Surface contact fatigue and flexural fatigue of dental restorative materials

Abstract

Antagonistic contact on a dental restoration may produce surface and subsurface stresses leading to fatigue wear as well as to bulk stressing, eventually causing catastrophic failure. It was the aim of the present work to study the outcome of two different approaches to fatigue testing of materials involving either surface contact fatigue or flexural fatigue mechanisms. A range of materials was tested, including conventional glass-ionomers, resin-modified glass-ionomers, poly-acid modified composites, and composites. Materials were prepared and tested using both surface contact and flexural fatigue. The results show that conventional glass-ionomers have the least resistance to fatigue under both regimes while composites have the longest fatigue lives and the highest values of flexural fatigue limit. However, the results also support the fact that catastrophic failure should be investigated separately from surface contact fatigue. Within the group of composite products tested, a hybrid composite material had a significantly greater flexural fatigue limit than a microfilled one, but the latter material had a significantly greater surface contact fatigue life, indicating that wear behavior cannot be predicted from bulk fracture characteristics and vice versa. The process of wear occurs by a combination of a number of fundamental processes, and the contribution fatigue makes will vary according to the environment and nature of the material.

Effects of simulated functional loading conditions on dentin, composite, and laminate structures

“…The increase in strength, as with modulus, has been attributed to chain realignment along the extension axis at low extension rates in the amorphous regions of polyethylene46 and crystallization in natural and synthetic rubbers 50. Not surprisingly, just as with the dentin fatigue studies, the results of this study are not supported by previous composite fatigue studies, which report a decreased fatigue life with increasing loading cycles and indirectly, decreased strength 19, 20. However, higher loading rates and stress levels than are associated with mastication were used in those studies.…”

“…5,7 As a result, there is an extensive body of work studying fracture by static/quasistatic loading only. [10][11][12][13] The majority of cyclic loading studies that have been performed on dentin [14][15][16] and composite [17][18][19][20] are traditional fatigue studies using higher stresses and frequencies than are associated with mastication, 21 and thus do not simulate occlusal loading conditions and may not reflect clinical function failure mechanisms.…”

Effect of filler particles on surface roughness of experimental composite series

“…It has been shown that the introduction of finer particles among larger ones will result in reduction of interparticle spacing and the amount of resin matrix, thus maximizing the overall properties of the material 5 . Decreased interparticle spacing caused by reduced filler size may leads to reduction in strain localization around the filler, thus reducing the fatigue failure 9,19 . The concept of multimodal fillers enables the composites to obtain high filler loading and allows a strong integration of small particles into resin matrix that can be eroded by breaking off small individual particles rather than large ones 13,19,20 .…”

In Vitro Exploration and Finite Element Analysis of Failure Mechanisms of Resin‐Bonded Fixed Partial Dentures

“…Furthermore, in the present study, only load to failure has been studied. One should realize that clinically, debonding occurs as a result of fatigue, where fatigue is defined as repeated loading cycles generating lower stresses than the ultimate strength of the material itself 32 …”