title: Effect of resin infiltration on the nanomechanical properties of demineralized bovine enamel.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the efficacy of resin infiltration in preventing in vitro lesion progression.
  
  
  METHODS
  Buccal surfaces of bovine incisors were divided into mesial and distal regions and, at the center, nail varnish was applied (1.0 mm width) to protect the enamel surface against any further treatment. In order to create artificial enamel lesions in the unprotected areas, each specimen was soaked in a demineralizing solution. After that, specimens had two enamel lesions. One lesion in each sample was etched with 15% HCl for 120 s and infiltrated with a commercial infiltrating resin for 3 min, while the other lesion was not treated (control). Each specimen was cross-sectionally halved and randomly allocated to two groups: Group 1 was immediately processed and Group 2 was submitted to a new demineralization process. The samples were analyzed by means of cross-sectional hardness measurements using a nanoindenter equipment. Hardness data were statistically analyzed by non-parametric Kruskal-Wallis and MannWhitney tests (α = 0.05).
  
  
  RESULTS
  The findings showed statistical difference between treatments at the same analyzed distance range from the outer surface of the enamel (P < 0.05).
  
  
  CONCLUSIONS
  The untreated lesion showed lower hardness values for distances near the outer surface of the enamel. The resin infiltration was efficient in preventing further in vitro demineralization of bovine enamel lesions.
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Fluminense Federal University, Niterói, RJ, Brazil.
authors.forename: Mônica Almeida
authors.initials: MA
authors.lastname: Tostes
authors.affiliation: Department of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Santos
authors.affiliation: Department of Metallurgical and Materials Engineering, COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Sérgio Alvaro
authors.initials: SA
authors.lastname: Camargo
keywords: Dental caries; dental enamel; hardness