dc.description.abstract | Periodontitis is the most common chronic oral disease. Periodontitis involves the periodontal tissue including gingiva, alveolar bone and periodontal ligament. Gingivitis and chronic periodontitis are frequently in clinical examination. The symptom and sign of gingivitis mostly confined to gingival tissue, gingival redness, swelling, pain, and gingival bleeding while brushing. Periodontitis the symptoms and signs of gingivitis, but the alveolar bone beneath the gingiva and periodontal ligament. There are 500-600 species of bacteria in the oral environment, existing on the tooth surface, mucosa and saliva. The bacteria species alter in different oral ecological environments. Different bacteria together a biofilm. The bacteria extracted from the periodontal pockets were mainly Gram''s negative anaerobic bacteria. Based on current literture, the periodontal disease pathogenic mechanism is caused by toxins released by the pathogenic bacteria. The toxins would evoke the gingival tissue and the host would the immune response to react. Cytokines and histodialysis enzymes are released during the process, causing alveolar bone and tissue destruction. The degree and extent of destruction depends on the defensive system function, leukocyte ability, genetic variances or environment differences, for example, inadequate oral hygiene, smoking habits, and systemic condition factors. There are 1 hundred million bacteria in 1 milligram of plaque. Inadequate oral hygiene environment increases the amount of bacteria accumulated on the tooth surface or gingival sulcus by 2 to 10 folds. Periodontal disease treatment focuses on supragingival and subgingival plaque and calculus removal. This experiment examined the adjunctive effect of photodynamic therapy on nonsurgically-treated chronic periodontitis patients. During the course of treatment, periodontal curette was applied to remove the subgingival calculus and inflammation tissue. Correct and effective oral hygiene care instructions and tooth-brushing techniques were given to the patients to reduce the amount of plaque. Clinical trial 36 patients aged between 35 to 70 years old with chronic periodontitis. At least 16 teeth in the oral cavity. Incisor, canine, or premolar teeth in the same arch on different sides were selected in pairs, and there were at least two sites with periodontal probing depth than 5mm, periodontal attachment level than 4mm as the experimental group and control group. Patients not under antibiotic medication or periodontal treatment in six month. The course of this clinical trial was arranged into two steps. In the first step, participants were all treated with scaling and root planing as full mouth periodontal nonsurgical treatment. Split mouth, the participants were into two groups experimental group then photodynamic therapy as adjunctive treatment for the nonsurgically-treated chronic periodontitis patients. And the control group injection saline as placebo for adjunctive treatment. After the photodynamic therapy and nonsurgical periodontal treatment, periodontal pocket depth, tooth mobility, and keratinized degree of gingiva were. Also, the amount of periodontal pathogenic bacteria and the amount of sulfide compound in the oral cavity were . | en |