CBCT And MRI Study Of Temporomandibular Joints In Adults With Sleep Bruxism

Objective: Sleep bruxism(SB)is a common oral parafunctional activity with high prevalence.Most previous studies generally support that sleep bruxism diagnosed through clinical examination and/or self-reporting is associated with temporomandibular disorders(TMD),and few studies utilize polysomnography(PSG)to diagnose SB.Magnetic resonance imaging(MRI)and cone-beam computed tomography(CBCT)have developed rapidly,and have been widely used in the examination and diagnosis of TMD.What’s more,there is still a lack of relevant knowledge about the imaging characteristics of temporomandibular joint(TMJ)soft and hard tissues in definite SB patients.Hence,this study enrolled SB patients through PSG and adopted 3.0T MRI and CBCT imaging methods to comprehensively research the imaging characteristics of TMJ soft and hard tissues of SB patients,so as to provide a theoretical basis for the clinical treatment of TMD-SB patients.Methods: All the volunteers filled out the State-Trait Anxiety Inventory(STAI)and Beck Depression Inventory-Ⅱ(BDI-Ⅱ)scales for the assessment of psychological states.Based on the Research Diagnostic Criteria for TMD(RDC/TMD),all volunteers were subjected to TMJ clinical examination.According to the diagnostic criteria of SB proposed by the American Academy of Sleep Medicine(AASM),screening potential SB patients were referred to Tianjin Medical University General Hospital for PSG.19 SB patients diagnosed by PSG(the study group)and 20 asymptomatic subjects(the control group)matched with the former’s age,gender,BMI,and education level participated in this study.MRI and CBCT images of TMJs were obtained respectively,and the shape,position of disc and joint effusion were evaluated on the MRI images,while the bone changes were analyzed on the CBCT images.The left and right TMJ of the same patient were compared by Mc Nemar test and paired t test.For qualitative data in the comparison between groups,Chi-square test was used,if ordered such as JE,Wilcoxon rank sum test was used.The quantitative data used independent sample t test,t’ test or Wilcoxon rank sum test.Results: 1.There was no statistically significant difference in STAI and BDI levels between the study group and the control group(P>0.05).2.Intra-group comparison: In the study group,the medial space(MS)and the medialhorizontal distance(M-H)of the left TMJ decreased compared with the right(P<0.05),and the lateral space(LS)increased compared with the right(P<0.05),and the rest were not statistically different(P>0.05).3.Intergroup comparison:(1)In terms of TMJ soft tissue,there was a significant difference in the incidence of disc morphology,the changes of disc position(closing position),and the grade of effusion in the study group compared with the control group(P<0.05).(2)In terms of TMJ hard tissue,the incidence of condylar bone changes in the study group was significantly higher than that in the control group(P<0.05),the proportion of the condyle flattening combined with subcortical sclerosis(13.2 %)increased,and the AS of the study group increased significantly(P<0.05).Conclusions: 1.In the coronal position,the left and right condyles of sleep bruxers were asymmetrical,and in the sagittal position,the condyles in the fossae were posterior.2.In MRI images,the abnormal performance of sleep bruxers could be characterized by convex or biplanar disc,rotational anteromedial displacement or lateral partial anterior displacement,banded or linear effusion.3.In CBCT images,the condyle bone of sleep bruxer changed,which was manifested as flattening combined with subcortical sclerosis.However,there were no significant changes in eminence and fossa in patients with sleep bruxism,suggesting that the influence of SB on TMJ bone tissue remodeling may be limited to the condyle.