Journal of Dentistry
Volume 37, Issue 10 , Pages 799-806, October 2009

Edge strength of indirect restorative materials

  • Nadia Ereifej

      Affiliations

    • Department of Prosthodontics, School of Dentistry, The University of Jordan, Amman, Jordan
    • Biomaterials Science Research Group, School of Dentistry, The University of Manchester, UK
    • Corresponding Author InformationCorresponding author at: Department of Prosthodontics, School of Dentistry, The University of Jordan, Amman 11942, Jordan. Tel.: +962 797379525.
    • ,
  • Nick Silikas

      Affiliations

    • Biomaterials Science Research Group, School of Dentistry, The University of Manchester, UK
    • Photon Science Institute, The University of Manchester, UK
    • ,
  • David C. Watts

      Affiliations

    • Biomaterials Science Research Group, School of Dentistry, The University of Manchester, UK
    • Photon Science Institute, The University of Manchester, UK

Received 8 April 2009; accepted 12 June 2009. published online 22 June 2009.

Abstract 

Objectives

To evaluate the edge strength and fracture patterns of different all-ceramic and indirect composite materials used in prosthodontic applications.

Methods

Fourteen rectangular-shaped samples (2–2.5mm thick) were prepared of each of the following materials: BelleGlass NG (Kerr) (BG), fibre-reinforced BelleGlass/EverStick (Kerr/Stick Tech Ltd.) (BGES), Vita Mark II (Vita Zahnfabrik) (VMII), bilayered IPS e.max Ceram/CAD (Ivoclar-Vivadent) (Ceram/CAD), bilayered IPS e.max Ceram/ZirCAD (Ivoclar-Vivadent) (Ceram/ZirCAD) and unilayered IPS e.max CADLT (Ivoclar-Vivadent) (CADLT). Each group was further subdivided into seven subgroups (n=2) corresponding to different edge distances at which samples were loaded. Samples were tested with an edge strength machine (CK10, Engineering Systems, Nottingham, UK) using a diamond Vickers indenter. The force-to-failure (N) was recorded and four readings were obtained per sample. The mode of failure was analysed microscopically. One-way ANOVA was used to detect differences in edge strength among the groups and correlation and regression analyses were used to detect the correlation between distance of loading and failure force.

Results

The mean values of edge strength (N) were 94.1 (11.2) for BG, 134.4 (10.9) for BGES, 50.5 (8.9) for VMII, 54.4 (7.5) for Ceram/CAD, 53.2 (8.4) for Ceram/ZirCAD and 69.1 (9.1) for CADLT. Significant (p<0.05) strong positive linear correlations were found between the force-to-failure and edge distance among all groups. Three patterns of failure were identified: surface indentation without visible cracking, surface indentation with visible cracking and chipping.

Conclusions

Indirect composite materials had better edge fracture behaviour than all-ceramic materials. The addition of fibres enhanced the performance of the resin-composite material. Fracture strength increased as the distance from the edge increased. Edge fracture was restricted to the veneer material in bilayared systems and therefore a stronger veneer material is recommended.

Keywords: Edge strength, All-ceramic, Fibre-reinforced composite, Fractography, IPS e.max, Crack, Acoustic emission

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PII: S0300-5712(09)00153-5

doi:10.1016/j.jdent.2009.06.009

Journal of Dentistry
Volume 37, Issue 10 , Pages 799-806, October 2009

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