The ultimate purpose of this study was to find an efficient mode of measuring the depth of a peri-odontal pocket in each phase of periodontal ther-apy, by looking into the number and the location of probing points. In part 1, we measured the prob-ing depth (PD) at six points per tooth in patients with periodontitis (104 persons on their 1 st visit; 84 persons at the time of reassessment of the thera-peutic results), and analyzed the results to compare the diagnostic accuracies of the one-point, four-point and six-point measurement. At the same time, the time required for probing by the three measuring methods was compared in 20 patients. In part 2, we examined postoperative changes in the PD in 33 patients who had undergone regular main-tenance checkups for more than three years. Based on the findings, a thorough search was made for effective measuring points in the maintenance phase of periodontal therapy. The results obtained in part 1 indicated that six-point measurement is the most helpful in making a correct clinical diagnosis. As it turned out, procedure had a drawback in that it takes a long time to complete probing. Four-point measurement was unable to detect 16.9% of affected teeth on the first visit and 47.5% at the time of reassessment, because this method does not cover the mesio-and disto-lingual points, which are the most prone to inflammatory disease. It had been thought that one-point measurement was suit-able for screening because it excels in detecting diseased teeth without taking so much time. In part 2, no significant changes in periodontal pockets were observed throughout the maintenance phase, with the incidence of PD of 4 mm being less than 1%. Therefore, the one-point measurement proved to be useful for screening. However, significant changes were observed in molar teeth and in the points where deep periodontal pockets had been detected at the first examination or at the check up right after active treatment was finished. For the teeth with such points, it was thought that the six-point measurement is needed, while a point-specific method should be developed for such points.

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The objective of this study, was quantitatively examine the effects of Ultrasonic extracts of Prevotella intermedia (P. intermedia). On the phagocytosis by polymorphonuclear leukocytes (PMN) which are major components of the host defense, and the extent of expression of Fcγ and C 3 bi receptors on the cell membrane surface was also studied with a Flow cytometer using PMNs from healthy subjects.
We obtained the follwing results.
1. The ultrasonic extracts of P. intermedia was decreased the phagocytic activity of PMNs in a dose dependent manner.
2. The extent of expression of Fcγ receptors on the cell membrane surface was reduced by stimula-tion of the ultrasonic extract, showing a significant correlation with the phagocytic activity of the cells.
3. The extent of expression of C3 bi receptors on the cell membrane surface was raised by stimula-tion of the ultrasonic extract, indicating a signifi-cant correlation with the phagocytic activity of the cells.
4. Heat treatment at 100°C for 30min or treat-ment with Proteinase K caused the extract to lose its effect on the phagocytic activity and the expres-sion of the receptors.
In conclusion, the ultrasonic extract of P. inter-media was suggested to change the functions of PMN and affect the receptor expression on the cell membrane surface, there by having a close affinity to periodontal disease.

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To develop a new periodontal regeneration tech-nique from the cells of remaining periodontal liga-ment, in teeth involved with advanced periodontitis, this study was designed to examine the possibility of celluler proliferation and migration from remain-ing periodontal ligament of extracted teeth on the root planed and exposed root surface in vitro longi-tudinally.
Thirty teeth specimen were notched at the center along the tooth long axis with root planed coronal half (5.3±1.4mm) and periodontal ligament remaining apical half obtained from extracted canines of seven adult cats. They were cultured for 0, 2, 4 and 6 weeks in vitro. Stereomicroscopic, histological and immunohisto-chemical examinations showed following findings; The distance of cell migaration from the notch at the border of remaining periodontal ligament on the exposed root planed surface was 0.8±0.2mm at 2 weeks. At 4 weeks the distance increased marked-ly (4.6±1.9mm), the cell density was high at the notch and tended to decrease coronally and multiple cell-layers became evident around the notch. At 6 weeks the distance (5.2±1.4mm) and the density further increased and cells covered the whole exposed root planed surface. The number of cells on the surface of the remaining periodontal liga-ment increased and the number of cells inside remaining periodontal ligament decreased longitudi-nally. Alkaline phosphatase (ALP) activity was detected in cells on remaining periodontal ligament and migrated and proliferated cells on the exposed root planed surface 2mm beyond the notch in 6 week specimens. Proliferating cell nuclear antigen (PCNA) was detected in cells on the remaining periodontal ligament and cells on the root planed surface. These results suggested that when the remaining periodontal ligament on extracted tooth was cultured, cells from the ligament could migrate, proliferate, show ALP activity, and cover the root planed surface in vitro.

