Nihon Shishubyo Gakkai kaishi最新文献

The present study was performed to investigate the effects of endotoxins from periodontopathic bacteria on collagen metabolism. Endotoxins were extracted from Bacteroides gingivalis 381 and Bacteroides intermedius ATCC 25611 using the hot-phenol method. A commercially available endotoxin from Escherichia coli 0111: B4 was also used as a control. Human gingival fibroblasts (Gin-1, ATCC CRL 1292) were maintained with DMEM containing 10% FBS. When the fibroblasts became confluent they were exposed to each of the endotoxins in various concentrations (0, 5, 10, 15, 20 micrograms/ml). The effects of these endotoxins on the collagen metabolism of the fibroblasts were assessed on the basis of collagen synthesis and collagenase activity. The former was assessed by 3H-proline incorporation and bacterial collagenase digestable protein. The latter was assessed by fibril assay. The results were as follows: There was no change in glucose consumption, cell viability or morphology under the light microscope when the concentration of endotoxin was 20 micrograms/ml or less. 3H-proline incorporation into protein and collagen synthesis were inclined to decrease. Endotoxin from B. gingivalis resulted in an acceleration of collagenase activity. There findings indicate that the endotoxins from these bacteria might affect collagen metabolism early in gingivitis in vivo.

A double-blind clinical study was conducted to evaluate the effect of a tartar-control dentifrice containing 1% sodium polyphosphate as tartar control agent compared with dentifrice A containing 5% sodium pyrophosphate and a placebo dentifrice. One hundred forty-eights who continued to have a degree of calculus formation after using a regular dentifrice containing no tartar control agent for 1 month in the pretest, were stratified randomly on the basis of pretest, calculus score, age and sex into 3 homogeneous groups. All subjects who received initial prophylaxis were provided the assigned dentifrice and toothbrush. No instructions regarding frequency or method of toothbrushing were allowed. Assessment of supragingival calculus was made at 4 and 12 weeks using the calculus scoring procedure proposed by Volpe et al. Side effects such as oral irritation, ablation of oral mucosa and discoloration of teeth caused by dentifrices were also diagnosed after 12 weeks of use. The following results were obtained in this study. 1. The test dentifrice had reduced (P less than 0.01) supra-gingival calculus significantly more than dentifrice A and the placebo at 12 weeks. 2. A significant reduction (P less than 0.01) was observed when dentifrice A was compared with the placebo dentifrice. 30.1% reduction was obtained using the test dentifrice and 9.0% reduction using dentifrice A when assessed in subjects who had a pretest VMI score of more than 6.0. 3. No side effects caused by the dentifrice which contained sodium polyphosphate were observed.

Clinico-histological studies were made to obtain basic data on the application of 2 piece-type hydroxyapatite (hereinafter referred to as HAP) originally designed and prepared so as to be shaped to make its clinical application easy as an anchor (HAP anchor) in the corrective movement of teeth. An immobility identification experiment and intrusive experiment were performed in order to identify absent loss of anchor to the corrective force and to identify actually practicable tooth movement by means of the HAP anchor, respectively, and clinico-histological evaluation was made of its function in both of the above cases. The results revealed no change in the distance of HAP anchor in the former experiment and tooth intrusion of 3.7 mm on average in the latter experiment and, histologically, close surrounding of almost the entire region embedded by the HAP anchor, with newly formed osseous tissues in both experiments. The above results suggest the usefulness of this trial HAP anchor as an anchor to tooth movement in periodontal therapy.

The purpose of the present investigation was to determine bacterial contamination of chlorhexidine coated and uncoated (normal) nylon filaments of toothbrushes. Ten healthy subjects were employed in this study and the test toothbrush of four lines and thirty-eight tufts were used twice a day. Test periods were 1, 8, and 20 days for each filaments of toothbrush and after they brushed the used toothbrush was kept at the constant condition (20 degrees C, 65% RH). After each test period, those toothbrushes were immediately collected and kept at the same condition for drying. After 0, 3, 6, 9, and 24 hours of drying, two tufts of filaments were pulled out from the toothbrush and cutted into two parts (end- and root-side of tufts) by sterile scissors. Each cutted part of filaments was washed with PBS and the aliquots was incubated on Brucella blood agar plate at 37 degrees C for 48 hours. The number of bacteria attached to filaments was enumerated. The results were as follows: 1. The number of bacteria attached to both end- and root-sides of chlorhexidine coated filaments decreased with the time of drying. 2. At the root-side of the normal filaments, the number of contaminated bacteria increased with the test periods. 3. The isolated bacteria from tested toothbrushes were mainly gram positive at shorter period, however, gram negative rods were also found at longer period. 4. The anti-bacterial activity of the end-side of chlorhexidine coated filaments diminished at eight days of the use, however, their activity at the root-side still remained even at twenty days. From these results, it was clear that the bacterial contamination of toothbrush was affected by several factors such as the condition of drying, the site of tufts, the using period of toothbrush and so on. To prevent this problem, it is important to keep it at good storage condition and to change it periodically. The developed chlorhexidine coated filaments of the toothbrush also indicates to be one of the useful way for prevention of bacterial contamination of toothbrush.

