Clinical comparison of different glass ionomer-based restoratives and a bulk-fill resin composite in Class I cavities: A 48-month randomized split-mouth controlled trial

Objective: The aim of this study is to compare the retention rates (primary outcome) of high-viscosity glass ionomer (GI), glass carbomer (GC), zirconia-reinforced GI (ZIR), and bulk-fill (BF) composite resin restorations. Secondary outcomes included anatomical form, marginal adaptation, marginal discoloration, color match, surface texture, post-operative sensitivity and secondary caries. Methods: Two calibrated operators placed 128 restorations in 30 patients with a mean age of 21 years. The restorations were evaluated by one examiner at baseline and at 6, 12, 18, 24, and 48 months using the modified US Public Health Service criteria. The data were statistically analyzed using Friedman test. Differences between restorations were analyzed using Kruskal–Wallis test. Results: After 48 months, 23 patients and 97 restorations (23 GI, 25 GC, 24 ZIR, and 25 BF) were evaluated. Patient recall rate was 77%. No significant difference was observed between the retention rates of the restorations (p > 0.05). GC showed significantly lower results than the other three fillings in terms of anatomical form (p < 0.05). There was no significant difference in the anatomical form and retention between GI, ZIR, and BF (p > 0.05). No significant change was observed in the postoperative sensitivity or secondary caries for any of the restorations (p > 0.05). Conclusions: GC restorations showed statistically lower anatomical form values, indicating lower wear resistance than the other materials. However, no significant difference was observed in the retention rates (as primary outcome) as well as the other secondary outcomes of the four different restorative materials after 48 months. Clinical Significance: GI-based restorative materials and BF composite resin restorations in Class I cavities yielded satisfactory clinical performance after 48 months.