title: Impact of experimental nano-HAP pastes on bovine enamel and dentin submitted to a pH cycling model.
abstract: This in vitro study evaluated the preventive potential of experimental pastes containing 10% and 20% hydroxyapatite nanoparticles (Nano-HAP), with or without fluoride, on dental demineralization. Bovine enamel (n=15) and root dentin (n=15) specimens were divided into 9 groups according to their surface hardness: control (without treatment), 20 Nanop paste (20% HAP), 20 Nanop paste plus (20% HAP + 0.2% NaF), 10 Nanop paste (10% HAP), 10 Nanop paste plus (10% HAP + 0.2% NaF), placebo paste (without fluoride and HAP), fluoride paste (0.2% NaF), MI paste (CPP-ACP, casein phosphopeptide-amorphous calcium phosphate), and MI paste plus (CPP-ACP + 0.2% NaF). Both MI pastes were included as commercial control products containing calcium phosphate. The specimens were treated with the pastes twice a day (1 min), before and after demineralization. The specimens were subjected to a pH-cycling model (demineralization-6-8 h/ remineralization-16-18 h a day) for 7 days. The dental subsurface demineralization was analyzed using cross-sectional hardness (kgf/mm 2 , depth 10-220 µm). Data were tested using repeated-measures two-way ANOVA and Bonferroni's test (p<0.05). The only treatment able to reduce the loss of enamel and dentin subsurface hardness was fluoride paste (0.2% NaF), which differed significantly from the control at 30- and 50-µm depth (p<0.0001). The other treatments were not different from each other or compared with the control. The experimental Nanop pastes, regardless of the addition of fluoride, were unable to reduce dental demineralization in vitro.
authors: Department of Biological Sciences, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil.
authors: Livia P
authors: LP
authors: Comar
authors: Beatriz M
authors: BM
authors: Souza
authors: Luiz Fernando
authors: LF
authors: Gracindo
authors: Marília A R
authors: MA
authors: Buzalaf
authors: Ana Carolina
authors: AC
authors: Magalhães
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D002327:Cariostatic Agents / Q000627:therapeutic use; D002364:Caseins / Q000627:therapeutic use; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects*; D003804:Dentin / Q000187:drug effects*; D017886:Durapatite / Q000627:therapeutic use*; D006244:Hardness; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000627:therapeutic use*; D010710:Phosphates / Q000032:analysis; D010919:Placebos; D011897:Random Allocation; D012969:Sodium Fluoride / Q000627:therapeutic use; D013053:Spectrophotometry; D017001:Tooth Demineralization / Q000517:prevention & control*; D014100:Toothpastes / Q000032:analysis / Q000627:therapeutic use*
chemical_list: D002327:Cariostatic Agents; D002364:Caseins; D010710:Phosphates; D010919:Placebos; D014100:Toothpastes; C447032:casein phosphopeptide-amorphous calcium phosphate nanocomplex; D012969:Sodium Fluoride; D017886:Durapatite; D002118:Calcium