PURPOSEThis study was performed to evaluate shear bond strength (SBS) between three dual-cured resin cements and silica coated zirconia, before and after thermocycling treatment.MATERIALS AND METHODSSixty specimens were cut in 15 × 2.75 mm discs using zirconia. After air blasting of 50 µm alumina, samples were prepared by tribochemical silica coating with Rocatec™ plus. The specimens were divided into three groups according to the dual-cure resin cement used: (1) Calibra silane+Calibra®, (2) Monobond S+Multilink® N and (3) ESPN sil+RelyX™ Unicem Clicker. After the resin cement was bonded to the zirconia using a Teflon mold, photopolymerization was carried out. Only 10 specimens in each group were thermocycled 6,000 times. Depending on thermocycling treatment, each group was divided into two subgroups (n=10) and SBS was measured by applying force at the speed of 1 mm/min using a universal testing machine. To find out the differences in SBS according to the types of cements and thermocycling using the SPSS, two-way ANOVA was conducted and post-hoc analysis was performed by Turkey's test.RESULTSIn non-thermal aged groups, SBS of Multilink group (M1) was higher than that of Calibra (C1) and Unicem (U1) group (P<.05). Moreover, even after thermocycling treatment, SBS of Multilink group (M2) was higher than the other groups (C2 and U2). All three cements showed lower SBS after the thermocycling than before the treatments. But Multilink and Unicem had a significant difference (P<.05).CONCLUSIONIn this experiment, Multilink showed the highest SBS before and after thermocycling. Also, bond strengths of all three cements decreased after thermocycling.

서론 현대의학의 발달과 의료기관에 대한 접근성이 향상되면서 65세 이상의 노인인구 비율은 10년 동안 약 4% 가량 증가하는 양상을 보이고 있다. 뿐만 아니라 85세 이상의 후기 노인인구 비율은 2000년에 노인인구의 5.09%를 차지했으나, 2010년에는 6.96%를 나타내며 빠르게 증가하고 있다. 이런 변화를 반영하 듯 의치 장착자의 비율 및 의치 필요율 역시 높은 비율을 보인 다. 이에 치과계는 완전 혹은 부분 무치악 환자의 의치 치료에 사용되는 재료 및 술식에 다각적인 접근을 통하여 환자의 상 황에 맞는 보철치료를 할 수 있도록 노력해야 한다. 의치의 사용에 대한 기록은 기원전 700년부터 나타나고 있 다. 나무, 뼈, 상아, 금속, 고무 등 다양한 재료가 무치악부의 대 체재로 사용되어져 왔으며, 1930년 Wright에 의해 폴리메틸메타 크릴레이트(Polymethylmethacrylate)가 개발되면서 다양한 종류의 폴리머들이 의치상의 재료로 소개되고 사용되었다. 1 그러나 methacrylate의 중합에 따른 수축은 해결되지 않았고, 이를 해결 하고자 사출성형술(injection molding technique)이 고안되었다. 이 방법을 적용하기 위해서는 보다 흐름성 있는 재료가 필요 하였고, 이는 탄성의치의 개발을 이끌었다. 1 1953년 개발된 nylon을 이용한 탄성의치재료인 polyamide는 의치 장착자에게서 기존의 치료방법을 보완할 수 있는 소재로서 무치악 환자 치 료의 지평을 넓혔다고 할 수 있다. 2,3Purpose: The purpose of this study was to compare the effect of 3 chairside polishing methods and laboratory polishing methods on surface roughness and C. albicans adhesion of polyamide denture base. Materials and methods: Using contact profilometer, the surface of polyamide specimens (25×15×2 mm) was studied after conventional polishing without finishing and after chiarside polishing with 2 chiarside polishing kits and chairside-pumice polishing following finishing with tungsten carbide bur. To evaluate the adhesion of C. albicans, C. albicans suspension was overlayed on the test specimen. And the specimens were incubated for 2 hours. Imprint culture method was achieved and counted the colony on the agar plate. Polished polyamide were evaluated using a scanning electron microscope. The statistics were conducted using one-way ANOVA and in case of difference, Scheffe test and Tamhane' s T2 test were used. Results: Surface roughness (Ra) of surfaces polished with 2 chairside polishing kits had higher than conventional polishing and pumice polishing. The highest roughness value was 0.32 ± 0.10 ㎛, and the lowest was 0.02 ± 0.00 ㎛. The adhesion of C. albicans on the specimens polished with chairside polishing group and pumice polishing group were increased than conventional polishing group (P<.01). Conclusion: Conventional laboratory polishing was found to produce the smoothest surface and the lowest adhesion of C. albicans. Two groups polished with Chairside polishing kits were similar with respect to surface roughness. Surface of the specimen polished with pumice is significantly smoother than 2 chairside polishing groups, but the result of C. albicans adhesion is that group polished with pumice was similar with 2 chairside polishing groups (P>.01). (J Korean Acad Prosthodont 2012;50:106-11)