Twenty five cases of operation materials of the human tongue were studied histopathologically by serial sections, with particular attention to the occurrence of cartilaginous tissues. As a result, a small mass of cartilaginous tissue was found in the septum linguae of one case. This cartilaginous tissue was surrounded by a perichondrium-like thin fibrous connective tissue. Several special stains and ultrastructural examination indicated that the cartilaginous tissue found in the present study was elastic one, however, its histological architecture was irregular markedly.

In addition to the above findings, the histogenesis of cartilaginous tissue in the septum linguae of the human tongue was discussed embryologically and phylogenetically.

The effect of single traumatic injury on rat incisor enamel was investigated histiopathologically. Twelve male mature Wistar’s rats were used in this experiment. Lower bilateral incisors of each rat were fractured completely by dental forceps. The animals were sacrificed 3, 4, 5, 7 and 10 days later. The mamdibles were removed, fixed, demineralized, embedded in paraffin and prepared for histopatholgical examination in the routine manner. The results were as follows: 1)Maldevelopment of amelogenesis was found in three of twelve cases (5, 7 and 10 days after fracture). 2)Maldevelopment of amelogenesis was classified into two patterns. The first was localized deposition of immature enamel, which showed globular or wavy in shape, between regular-formed enamel and ameloblastic layers. The other pattern was localized enamel hypoplasia in maked degree. 3)It was thought that the maldevelopment of amelogenesis found in the present study was caused by the disturbance of amelogenesis of ameloblasts due to indirect traumatic injury.

The purpose of the present study was to investigate and to compare clinicopathological findings on capillary hemangioma (CPH) and cavernous hemangioma (CVH) of the human tongue. The materials used were biopsy specimens of the tongue dealed with in the division of pathology, central clinical laboratory, and in the department of oral pathology, school of dentistry, during the past ten years (1971-1980). The following findings were obtained.

1. There was little difference noted in the incidence of CPH and CVH between male and female.

2. Mean age on first recognition of the tumor was 51.7土16.4 years in the CPH group and 29.9土23.0 years in the CVH group, being significantly younger in the latter (P<0.05). The mean age on consultation to the hospital was 51.3土18.2 years in the CPH group and 28.5土19.6 years in the CVH group.

3. Tumor formation represented the chief complaint in an overwhelming majority in both the CPH and the CVH groups.

4. The CPH tended to be located in the relatively anterior part of the tongue, whereas CVH was seen all over the tongue.

5. The interval between subjective recognition of the hemangioma and consultation to the hospital (suffering duration) ranged between 1 and 18 months in many cases of the CPH group. In the CVH group, this interval was less than 3 months in some cases, and 2 to 8 years in others.

6. The size of the hemangioma was apparently unrelated to the division between the CPH and the CVH group.

7. In the macroscopic findings, pedunculated and sessile hemangiome were found in almost equal in number in all cases investigated in the CPH group, whereas sessile hemangiomas were predominant in the CVH group.

8. The surface of the hemangioma showed ulceration in many cases of the CPH group, while ulceration was quite rare in the CVH group.

9. Inflmmatory cell infiltration was seen in both the CPH and the CVH groups, There was no indication of severe cell infiltration in the CVH group.

10. Although CPH and CVH of the tongue have frequently been discussed togethor, the present results indicated that in many aspects the characteristics of CPH and CVH are different, therefore it may be assumed that the causes and histogenesis of these two kinds of hemangioma are also probably different.

The purpose of this paper is to clarify morphological changes of the reticuloendothelial cells in the spleen following X-irradiation by Katsura’s silver impregnation method.

The animals used in this experiment were ddN female mice weighing 20 to 25g. The mice were given X-irradiation to the total-head (1,500R) or whole body (300R).

The metallophilic cells in the spleen of control mice were of the small foamy type in the follicle, the large stellate type in the marginal metallophils, the small branching type in the marginal zone and the small foamy or round type in the red pulp, respectively.

The metallophilic cells decreased immediately after whole body irradiation and the number of cells returned to normal in from 10 to 14 days.

On the other hand, the number of the metallophilic cells in the follicle and the perifollicular region increased immediately after total-head X-irradiation. This state continued for several days.

In the marginal zone and red pulp, the number of amoebian type cells appeared from 24 hours after irradiation and the numder of cells in total-head irradiation group were more clearly distinguishable than in the whole body irradiated group.

Previously, we reported about an approach to the improvement of oral hygiene of handicapped children and gave an estimate of their oral hygiene and gingival condition. In this study, we report a system of dental treatment and the oral condition of handicapped children.

1) Dental treatment is done after tooth brushing instruction has been given. As to the practical treatment or management of handicapped children, no special methods or equipment were used.

2) The rate of decay of deciduous teeth was 58.4% and of permanent teeth was 13.7%. The rate of treatment of deciduous teeth was 44.1% and of permanent teeth was 8.9%.

3) From 1974 to 1981, there was nogreat improvement on rate of tooth decay but treatment of tooth decay had improved.

4) The rate of tooth decay in children with cerebral palsy and treatment of their teeth was lower than that of children with other diseases.

It has been known that the chemical strengthening method of the low temperature type by KNO₃ molten salt effectivly increases the strength of porcelain material The method was applied to porcelain teeth for the purpose of increasing their strength. In the present study, the strength was measured and investigated by 45 degree breakage test and by repeat impact test. The results were as follows:

The strongest porcelain tooth was obtained when treated at a temperature of 500°C for 5-7.5 hours in KNO₃ molten salt, but did not when treated under any other condition.

The integral absorbed dose in panoramic tomography (70kVp, 0.8mA) and in conventional full mouth radiography (65kVp, 7.5mA) by means of the film method is reported.

The results are as follows;

1)in panoramic tomography: 98g・rad per film

2)in full mouth radiography: 37g・rad average per film

There are many reports about the integral absorbed dose but each method of arriving at an integral dose is not same and there are several variations in the experimental conditions.

A comparison of the results is difficult.

An autopsy case of malignant fibrous histiocytoma originated from the maxilla was reported. The patient was a 73-year-old Japanease female who had been suffering from maxillary tumor for 3 years and 3 months. Autopsy revealed marked direct extension of the tumor, and multiple metastatic lesions in both lungs and pleuritis carcinomatosa were found. Other findings included a slight degree of general hemorrhagic diathesis, concentric hypertrophy of the left ventricle of the heart and an islet cell tumor of the pancreas. The direct cause of her death was respiratory disturbance due to a metastatic tumor of the lungs. Histopathologically, proliferation of atypical tumor cells of various-size and shape, i. e. spindle-shaped fibroblastic cells, histiocytic cells, and bizarre multinucleated giant cells with frequent phagocytotic activity were noted. An irregular storiform pattern was also found in part. Furthermore, electron microscopical and histochemical studies of this case were performed.

In a 19 year-old female, we found a supernumerary permanent tooth, a mandibular incisor, with a fully developed clinical crown. It was located on the dental arch, between the right lower central incisor and the canine. A periapical radiograph revealed a fully developed root.

The result of histopathological examination of biopsy, operation and autopsy materials, in our histopathology laboratory in 1982, was introduced briefly. The total number of specimens examined, offered from our dental hospital, was 483 (cysts, 27.1%; tumors, 26.9%; inflammatory diseases, 21.5%; tumor-like lesions, 3.1%; others, 21.3%). Autopsy was performed in 5 of expired cases. The number of specimens examined, offered from the medical hospital and other dental clinics, was 43.

In addition to the result of examining the above-mentioned materials, difference of laboratory characteristics between the dental hospital and the medical hospital is discussed.