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We conducted an in vivo study with weekly observations of the relationship between toothbrush bristle wear and brushing force, as well as an in vitro study of the relationship between bristle wear and the removal of experimental plaque. In the in vivo study, we found that the burshing forces em-ployed by the subjects tended to increase as the bristles became worn. The stronger the brushing force, the more the bristles of the outside ranks spread out, while the bristles of the center ranks charged very little regardless of brushing force. Scanning electron microscopic observations of the bristle tips of the center ranks revealed obvious wear of the bristle tips at 2 weeks, and by 4 weeks they had spread considerably. At the tips of the outside ranks, wear of the bristles was slight from the tip. We found that the hardness of the bristles decreased with the use of the toothbrush.
In the in vitro study, we found that the hardness of the bristles decreased with the number of brush-ing strokes and that the actual area cleansed de-creased as the toothbrush became older for all brushing force values. Measurements showed that brushes that had been used for some time removed less gold coating from the experimental apparatus than did newer ones, regardless of brushing force.
These results indicate that toothbrushes should be replaced every 3 or 4 weeks for maximum plaque removal effect.

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This study was designed to clinically investigate the influence of bruxism on molar furcation involve-ment. In the first examination, forty-five patients with furcation involvement were selected and examined for the extent of this involvement, the severity of periodontitis, and the grade of bruxism. In the second examination, 37 patients who had received periodontal maintenance therapy for twenty-two months after the first examination were selected. They were classified into two groups at the time of re-examination : one group wore oc-clusal splints for more than one year; the other wore splints for a limited time period. The obser-vations included the examination of furcation involvement, and ratio of total bacterial number, Porphromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans using an in-direct immunofluorescence technique.
The results showed the furcation involvement to be more severe in strong bruxers. Furcation involvement in the first group improved consider-ably as compared to that of the second group. However, there was no difference in bacterial ratio between the two groups. We speculate that improvement of furcation involvement was due to reduction of occlusal trauma achieved by using occlusal splints and that bacterial flora had little influence on the result.
Therefore, it was suggested that nocturnal brux-ism influences the progression of molar furcation involvement.

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This study was carried out to examine clinical applications of periodontal regeneration therapy using rhBMP-2. Improved fibrous collagen membrane (IFCM 1) and a combination of polylactic acid-polyglycolic acid-copolymer and gelatin sponge (PGS) were used as the rhBMP-2 carrier. The availability of rhBMP-2 and those carriers were evaluated by clinical, radiographic, histopathologic, and histometric observation.
In the 1st experiment, 0.5mg IFCM 1 or 15mm³ PGS were combined with 1, 5 or 10μg rhBMP-2, and implanted on the distobuccal bony plate of canines in cats (N=8). The animals were sacrificed after 3, 5, 7 and 9 weeks and the good combination ratio of rhBMP-2 and each of the carriers were histopathologically examined. The best result were obtained with either 10.0μg rhBMP-2/1.0mg IFCM 1 or 1.0μg rhBMP-2/3.0mm³ PGS.
Following of 1st experiment in the 2nd experiment, materials with the best combination ratio were implanted into artificial classIII furcation bony defect of premolars in cats (N=10). Clinical and standardized radiographic observation were performed at 1, 3, 5, 7, 9 and 12 weeks postsurgically. Healing was generally uneventful without signs of infection. On radiographic observasion increasing radiopacity gradually appeared. The cats sacrificed 6 and 12 weeks postsurgically and then histopathologic and histometric observations were made. Histometric recording included the height of alveolar bone regeneration (NB), the height of cementum regeneration (NC) and the hight of periodontal ligament regeneration (NL). At the rhBMP-2/IFCM 1 site, NB was 2.58mm, NC was 2.50mm, NL was 2.39mm. In rhBMP-2/PGS site, NB was 2.57mm, NC was 2.93mm, NL was 2.62 mm.
These results show that periodontal regeneration with the best combination ratio of rhBMP-2 and each carrier has the potential for clinical application. However, ankylosis was observed in 3 out of 8 teeth in rhBMP-2/IFCM 1 sites and epithelial downgrowth was frequently observed at rhBMP-2/ PGS sites. Further improvements of the carriers are necessary to overcome difficulties encountered in the present experiment.

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Calcified bodies in gingival tissues taken from patients by gingivectomy in the treatment of peri-odontal disease were examined by means of light microscopy, transmission and analytical electron microscopy. The material consisted of 100 gin-gival tissues from patients of both sexes whose age ranged between twelve and seventy-one years. In addition, 23 gingival tissues that had no prominent inflammation were used as control. Specimens for light microscopy were fixed in a mixture of 4% paraformaldehyde and 0.5% glutaraldehyde solu-tion and embedded undecalcified in JB-4. The blocks were cut at 5μm and stained with hematox-ylin and eosin, toluidine blue, PAS, and Von Kossa stains. Samples for electron microscopy were immediately fixed in 2.5% glutaraldehyde, postfix-ed in 1% osmium tetroxide, dehydrated and embed-ded in Epon.
Undecalcified ultrathin sections were stained and examined with a electron microscope. Whereas no calcified bodies could not be found in the control gingiva, calcified bodies of different structures were frequently found in the gingiva biopsies from patients. Among 100 specimens, 64 had some kind of calcified bodies. The calcified bodies were of different character and origin. They were tooth fragments, bone fragments, cementicles, phleboliths, calcified connective tissue, and calcified bacterial aggregations. The results of our study demonstrated that some calcified bodies might develop in the gingiva as a result of chronically inflammation and others might be transplanted into the gingiva following treatments of periodontal disease such as scaling, root planing, and surgical flap procedures. The presence of numerous cal-cified bodies within the gingiva of the previous the treatment of priodontal desease should emphasize the need for careful surgical procedures.

