Shigaku = Odontology; journal of Nihon Dental College最新文献

With the objective of making clear the oral health condition of chronic disable elderlies and thereby obtaining information for oral hygiene education and dental treatment, 77 elderlies in a special elderly nursing home attached to a private general hospital in Niigata Prefecture were studied by an interview/questionnaire method and dental examination. The following results were obtained. (1) Their mean age was 82.0 years. The major causes of chronic disability were diseases of the cerebral blood vessel and these diseases accounted for 54.5% of all diseases. The mean period of their chronic disability was 9 years. (2) 49.4% (38 persons) of them was edentulous, and 47.9% (18 persons) of them was using complete denture. (3) The average number of present teeth was 4.6 in all persons, while it was 9.0 in dentulous persons, and 3.3 of which were residual roots. (4) Salivary occult blood reaction test was positive in 87.2% in the dentulous persons and 34.2% in edentulous persons. (5) Simplified culture test using STOMASTAT was negative in 48.4% and positive in 51.6% of persons using a denture. (6) The above results indicated that dental diseases of chronic disable elderlies are not treated appropriately. This study revealed importance of dental examination, oral hygiene education and initial treatment in middle-aged and older persons.

Resultant products and gel substance, formed with silicahydro gel method as well as with freeze-drying silicahydro gel method by use of tray, were compared and examined to materialize clinical application of gel method easily and the following results were obtained: 1. Evaluation of gel substance in control group gel (silicahydro gel) and in experimental group gel (gel prepared by the addition of deionized water to freeze-drying silicahydro gel) As the results of measuring the estimation of F- by ion chromatography and pH value, no clear-cut distinction between control group gel and experimental group gel was recognized, however, it was implied by naked-eye observations and through scanning electron microscope with the passage of time that experimental group gel had been inferior to control group gel. 2. Evaluation of resultant products in control group gel (resultant products formed with silicahydro gel method) and in experimental group gel (resultant products formed with freeze-drying silicahydro gel method) Naked-eye observations of reacting progress, the pH measurements, the calculation of Ca/P ratio, qualitative analyses by X-ray diffraction (reference; the measurements of crystallite size, lattice imperfection and lattice constant) and composition analyses by infrared absorption spectrum were carried out and as the results, resultant products in control group gel proved to be more favorable than those in experimental group gel. From the foregoing outcomes, it was suggested that fluorapatite of favorable crystallinity had been possible to be produced more with silicahydro gel method than with freeze-drying silicahydro gel method, and that further investigation inclusive of gel substance would be required in the event of clinically applying freeze-drying silicahydro gel method effectively.

Hypophosphatasia is a hereditary disease characterized by congenital deficiency of tissue alkaline phosphatase. One of its dental features is the shedding of teeth. We have experienced a case which was referred to our clinic with the chief complaints of loss and shedding of lower deciduous central incisors and was diagnosed to be highly suspected of hypophosphatasia as a result of hematological examination at the pediatric clinic. As a result of close systemic and dental examination and further study of changes in the course for two and a half years, the following findings were obtained: 1. Low serum alkaline phosphatase level and hypercalcemia were the systemic findings of the disease. 2. There was no delayed ossification in terms of carpal bone age. 3. X-ray cephalography revealed no particular cephalic abnormality, except the lack of development of frontalis and mandibular. 4. Dental findings comprised marked resorption of upper alveolar bone in the front teeth area and pronounced instability of front deciduous teeth. 5. As for changes in oral symptoms, extraction of A because of pronounced instability was followed by spontaneous shedding of A. About one year later, A was extracted because of marked instability. At the time of this writing, A was slightly instable without any abnormality in the other teeth. 6. Pathohistological study of the extracted teeth disclosed only a little resorption of cement of root apex and dysgonic periodontium without any marked tissue changes.

This study was made to obtain the anterior reference point for determining the horizontal reference plane in prosthodontics for transferring the model in the natural head position of each patient onto the articulator in dental clinics. The results thus obtained are as follows: 1. Measuring points in the sitting and standing postures were located below the orbital point, respectively. 2. The natural head position tended to shift upward significantly more frequently in the standing posture than in the sitting posture. 3. The natural head position in the standing posture varied less and was more restorable than in the sitting posture. 4. The natural head position in the mirror-viewing method varied less and was more restorable than in two other methods. 5. Between the three reference points in the natural head position, the measurements based on the orbital point and the inner canthus of the eye showed less variance than the measurements based on the ala of the nose. 6. The ratios calculated from the measurements based on the reference points in the natural head position showed slightly more variance than the measurements based on the reference points. 7. From the above, it can be said that the point 23.3mm below the inner canthus of the eye, which was the average of measurements taken with the mirror-viewing method in the standing posture, may be appropriate for use as the anterior reference point for transferring the model in the natural head position of each patient onto the articulator.

The three-dimensional structure of the connective tissue core (CTC) of the four types of lingual papillae of the crab-eating macaque (Macaca fascicularis) was studied by scanning electron microscopy after removal of the epithelial cell layer by long-term treatment with hydrochloric acid at room temperature and compared with the results obtained from light microscopy. 1) Filiform papillae are densely distributed on the dorsal surface of the anterior two thirds of the tongue. Fungiform papillae are scattered among these filiform papillae, and are numerous at the anterior margin of the tongue. The connective tissue core of each filiform papilla looked like a lifting human hand with its palm towards the tongue tip. By using light microscopy, AF-positive elastic fibers were accumurated very densely just beneath the basal region of the anterior column epithelium of each filiform papilla. 2) CTC of fungiform papilla showed coralliform structure whose branches were ramified a few times. On the top of each branch there was a small depression where a taste bud was situated. 3) After removal of the epithelial cell layer of the foliate papilla, longitudinal grooves coinciding with the epithelial slits were observed. Some glandular ducts were seen protruding towards the exfoliated epithelium. 4) After removal of the covering epithelium of the vallate papilla, numerous small rod-shaped secondary CT cores appeared on the large primary CT core.

