Bone tissue microstructure and function. Part I: Adaptation mechanisms [Microstruttura e funzione del tessuto osseo. Parte I: Meccanismi di adattamento]

Objectives: The aim of this study is to carry out a review of the bone micro-structure adaptive mechanisms and function in relation to dental applications. Materials and methods: The relationship between bone micro-anatomical aspects and history of theoretical bone physiology has been evaluated in detail. Results: The modern theory of the physiology of bone is consistent with the integration among regional acceleratory phenomenon, Utah paradigm, and mechanostat hypothesis. Bone modeling and remodeling can respond to pleiotropic stimuli, including quantum concept of cell activation and dynamic loading. Finally, in the case of implants inserted in augmented bone with xenograft not completely resorbable biomaterials, a reduced mechanical competence of the peri-implant bone should be taken into account. Conclusions: The static load, within the limits of proportionality, does not affect bone resorption. To facilitate the "local acceleratory phenomenon" after implant bed preparation and during implant placement the blood clot should be preserved by any irrigation procedure. Progressive loading procedures should be used for implants placed in augmented bone with xenograft biomaterials with incomplete resorption behavior