We studied the mechanisms of wound healing in periodontal ligament tissue by expanded polytetrafluoroethylene (e-PTFE) membranes. Buccal mucoperiosteal flaps were elevated in the premolars of 20 dogs. The buccal bone was removed to exposethe root surface. Before elevated flaps were emplaced and sutured, membranes were adjusted to cover exposed root surfaces. No membranes were placed over root surfaces in control sites. Different dentition segments were scheduled for observation of 1, 2, 4, 6, and 8 weeks. Newly produced bone, cementum, and ankylosis were analyzed in histologic sections. Cell proliferation in regenerated tissues was studied immunohistochemically using antiproliferative cell nuclear antigen (PCNA) antibody. Alkaline phosphatase (ALP) and osteocalcin (OC) of periodontal ligament tissue grown within e-PTFE membranes were studied. One week after treatment, PCNA-positive cells were located perivascularly in the periodontal ligament close to the alveolar bone in both experimental and control groups. PCNA activity did not increase significantly in either group. After 2 weeks, periodontal ligament tissue grown within e-PTFE membranes consisted of spindle-shaped fibroblast-like cells. The exoerimented group hard warked newly formed bone and cementum, while controls had marked, new connective tissue. Alkaline phosphatase activity was localized in periodontal ligament tissue grown within e-PTFE membranes, particularly in connective tissue adjacent to newly formed bone and cementum in the experimental group. In control tissues, alkaline phosphatase activity in the connective tissue was significantly weaker than that in experimental tissues (p<0.05). After 8 weeks, OC was statistically higher (p<0.05) in tissue grown within e-PTFE membranes than in tissues grown in the absence of any ba rrier, indicating that bone was being formed.
These results suggest that periodontal ligament tissue grown within e-PTFE membranes creates an environment faloring periodontal regeneration. J Jpn Soc Periodontol, 44: 3-20, 2002.

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To analyze the change of functional movement of implants with the progression of periimplant tissue inflammation, we studied implant time-dependent displacement with vertical loading in healthy and experimental periimplant tissue inflammation.
Titanium screw implants were placed in 6 beagle dogs. Experimental periimplantitis was induced with nylon floss ligature around the implant neck. Implant displacement was measured at the baseline and each month for 6 months, after periimplantitis was induced using a laser displacement transducer under 10 g to 500 g of vertical loading. Periodontal parameters, such as probing pocket depth (PPD), probing attachment level (PAL), gingival crevicular fluid volume (Periotron ® value), tooth mobility (Periotest ® value), and X-ray assessment were measured in all subjects.
Results were as follows: 1) Vertical displacement of implants with healthy surrounding tissue was very small compared to healthy teeth. The time-dependent curve of movement of implants was completely different from that of natural teeth, indicating the presence of viscoelasticity, rather than an elastic response. 2) Severe bone resorption and soft tissue breakdown were observed after periimplantitis was induced, but the amount of implant displacement did not change significantly. 3) Once periimplantitis was induced, PPD, PAL, and Periotron increased, but the Periotest value was not statistically significant.
These results suggest that the movement of implants, which may affect function, did not change with the progression of periimplant tissue breakdown. When examining of implants, bone resorption and inflammatory response should be monitored in conjunction with mobility assessment. J Jpn Soc Periodontol, 44: 21-31, 2002.

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A patient who had severe adult periodontitis with marked destruction of the periodontal tissue advanced periodontitis with suspected mouth breathing, vertical bone defect, protrusion of the anterior maxillary teeth and teeth migration was subjected to initial preparation, such as thorough motivation, plaque control, occlusal adjustment and scaling and root planing, followed by an modified Widman flap operation. MTM was also performed to restore the dentition, occlusion, and esthetic effect. Particulary the vertical alveolar bone defect in the left mandibular molar region was repaired by an autogenous bone graft, which produced a satisfactory postoperative result in spite of its one-wall morphology. J Jpn Soc Periodontol, 44: 32-36, 2002.

