Nihon Shishubyo Gakkai kaishi最新文献

For the purpose of elucidating the effect of heparitinase in gingival tissue, paper strips were inserted in the gingival sulcus of a dog and were treated with heparitinase (experimental group), an enzyme-free solution (control group) or inactivated enzyme (control group) for 20 minutes once a day in order to determine the pathohistological changes in the periodontium after 3, 10 and 14 days. No marked difference was noted between the 3-day enzyme-treated group and the control groups, but for the 10-day and 14-day enzyme-treated groups, enlargement of the intercellular epithelium, neutrophil infiltration and inflammatory cellular infiltration, mainly of neutrophils, in the subepithelial connective tissue were observed. Examination of the effect of a tracer, 3H-Dextran, on the permeability of the epithelium to heparitinase revealed incorporation of 3H-Dextran by the enzyme-treated group at about 2 times as much as that by the control group, and there were more silver particles indicative of 3H-Dextran according to autoradiographic findings. Determination of the intratissue location of bacterium-derived heparitinase by the fluorescent antibody technique revealed fluorescence positivity on the gingival sulcus epithelial side but not on the oral epithelial side, and that it was more frequent in the region of the enlarged intercellular area of the upper layer of the gingival sulcus epithelium. These results suggest that bacterium-derived heparitinase present in the epithelium of the gingival sulcus of a dog lowered the defense competence peculiar to the epithelium and elevated of the permeability epithelium to bacterium-produced substances, leading to its involvement in the onset of gingival inflammation by decomposing heparan sulfate, an inter-cellular epithelial matrix.

The functional aberration of occlusion, based on the morphology of the alveolar process, causes chronic irritation of the periodontium in addition to the concomitant effect of other local environment factors. This investigation was designed to study the role of morphological characteristics in the periodontal disease process. The periodontal health of 22 subjects was recorded by clinical and roentgenological measurements of the loss of periodontal tissue. The criteria for this selection were no loss of or a crowding of adjoining teeth and no disharmony in occlusal contact. Morphological data were measured around the premolars and molars of lower jaws on the study models individuals, in bucco-lingual width of the alveolar bone in relationship to the width of the crown and the sagittal figure of the Spee curve etc. by using a three-dimensional analyzer. The subjects were categorized as Type II when the records indicated a ratio of the crown width/bone width of 1/1.2. Types I and III, depended on a greater and smaller ratio, respectively. Type W symbolized the alveolar process, of which the interproximal bone showed a considerable curvature mediodistally. Type F showed a flat pattern. The sagittal figure of the Spee curve was divided into four patterns: Pattern A or B, when the cusp of the canine and first premolar leveled over or on the occlusal plane; Pattern C, when the cusp of the canine leveled over and the first premolar under the occlusal plane, and Pattern D, when all cusps, canine, premolar and molar, were under the occlusal plane. The distance from the occlusal plane to the deepest point of the Spee curve was divided into four groups: Pattern a, when the distance was 0-1.0 mm, Pattern b, 1.1-2.0 mm, Pattern c, 2.1-3.0 mm and Pattern d, 3.1-4.0 mm. These results suggest that the morphological evaluation is a useful diagnostic indicators on a rational basis. The morphological characteristics might be related to the presence of periodontal disease and allowed to speculate the pathological changes in established stage, and also to the response to periodontal treatment in the initial stage of periodontal disease.

In vitro studies with osteoblast-like cells, revealed that in addition to preventing the immediate outflow and promoting stabilization of implant materials, these cells have the additional effect of promoting the mending and early calcification by coating the materials with collagen. The materials used for the experiment were minute hydroxyapatite, beta-tricalcium phosphate and bovine sintered bone. To these, atelocollagen which is solble in pepsin extracted from calf corium and crosslinked by using ultraviolet rays was added. We observed the cells very closely after these materials were added to alpha-modified eagle's medium containing 10 mM beta-glycero phosphate, 10% fetal bovine serum and osteoblast-like cells and the cultures incubated at 37 degrees C and 5% CO2. After 14 and 21 days, cells were fixed and stained with Alizarin Red S and Von Kossa stains to measure calcification. As a result of the collagen coating, positive areas appeared and, compared to the control improvement of the early mending was apparent. The results suggest that by coating the materials with collagen, the osteoblast-like cells show better mending and early calcification.

