[Induction of fluoride-resistant mutant of S. mutans and the measurement of its acidogenesis in vitro].
OBJECTIVE
To induce fluoride-resistant mutant of S. mutans in vitro and find out the differences of cariogenicity between them.


METHODS
Fluoride-resistant strain Ingbritt-FR was obtained by subculturing S. mutans Ingbritt to TSA and TSB containing different concentrations of fluoride. Lactic production and terminal pH of media were measured by gas chromatography method.


RESULTS
1. The stable fluoride-resistant mutant of S. mutans Ingbritt had been induced successfully in vitro; 2. Lactic production of Ingbritt-FR was significantly more than its parent strain at various initial pH values with 0.5 and 5.0 mmol/L fluoride whereas when no fluoride existed, there were two situations: the acid production was more than S. mutans Ingbritt at initial pH above 5.0 while the result was opposite when pH was 5.0 and below.


CONCLUSIONS
The fluoride-resistant strain Ingbritt-FR had a stronger cariogenic potential than its parent strain S. mutans Ingbritt in physiological plaques.
Sheng
J
J
Department of Oral Medicine, School of Stomatology, Shanghai Second Medical University, Shanghai 200011, China.
Liu
Z
Z
D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D005459:Fluorides / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000096:biosynthesis; D009154:Mutation; D013295:Streptococcus mutans / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
D019344:Lactic Acid; D005459:Fluorides