Effect of thermocycling on bond strength and elasticity of 4 long-term soft denture liners

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dc.contributor.authorPinto, J R R
dc.contributor.authorMesquita, M. F.
dc.contributor.authorHenriques, G E P
dc.contributor.authorNobilo, M A D
dc.contributor.institutionUniversidade Estadual de Campinas (UNICAMP)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-20T15:21:29Z
dc.date.available2014-05-20T15:21:29Z
dc.date.issued2002-11-01
dc.description.abstractStatement of problem. Two problems found in prostheses with soft liners are bond failure to the acrylic resin base and loss of elasticity due to material aging.Purpose. This in vitro study evaluated the effect of thermocycling on the bond strength and elasticity of 4 long-term soft denture liners to acrylic resin bases.Material and methods. Four soft lining materials (Molloplast-B, Flexor, Permasoft, and Pro Tech) and 2 acrylic resins (Classico, and Lucitone 199) were processed for testing according to manufacturers' instructions. Twenty rectangular specimens (10 X 10-mm(2) cross-sectional area) and twenty cylinder specimens (12.7-mm diameter X 19.0-mm height) for each liner/resin combination were used for the tensile and deformation tests, respectively. Specimen shape and liner thickness were standardized. Samples were divided into a test group that was thermocycled 3000 times and a control group that was stored for 24 hours in water at 37degreesC. Mean bond strength, expressed in megapascals (Wa), was determined in the tensile test with the use of a universal testing machine at a crosshead speed of 5 mm/min. Elasticity, expressed as percent of permanent deformation, was calculated with an instrument for measuring permanent deformation described in ADA/ANSI specification 18. Data from both tests were examined with 1-way analysis of variance and a Tukey test, with calculation of a Scheffe interval at a 95% confidence level.Results. In the tensile test under control conditions, Molloplast-B (1.51 +/- 0.28 MPa [mean SD]) and Pro Tech (1.44 +/- 0.27 MPa) liners had higher bond strength values than the others (P < .05). With regard to the permanent deformation test, the lowest values were observed for Molloplast-B (0.48% +/- 0.19%) and Flexor (0.44% +/- 0.14%) (P < .05). Under thermocycling conditions, the highest bond strength occurred with Molloplast-B (1.37 +/- 0.24 MPa) (P < .05) With regard to the deformation test, Flexor (0.46% +/- 0.13%) and Molloplast-B (0.44% +/- 0.17%) liners had lower deformation values than the others (P < .05).Conclusion. The results of this in vitro study indicated that bond strength and permanent deformity values of the 4 soft denture liners tested varied according to their chemical composition. These tests are not completely valid for application to dental restorations because the forces they encounter are more closely related to shear and tear. However, the above protocol serves as a good method of investigation to evaluate differences between thermocycled and control groups.en
dc.description.affiliationUNICAMP, FOP, Dept Protese & Periodontia, Sch Dent, BR-13414018 São Paulo, Brazil
dc.description.affiliationUniv Estadual Paulista, Sch Dent, BR-01405 São Paulo, Brazil
dc.description.affiliationUnespUniv Estadual Paulista, Sch Dent, BR-01405 São Paulo, Brazil
dc.format.extent516-521
dc.identifierhttp://dx.doi.org/10.1067/mpr.2002.128953
dc.identifier.citationJournal of Prosthetic Dentistry. St Louis: Mosby, Inc., v. 88, n. 5, p. 516-521, 2002.
dc.identifier.doi10.1067/mpr.2002.128953
dc.identifier.issn0022-3913
dc.identifier.urihttp://hdl.handle.net/11449/32613
dc.identifier.wosWOS:000180008800010
dc.language.isoeng
dc.publisherMosby, Inc
dc.relation.ispartofJournal of Prosthetic Dentistry
dc.relation.ispartofjcr2.347
dc.relation.ispartofsjr1,087
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.titleEffect of thermocycling on bond strength and elasticity of 4 long-term soft denture linersen
dc.typeArtigo
dcterms.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dcterms.rightsHolderMosby, Inc
unesp.author.orcid0000-0003-1967-6628[2]

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