Nihon Shishubyo Gakkai kaishi最新文献

Since endotoxin may be absorbed only in the superficial layer of cementum leaving the deep cementum unchanged morphologically, the cementum of teeth with periodontal involvement was examined. The author considered that the application of citric acid after curetting of only the superficial cementum was better root treatment than complete removal of the cementum. The aim of this study was to examine histological events during the formation of new fibrous attachment to demineralized cementum after flap surgery following citric acid treatment in fifteen dogs. The demineralized cementum prevented the apical proliferation of junctional epithelium. The fibroblasts apposed to the exposed cemental collagen produced numerous new fibrils. Furthermore, the newly-formed collagen fibrils appeared to link with the exposed ones. These findings suggest that this root treatment would facilitate the formation of new fibrous attachment.

The purpose of this study is to examine the relation ship between residual plaque score at an individual tooth surface during initial treatment and the pocket reduction rate at the evaluation time. Thirty-nine adult periodontal patients (mean age 30.2 years) who O'Leary plaque control record (PCR) reached a level of 10% PCR, were selected for this study. A total of 5638 surfaces were monitored by recording probing pocket depths at the disto-buccal (a), mid-buccal (b), mesio-buccal (c), disto-lingual (d), mid-lingual and (e), mesio-lingual (f) regions, and by examining O'Leary plaque control records. The results were as follows: 1) The residual plaque score at all teeth surfaces was 14.74 +/- 19.21%. 2) The lowest plaque score were seen at 54/45, and 21/12. 3) The highest plaque score were seen at 7/7, and 76/67. 4) Well-responding sites that showed a high residual plaque score and a good pocket reduction rate, were 5/5 (initial probing pocket depth 3.0-3.5mm, a), and 4/4 (initial probing pocket depth 3.0-3.5 mm,f; 5.0-5.5 mm, f). 5) 7/7 (initial probing pocket depth 3.0 mm a, b, d), and 7/7 (initial probing pocket depth 3.0-3.5 mm, f) showed a high residual plaque score and a low pocket reduction rate. 6) The normal pocket response occurred at a level of residual plaque score and a low pocket reduction rate. 6) The normal pocket response occurred at a level of residual plaque score of less than 25%. In order to gain good pocket response, it is important to keep the level of residual plaque score at less than 25% rather than to keep the level of PCR at 10% or 20% (as several authors have previously stated). 7) A low residual plaque score during treatment is therefore more important than a low PCR.

In order to assess by periodontal evaluation the changes that might occur with time in the abutment teeth and periodontal tissues when Konus-Telescope dentures are used as that final treatment of periodontal disease, the dentures (15 units) were placed in 13 patients with missing tooth and periodontal disease and findings at the time of denture placement and 30 months after the placement were compared. The number of cases that exhibited significant changes in hygiene level, tissue inflammation and periodontal pocket depth of the abutment teeth after 30 months was very small, while as many as 85.2% of the abutment teeth showed decrease in tooth mobility. Increase in tooth mobility was not detected in any of the cases. In addition, X-ray examination revealed tendencies toward improvement of the periodontal ligament and remission of alveolar bone resorption in many of the cases. These results suggest that Konus-Telescope denture is highly offers protection of the residual periodontal tissues through its secondary splint action.

