The purpose of the present study was to form of the stratum corneum from the isolated epithelial cells and to demonstrate morphological detail of keratinization. Epithelial cells and fibroblasts were isolated from a neonatal rat tongue. Adipocyte and pre-adipocyte were isolated from abdominal subcutaneous adipose tissue of the same rats. For cell culture, double walled chamber which was divided into upper and lower compartments was used. Isolated adipocyte and fibroblast were individually embedded in collagen gels and respectively laid on a membrane filter surface in the upper compartment. The epithelial cells were seeded at high densities on surface collagen gel layer. After 3 days of culture, the growth medium was removed in the upper compartment for exposure to air at only the epithelial cell layer. Maturation and vertical stratification of the epithelial cells occurred when they were exposed to air. These epithelial cells showed keratinization with the same morphology in vivo and demonstrated tonofilament accumulation and keratohyalin granules in the cytoplasm. When epithelial cells were seeded on collagen gel containing only fibroblasts and exposed to air, low grade keratinization of the epithelial cells occurred comparing with the culture on collagen gel layers containing both fibroblasts and adipocyte.
In conclusion, keratinization of epithelial cells in vitro occur in clear relation to mesenchymal cells and exposure to air.

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Effects of occlusal interference on blood pressure were examined in 47 unanaethetized rats. The occlusal interference was produced by insertion of unilateral bite-raising splints (1, 2 or 3 mm in vertical dimension). The splints were set on the upper teeth for 20 days. The systolic blood pressure was measured from the caudal artery by the tail-cuff method before, during and after insertion of the splints. The blood pressure of the 1 mm unilateral bite-raising group did not change significantly between before and during insertion of the splints. In the 2 and 3 mm bite-raising groups, the blood pressure during insertion of the splints increased significantly as compared with that before insertion of the splints; after removal of the splints, the increased blood pressure returned to the pre-insertion level. Reproducibility in the increase of blood pressure was observed when the insertion of the splints was applied repetitively. Unilateral bite-raising also produced a statistically significant reduction of body weight during insertion of the splints. However, when the effect of fasting on the blood pressure was examined, the blood pressure did not change significantly, whereas the body weight decreased remarkably during fasting. This indicates that the increase of blood pressure depends primarily on unilateral bite-raising. The results of the present study suggest that activation of the autonomic nervous system is involved in the increase of blood pressure induced by insertion of unilateral bite-raising splints, and that occlusal interference activates the autonomic nervous system as a stressor.

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To determine whether the sympathetic nervous system is involved in the increase of blood pressure induced by occlusal interference, the effects of adrenergic antagonists on blood pressure were examined in 22 male Wistar rats. Systolic blood pressure was measured by using the tail-cuff method. Prazosin (0.5 mg/kg, i.p.) and propranolol (1 mg/kg, i.p.) were used as α-and β-adrenergic antagonists, respectively. When a 3 mm unilateral bite-raising splint was applied for 20 days, the blood pressure during insertion of the splints increased significantly compared with that before insertion of the splints. However, the heart rate was not statistically significant between before and during insertion of the splints. The increased blood pressure, 143.1±6.6 mmHg, decreased significantly to 108.8±9.6 mmHg 1 h after the administration of prazosin. There was no statistically significant difference of heart rate between before and after administration of prazosin, although the heart rate increased from 333.6+29.2 to 377.6±22.1 bpm. Propranolol significantly reduced the blood pressure from 141.8±8.3 to 134.5±7.6 mmHg. The heart rate decreased from 323.6±15.8 to 294.8±34.0 bpm after administration; however, no statistically significant difference was observed. These results provide evidence that the increase of blood pressure induced by occlusal interference is mediated by activation of the sympathetic nervous system.

