Smear layer deproteinization with NaOCl and HOCl: Do application/wash-out times affect dentin bonding of one-step self-etch adhesives?
Abstract
This study investigated the influence of application/wash-out times of sodium hypochlorite (NaOCl) and hypochlorous acid (HOCl) on dentin bond strength of one-step self-etch adhesives (1-SEAs). Human coronal dentin discs with a standardized smear layer were pretreated with 6% NaOCl or 100 ppm HOCl for 5s, 15s, or 30s, and washed out with water for 5s, 15s or 30s with or without the application of Clearfil DC Activator (CDA).
No pretreatment was used as a control. The discs were bonded with a 1-SEA (Bond Force II or Clearfil Universal Bond Quick) and microtensile bond strength (µTBS) was measured after 24h.
Pretreatment with NaOCl for 15s and 30s significantly decreased µTBS (p<0.05), irrespective of wash-out time. The application of CDA recovered µTBS but did not outperform the control group.
Conversely, pretreatment with HOCl for 15s and 30s followed by 30s wash-out time significantly increased µTBS of 1-SEAs (p<0.05), regardless of CDA application.