Effect of Postoperative Bleaching on Clinical Performance of Three Contemporary Composite Resins

Objectives: To evaluate the clinical performance of three contemporary nano-composite resins placed in class IV cavities in maxillary teeth after in-office bleaching over one-year follow-up period. Methods: 15-subjects (selected according to specific criteria) with class IV cavities were divided into three groups according to the restorative material: Beautiful-II (Shofu Dental Corporation, USA), Ceram-x-mono (DeTrey, Dentsply, Germany) and IPS-EmpressDirect (Ivoclar Vivadent, USA). Each group was randomly restored with the (A1) shade of the same restorative material type (n=12). Clinical evaluation was carried out before bleaching (baseline), two days after, 3-months, 6-months, and one-year post-bleaching. Color match, retention, anatomic form, surface roughness, recurrent caries, marginal discoloration, and marginal integrity were evaluated using modified Ryge criteria. (A) and (B) scores were considered clinically acceptable, while (C) and (D) scores were considered clinically unacceptable. The data were statistically analysed using ANOVA and Chi-square test (Х2). Results: The three groups showed statistically significant difference in color match between teeth and composite restorations after inoffice bleaching. Post-bleaching color match was maintained within the acceptable range except for ISP-Empress-Direct group, which was inferior in color match and marginal integrity at one-year evaluation period and needed replacement. The survival rate of the three materials was 100%. All other evaluated parameters (anatomic form, surface roughness and marginal integrity) were considered clinically acceptable in one-year evaluation period. Conclusion: Postoperative In-office bleaching had no detrimental effect on any of the composite resins used over one-year period. When bleaching is used in conjunction with direct restoration, postoperative bleaching can be successfully performed by matching the anticipated whitened tooth shade using medium opaque nanohybrid composites. Using high translucent enamel and opaque dentin shade might not be recommended when in-office bleaching is planned. When postoperative bleaching is planned, the choice of the restorative material may influence the clinical outcome and long term success. Clinical relevance: There are various ways to use bleaching in conjunction with direct restoration. Preoperative bleaching may prolong the treatment phase. Postoperative bleaching may save time and effort if we can select a suitable composite resin that is resistant to bleaching and can match the anticipated color after bleaching.