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The purpose of this study was to examine the attachment and growth of cultured cells on the surfaces of titanium plates following polishing by various cleaning methods. The material used in the study was a titanium plate with 99.5% titanium. The titanium plate surfaces was painted with a waterproof felt pen. The paint was removed with various cleaning methods [hand curet scaler (HSc), ultrasonic scaler (USc), Quickjet: powder water spray device (QJ), rubber cup in combination with polishing paste (RC), plastic scaler (PSc) and untreated titanium plate was used as a control (C) ]. The surface roughness was measured using a surface roughness and profile analyzing system. The polished titanium plates were immersed and cultured in a cell suspension of human gingival fibroblasts or osteoblasts. Counts of attached cells were made at 3, 6, 12 and 24 hours. The titanium plates were then observed by scanning electron microscopy (SEM). There were statistically sig-nificant differences between HSc and each value of QJ, RC, PSc or the control (C), and also between USc and each value of RC, PSc or C. SEM observa-tion showed that titanium surfaces polished by HSc or USc had significanly reduced numbers of attached cells as compared to the untreated control surface. The titanium plate polished with QJ showed significantly fewer attached cells than the control surface, but there was no influence on cell form. The cell form and adherence on the titanium cleaned by RC or PSc were well maintained. These results suggest that cultured cells attached to smooth titanium surfaces were in excellent condi-tion as compared with those attached to rough titanium surfaces in vitro. The cleaning methods employing a rubber cup in combination with polish-ing paste or a plastic scaler appeared to be effective for cleaning the titanium surface contaminated with plaque.

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Recently, it has been reported that the guided tissue regeneration (GTR) method produces new attachment and alveolar bone, and that bone mor-phogenetic protein (BMP) induces new bone in artificial bone defects or ectopic sites. However, it is still unclear if new attachment can be gained with BMP. As the first step in obtaining bone regenera-tion with new attachment, we have investigated the heterotopic bone formation of hybrid materials combined with osteogenetic cells and porous hydroxyapatite (HAP) in vivo.
We used rat bone marrow cells and first sub-cultured cells of bone marrow as osteogenetic cells which have the possiblility of differentiating into osteoblasts. These cells were cultured with porous HAP granules for 1 week using a-MEM sup-plemented with dexamethazone, β-glycerophos-phate and ascorbic acid.
Hybrid materials combined with osteogenetic cells and HAP granules were cultured with PBS for 3 hours before implantation, and then implanted into ectopic (subcutaneous) sites in rats. At 5 weeks after implantation, these specimens were examined histologically. New bone formation was observed on the surface of HAP and the inside of HAP. However, HAP implantation without osteogenetic cells produced no bone formation.
Our results demonstrate that the hybrid materials (containing both bone marrow cells and first sub-cultured cells of bone marrow) can form new bone at ectopic (subcutaneous) sites.

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The purpose of this study was to evaluate the efficacy of the 3-dimensional computed tomogra-phy image (3D-CT) for diagnosis of the morphol-ogy of intrabony defects in periodontal patients.
Thirty-eight tooth surfaces of 5 periodontal patients, (2 female and 3 male) were selected. The intrabony defects were confirmed by oral photogra-phy during a flap operation. Ten periodontists excluding the flap operator diagnosed them by the 3 D-CT, (CT method), radiography only, (R method), and radiography plus pocket probing (R+P method). The items of diagnosis were presence or absence of intrabony defects on the buccal and lingual aspect, interproximal aspect, and buccal and lingual bony wall in interproximal intrabony defects. Diagnostic accuracy was evaluated by receiver operating characteristic (ROC) analysis. The results were as follows: 1) The diagnosis of the intrabony defects on the buccal and lingual surface by the CT method was signifficantly more accurate than by the R method, but equal to the R+ P method. 2) The accuracy of diagnosis of the interproximal intrabony defects was almost equal among the three methods. 3) The buccal and lin-gual bony wall in interproximal intrabony defects was diagnosed more accurately by the CT method than the other two methods. From the above points of view, it is considered that 3D-CT is effi-cient in diagnosing the intrabony defects of alveolar bone.
Thus, 3D-CT may have great ability to diagnose the intrabony defects of alveolar bone.