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Despite of perpetual object of attention, the question of functional roles on the formation of gnathic structures which might possibly develop into a major occlusal aberration has still remainel to be solved.
In seeking reasonable parameters for discriminating functional influences clearly the power spectrum analysis of surface electromyogram was found worth trying.
Then this study was initiated to investigate the effectiveness of the analysis when it was applied for the masseter and anterior temporal muscler respectively.
The parameters used in this study are Mean Power Frequency (MPF), Power spectrum pattern, and Masseter Total Power value per Temporalis Total Power value (M/T). The results we obtained were follows,
(1) In the subjects with normal occlusion, power spectrum indicates one or two peak form with relatively low frequency in MPF and M/T tends to more than 1.0.
(2) In the subjects with malocclusion, power spectrum pattern showed a band form with no peak, indicating relatively high frequency in MPF and under 1.0 in M/T in most cases.
(3) MPF seemed to be lower in the normal but higher in the malocclusion subjects. Moreover it was suggested that this parameter might be influenced by the type of the muscle fiber.
(4) M/T tended to be lower in the malocclusion indicates temporal dominance, but higher in the normal subjects. In addition, it was suggested this parameter might be influenced by the types of malocclusion and dent-facial morphology.
(5) It was concluded that these parameters of the power spectrum analysis from surface electromyogram could be one of the most effective measure to analyze functional intervention in the make-up of malocclusion.

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In intact anaesthetized rats, large myelinated afferent stimulation (LMAS) produced a decrease of discharge frequency in response of spinal cord dorsal horn neurons to noxious heating. In spinalized rats, in which the cervical cord (C2-C3 segments) was transected completely, LMAS failed to reduce the neuronal discharges in response to noxious heating. This result suggests that inhibition of nociceptive responses of dorsal horn neurons produced by LMAS is mediated via descending spinal pathways from supraspinal structures.

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The purpose of this study was to investigate the effects of taking impressions on the color of teeth. The color of the teeth was measured in the left maxillary central incisors of five subjects before and after the impression takings with a spectrophotometric colorimeter. One alginate and three elastomeric impression materials were used.
The results were as follows : (1) The L* values increased ; the a* and b* values decreased after dehydration with an air syringe.
(2) The L* values increased ; the a* and b* values decreased after the elastomeric impression takings.
(3) The L* values decreased ; the b* values increased, and the a* values scarcely varied after the alginate impression takings.
(4) The color differences between the pre-treatment and the post-impression teeth were influenced by the impression materials and by the various subjects used in this study.
(5) Some ΔE values between the pre-treatment and the post-impression teeth showed color differences detectable to the naked eye.
(6) The altered color of the teeth did not regain normal tooth color immediately.
(7) It is considered that the discoloration of the teeth was due to dehydration.
This study suggests that it is important to take into account the optimal conditions for shade taking in esthetic prosthetic and esthetic restorative dentistry.

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In this study the relationship between the surface roughness of abutments and the effect of the cement spacer was investigated. In study I, one to four layers of cement spacer were applied to four types of dies of different surface roughness. The surface roughness of the die and the film thickness of each layer were measured, In study II, rough surface roughness of prepared epoxy resin abutments and smooth surface roughness of polished epoxy resin abutments were used. The difference of surface roughness of the cement spacer applied to the dies and inner surface roughness of the full cast crowns was measured. The elevation of the full cast crowns before and after cementation measured. The results were as follows :
(1) The rough surface roughness of the dies became considerably smoother by application of the cement spacer, but the smooth surface roughness of the dies was scarcely changed.
(2) The film thickness of the cement spacer was not influenced by the surface of the dies.
(3) The inner surface roughness of the full cast crowns was not influenced by application of the cement spacer.
(4) The application of the cement spacer was found to decrease the elevation of the full cast crowns above the margin of the abutment.
(5) Compared with the rough surface roughness of the abutments, the smooth surface roughness of the abutments decreased the elevation of the full cast crowns.
In order to improve the fitting of the crown, smooth surface roughness and a cement spacer applied to the die is highly recommended.

