Aichi Gakuin Daigaku Shigakkai shi最新文献

In order to investigate the density variance of casting dental alloys according to the change of temperature, a density measurement apparatus based on the sessile drop method was developed. This apparatus consisted of three parts: a furnace, a photo taking system and an image analyzing system. Five Ag-Cu binary alloys: Ag-3%Cu, Ag-15%Cu, Ag-28%Cu, Ag-70%Cu, Ag-97%Cu; were measured from room temperature to 1400 degrees C, and five graphs of Temperature-Density were drawn. From these graphs, densities, at room temperature, solidus point and liquidus point were obtained. Using this data, the solidifying shrinkage and the shrinkage in the solidus phase were calculated. The closer the composition of an alloy to pure metal the higher the solidifying shrinkage, and at the eutectic point the solidifying shrinkage showed the lowest value. It was observed that the metal texture influenced the value of solidifying shrinkage. There were no significant differences of thermal shrinkage in solidus between the five alloys, and each showed approximately 5vol% shrinkage. These values on high thermal condition are considered to be very important as fundamental data necessary for the manipulation of dental casting.

There are two different treatments for condyle neck fracture. One is non-surgical treatment involving intermaxillary fixation, and the other is radical surgical treatment through various techniques, but it is difficult to discuss the relative merits. The purpose of this report is to decide whether surgical treatment is necessary, by comparing the two types of treatment. In the period between April 1981 to December 1987, we treated 136 cases of condyle neck fracture at the Second Department of Oral and Maxillofacial Surgery School of Dentistry Aichigakuin University, and in 18 nearby hospitals. Of the 136 cases, 58 cases had fracture only at the condyle neck, while 78 cases had some concomittant fracture. As regards treatment, of the 136 cases, 49 (36%) were treated surgically, while 87 (64%) were treated non-surgically for condyle neck fracture. The surgically treated cases were divided into three groups: 24 cases were treated by pinning, 16 cases were treated by inter osseous wiring, and there were 9 other cases. In the treatment of concomittant fracture, 38 cases involved inter osseous wiring, 22 cases involved metal plate fixations, and there were 4 other cases. Non-surgical treatment accounted for 15 cases. The rate of surgical treatment for concomittant fracture was 82.1% of the cases treated. In surgically treated cases of condyle neck fracture, the mouth opening prognosis was generally poor. However, in these cases the deviation of mouth opening was generally better than in non-surgically treated cases. There were no differences in mastication, occlusion and pain in the TMJ region.

1. Cross-correlation analysis was made in the taste-sensitive neuron pairs recorded simultaneously from the parabrachial nucleus (PBN) of rats. Three indices were adopted to evaluate the activities of the taste neurons: 1) the spike response density (RD value), which is the net spike density with the 4 basic tastes. 2) the frequency of correlated discharges (FC value), which was determined by measuring the area of the peak appearing in the cross-correlogram (CC) during application of the test fluids. 3) the weight of correlated discharge (WC = FC/RD), which shows the relative importance of correlated discharges in the taste signals delivered by a component neuron of a given pair. 2. In 11 of the 23 pairs, the CCs exhibited peaks during stimulation with tastants. These 11 pairs, which were recorded in the pontine taste area, were composed of 18 NaCl-best (most sensitive to NaCl) and 4 HCl-best neurons. In 8 pairs, the best-taste of both of the component neurons was NaCl, and it was HCl in 1 pair (homo-type pairs). The remaining two pairs consisted of an NaCl-best and an HCl best neuron (hetero-type pairs). 3. In 8 homo-type pairs (7 NaCl-best and 1 HCl-best pair), each pair exhibited the maximal FC value during stimulation with the best-taste of the component neurons (2.3 less than or equal to maximal FC less than or equal to 26.6 Hz). In the remaining three pairs, the maximal FC values were low (0.8-1.9 Hz). Two of these pairs were hetero-type, and, in their cases, the maximal FC value was obtains during stimulation with a tastant which was different from the best-taste of the component neurons. 4. The peaks in the CCs usually straddled the origin, and their highest point was located at the origin or very close to it. The width of the peaks appearing in the CCs was broad (3-8 ms) in 7 pairs and narrow (0.5-2 ms) in 4 pairs. In all of the broad-peak pairs, the best-taste of both of the component neurons was identical (homo-type), NaCl or HCl. In six broad-peak pairs peaks also appeared during the application of distilled water. In the narrow-peak pairs, two were of homo-type (NaCl-best) and their maximal FC value was obtained during NaCl stimulation. Their maximal FC value was higher than that of the other two narrow-peak pairs, which were hetero-type and exhibited no peaks during water application.(ABSTRACT TRUNCATED AT 400 WORDS)

