The effect of a fiber reinforced cavity configuration on load bearing capacity and failure mode of endodontically treated molars restored with CAD/CAM resin composite overlay restorations. Issue 9 (September 2015)

• Record Type: Journal Article
• Authors: Rocca, G.T.; Saratti, C.M.; Cattani-Lorente, M.; Feilzer, A.J.; Scherrer, S.; Krejci, I.
• Is Part Of: Journal of dentistry. Volume 43:Issue 9(2015:Sep.)
• Page Start: 1106
• Page End: 1115
• Publication Date: 2015-09
• Subjects: Dentistry -- Periodicals; Dentistry -- Periodicals; Dentisterie -- Périodiques; Electronic journals; 617.6005
• DOI: 10.1016/j.jdent.2015.06.012
• Languages: English
• ISSNs: 0300-5712

Abstract

<abstract abstract-type="author" id="abs0005"> <title id="sect0005">Abstract</title> <sec> <title id="sect0010">Objectives</title> <p id="spar0060">To evaluate the fracture strength and the mode of failure of endodontically treated molars restored with CAD/CAM overlays with fiber reinforced composite build-up of the pulp chamber.</p> </sec> <sec> <title id="sect0015">Methods</title> <p id="spar0065">40 Devitalized molars were cut over the CEJ and divided into five groups (<italic>n</italic> = 8). The pulp chamber area was filled with: group 0 (control), no resin build-up; group 1, hybrid composite build-up (G-aenial posterior, GC); group 2, as in group 1 but covered with 3 nets of bi-directional E-glass fibers (EverStickNET, Stick Tech Ltd.); group 3, a FRC resin (EverX posterior, GC); group 4, as in group 3 but covered by the bi-directional fibers. The crowns were restored with CAD–CAM composite restorations (Lava Ultimate, 3M ESPE). Maximum fracture loads were recorded in Newton and data were analyzed using Kruskal–Wallis test (<italic>p</italic> < 0.05). Fragments were analyzed using SEM.</p> </sec> <sec> <title id="sect0020">Results</title> <p id="spar0070">The mean static loads in Newton were: group 0: 2448 (546); group 1: 2817 (873); group 2: 2128 (952); group 3: 2429 (1091); group 4: 2577 (833). No significant differences were found between the groups (<italic>p</italic> > 0.05). All specimens fractured in a catastrophic way, under the CEJ. The main crack evolved in the corono-apical direction. In groups 2 and 4 secondary fracture paths with apico-coronal direction were detected close to the bi-directional fibers' layer.</p> </sec> <sec> <title id="sect0025">Conclusions</title> <p id="spar0075">For the restoration of endodontically treated molars, the incorporation of FRCs did not influence the load-bearing capacity of the tooth–restoration complex. The SEM analysis showed a low ability of the bi-directional fibers net in deviating the fracture but this effect was not sufficient to lead more favorable fracture patterns, over the CEJ.</p> </sec> <sec> <title id="sect0030">Clinical significance</title> <p id="spar0080">The use of FRCs to reinforce the "core" of devitalized molars against vertical fractures under static loads seems useless when the thickness of the CAD/CAM composite overlay restoration is high.</p> </sec> </abstract>