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The present study was undertaken to assess the cleansing effects of a new type of electric tooth-brush (a counter-rotating, compact type).
Three toothbrushes were tested: (1) Interplak, a conventional counter-rotating, 2-row, 10-line elec-tric toothbrush, (2) new Interplak, counter-rotating, 2-row, 6-line electric toothbrush, and (3) GUM # 211, a manual toothbrush. Two models of gingival recession were used: (1) the 1.5mm recession model, and (2) the 3.0mm recession model. A normal gingival margin model was also used. When the electric toothbrush was used, each tooth surface was brushed for 15 seconds, with the brush maintained at a right angle to the tooth surface. When the manual toothbrush was used, each surface was brushed for 15 strokes using the scrubbing method. Brushing pressures were measured using a pressure measuring device. This measurement was repeated 5 times for each model using a con-stant 250g pressure. To calculate the artificial plaque removal rate, a standard photographic appa-ratus, taken from the buccal, lingual, mesial and distal sides, were fed into a computer via a scanner, and the area occupied by residual plaque was measured on NIH images.
The data were analyzed statistically using two-way ANOVA. The plaque removal rate for the normal gingival margin model and the 1.5mm recession model was high, in the order of conventional electric tooth-brush>new electric toothbrush>manual tooth-brush. The plaque removal rate for the 3.0mm recession model was high, in the order of conven-tional electric toothbrush>manual toothbrush> new electric toothbrush. The plaque removal rate for the proximal surfaces of molars in the recession models was higher with the new electric toothbrush than with either of the other two toothbrush.

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This study was carried out to assertain the con-ditiors of cases who had undergone periodontal surgery from January, 1995 to December, 1995 in our clinic and to compare these results with those of 10 years previously.
The following results were obtained.
1. The operative cases were 121 (68 males and 53 females) and the average patient age was 51.0 years old.
2. The progressive stages of periodontitis at the time of surgery were as follows. mild: 3.6%, mod-erate: 44.6%, severe: 51.8%.
3. The main purpose of surgery was elimination of periodontal pockets (59.7% of cases), followed by improvement of furcation involvements.
4. As regards the classification of these opera-tions, there were 98 flap operation cases, 54 perio-dontal osseous surgery cases and 33 furcation-involved surgery cases.
5. According to the results of the preoperative evaluation, the plaque control record was under 20% in 67.6% of all cases and the bleeding index was under 20% in 69.5% of all cases.
6. The flap operation had been done mainly for the 5mm pocket depth cases. The furcation-involved surgery had been done mainly for the degree 3 involvement cases.

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The purpose of this study was to compare the clinical effects of surgical therapy in smokers and non-smokers.
Fifty-Seven patients (age range 27-66 years, average 49.9 years), 32 men and 25 women, were investigated.
Twenty five of the patients were smokers and 32 were non-smokers. The patients had moderate to severe periodontitis with persistent diseased sites (probing depth 4mm or more) after non-surgical therapy. The surgical modalities used were the modified Widman flap operation or the apically repositioned flap operation.
Re-examination was done 2 months or more after surgery.
The oral hygiene status and gingival bleeding index were similar in the two groups. No differ-ences were observed regarding probing depths except for palatal pockets of the maxilla where a significantly greater probing depth was observed in smokers (P<0.05).
The results suggest that smoking may impair the outcome of surgical therapy.

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The purpose of this study was to clinically evalu-ate the coverage of facial gingival recessions by Semilunar Coronally Repositioned Flap at the 18 months. The subjects were 12 patients and 18 exposed roots of Miller Class I recessions (verti-cal ression depth of 4.0mm or less) on the maxil-lary anterior teeth. Clinical assessments included vertical recession depth (VRD), probing pocket depth (PPD), probing attachment level (PAL), and keratinized tissue width (KTW). These mea-surements were taken with a pressure sensitive prove (TPS probe) in 20 g of probing pressure at the before surgery and every 6 months after sur-gery. The results showed that the mean of the root coverage was 1.8mm (92.1% of vertical root cover-age ratio), and the mean of the probing attachment gain was 1.9 mm at the 18 months after the surgery. Statistically significant differences were found between the result of the 18 months after the sur-gery and at the before surgery (p<0.0001). The mean of increase keratinized tissue width was 0.4 mm, and the mean of probing pocket reduction was 0.2mm, but there were no statistically significant differences were observed. Furthermore, the clini-cal evaluation of these periodontal parameters that compared with natural teeth group and prosthetic teeth group in the subjects, in natural teeth group may obtained a slightly satisfactory results, but there were no statistically significant differences.

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