Effect of a ferrule and increased clinical crown length on the In Vitro fracture resistance of premolars restored using two dowel-and-core systems

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dc.contributor.authorMeng, Q.
dc.contributor.authorChen, Y.
dc.contributor.authorGuang, H.
dc.contributor.authorYip, K.
dc.contributor.authorSmales, R.
dc.date.issued2007
dc.description.abstractThis study investigated the effect of a crown-lengthening ferrule on the fracture resistance of endodontically-treated teeth restored with two dowel-core systems. Thirty-two extracted mandibular first premolars were sectioned perpendicular to the long axis at a point 1.0 mm occlusal to the buccal cementoenamel junction. Following endodontic treatment, the teeth were randomly assigned to four groups: cast Ni-Cr alloy dowel-core with no ferrule (Group A1), cast Ni-Cr alloy dowel-core with 2.0 mm ferrule (Group A2), prefabricated carbon fiber-reinforced dowel-resin core with no ferrule (Group B1) and carbon fiber-reinforced dowel-resin core with 2.0 mm ferrule (Group B2). Each specimen was embedded in a self-cured acrylic resin block from 2.0 mm apical to the margins of a cast Ni-Cr alloy crown, then loaded at 150 degrees from the long axis in a universal testing machine at a crosshead speed of 1.0 mm/minute until fracture. The data were recorded and analyzed using ANOVA and Fisher's exact tests, with alpha = 0.05. Mean failure loads (kN) for the A1, A2, B1 and B2 Groups were: 1.46 (S.D. 0.45), 1.07 (0.21), 1.13 (0.30) and 1.02 (0.27). The teeth restored with cast Ni-Cr dowel-cores and 2.0 mm ferrules demonstrated significantly lower fracture strengths, p = 0.04. There were significant differences in the root fracture patterns between the two dowel systems, with the carbon fiber-reinforced dowel-resin core system, being the less severe p < 0.05. Crown lengthening with a 2.0 mm apical extended ferrule resulted in reduced fracture strengths for endodontically-treated teeth restored using two dowel-core systems and cast metal crowns. The carbon fiber-reinforced dowel-resin core system reduced the severity of the root fractures.
dc.description.urihttp://www.jopdent.org/journal/articles/files/Volume_32__2007.php#num6
dc.identifier.citationOperative Dentistry, 2007; 32(6):595-601
dc.identifier.doi10.2341/06-169
dc.identifier.issn0361-7734
dc.identifier.issn1559-2863
dc.identifier.urihttp://hdl.handle.net/2440/44407
dc.language.isoen
dc.publisherOperative Dentistry Inc
dc.source.urihttps://doi.org/10.2341/06-169
dc.subjectBicuspid
dc.subjectHumans
dc.subjectTooth, Nonvital
dc.subjectTooth Fractures
dc.subjectAnalysis of Variance
dc.subjectCrown Lengthening
dc.subjectPost and Core Technique
dc.subjectTooth Preparation
dc.subjectAdult
dc.titleEffect of a ferrule and increased clinical crown length on the In Vitro fracture resistance of premolars restored using two dowel-and-core systems
dc.typeJournal article
pubs.publication-statusPublished

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