Effects of home bleaching on surface hardness and surface roughness of an experimental nanocomposite

Abstract

Objective: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).Materials and Methods:Fifty-four composite resin samples with 18 samples for each type of composite resin were prepared using acrylic molds (4 × 2 mm). Each type of composite resin was further divided into three groups [n = 6 controls were placed in distilled water for 14 days and the other two groups of n = 6 were bleached with 10 and 20% carbamide peroxide (CP), respectively for 14 days]. Surface hardness of the composite resin was tested with a Vickers hardness tester, whereas surface roughness was tested with atomic force microscopy (AFM).Results:There were significant changes in the surface hardness of KeLFiL and TPH 3. However, all the tested materials showed no significant changes in the surface roughness.Conclusion:After 14 days of home bleaching treatment, there was no adverse effect on the surface roughness of all three composite resins, although the surface hardness for KeLFiL and TPH 3 were significantly reduced.

What adverse effects does tooth-whitening have on dental restorations?

“…14,15,17,29,33,34 Findings of a decrease in microhardness are consistent with several additional studies. 13,14,35,36,37 Although a reduced microhardness was found, there was controversy regarding whether this is limited to the composite surface layers and can be removed with post-operative re-polishing 13,38 or if the damage extends deeper. One study observed softening of sub-surface layers and concluded that it is unlikely that post-operative polishing is sufficient to reverse the damage.…”

Comparison of Different Bleaching Treatments Effect on Micro Hardness of Four Different Aged Composites

“…It has been reported that about 40% of people have at least one repair in their mouth (7). Also, composites, as tooth isochromatic materials, have been welcomed by the public and are used widely in dental restoration (5). Thus, it is necessary to investigate the treatment effect of bleaching on composite properties in order to select the best treatment for the patients.…”

“…Hardness is defined as resistance of a material against depression or penetration of other materials (8). Results of various studies about composites microhardness after bleaching have reported a decrease in hardiness (2,3,5,7,9,(12)(13)(14)(15)(16), increase in hardiness (14,(17)(18)(19) or no significant change (3,8,(20)(21)(22)(23)(24)(25)(26).…”

“…These substances are oxidizers and produce free radicals during decomposition (5). Stain removal is done often by shortening these colored molecules via oxidation together with breaking the conjugated bonds by OH and OOH radicals, so that molecules with lower molecular weight reflect less light (6).…”

Effect of 15% Carbamide Peroxide on the Surface Roughness and Adhesion of Streptococcus mutans to Microhybrid Composite Resin and Giomer

“…10,11 In patients with poor oral hygiene and a cariogenic diet, giomer might be a good choice for decreasing the effects of a poor oral environment due to its capacity to release fluoride and high polishability. 20,21 In addition, some studies have shown that SR of restorative materials increases after bleaching with carbamide peroxide. [22][23][24][25][26] Mohammadi et al, 27 too, showed a statistically significant difference in the SR of giomer before and after bleaching with carbamide peroxide.…”