Ethylene oxide gas (EO gas) adsorbed onto sterilized objects was quantitated in an effort to take a safety measure against residual EO gas following its use in sterilization. We measured residual amounts of EO gas adsorbed onto laboratory wares, small medical tools and appliances just after post-sterilization airation to examine whether they were rendered entirely free from EO gas by the process. The results led us to arrive at the following conclusions: 1. EO gas was recognized to remain on sterilized objects even after allowing them to stand for about 16 hours following airation. 2. The amount of residual EO gas was smaller on metallic products and larger on rubber products (notably rubber gloves). An exceedingly high concentration of EO gas was noted to remain on a tooth-brush, among other plastic materials. These facts seem to indicate that the amount of residual EO gas is closely related to the texture and shape of materials to be sterilized. 3. As regards the potential toxicity of residual EO gas. However, their sensitivity was proved to be questionable, judgment on a result being subject to considerable individual variations. 4. Nevertheless, it is incontestable that these devices can at least provide a rough estimate of unavailing since monitoring by direct measurement of residual EO gas is virtually infeasible from a practical point of view.

The present study consists of a clinical and histopathological analysis of those cases which were diagnosed as multiple primary malignant neoplasms of the oral-maxillofacial region and the other organs. 9 patients of those multiple primary malignant neoplasms out of 261 patients of malignant neoplasms in the oral-maxillofacial region, who visited in out department from 1975 to 1986, were detected. 3.4% of the incidence rate was calculated. All the cases were male, and these included each 1 case of triple and quadruple. 7 cases were detected prior in the oral-maxillofacial region to the other organs. There seemed to be a preponderance to early detection of a neoplasm in the oral-maxillofacial region. Therefore, the possibility of multiple primary malignant neoplasms should be kept in mind in the routine clinical activities. 2 cases were synchronous, 6 months or less interval between the first and the second neoplasms, the others were metachronous, averaged 5-year interval. The primary sites in the oral-maxillofacial region were tongue (3 cases), floor of the mouth (2), buccal mucosa (2), lower gingiva (1), maxillary sinus (1), all of them were diagnosed as squamous cell carcinomas, histopathologically. The other organs were esophagus (3 cases), stomach (2), colon (2), lung (2), liver (1), urinary bladder (1), hypopharynx (1). Histopathological diagnoses of them were squamous cell carcinomas (3 cases of esophagus, each 1 case of lung, urinary bladder, and hypopharynx), adenocarcinomas (2 cases of stomach and colon, and 1 case of lung), and a hepatoma. It's necessary to differentiate the multiple primary malignant neoplasms from metastases when each of them were diagnosed as squamous cell carcinomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Search was made using quantification method of the first and second type to search the factors affecting the frequency of training, and to estimate it. The following conclusions were led; 1. Factors giving large effect on the decision of the frequency of training were 'Frankl classification', 'ages at the initial examination' and 'if children have any experience of dental treatment or not'. 2. With the factors concerned with educational environments including mothers, 'number of brothers and sisters', 'mother's educational history' and 'if mothers works or not' showed high correlation. 3. Among the factors concerned with character analysis, 'emotional stability' 'if children can control themselves or not' gave much effect. 4. As the factors to estimate the frequency of training, the reliable factors include 'Frankl classification', 'ages at initial examination', and 'sexes'. 5. With the factors concerned with educational environments including mothers, 'mother's educational history', 'number of brothers and sisters' 'birth order' were highly reliable. 6. With the factors concerned with character analysis, 'emotional stability', 'if children fants are degenerative or productive' showed high reliability. 7. Multiple correlation coefficient for all the 27 factors was 0.823, which was found to be highly reliable for the estimation of the frequency of training.

KB horizontal brackets were designed to tip no more than 6 degrees at the maximum. This tipping amount is based on the idea of reducing friction between a wire and brackets to allow the effective tooth movement of the Begg technique even with horizontally long brackets, and does not originate in the concept of carrying out tipping movement. Thereon, experimental measurements by use of Rheometer were conducted to review for comparison of the kinetic frictional forces caused between various wires and the following four types of brackets; KB horizontal brackets, Tip edge brackets, Straight edge brackets and Begg brackets. 1. In case of utilizing ribbon arch wires and rectangular wires, no significant difference was acknowledged among Tip edge, KB horizontal and Straight edge brackets. 2. There proved to be a reduction in the kinetic frictional forces by incorporating tip into the edgewise slots, when using smaller dimensions of the wires which call for the effective tooth movement, however, Begg brackets (in conjunction with Ordinary T-pins and/or Safety T-pins) showed the small value which is far less than that of the three kinds of brackets.

Recently, one of the major objectives was to observe cellular structures in biological-materials including microorganisms as raw as possible. For this purpose, Actinomyces israelii ATCC 12102, an experimented strain, was fixed by a fast freeze method using liquid nitrogen as a cryogen, followed by transmission electron microscopic observations on fine structures. Then, the following results were obtained. 1) Cell wall was an electron dense and thick monolayer. In certain cells, numerous granules were found on cell walls, showing lamellar structures. The cell wall surface to be a wave like structure of which limit was unclear. 2) Cytoplasmic membrane consisted of two electron less dense layers holding an electron dense layer in then. However, fine layers with different electron density crossed over one another, representing a formation of stripe structure in other cells. 3) In cytoplasm, we observed that fine fibers with high electron density crossed over fine fibers with low electron density. 4) We also observed that the specialized ring structure in cytoplasm.