Q. Classify biomaterials and list some examples?

Biologic classification is based on tissue response and systemic toxicity effects of the implant and is divided into three classes of biomaterials:
Biotolerant, bioinert, and bioactive

Biotolerant: such as PMMA are characterized by a thin fibrous tissue interface. The fibrous tissue layer develops as a result of the chemical products from leaching processes, leading to irritation of the surrounding tissues. Bioinert materials such as titanium, titanium alloys and alumina (Al₂O₃) are nearly chemically inert in the body and exhibit minimal chemical interaction with adjacent tissue. Tissue attachment with inert materials is through tissue growth into surface irregularities, by bone cement, or by press fitting into a defect.

Bioactive materials: Certain glasses, ceramics, and glass-ceramics that contain oxides of silicon, sodium, calcium, and phosphorus (SiO₂, Na₂O, CaO, and P₂O₅ ) form a chemical bond with bone, resulting in a strong mechanical implant/ bone bond. These materials are bond to bone (and in some cases to soft tissue) through a time-dependent, kinetic modification of the surface triggered by their implantation within living bone.