Obligate anaerobic gram-positive cocci inhabiting the clinically healthy gingival sulcus area of the lower premolar and first molar were examined quantitatively and qualitatively. Four subjects aged 25 to 35 years were included in the study. Out of a total of 387 isolates, 155 (40.10) were obligate anaerobes, of which 23 (5.9%) were categorized as gram-positive cocci. These 23 isolates were investigated with regard to morphology, biochemical reactions and fermentation products. Nine of these isolates forming chains in the broth media could be considered as belonging to GenusPeptostreptococcusand were divided into 4 groups. Two strains (Group 1) resembledPeptostreptococcus intermediusand 3 strains (Group 2) werePeptostreptococcus evolutusbut in Bergey's Manual (8th ed.) these are classified as GenusStreptococcusdue to lactic fermentation. Three (Group 4) were similar toPeptostreptococcus micros. But the remaining one strain could not be identified. Fourteen strains of anaerobic gram-positive cocci forming irregular masses but no chains in the broth media were considered to belong to GenusPeptococcusand were divided into 4 groups. One strain (Group 2) of these organisms resembledPeptococcus aneerobius, 11 strains (Group 3, 4) were probablyPeptococcus constellatusbut 2 strains (Group 1) remained unidentified. As revealed in the present study, the anaerobic gram-positive cocci in the dental plaque were comprised of many types of bacteria, and in most of them it was difficult to identify the species because of the variability in the biochemical characteristics. On the other hand, peptostreptococci isolated from the dental plaque in this experiment did not contain the species which were frequently found in the pathological specimens of the anaerobic bacterial infections.
Dental plaque materials were collected from the buccal surface of the upper incisor of adult subjects, who had clinically healthy tooth and gingiva, at 0, 1, 4 and 12 hours after tooth brushing by abrasing with sterilized cotton wool. The samples were suspended in sterilized saline and diluted. An appropriate dilution was inoculated onto the BHI-blood agar plates and incubated aerobically and anaerobically for 48 hours at 37°C. The colonies were collected randomly from the cultured plates, purified through 2 to 3 subcultures and classified into bacteria types. Streptococci were the most predominant in both cases of aerobic and anaerobic cultures, being more abundant in the former. This was followed by the catalase-producing, gram-positive filamentous organisms, including theRothia. Neisseriawere less predominant but were detected in all of the samples. In the 1-hour sample, bacteria other than streptococci, filamentous andNeisseriaaccounted for 40 to 600 of the total microorganisms but were variable in types. Strict aerobic organisms were decreased from 39% to 18% with the passage of time after brushing. Strict anaerobes also decreased from 24% to 5%. The results indicated that the natural formation of plaque on the tooth surface is established in about 4 hours after tooth cleaning. The types of bacteria were, however, different from those found in the saliva, epithelia or in the gingival crevice area, and, therefore, obviously the source of the bacteria in the early stages of dental plaque could not be determined.
The effect of the newly developed vibration etching technique using a fissure needle for fissure sealing was investigated by clinical trial in comparison with the conventional simple etching technique. The findings were as follows: 1. With the simple etching technique, about 300 of the cases showed complete retention with no marginal fracture after one year. Marginal fractuer at the ends of the fissures spread with time in many cases, resulting in a loss in about 10% of the sealed pits. 2. With the vibration etching technique, more than 70% of the cases showed complete retention after one year. Marginal fracture at the ends of the fissures rarely spread with time and the loss in the pits was less than 2%. 3. The sealant in the pits having incipient caries was lost in none of the cases.
The extracted human teeth with a broken reamer in the root canal were embedded in agar and treated by iontophoresis with 3% ammoniacal silver nitrate. By means of transparent specimens, the distribution of the metal ion in the teeth was observed with a stereoscopic microscope. The results obtained were as follows: 1) In the case with a black stain in the agar, the silver ion was reached the root apex. The canal wall from the area with a broken reamer was stained black on the apical side and the electric resistance of the teeth was increased. 2) In the case with a brown stain in the agar, the ferric ion of the reamer which broke in the root canal was eluted. The canal wall from the area with a broken reamer was stained brown on the apical side and the electric resistance of the teeth was decreased. 3) In the case with a black and brown stain in the agar, both the silver ion and the ferric ion of the reamer which broke in the root canal reached beyond the root apex. The canal wall from the area with a broken reamer was stained black as well as brown on the apical side and the electric resistance of the teeth was increased. 4) In the case without any stain in the agar, nothing reached the apical region. However, a black stain was observed in the dentin in the cervical region of the teeth and the electric resistance of the teeth was increased.
