Mechanical characterization of proanthocyanidin–dentin matrix interaction

Abstract 

Objectives

To characterize the properties of dentin matrix treated with two proanthocyanidin rich cross-linking agents and their effect on dentin bonded interfaces.

Methods

Sound human molars were cut into 0.5mm thick dentin slabs, demineralized and either treated with one of two cross-linking agents (grape seed—GSE and cocoa seed—COE extracts) or left untreated. The modulus of elasticity of demineralized dentin was assessed after 10 or 60min and the swelling ratio after 60min treatment. Bacterial collagenase was also used to assess resistance to enzymatic degradation of samples subjected to ultimate tensile strength. The effect of GSE or COE on the resin–dentin bond strength was evaluated after 10 or 60min of exposure time. Data were statistically analyzed at a 95% confidence interval.

Results

Both cross-linkers increased the elastic modulus of demineralized dentin as exposure time increased. Swelling ratio was lower for treated samples when compared to control groups. No statistically significant changes to the UTS indicate that collagenase had no effect on dentin matrix treated with either GSE or COE. Resin–dentin bonds significantly increased following treatment with GSE regardless of the application time or adhesive system used.

Significance

Increased mechanical properties and stability of dentin matrix can be achieved by the use of PA-rich collagen cross-linkers most likely due to the formation of a PA–collagen complex. The short term resin–dentin bonds can be improved after 10min dentin treatment.

Keywords: Dentin, Collagen, Natural collagen cross-linkers, Bond strength, Mechanical properties