Introduction The quality of bond between composite and hard dental tissue is most commonly
estimated on the basis of strength of bond or absence of marginal gap along restoration border.
Marginal index (MI) is a significant indicator of the efficiency of the bond between material
and dental tissue because it also shows the values of width and length of marginal gap.
The aim of this paper was to estimate quantitative and qualitative features of the bond between
composite resin and enamel and dentin, and to determine the values of MI in enamel after application
of two techniques of photopolymerization of composite and two composite adhesive
systems. Also, the impact of longevity of photopolimerization on genotoxicity of composite
adhesives has been investigated.
Material and methods Forty Class V cavities were prepared and restored for scanning electron
microscope (SEM) analysis of composite bonding to enamel and dentin. Adhesion to enamel
and dentin was secured by etch and rinse procedu...re (adhesive-Adper Single Bond 2-ASB/3M
ESPE), i.e. by self etch primer/adhesive (Adper Easy One-AEO/3M ESPE). Photopolymerization
of composite resin (Filtek Ultimate-3M ESPE) was performed using standard halogen
light or gradually, using soft start program. Genotoxyciti of adhesives was invastigated using
Comet assay.
Results The smallest average MI was determined with gradual light curing and application
of ASB/FU material. Qualitative analysis showed better marginal adaptation after application
of etch and rinse adhesive technique and gradual light curing, compared to self etch adhesive
technique and standard photoactivation.
Dentin did not show significant differences in the bond between composite restorations and
dentine tissue compared to light curing technique but significant difference were determined
with respect to the type of adhesive composite material (adhesive technique). Dentin also
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showed a better quality of the composite bond with etch and rinse adhesive technique, regardless
of light curing technique.
Using Comet assay it was concluded that significant lower genotoxicity showed both adhesives
after photopolymerization in duration of 40 seconds compared to 10 seconds.
Conclusion The best marginal adaptation of composite (lowest MI) to enamel and dentin was
obtained with gradual soft start photoactivation in etch and rinse adhesive technique and ASB/
FU material. The best marginal adaptation of composite (lowest MI) for dentin was also determined
with etch and rinse adhesive technique and the same material, regardless of photopolymerization
technique. Longer duration (40 sek) of photoactivation of adhesives in regard to
recommendations of manufactures (10 sek.) contributs to lowering of their genocitotoxicity.
