Machining Medium Effect on Biocompatibility of Titanium-Based Dental Implants

Titanium is the material of choice for dental implants with its outstanding density to strength ratio, fatigue resistance and exceptional surface properties. In the manufacturing of dental implants, titanium rods are shaped into implant screws in a machining medium to help cool the system and provide lubrication to control the implants surface roughness. It is common to use a machining oil as the coolant and lubricant, followed by sandblasting the implant surface with large grit and acid etching technique (SLA) to prepare the final product. The focus of this study is to compare the biocompatibility of the titanium dental implants shaped in machining oil versus deionized water (DIW) as a machining medium. It was observed that the machining in oil-based medium can lead to oil residue left on the implant surface even after the sandblasting acid-etching (SLA) treatment, leading to compromised biocompatibility. As a method of remedy, chemical mechanical nano-structuring (CMNS) technique is implemented and evaluated against the SLA treatment as an alternative. CMNS is a chemical and mechanical surface treatment method, and it helped enhance the biocompatibility of the implants by effective removal of oil residue while controlling the surface roughness as well as surface passivation in simulated body fluid (SBF). While the residual machining oil can demote fibroblast cell growth, and simultaneously promote bacteria growth on the titanium-based implants, the CMNS method was efficient in increasing cell viability and decreasing bacteria growth on both oil and deionized water (DIW) medium machined dental implants.