The patients who underwent reconstruction of cleft lip and palate had clinically abnormal characteristics such as cicatricial contracture in the cleft area, narrow arches, missing teeth, and fistula. Most of those patients showed severe class III malocclusion with underdevelopment of the maxillary complex. In such patients, the treatment objectives in orthodontics were mainly anterior and lateral expansions of the maxillary arches, and inhibition of mandibular growth. In recent years, the maxillary protractor has been used positively in the treatment of the underdeveloped maxillary complex. In this study, we report on two patients with cleft lip and palate, and underdevelopment of the maxillary complex. Maxillary protractors were used beneficially at the period of the dento-craniofacial growth spurt. In these two cases, improvement of disharmony was obtained in the antero-posterior relationship between the maxilla and the mandible. The effects of the treatment were forward movement of the maxilla and growth inhibition of the mandible. Accordingly, the use of the maxillary protractor for cleft lip and palate patients with underdeveloped maxilla at the period of the dento-craniofacial growth spurt was shown to be important.

Large doses of aspirin (200 mg/kg or 400 mg/kg, s.c) caused marked hypocalcemia in suckling rats, two hours after administration. The hypocalcemic effect was more evident in two week old rats than in one week old ones. Although the mechanism of aspirin-induced hypocalcemia is not clear at this moment, the drug can be a useful tool for inducing experimental hypocalcemia in suckling rats, besides hormonal and/or nutritional controls. In this report, large doses of aspirin were administrated to new born rats, once at one week after birth, or twice at one and two weeks after birth. The morphological changes of the lower incisor were examined using computer programs which have been developed for the analysis of plane curves such as the traces of the side view of the incisor. Aspirin administration shortened the length of the lower incisor and its labial trace. The width of the incisor, especially in the middle, was also diminished by aspirin administration. These observations suggest that the drug not only induced hypocalcemia in suckling rats but also to some extent suppressed the activity of odontoblasts which produce the dentin of the incisor. Analysis of curvature variance, calculated with the labial trace of the lower incisor, also suggested that large doses of aspirin had two effects. It suppressed mineralization of the teeth through its hypocalcemic effect, and it inhibited synthesis of the collagenous matrix. The computer programs applied in this study have proved useful in determining and analyzing morphological changes of bio-materials which are difficult to measure directly.

We have already reported that the maxillary was markedly contracted 1 month after a cleft palate operation. Since we thought that this was mainly attributable to cicatrized contraction of the operation region, we prepared a palatal plate and inserted it from an early stage after palate plasty. In this paper we present our summarized findings on the use of the palatal plate. We report on its use both immediately after the operation, and for a period of 3 months after the operation. Its use in both cases is intended to prevent maxillary contraction following surgical treatment of the cleft palate.

Unlabelled: We suspected that the composition of stiffened adhesive resins may cause adhesion bridges to drop out. In this study, by using a scanning type electron microscope, we observed the breaking sides of the adhesive resin after the tension test. We also examined the surfaces of the resin that we cut and ground after it had hardened, and the surfaces of the adhesion bridges that dropped out.

Results: 1) RESULTS of the tension test. No significant differences between the adhesive resins were observed. We noticed no significant differences between the metal surface treatment methods. 2) Observations of the breaking side after the tension test. When we examined Panavia EX, we observed flaking of the metallic side and the tooth enamel. We noticed that the surface was smooth regardless of the method of preprocessing the metal. But the surface of the adhesive resin was bumpy, and we found bubbles of different sizes on the resin surfaces. When we examined Super-Bond C&B, we observed flaking of the metallic side and the tooth enamel, and the surfaces were smooth regardless of the method of preprocessing the metal. Unlike Panavia EX, however, we found various hollows, big and small, like the bubbles on the smooth surfaces of Super-Bond C&B. 3) Observations of the abrasive surface of stiffened adhesive resins. With an ambient temperature of 15 and 28 degrees, we found many minute hollows like bubbles on the abrasive surfaces of Panavia EX and Super-Bond C&B. 4) Observations of the surface of the bonding materials of the adhesion bridges which dropped out. We found bumpy surfaces on the adhesive resin which remained on the metallic side of the adhesion bridges, whichever position the adhesion bridges dropped out of.

