MRI study of stable splint in the treatment of unilateral anterior disc displacement without reduction with chewing side preference

XU Xin-yu; HUANG Dong-zong; WANG Yan; LIU Gang; HU Yi-fan; HU Min; LIU Hong-chen; JIANG Hua

doi:10.19749/j.cn.cjgd.1672-2973.2024.02.006

Abstract：Objective The objective of this study was to assess the effectiveness of stable occlusal splint treatment in patients with unilateral anterior disc displacement without reduction(ADDWoR)and associated unilateral mastication habits using MRI.Methods Thirty-four patients diagnosed with unilateral ADDWoR underwent clinical and imaging examinations at the Stomatology Department of the First Medical Center of the Chinese PLA General Hospital.Based on their mastication habits,patients were categorized into two groups:those with unilateral mastication(n=17)and those without(n=17).Parameters including MMO,pain index,length of the articular disc,demarcation angle,position of the articular disc,and characteristics of the lateral pterygoid muscle were analyzed.Statistical analysis was performed using SPSS 25.0 software.Results Before the treatment of stable splint,the ipsilateral disc-condylar angle of patients with CSP was higher than that of patients without CSP(51.12±17.27°),and the difference of ipsilateral and contralateral disc-condylar angle of patients with CSP was higher than that of patients without CSP(41.26±17.78°).The difference of inferior head area of ipsilateral and contralateral lateral pterygoid muscle in the group with CSP(-0.43±3.66mm2)was smaller than that in the group without CSP(0.288±4.57mm2).After treatment with stable occlusal plate,the pain and MMO were improved in both groups,and there was significant difference between the two groups(P＜0.05).There was no significant difference in pain and MMO between the two groups(P＞0.05).After the treatment of stable splint,the length of articular disc and the angle of articular disc condyle decreased between the two groups,and there was significant difference between the two groups(P＜0.05),but there was no significant difference between the two groups(P＞0.05).The average length,thickness and area of the superior and inferior pterygoid muscle were similar between the two groups after stable splint treatment,but there was no statistical difference(P＞0.05).Logistic regression analysis showed that there was a correlation between MMO(OR=0.743)and unilateral mastication.Conclusion MRI is effective for non-invasive diagnosis of ADDWoR,particularly in cases with unilateral mastication habits.Stable occlusal splint treatment significantly improves mouth opening and pain symptoms in ADDWoR patients,alleviating articular disc compression and displacement.