Clinical evaluation of 5 patients with implanted hydroxylapatite particles (Apaceram G^®) in defective bone following extirpation of upper or lower jaw cysts is reported in this paper. The particles were soaked in antibiotic solution before applying to the infected cysts. The prognosis was as follows; the shape of the alveolar process remained the same as it was preoperatively, the prostheses was applied to all patients from 2 to 3 months later, and no disturbances such as postoperative infection, ill healing of the wound or major loss of the hydroxylapatite were noted. In this series, the follow-up period is 12 to 15 months postoperatively. Therefore, long-term observation surrounding bone and soft tissues is important.

To investigate the effects of dexamethasone or indomethacin on bone cells, bone cells growing out of minced mice calvariae were used in vitro. These cell populations had an intensive alkaline phosphatase activity. Dexamethasone increased the incorporation of ³H-thymidine into DNA and had no affect on generation times. Indomethacin indicated a flat incorporation curve of ³H-thymidine with a delay in generation times. Indomethacin had a tendency to inhibit DNA synthesis.

On the other hand, when compared with the control group, ³H-proline incorporation increased at 6 from to 10 hrs with dexamethasone but with indomethacin it was later at 10 from to 24 hrs. These results suggest that dexamethasone stimulated DNA-synthesis of the osteogenic-progenitor cell was stimulated with dexamethasone, whereas indomethacin inhibited it. But ³H-proline incorporation treated with dexamethasone tended to increase at 6 hrs and 10 hrs. Indomethacin has lengthened the generation time and tended to delay ³H-proline incorporation.

On the basis of answers to questionnaires obtained from 71 dental clinics regarding instruments used in the disinfection and cleaning of the root canal, the disinfection and cleaning methods were examind with a scanning electron microscope and bacteria cultures.

The results were summarized as follows:

1. The disinfection procedures applied in dental clinics were found to be ineffective in preventing virus infection.

2. To remove the debris between the instrument blades during clinical practice, two methods-wiping off the debris with alcohol cotton and inserting the instrument into a sponge permeated with an antiseptic solution-were more effective than any other method.

3. Ultrasonic cleaning before disinfection, which was found to be in wide use among the dental clinics, was found to be an effective method to clean the debris.

4. It was confirmed that the combination of using a disinfectant and the ultrasonic apparatus shortened the disinfection time and considerably enhanced the disinfection effect. Obviously, a chemical solution effective in preventing virus infection should be applied in this procedure.

Occlusions in the infantile period were investigated using new criteria obatained from regular oral health examinations at Yahaba Town, Iwate Prefecture. The results are as follows; A comparatively high frequency of malocclusion 49.1% was recognized at low age, especially in 2-year-old children, during the final stage of eruption of deciduous teeth. Pathogenic factors of maloccltsions were mainly both type 1 and type 2 of discrepancy factor; other factors, as well as skeletal and functional factors were generally of a low frequency through the infantile period, except for the skeletal factor at 6 years of age, which was 13.9%. The severity of malocclusion was nearly 90% in grades A and B, but a few cases were diagnosed with more severe malocclusion in grade C.

As to making suggestion for oral health care from these findings, it seemed necessary that the food intake at the infantile stage should consist of more hard and fibrous material in order to compensate and accelerate maxillofacial bone growth. For treatment of malocclusions, it was considered that it is important to point out that this is the period to begin making correction of malocclusion.

Immunoglobulin G (lgG) and immunoglobulin M (IgM) antibodies were detected in human sera by an enzyme-linked immunosorbent assay (ELISA), using the type-specific antigens purified from polysaccharide, obtained from each type of group B streptpcocci (GBS).

The subjects were school children placed in an institution because of weak body condition or chronic diseases.

GBS were examined every month from March, 1985 to May, 1986. Sera were collected in April, June, and November, 1985, and again in March, 1986.

Type-specific IgG and IgM antibodies from GBS-isolated children were measured witk ELISA.

Only antibody types GBS-Ia, Ib, Ic, Ⅱ, and Ⅲ were recognized to be type specific.

Both levels of type-specific IgG and IgM antibodies from GBS-isolated children were significantly high compared with those from non GBS-isolated children.

Children who were GBS-isolated almost every month during the test period had relatively high levels of IgG and IgM antibodies. Just after GBS isolation, the IgM antibody level was higher than IgG. When GBS isolation was not noted, the levels of IgG and IgM antibodies were low.

These findings demonstrate that an ELISA was effective as a mesure for determination of IgM and IgG type-specific antibodies.

When trying to manage the development of occlusion for children with fusion and congenitally deficient deciduous teeth, it is necessary to know the basic forms of the crown and the dental arch. The objects of observation were 148 study models.

The results were as follows:

1. As to the mesiodistal diameter of the crowns of fused teeth, the incomplete types were significantly larger than the complete type and the difference was more than 1mm.

2. The LL/MD Index of the complete type of fusion was significantly smaller than all the teeth on the opposite side, therefore the external shape of the crown was thin.

3. In the case of lower deciduous lateral incisor and canine fusion the mesiodistal diameter of the central incisor crown at the fused side was significantly larger than those of the opposite side, especially in females.

4. The primary dental arch was distinctly narrow and small in the case of fused and congenitally deficient teeth. This was especially so in case of bilateral fusion of the lower lateral incisor and the canine.

5. The amount of the midline deviation was large in unilateral fusion cases, but there no differences were noted among the fused regions.

6. Frequency of appearance of different types in the terminal plane was the same as in normal cases.

7. The frequency of interdental spaces was high on the distal side of fusions of the lower and upper central and lateral incisors. The frequency was high on the mesiodistal sides of fused the lower lateral incisor and canine. But a low frequency of appearance was noted in the case of the fused lower lateral incisor and canine, in contrast to cases of fused lower central and lateral incisors, because their dental arches were significantly narrower and smaller.

A case of a fused tooth, the maxillary third molar and the supernumerary tooth, found in a 24-year-old female patient was reported. Macroscopically, the supernumerary tooth was fused to the mesiobuccal root surface of the maxillary third molar, and a shallow groove was noted on the crown of the supernumerary tooth. The histological finding of undecalcified ground sections revealed that the maxillary third molar and the supernumerary tooth were fused with dentin and cementum. It was thought that the supernumerary tooth was paramolar by its anatomical features, however, fusion between the third molar and paramolar is rare.

A case (10 years girl) of complex odontoma with epithelial hyperplasia showing a histological feature like the calcifying epithelial odontogenie tumor (CEOT) was reported. Hyperplastlc epithelial nests resembling parenchyma of CEOT were found in the lesion, i. e., hyperplastic epithelial nests were composed of polyhedral cells arranged in sheets and strands, and round calcific bodies with Liesegang ring-structure were scattered within the nests. Direct continuity between the hyperplastic epithelial nests with a histological feature of CEOT and an ameloblastic cell layer in close conatact with the enamel was noted. It was thought that the present hyperplaslic epithelial neste originated from the inner ameloblastic cell layer or stratum intermedium.

A case of complex odontoma with an interesting histopathological finding is reported. The patient was a 43-year-old woman. An x-ray examination revealed a hard tissue mass the size of pieon’s egg, in her right upper molar region. Histopathologically, the resected hard tissue mass was composed of fused tooth-like tissue and irregularly proliferated cementum-like tissue. Dentin foci with irregularly arranged tubuli were scattered in cementum-like tissue.