Fracture Surface Analysis of Clinically Failed Fixed Partial Dentures
B. Taskonak1,*,
J.J. Mecholsky, Jr.2, and
K.J. Anusavice3
1 Department of Restorative Dentistry, Division of Dental Biomaterials, Indiana University, School of Dentistry, 1121 W. Michigan St., Indianapolis, IN 46202, USA;
2 Department of Materials Science and Engineering, College of Engineering, University of Florida; and
3 Department of Dental Biomaterials, College of Dentistry, University of Florida
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Figure 1. Schematic of a fixed partial denture with fracture initiation sites and numbers.
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Figure 2. Fracture origin can be identified by fracture markings. (a) All fracture surfaces exhibit multiple crack initiation sites as a result of multidirectional loading. Arrest lines in the form of ridges are present on the fracture surfaces. One of the arrest lines is a result of intersection of 2 fracture paths. Arrows represent the fracture propagation direction. (b) Wake hackle markings were used to establish the reference points for determining the fracture origin in the glass veneer. Wake hackle markings were also observed on porosities as an outcome of fracture passage through pores. The markings indicate the direction of the fracture origin in the veneer layer. Black arrows specify the direction of the fracture propagation. (c) Fracture toughness of the glass veneer was used to calculate the stress at failure of samples in which the fracture origin was within the veneer layer. Fracture propagates quickly without any increase in stress from the point where the semi-minor axis of the fracture origin ends. Arrows represent the interface between core and veneer layers, as well as fracture origin.
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