Hybrid layer morphology on sound and caries-affected primary dentin

Abstract

Introduction: Resin composite is the most suitable esthetic alternative option for primary teeth restoration. Dentists encounter with caries-affected dentin (CAD) nor sound (SD), in every day practice. Caries-affected dentin is uninfected, only partially demineralized and remineralizible under physiological conditions. Morphological features of CAD can affect hybrid layer formation.

The aim of this in vitro study was to evaluate morphology of hybrid layer produced by different adhesive systems on sound and caries-affected primary dentine.

Materials and methods: Forty sound and caries-affected extracted primary molars were used in this study. Teeth from each substrate (SD and CAD) were randomly allocated to 4 groups, according to adhesive systems (Optibonf FL (Kerr), Optibond SoloPlus (Kerr), Single Bond Universal in etch&rinse and self-etch mode (3M)). Hybrid layer morphology and homogeneity, presents of resin tags and gaps were analyzed in each specimen by FE-SEM (JSM-6700F JEОL, Japan). Statistical analysis was conducted with Kruskal-Wallis test (p<0,05).

Results: All adhesives formed clearly visible hybrid layer with numerous resin tags on CAD of primary teeth, even self-etch mode. The resin tags were shorter irregular hybrid layer was porous. The porous zones were visualized beneath the hybrid layer in CAD and etch&rinse adhesive systems. Dentin tubules were often obliterated with rhomboid crystals which wasn’t removed by acid. Some specimens of caries-affected dentin had microcavities, cracks and porosity under hybrid layer. There were no significant differences in hybrid layer thickness between SD and CAD for each adhesive system.

Conclusions: Etch&rinse adhesive systems produce pronounced hybridize complex on sound and caries-affected primary dentin. Dentin substrate and adhesive system type affects hybrid layer formation.