리튬 다이실리케이트 세라믹을 이용한 CAD/CAM용 컴포짓 레진 블록의 제조

Abstract

Fabrication of composite resin blocks by combining high strength of ceramic fillers with excellent fracture toughness of resin matrix, which can be applied to CAD/CAM restoration was investigated in this study. Ceramic fillers were heat-treated quenched glasses in order to crystallize the lithium disilicate phase, then milled into average size of 3.4 μm and subsequently silanated. They were mixed with resin matrix, which was prepared by mixing TEGDMA into Bis-GMA with weight ratio of 4:6 with benzoyl peroxide as a thermal curing initiator as well butylated hydroxytoluene as a polymerization inhibitor, and thermal cured into blocks. Flexural strength, cured depth, water sorption, solubility, radio-opacity, distortion, cracking, porosity, blanching were determined according to international standard ISO 4049 Dentistry-Polymer-based restorative materials, ISO 6872 Dentistry-Ceramic materials, and ISO 22112 Dentistry-Artificial teeth for dental prostheses. Flexural strength of the fillers increased after crystallization in all composition and reached maximum 323.0 MPa with addition of BaO, MgO, CaO and Al2O3. The optimum allowance of the thermal curing initiator was 0.3 wt% cosidering stability in shelf, though the flexural strength of resin matrix was increased with increasing thermal curing initiator. The optimal thermal curing condition was 80℃ for 12 hrs due to distortion and cracking when cured at higher temperature for longer time. Flexural strength of the composite resin block was increased with increasing the content of the filler, then reached 198.0 MPa at 70 wt%. The fabricated composite resin block is expected to be CAD/CAM block in dental resotration.