A 3D reconstruction imaging study of the effect of anterior disk displacement on the bony structural relationship of the temporomandibular joint

Abstract

ABSTRACT Background: The objective of this study was to measure the association between the status of anterior disk displacement (ADD) and the alterations of the mandibular condyle and articular fossa among patients diagnosed with temporomandibular joint (TMJ) ADD. Patients and Methods: A retrospective cross sectional study was designed, dividing into 4 groups: normal articular disk position (NADP) of unilateral ADD patients (n = 10), ADD with reduction (ADDwR, n = 16), ADD without reduction (ADDwoR, n = 24), and healthy volunteers (HV, n = 30) based on magnetic resonance imaging and cone beam computed tomography. After morphological parameters were calculated from three dimensional reconstructive images, differences in parameters with respect to TMJ ADD status were tested with analysis of variance and Fisher's least significant difference multiple comparisons were performed. Results: Patients were with a female to male ratio of 6.75:1 (21 females, 4 males) and an average age of 29.10 ± 8.94 years (ranging from 16 to 51). Condylar volume (CV) of the ADDwR, ADDwoR, NADP, and HVs was 1768.29 ± 404.19 mm, 1467.13 ± 438.20 mm, 1814.48 ± 753.60 mm, and 1914.66 ± 476.48 mm, respectively, showing a significant downward trend from healthy disk to a displaced one (P < 0.05). The same trend also found in condylar superficial area (CSA), with the CSA of the ADDwR, ADDwoR, NADP, and HVs, was 842.56 ± 138.78 mm, 748.52 ± 157.42 mm, 842.87 ± 263.00 mm, and 892.73 ± 164.19 mm, respectively. From NADP to ADDwR to ADDwoR, superior joint space (SJS) was declined (SJS [NADP] [2.10 ± 0.91 mm] > SJS (ADDwR) [1.85 ± 0.61 mm] > SJS [ADDwoR] [1.50 ± 0.50 mm], P = 0.034); medial joint space (MJS) was significantly associated with the different disk displacement types (P [HV ADDwR] = 0.001; P [HV ADDwoR] = 0.021; P [NADP ADDwR] = 0.022; P [ADDwR ADDwoR] = 0.001). Conclusion: The CV and superficial area and superior and MJS are significantly associated with different disk displacement types. The mandibular condyle and articular fossa in TMJ ADD exhibited altered dimensions. These could be promising biometric markers for assessing ADD.