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Although dentists tend to hesitate to treat pregnant patients, the initiation and progression of periodontal disease really should be controlled during pregnancy. This case report deals with an early onset periodontitis patient who became pregnant during periodontal treatment. We conducted intensive nonsurgical periodontal therapy using local drug delivery to prevent her periodontal disease from progressing while avoiding pregnancy complications such as preterm labor or preterm low birth weight.
A 34-year-old woman with severe alveolar bone loss was referred to our clinic for gingival pain and mobility of the left mandibular molars. After initial periodontal treatment, we conducted flap operations, but had to change the treatment plan to nonsurgical periodontal therapy when she entered her fourth pregnancy. Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Prevotella intermedia (Pi) were detected from many periodontal pockets by PCR analysis early on in pregnancy, and her serum IgG antibody titers to Pg, Campylobacter rectus, Treponema denticola, and Eikenella corrodens were 2 SD higher than that of healthy controls. Since gingival bleeding and tooth mobility worsened markedly despite supportive periodontal therapy, we attempted subgingival plaque control by ultrasonic scaler under irrigation with 0.002% chlorhexidine gluconate and local drug delivery using 2% minocycline hydrochloride ointment. After such periodontal treatment, Aa, Pg, and Pi were no longer detected from periodontal pockets we tested and gingival bleeding lessened. We thus succeeded in improving microflora qualitatively. We must conduct similar clinical trials to build up safer, more effective periodontal treatment for pregnant women. J Jpn Soc Periodontol, 44: 37-45, 2002.

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Ozone is strong oxidative gas used for sterilization, e. g., in the treatment of peripheral blood circulation disease and sores and viral infections. The aim of this study was to investigate the influence of ozone treatment on the cells derived from human periodontium, periodontopathic and subgingival plaque bacteria. The cytotoxic effect of ozone was evaluated by fluorescein diacetate (FDA) -propidium iodide (PI) double-staining to the confluent condition cells. The influence on suspended cells was evaluated by adherent cell number, in which cells were cultured for 6 hours after treatment with ozonized water. The bactericidal effect was evaluated by counting the number of viable bacteria (CFU/ml) after treatment with ozonized water. The cytotoxicity was slight in confluent cells and marked in suspended cells. Dulbecco's modified Eagle's medium (DMEM) supplemented with 5% fetal calf serum also decreased ozone cytotoxicity in cells. These results show that ozone action is influenced by environmental factors, including serum in DMEM and extracellular matrix. The bactericidal effect was marked in periodontopathic bacteria and, depending upon the ozone concentration, in microbiota in subgingival plaque, including food debris and bacterial products, suggesting that applying ozonized water in periodontal treatment is beneficial. J Jpn Soc Periodontol, 44 : 46-54, 2002.

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We studied the differentiation of osteoblast precursor cells into osteoblasts and how this relates to the expression of noncollagenous proteins (NCPs), osteonectin (ON), bone sialoprotein (BSP), osteocalcin (OC), decorin, biglycan, and osteopontin (OPN) early in the formation of bone in the rat mandible by alkaline phosphatase (ALP) enzyme histochemistry and in situ hybridization. Mandibles of rat fetuses were collected on embryonic days 13.0 (E13.0) to E 15.0. Meckel's cartilage anlage and osteoblast precursor cells showing ALP activity appeared first at E 13.5 closely associated with nerve fibers in the developing mandible. Further differentiation in anlage was accompanied by increased expression of glycosaminoglycans and resulted in the formation of Meckel's cartilage. Osteoblast differentiation increased as the number of osteoblast precursor cells and their ALP activity increased in specimens from E 14.0 to E 15.0. At E 15, all NCPs were expressed by these ALP-positive cells, but their expression patterns differed: expression of NCPs other than OPN was observed in the majority of osteoblasts, which expressed ON and BSP intensely and OC, decorin, and biglycan weakly, whereas OPN was expressed intensely by only a few osteoblasts. These results indicate that the appearance of osteoblast precursor cells showing ALP activity is temporally and spatially related to that of Meckel's cartilage anlage and nerve fibers and precursor cells differentiate into osteoblasts at varying stages of differentiation at E 15. J Jpn Soc Periodontol, 44: 55-63, 2002.

