An in vitro synergetic evaluation of the use of nisin and sodium fluoride or chlorhexidine against Streptococcus mutans

► Nisin and NaF combination had a synergetic effect against S. mutans, but no interaction between nisin and CHX. ► S. mutans survival showed a significant decline after treatment with nisin and NaF in combination. ► Nisin in combination with NaF possesses strong bactericidal effects on S. mutans in biofilm. ► S. mutans with the treatment of nisin and NaF in combination was severely damaged.