Comparative Evaluation of Compressive Strength, Microhardness, and Wear Resistance in Preformed Resin Polymer,...

Purpose: To evaluate the physical and mechanical properties of 3 types of preformed crowns used in pediatric dentistry. Methods: Thirty crowns each were used for 3 study groups: Group 1-BioFlx^® Crowns (BFCs); Group 2-stainless steel crowns (SSCs); and Group 3-preformed zirconia crowns (PZCs). The crowns (mandibular right second molar, size 4) were cemented on identical 3D printed teeth models. These were then mounted in acrylic blocks for the assessment of wear, compressive strength, and microhardness. Results: A significant difference (P ≤ 0.05) was observed in the compressive strength of the crowns evaluated. The highest compressive strength was seen in SSCs, followed by BFCs, and the lowest with PZCs. The difference in the microhardness of the 3 crowns was significant (P ≤ 0.001), with the highest demonstrated by PZCs, followed by SSCs, and the lowest with BFCs. The wear rate was found to be highest with SSCs, followed by PZCs, and lowest with BFCs. Conclusion: Stainless steel crowns and preformed zirconia crowns demonstrate high compressive strength and microhardness respectively, while BioFlx® Crowns showed the highest wear resistance of the 3 crowns tested.