Effects of combined exogenous dextranase and sodium fluoride on Streptococcus mutans 25175 monospecies biofilms.
OBJECTIVE
To investigate the effects of exogenous dextranase and sodium fluoride on a S. mutans monospecies biofilm.


METHODS
S. mutans 25175 was grown in tryptone soya broth medium, and biofilm was formed on glass slides with 1.0% sucrose. Exogenous dextranase and sodium fluoride were added alone or together. The biofilm morphology was analyzed by confocal laser scanning microscopy. The effects of the drug on the adhesion and exopolysaccharide production by the biofilms were evaluated by scintillation counting and the anthrone method, respectively.


RESULTS
In this study, we found that the structure of initial biofilm and mature biofilm were partly altered by dextranase and high concentrations of sodium fluoride separately. However, dextranase combined with a low concentration of sodium fluoride could clearly destroy the typical tree-like structure of the biofilm, and led to less bacterial adhesion than when the dextranase or fluoride were used alone (P < 0.05). The amounts of soluble and insoluble exopolysaccharide were significantly reduced by combining dextranase with a low concentration of sodium fluoride, much more than when they were used alone (P < 0.05). These data indicate that dextranase and a low concentration of sodium fluoride may have synergistic effects against S. mutans biofilm and suggest the application of a low concentration of sodium fluoride in anticaries treatment.
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 14 South Renmin Road, Section 3, Chengdu, Sichuan 610041, PR China.
Ying-Ming
YM
Yang
The Affiliated Hospital of Stomatology, Chongqing Medical University, PR China.
Dan
D
Jiang
Tianjin Stomatological Hospital, Tianjin, PR China.
Yuan-Xin
YX
Qiu
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 14 South Renmin Road, Section 3, Chengdu, Sichuan 610041, PR China.
Rong
R
Fan
Department of Endodontics, Capital Medical University School of Stomatology, Beijing, PR China.
Ru
R
Zhang
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 14 South Renmin Road, Section 3, Chengdu, Sichuan 610041, PR China.
Mei-Zhi
MZ
Ning
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 14 South Renmin Road, Section 3, Chengdu, Sichuan 610041, PR China.
Mei-Ying
MY
Shao
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 14 South Renmin Road, Section 3, Chengdu, Sichuan 610041, PR China.
Chao-Liang
CL
Zhang
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 14 South Renmin Road, Section 3, Chengdu, Sichuan 610041, PR China.
Xiao
X
Hong
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 14 South Renmin Road, Section 3, Chengdu, Sichuan 610041, PR China.
Tao
T
Hu
D001422:Bacterial Adhesion / Q000187:drug effects; D001431:Bacteriological Techniques; D018441:Biofilms / Q000187:drug effects*; D002327:Cariostatic Agents / Q000494:pharmacology*; D003910:Dextranase / Q000494:pharmacology*; D004338:Drug Combinations; D004357:Drug Synergism; D006801:Humans; D018613:Microscopy, Confocal; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D012969:Sodium Fluoride / Q000494:pharmacology*; D012995:Solubility / Q000187:drug effects; D013295:Streptococcus mutans / Q000187:drug effects* / Q000502:physiology; D013395:Sucrose / Q000494:pharmacology
D002327:Cariostatic Agents; D004338:Drug Combinations; D011135:Polysaccharides, Bacterial; D013395:Sucrose; D012969:Sodium Fluoride; D003910:Dextranase