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We studied Japanese patients with periodontal disease to epidemiologically evaluate the possible relationship between diabetic conditions and oral findings. Subjects, all of whom providedinformed consent, were 601 men and women 30-69 years old (mean: ± S.D. : 54.3 ± 9.0). All were treated atdental offices in Aichi Prefecture and all had 1 or more sites with a probing pocket depth (PPD) of 5 mm or more. Subjects were divided into 3 groups based on diagnosis of diabetes mellitus.—group D, those with diabetes; group I, those with impaired glucose tolerance; and group N, those with normal glucose tolerance.—to compare difference in oral findings between diabetic and nondiabetic groups. Groups D and I were analyzed further to evaluate the correlation between oral findings and fasting plasma glucose (FPG) or medical treatment of diabetes. When we compared groups D and N, dental and periodontal conditions were worse in group D. We found in groups D and I that no significant correlation existed between FPG and oral findings, such as mean teeth number, mean PPD and other periodontal conditions. When groups D and I were divided into 3 based on medical treatment of diabetes.—group DE, diet control and/or physical exercise only; group DR, administration of oral hypoglycemic drugs; and group IN, insulin injection.—, the mean PPD was less in groups DR and IN than in group DE, whether FPG was high or low (p<0.01). The same trend was seen in teeth mobility, indicating that medical treatment of diabetes using insulin or oral hypoglycemic drugs may affect the reduction of periodontal tissue destruction caused by periodontal disease. J Jpn Soc Periodontol, 44: 64-72, 2002.

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Biochemical markers in gingival crevicular fluid (GCF) have been studied to precisely and objectively diagnose periodontal disease. Carboxy terminal propeptide of type I procollagen (P1 CP) and osteocalcin (OCN) are bone-related proteins produced by osteoblasts that are useful clinical indicators of metabolic bone diseases such as osteoporosis and hyperparathyroidism. To determine bone-related markers in GCF, we studied the presence of P1 CP and OCN in GCF from periodontitis patients using immunoenzymatic kits and the relationship between P1 CP/OCN amounts and clinical parameters involving gingival index (GI), probing depth (PD), and bleeding on probing (BOP). GCF samples were collected with paperstrips from 70 diseased sites (PD>4 mm) in 70 periodontitis patients and from 30 healthy sites (PD<3 mm) in 30 healthy volunteers. A mean of 1.04 ng/site (0.91 ng/μl) P1 CP was found at diseased sites and a mean of 0.17 ng/site (0.38 ng/μl) at healthy sites, showing a 6.1-fold amount of P1 CP at diseased sites. A mean of 56.3 pg/site (47.6 pg/μl) OCN was found at diseased sites and a mean of 38.8 pg/site (123.9 pg/μl) at healthy sites, showing a 1.5-fold amount of OCN at diseased sites. Both P1 CP and OCN in GCF correlated positively with GI and PD, especially P1 CP, P1 CP greatly increased at BOP-positive sites (5.5-fold), suggesting that P1 CP may reflect disease activity in alveolar bone metabolism. These results indicate that P1 CP and OCN are present in GCF and that these molecules may be useful as a bonerelated marker in periodontitis. P1 CP may prove to be an especially potent marker for bone turnover in periodontitis. J Jpn Soc Periodontol, 44: 73-81, 2002.

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Laser treatment is widely used in dental practice, e. g., in the removal ofmelanin pigentation in oral mucosa.
We conducted 2 pigmentation removal therapies simultaneously on the same patients, i. e., Er: YAG laser (Er-L) and conventional phenol-alcohol (PA), and compared treatment effects to evaluate the effectiveness of dental laser therapy in removing melanin pigmentation.
Subjects were 5 men aged 26 to 33 years (mean: 28±2.5) who gave prior informed consent. Treated were the anterior maxillae. Upper right anterior underwent received Er-L therapy and upper left anterior regions PA therapy.
The Er: YAG laser Erwin (Morita, Japan) was used in Er-L following the manufacturer's instructions. In PA, 90% phenol was applied with a cotton pellet and maintained for 30 seconds, followed by 30-second neutralization with 99% alcohol and sufficient rinsing.
Clinical photographs were converted to 256-gradation digital data with a personal computer. The results of melanin pigmentation removal were evaluated at baseline, 2 weeks, and 24 weeks, using density as an index. In all subjects, both therapies showed inproved pigmentation removal. The effect of Er-L was not remarkable. These results, suggest that although Er-L produces some improvement in melanin pigmentation in gingiva, its effect is less significant than that of PA. Because Er: YAG laser, due to its short oscillation wavelength 2.94 μm, reacts with moisture on the surface of living tissues and is less likey to reach melanin pigmentation sites in a deeper layer. In the application of Er-L in the removal of melanin pigmention, further study appears necessary on the number of treatment sessions, laser radiation power, and other factors. J Jpn Soc Periodontol, 44: 82-87, 2002.

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