The purpose of this study was to evaluate the efficacy of porous hydroxyapatite (HAP) as an implant material into human periodontal defects. Thirty three patients affected by marginal periodontitis were studied. Following initial therapy, 44 periodontal osseous defects received grafts of HAP granules and blocks during flap surgery. Radiographic and various clinical examinations were performed before surgery and 1 and 2 weeks, and 1, 2, 3, 6 and more than 6 months after surgery. The results were as follows: 1. Postsurgical inflammation of the gingiva disappeared in a short time. Further more open wounds and discharges of HAP disappeared in the first month. There were no clinical problems in the sites receiving HAP implantation. 2. Radiographic demarcation lines between the implanted HAP and the surrounding alveolar bone became unclear at the beginning of bone repair. 3. At six months after surgery, the mean values of gingival recession, decrease in pocket depth and clinical attachment gain were respectively 0.9 mm, 2.7 mm, 1.9 mm. Additional observation beyond 6 months showed an attachment gain of 2.0 mm. 4. The attachment gain was less in the cases of one wall osseous defect and of furcation involvement in lower molars. These results suggest that HAP implantation is clinically effective, however, careful application is needed for the cases of one wall osseous defect or furcation involvement.

It has been unclear whether M.T.M. is acceptable for patients treated with bone grafts using hydroxyapatite (HAP), which is not biodegradable. Therefore we studied histological changes in bone among HAP during orthodontic tooth movement. HAP was implanted into artificial bone defects adjacent to second premolars in beagle dogs, and as a control no material was implanted Three months after implantation, the second premolars were moved with orthodontic force. Then they were observed histopathologically. The results obtained were as follows. The amount of movement of the teeth in implanted sites was less than in the controls. In the pressure zone, resorption of bone by osteoclasts was observed in both the implanted and the control sites, in addition, root resorption occurred adjacent to HAP. Furthermore multinucleated giant cells were closely attached to HAP and were surrounded by bone and connective tissue. In retention period there was ankylosis between the roots and bone around HAP. In the tension zone, additional bone from HAP was observed. Bone defects were filled with bone in the implanted sites, but with connective tissue in the controls. These results suggest that bone among HAP was resolved by osteoclasts. Clinically, HAP implantation for the pressure zone should be avoided because of the occurrence of root resorption and ankylosis. But for the tension zone it seems to be effective because HAP implantation produces more repaired bone.

Topical chemotherapy of periodontal disease using several drug delivery systems (DDS) is currently being attempted. PT-01 is a DDS which consists of fast- and sustained- release parts containing ofloxacin as an antibacterial agent. Since PT-01 was found to sustain the antibacterial effect for 7 days in a periodontal pocket, it was used tor periodontal patients without root planing or scaling in this study. PT-01 and a placebo were applied to two separate and opposite pockets of 46 patients, once a week from the first visit (week 0) to week 3. The clinical parameters (plaque index, gingival index, tooth mobility, bleeding on probing, pus discharge, and probing depth) were evaluated from weeks 0 to 4. At the end of the test (week 4), global improvement at the two sites was assessed. The clinical parameters and the global improvement of the PT-01 and placebo-treated sites were compared statistically. All parameters at the PT-01 sites except for tooth mobility showed much greater improvement than at the placebo sites. The global improvement of PT-01 sites was also significantly greater than that of the placebo sites. No side effects could be seen in patients treated with PT-01. These results indicate that topical chemotherapy using PT-01 could be effective and safe for periodontal therapy.

This study was performed to evaluate the efficacy of digital subtraction radiography in detecting alveolar bone changes. In order to test the sensitivity of quantitative evaluation by subtraction radiography, a copper equivalent thickness obtained from digitized radiographs was compared with the actual mineral content of bone phantoms with 15 different minerals and 25 bone specimens. Results demonstrated that the copper equivalent thickness correlated well with the actual mineral content (bone phantoms: gamma s = 1.0, bone specimens: gamma s = 0.985). In order to test the ability of digitized subtraction radiography in assessing alveolar bone changes in vivo, subtraction images were compared with histological features. The experimental angular bony defects were treated with conservative periodontal therapy in 3 monkeys. The standardized radiographs were taken longitudinally after therapy, and subtraction images were made from the sequentially obtained radiographs. In addition, for fluorescent histomorphometrical evaluations of new bone formations, the animals were dosed with oxytetracycline, calsein solution and arizarin complex solution. Radiographic and histological evaluations were scheduled to provide healing periods of 2, 3, 4, 5, 6 and 9 weeks after periodontal therapy. Subtraction radiography offered an objective method to follow histological changes of alveolar bone, and the copper equivalent thickness obtained from subtraction radiographs correlated with the histometric bone volume (gamma s = 0.9023, p less than 0.01). The results of these studies indicated that subtraction radiography was useful in monitoring alveolar bone changes associated with periodontal disease and treatment and that the quanitative measurement of periodontal bone changes by subtraction radiography was feasible.

