title: Marginal and internal analysis of preheated dental fissure-sealing materials using optical coherence tomography.
abstract: OBJECTIVE
  This study aimed to evaluate the influence of pre-photoactivation temperature on the marginal and internal integrity (occurrence of voids) of fissure-sealing materials on occlusal fissures using optical coherence tomography (OCT).
  
  
  METHODS
  Occlusal fissures of 40 human third molars were sealed using a resin-based fissure sealant (Fluroshield) and a flowable composite (Permaflo) photoactivated at 68 °C (preheated) or at room temperature (25 °C) (n=10). After sealing, the teeth were subjected to thermocycling (500 cycles, 5-55 °C) and 14 days of pH cycling (demineralisation for 6 hours/day and remineralisation for 18 hours/day). The occlusal surfaces were scanned in a buccolingual direction, and 20 tomographic images parallel to the long axis of each tooth were obtained. Images presenting marginal gaps and internal voids were counted and statistically analysed using analysis of variance and Tukey's test (P<0.05).
  
  
  RESULTS
  There were statistically significant differences between materials and temperatures (P<0.01). The flowable composite had a lower percentage of gaps and internal voids than the resin-based sealant. Preheated materials had a lower percentage of gaps and internal voids than the materials at room temperature.
  
  
  CONCLUSIONS
  Therefore, preheated flowable composite provided the best marginal sealing of fissures, and internal homogeneity of the material.
authors.affiliation: Department of Dentistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Boniek Castillo Dutra
authors.initials: BC
authors.lastname: Borges
authors.affiliation: Department of Dentistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Isauremi Vieira
authors.initials: IV
authors.lastname: de Assunção
authors.affiliation: Department of Dentistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Célia Avani
authors.initials: CA
authors.lastname: de Aquino
authors.affiliation: Dental School, University of Pernambuco, Camaragibe, PE, Brazil.
authors.forename: Gabriela Queiroz
authors.initials: GQ
authors.lastname: de Melo Monteiro
authors.affiliation: Department of Physics, Universidade Federal de Pernambuco, Recife, PE, Brazil.
authors.forename: Anderson Stevens Leonidas
authors.initials: AS
authors.lastname: Gomes
mesh_terms: D003763:Dental Leakage; D018772:Dental Marginal Adaptation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D010895:Pit and Fissure Sealants / Q000737:chemistry*; D013696:Temperature; D041623:Tomography, Optical Coherence
chemical_list: D010895:Pit and Fissure Sealants
keywords: Pit-and-fissure sealant; flowable composite; internal voids; marginal adaptation; optical coherence tomography