Abstract:

Objective:The study is designed to compare the effects of Lanthanum (La), Calcium (Ca), Fluoride (F) on pHchanges of plaque, and to discuss the anti -cariogenic mechanisms of Lanthanum in terms of metabolism.Methods:Plaque pHvalues after sucrose solution (containing La3+, Ca2+, F-) rinse were measured contiguously usingmicro-touchmethod, and then the mini- mum pH, time of minimum pH, ranges of plaque pH($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 pHvalue in the control group fell down the mostobvious, and the second was thatin the Ca group. The pHvalue decreased the leastin the F and La group, and there was no significant difference between the F and La group. The time of minimum pHwas the same in each group.Conclusion:Ca, La, F can decrease the range of plaque pHdrop after sucrose solution rinse. The degree of Cawas the weakest, and F and Lawere same. All the above evidences prove that La may inhibit the acidogenicity of plaque.

Key words: lanthanum, calcium, fluorides, plaque pH