Measurement of enamel remineralization using microradiography and confocal microscopy. A correlational study.
Tooth minerals are lost and regained constantly in a normal, human oral environment. Different methods have been developed to measure this gain and loss in enamel minerals; however, these methods deal with different problems, such as being time consuming or involving the use of X-rays. The aim of this study was to determine if remineralization measured in a thin enamel section (TS) by transversal microradiography (MR) can be reliably monitored by measuring lesion parameters (area, total and average dye fluorescence) on the same TS or on half a tooth (HT) with confocal laser scanning microscopy (CLSM). Thirty-six human enamel specimens were demineralized for 96h, and then half of each specimen was covered with an acid-resistant nail varnish. Specimens were divided into three groups (12/group) and subjected for 20 days to a cyclic remineralization regimen with consisted daily of a 4-hour acid challenge, four 1-min treatment periods with 0, 250 or 1,100 ppm F dentifrice slurries (1:2; dentifrice:water) and 20 h in pooled, human saliva, at room temperature. Specimens were cut and analyzed by MR, then stained with a fluorescent dye (0.1mM rhodamine B) for 1 h and analyzed using CLSM. Both MR and CLSM detected significantly greater remineralization (p<0.05) in the specimens treated with the fluoride-containing dentifrices than in the specimens treated with 0 ppm F. Significant differences were detected between specimens treated witht the fluoride-containing dentifrices by MR and CLSM (HT area and total fluorescence). Statistically significant (p<0.05) Pearson correlation coefficients were calculated between the MR and CLSM data: difference in MR mineral content (DeltaM) versus HT lesion area = 0.71; DeltaM versus HT total fluorescence = 0.70; DeltaM versus HT average fluorescence = 0.61; DeltaM versus TS lesion area = 0.88; DeltaM versus TS total fluorescence = 0.63, and DeltaM versus TS average fluorescence = 0.40. It is concluded that confocal microscopy in either TS or HT may provide valid surrogates (area and total fluorescence) for MR measurements in enamel remineralization studies.
Oral Health Research Institute, School of Dentistry, Indiana University, Indianapolis, Ind., USA. CHARLGONZ@IUSD.IUPUI.EDU
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González-Cabezas
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Fontana
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Dunipace
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Li
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Fischer
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Proskin
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GK
Stookey
D000704:Analysis of Variance; D002327:Cariostatic Agents / Q000494:pharmacology; D003743:Dental Enamel / Q000737:chemistry* / Q000000981:diagnostic imaging / Q000648:ultrastructure; D003802:Dentifrices / Q000494:pharmacology; D005456:Fluorescent Dyes; D005459:Fluorides / Q000494:pharmacology; D006801:Humans; D008852:Microradiography; D018613:Microscopy, Confocal; D008903:Minerals / Q000032:analysis*; D010919:Placebos; D015203:Reproducibility of Results; D012235:Rhodamines; D012463:Saliva / Q000502:physiology; D017001:Tooth Demineralization / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D014089:Tooth Remineralization
D002327:Cariostatic Agents; D003802:Dentifrices; D005456:Fluorescent Dyes; D008903:Minerals; D010919:Placebos; D012235:Rhodamines; D005459:Fluorides