A biomaterial is any engineered substance that is placed in human body for therapeutic (treatment/ augmentation/ repair/replacement/restoration) or diagnostic purposes. The science of biomaterials is about more than 200 years old. The experiments for biomaterials used in dental science, first began in 1900s by G.V. Black at Northwestern University. He did experiments on dental amalgam.
Properties of Biomaterials
- Modulus of elasticity of implant should be comparable to bone (18 GPa)
- Implant material should have high Tensile and compressive strength.
- Dental materials should have high Yield strength and fatigue strength
- Implant materials should have at least 8% Ductility
- The surface tension, surface energy, surface roughness of the materials should be evaluated. Wennerberg and coworkers have classified implant surfaces according to surface roughness: Minimally rough (0.5-1 m), intermediately rough (1-2 m) and Rough (2-3 m); the implant surfaces can also be divided according to their texture: concave texture and convex. The implant surface can also be classified according to type of surface irregularities like isotropic surfaces which has similar topography regardless of measuring direction and Isotropic surfaces which have a clear direction and considerable variety in roughness.
- Biocompatibility of the materials should also be assessed in terms of corrosion resistance. Crevice corrosion (at narrow regions like screw-implant interface), pitting corrosion (occurs in implants with small surface pits), galvanic corrosion (due to difference in electrical ingredients), electrochemical corrosion (oxidation and reduction of metals due to transfer of electrons) etc. Corrosion causes roughening of surfaces, weakening of restoration, and release of elements from metal/ alloy, harmful reactions. Also, the nearby tissues may get discolored and allergic reactions may result from release of elements.
Dental Implant Materials
- Metals which are Bio tolerant - Tantalum, Aurum chromium-cobalt alloys, Stainless steel , Niobium
- Polymers which are Bio tolerant - Polymethylmethacrylate, Polyethylene Polyamide Polytetrafluroethylene Polyurethane
- Metals which are Bio inert - pure titanium alloy (Ti-6AL-4U)
- Ceramics which are Bio inert - Zirconium oxide , Aluminum oxide
- Ceramics which are Bioactive - Carbon-silicon
Disclaimer: The information given in this write-up is purely for educating the reader. It is not meant to be a substitute for any advice from a medical expert.