Interleukin-6 (IL-6) is involved in the final differentiation of B cells into antibody-producing cells. Recent studies reveal that IL-6 plays an important role in inflammation. Histopathological studies showed that a large number of plasma cells in periodontitis is usually seen in the apical parts of cellular infiltrates beneath the periodontal connective tissues. This evidence suggests that IL-6 may play a critical role in the development of periodontitis. Therefore, we examined IL-6 production in the gingival tissues. Twelve periodontitis patients and five gingivitis patients were included in this study. Nine individuals with healthy periodontium acted as control subjects. Biopsy specimens were dissected into fragments 3 mm in diameter and plated onto 24-well culture plates with RPMI 1640 medium. IL-6 activity in the culture supernatants was measured by IgM production assay using the cell line SKW6-CL4. IL-6 activity was detected at significantly higher levels (P less than 0.001) in culture supernatants from the gingival tissues in periodontitis (23.2 +/- 14.4 units/ml) and gingivititis (12.5 +/- 3.4 units/ml) than in control tissues (2.3 +/- 1.2 units/ml). Subsequently, the relationship between IL-6 activity and clinical stages was examined. The IL-6 levels before initial preparation (23.2 +/- 14.4 units/ml) were significantly higher (P less than 0.001) than those after initial preparation (1.4 +/- 1.8 units/ml), but were not associated with either periodontal pocket depth or the extent of alveolar bone resorption in periodontitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Damage to periodontal tissues caused by dental materials (silver alloy powder) was examined by histopathological observation. Three kinds of silver alloy powder containing copper of various contents, such as that used in the first group: Ag-Cu (25% Cu), second group: Ag-In (5% Cu), and third group: Ag-Sn-Zn (0% Cu), were used to analyze damage to periodontal tissues caused by silver alloy powder. With No. 1/2 round bar, standardized small cavities were prepared in the mesiolingual cervical portion of the upper first molars of rats. Three kinds of silver alloy powder were then inserted into the small cavities. Postoperative changes in the gingival tissues were studied histopathologically. The results were as follows: 1. Under the light microscope, all three groups showed similar tissue reaction. Many dark deposit (metal) were observed in the lamina propria of the gingiva. These dark deposits had been taken into the histiocyte-like cells and multinucleate giant cells. Infiltration of cells was not observed around these dark deposits. Findings among the metals in three groups were of specific structures, which displayed black and dark-brown stained deposits in surrounding silver alloy powder. 2. Under the electron microscope, the first, second and third groups showed similar tissue reactions. Dark deposits (metal) had been taken into the multinucleate giant cells. These cells contained many lysosomes, vacuoles, and endocytosed materials. The deposits consisted of a dence central core of silver alloy powder surrounded by fine needle-like components and filaments of lower electron density. Extremely fine particles were also observed around the basal lamina of capillary vessels and along collagen fibers. 3. By AEM, components of the lower electron density material were identified as silver, copper and sulfur in the first and second group, and silver and sulfur in the third group. The elements in the fine particles were silver and sulfur. 4. Using scanning electron microscope, the micrograph indicated that a barnacle-like structure was formed on the surface of the silver alloy in the gingival tissue. A phenomenon of solubility appeared as stacks of granules firmly attached to the silver alloy surface. 5. The silver element of the silver alloy powder damaged the gingival tissues slightly, resulting in minor tissue reactions. When the range of copper content was from 0% to 25%, the alloys caused no damage to gingival tissue.

This study was designed to examine the relationship between frequency of silent period and initial occlusal sliding time. The subjects consisted of three volunteers with normal occlusal contacts and three patients with premature contacts. Electromyograms of the bilateral masseter muscles, initial occlusal contacts and jaw movements during the habitual tapping (20-25) were synchronously recorded and replayed using Takamatsu's technique. Results were as follows: 1. The frequency of silent period in the bilateral masseter muscles was 95-100% in subjects with normal occlusal contacts and 34-53% in patients with premature contacts. 2. The silent period latency in three normal subjects was 8.9 +/- 1.3 msec in the left masseter and 13.9 +/- 2.2 msec in the right masseter. The silent period latency in three patients with premature contacts was 12.4 +/- 2.6 msec in the left masseter and 13.9 +/- 8.2 msec in the right masseter. 3. The duration of silent period in three normal subjects was 12.4 +/- 2.6 msec in the left masseter and 11.1 +/- 3.7 msec in the right masseter. The duration of silent period in three patients with premature contacts was 9.1 +/- 1.7 msec in the left masseter and 11.1 +/- 5.6 msec in the right masseter. 4. Initial occlusal sliding time in three subjects with normal occlusal contacts was less than 30 msec, and 98% of all slidings lasted for less than 15 msec. Initial occlusal sliding times in patients with premature contacts were distributed between 6 and 80 msec (40%: 6 to 15 msec, 60%: greater than 15 to 80 msec).(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to investigate the effects of hybrid material compounded with periodontal ligament cells on human teeth and porous hydroxyapatite. As the first step, we tried to produce hybrid materials compounded with periodontal ligament cells and porous hydroxyapatite, and to observe the attachment and invasion of periodontal ligament cells porous hydroxyapatite. Human periodontal ligament cells which had been scraped off the root with a disposable blade were cultured at 37 degrees C in alpha-MEM plus 10% fetal calf serum. The culture cells were attached to the porous hydroxyapatite in vitro. After 3 and 14 days of incubation, the specimens were fixed in gluteraldehyde and examined using SEM. Other specimens were embedded in paraffin and successive specimens were prepared for to remodelling of the attachment and invasion. Many cells attached to the P-HAP granules, and some cells invaded the P-HAP granules. The results suggest that when these hybrid materials are implanted in bone defects, the cells remain in the defect for a certain period, and exhibit the functions and characteristics of itself.

