Alveolar socket preservation technique: Effect of biomaterial on bone regenerative pattern

Abstract

Background: There is a lack of evidence in the literature on the correlation between histomorphometric findings and gene/protein expression markers for bone metabolism.

Aim: Evaluation of the histological features, changes in protein expression and gene activation for specific markers of bone metabolism following application of the alveolar ridge preservation technique with magnesium-enriched hydroxyapatite (MgHA).

Materials and methods: For each patient (n=15), bone samples were harvested after tooth extraction and processed for immunohistochemical and gene expression analysis (T0). Then, all alveolar sockets were grafted with MgHA. After 4 months (T1), bone samples were harvested for histomorphometrical, immunohistochemical and gene expression analysis. Gene expression and protein expression were evaluated for: RANK, RANKL, OPG, IL-6, TNF-α.

Results: For all markers, gene expression increased, but not significantly, from T0 to T1. The mean RANKL/OPG ratio was 1.88±1.24. Protein expression increased significantly (p<0.05) for TNF-α, IL-6, RANK and RANKL. Histomorphometrical features at T1 were not significantly related to protein expression at T0.

Conclusions: After ridge preservation with MgHA, markers for bone catabolism were activated. No significant correlation was found between histomorphometrical features of the regenerated tissue and protein expression at baseline.

Keywords: Alveolar socket preservation; Bone regeneration; IL-6; Immunohistochemistry; Magnesium-enriched hydroxyapatite; RANK/RANKL/OPG; TNF-α.