Ten percent carbamide peroxide is an effective, safe home bleaching agent. Higher concentrations
are more effective, but there are mixed reports on their hardness and surface roughness effects on resin composites. To evaluate the effect of home bleaching agents; Opalescence Now 10% carbamide peroxide (Ultradent Products, USA) and Perfect Bleach 17% carbamide peroxide (Voco,
Germany) on the surface hardness of microhybrid resin composites; Filtek Z250 (3M ESPE, USA) and Point 4 (Kerr, USA) and their surface roughness of selected treatment. Thirty specimens were prepared using acrylic moulds (4mm diameter x2mm thick). N=5 controls placed in distilled water for 14 days.N=5 treated with Opalescence, and n=5 treated with Perfect Bleach for 2 hours every day for 14 days. Surface hardness was tested using Vickers hardness tester FV-7 (Future Tech Corp, Japan). Data analyzed with Mann-Whitney test with (P
Surface polishing affect the staining of nano-tooth coloured materials. Here we studied the effect of tea and coffee staining
on polished nano-composite resin and nano-ormocers. Eighty-four discs (5 × 2 mm) of Filtek Z350 and Ceram X were
fabricated using acrylic molds and polished with either: (1) Sof-lex (2) Enhance/Pogo (3) control (no polishing-Mylar).
After polishing, the tests materials were immersed in either tea or coffee (n=7), for 48, 96 and 168 h at 37°C. The colour
difference (ΔE) values were assessed with a spectrophotometer (Cecil CE 2021 UV/VIS), the data were analysed using
Kruskal-Wallis Test. The results showed that polishing significantly affected the ΔE values of both materials (p<0.05).
In all groups, Ceram X showed less staining than Filtek Z350. Both Filtek Z350 and Ceram X also reacted differently
in coffee and tea. Significant ΔE values for Filtek Z350 obtained with different polishing techniques exposed to coffee in
ascending order: Sof-lex < Enhance/Pogo < Mylar strip. For Ceram X, significant ΔE values obtained in exposure to
tea in ascending order: Pogo < Mylar < Sof-lex. Mylar caused more staining in Filtek Z350 whilst Sof-Lex caused the
least staining. However, in Ceram X, Enhance/Pogo caused the least staining. In conclusion, Ceram X is more colour
stable than Filtek Z350. It may be suggested to always use the polishing system produced by the same company that
produces the restorative material for better staining resistant.
Home bleaching agents may not be safe for composite resins. The purpose of this study was to evaluate the effects of 10 and 20% Opalescence(®) PF home bleaching agents on the surface roughness and hardness of universal nanocomposite (Filtek Z350), anterior nanocomposite (KeLFiL), and nanohybrid composite (TPH 3).