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Initial versus final fracture of metal-free crowns, analyzed via acoustic emission.
Dent Mater. 2008 Sep; 24(9):1289-95.DM

Abstract

OBJECTIVE

To discriminate between initial and final fracture failure loads of four metal-free crown systems by the conjoint detection of acoustic emission signals during compressive loading.

METHODS

Teeth were prepared and used for crown construction with four crown systems; Vita Mark II (VM II) (Vita Zahnfabrik), IPS e.max Ceram/CAD (CAD) (Ivoclar-Vivadent), IPS e.max Ceram/ZirCAD (ZirCAD) (Ivoclar-Vivadent) and BelleGlass/EverStick (BGES) (Kerr/Stick Tech Ltd.). All samples were loaded in compression via a Co/Cr maxillary first molar tooth at 0.2mm/min and released acoustic signals were collected and analyzed. A minimum number of 15 crowns per group were loaded to final failure and values of loading at initial and final fracture were compared. Additional four samples per group were loaded till fracture initiation and were fractographically examined under the optical microscope.

RESULTS

A lower threshold of 50dB was selected to exclude spurious background signals. Initial fracture forces were significantly lower than those of final fracture (p<0.05) in all groups and initial failure AE amplitudes were lower than those of final fracture. Mean initial fracture force of ZirCAD samples (1029.1N) was higher than those of VMII (744.4N), CAD (808.8 N) and BGES (979.7 N). Final fracture of ZirCAD also occurred at significantly higher force values (2091.7 N) than the rest of the groups; VMII (1120.9 N), CAD (1468.9 N) and BGES (1576.6 N). Significantly higher values of initial failure AE amplitude were found in VMII than CAD and BGES while those of final fracture were similar. All crowns observed under the microscope at initial fracture had signs of failure.

SIGNIFICANCE

Whereas the metal-free crowns examined showed significant variations in final failure loads, acoustic emission data showed that they all manifested initial failures at significantly lower load values.

Authors+Show Affiliations

Biomaterials Science Research Group, School of Dentistry, The University of Manchester, UK.No affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

18573522

Citation

Ereifej, Nadia, et al. "Initial Versus Final Fracture of Metal-free Crowns, Analyzed Via Acoustic Emission." Dental Materials : Official Publication of the Academy of Dental Materials, vol. 24, no. 9, 2008, pp. 1289-95.
Ereifej N, Silikas N, Watts DC. Initial versus final fracture of metal-free crowns, analyzed via acoustic emission. Dent Mater. 2008;24(9):1289-95.
Ereifej, N., Silikas, N., & Watts, D. C. (2008). Initial versus final fracture of metal-free crowns, analyzed via acoustic emission. Dental Materials : Official Publication of the Academy of Dental Materials, 24(9), 1289-95. https://doi.org/10.1016/j.dental.2008.04.010
Ereifej N, Silikas N, Watts DC. Initial Versus Final Fracture of Metal-free Crowns, Analyzed Via Acoustic Emission. Dent Mater. 2008;24(9):1289-95. PubMed PMID: 18573522.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Initial versus final fracture of metal-free crowns, analyzed via acoustic emission. AU - Ereifej,Nadia, AU - Silikas,Nick, AU - Watts,David C, Y1 - 2008/06/24/ PY - 2008/01/22/received PY - 2008/03/06/revised PY - 2008/04/22/accepted PY - 2008/6/25/pubmed PY - 2008/12/17/medline PY - 2008/6/25/entrez SP - 1289 EP - 95 JF - Dental materials : official publication of the Academy of Dental Materials JO - Dent Mater VL - 24 IS - 9 N2 - OBJECTIVE: To discriminate between initial and final fracture failure loads of four metal-free crown systems by the conjoint detection of acoustic emission signals during compressive loading. METHODS: Teeth were prepared and used for crown construction with four crown systems; Vita Mark II (VM II) (Vita Zahnfabrik), IPS e.max Ceram/CAD (CAD) (Ivoclar-Vivadent), IPS e.max Ceram/ZirCAD (ZirCAD) (Ivoclar-Vivadent) and BelleGlass/EverStick (BGES) (Kerr/Stick Tech Ltd.). All samples were loaded in compression via a Co/Cr maxillary first molar tooth at 0.2mm/min and released acoustic signals were collected and analyzed. A minimum number of 15 crowns per group were loaded to final failure and values of loading at initial and final fracture were compared. Additional four samples per group were loaded till fracture initiation and were fractographically examined under the optical microscope. RESULTS: A lower threshold of 50dB was selected to exclude spurious background signals. Initial fracture forces were significantly lower than those of final fracture (p<0.05) in all groups and initial failure AE amplitudes were lower than those of final fracture. Mean initial fracture force of ZirCAD samples (1029.1N) was higher than those of VMII (744.4N), CAD (808.8 N) and BGES (979.7 N). Final fracture of ZirCAD also occurred at significantly higher force values (2091.7 N) than the rest of the groups; VMII (1120.9 N), CAD (1468.9 N) and BGES (1576.6 N). Significantly higher values of initial failure AE amplitude were found in VMII than CAD and BGES while those of final fracture were similar. All crowns observed under the microscope at initial fracture had signs of failure. SIGNIFICANCE: Whereas the metal-free crowns examined showed significant variations in final failure loads, acoustic emission data showed that they all manifested initial failures at significantly lower load values. SN - 0109-5641 UR - https://www.unboundmedicine.com/medline/citation/18573522/Initial_versus_final_fracture_of_metal_free_crowns_analyzed_via_acoustic_emission_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0109-5641(08)00140-1 DB - PRIME DP - Unbound Medicine ER -