Surface modulation of silicon nitride ceramics for dental implant

Objectives: Titanium has long been used in dental implants and is providing a viable solution for replacing missing tooth since many years. Recently, silicon nitride (Si₃N₄) ceramics have attracted attention in the field of orthopedics because of their biocompatibility and high toughness. Si₃N₄ ceramics are presently used in spine implant. However, there is yet too little experimentation available on silicon nitride for dental applications. The present study focuses on Si₃N₄ as a dental bioceramic. Different grades of Si₃N₄ alloyed with oxides were studied and compared with respect to their wetting angles with pure water and surface morphology at the microscopic scale.
Methods: The surfaces of Si₃N₄ disks were observed by laser scanning microscopy, atomic force microscopy and scanning electron microscopy. Wetting angles were measured on Si₃N₄ disks and their quantitatively hydrophilicity evaluated.
Results: The wetting angle could be significantly reduced upon appropriate surface treatments. The average roughness also increased as compared to as-fired samples. A highly acicular surface was revealed upon treating the surface in acidic solution by using scanning electron and laser microscopies.
Conclusions: The observed improvement in wetting angle has important implications for dental treatments including an enhanced cellular affinity and, possibly, better osteointegration.This study shows the potential of Si₃N₄ as a candidate biomaterial in the field of dental medicine.