SEM Evaluation of Surface Wear on Drills from Selected Implant Systems-In Vitro Study

The aim of this in vitro study was to evaluate the degree of surface wear in implant drills from four commercial systems subjected to standardized osteotomy cycles.

Four implant systems (Osstem, Megagen, Straumann, and Bego) were evaluated using sets of three drills of increasing diameters. A total of 120 osteotomies were performed in standardized porcine rib specimens under controlled drilling conditions (1200 rpm, continuous 4 °C saline irrigation, 32:1 reduction handpiece). After each drilling series, drills were cleaned, sterilized, and analyzed using SEM in three orientations. Wear was assessed using a seven-parameter scoring system. Multifactorial ANOVA, Pearson correlation, and hierarchical clustering were employed to evaluate the effects of drill brand, diameter, and wear patterns.

Both drill brand and diameter significantly influenced total wear scores (p < 0.001). Small-diameter pilot drills exhibited the highest wear, while large-diameter drills showed minimal degradation. Among the systems tested, Bego drills demonstrated the greatest overall wear, whereas Osstem drills-particularly the 2.0 mm drill-displayed unusually low wear for their size. A strong negative correlation between drill diameter and wear score was observed. Cluster analysis identified distinct wear patterns associated with specific drill sizes, with small drills showing prominent guide-face nicks and accumulation formation, medium drills exhibiting chipping and rake angle cleavage, and large drills presenting minimal wear. SEM imaging confirmed progressive surface deterioration, including edge rounding, microchipping, and irregular surface defects.

Implant drill wear is strongly dependent on drill diameter, and cutting geometry. Small-diameter drills are most susceptible to surface degradation, which may increase friction and thermal load during osteotomy. Systems with enhanced material properties or optimized geometries demonstrated superior wear resistance. These findings highlight the importance of monitoring drill condition, adhering to recommended reuse limits, and considering advanced drill coatings or materials to ensure safe and predictable implant site preparation. Further research incorporating real-time thermal measurements and extended drilling cycles is needed to establish evidence-based guidelines for drill longevity and clinical performance.