BACKGROUND: After tooth extraction, residual ridge resorption is a complicate process, while stress is one of the main causes. Recent studies have demonstrated that osteopontin (OPN) is a kind of agent that is sensitive to mechanical stress.OBJECTIVE: To study the role of OPN in mediating mechanical stress effect on bone, and to investigate the relationship of OPN and bone rebuilding, action mechanism of OPN and cell surface receptor and the relationship of OPN and osteoblast and osteoclast, in order to reveal the molecule mechanism of residual ridge resorption mainly caused by stress, and also to be a basic theory for clinical molecule therapy or gene therapy.RETRIEVE STRATEGY: PubMed was searched from January 1985 to June 2007 for English literatures with the searching words of "OPN, mechanical stress and bone resorption" and China Journal Full-text Database was also searched from January 1995 to June 2007 for Chinese literatures with the searching words of "OFN, mechanical stress and bone resorption". Fifty-two literatures were retrieved. The data were primarily selected. Inclusive criteria: being relative to role of OPN in mediating mechanical stress effect on bone. Exclusive criteria: repetitive studies.LITERATURE EVALUATION: Among the 52 literatures, including 6 Chinese and 46 English, 5 were rejected for objective independent from this study, 13 for repetitive contents, and so 34 literatures were involved for further analysis on the role of OPN in mediating mechanical stress effect on bone, 6 being review and the others being clinical or basic studies.DATA SYNTHESIS: ①After tooth extraction, residual ridge resorption is a complicate process. It also influences the effect of artificial denture, while stress is the main cause. ② OPN is widely distributed throughout the body, and has many physiologic functions. Recent studies have demonstrated that OPN is a kind of agent that is sensitive to mechanical stress. ③Bone is a special kind of biological tissue, bone resorption and bone rebuilding both can take place when it is lack of mechanical stress (atrophy of disuse),or endures mechanical stress. ④Bone rebuilding can be seen as the results of these molecule events. OPN, as a main protein, participates in the bone resorption and bone rebuilding. ⑤These OPN can be seen as a chemotatic factor to guide prosoma osteoclast to migrate to the surface of the bone, and mediate it to combine with the integrin on the surface of osteoclast so to promote the resorption of bone. So, OPN is a necessary factor in mechanical stress induced bone loss. ⑥OPN is a signal of transmission between osteoblast and osteoclast. ⑦OPN can be seen as a long acting feedback inhibition signal to inhibit bone mineralization.CONCLUSION: OPN is a kind of agent that is sensitive to mechanical stress. It plays an important role in mediating mechanical stress effect on bone.

BACKGROUND: Most of anti-osteoporosis drugs can only inhibit bone resorption, but can not improve the bone formation. So far, Strontium ranelate is the only anti-osteoporosis drug that has a dual effect on bone resorption and bone formation. Through the retrieval of related studies, the present review article evaluates the current understanding of strontium ranelate effects on bone resorption based on the pharmacologic experiments, clinical studies, action mechanisms. Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been widely used on clinic; however, there are still few reports addressing rhBMP-2-induced osteogenesis in intervertebral disc.