THE STUDY ON THE PHYSICAL PROPERTY OF THE PERMANENT SOFT DENTURE LINERS / 대한치과보철학회지

This study was performed to evaluate the tensile bond strength and modulus of elasticity of three permanent soft denture liners (Molloplast B , Ufi Gel C , Tokuyama ) before and after thermocycling. And their water sorption were also evaluated. Each soft denture liner was bonded to PMMA denture base resin blocks and the tensile bond strength and modulus of elasticity were measured by using universal testing machine. For the water sorption, weight measured after immersion of soft denture liners in 37+/-1degrees C water bath for 4 weeks. The results were as follows : 1. Molloplast B had the highest tensile bond strength, while Tokuyama had the lowest tensile bond strength, There was no significant difference between Tokuyama and Molloplast B in the both nonthermocycling and thermocycling. There was significant difference in tensile strength of Tokuyama before and after thermocycling(p<0.05). 2. For the modulus of elasticity, there was no significant difference between Ufi Gel C and Tokuyama in the both nonthermocycling and thermocycling. There was significant difference in modulus of elasticity of Tokuyama before and after thermocycling(p<0.05). 3. The failure modes of Molloplast B and Ufi Gel C were nainley adhesive type and that of Tokuyama was mainly mixed type in case of nonthermocycling and cohesive type after thermocycling. 4. The water sorption of each soft liners was within+/-2% in times (p<0.05) but, there was no significant difference among the soft liners in times.

AN EVALUATION OF PRECISION FIT OF IMPLANT-SUPPORTED PROSTHESIS USING THE PERIOTEST / 대한치과보철학회지

In this study, the Periotest value was measured with Periotest to evaluate precision fit of the 2-unit and 3-unit implant-supported prosthesis by modifying the size and location of ill-fitted conditions. The 2-unit prosthesis was fabricated with the right implant fitted incorrectly and the 3-unit prosthesis with the right and center implant fitted incorrectly. To evaluate the effects of the ill-fitted sizes, 4 groups were divided.:The control group being the accurately fabricated sample group fitted properly. Group 1 was constructed with 40micrometer ill-fitted conditions, group 2 with 70micrometer and group 3 with 100micrometer ill-fitted conditions. The Periotest value was measured at each implant site after tightening 10Ncm. The result was follows: 1. The PTV on the ill-fitted area in the 2-unit implant-supported prosthesis increased as the ill-fitted conditions increased. There was a statistically significant difference among groups(p<0.05). In the same ill-fitted sample, the PTV depending on the measured location demonstrated a statistically significant difference (p<0.05). 2. The PTV on the ill-fitted area of the 3-unit implant-supported with an ill-fitted condition in the right implant increased as the ill-fitted conditions increased. There was a significant difference among groups (p<0.05). In the same ill-fitted sample, the PTV depending on the measured location demonstrated a statistically significant difference (p<0.05). 3. In the 3-unit implant-supported prosthesis with ill fitting conditions in the center implant, the PTV on the ill-fitted area demonstrated a statistically significant difference between the control group, group 1 and group 2 (p<0.05). In the same ill-fitted sample, the PTV depending on the measured location demonstrated significant difference between the gap side and the adjacent side with over 70micrometer ill-fitted conditions (p<0.05). The results suggest that Periotest is a valuable objective method for evaluating the precision fit of an implant superstructure.

ACCURACY OF FOUR ELASTOMERIC INTEROCCLUSAL RECORDING MATERIALS / 대한치과보철학회지

The purpose of this study is to evaluate the accuracy of four elastomeric interocclusal recording materials and the weight change according to different storage period (24 hours, 48hours, 7days) and different conditions (dry, wet). The techniques for establishing the intercuspal position were centic occlusion interocclusal record with four elastomeric interocclusal recording materials (Ramitec, Stat-BR, Blu-Mousse, Regisil) (experimental groups) and location of the cast in a position of maximum interdigitation using tactile and visual method(control group). To evaluate the accuracy of four elastomeric interocclusal recording materials, the quality of contacts between the mounted casts was compared with the results of an occlusal examination of the same subjects. The results were as follows : 1. The most accurate method of articulating study casts at the intercuspal position was by hand articulation and no significant differences in accuracy were observerd among the experimental groups. 2. In case of interocclusal records storaged in dry sealed plastic box, no significant differences in accuracy were observed among the experimental groups. 3. In case of interocclusal records storaged in water, there was significant inaccuracy in Ramitec group. 4. The biggest weight change was observed in Ramitec group in all storage conditions