The purpose of this study was to investigate whether plaque bacteria invade exposed radicular dentin after root planing or chemical root treatment in vitro. Pieces of dentin were cut out from impacted third molars. The surface of all dentin pieces was treated with sandpaper (#240) so as to make the surface roughness of dentin pieces equal to that of the root surface after root planing (RP surface). Half of the dentin pieces were treated with citric acid (pH 1.0) for 3 minutes (CA surface). After sterilization, each dentin piece was incubated at 37 degrees C in a culture medium inoculated with either S. mutans or S. sanguis. After 1, 3, 7 and 28 days of incubation, the invasion of microorganisms into the dentinal tubules was histologically examined using a light microscope. The following results were obtained. 1. The invasion of S. mutans and S. sanguis into the dentinal tubules was observed at 1, 3, 7 and 28 days. The depth and number of bacterial invasion into the dentinal tubules were positively correlated with incubation time on CA surfaces but not with RP surfaces. 2. The depth and the number of bacterial invasion into the dentinal tubules were higher on the CA surfaces than the RP surfaces. 3. Since the citric acid treatment of scaled and root planed root surfaces may accelerate bacterial invasion from treated root surfaces, the use of citric acid might be harmful in patients with inadequate plaque control.

Sex hormones are closely related to the onset and progression of periodontal disease. The purpose of this study was to evaluate the effects of sex hormones on the metabolism of human periodontal ligament cells. Human periodontal ligament cells and gingival fibroblasts were prepared from 7 donors with normal gingiva. 17 beta-estradiol and progesterone were purchased from Sigma Chemical Company. The effects of sex hormones on cell morphology, alkaline phosphatase activity, cell proliferation, DNA synthesis, collagen synthesis and non-collagenous protein synthesis were investigated. The results were as follows: 1. Periodontal ligament cells showed osteoinductive-like cells in the cell morphology and alkaline phosphatase activity. 2. DNA synthesis was stimulated by 17 beta-estradiol and progesterone in the presence of 5% fetal calf serum. 3. Collagen synthesis was inhibited by 17 beta-estradiol and progesterone, while non-collagenous protein synthesis was inhibited by 17 beta-estradiol and low concentrations of progesterone. 4. The addition of serum into culture medium was necessary to induce the basic metabolism of human periodontal ligament cells. It was demonstrated that sex hormones are closely related to the metabolism of human periodontal ligament cells.

The microbial flora from 46 adult periodontitis lesions of 23 patients and 18 sites in 9 healthy persons were examined and levels of serum IgG antibody to gram negative periodontal disease-associated bacteria were measured by enzyme-linked immunosorbent assay. Plaque samples and serum samples were taken 40-50 days after initial preparation consisting of scaling and root planing. To evaluate the effects of the therapy on 10 patients with adult periodontitis, changes in clinical parameters were compared with alterations of the microbial flora and serum IgG antibody levels. Black-pigmented Bacteroides species, mainly Bacteroides gingivalis, were found to be predominant in periodontitis lesions. A significant relationship was found between the prevalence of B. gingivalis and elevated titers of serum IgG antibody against the microorganism. No relationships between Bacteroides intermedius, Actinobacillus actinomycetemcomitans and elevated titers of serum IgG antibody to them were detected. The fact that there was no marked reduction of serum IgG antibody to B. gingivalis after initial preparation suggests that a more extended, longitudinal study is required. Although brushing resulted in a significant reduction of the number of total cultivable organisms in samples from periodontal pockets, no significant proportional changes in gram-negative bacteria in the lesional flora were found. Initial preparation was not effective in eliminating gram-negative bacteria from deep periodontal pockets. However, the microbiological shifts, especially the reduction in the proportion and frequency of detection of B. gingivalis in periodontal pockets, was paralleled by significant improvement in the clinical parameters.