title: Influence of curing methods and materials on the marginal seal of class V composite restorations in vitro.
abstract: The study tests the hypothesis that soft-start irradiation improves, whereas, high intensity irradiation compromises the margin quality and marginal seal of Class V resin based composite [RBC] restorations. Box-shaped Class V cavities were prepared in extracted, human third molars with cervical margins located apical to the CEJ. Cavities were restored using a multi-step bonding agent (Optibond FL, Kerr), a thin layer of flowable resin composite and two increments of fine hybrid resin composite (Filtek Flow/Filtek Z250, 3M ESPE; Revolution f2/Herculite XRV, Kerr). Light irradiation was performed using either the standard (40 seconds) or the soft-start mode (40 seconds with exponential increase) of a quartz tungsten halogen or an LED curing light (Elipar Trilight, Elipar Freelight, 3M ESPE); for high intensity irradiation, a Plasma Are curing unit was used with three irradiations of three seconds (Apollo 95E, DMDS). After 30 days of water storage and thermal cycling (n = 2500, 5-55 degrees C), margin quality was assessed in the SEM using the replica technique and marginal seal was evaluated using dye penetration (AgNO3 50%). Few differences were observed between the light curing protocols. However, less leakage was observed in the case of the lower shrinking RBC Filtek Z250.
authors.affiliation: Department of Operative Dentistry and Periodontology, Julius-Maximilians-University of Wuerzburg, Germany. Norbert.Hofmann@mail.uni-wuerzburg.de
authors.forename: Norbert
authors.initials: N
authors.lastname: Hofmann
authors.forename: Christian
authors.initials: C
authors.lastname: Siebrecht
authors.forename: Burkhard
authors.initials: B
authors.lastname: Hugo
authors.forename: Bernd
authors.initials: B
authors.lastname: Klaiber
mesh_terms: D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D001840:Dental Bonding / Q000379:methods*; D003737:Dental Cavity Preparation / Q000145:classification; D003763:Dental Leakage / Q000145:classification; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000145:classification*; D006801:Humans; D008027:Light; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third / Q000473:pathology; D016628:Replica Techniques; D019279:Resin Cements / Q000737:chemistry; D016622:Silver Staining; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013816:Thermodynamics; D013997:Time Factors; D019237:Tooth Cervix / Q000473:pathology; D014867:Water / Q000737:chemistry
chemical_list: D003188:Composite Resins; C467913:Filtek Flow; C444701:Filtek Z250; C469607:OptiBond FL; D019279:Resin Cements; C102735:Revolution (composite resin); D014867:Water; C065770:Herculite XR