Evaluation of cutting edge integrity, surface degradation, and material loss in four implant drilling systems: an in vitro investigation in bovine rib bone

BACKGROUND: Implant drills are essential for precise osteotomy preparation, and their repeated use can affect surface integrity, sharpness, and material loss. This original study presents a comprehensive evaluation of four implant drill systems—conventional stainless steel drills (CS), hard-coated stainless steel drills (HCS), ceramic drills (CD), and tapered expansion drills (TE)—by assessing cutting edge wear, surface roughness, and material loss at defined usage intervals. METHODS: A total of 160 osteotomies were performed on fresh bovine rib bone blocks using four different drill systems. Each group included 40 repetitions. Each drill was analyzed at baseline and after 10, 20, 30, and 40 osteotomies. Drilling was performed under standardized parameters (23 °C, 800 rpm, 2 kg axial load, 50 mL/min irrigation). Surface roughness was measured using a stylus-based contact profilometer. SEM was used for morphological inspection, and a precision analytical balance (± 0.0001 g) was used to detect material loss. RESULTS: No significant material loss was observed in any group during the first 20 osteotomies. The ceramic drills demonstrated zero material loss and minimal surface wear across all time points. HCS drills showed the highest variability in mass loss (up to 136.5 µg), and TE drills exhibited visible edge degradation after 30 uses. SEM revealed progressive morphological changes, including edge rounding and microcracks, predominantly in HCS and TE groups. While differences between groups were not statistically significant, ceramic drills consistently demonstrated superior structural preservation. CONCLUSION: Repeated use of implant drills results in gradual wear, particularly in metallic systems. Ceramic drills exhibited the most stable performance, suggesting their potential advantage for extended clinical use.