[A comparative study about the influence of lanthanum, calcium, fluoride on plaque pH].
OBJECTIVE
The study is designed to compare the effects of Lanthanum (La), Calcium (Ca), Fluoride (F) on pH changes of plaque, and to discuss the anti-cariogenic mechanisms of Lanthanum in terms of metabolism.


METHODS
Plaque pH values after sucrose solution (containing La3+, Ca2+, F-) rinse were measured contiguously using micro-touch method, and then the minimum pH, time of minimum pH, ranges of plaque pH (delta pH), and areas of the response curves below (AUC6.5) were analyzed using two-way analysis of variance (ANOVA).


RESULTS
No statistical difference was found in the above monitored parameters of 8 subjects. For the decreasing degree of plaque pH, the pH value in the control group fell down the most obvious, and the second was that in the Ca group. The pH value decreased the least in the F and La group, and there was no significant difference between the F and La group. The time of minimum pH was the same in each group.


CONCLUSIONS
Ca, La, F can decrease the range of plaque pH drop after sucrose solution rinse. The degree of Ca was the weakest, and F and La were same. All the above evidences prove that La may inhibit the acidogenicity of plaque.
Liu
D
D
Stomatologic Hospital, Tongji University.
Yuan
S
S
Wang
X
X
D000328:Adult; D002118:Calcium / Q000494:pharmacology*; D003773:Dental Plaque / Q000737:chemistry*; D005260:Female; D005459:Fluorides / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007811:Lanthanum / Q000494:pharmacology*; D008297:Male
D007811:Lanthanum; D005459:Fluorides; D002118:Calcium