Clinical And Mri Imaging Evaluation Of Open Temporomandibular Joint Disc Repositioning

Objective: 1)To evaluate the clinical and MRI imaging outcomes of open temporomandibular joint disc repositioning by comparison with occlusal splint in the treatment of anterior disc displacement without reduction(ADDwo R).2)To compare the clinical and MRI imaging differences of two different disc repositioning surgeries(mini-screw anchor,[Ms A] vs opening suturing,[OSu]).3)The zebris mandibular movement analysis system was adopted to evaluate the changes of condyle and mandibular movement before and after open temporomandibular joint disc repositioning.Method: 1)Patients diagnosed with ADDwo R by MRI from June 2020 to January 2022 who underwent disc repositioning by open surgery or occlusal splint were collected and divided into occlusal splint group and disc repositioning group,Ms A and OSu group for comparison of clinical and MRI imaging effects.Before comparison,the baseline date of patients’ age,gender,unilateral and bilateral proportion,Wilkes stage,and follow-up time were matched.In the basic of consistency of baseline date,subjective visual Analog Scale of symptoms(VAS)scores were used to compare the differences in pain,diet,exercise,and quality of life(Qol)and the effective rate of improvement at 1,3,6,and 12 months before and after treatment.The difference of maximum interincisal opening(MIO),lateral excursions and protrusion distances were measured and compared.MRI was used to evaluate the changes of condylar bone remodeling(osteogenesis,stability,degeneration)and the stability of the temporomandibular disc after surgery.Independent sample t test and paired sample t test were used for statistical analysis.2)The zebris mandibular movement analysis system was used to evaluate the changes of condyle and mandibular movements before and after open joint disc repositioning,including the condyle trajectory during mouth opening and protrusion,and the paired sample t test was used for statistical analysis.Results: 305 patients were included in the study,of which 225 were treated with disc repositioning and 80 were treated with occlusal splint.1)There were 95 patients(142 sides in disc repositioning by open surgery(DROS)group,including 85 females and 10 males,with an average age of 26.0±10.4 years.There were 80 patients in the occlusal splint(OS)group(118 sides),including 71 females and 9 males,with an average age of 28.9±11.2 years.The DROS group and the OS group showed significant improvement in subjective symptom score and MIO at 3 and 6 months after treatment(p < 0.001).The subjective scores and MIO of the DROS group were further improved after 6 months compared with 3 months(p < 0.001),but there were no significant changes between 6 months and 3 months in the OS group(p > 0.05).At 3 and 6 months after treatment,the improvement degree of subjective symptoms,mouth opening and the effective rate of subjective symptom improvement were significantly better in the DROS group than in the OS group(p < 0.001).Lateral excursions and protrusion distances of the mandible decreased 3 months after surgery(p < 0.001),but returned to higher levels than before surgery 6 months after surgery(p =0.03,p=0.10).There were no significant changes in lateral excursions and protrusion distances after occlusal splint treatment(p > 0.05,p > 0.05).At 6 months after treatment,the condylar bone formation rate in the DROS group was significantly higher than that in the OS group(55.92% vs 10.17%,p < 0.001),and the bone absorption rate was significantly lower than that in the OS group(1.97% vs 15.25%,p <0.001).2)There were 77 cases(126 sides)in OSu group,including 28 females and 14 males,with an average age of 21.06±8.53 years.There were 65 patients(105 sides)in Ms A group,including 52 females and 13 males,with an average age of 24.64±13.15 years.The improvement of pain 1 month after OSu was significantly better than that after Ms A(p <0.001),and there was no significant difference in pain score 3 months after surgery between the two groups.The improvement of mandibular movement after OSu was significantly better than that after Ms A at 1 and 3 months(p < 0.001),but no significant difference was found at6 and 12 months(p>0.05).The MIO degree and lateral excursions and protrusion distances after OSu were significantly higher than those after Ms A(p < 0.05).The condylar osteogenic rate of OSu was significantly higher than that of Ms A at 12 months after surgery(68.25% vs53.33%,p = 0.020),the bone absorption rate of OSu was significantly lower than that of Ms A(p = 0.035),and the disc stability of OSu was better than that of Ms A(96.8% vs 90.5%,p =0.044).3)zebris measurements of 27 patients(45 sides)before and 3 months after open disc repositioning including 23 females and 4 males,with a mean age of 29.8±14.9 years.Although the degree of MIO increased significantly after surgery(p < 0.001),the condyle trajectory of the condylar hinge axis decreased significantly with mouth opening and mandibular protrusion.(p < 0.05)Conclusions: 1)Both open disc repositioning and occlusal splint treatment for ADDwo R can significantly improve clinical symptoms,MIO and condylar bone status,but the effect of disc repositioning treatment is better than occlusal splint treatment.2)The effect of clinical and condylar bone remodeling outcomes of OSu were superior to Ms A;3)MIO increased 3months after open disc repositioning,but the protrusion distances were limited,and the condyle movement was mainly composed of rotation.