Vol. 11, Issue 3, Part C (2025)

Statement of Problem: The use of CAD/CAM in dentistry has become more widespread. Despite this, limited attention has been paid to the challenges clinicians face when cutting different CAD/CAM restorations intraorally. Additionally, there is insufficient evidence regarding the optimal grit size and type of rotary instrument for their effective cutting. Aim: To compare the Cutting Efficiency of Different Grit Sizes Burs on different CAD/CAM Materials Introduction: The cutting efficiency of dental burs plays a crucial role in the preparation of CAD/CAM materials like zirconia and polymethyl methacrylate (PMMA). The aim of this study is to evaluate the cutting efficiency of different grit sizes of diamond burs on zirconia and PMMA cuboid chips, assessing their performance in terms of surface roughness & cutting depth. Materials and Methodology: This in-vitro study used CAD/CAM fabricated cuboid chips of zirconia and PMMA. The cutting efficiency of three different grit sizes of diamond burs (fine, medium, and Standard) was evaluated. Cutting depth and surface roughness of the samples was evaluated and compared. The experiment was repeated for 7 zirconia and 7 PMMA chips for 3 different grit sizes burs and statistical analysis was done. Results: Extra-fine burs likely resulted in smoother surfaces for both Zirconia and PMMA samples Cutting depth was achieved more with Fine bur in Zirconia samples this can be because of increase in surface area while in PMMA samples, Standard burs exhibited more cutting depth Conclusion: Understanding the optimal bur grit size for different materials helps clinicians achieve better occlusal adjustments, enhance patient comfort, and extend restoration lifespan. For efficient cutting, fine burs are recommended for zirconia, while standard burs work well for PMMA. For occlusal adjustments, extra fine burs are ideal for both materials, ensuring less surface roughness. This study offers valuable guidance on selecting the right diamond rotary instrument for crown sectioning and occlusal adjustments in CAD/CAM zirconia and PMMA restorations, minimizing damage risk and reducing procedure time for better patient outcomes.