Until recently porcelain fused to metal had been solely imported goods. Being developed by some Japanese mades, however, a few kinds of porcelain for fused to metal are now available in the market, Therfore, measurement of the bending strength, hardness and thermal expansion were made in three kinds of domestic made porcelain (UNIBOND, METALBOND and CERACHROME) and the clinically acknowledged foreign made VMK68.

The comparative investigation of their results led to the following conclusions.

1) Bending strength: VMK68, opaque colour porcelain was 1,080kg/cm² and the other kinds UNIBOND and METALBOND were almost eqally strong being 1,120 kg/cm² and 1,060 kg/cm² each opaque colour. CERACHROME opaque colour was 860kg/cm² that was inferior to the three kinds beforementioned. VMK68, UNIBOND, and METALBOND, dentin colour and enamel colour porcelain were inferior to opaque colour, CERACHROME enamel colour was strong to opaque colour and dentin colour porcelain.

2) Hardness: There was no obvious difference in the hardness of these porcelain, opaque colour and enamel colour porcelain were nearly 520Hv, dentin colour porcelain was around 500Hv. It was harder than natural enamel which was approximately 400 Hv.

3) In any porcelain the thermal expansion of opaque colour porcelain was the greatest, dentin colour and enamel colour porcelain were compared with that of the opaque colour was 0.2-0.5% lower.

4) In any porcelain the thermal expansion was smaller than that of metal alloy (KIK) within the range of temperature lower than the transformation point. At temperatures higher than the trnsfomation point, however, porcelain showed greater expansion than the alloy.

5) In the investigation of the physical properties of porcelain fused, VMK68 showed the most favourable results. Whwereas UNIBOND results showed as good as those of VMK68 and CERACHROME, and METALBOND suggested to have some problems.

The authors studied a statistical survey of the autopsy cases of the malignant laryngeal tumor (MLT), which were collected from the annuals of the pathological autopsy cases in Japan during five years from 1972 to 1976, in order to examine the actual condition of the MLT in Japan.

The total number of 363 cases of the MLT (Male: 326, Female: 35, Unknown: 2) were revealed, and the average age of the cases was 65. 0 years old (Male: 64.8, Female: 665). Histopathologically, 318 cases showed squamous cell carcinoma. About the age distribution at autopsy, 144 cases were in seventh decade. Multiple primary cancers affecting both the larynx and the other organs were found in 65 cases (double: 60, triple: 5).

The unit activities elicited by electrical stimulation of the tooth pulp of the canines and molars were recorded in somatosensory area Ⅲ (S_Ⅲ). The firing properties and the receptive fields of the single neurons were mainly studied. The neurons recorded were classified into two types by their responses. Type I was characterized by well-synchronized initial spikes of short latencies (5-15 msec.). Type Ⅱ was categorized by the less-synchronized initial bursts of long latencies (10-50 msec.) followed by prolonged after-discharges. They were responded not only to pulpal stimulus but also to other types of stimulation such as mechanical stimuli applied to periodontal tissue, lips and facial skin. Although a few exceptional cells were found, most of the cells were excited bilaterally. The pulp-driven population was divided into several functional subsets; those excited from one pulp only (mono-tooth type) and those excited from more than one pulp (multi-teeth type). The population of the former type was relatively higher (38%) than the later. The canine-molar dominancy shows a prevalence to molar innervation compared with the canine one. It was discussed that the functional role of the mono-tooth type neurons seems to be capable of localizing pulpal stimuli.

The purpose of this study was made to discriminate the premature contact tooth from the aspect of the occlusal sound.

Acouple of transducer (ceramic type microphone) was placed on the both side of temple region.

a) 1,000Hz vibration was directly applied to the each tooth of maxilla, and the propagation-time-difference of signals were measured.

b) Occlusal sounds from premature contact using the tooth crown on the maxillary dental arch were received and the same measurements were done.

The measured propagation-time-differences of a) and b) were nearly equal. From these results, it suggest that the premature contact tooth is detected from the occlusal sound.

On the observation and the measurement of microcirculation, there are many me-thods. Recently, it is often used that the cast is taken by means of injection of acrylic resin and is observed by scanning electron microscope. However, there was only a little report con-cerning the validity of the measurment of microvessels. Therefore, in this study, jejunum of a rat was used. This study was attemped to examine the difference between the cast and the other methods (capillary microscope, electron Inicroscope, Indian ink injection and microangiogram).

In addition to the microvascular system of the rat’s jejunum was obscrved on the cast.

Results were as follows:

1.Colnpared with the other methods except microangiogram, it almost regards the diameters of vessels which were measured on the cast in the approximate value with them. The cast can be very useful method at the measurment.

2.The vascular system of the rat’s jejunum is useful for the purpose of absorption, secretion and control of the amount of the following blood easily.

One hundred and thirty five human complete impacted third molars were used. In this experiment, some acids were used, which were (1N,0.5N,0.01N) acetic acid, (0.01N,0.001N) hydrochloric acid and (0.1N,0.01N,37%,50%) phosphoric acid. The etched ena-mel surface treated with these acids were observed by scanning electron microscope, and were measured the depth of etched surface by the stereoscope.

The results were as follows.

1) From the effects of the various acids, four patterns were observed on the etched enamel surface. Pattern I : Peeled off the layer of the surface of enamel. Pattern Ⅱ : The center of the enamel rod was depressed. Pattern Ⅲ : The border of enamel rod was depressed. Pattern Ⅳ : Mixed with pattern Ⅱ and pattern Ⅲ.

2) Regardless of the kinds of acid, the depth of dissolved enamel decrease with increasing lower pH and treated time.

3) On the quantity of ething of enamel surface, the effect of acetic acid (organic acid) were weakly. It seemed that organic acid has aspecific characteristics compared with inorganic acid.

Reconstruction of the lnandible was performed through bone grafting fbllowing ma-ndibular resection in five patients with extensive ameloblastoma. Because of unsatisfactory results due to infection, fracture of the graft and pseudoarthrosis formation, reconstructions were attempted employing a graft from a rib, ilium or the lower border of the mandible. As a result, the con-tour and function of the mandible improved and dentures were successfully applied over a period of 20 or 3 years. In this paper, the causes and procedures of the unsatisfactory results following mandibular reconstructtion are discussed.

The inhibitory effect of chlorpromazine (CPZ) on pilocarpine-induced salivary res-ponse in mice was examined to determine the effect of single and repeated administration of CPZ. The experiment was carried out by the method of Richter, using urethane anesthetized mice. Single administration of CPZ (2,4,8and 40mg/kg, s. c.) inhibited clearly pilocarpine (1.25 mg/kg, s. c.) -induced salivary response. However, this inhibitory effect of CPZ was remarkably weak in comparison with that of atropine and did not exceed 50 per cent even when 40 mg/kg of CPZ was administered. When a fixed dose of 40r 40 mg/kg of CPZ was administered once daily for 21 days, the effect of 4 mg/kg of CPZ on 7 th,14th and 21th days decreased as com・ pared with the level of the initial effect. On the other hand, the effect of 40 mg/kg of CPZ was constantly maintained the level of the initial effect for 21 days. These results show that CPZ can inhibit the salivary function of salivary glands in mice, and tolerance to CPZ develops when a small dose of CPZ is repeatedly administered.