Effects of over-the-counter at-home whitening products with LED light on surface roughness of partially- and fully crystalized CAD/CAM lithium disilicate ceramics.

The aim of this study is to evaluate the effect of over-the-counter (OTC) at-home whitening products with LED light on partially- and fully-crystalized CAD/CAM lithium disilicate ceramics. Two partially-crystalized CAD/CAM lithium disilicate ceramics, Amber Mill and IPS e.max CAD, and one fully-crystalized CAD/CAM lithium disilicate ceramic, n!ce Straumann, were used. The specimens were divided based on treatment with OTC whitening products: no treatment provided, Colgate Optic, Crest 3D and Walgreens Deluxe. The surface roughness of the specimens was evaluated with an optical profilometer and scanning electron microscopy. The three LED whitening products significantly increased the surface roughness and changed surface morphology of Amber Mill and IPS e.max CAD but no differences for n!ce Straumann. OTC at-home whitening products with LED light can significantly increase the surface roughness of restorations fabricated with these partially-crystalized CAD/CAM lithium disilicate ceramic restorations. However, these products do not increase the surface roughness of restorations fabricated with this fully-crystalized lithium disilicate ceramic.

Light Transmission for a Novel Chairside CAD/CAM Lithium Disilicate Ceramic.

AIM: To evaluate light transmission in a novel chairside CAD/CAM lithium disilicate ceramic with different thicknesses and with and without polishing. MATERIALS AND METHODS: Sixty flat samples (10 specimens/group) were fabricated from novel chairside CAD/CAM lithium disilicate ceramic blocks (Amber Mill, Hass Bio) with different thicknesses and with and without polishing as follows: (1) 1.0 mm thickness without polishing (1.0NoP); (2) 1.0 mm thickness with polishing (1.0Po); (3) 1.5 mm thickness without polishing (1.5NoP); (4) 1.5 mm thickness with polishing (1.5Po); (5) 2.0 mm thickness without polishing (2.0NoP); and (6) 2.0 mm thickness with polishing (2.0Po). Specimens were polished with a polishing system for lithium disilicate restorations following the manufacturer's recommendations. Light transmission was evaluated with a curing radiometer. Obtained data were subjected to two-way ANOVA followed by Tukey's post hoc tests (α = 0.05). SEM observations were conducted to evaluate surface microstructure. RESULTS: The light intensity through the lithium disilicate blocks with and without polishing was 200.9 mW/cm2 (16.1%) and 194.4 mW/cm2 (15.6%) for 1.0 mm specimens, 119.3 mW/cm2 (9.5%) and 111.9 mW/cm2 (9.0%) for 1.5 mm specimens, and 102.3 mW/cm2 (8.2%) and 96.0 mW/cm2 (7.7%) for 2.0 mm specimens. SEM images showed a smoother surface with polishing compared to nonpolished specimens. CONCLUSION: The thickness and polishing of the restorations were both significant influential factors in light transmission. CLINICAL SIGNIFICANCE: The range of light transmission percentage through the novel chairside CAD/CAM lithium disilicate blocks was 7.7-16.1%, suggesting that light attenuation through the material may influence the polymerization reaction of resin luting cement in the bonding process.