| Objective: In this experiment,the T-scan digital occlusal analysis system was used to analyze the occlusal characteristics of the teeth with abnormal bite force in patients with periodontitis,and cone beam computed tomography(CBCT)was used to evaluate the height of the alveolar bone defect of the teeth.We would like to explore the distribution stability of the patients with periodontitis,to study the correlation between abnormal occlusal force and periodontal indexes,and to provide guidance for the clinical diagnosis and treatment of teeth with abnormal occlusal force in patients with periodontitis.Methods: According to the 2018 new classification of periondontitis,90 patients with periodontitis treated in the Department of Periodontics,Hospital of Stomatology,China Medical University during 2018 to 2020 were enrolled in this study.90 healthy people were also included.T-Scan Ⅲ occlusal analysis system was used to record the intercuspid occlusion and measure the relative occlusal force(ROF),bilateral force percentages(BFP),the asymmetry index of occlusal force(AOF)and the center of force(COF)position.Probing depth(PD),gingival recession(GR),sulcus bleeding index(SBI),plaque index(PLI)and clinical attachment loss(CAL)of patients with periodontitis were recorded.CBCT was used to measure the percentage of the alveolar bone defect height.SPSS 25.0 was used to statistically analyze the distribution of the above indicators in different groups,and the correlation between abnormal occlusal force and periodontal indexes.Results:1.The distribution of occlusal force between healthy subjects and patients with periodontitis in the intercuspid position:the teeth with the largest ROF in the upper mandible of both subjects was the first molar,followed by the second molar,and the teeth with the smallest ROF was the second premolar.The teeth with the largest ROF in the lower mandible of healthy subjects was the second molar,followed by the first molar and the teeth with the smallest ROF was the central incisor;among the patients,the teeth with the largest ROF was the first molar,followed by the second molar and the teeth with the smallest ROF was the central incisor.2.Bilateral force distribution of healthy subjects and patients:Regardless of healthy subjects or patients,the relative strength value(BFP)of the right side was significantly higher than that of the left side.Both healthy volunteers and patients had a certain degree of bilateral occlusal asymmetry.In patients,asymmetry index was higher than that of volunteers,which suggested that the bilateral occlusal stability in patients with periodontitis was worse than the periodontal health group.3.The distribution of the force trajectory of volunteers and patients:78 volunteers’ force trajectory were located in the gray ellipse,and 12 were outside the gray ellipse.Among the90 patients with periodontitis,only 24 patients’ force trajectories were inside the gray ellipse,and the force trajectories of remaining 66 patients were outside the gray ellipse.These results indicated that force trajectory of patients was significantly shifted.4.The distribution of teeth with abnormal biting force:Among patients,85 patients had459 teeth with abnormal force,of which 7 patients with stage Ⅱ periodontitis had 37 teeth with abnormal force,and 78 patients with stage Ⅲ periodontitis had 422 teeth.In patients,the abnormal force in upper mandible often occurs in the first molar,followed by the central and lateral incisor.The premolar area has the lowest probability of force abnormality.While the abnormal force in lower mandible often occurs in the second molar,followed by lateral incisor,and premolar had the lowest probability of force abnormalities.5.Alveolar bone defect of teeth with abnormal force in patients:In patients with stage Ⅱperiodontitis,the percentage alveolar bone height defect in incisor,canine,premolar and molar was 26.52±0.11%,27.16±0.08%,23.90±0.08% and 28.27±0.07%,respectively.In patients with stage Ⅲ periodontitis,the percentage alveolar bone height defect in incisor,canine,premolar and molar was 33.03±0.10%,33.27±0.10%,34.80±0.10% and37.60±0.13%,respectively.6.Periodontal indexes analysis of teeth with abnormal bite force in patients:In patients with periodontitis,the PD,GR,SBI,PLI of the teeth were positively correlated with ROF of this tooth.Conclusion: The first and second molars of the upper and lower jaw of healthy subjects and patients bore the main force,while the maxillary premolar area and mandibular central incisor area bore the least force.The occlusal force of each tooth in patients was higher than that of healthy subjects.Both healthy volunteers and patients had different degrees of bilateral asymmetry of force distribution,and patients had worse occlusal stability.In patients,the force trajectory was significantly shifted.In patients,abnormal bite force was most likely to occur in the molar area,followed by the incisor area,and the premolar area had the lowest probability of abnormal force.Teeth with abnormal force were accompanied by varying alveolar bone destruction. |
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