Evaluation of the repair capacities and color stabilities of a resin nanoceramic and hybrid CAD/CAM blocks

Abstract

PURPOSE. This study evaluated the color stabilities of two computer-aided design and computer-aided manufacturing (CAD/CAM) blocks and a nanofill composite resin and the microtensile bond strength (mu TBS) between the materials. MATERIALS AND METHODS. Twelve specimens of 4 mm height were prepared for both Lava Ultimate (L) and Vita Enamic (E) CAD/CAM blocks. Half of the specimens were thermocycled (10,000 cycle, 5 degrees to 55 degrees C) for each material. Both thermocycled and non-thermocycled specimens were surface treated with one of the three different methods (Er,Cr:YSGG laser, bur, or control). For each surface treatment group, one of the thermocycled and one of non-thermocycled specimens were restored using silane (Ceramic Primer II), universal adhesive (Single Bond Universal), and nanofill composite resin of 4 mm height (Filtek Ultimate). The other specimens were restored with the same procedure without using silane. For each group, 1 x 1 x 8 mm bar specimens were prepared using a microcutting device. Bar specimens were thermocycled (10,000cycle, 5 degrees to 55 degrees C) and microtensile tests were performed. Staining of the materials in coffee solution was also compared using a spectrophotometer. Data were analyzed using one-way ANOVA, t-test and post-hoc Scheffe tests. RESULTS. mu TBS were found similar between the thermocycled and non-thermocycled groups (P>.05). The highest mu TBS (20.818 MPa) was found in the non-thermocycled, bur-ground, silane-applied E group. Silane increased mu TBS at some E groups (P<.05). Composite resin specimens showed more staining than CAD/CAM blocks (P<.05). CONCLUSION. CAD/CAM blocks can be repaired with composite resins after proper surface treattilents. Using silane is recommended in repair process. Color differences may be shown between CAD/CAM blocks and the nanofill composite after a certain time period.