The auther studied the open-bite of Hellman dental age IIIC groups of Korean childern on the roentgenocephalometry. The subjects consisted of 45 males and 45 females with normal occlusion and acceptable profile. The major conclusions may be listed as follows: 1. This study was summerized in the form of tables, mean, standard deviation, minium and maximum for 35 angular, linear and ration measurements. 2. Charts of standard deviation from the mesurements were made for the clinical application.

Sixty six mandibular incisor were injected with China ink, decalcified, cleared and used to study the number of root canals, the frequency and location of lateral canals, the location of apical foramens, the frequency of apical deltas, and the curvature of root canals. The results were as follows: 1. Most of the teeth demonstrated single canal, but 19.7% of the teeth were found to have bifurcated canals. 2. 12% of the teeth were found to have lateral canals and these ramifications were located in the apical third of the root. 3. 25 apical foramens were located directly on the root apex and 41 foramens laterally. 4. 43 canals showed straight, 7 canals distal curvature, 7 labial curvature, 3 mesial curvature.

The purpose of this study was to evaluate the marginal sealing ability of 'Hi-Pol' Enamel Bond system. Using freshly extracted human teeth and 2% acquous methylene blue, the marginal leakage of dye in restorative materials such as 'Hi-Pol' Enamel Bond system, Hi-Pol, Adaptic, Nuva system, Epolite and Amalgam were investigated at 37℃ and under temperature cycling in range of 4℃-60℃. the results as follows; 1. All filling materials showed some degree of marginal penetration by 2% methylene blue dye. 2. 'Hi-Pol' Enamel Bond system revealed the least marginal penetration by 2% methylene blue as Nuva did at 37℃, but under temperature cycling in range of 4℃-60℃ it showed the greatest marginal penetration. 3. Hi-Pol restoration showed a tendency the similar to the other composite restoration. 4. Nuva system had the most effective marginal sealing ability either at 37℃ and under temperature cycling.

The author studied skin reactions and their incidences among 100 dental students and dental nurses to 2% Lidocaine HC1, 3% H₂O₂, Euginol, 5% Sodium Hypochlorite, Dycal and Adhesive plaster by means of Patch test. Following are the results of the study. 1. Eighty six cases out of 100 revealed slight response to 1 or 2 allergens. 2. 2% Lidocaine HC1 showed 1 case, 3% H₂O₂cases, Euginol 2 cases, 5% Sodium Hypochlorite 74 cases, Dycal 1 case Adhesive plaster 8 cases. 3. 5% Sodium Hypochlorite was the most influential to skin. 32 cases showed grade 1+, 20 cases showed grade 2++, 16 cases showed grade 3+++, 6 cases showed grade 4++++,

The auther had examined the periodontal tissues of 273 nurses and students of nursing school in National Medical Center. the obtained results were as follows; 1. The ppevalence rate of the periodontal disease was 87.55% on the average in Korean women who are in the twenties. 2. The prevalence rates of the periodontal disease of the old women were highre than that of young women.