Shiro Kinoshita

A New Method for Measurement of Both Tooth Contact Area in Occlusion and the Occlusal Force

In spite of the well-known facts that trauma from occlusion is one of the most important factor to destroy periodontal tissue, only a few studies regarding the force itself which was added to the tooth surface of individual tooth have been carried out. It seems very important to know the occlusal tooth contact area and the degree of occlusal force.A new method was designed to measure the occlusal contact area on each tooth and the degree of pressure which was added to each contact area on one tooth. Both occlusal areas and the pressure on any one of occlusal contact areas were measured by using occlusal paper, 200μthickness, called “Prescale” by Fuji Photo Film Corporation.Prescale consists of two paper-seats and numerous microcapsules containing a red dye between the paper-seats. When the teeth are brought into occlusion, these microcapsules rapture and discharge the dye staining one of the papers red. The density of the color is in proportion to the degree of pressure added.Tooth contact areas in occlusion recorded on “Prescale” were enlarged by a projector and measured by dental area analyzer.The density of the color was measured with a densitometer after enlarging the colored area under a microscope. This densitometer was improved to measure the density of color limited to an area of diameter less than 1mm. As a sensor of this densitometer, CdS photo cell was used.To study the reproducibility of this method, a study model which teeth are made of metal was used. This study model was fixed on a articulator. Standarized force was added to the articulator ten times.Both occlusal contact area and the pressure added to the same contact area showed almost the same value. From the results obtained, this method basically seems to be a simple and feasible technique for measuring occlusal contact area and the pressure of small contact areas in occlusal surface. Then clinical appliance using few patients was performed. But the reproducibility could not be obtained. It is thought that this result was caused by the thickness of Prescale and that the paper must be improved.

High proteolytic activity in the periodontal pocket.

Neutral proteolytic enzymes have been demonstrated in saliva (MAKINEN, Acta Odontol Scand 24: 709-721, 1966), dental plaque (FROSTELL and SODER, Int Dent J 20: 436-450, 1970), and gingival fluid (KORBER and SCHAUER, Dtsch Zahnaerzt 22: 332-337, 1967). High levels of the acid proteolytic enzyme, cathepsin D, have been found recently in the gingival fluid in instances of advanced periodontitis (ISHIKAWA; CIMASONI; and AHMAD-ZADEH, Arch Oral Biol 17: 111-117, 1972). Gelatin such as that making up photographic emulsions can be used as a substrate for demonstrating proteolytic activity. The photographic emulsions are processed through developer solution and a fixing bath; they are insoluble in water and are known to be hydrolyzed by proteolytic enzymes (DAOUST, Int Rev Cytol 18: 191221, 1965). The use of gelatin-silver films as a substrate reveals the activity of a group of enzymes rather than that of a particular enzyme because many proteases are able to act on gelatin. Adams and Tuqan (I Histochem Cytochem 9: 469-472, 1961) use the term proteolytic activity in referring to the activity demonstrated by this method. The purpose of this study was to compare the proteolytic activity in saliva, dental plaque, and gingival fluid by the use of gelatin-silver films in vitro and to study the distribution of this activity within the pocket in situ by using the same roll of film. Each drop (about 0.05 ml) of mixed saliva (untreated and heated at 100 C for five minutes), fresh dental plaque (50 mg wet weight/ml in phosphate buffer at a pH of 7.1), distilled water, and 5 ,1l of gingival fluid, collected by the method of Sueda, Bang, and Cimasoni (I Dent Res 48: 159, 1969) were placed on small sheets of filma blackened after exposure to daylight, development, and fixation. The films then were transferred to a covered Petri dish containing a

