The main purpose of periodontal therapy is to maintain natural dentition and functional periodontal apparatus for a lifetime by creating an easy oral environment for patients' oral hygiene. The resective surgical approach and mucogingival surgery (MGS) were major periodontal therapies in periodontics until the 1970's. However, the problems of aesthetics, root sensitivity and root caries resulting from resective therapy for severe periodontitis were eventually pointed out. Also the healing of resective therapy was admitted to be "Repair" not "Regeneration" after evaluations of animal and human studies. Since then, a variety of periodontal tissue regenerative techniques and devices were developed. Guided tissue regeneration (GTR) utilizing the barrier membrane was advocated by S. Nyman et al. as a new treatment approach for periodontal tissue regeneration in the 1980's. In the 1990's, EMD (Emdogain) was developed as the biological regeneration approach and has been utilized for regenerative therapy. EMD seems to mimic the development of the attachment apparatus during nascent tooth development. Alveolar bone formation is induced de novo by EMD and/or triggered by early cementum formation. The regenerative potential of EMD in intrabony defects is at least equal to or better than other "regenerative" therapies based on clinical parameters. Recently, making use of growth factor, such as BMP or PDGF, in periodontal tissue regenerative therapy has been attempted. In particula PRP (Platelet Rich Plasma) including various cytokines is in actual clinical use for periodontal regenerative therapy. This presentation concluded by surveying periodontal regenerative therapy from the past to the future in conjunction with my clinical experience.

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The purpose of this study was to evaluate differences in tongue movement function between young and elderly subjects. We developed a tongue-movement measuring device and which was used with 3 young subjects and 3 elderly subjects to measure the duration of two types of tasks (anteroposterior and lateral movements). In both movements, the duration measured for elderly subjects proved to be longer than that for young subjects. In both groups, the duration of the first trial of each task was longer than that of the second or the third trial. These results suggested that tongue movement functionality for elderly subjects was lower than that for young subjects, and tongue movement function was improved by repeating the same task.

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The purpose of this study was to elucidate the determinant essentials of maxillary dental arch form by studying morphological characteristics of 62 maxillary dental arches using Fourier analysis. Fourier analysis was conducted on the polar coordinate system developed from the vectors. Fourier coefficients and amplitudes were analyzed for evaluation of maxillary dental arch forms. The results showed that 1) Each maxillary dental arch form was reproduced by the 1^<st> to the 4^<th> of the Fourier harmonics. 2) The constant value of the Fourier series showed a positive relationship with the width of the dental arch, and also the amplitude of the 1st Fourier harmonic had a positive correlation with the length of the dental arch. 3) The amplitudes of the 2^<nd>, 3^<rd>, and 4^<th> Fourier harmonics were shown to closely correlate with length/width ratio, the curvature of anterior teeth and the curvilinear contour of the dental arch. In the present study, we demonstrate that maxillary dental arch forms consist of three components : length/width ratio, the curvature of anterior teeth, and the curvilinear contour of the dental arches, and the length/width ratio is the most informative of the three components.

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Actinobacillus actinomycetemcomitans, an oral bacterium implicated in the etiology of periodontal and systemic diseases, produces cytolethal distending toxin (CDT) that induces G_2/M cell cycle arrest followed by cell death. To investigate the possible role of CDT in the induction of monocyte apoptosis, I analysed the molecular mechanisms involved in the apoptotic pathway purified recombinant CDT in human monocytic U937 cells treated with purified recombinant CDT. Treatment with CDT caused cellular distension and condensation of nuclei after 24h. Flow cytometry analysis revealed that U937 cells treated with CDT were arrested in the G_2/M phase of the cell cycle after 18h, followed by DNA fragmentation and breakdown of the cell membrane after 24h. It is well known that the degradation of lamin A/C occurs during apoptosis. In the present study, a found that the degradation of lamin A/C was observed after 24h of CDT treatment, and that the degradation was significantly reduced by an inhibitor of caspase-6, partially reduced by an inhibitor of caspase-9, but not affected by an inhibitor of caspase-3/7/8. In contrast, caspase inhibitors suppressed DNA fragmentation, but had no effect on the G_2/M arrest of CDT-treated U937 cells. These results suggest the importance of the apoptotic pathway in lamin degradation through the activation of caspases in CDT-induced apoptosis of human monocytes.

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Orthognathic surgical treatment has been provided for many patients with skeletal Class III malocclusion in order to correct deviated dentofacial morphology and to improve the impeded oro-facial function. In this study, we investigated the relationship between dentofacial morphology and mandibular movement in subjects with skeletal Class III malocclusion, while they were chewing gum. The subjects were 16 patients with skeletal Class III malocclusion scheduled to undergo orthognathic surgical treatment (jaw deformity group) and 21 with normal occlusion (normal group). In the jaw deformity group, records taken before treatment and at 1-6 months after completion of active treatment were used for this study. The dentofacial morphology was analyzed using lateral roentgen cephalograms. The mandibular movement was recorded by tracing the incisal point (the midpoint between mandibular central incisors) while chewing gum using the integrated jaw function testing system (gnathohexagraph system, JM-1000, Ono Sokki Tokyo, Japan). The following results were obtained. 1. The mean duration of a chewing cycle was significantly longer in the jaw deformity group than in the normal group. 2. After treatment, the mean duration got shorter and approached that in the normal group. 3. The maximal distance of mouth opening was larger in the jaw deformity group, and decreased after treatment. 4. The speed of mandibular movement showed no significant difference between the jaw deformity and normal groups, nor between before and after treatment in the jaw deformity group. 5. The variability of masticatory rhythm was significantly higher in the jaw deformity group as compared with that in the normal group. However, it got lower after treatment, and showed no significant difference in comparison with the normal group. Based on these findings, it is suggested that orthognathic surgical treatment for skeletal Class III malocclusion corrects imbalanced dentofacial morphology and improves impeded masticatory movement.

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