Self-regenerative capacity of intra-oral bone defects

To provide an overview on the self-regenerative capacity of various types of intra-oral bone defects.

This paper has narratively reviewed the most important aspects of bone biology and the healing outcomes related to the self-regenerative capacity (i.e. without the placement of any biomaterial) of bone defects that occur following tooth extraction, autogenous graft harvesting, periapical lesions, cystic lesions of the jaws, third molar extraction and experimentally created ridge defects.

In animals (i.e. dogs and monkeys), the greatest changes in horizontal and vertical dimension occur during the first 6 months following tooth extraction. In humans, bone remodelling may take from several months to years and exhibits marked inter-individual variability. Following tooth extraction at compromised sites (e.g. presence of severe bone loss at the time-point of extraction), the healing may occur slower and a substantial volume reduction can be expected than following tooth extraction at non-compromised sites. In the mandibular symphysis and ramus, the bone defects resulting following bone block harvesting are gradually healing to a large extent, but complete healing appears not to occur due to poorer space provision and wound stability capacities. Defects after peri-apical surgery display a substantial self-regenerative capacity and heal at a great extent without the use of any adjunct measures. The vast majority of jawbone defects after cystectomy heal at a great extent and without apparent influence in the shape of the jaw, without the need of adjunct measures. After surgical removal of mandibular third molars, bone fill can be observed over a period of at least 12 months, with the most substantial change (e.g. the greatest bone fill) occurring during the first 3 months after surgery. However, complete fill of these residual bone defects does not always occur.

Intra-oral bone defects possess a high self-regenerative capacity. Factors such as extent of bone loss, presence of bony walls, closed healing environment, space provision and mechanical wound stability substantially influence healing/regeneration.