Stages of the development of the junctional epithelium (JE) during molar tooth eruption in Wistar rats were studied at the ultrastructural level and following results were obtained.
1) At the time of first emergence of the cusp tip into the oral cavity, prominent bud-like proliferation of the external cells occurs throughout the lateral side of the reduced enamel epithelium (REE). With progress of tooth eruption, these newly formed epithelial cells provided with well-developed Golgi complex and lysosome-like bodies successively replace the preexisting REE cells and are transformed into flattened cells arranged parallel to the enamel surface presumably by means of the cytoplasmic reorganization with autophagosomes. It is evident that the JE immediately after completion of the eruption totally consists of the odontogenic epithelial cells derived from the REE.
2) With exposure of the cusp tip into the oral cavity, intracytoplasmic vacuoles begin to appear within the external cells already transformed into squamous cells. Leukocytic emigration into the epithelium also starts with tooth exposure. These vacuoles rapidly increase their number and extent as the tooth eruption proceeds and finally exhibit the similar morphology and distribution pattern to those characteristic of the mature JE. These findings strongly suggest that they are phagocytic vacuoles and play an important role for defense mechanism in highly permeable JE.
3) Separation between the tooth crown and the gingiva during eruption does not occur at the dento-e pithelial junction but is constantly observed as a tear within the REE or JE. A layer of non-vacuolated epithelial cells always persist adhered to the tooth surface facing the crevicular space. It seems, therefore, that the gingival sulcus in rat molar gingiva develops by degeneration and shedding of the cells constituting a superficial (coronal) portion of the JE.

抄録全体を表示

In the present study the effects of sonicate preparation of oral microorganisms on the humoral immune responses were investigated in mouse spleen cell culture by the direct antibody plaque technique.
Actinomyces viscosus, Veillonella alcalescens, Fusobacterium nucleatum and Bacteroides melaninogenicus were cultured anaerobically in liquid growth media. Microbial cells were collected and lyophilized. After the bacterial suspension was sonicated and centrifuged, the supernatant was filtered sterilely and then heated for 30 minutes at 56°C. The protein content of the sonicates was determined according to the method of Lowry. Unsensitized and in vivo sensitized AKR mice spleen cells by the sonicates were suspended in RPMI 1640 medium containing 10% heat-inactivated fetus calf serum. Sheep red blood cells and three concentrations (10^-3, 10^-2, 10^-1) of the sonicates were added to the spleen cell suspensions. The resulting preparations were incubated for 4 days at 37°C in an atmosphere of 5% CO₂-95% air. The results were estimated by counting the numbers of direct plaque forming cell (PFC) in the spleen cell culture.
The following findings were obtained:
1. Non-heated sonicates with 10^-3 and 10^-2 concentrations from four oral microorganisms did show the enhancement of antibody formation.
2. The number of PFC increased after stimulation with 10^-2 and 10^-1 concentrations of the heated sonicates as compared with the control. The adjuvant indices with 10^-1 concentration of the sonicates were as follows; A. viscosus: 6.6, V. alcalescens: 3.8, F. nucleatum: 2.4, B. melaninogenicus: 2.8.
3. The kinetic response of PEC to 10^-2 concentration of four heated sonicates was characterized by an increase in the number of PFC on 3, 4, 5th day of cultivation and the number on 5th day was more six fold than the control.
4. It was suggested that four heated sonicates with 10^-1 concentration were capable of inducing the polyclonal B cell.
5. In vivo sensitized mice spleen cells by the sonicates from A. viscosus, F. nucleatum, B. melaninogenicus increased in the number of PFC, while the number decreased after stimulation with V. alcalescens, when compared to unsensitized mice spleen cells.

抄録全体を表示

The present study was performed to elucidate the variation of kinin contents and kininase activities in the saliva, plaque and gingival fluid of the healthy people without oral hygiene.
Nine male dental students, aged 20-24, were the experimental subjects. All of the participants had a tooth scaling and polishing, and then they were instructed not to brush their teeth for the following 10 days. At the 11th day, they were allowed to have a tooth brushing (Rolling method) 3 times a days for 5 days. The collection of samples (saliva, plaque and gingival fluid) and clinical examinations were performed daily for the entire experimental period (16 days). Kinin contents and bradykininase activities in the samples were assayed by a biological method of Takeya et al. The bradykininase activity was determined by measuring the percent of inactivation of added bradykinin (1μg/ml).
The following results were obtained;
1. The plaque index, gingival index and amount of gingival fluid were increased throughtout the period without oral hygiene (10 days). These clinical scores showed a rapid decline when the oral hygiene procedure was resumed.
2. Kinin contents in the samples were almost zero for 5 or 6 days after stopping of the oral hygiene, and then it increased gradually for the following 4 or 5 days. The oral hygiene procedure was resumed at 10 days, and after that kinin contents decreased rapidly until these were not measured in the samples.
3. Bradykininase activities in the samples decreased gradually after the oral hygiene was stopped, and these enzyme activities disappeared at 4-5 days after stopping of the oral hygiene. But, after the resume of oral hygiene, the enzyme activities rapidly increased to the level of the first days of the experiment.

抄録全体を表示

Measurements of total hydroxyproline levels in human sera were carried out on 11 clinical healthy subjects ranging from 23 to 27 years of age, and in 57 patients with periodontal disease ranging from 16 to 64 years of age.
The correlations between hydroxyproline levels and a few indicies of periodontal disease were discussed in order to estimate hydroxyproline levels as an index of periodontal tissue destruction.
The following results were obtained.
1. Hydroxyproline levels in sera were constant regardless of age group.
2. Hydroxyproline levels in sera of patients were higher than the levels of clinical healthy subjects. But there was no significant difference in them.
3. No significant correlations were found out between indices of periodontal disease, i. e. Gingival Bone counts, Gingival scores, Bone scores and Salivary leucocyte counts, and total hydroxyproline levels in sera. But there was seen a significant correlation only between Bone scores and hydroxyproline levels in sera of clinical healthy subjects.
Some factors concerning hydroxyproline levels in sera are to be studied.

