Fluoride dose-response of human and bovine enamel artificial caries lesions under pH-cycling conditions.
OBJECTIVE
This laboratory study aimed to (a) compare the fluoride dose-response of different caries lesions created in human and bovine enamel (HE/BE) under pH-cycling conditions and (b) investigate the suitability of Knoop and Vickers surface microhardness (K-SMH/V-SMH) in comparison to transverse microradiography (TMR) to investigate lesion de- and remineralization.


METHODS
Caries lesions were formed using three different protocols (Carbopol, hydroxyethylcellulose-HEC, methylcellulose-MeC) and assigned to 24 groups using V-SMH, based on a 2 (enamel types) × 3 (lesion types) × 4 (fluoride concentrations used during pH-cycling-simulating 0/250/1100/2800 ppm F as sodium fluoride dentifrices) factorial design. Changes in mineral content and structural integrity of lesions were determined before and after pH-cycling. Data were analyzed using three-way ANOVA.


RESULTS
BE was more prone to demineralization than HE. Both enamel types showed similar responses to fluoride with BE showing more remineralization (as change in integrated mineral loss and lesion depth reduction), although differences between tissues were already present at lesion baseline. Carbopol and MeC lesions responded well to fluoride, whereas HEC lesions were almost inert. K- and V-SMH correlated well with each other and with the integrated mineral loss data, although better correlations were found for HE than for BE and for MeC than for Carbopol lesions. Hardness data for HEC lesions correlated only with surface zone mineral density data.


CONCLUSIONS
BE is a suitable surrogate for HE under pH-cycling conditions.


CONCLUSIONS
The in vitro modeling of dental caries is complex and requires knowledge of lesion behavior, analytical techniques, and employed hard tissues.
Department of Preventive and Community Dentistry, Oral Health Research Institute, Indiana University School of Dentistry, 415 Lansing Street, Indianapolis, IN, 46202, USA. flippert@iu.edu.
Frank
F
Lippert
Department of Preventive and Community Dentistry, Oral Health Research Institute, Indiana University School of Dentistry, 415 Lansing Street, Indianapolis, IN, 46202, USA.
Kalp
K
Juthani
D000818:Animals; D002417:Cattle; D003731:Dental Caries / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D003743:Dental Enamel / Q000378:metabolism* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005459:Fluorides / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male
D005459:Fluorides
Bovine enamel; Dental caries; Human enamel; Surface microhardness; Transverse microradiography; pH-cycling