2022 Volume 42 Issue 1 Pages 38-52
The objective of this study was to examine the characteristics of four commercially available resin composite blocks for CAD/CAM crowns of anterior teeth [Cerasmart Layer (CL),Katana Avencia N(AN),KZR-CAD HR4 E-VA (KE) and Shofu Block HC Hard AN (HA)]. The mechanical properties [Vickers hardness, flexural strength, and flexural modulus (storage in air at 23 ± 2℃ for 1 day, immersion in deionized water at 37 ± 2 ℃ for 7 days, or thermal cycling for 10,000 cycles)], inorganic filler content, surface roughness after toothbrush abrasion test (up to 12,000 strokes), water sorption (up to 28 days) and color difference (distilled water, coffee liquid, or curry liquid) were investigated for each resin composite block. The Vickers hardness of the blocks was in the order of AN<CL<KE<HA, which showed a trend same as that of the inorganic filler content. The flexural strength and flexural modulus after immersion in deionized water for 7 days or thermal cycling test for all blocks significantly decreased as compared with those in air. The toothbrush abrasion test showed that the surface roughness of each resin block increased as the number of abrasions increased. After 6-hour immersion, HA significantly increased the water sorption value as compared to the other blocks. The color difference after immersion in curry liquid for all blocks exceeded the value of 2.0 which is believed to distinguish the color difference by naked eyes. Under the present experimental conditions, mechanical properties, water sorption, abrasion by toothbrushing, color change behavior by food and beverage and inorganic filler contents of the resin blocks were varied among the resin composite blocks for CAD/CAM crowns of anterior teeth.
