A study on the effect of AlTiN and TiCN coatings on the tribological properties of dental drills

Bone drilling is a common and necessary procedure in orthopedics and dentistry. If the temperature rises above a certain threshold during bone drilling, it can lead to irreversible death of bone cells, which is called bone necrosis. If heat generation causes thermal necrosis, the stability of the implant is compromised and implant failure occurs. Titanium carbonitride (TiCN) and aluminum titanium nitride (AlTiN) coatings were deposited on a 440 M stainless steel substrate by cathodic arc physical vapor deposition to achieve the best solution to avoid thermal necrosis. The chemical composition, microstructure, mechanical properties, and wear resistance of the TiCN coatings were investigated by X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray analysis, scratch test, Rockwell-C adhesion, nanoindentation, and tribometer tests. The electrochemical behavior of the sample in artificial saliva solution was predicted by the dynamic potential polarization method, that is, corrosion potential (Ecorr) and corrosion current density (Icorr). Bone drilling was performed on hydroxyapatite blocks at a constant speed of 520 rpm without irrigation, using thermocouple and thermographic measurement methods. The autoclave method was preferred to determine the sterilization resistance of the coating at two different cycle times. The results obtained show that the TiCN coating has a significantly lower coefficient of friction and has the highest wear resistance in addition to a low bone temperature, making this coating a good candidate for dental drills.