| Objective:In this paper,the patients who reduced the vertical distance due to the severe abrasion of the posterior teeth or the loss of dentition were treated with occlusal reconstruction,the influence of the recovered vertical distance on temporomandibular joint was observed to provide reference for clinical diagnosis and treatment.Materials and methods:1.Research object:From September 2017 to September 2018,21patients,including 11 female patients and 10 male patients,aged 50～88 years with an average age of 66 years,who met the inclusion criteria were selected from the Affiliated Stomatological Hospital of Dalian Medical University.There were 4 cases of severe teeth wear,13 cases of dentition loss(9 cases of half denture loss and 4 cases of total denture loss)and 4 cases of dentition defect with severe wear of remnant teeth respectively adopting complete fixed denture,movable denture and fixed movable combined denture for occlusal reconstruction.2.Clinical examination:Including oral examination,temporomandibular joint examination,1/3 vertical distance examination under the face.3.CBCT examination of TMJ:Before and after occlusal reconstruction,Cranex D produced by Soredex of Finland was used to collect imaging information,and OnDemand3D Dental-Dental software was used for analysis.The axial plane,the sagittal plane and the coronal plane are determined by the improved method of twice marking[1].The axial plane was used to measure the internal and external diameter of the condyle,the anterior and posterior diameter of the condyle;the sagittal plane was used to measure the TMJ space;the coronal plane was used to measure the circumference,area and force angle of the condyle.The purpose of measuring TMJ space in sagittal plane was to judge the position and position change of condyle[2],and the other data was to judge the shape and shape change of condyle4.Subjective evaluation:Before and after occlusal reconstruction,patients were graded on masticatory function,comfort and aesthetic satisfaction to evaluate patients’ subjective satisfaction.Result:1.Results before occlusal reconstruction:(1)Clinical examination:①The results of intraoral examination showed 8 patients with severe teeth abration had dentin exposure and 13 patients with dentition loss had normal color,shape and texture of oral mucosa.②Clinical examination of TMJ showed that 21 patients had positive symptoms or signs of TMD(100%),21 patients had abnormal opening type(100%),5 patients had TMJ clicking(24%),10 patients had TMJ noises(48%),0 patients had TMJ pain(0%).③The 1/3 vertical distance examination under the face showed that the vertical distance of 21 patients was reduced,and the range of reduction was between 3.5 and 10 mm.(2)CBCT examination:①According to the examination of condylar bone,21 cases had abnormal cortical bone(100%),21 cases with cortical bone discontinuity(100%),12 cases with pseudocyst(57%),10 cases with abnormal shape(48%),5 cases with abnormal bone hyperplasia(24%)and 2 cases with osteophyte(10%).②The examination of the intercondylar space showed that the values of the location parameters of the condyle,LR,(posterior space-anterior space)/(posterior space+anterior space)were between±12(LR value of the left side:-0.03±0.25,LR value of the right side:-0.10±0.29),indicating that the bilateral condyles before occlusion reconstruction were located in the central area.2.Clinical examination results of TMJ after occlusal reconstruction:12 months later,compared with the results of TMJ examination before occlusal reconstruction,it was found that 100%of TMD patients showed remission of clinical manifestations,among which 6 cases(29%)of opening type returned to normal,2 cases(40%)of TMJ clicking disappeared,2 cases(20%)of TMJ noises disappeared.3.CBCT findings on TMJ condylar structure and TMJ space 12 months after occlusal reconstruction:(1)By comparing the bone condition of TMJ condyle before occlusal reconstruction,it was found that there were 17 cases of improvement of condyle bone,with a total effective rate of 81%.The area of cortical bone discontinuity disappeared in 10 cases(48%)and shrunk in 2 cases(10%);the area of pseudocyst disappeared in 4 cases(33%),shrunk in 8 cases(67%);the area of abnormal hyperplasia of condyle disappeared in 1 case(20%)and shrunk in 4 cases(80%);the shape of condyle returned to normal in 2 cases(20%);condylar osteophyte shrunk in 2 cases(100%),which proved that the occlusal reconstruction had a significant effect on the improvement of bone quality in TMD.(2)Through t-test of TMJ condylar structure data,it was found that there was a significant difference in LR value of condyle position parameters of both sides before and after occlusal reconstruction(P=0.000,P<0.05),indicating that the condyle moved in the central range after occlusal elevation;the force angle of right condyle had a significant difference before and after occlusal reconstruction(P=0.009,P<0.05),indicating that there was a difference in the angle of the cortical bone extension line on both sides of the neck in the coronal plane before and after occlusal reconstruction;there was no significant difference in the other data(P>0.05),indicating that there was basically no difference in the overall shape of the condyle before and after the repair.(3)In sagittal plane,the position of condyle and TMJ space before and after occlusal reconstruction were observed.It was found that the anterior space decreased(left side:-0.19±0.41,right side:-0.08±0.35)mm,the upper space increased(left side:0.28±0.85,right side:0.59±0.90)mm,and the posterior space increased(left side:0.43±0.45,right side:0.37 ±0.74)mm with the increase of occlusal distance(5.78±1.86)mm.The above test results showed that the difference of the anterior space was negative value,and the difference of the upper space and the posterior space was positive value,indicating that the condyle moved forward and downward after occlusal reconstruction.4.Subjective evaluation results of patients before and after occlusal reconstruction:The score of masticatory function increased from 3 to 9,and the score of comfort increased from 3 to 9,and the score of aesthetic satisfaction increased from 4 to 9,indicating that the three indicators of subjective satisfaction significantly improved.Conclusion:1.In this group of cases,the patients with short vertical distance had the positive symptoms and signs of TMD,and abnormal changes were observed in condylar cortical bone.2.Occlusal reconstruction can not only improve the clinical manifestations of TMD,but also facilitate the transformation of the diseased condyle towards the normal direction.3.In the one-year observation period,the occlusal reconstruction with fixed denture,movable denture and fixed movable combined denture can improve the temporomandibular joint structure and reduce the clinical manifestations of TMD. |
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