A number of studies have been reported on the evoked responses recorded from the peripheral nervae or central nervous system, which were elicited by the stimulation to the tooth pulp. There are, however, few studies on the interaction between the impulses from the tooth pulp and those from the various areas of the body. In this report, the influence of the conditioning stimulus delivered to several areas of the body (nose, cheek, earlobe, hand, shoulder, foot and back) on the cortical evoked potential (C.E.P.) produced by the tooth pulp stimulation was physiologically evaluated in the cats. The results were as follows: (1) The amplitude of the C.E.P. was increased by the increase of the stimulating strength of the test stimulus to the tooth pulp, with the stimulus to the gingiva being constant. (2) The amplitude of the C.E.P. elicited by the test stimulus was remarkably decreased by the application of the conditioning stimulus to the intra-segmental area and moderately decreased by that to the extra-segmental area. (3) The change in the amplitude of the C.E.P. elicited by the stimulation to the skin of the cheek was scarcely observed, when the test stimulus was preceded by the conditioning stimulus to the tooth pulp.
This study was attempted to evaluate the efficacy of the removal of the demineralized dentin layers by staining with 1.0% acid-red propylene glycol solution and to investigate the toothadhesive resin penetration into the etched dentin after the removal of carious lesion. Using vital or extracted teeth decayed to a medium degree, the prepared specimens were examined by microscopic observation, microradiography, bacterioscopy and SEM. 1) By repeated staining and excavating of the decay, the dentin layers beneath the lesions gradually varied in color of red, pink and light pink. Finally, the deeper layer was not stained and coincided with the transparent zone. 2) The bacteria remained in the red-stained dentin and partially in the pink-stained dentin. 3) When the natural discolored dentin was thoroughly removed, the superficial layer of the transparent zone without the bacteria became exposed. 4) The resin penetrated into the stained dentin or the natural discolored dentin to a length of several hundred micrometers but penetrated little into the unstained dentin or the exposed dentin after the removal of the discolored dentin. 5) The resin tags produced in the stained dentin or the discolored dentin showed a smooth surface with lateral extentions and a rough surface of 1 to 1.5μm in thickness. 6) The resin tags produced in the unstained dentin or the layer after the removal of the discolored dentin characteristically were of tube shape of about 10μm in length or tube containing thin projections.
The purpose of this study was to examine the numerical expression of the mandibular symphysis by using the Fourier analysis. The sample consisted of 64 cephalometric tracings on the mandibular symphysis obtained from 32 Caucasian children with Bjork's metallic implants. Serial cephalograms were taken at 3 years before and after the maximum pubertal growth. The from of the mandibular symphysis was reprsented by the angle and the length from the centroid point which was located within the symphysis. The raw data series were transformed to the propotional data series against the summation of each data series in order to eliminate the size factor. The conclusions were as follows; 1) Eigthy percent of the proportional data series could be expressed by using the first 2 power spectrum values based on a set of independent parameters. 2) By using the first 2 power spectrum values, it was recognized that the pattern classification and the morphological analysis were effective. 3) Sufficient durability of the pattern similarity with growth between the individuals was not recognized in all of the cases.
The experiments were carried out in order to investigate the tissue distribution of Lipiodol Bleomycin (L-BLM; 15 mg/ml) among the various organs by the bioassay method using Bacillus subtilis and the histologic changes of the regional lymph nodes and other organs after intralymphatic injection of L-BLM (3mg/kg) in rabbits with VX2 carcinoma and their controls. The summary of the results is shown below: 1) A high concentration of BLM in the control rabbits immediately after the injection was found in the blood, primary and secondary lymph nodes, skin, spleen, stomach and colon. All of the organs examined in the rabbits with VX2 carcinoma showed a remarkable increase of BLM, as well as in the popliteal lymph nodes of the opposite side. 2) L-BLM injected intralymphatically to the experimental group showed an effective concentration and remained in the regional lymph nodes for 4 to 5 weeks and a clear supressive effect of metastasis was found as compared with the non-injected group. 3) Histologic observation of the regional lymph nodes in the early stage after the injection showed oil droplets in the lymphonoduli and the surrounding tissues. Eosinophils and giant cells were found around the oil droplets in the lymphnoduli. These phenomena disappeared about 2 or 3 weeks after the injection. Histologic investigations of the other principal organs after the intralymphatic injection of L-BLM showed a normal structure. From the facts described above, it can be said that intralymphatic injection of L-BLM is a valuable method for the diagnosis and treatment of metastatic lymph nodes in the early stage.
