Impact of N-acetylcysteine (NAC) and calcium hydroxide intracanal medications in primary endodontic infection: a randomized clinical trial

Objectives This RCT investigated the impact of N-acetylcysteine (NAC) and calcium hydroxide [Ca(OH)(2)] intracanal medications (ICMs) in primary endodontic infection with apical periodontitis (PEIAP). Materials and methods Thirty-six teeth with PEIAP were randomly divided into groups according to the ICM: NAC, Ca(OH)(2) + saline solution (SSL), and Ca(OH)(2) + 2% chlorhexidine-gel (2% CHX-gel) (all, n= 12). Root canal samples (RCSs) were collected before (s1) and after instrumentation (s2) and after 14 days of ICM (s3). Chemomechanical preparation (CMP) was performed with a Reciproc file and 2.5% NaOCl. Checkerboard DNA-DNA hybridization was used to assess 40 target bacteria species. Results At s1, bacterial DNA was detected in 100% of RCSs (36/36). All 40 bacterial species were found in PEIAP. The mean number of species per RCS was 17.92 +/- 13.18. The most frequent bacteria were S. mitis (65%), E. nodatum (63%), E. faecalis (63%), F. nucl sp vicentii (58%), T. forsythia (58%), and F. periodonticum (56%). CMP reduced the mean number of species per RCS to 6.8 +/- 2.36 (p < 0.05). At s3, the intragroup analysis revealed a broader antimicrobial activity for Ca (OH)(2) + 2% CHX-gel and NAC than Ca(OH)(2) + SSL (p < 0.05). NAC eliminated 8/12 bacteria species resistant to both Ca (OH)2 ICMs, including P. micra, P. nigrescens, T. denticola, A. israelii, P. endodontalis, P. acnes, C. ochracea, and E. corrodens. Conclusions Ca (OH)2 + 2% chlorhexidine gel (2% CHX gel) showed a greater bacterial elimination over the number of bacterial species; however, NAC eliminated 8/12 bacteria species resistant to both Ca (OH)2 ICMs (RBR-3xbnnn).

Automated summary

This study investigated the impact of NAC and Ca(OH)(2) intracanal medications (ICMs) on primary endodontic infection with apical periodontitis (PEIAP). The results showed that NAC was effective in eliminating bacterial species that were resistant to both ICMs.