title: Uninfiltrated Collagen in Hybrid Layers produced after Reduced Acid-etching Time on Primary and Permanent Dentin.
abstract: OBJECTIVE
  This study evaluated the influence of acid-etching time on collagen exposure in adhesive interfaces established on primary and permanent dentin.
  
  
  METHODS
  Flat dentin surfaces were produced on sound primary molars and premolars (n = 8). The surfaces were divided into mesial and distal halves, and each half was etched with phosphoric acid for 5 or 15 seconds. The teeth were randomly allocated into two groups according to the adhesive system applied: Prime & Bond NT or Prime & Bond 2.1. After the adhesive application, the specimens were processed for Goldner's trichrome staining. The thickness of the uninfiltrated collagen zone (UCZ) in the hybrid layer was measured under optical microscopy. Data were analyzed by analysis of variance and Tukey tests (α = 0.05).
  
  
  RESULTS
  The thickness of UCZ was adhesive dependent. Within the same substrate, the specimens treated with Prime & Bond 2.1 presented thicker UCZ when etched for 15 seconds. Collagen exposure was significantly higher for the primary teeth etched for 5 seconds and treated with Prime & Bond 2.1.
  
  
  CONCLUSIONS
  The thickness of UCZ in hybrid layers is directly affected by acid-etching time and by the adhesive system applied. Primary dentin seems to be more susceptible to collagen exposure than is permanent dentin.
  
  
  CONCLUSIONS
  Both acid-etching time and adhesive system can influence the amount of exposed collagen interfering on resin-dentin bond quality, especially on primary dentin.
authors: Department of Orthodontics and Pediatric Dentistry Araraquara School of Dentistry, Universidade Estadual Paulista Araraquara, São Paulo, Brazil.
authors: Débora Ls
authors: DL
authors: Scheffel
authors: Department of Restorative Dentistry, Araraquara School of Dentistry, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil.
authors: Cláudia
authors: C
authors: Huck
authors: Department of Physiology and Pathology, Araraquara School of Dentistry, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil.
authors: Diana G
authors: DG
authors: Soares
authors: Department of Physiology and Pathology, Araraquara School of Dentistry, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil.
authors: Fernanda G
authors: FG
authors: Basso
authors: Department of Physiology and Pathology, Araraquara School of Dentistry, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil.
authors: Carlos A
authors: CA
authors: de Souza Costa
authors: Department of Oral Rehabilitation, College of Dental Medicine Augusta University, Augusta, Georgia, USA.
authors: Martha G
authors: MG
authors: Brackett
authors: Department of Oral Biology, College of Dental Medicine Augusta University, Augusta, Georgia, USA.
authors: David H
authors: DH
authors: Pashley
authors: Department of Orthodontics and Pediatric Dentistry Araraquara School of Dentistry, Universidade Estadual Paulista Araraquara, São Paulo, Brazil, Phone: +551633016334, e-mail: jhebling@foar.unesp.br.
authors: Josimeri
authors: J
authors: Hebling
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D001641:Bicuspid / Q000648:ultrastructure; D003094:Collagen / Q000648:ultrastructure*; D001840:Dental Bonding; D019229:Dentition, Permanent; D006801:Humans; D008853:Microscopy; D008963:Molar / Q000648:ultrastructure; D010756:Phosphoric Acids; D013997:Time Factors; D014094:Tooth, Deciduous
chemical_list: D010756:Phosphoric Acids; D003094:Collagen; C030242:phosphoric acid
keywords: Collagen; Degradation; Dentin; Hybrid layer Resin.