title: Marginal analysis of resin composite restorative systems using optical coherence tomography.
abstract: OBJECTIVE
  To analyze marginal integrity of resin composites dental restorations using optical coherence tomography (OCT).
  
  
  METHODS
  Thirty extracted human premolars had occlusal cavities prepared and were randomly divided according to the restorative systems evaluated: Filtek P90™/P90 Adhesive System™, Filtek Z350™, and Filtek Z250™/Single Bond™ (3M/ESPE). The teeth were then stored in the dark for 24h in 0.9% saline solution. Restorations were finished and polished and stored again for 24h before thermocycling (500 cycles, 5-55°C). A commercially available OCT system was used (SR-OCT: OCP930SR/Thorlabs) with 930nm central wavelength. Cross-sectional images were obtained every 250μm and evaluated using Image J. A-scans were analyzed using the Origin 8.0 program, after a filter treatment using Matlab.
  
  
  RESULTS
  The qualitative analysis of the internal margins did not observe gaps even after A-scan examination, although distinctive patterns were found for each restorative system. Penetration of Single Bond and Filtek P90 self-etch primer into dentin was also observed. A thick adhesive layer was found for Filtek P90 bonding agent.
  
  
  CONCLUSIONS
  Considering the characteristics of the OCT system, the setup used in this study was capable of evaluating the marginal integrity of resin composite restorations and detecting some interaction between dental bonding agents and dental substrates. OCT can be considered a promising method for the evaluation of the internal margins of restorations in vivo.
authors.affiliation: Department of Restorative Dentistry, Universidade de Pernambuco-FOP/UPE, Camaragibe, PE, Brazil. gabrielaqueiroz@hotmail.com.br
authors.forename: Gabriela Q M
authors.initials: GQ
authors.lastname: Monteiro
authors.forename: Marcos A J R
authors.initials: MA
authors.lastname: Montes
authors.forename: Anderson S L
authors.initials: AS
authors.lastname: Gomes
authors.forename: Claudia C B O
authors.initials: CC
authors.lastname: Mota
authors.forename: Sérgio L
authors.initials: SL
authors.lastname: Campello
authors.forename: Anderson Z
authors.initials: AZ
authors.lastname: Freitas
mesh_terms: D001641:Bicuspid / Q000473:pathology; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D003624:Darkness; D003737:Dental Cavity Preparation / Q000379:methods; D003738:Dental Cements / Q000737:chemistry; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing; D003793:Dental Restoration, Permanent / Q000379:methods*; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008422:Materials Testing; D055116:Self-Curing of Dental Resins; D012965:Sodium Chloride / Q000737:chemistry; D013696:Temperature; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000295:instrumentation / Q000379:methods*
chemical_list: C554641:Adper single bond 2; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; C544925:filtek P90; C533204:filtek Z350; D012965:Sodium Chloride