Physiology of osseous and fibrous integration

The adaptation of bone to dental implants by rigid osseous integration is believed by many to be the hallmark of clinical success. However, many implants that are slightly mobile with a fibrous interface also function well in clinical application. Physiologically, why does bone respond by rigidly integrating one implant and producing a fibrous interface with another? The healing mechanism for rigid osseous integration is well known and accepted. Conversely, the development of a fibrous interface is incompletely understood. This article suggests a unified concept of the interrelationship between fibrous and osseous integration.