Effect of active pretreatment of self-etching primers on the ultramorphology of intact primary and permanent tooth enamel.

PURPOSE: The objective of this study was to evaluate the ultramorphological changes after agitated and nonagitated application of self-etching primer systems on unground primary and permanent enamel.
METHODS: Five self-etching primer systems were used: (1) Clearfil SE Bond; (2) Clearfil Protect Bond; (3) Adper Prompt; (4) Xeno III; and (5) nonrinse conditioner (NRC). Noncarious human primary and permanent incisors were collected and stored frozen until used. Intact labial surfaces were divided into 2 halves, applying the self-etching primers with (active application) and without (inactive agitation) using a microbrush within the times recommended by the manufacturers. Treated surfaces were further processed for ultramorphological evaluation under scanning electron microscope (SEM).
RESULTS: All tested self-etching systems produced weaker etch patterns and less dissolution of enamel surface compared with acid-etched samples in both primary and permanent teeth. Except for NRC and Adper Prompt, agitation of the surface did not increase the etching efficacy. Clearfil SE Bond and Clearfil Protect Bond resulted in similar morphological features following application in either mode.
CONCLUSION: While agitation of self-etching primers may improve etching efficacy, this effect appears to be dependent on the material used. Phosphoric acid produces well-defined etching patterns on intact primary and permanent enamel.