The purpose of this study was to examine the relationship between clinical findings and subgingival microbial flora in periodontitis. The results obtained were as follows: 1. In a phase-contrast microscopic study, no correlation was found between the clinical findings, total bacteria or proportional distribution of spirochetes or motile rods in the periodontal pocket. 2. Anaerobic incubation revealed no correlation between clinical findings, total bacteria or proportional distribution of black-pigmented Bacteroides in the periodontal pocket.

Granulated artificial bone implant materials such as hydroxyapatite (HAP) and tricalcium phosphate (TCP) have been frequently used in attempts to restore periodontal tissue lost as a result periodontitis. However, these materials are considered insufficient for the maintenance and stability of granules at sites losing bone, for active bone formation, or for periodontal ligament regeneration. We have now developed a complex consisting of HAP or TCP coated with atelocollagen (which has recently received attention as a biomaterial) and have conducted experiments to determine the effects of this material on the reconstruction of periodontal tissue. Implantations were performed using a HAP-atelocollagen complex, TCP-atelocollagen complex, HAP and TCP at three-wall bone defect sites in experimentally-induced periodontitis in dogs. A control group without the implants was included in the study. Histopathological observations were conducted 2, 4 and 12 weeks after surgery. Compared with the control group, the groups implanted with the complex displayed enhanced maintenance and stability of granules, suppression of epithelial downgrowth, and acceleration of new bone and cementum formation. These results indicate that the implant method using an atelocollagen-coated artificial bone implant material would be useful for periodontal surgical treatment, eliminating some of the disadvantages of conventional implant methods.

The purpose of this study was to compare differences in pocket reduction rate between different tooth types and sites after initial treatment. Forty-one adult periodontitis patients (mean age 40.8) whose O'Leary plaque records during initial treatment were maintained at a level of less than 10% (mean level 9.02 +/- 4.93%) were selected for this study. A total of 5983 surfaces were monitored by recording probing pocket depths (P.P.D.). The results obtained were as follows. 1. Significant probing pocket depth reduction was obtained following initial treatment (P less than 0.001). 2. Significantly improved teeth were 421/124 (p less than 0.001), 5/5 and 53/35 (p less than 0.05), and 32/23 (p less than 0.05). Deep residual P.P.D. were observed in 1/1, 6/6, 7/7, 6/6 and 7/7 (p less than 0.001), and 2/2 and 3/3 (p less than 0.05). 3. Response to treatment by tooth type was favorable in 54/45 and 431/134 and was poor in 71/17, 7/7. 4. Mandibular residual pocket depths were much deeper on proximal surfaces than on the mid-facial and lingual surfaces. Maxillary pockets on palatal surfaces were significant deeper than on facial ones. 5. Poor response to treatment was treatment was observed on the mesio-palatal surfaces (p less than 0.001), mid-palatal surfaces (p less than 0.01) of 6/6 (p less than 0.001), the distolingual surfaces of 7/7, and 7/7 (p less than 0.001), and the mesio-palatal surfaces of 1/1 (p less than 0.05). Favorable responses were observed on the disto-buccal and the id-palatal surface of 4/4 (p less than 0.05), mesio-distal buccal surfaces of 5/5 (p less than 0.05) and mesio-lingual surfaces of 4/4 (p less than 0.05). This results clearly indicate which tooth types and root surfaces must be paid careful attention to during treatment.

Cytotoxicity of povidone-iodine on cultured mammalian cells was studied using cultured Chinese hamster lung cells (V 79 cells). Treatment of V 79 cells with povidone-iodine at 100-500 micrograms/ml for 24 to 72 hr induced a growth inhibition of the cells in a dose-dependent manner. Although minimum inhibition of survival of V 79 cells was elicited in cultures treated with povidone-iodine at 100-300 micrograms/ml for 2 to 24 hr, treatment at 500 micrograms/ml for 6 to 24 hr resulted in decrease in cell survival in a treatment time-dependent fasion. Exposure of cells to povidone-iodine at 100-500 micrograms/ml for 2 hr caused inhibition of DNA, RNA or protein synthesis of cells up to 13.9% of untreated cells. These results indicate that cytotoxicity of povidone-iodine occurs in dose- and treatment time-dependent manners and that povidone-iodine induces inhibition of DNA, RNA and protein syntheses of cells, even by the treatment which causes no reduction of cell survival.

The purpose of the experiment was to study the possible penetration of extrinsic tracers with different molecular weights into exposed cementum in vitro and pathway of penetration. 75 human extracted teeth-55 periodontally diseased teeth and 20 embedded 3rd molars-were used. Each tooth was maintained in 0.005% fluorecein isothiocyanate (FITC) solution (M.W. 400), 0.05% FITC conjugated peroxidase solution (M.W. 40,000), or 0.01% FITC conjugated human IgG solution (M.W. 160,000) for 10 days. Morphological observations were made by means of fluorescence microscopy. Other extracted teeth were maintained in 0.05% microperoxidase solution (M.W. 1,900) for 5 days. Observations were then made using the TEM, and micrographs were taken and analyzed with an image analyzer. As a result, solutions of higher molecular weight showed lower penetration, and unexposed cementum showed a tendency toward greater penetration. Furthermore, the penetration of tracers on the surface of the cementum was along collagen fibers, but in the inner cementum, was into cementocyte lacunae and canaliculi.