We study structure-mechanical property relationships of calcified tissues (bone, cementum, dentin, enamel). The main functions of these biological materials are mechanical, but much work is needed to understand how their unique and versatile properties are derived based on combinations of protein and mineral. We seek insight into biomineralization processes associated with these tissues during development, resulting from disease, or repair and regeneration from clinical treatments. We also focus on natural interfaces between various calcified tissues and artificial interfaces between the tissues and artificial, e.g., dental restorations, implants, bioactive substrates. We use a wide variety of approaches including atomic force microscopy (AFM); and AFM-based nano-indentation) as well as other complimentary methods including wet SEM and x-ray microanalysis, and participate in wide ranging collaborations in the Bay Area. This work helps define alteration in properties and structure with hydration state, mineral level, and variations induced by disease and physiological processes. This information is needed to develop a composite structural model of calcified tissues and can assist in the development of bio-inspired materials and tissue engineering.