抄録全体を表示

The irritation property of dextranase which was derived from Chaetomium gracile was determined to the rabbit skin and eye, and to the hamster cheek pouch membrane.
1) Rabbit skin; Cotton cloths containing 300000 units/0.5ml of dextranase were patched on intact or abraded skin of the rabbit. After 24 and 72 hours, the irritancy of dextranase to intact or abraded skin were almost the same. After 24 hours only one out of three animals indicated slight erythema, and the irritation index was 0.2.
2) Rabbit eye; On the rabbit eye 60000 units/0.1ml of dextranase was dropped once. After 1, 24, 48, 72 hours and 7 days, the irritancy of dextranase was observed according to the Draize's method. After 1 hour only one out of three animals indicated slight hyperemia of conjunctivae, and the mean total irritation score was 0.3.
3) Hamster cheek pouch membrane; During 7 days, 1200000 units of dextranase was administered once a day in hamster cheek pouch by means of liquid or powder. However, any significant change could not be observed by the naked eyes or microscopic observations.
These results suggested that the irritation property of dextranase to skin, eye and oral mucosa may be very slight or none. In particular, 20000 units/g of dextranase in the tooth paste may be out of question in its regular use.

抄録全体を表示

Kinins are generally considered as important chemical mediators in inflammatory process. However, the role of these mediators in periodontal disease still remains unknown. Recently, Omori and Mizuno measured bradykininase activity in gingival fluid of the patients with periodontal disease and compared it with various clinical findings. They showed that this enzyme had a marked correlation with PMA-Index score (P<0.01), plaque score (P<0.001), calculus score (P<0.01) and pocket, depth (P<0.001).
The present study was performed to know the effect of scaling and brushing on both the variation of bradykininase activity in pocket exudate of the patients with periodontal disease and their clinical findings.
Twenty seven patients with periodontal disease (10 males and 17 females, aged 16 to 46) were examined in this study. The subjects were separated in two groups, the first group having only a scaling and the second group receiving a scaling and a brushing. The pocket exudate was collected from periodontal pocket by filter paper strips just before and a week, two weeks and three weeks after the treatment. After the strips were weighted, they were dipped in the inhibitor (Trasylol) and then homogenized by Polytron homogenizer. The mixture was centrifuged at 2, 500g for 20min. at O°C and the supernate was used as assay. The bradykininase activity was determined by measuring the amount of pocket exudate (mg) which inactivated 50% of added 1μg/ml bradykinin (biological method using guinea pig ileum)
The results of study showed that PMA index, plaque index, pocket depth and exudate quantity decreased more significantly in scaling and brushing group than in only scaling group.
In both groups, the bradykininase activity in pocket exudate had a tendency to increase with improvement of periodontal condition, paticularly in scaling and brushing group.

抄録全体を表示

Extract solution from commercially available periodontal dressing materials (Septo-pack———Septodont Co, LTD., France, COE-pak [Hard & Fast set]———Coe Laboratories, U. S. A.) were injected in subcutaneous of rabbit's back, and were examined on capillary permeability.
The results obtained were as follows:
1. Extract solution from Septo-pack was accelerated capillary permeability of every experimental period (1-day, 3-day, 5-day, 7-day, 10-day and 14-day).
2. Extract solution from COE-pak [Hard & Fast set] and control (physiological saline solution) have not showed capillary permeability.

抄録全体を表示

The important role of plaque control has been recognized recently. The goal of plaque control is based on a continuous activity by patient himself. It is a main point that dentist gives them propelling power to lead them to the activity; that is “Motivation”. And how to motivate the patient is a great subject.
There are many clinical reports of motivation, however it was very hard to find corroborative studies concerning estimation of the effect of motivation for plaque control. H. M. Goldman emphasized the importance of motivation in 1940, and stated that initial preparation combined with tooth brushing is essential to the all patients with periodontal disease. We believe that motivation to all dental patients is indispensable to control plaque thoroughly.
The purpose of this experiment is to make clear the effect of motivation in tooth brushing instruction. The patirnts were separated to three groups as follows; 1) Brushing instruction without motivation 2) Motivation with brushing instruction 3) Control. The amount of plaque accumulation was measured before and after the experimental period. To standardize the contents of motivation and tooth brushing instruction for individual patients, a home made cassette tape was prepared and presented on closed circuit TV. Any personal chair side instruction was not given during experimental period. Plaque was stained using liquid of Plak-Lite and was evaluated by U. S. Navy Plaque Index (Modified).

抄録全体を表示

This study was carried out to know the plaque accumulation relative to the contour of artificial crowns. A total of 32 molar teeth from 17 patients being set artificial crown on one side of a jaw and the teeth of opposite side having no treatment were selected. The surface of the teeth and artificial crowns were polished. Then the patients were indicated not to use the tooth cleaning devices for 48 hours and the accumulation of plaque was measured. The length from gingival margin to the most convex point of the natural teeth and artificial crowns were measured facially and lingually.
The following results were obtained:
1) On the artificial crown, plaque was less accumulated.
2) It was seemed that the accumulation of plaque was observed more on the overcontoured crown than undercontoured crown.

抄録全体を表示