Influence of Peroxide-Based Bleaching and Laser Activation on Dental Composite Integrity

Abstract

 Introduction: Tooth whitening in the presence of dental restorations requires special consideration, as restorative materials respond differently to bleaching agents compared to natural dental tissues. Active bleaching substances may alter the physical and mechanical properties of composites, potentially compromising the integrity and longevity of restorations.

 Aim: This study aimed to evaluate the impact of bleaching agents with different concentrations, as well as additional laser activation, on the properties of selected dental composites.

 Materials and Methods: Four composite materials were selected: G-aenial Universal Flo (GC) and ESTELITE UNIVERSAL FLOW (Tokuyama Dental) with three different viscosity levels. Whitening procedures were performed using Opalescence gels (Ultradent) containing active agents at concentrations of 10%, 16%, and 40%. In addition, a subset of specimens was exposed to laser irradiation. Tribological tests, microscopic surface analyses, and microhardness measurements were carried out to assess the influence of bleaching protocols.

 Results: The bleaching process resulted in adverse effects on the composites’ properties. A reduction in microhardness, alterations in surface morphology, and increased wear susceptibility were observed. The degree of degradation was influenced by both the concentration of the bleaching agent and the use of laser activation. The observed changes are likely associated with polymer matrix degradation caused by hydrogen peroxide and carbamide peroxide present in bleaching gels.

 Conclusion: Tooth whitening procedures, particularly those involving higher peroxide concentrations and laser activation, negatively affect the structural and mechanical properties of dental composites. These findings emphasize the need for clinicians to carefully consider restorative materials when planning whitening treatments in patients with composite fillings.