Natural antioxidants to restore immediate bond strength to bleached enamel: Systematic review and meta‐analysis of in vitro studies

Abstract

Objective To evaluate whether natural antioxidant treatment would enhance the immediate bond strength of dental adhesives to bleached enamel through a systematic review and meta‐analysis. Materials and methods Two reviewers performed a literature search up to November 2019 in seven databases. Only in vitro studies that evaluated the effect of the application of natural antioxidants in the bond strength of dental adhesives to bleached enamel were included. Analyses were carried out using RevMan 5.3.5 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). A global analysis was performed with random‐effects models at a significance level of p < 0.05. Results Twenty‐four studies were included in the meta‐analysis. Both in‐office (p ˂ 0.001) and at‐home (p ˂ 0.001) bleaching reduced the immediate bond strength. When compared to bleached enamel, all antioxidants improved the bond strength, but only grape seed extract/proanthocyanidin and lycopene restored it to the control values (p ˃ 0.05). Conclusion In vitro available evidence suggests that the use of natural antioxidants can be beneficial when performing immediate resin‐based restorations after bleaching, however, these results should be taken with caution since they are based on medium and high risk of bias studies; low bias studies are needed to draw relevant conclusions. Clinical significance Despite the lack of clinical evidence, the present study confirms the benefits of applying natural antioxidant agents to enhance the in vitro bond strength when performing immediate esthetic restorations after bleaching. Since certain antioxidant agents proved more effective than others, clinical investigations may be focused on the ones that withhold the most promising results. The application of natural antioxidants after bleaching may enable immediate esthetic restorations to be performed.

Does the application of whitening dentifrices during at-home bleaching affect the bond strength of resin composite to dentin?

“…The present findings are in agreement with some studies that reported no harmful effect on the bond strength of restorations bonded to teeth after at-home bleaching [ 30 – 33 , 39 , 40 ]. In contrast, several studies indicated lower adhesion strength in teeth recently exposed to professional bleaching procedures [ 18 , 23 , 41 – 43 ]. The investigations on the use of whitening dentifrices on bond strength also reported controversial results, with some studies reporting detrimental effects [ 7 , 11 , 14 ], whereas others showed comparable [ 9 , 44 ] or even higher [ 45 ] bonding values as compared to regular dentifrices.…”

“…Several strategies have been suggested to neutralize and reverse the effects of bleaching agents on bond strength such as delaying the restorative procedures up to 2 weeks after whitening [17][18][19] or treatment of the tooth surface with chemicals such as sodium ascorbate (a potent antioxidant), catalase, ethanol or water to dissociate residual peroxides and oxygen free radicals from the substrate [13,[20][21][22][23]. Another option to enhance the bond strength may be the increase in the polymerization time of adhesive systems.…”

Comparative evaluation of the postbleaching application of sodium ascorbate, alpha‐tocopherol, and quercetin on shear bond strength of composite resin to enamel

“…Using antioxidants appears to be the best, fastest, and most convenient way of reversing the decreased bond after bleaching (Leandrin et al, 2020;Olmedo et al, 2021;Pooja et al, 2021;Rodríguez-Barragué et al, 2021;Shamsedin et al, 2017;Y. X. Xu et al, 2021).…”

“…Using antioxidants appears to be the best, fastest, and most convenient way of reversing the decreased bond after bleaching (Leandrin et al, 2020 ; Olmedo et al, 2021 ; Pooja et al, 2021 ; Rodríguez‐Barragué et al, 2021 ; Shamsedin et al, 2017 ; Y. X. Xu et al, 2021 ). The results of the present study demonstrated that none of the antioxidant solutions reestablish the compromised bond strength in the bleached enamel.…”

Effect of heating antioxidants and delayed bonding on bond strength to bleached enamel

“…The antioxidant activity of GSE and PBE can be attributed to the multiple donor sites found on its OPC which have a specificity for trapping the superoxide and hydroxyl free radicals which enhances free radical scavenging and increases the bond strength of composite to bleached enamel [18].…”