120 watt continuous wave solar-pumped laser with a liquid light-guide lens and an Nd:YAG rod.

We propose a simple and efficient pumping approach for a high-power solar-pumped laser by using a liquid light-guide lens (LLGL) and a hybrid pumping cavity. A 2×2 m Fresnel lens is used as a primary concentrator to collect natural sunlight; 120 W cw laser power and a 4.3% total slope efficiency are achieved with a 6-mm diameter Nd:YAG rod within a 14-mm diameter LLGL. The corresponded collection efficiency is 30.0 W/m(2), which is 1.5 times larger than the previous record. This result is unexpectedly better than that of Cr:Nd:YAG ceramics. It is because the scattering coefficient of Cr:Nd:YAG ceramics is 0.004cm(1), which is 2 times larger than that of the Nd:YAG crystal, although both have similar saturation gains.

Inverted impaction of second premolar: two case reports.

This report documents two patients with inversion and impaction of the second premolar tooth. Family and personal histories of both patients were unremarkable with no abnormalities in general growth and development nor any history of trauma. Patient 1 was a 10-year-old female with inversion and impaction of the mandibular right second premolar. Fifteen months previously, pre-operative radiographic examination prior to extraction of the mandibular right second primary molar revealed a normal direction and eruptive pattern of the tooth in question. However, following extraction of the mandibular right second primary molar, the developing succedaneous premolar was seen to be inverted. This was suggestive of inversion resulting from an iatrogenic force during tooth extraction. The second patient was a 9-year-old male with inversion and impaction of the maxillary right second premolar. Radiographic examination 3 months prior to the initial visit at our hospital showed an existing inversion of this tooth. This pointed to a developmental abnormality in the location of the original tooth bud.

[An epidemiological study on dental caries of children in the town of Fuji. 3. Correlation between dental caries and personality characteristics].

A statistical study was carried out to evaluate the dental caries of permanent teeth in the elementary school children (208 boys and 165 girls, 373 children of total) in the town of Fuji, Saga Prefectur, which is a mountain village, by means of psychological test and investigation of the living environment of children and their parents. The following results were obtained: 1. In analysis of the relationship between the increase of dental caries and personality characteristics, was shown a tendency toward a low degree of direct of correlation. However, in analysis of quantification type III, it was proven that personality characteristics that as dependency, regression, nervousness and emotional instability related to an increase in dental caries. 2. In the analysis of the relationship between living environments and personality characteristics, a tendency towards a low personality profile was recognized in the children with an increase of dental caries. 3. In pasticvcal, there was a distortion of the personality characteristics of slef-uncontrol and dependency. 4. In comparing the first half of the elementary school year with the last half, a difference in the living environment and personality characteristics was observed during the last half year. 5. The results obtained in this study indicated that early discovery of problems in the living environment and synthetic approach during the first half of the elementary school year were important for the prevention of dental caries of permanent teeth.

[An epidemiological study on dental caries of children in the town of Fuji].

An epidemiological investigation of dental caries was undertaken during the period of 1987-1989 with all children of nursery school, kindergarten, elementary and junior high school age in the town of Fuji, Saga prefecture which is a mountain villate, experiencing little movement of the population. From this investigation the following results were obtained. 1. Although the number of the children in each age group who had dental caries in deciduous and permanent teeth appeared to have decreased compared with 1987 and 1989, the dental caries prevalence in the children still remained high. 2. It appeared that it was important to give dental health education during the stage of immature young permanent teeth since there was prior to evidence of high dental caries in this stage. 3. The following was suggested for the improvement of caries experienced in immature young permanent teeth in the school in Fuji: (1) no stock of soft drinks in the refrigerator, (2) guardian's strict supervision of their children concerning snacks and, (3) acquiring of the habit of brushing during infancy and preschool years with parental assistance.

[An epidemiological study on dental caries of children in Fuji town. 1. Prevalence of dental caries].

An epidemiological investigation on dental caries was undertaken with 810 children of nursery school, kindergarten, elementary and junior high school age in the town of Fuji, saga prefecture which is a mountain village with less movement of the population. From this investigation the following results were obtained regarding the dental caries prevalence and the status of treatment: 1. As for the dental caries prevalence of deciduous teeth, the dft index was 8.8 at age 3, whereas it was 10.7 at age 5. 2. As for the dental caries prevalence of the permanent teeth, the DMFT value was 7.7 at age 12, whereas it was 9.9 at age 14. 3. As for differences based on set, concerning the deciduous teeth, none was not recognized except for the caries prevalence indices at age 11 for the dft index, at age 6 and 11 for the dfs index, and at age 11 for the ft index. 4. As for differences based on sex, concerning the permanent teeth, none was not recognized except for the caries prevalence indices at age 5 and 9 for the DFT and DFS indices, and at 7 for the FT and F tooth rate. 5. There was a tendency toward as significant increase in dental caries in the deciduous teeth. 6. There was a tendency toward as increase in dental caries in permanent teeth from the commencement of eruption and rapid aggravation approximately from the upper grades of elementary school. 7. In the status of treatment of dental caries in deciduous teeth, the ft index was 4.1 at age 6. 8. In the status of treatment of dental caries in permanent teeth, the FT index was 4.5 at age 14. 9. There was no statistically significant difference among kindergarten and nursery school children except for the dft and dfs indices at age 4.