Prevalence of Periodontal Disease in 15-year-old Schoolchildren in Japan

The purpose of this study was to determine the prevalence of periodontal disease in 690 15-year-old school children, living in Tokyo, Japan. This clinical survey was performed prior to the roentogenografic examination which was intended to study the prevalence of marginal bone loss.Plaque Index (by Silness and Loe) and Gingival Index (by Loe and Silness) were recorded on maxillary right first molar, left incisor, first premolar, mandibular left first molar, right premolar and right incisor. Pocket depth was measured in mm at the six teeth, maxillary and mandibular first molars, and incisors on the mesial sides. Bleeding Index during probing (by Ainamo) was also recorded.The means of the Plaque Index were 1.00 and 1.30 in girl and boy students respectively. The girl students were statistically superior (p<0.05) than the boys in oral prophylaxis. About 60 per cent of the children exhibited gingival inflammation as indicated more than 1.00 of Gingival Index. Very severe inflammation more than 2.00 of Gingival Index was observed about 1 per cent among the school children. About 30 per cent of the examined teeth showed pockets deeper than 2mm. About 10 per cent of the examined teeth were bleeded on probing.These results suggest that periodontal breakdown was occured on more than 10 per cent the 15-year-old school children. Periodontal care and education are necessary to early teen aged children.

A Simple Device for Taking Standardized Intra-Oral Photographs

Standardized intra-oral photographic device is very useful for longitudinally evaluating plaque accumulation or degree of inflammation. Many devices are developed for this purpose, but most of them seem to have some short-comings for simple clinical use. A simple device for taking intra-oral standardized photographs with high reproducibility was developed. The device is composed of a camera (Medical Nikkor, Auto 1: 5.6, f=200mm), a circular attachment to the lens of the camera made of acrylic resin, and a distance-adjustable tripod connected to the attachment. Using this device, intra-oral photographs of labial aspects of upper central incisors were taken. The subjects were ten dental students and two faculties. Two examiners (K. I., M. F.) took photographs once a day for one subject. Reproducibility of this device was studied calculating repeatedly the area of the same tooth surface on slides which were projected on a section paper (5mm square). The distance between two special points on a tooth was also calculated for studying the reproducibilty of the device. The average coefficient of variation for the area of a tooth was 3.2%, and 1.6% in the case of the distance between two special points of a tooth. From these results, this device seemed to be a very simple method for taking standardized intra-oral photographs with high reproducibility.

A Clinical Assessment of Creeping Attachment After Free Gingival Graft.

Free gingival grafts have been used to repair periodontal deformities resulting from gingival recession. The review of the literature has, however, revealed only a few report of successful root coverage by this technique. The cases of successful root coverage by free gingival grafts technique were presented. In this study, 6 areas of localized gingival recession with root exposure were treated. Following surgical treatment (free gingival grafts) the patients mere examined at intervals of 3, 5 and 8 years and creeping attachment was found in all cases. The creeping attachment ranged from 1 to 3.1mm, an average of 2mm. It is concluded that creeping attachment dose occure following free gingival grafts and the root coverage has been observed during 8 years.

A Clinical Study of Periodontal Status Following Surgical Procedures

Changes in alveolar bone following various periodontal surgeries were studied. The 55 surgical treatments were performed on 16 patients with periodontal disease. Radiographs were taken at the surgical regions by using the standardized X-ray technique. The interdental bone areas were measured on the X-ray films. The measurements were followed up to a period of three to four years. At the same time, various periodontal indices were also recorded. In addition, when a flap operation was performed, the type of bone defect was evaluated and recorded.The results were as follows:(1) Loss of alveolar bone was observed until 2 months after surgery and then new bone formation was observed, (2) Among various periodontal surgeries, flap procedure demonstrated most bone loss post-operatively, gingivectomy showed moderate bone loss but following gingival curettage, apposition of new bone was observed 1 month after operation.(3) Among various pattern of bone defects, the areas with horizontal bone loss showed an increase in bone apposition after 3 months post-operatively but in contrast the defect with one wall showed resorption of alveolar bone.(4) The changes in alveolar bone were not correlated to the plaque index 10 months after operation, however 3 or 4 years postoperatively, the correlation between these two factors was significant statistically.(5) The changes in the alveolar bone observed at an interval of 6 months and 3-4 years were found to be independent of the changes in the depth of periodontal pockets.(6) The lamina dura re-appeared rapidly between 3-6 months post-operatively and then the rate of appearance levelled off at about 50%.

