title: In vitro evaluation of modified surface microhardness measurement, focus variation 3D microscopy and contact stylus profilometry to assess enamel surface loss after erosive-abrasive challenges.
abstract: The aim of the study was to compare surface loss values after erosion-abrasion cycles obtained with modified surface microhardness measurement (mSMH), focus variation 3D microscopy (FVM) and contact stylus profilometry (CSP). We cut human molars into buccal and lingual halves, embedded them in resin and ground 200 μm of enamel away. The resulting surfaces were polished. To maintain a reference area, we applied Block-Out resin to partly cover the enamel surface. The samples were incubated in artificial saliva (37°C; 1 h), then rinsed in deionized water (10 s) and dried with oil-free air (5 s). We immersed the specimens individually in 30 mL citric acid (1%, pH 3.6) for 2 min (25°C, 70 rpm dynamic conditions) before brushing them (50 strokes, 200 g) in an automatic brushing machine with toothpaste-slurry. We calculated the surface loss as per mSMH, by re-measuring the length of the same six indentations made before the abrasive challenge. The experiment consisted of five experimental groups that received between 2 and 10 erosion-abrasion cycles. Each group contained 15 specimens and samples in groups 1, 2, 3, 4 and 5 underwent a total of 2, 4, 6, 8 and 10 cycles, respectively. The resin was removed from the reference area in one piece under 10× magnification and the FVM and CSP were performed. Agreement between the methods was calculated with the intraclass correlation coefficient (ICC) and depicted in Bland-Altman plots. All methods presented a linear pattern of surface loss measurements throughout the experiment, leading overall to a strong, statistically significant correlation between the methods (ICC = 0.85; p<0.001). So, despite the different surface loss values, all methods presented consistent results for surface loss measurement.
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland.|Faculty of Dentistry, Department of Conservative Dentistry, Semmelweis University, Budapest, Hungary.
authors.forename: Milán
authors.identifier: http://orcid.org/0000-0002-7561-6032
authors.initials: M
authors.lastname: Gyurkovics
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland.
authors.forename: Tommy
authors.initials: T
authors.lastname: Baumann
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland.
authors.forename: Thiago Saads
authors.initials: TS
authors.lastname: Carvalho
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland.|Federal University of Rio Grande do Sul, School of Dentistry, Pediatric Dentistry Division, Porto Alegre, Brazil.
authors.forename: Cristiane Meira
authors.initials: CM
authors.lastname: Assunção
authors.affiliation: Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Bern, Switzerland.
authors.forename: Adrian
authors.initials: A
authors.lastname: Lussi
mesh_terms: D003743:Dental Enamel / Q000473:pathology; D006244:Hardness; D006801:Humans; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D008853:Microscopy / Q000379:methods; D008963:Molar / Q000473:pathology; D013499:Surface Properties; D014072:Tooth Abrasion / Q000473:pathology*; D014077:Tooth Erosion / Q000473:pathology*