Objectives: This study evaluated the cutting efficiency of dental burs with different surface coatings on various reconstruction materials and analyzed the microscopic changes after multiple uses. Methods: Thirty block specimens (N=35, n=7) were prepared from various materials: CAD/CAM PMMA, direct resin composite, lithium disilicate, CAD/CAM nano-hybrid composite, and zirconia (12x4x4 mm³). The specimens were randomly assigned to cut under water cooling with one of seven bur types: Bur 1 (FG 307 CB), Bur 2 (6881.314.016), Bur 3 (FG 307 C), Bur 4 (ZR6881.314.016), Bur 5 (Prototype), Bur 6 (Prototype), and Bur 7 (Prototype). Each bur was used 10 times with a cutting depth of 3 mm. Images were taken of unused, used, and ultrasonically cleaned burs prior to data analysis (α=0.05). Results: Cutting efficiency varied significantly by material and bur type (p⟨0.05). Bur 3 and Bur 5 were most effective for PMMA, while Burs 5, 6, and 7 excelled with direct resin composite. Bur 7 was best for CAD/CAM composite, Bur 3 for lithium disilicate, and Bur 6 for zirconia. Burs 1 and 2 consistently performed poorly. Significance: Bur selection is important for efficient cutting, reducing chair time, material wear, and costs while improving restoration precision and bur longevity.
Erlinger et al. (Wed,) studied this question.