Incidence of degenerative disease of the temporomandibular joint in anterior open bite patients with different molar relationships: a retrospective CBCT study

Abstract

Abstract Objectives To assess the prevalence of degenerative joint disease (DJD) in anterior open bite (AOB) patients with different molar relationships. Methods 246 AOB adult orthodontic patients were divided into Class I group (n = 65), Class II group (n = 116) and Class III group (n = 65) based on their sagittal molar relationships, meanwhile, 70 normal subjects were selected as control group. The morphological characteristics of temporomandibular joint (TMJ) and occurrence of DJD in the subjects were detected by cone-beam computed tomography, and the incidence of DJD among them was compared. Mandibular plane angle and the vertical distance between the upper and lower incisors (ULD) were also measured. Results The overall incidence of DJD in AOB patients and control group was 30.28% and 5.00%, respectively. Class II group showed a significantly highest incidence of DJD (50.43%, P<0.001), highest frequency of bilateral DJD (43.95%, P<0.001) and highest mandibular plane angle (MP-SN of 44.39°±7.02° and MP-FH of 35.68° ± 6.74°,P<0.001). Among the AOB groups, Class III group exhibited the highest ULD (3.35 ± 1.86mm, P<0.05) but the lowest incidence of DJD (10.77%). Conclusions AOB patients with Class II molar relationship exhibit the highest incidence of DJD, and orthodontists should pay closer attention to the risk of temporomandibular joint diseases (TMD) in Class II AOB patients during clinical practice.