Bioceramics

Bioceramics are a class of ceramic materials designed for medical and dental applications that interact with biological tissues. They include bioinert ceramics such as alumina and zirconia, and bioactive or bioresorbable ceramics such as calcium phosphates (for example hydroxyapatite and beta-tricalcium phosphate) and bioactive glasses. Their primary role is to replace, repair, or interface with bone and teeth while maintaining chemical stability and mechanical compatibility with the host.

Bioceramics are chosen for properties such as biocompatibility, chemical stability, and, in some cases, the ability to bond with bone. Bioinert ceramics resist tissue reactions and wear well, making them suitable for joint bearings. Bioactive calcium phosphates are osteoconductive, meaning they support bone growth on their surfaces, and can gradually dissolve and be replaced by new bone. Bioactive glasses can bond to bone and soft tissue and can be tailored to degrade over time. Porosity, surface chemistry, and microstructure influence cellular response.

Common materials include hydroxyapatite, tricalcium phosphate, and biphasic calcium phosphates; calcium phosphate cements and scaffolds are used for bone defect filling. Alumina and zirconia offer high hardness and wear resistance for load-bearing applications and dental implants. Bioceramics are often used as coatings on metallic implants to improve bonding and reduce wear, and as bone graft substitutes.

Limitations include inherent brittleness and fracture risk, particularly for load-bearing components, and mismatches in degradation rates for resorbable formulations. Ongoing research aims to improve toughness, control resorption, and create composites with polymers or metals to extend clinical performance.