Effects of Self-etching Primers on Primary Dentin

Objective: The different structural characteristics of primary from permanent dentin have rised questions on the effect of self-etching adhesives for the treatment of primary dentition. The aim of the present study was to investigate the chemical and morphological alterations induced on primary dentin after treatment with L-Pop (LP), One Up Bond F (OB), SE Bond (SE) and Tyrian SPE (TS).Methods: The crowns of extracted primary molars were horizontally sectioned and the pulpal surfaces were analyzed by reflection FTIR microscopy and ESEM. Then the samples were treated with the self-etching primers, rinsed with ethanol and water and analyzed again. A 37% phosphoric acid etchant (PA) was used as a reference. From the FTIR spectra the mineral to matrix ratio (v1PO4 1000cm-1/amide I 1655 cm-1) was used to assess the extent of demineralization after treatment relative to the non-etched native control. Three regions were analyzed per sample and the results were subjected to t-test (before/after treatment ) and ANOVA (among treatments). Results:The extent of dentin demineralization was (%): LP:100, OB:73.5(8.2), SE:61.2(5.4), TS:100, PA:100. In all treatments ESEM imaging revealed opened and funneled tubules and increased intertubular porosity. The effect was more pronounced in LP, TS and PA agents that caused significantly greater extent of demineralization. Comparison of the results of the present study with the results previously reported for permanent dentin treated with the same agents shows that the “mild” agents (OB and SE) induce greater demineralization on primary dentin. Conclusion: As primary dentin is less mineralized, the use of self-etching agents under the standard application protocols provided by the manufacturers may be considered as quite aggressive and may require revision.