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The purpose of this study was to determine statistical information concerning the crowns and the fixed partial dentures (total number, types and rate of crowns, number of vital or non-vital abutment teeth, etc.) made by the staff of the First Department of Prosthodontics, School of Dentistry, Showa University from April 1990 to March 1991.
The following results were obtained : (1) The total number of crowns and fixed partial dentures produced was 1149 ; among them 966 pieces (84%) were crown, and the other 183 pieces (16%) were fixed partial dentures.
(2) Most of the crowns were full cast crowns (496 pieces, 51. 3%); the second most commonly produced was the porcelain fused to metal crown (232 pieces, 24%).
(3) For the anterior teeth, there were as many porcelain fused to metal crowns used as there were jacket crowns. For the premolar teeth, there were twice as many full cast crowns as there were porcelain fused to metal crown. The full cast crown was used for almost all of the molar teeth.
(4) With regard to the fixed partial dentures, the mandibular posterior teeth were the most frequently treated ; next were the maxillary posterior teeth ; and the least frequently treated were the mandibular anterior teeth.
(5) Concerning the abutment teeth of the fixed partial dentures, 70% were non-vital teeth and 30% were vital.

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The purpose of this study was to elucidate morphological characteristics of the deciduous teeth of extremely low birth weight infants and very low birth weight infants. The subjects were 50 children of mean age of 4 years and zero month in generally good conditions with birth weights less than 1500 g. They had been treated by the Department of Pedodontics, School of Dentistry, Showa University.
The findings were as follows : (1) Analyzing the plaster models, average mesio-distal crown diameters were smaller than the normal value by 1SD for all kinds of deciduous teeth, average labio (bucco)lingual crown diameters were slightly smaller than for almost all kinds of teeth.
(2) As for the anomalies of shape, the fused teeth were found at a higher incidences (14. 0%) than in normal children.
(3) The incidence of enamel hypoplasia was 41 out of 50 subjects (82. 0%).
(4) Enamel hypoplasia teeth were observed more often in maxillary deciduous incisors, and enamel hypocalcification teeth were observed mainly in the maxillary and mandibular deciduous molars.
(5) Average microhardness of enamel was VHN (Vickers Hardness Number) 308. 4 and average microhardness of dentin was VHN 42. 9, which were lower than those of normal children.
(6) Based on light microscopic observation, the neonatal lines of the sample teeth were positioned closer to the incisal edge of teeth than in the case of the normal teeth and the Retzius line appeared more prominent in the sample teeth than in the normal teeth.

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The location of the landmark on the postero-anterior (PA) cephalogram changed by the rotation of the patient head. The geometrical error induced by the rotation will be simulated by using a personal computer. The human head was rotated +10° in vertical or horizontal direction. All positions of cephalometric landmarks on the radiogram were calculated in every degree of head position.
The results were follows : The error induced by the vertical rotation was larger than that of horizontal rotation. For instance, upper incisor (U1) was moved 31. 7 mm in vertical direction. The width of Gonions, and the length of Crista Galli (CG) to Menton (Me) were changed in 1. 27 mm, 2. 87 mm respectively. The angle of CG-Gonionl (Gol) to Gol-Me was changed 19. 22°. On the other hand, Ul was moved 31. 4 mm in horizontal direction. The width of Gonions, and the length of CG to Me were changed in 1. 51 mm, O. 10 mm respectively. The angle of CG-Gol to Gol-Me was changed 9.82°
The results indicate that the error of PA cephalogram was smaller in horizontal width (like Gol-Go2) than in vertical height (like CG-Me). The error in linear is generally smaller than that in angular.

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The growth patterns of the cephalometrical measurement show possible phased changes in some groups. In this report, phased growth patterns are searched on the aboriginals in Taiwan.
The cephalometries are carried out on the aboriginal and Chinese children from 6 to 15 years old in Taiwan, namely the Paiwan, Ami, Bunun, Atayal and Chinese from middle China.
Differences between annual measurements are shown in the charts as the dots. The lacks of dots for three or more years are decided as a phased retardation of growth. The comparisons of the charts reveal the following results.
The phased growths of cephalic breadth are revealed in the all inquired groups and those of cephalic length are shown in about half of the groups. In the facial measurements, any phased growth patterns are not detected. Phased patterns show mainly two step growths but three step growth patterns are scarce.
There is no sexuality on the appearances of phased patterns. Phased growth patterns on cephalic measurements are common in all the groups, but facial measurements do not show any phased growth patterns. A study of the phased growth patten requires a most precise measurement.

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