Effects of fluoride concentration and temperature of milk on caries lesion rehardening.
OBJECTIVE
The aim of the present in vitro study was to investigate the effects of fluoride concentration and temperature of milk on caries lesion rehardening under pH cycling conditions.


METHODS
Incipient caries-like lesions were formed in human enamel specimens, characterized using Vickers surface microhardness (VHN) and assigned to seven treatment groups (n=18 per group): fluoride was tested at five levels (0, 2.5, 5, 10, 20mg/l, all 22°C) and milk temperature at three levels (4, 22, 60°C), but only for 10mg/l F. Lesions were pH cycled for 15d (4 ×/daily 10 min milk treatments, 1 ×/daily 4h acid challenge, remineralization in human/artificial saliva mixture). VHN of specimens were measured again and changes from lesion baseline were calculated. Subsequently, enamel fluoride uptake (EFU) was determined using the micro drill technique.


RESULTS
Lesions responded to fluoride in a dose-response manner with higher fluoride concentrations resulting in more lesion rehardening (20>10 ≥ 5 ≥ 2.5>0mg/lF). Furthermore, fluoridated milk at 60°C was found to be more efficacious than at 4°C (60 ≥ 22>4°C). EFU results were similar (20>10>5>2.5 ≥ 0 mg/lF; 60>22≥4°C).


CONCLUSIONS
Both fluoride concentration and milk temperature are likely to contribute to the anti-caries potential of fluoridated milk.
Department of Preventive and Community Dentistry, Oral Health Research Institute, Indiana University School of Dentistry, Indianapolis, IN 46202, USA. flippert@iupui.edu
F
F
Lippert
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Martinez-Mier
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Soto-Rojas
D000818:Animals; D002327:Cariostatic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D003731:Dental Caries / Q000378:metabolism / Q000473:pathology*; D003743:Dental Enamel / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005459:Fluorides / Q000008:administration & dosage* / Q000493:pharmacokinetics; D006244:Hardness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008892:Milk; D012463:Saliva / Q000502:physiology; D012464:Saliva, Artificial / Q000737:chemistry; D013696:Temperature; D014089:Tooth Remineralization / Q000379:methods*
D002327:Cariostatic Agents; D012464:Saliva, Artificial; D005459:Fluorides