Acid resistance of human enamel in vitro after bicarbonate application during remineralization.
OBJECTIVE
The aim of this study was to investigate the acid resistance of subsurface enamel lesions remineralized with bicarbonate solutions during remineralization.


METHODS
Two experiments were carried out. In experiment 1, mineral uptake and acid resistance of remineralized enamel lesions were analyzed quantitatively by microradiography for mineral changes. Bicarbonate solutions of 0.5, 5.0 and 50.0 mM were used. In experiment 2, to clarify acid resistance mechanisms, the pH changes in demineralizing solutions on the remineralized enamel surfaces were measured continuously. Only a bicarbonate solution of 5.0 mM was used.


RESULTS
In experiment 1, the bicarbonate-treated groups were more acid resistant than the non-treated groups (p<0.05). However, no statistically significant difference was observed among the different concentrations of bicarbonate. In experiment 2, the pH rise of the bicarbonate group was greater than the other groups.


CONCLUSIONS
It was found that bicarbonate-treated enamel lesions were resistant to acid. It would suggest that bicarbonate ions applied during remineralization may have penetrated into the subsurface lesions. These ions may have worked as buffer agents against the acid challenge and inhibited the decrease in pH.
Tanaka
K
K
Department of Public Health, School of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, 814-0180, Fukuoka, Japan. k-tanaka@fukuoka-u.ac.jp
Iijima
Y
Y
D000143:Acids / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002021:Buffers; D002648:Child; D003743:Dental Enamel / Q000737:chemistry / Q000187:drug effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D012463:Saliva / Q000737:chemistry; D017693:Sodium Bicarbonate / Q000494:pharmacology* / Q000627:therapeutic use; D018709:Statistics, Nonparametric; D017001:Tooth Demineralization / Q000517:prevention & control*; D014089:Tooth Remineralization
D000143:Acids; D002021:Buffers; D017693:Sodium Bicarbonate