Cytotoxicity of MB-PDT on streptococcus mutans and the effects of MB-PDT on caries development
ZHANG Lei
LU Zhi-shan
MENG Lei
LIU Xue
JING Xiao-yan
Abstract：AIM:To investigate the effects of photodynamic therapy( PDT) of different energy densities with methylene blue( MB) as photosensitizer on streptococcus mutans( S. mutans) in vitro. METHODS:Fifty-six 22 d old Wistar rats were fed with streptococcus mutans to establish dental caries. The rats were then randomly divided into 7 groups(n=8) and received different treatments: MB-PDT with irradiation time of 120 s, 240 s, 480 s, MB only, PDT only, 2 g/L NaF(positive control), and 0. 9% normal saline(negative control), respectively. The rats were trea-ted once a week for 8 weeks. CFU of S. mutans was observed by plate colony count method. The Keyes caries score method was used to observe the the development of dental caries. Tooth surface structure was observed by scanning e-lectron microscopy ( SEM) . RESULTS:MB-PDT significantly reduced the number of S. mutans in the rats oral cavity (P<0. 05). Keyes caries score showed a decreasing trend of caries incidence(P<0. 05). SEM results showed that MB-PDT irradiation could seal the demineralization holes on enamel surface. CONCLUSION:MB-PDT has bacteri-alcidal effect on S. mutans, and can close demineralized hole on enamel surface. The effect is positively related to ex-posure time.
Keywords：photodynamic therapymethylene bluestreptococcus mutans
Publication Date：2015-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 544-548 )