Reported here is a course of treatment and 12-year follow-up of a 63-year-old male patient with severe chronic periodontitis and type 2 diabetes. The patient presented with a chief com plaint of the mobile and swollen 7 . The blood glucose control status at the first visit was hemo globin A1c (HbA1c): 9.9, fasting blood sugar level (FBS): 140, and the mobility of 7 was Degree 3.7 was diagnosed with severe chronic periodontitis accompanied by occlusal trauma. The treat ment plan was formulated so as to first perform basic periodontal treatment along with glycemic control, aiming for preservation of the remaining teeth. Treatment progress and results: 7 was extracted as deemed hopeless. Blood glucose control remained poor, so the insulin therapy was started but in vain, and the patient was then hospitalized and periodontal treatment was inter rupted. After discharge, blood glucose control improved, but the periodontal condition of the remaining teeth gradually deteriorated, and the maxilla was fitted with a partial denture. After shifting to supportive periodontal therapy (SPT), the glycemic control was stable, but the destruc tion of the maxillary periodontal tissue continued to progress, resulting in the major decrease in the number of remaining teeth from 11 teeth at the first visit down to 2 teeth. Conclusion: Previous reports suggest that there is a correlation between effect of periodontal treatment and improvement of blood glucose levels. As in this case, however, when blood glucose control is very poor at the onset of periodontal treatment, progression of periodontal tissue destruction might continue even after improvement of the blood glucose level, in turn resulting in loss of teeth.

In occlusal reconstruction, providing uniform occlusal contact over all teeth in the intercuspal position is a necessary condition for maintaining long-term occlusal stability. From the placement of the provisional restorations and following replacement by final prostheses and onward, in addition to the conventional examination using occlusal paper every year, changes in occlusal contacts were recorded using the occlusal contact analyzer (Bite Eye^®, GC). The conventional examination showed even contacts between the left and right sides, but the occlusal contact analyzer showed some changes. In accordance with the observed minor changes, the occlusal adjustment was made to restore uniform occlusal contact. It is thought that follow-up with a highly accurate occlusal contact analyzer is beneficial for obtaining a long-term stability of occlusion and the prostheses.

[Introduction] Cuspid protected occlusion is an occlusal pattern classified based on the contact relationship between the upper and lower teeth during lateral movement, and it is defined as an occlusal pattern in which only the upper and lower canines contact and slide on the working side during lateral movement, separating the molars. It is considered that the horizontal component of mandibular eccentric movement harmful to the natural molars can be avoided by cuspid guidance and its mechanical effectiveness has been proposed, but fewer studies reported its scientific basis. In this study, using 3-dimensional finite element analysis, mechanical behaviors of the teeth and mandibular body induced by cuspid protected occlusion were investigated. [Materials and Methods] To analyze mechanical phenomena per tooth, a model of lateral loading on the molar region (analysis model 1) and mechanical behavior analysis model of the teeth and mandibular body with and without cuspid guidance (analysis model 2) were prepared from actual CT image data of a patient, input in finite element analysis software, MECHANICAL FAINDER version 9.0 (Center for Computational Mechanics Research, Tokyo), and analyzed. [Results] 1) Analysis model 1: Based on the displacement diagram, it was clarified that the teeth receive horizontal movement of the lower jaw. Large stress concentration on the cervix in the tooth and strong stress concentration on the root furcation in the alveolar bone region were observed during lateral movement compared with those in vertical loading. These were consistent with clinical symptoms, such as cervical abfraction and furcation involvement considered mechanical phenomena. 2) Analysis model 2: The stress level was high near the canine in the model with cuspid guidance and near the anterior tooth in the model without cuspid guidance. When the direction of the reaction force from the articular disc was compared, the mandibular head received the reaction force from the posterior side in the model without cuspid guidance compared with that in the model with cuspid guidance, showing that it was going to move backward.

Today temporomandibular disorder is defined as multifactorial disorder. When a patient with TMD presents with apparent occlusal abnormalities, Dentists, however, should not confine his or her intervention to the symptomatic conservative treatment in response to the patientʼs chief complaint, pretermitting the occlusal abnormalities. In order to reconstruct the occlusion by elimination of the cause of the dysfunction, to be carefully performed is a diagnosis of whether the dysfunction of the temporomandibular is related to an abnormality in the muscles of mastication or to an abnormality in the temporomandibular joint capsule, followed by reversible treatment and confirmation of remission. Presented in this report is a case of both temporomandibular joint disorder and degenerative temporomandibular disorder, as revealed by the differential diagnosis. By restoring jaw function and observing the stability of jaw movement, harmony of masticationrelated muscles was confirmed.