This study concerns the research conducted on the biocompatibility of medical synthetic polymers utilized in the field of maxillo-facial surgery, such as Realastic®, Epithane-3®, HC-107/ON-105 system and Silastic® MDX4-4210. Three methods were used to evaluate the cytotoxicity to the L cell on each of these four polymers to investigate their biocompatibility. These three methods were 1) cell nucleus count, 2) morphological observation using a phase contrast microscope and 3) investigation of DNA, RNA and protein synthesis by the incorportion rate of radioactivity using 3H-thymidine, 3H-Uridine and 3H-Leucine. Results: Polmyer Cell nucleus count Morphology DNA, RNA and protein synthesis REALASTIC® Cytostatic in 1-10mg/ ml Cytostatic in 1-3.2mg/ml Cytocidal in 10mg/ml DNA, RNA and protein inhibited but RNA inhibition was moderate. EPITHANE-3® Cytostatic in 1mg/ml Cytocidal in 3.2-10mg/ml Cytostatic in 1mg/ml Cytocidal in 3.2-10mg/ml DNA, RNA and protein inhibited. HC-107/ON-105 system Cytostatic in 10-100mg/ml Cytostatic in10-100mg/ml DNA, RNA and protein inhibited. SILASTIC® MDX4-4210 Non-cytotoxicity in 10-100mg/ml Non-cytotoxici- DNA and RNA inhibited moderatety in 10-100mg ly but protein accelerated./ml Elution Tendency; By repeated extraction five times during 24 hours using a medium containing 10% serum, the decrease in the DNA synthesis inhibition of the L cell was measured and the following results were obtained: Realastic®; 100% Epithane-3®; 860, HC-107/ON-105 system; 36% and Silastic® MDX4-4210; 76% .
In three out of 288 cadavers for student laboratory practice, four elliptical bodies of rice size were found: one from the mandibular midline of a 61-year-old man, two from the right maxillary premolar region of an 80-year-old man and one from the left maxillary premolar region of a 65-year-old man. Histological examination revealed that these structures are composed of dentin and cementum, but deficient in enamel and surrounded by osteoid tissue. Comparison with the histological finding of the impacted supernumerary teeth and the remnants of the roots yielded the conclusion that these four bodies are regarded as enamelless tooth rudiments, the most reduced type of supernumerary teeth.
Arsenious acid was pasted on to the exposed dentine in the cats and the response of the pulp was investigated electrophysiologically and histopathologically. The results obtained were as follows: 1) The number of impulses per 20 minutes from the pulpal nerves reached the maximum in 2 to 6 hours after the application of arsenious acid, then decreased gradually and finally vanished in 14 to 21 hours. 2) Biphasic action potentials were recorded from the pulp by electrical stimulation of the inferior dental nerves. The amplitude of the first positive component and the latter negative component of the biphasic action potential decreased almost equally with time. 3) The histopathological changes of the pulp were preceded by the electrophysiological changes.
In order to investigate whether KMnO4, one of Calcergens, can be used in endodontic therapy, KMnO4was applied to the exposed pulp tissue of the rat molars and the reaction of the tissue was observed microscopically. The results obtained were as follows: 1) When a 0.02 M saline solution of KMnO4was applied, a moderate inflammation was observed on the surface of the exposed pulp as well as in the control. 2) When a 0.2 M saline solution of KMnO4was applied, the inflammatory reaction was stronger than in the control and a necrotic layer was often observed on the surface of the exposed pulp. 3) When the KMnO4powder was pasted on to the surface of the exposed pulp, the inflammatory reaction was stronger than in the control and a wide necrotic layer was observed on the surface of the exposed pulp and no dentin bridge formation was observed, on the contrary, when the Ca (OH) 2powder was applied, dentin bridge formation was observed.