Bone cutting performance and mechanical properties of piezo-surgical tips: a nano-indentation study

Purpose: The aims of this study were to compare the mechanical properties of piezo-surgical tips such as nano -hardness, elastic modulus, surface roughness, and wear level, and to measure their cutting performance. Materials and Methods: In this study, 31 piezo-surgical tips were used, three for control and 28 for testing. The testing tips were equally divided into four groups with different numbers of osteotomies: the four-, 8-, 16-, and 32-osteotomy groups. The mean osteotomy duration was recorded during osteotomy. Scanning electron microscopy images of the tips in the test groups were obtained before and after osteotomy, and the wear level of the tips was measured. Results: A statistically significant increase was observed in the nano-hardness of the piezo-surgical tips depending on the number of osteotomy (for 4-use; 22.47 +/- 1.67H and for 32-use; 28.49 +/- 3.42H). The elasticity value of the testing tips was in the range of 218.55 +/- 15.74E to 241.26 +/- 10.46E, and all of the values were significantly higher than those in the control group (174.39 +/- 13.53E). As the frequency of use increased, a significant increase in surface roughness was observed (from 16.67 +/- 1.50 to 56.12 +/- 2.60). A positive correlation was found between the frequency of use and the wear level of the tips, and between the surface roughness and wear level of the tips. Conclusion: With the increase in the number of osteotomies, significant changes in the mechanical and physical properties of the piezo-surgical tips that affected their bone-cutting performance were observed.