Evaluation of color stability, wear, and fracture resistance of preformed Bioflx and zirconia crowns: An in vitro study.

BACKGROUND: The ideal crowns for primary teeth should be esthetic, durable, and easy to place. Preformed zirconia crowns, although the most commonly used, esthetically pleasing, require significant tooth reduction, lack flexibility and adjustability, and cause wear of opposing teeth. Recently, new high-strength, medical-grade resin polymer preformed crowns have been introduced, promising to address these limitations. AIM: This in vitro study aimed to evaluate and compare the color stability, wear, and fracture resistance of newly introduced resin polymer crowns (Bioflx) with preformed zirconia crowns. MATERIALS AND METHODS: Forty-eight extracted human primary molars were prepared, followed by the placement of Bioflx and zirconia crowns as per the respective study groups (n = 12). The samples were subjected to thermocycling and chewing simulations to mimic aging. Pre- and postaging color stability, wear, and fracture resistance values were assessed. The mean values were calculated and the data were subjected to the statistical analysis. RESULTS: Bioflx crowns exhibited significantly higher color stability compared to zirconia crowns after aging (P < 0.001). Bioflx crowns exhibited less volumetric wear of crown material and antagonist teeth compared to zirconia crowns (P < 0.05). Regarding fracture resistance, Bioflx crowns maintained their strength after aging (P > 0.05), whereas zirconia crowns experienced a highly significant decline in strength after aging (P </= 0.001). CONCLUSION: Bioflx crowns offer a promising alternative in restorative pediatric dentistry. They demonstrate superior color stability and wear resistance and maintain adequate fracture strength following aging. Further clinical studies are warranted to validate these results and explore their broader applicability.