Examination of gingival morphology was conducted using ultrasonic imaging equipment in a 57-year-old female with epulis. The ultrasonogram showed external gingival morphology including epulis and root surface caries which was difficult to detect because of masking by gingival enlargement. It appears that ultrasonograms are useful not only in examining gingival morphology but also in detecting changes in root surfaces hidden by the gingiva.

The purpose of this study was to examine the effect of fibronectin on cell attachment and the growth of cultured cells on the surface of the dentin. In the first experiment, dentin specimens were divided into following three groups: dentin surface polished with carborundum-point, carborundum-point and #150 sandpaper and carborundum-point, #150 sandpaper and #240 sandpaper. The roughness of the surface was measured with a profilometer (Surfcom e-st-sa) for the purpose of comparing differences among the three groups. The foregoing treated samples were added to cultures of periodontal ligament (PDL) cells and following fixation, the number of cells was counted under a light microscope and examination under a scanning electron microscope (SEM) was also performed. 1. Greater numbers of cells attached to the smooth surface (#240) than the rough surface. 2. SEM observations showed increased numbers of attached and proliferated cells on the smooth surface. In the second experiment, the dentin surfaces were polished with carborundum point, #150 and #240 sand paper. The dentin tube side was treated with fibronectin. MEM-treated samples not immersed in fibronectin were employed as controls. The foregoing treated root samples were cultured with PDL cells. Following fixation, the cells attached to the root surface were examined under the light microscope and using a SEM. 1. A significant increase in the number of the attached cells as observed after treatment with fibronectin. 2. SEM observation suggested PDL cells migrated more and proliferated more on the side treated with fibronectin. 3. Fibronectin application increased cell attachment and proliferation more on the smooth surface of dentin.

The purpose of this study was to clinically and microbiologically evaluate the effects of supragingival plaque control, scaling and root planing on periodontal therapy. Six patients affected with moderate or severe periodontitis were selected. The clinical status of each patient was recorded with such clinical parameters as probing pocket depth (PD), probing attachment level (PAL), gingival crevicular fluid flow (GCF), gingival index (GI), gingival bleeding index (GBI), suppurative index (SI), and mobility (Mo). After the patients had learned to perform their own oral prophylaxis, they were treated by scaling and root planing. Microbiological status was assessed by phase contrast microscopy and bacterial forms were classified into following six groups: coccoid cells, rods, filaments, fusiforms, motile rods, spirochetes. The number and the relative proportion of each group were compared statistically. Clinical and microbiological status from baseline to 5 months after scaling and root planing were re-examined. The results obtained were as follows. 1. The most significant change in clinical and microbiological status was observed one month after scaling and root planing. In particular, the total number of the microorganisms and the number and relative proportion of motile organisms were reduced. 2. Thereafter clinical and microbiological status was maintained during experimental period by means of supragingival plaque control.