Photoinhibition of streptococcus mutans biofilm-induced lesions in human dentin by violet-blue light

Grace Gomez Felix Gomez, Frank Lippert, Masatoshi Ando, Andrea F. Zandona, George J. Eckert, Richard L. Gregory

Research output: Contribution to journalArticle


This in vitro study determined the e_ectiveness of violet-blue light on Streptococcus mutans (UA159) biofilm induced dentinal lesions. Biofilm was formed on human dentin specimens in a 96-well microtiter plate and incubated for 13 h in the presence of tryptic soy broth (TSB) or TSB supplemented with 1% sucrose (TSBS). Violet-blue light (405 nm) from quantitative light-induced fluorescence (QLFTM) was used to irradiate the biofilm. Supernatant liquid was removed, and the biofilm was irradiated continuously with QLF for 5 min twice daily with an interval of 6 h for 5 d, except with one treatment on the final day. Colony forming units (CFU) of the treated biofilm, changes in fluorescence (DF; QLF-Digital BiluminatorTM), lesion depth (L), and integrated mineral loss (DZ; both transverse microradiography) were quantified at the end of the fifth day. Statistical analysis used analysis of variance (ANOVA), testing at a 5% significance level. In the violet-blue light irradiated groups, there was a significant reduction (p < 0.05) of bacterial viability (CFU) of S. mutans with TSB and TSBS. Violet-blue light irradiation resulted in the reduction of DF and L of the dentinal surface with TSBS. These results indicate that violet-blue light has the capacity to reduce S. mutans cell numbers.

Original languageEnglish (US)
Article numberdj7040113
JournalDentistry Journal
Issue number4
StatePublished - Dec 2019


  • Dental caries
  • Phototherapy
  • Streptococcus mutans
  • Violet-blue light

ASJC Scopus subject areas

  • Dentistry(all)

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