Quantitative light-induced fluorescence to measure enamel remineralization in vitro.
The aim of this study was to compare the ability of quantitative light-induced fluorescence (QLF) and surface microhardness (SMH) to measure the remineralization of enamel subsurface lesions, using a pH-cycling model including treatment with 0-ppm, 550-ppm or 1,100-ppm sodium fluoride (NaF) dentifrices.


METHODS
Subsurface lesions were created in human enamel specimens (n = 36) and exposed to a remineralization pH-cycling model for 14 days. The pH-cycling model was performed in an automated system where specimens were subjected to a demineralizing solution for 20 min and treatment for 1 min and were then remineralized for 7 h 39 min, 3 times daily. The treatments consisted of 3 NaF, silica-containing dentifrices (0 ppm F; 550 ppm F; 1,100 ppm F). The outcome variables were: change from baseline in surface hardness and percentage change from baseline in fluorescence. An ANCOVA explored differences between different treatment groups (at the p < 0.05 level). Associations between QLF and SMH were evaluated using Spearman's correlation coefficient.


RESULTS
The percentage SMH changes were 14.9 ± 2.1%, 56.6 ± 9.6% and 103.9 ± 14.6% for the 0-, 550- and 1,100-ppm F dentifrices, respectively. The percentage fluorescence changes were 15.6 ± 7.1%, 59.8 ± 11.9% and 85 ± 13.2%, respectively. The differences between all pairwise comparisons were statistically significant for both methods (p = 0.001). QLF correlated with SMH (r = 0.67).


CONCLUSIONS
Both the SMH and QLF methods demonstrated a significant F dose response for toothpaste in this in vitro remineralization model, and both methods were able to distinguish treatments with different F levels.
The University of Manchester, School of Dentistry, Colgate-Palmolive Dental Health Unit, Williams House, Manchester Science Park, Lloyd St North, Manchester, M15 6SE, UK.
J
J
Gomez
I A
IA
Pretty
R P
RP
Santarpia
B
B
Cantore
A
A
Rege
I
I
Petrou
R P
RP
Ellwood
D019342:Acetic Acid / Q000009:adverse effects; D000180:Acrylic Resins / Q000627:therapeutic use; D002327:Cariostatic Agents / Q000008:administration & dosage; D003743:Dental Enamel / Q000187:drug effects / Q000473:pathology*; D003802:Dentifrices / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D017886:Durapatite / Q000627:therapeutic use; D005453:Fluorescence; D006244:Hardness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008027:Light; D012969:Sodium Fluoride / Q000008:administration & dosage; D013997:Time Factors; D014089:Tooth Remineralization / Q000379:methods*
D000180:Acrylic Resins; C516894:Carbopol 981; D002327:Cariostatic Agents; D003802:Dentifrices; D012969:Sodium Fluoride; D017886:Durapatite; D019342:Acetic Acid