title: Quantitative assessment of the efficacy of amorphous calcium phosphate/methacrylate composites in remineralizing caries-like lesions artificially produced in bovine enamel.
abstract: Recent studies show that methacrylate-based composites with amorphous calcium phosphate (ACP) as a filler can release supersaturating levels of calcium and phosphate ions in proportions favorable for apatite formation. These findings suggest that such composites could be effectively used as coatings for remineralizing teeth damaged by tooth decay. To examine this hypothesis, we tested composites in vitro for their efficacy to remineralize artificially formed caries-like lesions in extracted bovine incisors. Single 120-microns-thick sagittal tooth sections were placed in holders that exposed only the carious enamel surface. The exposed surfaces were coated with a 1-mm- to 1.5-mm-thick layer of the composite containing, by mass, 40% apatite, silica, or P2O7(-4)-stabilized ACP and 60% photoactivated resin comprised of Bis-GMA, TEGDMA, HEMA, and ZrM. The photocured composite-coated sections were immersed either in a remineralizing solution for 4 weeks at 37 degrees C (static model) or cyclically immersed in demineralizing (0.5 h) and remineralizing solutions (11.5 h) for 2 weeks (dynamic model). Quantitative digital image analysis of matched 102 microns x 220 microns areas from contact microradiographs taken of the sections before and after immersion showed that lesions coated with ACP-filled composites fractionally recovered 71% +/- 33% of their lost mineral compared with 14% +/- 13% for apatite controls in the static model and 38% +/- 16% compared with -6% +/- 24% in the dynamic model. The results suggest that sealants based on ACP-filled methacrylate composites have the potential to remineralize carious enamel lesions.
authors.affiliation: Bone Research Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: D
authors.initials: D
authors.lastname: Skrtic
authors.forename: A W
authors.initials: AW
authors.lastname: Hailer
authors.forename: S
authors.initials: S
authors.lastname: Takagi
authors.forename: J M
authors.initials: JM
authors.lastname: Antonucci
authors.forename: E D
authors.initials: ED
authors.lastname: Eanes
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000627:therapeutic use*; D002417:Cattle; D003188:Composite Resins / Q000627:therapeutic use*; D003731:Dental Caries / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism; D003743:Dental Enamel / Q000737:chemistry / Q000000981:diagnostic imaging / Q000187:drug effects*; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D066298:In Vitro Techniques; D008689:Methacrylates / Q000627:therapeutic use*; D008852:Microradiography; D012822:Silicon Dioxide / Q000627:therapeutic use; D014089:Tooth Remineralization / Q000379:methods* / Q000706:statistics & numerical data; D014131:Trace Elements / Q000032:analysis
chemical_list: D002130:Calcium Phosphates; D003188:Composite Resins; D008689:Methacrylates; D014131:Trace Elements; C485828:alpha-tricalcium phosphate; C519480:amorphous calcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; D012822:Silicon Dioxide; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous