Effects of activators contained in adhesives on dentin bond strengths / 대한치과보철학회지

STATEMENT OF PROBLEM: An incompatibility between the initiator systems of self-curing composite resins and light-curing adhesives was supposed recently. PURPOSE: The purpose of the study was to evaluate the influence of activators for self/dual bonding on dentin shear bonding strengths. MATERIAL AND METHODS: Fifty human molars were divided into 5 groups. A flat dentin surface was created for each tooth. A self-curing composite resin (Luxacore) was bonded with the following adhesives (n = 10): One-Step, Prime and Bond NT, AdheSE, Prime and Bond NT and AdheSe were also used in combination with activators. Shear bond strengths were measured after 24 hours of water storage. The specimens were loaded in shear in the Instron until failure at a 1 mm/min crosshead speed. Data were compared using one-way ANOVA and Tukey HSD test (alpha = 0.05). RESULTS: The dentin adhesive systems in order of decreasing median bond strength were One-Step > Prime & Bond NT with activator, AdheSe with activator > Prime and Bond NT, AdheSe. Among adhesives, One-Step had the highest bond strength. Prime & Bond NT with activator had higher bond strengths than Prime and Bond NT that was used alone, and so was AdheSe. CONCLUSION: Shear bond strengths were increased in Prime and Bond NT and AdheSe when these were used with activators comparing used without activators. But using activators was not effective clinically comparing One-Step.

A study on the prevalence of malocclusion of Yonsei university students in 1991 / 대한치과교정학회지

Over recent 20 years, with socioeconomic development and change of recognition of the population, more people are concerned about their health and appearance. To obtain the change of frequency of malocclusion and the demand for orthodontic treatment, with this trend, 2460 freshmen and students of Yonsei Univ. in 1991, aged from 18 to 21 were examined excluding 187 students who have history of orthodontic treatment, 86 students who are undergoing treat?ment, 39 students who have too much missing teeth to classify. After analize the frequency of malocclusion and the demand for orthodontic treatment, following results was obtained. 1. Sex ratio in the prevalence of malocclusion was 91.7%/90.8%, male to female, so there was no sex predilection. 2. With regard to Angle's Classification, each percentage of Class I, Class II div. 1, Class II div. 2 and Class III was 61.6%.11.3%,1.9% and 16.7%. 3. Of Class I malocclusion, percentage of crowding was 53.2, this occupied the largest part of single findings and prevalent findings in combinations were also crowding - crossbite and crowding - Protrusion. 4. Of Class I malocclusion, over the portion of 95%, Bialveolar Protrusion have arised alone. 5. The distribution of Demands for orthodontic treatment of malocclusion were 41.3% in males, and 51.3% in females.