The Plaque-Removing Effect of Natural and Synthetic Bristle Toothbrushes

Purpose of this study was to know the effect of natural and synthetic bristle toothbrushes on plaque removal.Two kinds of natural toothbrushes (animal bristle and pig bristle) and two kinds of synthetic toothbrushes (nylon bristle and rubber) were evaluated using Scrub brushing method. Twelve adults, 6 patients and 6 dentists, 6 males and 6 females, aged 19 to 42, volunteered for this study.Plaque score was calculated with the modified Volpes method which Suzuki et al. reported before. Facial and lingual tooth surfaces of the six representative teeth (6/41|14/6) were scored, after disclosing the plaque with a 0.5% basic fuchsin.The average percentage of plaque removal on facial and lingual tooth surfaces were as follows.(1) 59.6±16.1% (nylon bristle) (2) 42.3±13.2% (pig bristle)(3) 39.8±14.7% (rubber) (4) 39.5±13.3% (animal bristle)There was a statistically significance at the 5 percent level of confidence between nylon bristle brush and the other three brushes.A similar trend was recognized on labial, lingual, medial and papillary tooth surfaces independently.The scores after brushing were evaluated, also.(The materials of animal bristles are of horse and badger hair.)

The Abrasiveness by Modern Dentifrices

This study was performed to examine the effect of modern dentifrices on the abrasion of acrylic resin and human teeth.Those specimens were brushed with a tooth brushing machine for two hours, corresponding to 3000 back and forth strokes. The surface irregularities of the specimen were analyzed by a surface analyzer, and observed by scanning electron microscopy before and after the brushing procedure. The weight loss of the test specimens of acrylic resin materials was determinded, weighing them before and after brushing by a microbalance.The effect of hardness of toothbrush on the abrasion was tested, using three different toothbrushes.The abrasiveness by the dentifrices showed a wide range.All dentifrices except one dentifrice which did not contained abrasive materials had considerable abrasive effects on both acrylic resin and human teeth. There was a high correlation (r=0.96) between the weight loss and the surface irregularities in the case of acrylic resin.Without using dentifrices, abrasion was not observed on both acrylic resin and human teeth.

The Double Blind Test on Plaque Control Effect of Mutanolysin and Chlorhexidine Gluconate Using a Water Pressure Irrigating Device

This investigation was designed to study whether mutanolysin and chlorhexidine gluconate using a water pressure irrigating device was effective in removing or preventing formation of dental plaque. The nine subjects were devided into three groups of three subjects each according to a Latin Square design. Each subject took part in three cycles of oral prophylaxis, mouthwash assignments and accumulated plaque evaluation for a three week period.The results of an analysis of variance showed statistically significant difference at 1 percent level between the chlorhexidine gluconate group and placebo group and at 5 percent level between the mutanolysin group and placebo group. The difference between chlorhexidine gluconate group and mutanolysin group was also significant (p<0.05). Chlorhexidine gluconate was more effective on dental plaque than mutanolysin. The plaque control effect of chlorhexidine and mutanolysin was more striking in labial surface than in any other surfaces of the teeth.

Case Report of Acute Necrotizing Ulcerative Gingivitis

Four cases of Acute Necrotizing Ulcerative Gingivitis (ANUG) were reported in this paper. These cases were diagnosed as ANUG clinically, histopathologically and bacteriologically. The patients with ANUG were treated systemically and locally. Local treatments were very effective. From these findings, it was suggested that the local factors were responsible for ANUG rather than systemic factors, and that the clinical features were modified and accelerated by systemic backgrounds.