0.016 respectively). The TMD group showed significant changes in (AJS) on both symptomatic and contralateral sides (p-value = 0.015; 0.01 respectively). Morphologically, significant differences were noted in condyle width (CL2) in the TMD + CSP group on the preferred side between T0 and T1, along with significant differences in intra-group comparison in fossa height (FH), fossa width (FW), and articular eminence (θ) at T0, with FW and θ remaining significant at T1 (p-value = 0.01; 0.02; 0.01; 0.00, and 0.04 respectively). The TMD group exhibited significant changes in condylar length (CL1) on both sides between T0 and T1 (p-value = 0.03; 0.01 respectively). Qualitatively, BMD disturbance was significant in the TMD + CSP on the preferred side group across the majority of slopes when compared to the balancing side between T0 and T1 and for intragroup comparison at T0 and T1, while in TMD group showed changes on the symptomatic side in (AS) only when compared to the contralateral side between T0 and T1and for intragroup comparison at T0 (p-value = 0.035; 0.045; and 0.01 respectively). Additionally, significant differences in CV and CSA were observed in the TMD + CSP group on the preferred side between T0 and T1 (p-value = 0.04; 0.03 respectively), with intra-group comparisons highlighting significant differences in both CV and CSA at T0 and T1 (p-value = 0.01; 0.02; < 0.001; 0.03, respectively). The co-occurrence of TMD + CSP exacerbates TMD severity and affects both quantitative and qualitative measures. This condition leads to asymmetrical condylar positions, distinct morphological changes, and imbalance in BMD, increasing the risk of degenerative changes over time.