Van Loveren C, Van de Plassche-Simons Y M, De Soet J J, De Graaff J, Ten Cate J M
Academic Centre for Dentistry, Amsterdam, The Netherlands.
Oral Microbiol Immunol. 1991 Oct;6(5):288-91. doi: 10.1111/j.1399-302x.1991.tb00494.x.
The velocity of acid production (Vap) of Streptococcus mutans C180-2 and of 2 fluoride-resistant mutant strains S. mutans C180-2FR and S. mutans C180-2MFR was examined in vitro at pH values between 7.0 and 4.5. The Vap of the fluoride-resistant mutants was lower than the Vap of the parent strain at pH greater than or equal to 6.0. At pH 5.5 and 5.0, the Vap of the mutant strains was higher than the Vap of the parent strain, whereas at pH 4.5 no significant differences were observed between the Vap of the 3 strains. The fluoride sensitivity of all 3 strains was amplified by a low pH environment. The fluoride concentration necessary to inhibit the acid production of the parent strain completely was 27 mM at pH 7 and 0.1 mM at pH 4.5. For the 2 mutants, the corresponding concentrations were 65 mM at pH 7 and 0.5-0.7 mM at pH 4.5. The results suggest that, if S. mutans acquires fluoride resistance in vivo, the rate of acid production in dental plaque may be decreased at pH greater than or equal to 6, but increased at lower pH levels. Low concentrations of fluoride inhibit acid production less effectively.
在体外检测了变形链球菌C180 - 2以及2株耐氟突变株变形链球菌C180 - 2FR和变形链球菌C180 - 2MFR在pH值介于7.0和4.5之间时的产酸速度（Vap）。在pH大于或等于6.0时，耐氟突变株的Vap低于亲本菌株的Vap。在pH 5.5和5.0时，突变株的Vap高于亲本菌株的Vap，而在pH 4.5时，3株菌株的Vap之间未观察到显著差异。低pH环境增强了所有3株菌株对氟的敏感性。完全抑制亲本菌株产酸所需的氟浓度在pH 7时为27 mM，在pH 4.5时为0.1 mM。对于2个突变株，相应的浓度在pH 7时为65 mM，在pH 4.5时为0.5 - 0.7 mM。结果表明，如果变形链球菌在体内获得耐氟性，在pH大于或等于6时，牙菌斑中的产酸速度可能会降低，但在较低pH水平时会增加。低浓度的氟抑制产酸的效果较差。