Matsumoto et al. have reported that the remineralization of rat incisor dentin following administration of various drugs depends upon the hematic calcium (hCa) level in parathyroidectomized (PTX) rats. It is known that injected lead according to a time marking method deposits at the mineralizing front in hard tissues. In the present study, we observed the alteration of the mineralizing front of the incisor dentin and examined the dependency of the dentin remineralization on the hCa level in PTX rats given 1,25 (OH)2D3. Male Wistar rats (7-8 weeks old) were used. They were fed a synthetic diet containing 0.3% Ca or 0.02% Ca (Ca-deficient) from 3 days before PTX. In order to mark the time in the incisor dentin, lead acetate was injected at 3 day intervals. Exp. I: A group of rats fed a diet containing 0.3% Ca was given a single injection (400 ng/kg) of 1,25 (OH)2D3 on the 9th day after PTX. Exp. II: four groups of rats were given daily injections of various doses (vehicle, 25, 50 and 100 ng/kg) of 1,25 (OH)2D3 from the 11th day after PTX for 13 days. The distance between the two lead-lines observed in the histological sections of the incisor was measured as an indicator of the appositional rate of dentin. In rats given a diet containing Ca below 0.3%, the hCa level was about 5 mg/dl after PTX. Mineralization of the incisor dentin was suppressed markedly, and a hematoxylin unstained zone was observed in the histological sections, indicating that the mineralizing front had been stagnant. In Exp I, a high dosage of 1,25 (OH)2D3 raised the hCa level to over 8 mg/dl within 12 hours; formation of a new mineralizing front and remineralization of the dentin were observed. In Exp. II, daily injections of 1.25 (OH)2D3 raised the hCa levels gradually and dose dependently. The hCa levels in groups of rats given 50 and 100 ng/kg of 1,25 (OH)2D3 were over 8 and 10 mg/dl respectively after the 6th day from the beginning of the drug administrations. The distance between the two lead-lines deposited in dentin also increased gradually. Therefore, the appositional rate of the incisor dentin seemed to increase in accordance with the rise in the hCa level. The correlation coefficient between the appositional rate of lingual dentin and the hCa level was estimated to be 0.922 (p less than 0.001, y = 4.4x + 19.2).(ABSTRACT TRUNCATED AT 400 WORDS)

The purpose of this study was to construct an evaluation chart to objectively and simply determine the extent of the masticatory function of complete denture wearers in daily clinical practice, and to describe the chart's clinical application. 58 different types of food were selected according to two criteria: their frequency of ingestion by complete denture wearers, and their convenience for determining the masticatory function. Then an anatomical artificial porcelain set of dentures was used to bite each food item, using only bicuspids and molars. Dentures were installed on an Instron Universal Testing Instrument to compression-cut the food. Food requiring the highest pressure was considered the hardest food. Then the masticatory function evaluation chart was constructed by using the hardness of the food as an index of relative masticatory difficulty. Using this chart, 95 complete denture wearers were tested to determine the masticatory function of their dentures. The following results were obtained: 1. The mean hardness of the 58 food items tested was 7.85 +/- 11.29 kg. The mean hardness of the 38 food items frequently ingested by complete denture wearers was 5.24 +/- 5.41 kg. 2. The differences in hardness of the foods tested were statistically processed, and the 58 food items were classified into 5 groups (I-V). This five-fold classification was used as a range for determining masticatory function. 3. A correlation coefficient of -0.697 (p less than 0.01) was found between the hardness of the food and the ease of eating the food. 4. A correlation coefficient of 0.548 (p less than 0.01) was found between the hardness of the food and the frequency of ingestion. 5. The masticatory function was determined on a 5-point scale from A to E according to the total number of food types that the subjects said that they could eat easily. The masticatory function increased progressively from A to E. The results of determining the masticatory function of the 95 complete denture wearers were as follows: Rank A 1.1%, B 10.5%, C 34.7%, D 29.5% and E 24.2%. 6. Persons who evaluated their own dentures positively comprised 86.0% of ranks D and E. On the other hand, persons who evaluated their own denture negatively were widely distributed from rank A through E, indicating that there were considerable individual differences. 7. It was concluded that the masticatory function evaluation chart was a reliable means of objectively and simply determining the masticatory function of complete denture wearers.