Failed bonded interfaces submitted to microcosm biofilm caries development

This study aimed to evaluate the dentin wall carious lesion development of different composite-dentin interfaces in the presence of two adhesive bonding materials in the gaps, using a microcosm biofilm model.

Dentin samples were prepared (10.4mm(2)) and restored with a composite resin using two adhesive systems (etch-and-rinse and self-etch techniques). Different conditions with respect to composite-dentin interfaces were produced with a 200μm gap: failed bonded without ageing or after mechanical ageing, or non-bonded with or without the presence of adhesive material on the dentin wall. For cariogenic challenge, specimens were subjected to a biofilm microcosm model for 14days to create caries-like wall lesions. Before and after caries development, transverse wavelength-independent microradiography images were taken, and lesion depth and mineral loss were measured. Data were analysed with linear regression models (p<0.05).

The composite-dentin interface conditions significant influenced the caries development: lesion development was reduced by the presence of the adhesive material on dentin wall, while lesion development was increased by the mechanical ageing (p=0.019). There was no difference between the adhesive materials (p values>0.05).

Different composite-dentin interfaces influence wall lesion development in gaps, with the interfaces submitted to ageing showing less carious protection than those interfaces with the presence of adhesive covering the dentin.

The presence of adhesive bonding material in the gaps plays a role on the wall caries lesion development.