title: Comparison of cross-sectional hardness and transverse microradiography of artificial carious enamel lesions induced by different demineralising solutions and gels.
abstract: The aims of this study were: (1) to correlate surface (SH) and cross-sectional hardness (CSH) with microradiographic parameters of artificial enamel lesions; (2) to compare lesions prepared by different protocols. Fifty bovine enamel specimens were allocated by stratified randomisation according to their initial SH values to five groups and lesions produced by different methods: MC gel (methylcellulose gel/lactic acid, pH 4.6, 14 days); PA gel (polyacrylic acid/lactic acid/hydroxyapatite, pH 4.8, 16 h); MHDP (undersaturated lactate buffer/methyl diphosphonate, pH 5.0, 6 days); buffer (undersaturated acetate buffer/fluoride, pH 5.0, 16 h), and pH cycling (7 days). SH of the lesions (SH(1)) was measured. The specimens were longitudinally sectioned and transverse microradiography (TMR) and CSH measured at 10- to 220-microm depth from the surface. Overall, there was a medium correlation but non-linear and variable relationship between mineral content and radicalCSH. radicalSH(1) was weakly to moderately correlated with surface layer properties, weakly correlated with lesion depth but uncorrelated with integrated mineral loss. MHDP lesions showed the highest subsurface mineral loss, followed by pH cycling, buffer, PA gel and MC gel lesions. The conclusions were: (1) CSH, as an alternative to TMR, does not estimate mineral content very accurately, but gives information about mechanical properties of lesions; (2) SH should not be used to analyse lesions; (3) artificial caries lesions produced by the protocols differ, especially considering the method of analysis.
authors.affiliation: Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil. acm@usp.br
authors.forename: A C
authors.initials: AC
authors.lastname: Magalhães
authors.forename: B M
authors.initials: BM
authors.lastname: Moron
authors.forename: L P
authors.initials: LP
authors.lastname: Comar
authors.forename: A
authors.initials: A
authors.lastname: Wiegand
authors.forename: W
authors.initials: W
authors.lastname: Buchalla
authors.forename: M A R
authors.initials: MA
authors.lastname: Buzalaf
mesh_terms: D000085:Acetates / Q000009:adverse effects; D000180:Acrylic Resins / Q000009:adverse effects; D019412:Anatomy, Cross-Sectional; D000818:Animals; D001031:Apatites / Q000494:pharmacology; D002021:Buffers; D002130:Calcium Phosphates / Q000494:pharmacology; D002326:Cariogenic Agents / Q000009:adverse effects*; D002327:Cariostatic Agents / Q000494:pharmacology; D002417:Cattle; D003731:Dental Caries / Q000378:metabolism / Q000473:pathology*; D003743:Dental Enamel / Q000737:chemistry / Q000473:pathology*; D004164:Diphosphonates / Q000009:adverse effects; D017886:Durapatite / Q000009:adverse effects; D005459:Fluorides / Q000494:pharmacology; D005782:Gels; D006244:Hardness; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000009:adverse effects; D008747:Methylcellulose / Q000009:adverse effects; D008852:Microradiography; D011897:Random Allocation; D012996:Solutions; D013997:Time Factors; D017001:Tooth Demineralization / Q000473:pathology; D014089:Tooth Remineralization
chemical_list: D000085:Acetates; D000180:Acrylic Resins; D001031:Apatites; D002021:Buffers; D002130:Calcium Phosphates; D002326:Cariogenic Agents; D002327:Cariostatic Agents; D004164:Diphosphonates; D005782:Gels; D012996:Solutions; C022045:octacalcium phosphate; C029285:hydroxymethanediphosphonic acid; D019344:Lactic Acid; C006903:carbopol 940; D008747:Methylcellulose; D017886:Durapatite; C025105:fluorapatite; C494366:calcium phosphate, dibasic, dihydrate; D005459:Fluorides