Inhibitory Effects of Nitrite on Acid Production in Dental Plaque in Children.
OBJECTIVE
To assess the inhibitory effects of nitrite on plaque acidogenicity and its relationship with caries experience.


METHODS
Plaque (2 μl) was collected from 76 children (age 5.8 ± 2.6 years, dmft 2.9 ± 3.5, DMTF 0.6 ± 1.4) and mixed with nitrite solution (final concentration = 0.63 mM) or distilled water (control). The initial pH (pH-0) of each sample was measured using a portable pH meter. The samples were incubated for 10 min, then their pH (pH-1) was measured again. Next, glucose (final concentration = 0.67%) was added to the samples, which were then incubated for a further 10 min before their pH was assessed for a third time (pH-2).


RESULTS
The pH-0, pH-1, and pH-2 values of the control samples were 7.25 ± 0.16, 6.07 ± 0.44, and 5.11 ± 0.48, respectively, and those of the nitrite-treated samples were 7.26 ± 0.16, 6.37 ± 0.45, and 5.34 ± 0.48, respectively. The pH-1 and pH-2 values of the nitrite-treated samples were higher than those of the control samples (p < 0.005). Greater plaque acid production was associated with stronger inhibition of plaque acid production by nitrite (p < 0.005). No relationship was detected between the inhibition by nitrite and caries experience.


CONCLUSIONS
Nitrite inhibited both endogenous and exogenous plaque acid production. Nitrite inhibited acid production more markedly in plaque that exhibited greater acid production, suggesting that nitrite might be effective at preventing caries, as it contributes to pH homeostasis in plaque by countering excess acidification.
Yuji
Y
Yamamoto
Jumpei
J
Washio
Koichi
K
Shimizu
Koei
K
Igarashi
Nobuhiro
N
Takahashi
D000143:Acids / Q000037:antagonists & inhibitors*; D002648:Child; D002675:Child, Preschool; D003731:Dental Caries / Q000378:metabolism; D003773:Dental Plaque / Q000378:metabolism*; D006801:Humans; D009573:Nitrites / Q000494:pharmacology*
D000143:Acids; D009573:Nitrites