0
Review Article

On the Mechanics of Fatigue and Fracture in Teeth

[+] Author and Article Information
Mobin Yahyazadehfar

Department of Mechanical Engineering,
University of Maryland Baltimore County,
Baltimore, MD 21250

Juliana Ivancik

Department of Mechanical Engineering,
University of Maryland Baltimore County,
Baltimore, MD 21250;
Protective Equipment Division,
U.S Army Aberdeen Test Center,
Aberdeen, MD 21001

Hessam Majd

Department of Mechanical Engineering,
University of Maryland Baltimore County,
Baltimore, MD 21250

Bingbing An

Department of Mechanics,
Shanghai University,
Shanghai 200444, China;
Shanghai Key Laboratory of
Mechanics in Energy Engineering,
Shanghai 200072, China

Dongsheng Zhang

Department of Mechanics,
Shanghai University,
Shanghai 200444, China;
Shanghai Key Laboratory of
Mechanics in Energy Engineering,
Shanghai 200072, China

Dwayne Arola

Department of Materials Science
and Engineering,
University of Washington,
Seattle, WA 98195;
Department of Endodontics,
Prosthodontics, and Operative Dentistry,
Dental School,
University of Maryland,
Baltimore, MD 21201
e-mail: darola@umbc.edu

1Corresponding author.

Manuscript received October 7, 2013; final manuscript received March 30, 2014; published online April 30, 2014. Assoc. Editor: Francois Barthelat.

Appl. Mech. Rev 66(3), 030803 (Apr 30, 2014) (19 pages) Paper No: AMR-13-1081; doi: 10.1115/1.4027431 History: Received October 07, 2013; Revised March 30, 2014

Tooth fracture is a major concern in the field of restorative dentistry. However, knowledge of the causes for tooth fracture has developed from contributions that are largely based within the field of mechanics. The present manuscript presents a technical review of advances in understanding the fracture of teeth and the fatigue and fracture behavior of their hard tissues (i.e., dentin and enamel). The importance of evaluating the fracture resistance of these materials, and the role of applied mechanics in developing this knowledge will be reviewed. In addition, the complex microstructures of tooth tissues, their roles in resisting tooth fracture, and the importance of hydration and aging on the fracture resistance of tooth tissues will be discussed. Studies in this area are essential for increasing the success of current treatments in dentistry, as well as in facilitating the development of novel bio-inspired restorative materials for the future.

Copyright © 2014 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Tooth anatomy. (a) Schematic of human tooth. (reprinted from Ref. [10] with permission from the publisher) (b) micrograph of the dentin's microstructure. T, IT, and PT represent tubule, intertubular, and peritubular dentin, respectively, (c) micrograph of enamel microstructure.

Grahic Jump Location
Fig. 2

Cracks in human teeth. (a) Cracks in unrestored anterior teeth, (b) crack development in tooth restored with amalgam restoration. The crack initiated at the interface of the restoration and tooth structure in the region where there is a large stress concentration (the encircled area). Note that the crack extension is perpendicular to the tubule orientation in dentin.

Grahic Jump Location
Fig. 3

Contact loading failures in human molar teeth. (a) Schematic of various cracks types on tooth surface, (b) crack formation on a human molar due to contact with a flat indenter on the top of the cusp (reprinted from Ref. [38] with permission from the publisher). M and R in the figure stand for margin and radial cracks, respectively (reprinted from Ref. [95] with permission from the publisher). (c) Measured radial crack size as a function of indentation load (reprinted from Ref. [37] with permission from the publisher), (d) measured margin crack size as a function of indentation load (reprinted from Ref. [37] with permission from the publisher). PR and PM are the estimated critical loads from developed contact models.

Grahic Jump Location
Fig. 4

Schematic of various testing configurations used for dental materials. (a) Compact sandwich specimen (reprinted from Ref. [46] with permission from the publisher), (b) NTP specimen (reprinted from Ref. [50] with permission from the publisher), (c) three point bending specimen (reprinted from Ref. [61] with permission from the publisher), (d) four point bending specimen (reprinted from Ref. [61] with permission from the publisher), (e) miniature CT specimen (reprinted from Ref. [64] with permission from the publisher), (f) inset CT specimen (reprinted from Ref. [63] with permission from the publisher).

Grahic Jump Location
Fig. 5

R-curve response of human enamel. (a) Typical R-curve response of enamel for cracks growing from occlusal surface toward the DEJ (reprinted from Ref. [88] with permission from the publisher), (b) comparison of R-curve response of enamel for forward and reverse crack growth directions (reprinted from Ref. [88] with permission from the publisher).

Grahic Jump Location
Fig. 6

The influence of prism decussation on the crack growth resistance of human enamel. (a) A comparison of crack growth resistance of enamel in the transverse and longitudinal directions (reprinted from Ref. [100] with permission from the publisher. (b) characterization of the degree of decussation of enamel from fracture surface (reprinted from Ref. [100] with permission from the publisher). The arrow is indicative of crack growth in the specimen. (c) Crack growth resistance of enamel in the transverse direction as a function of degree of decussation (D) (reprinted from Ref. [100] with permission from the publisher).

Grahic Jump Location
Fig. 7

Crack path within human enamel resulting from incremental crack growth from the notch in the transverse direction. (a) Crack path in outer enamel (reprinted from Ref. [100] with permission from the publisher), (b) crack path in inner enamel (reprinted from Ref. [100] with permission from the publisher) . Note that the crack growth is from left to right.

Grahic Jump Location
Fig. 8

Crack growth response of human coronal dentin obtained from miniaturized CT specimen. (a) Typical R-curve response in dentin (reprinted from Ref. [66] with permission from the publisher), (b) R-curve response for the crack growing perpendicular to the tubules (90 deg orientation) (reprinted from Ref. [120] with permission from the publisher), (c) R-curve response for the crack growing parallel to the tubule plane (0 deg orientation) (reprinted from Ref. [66] with permission from the publisher). (d) A comparison of the crack growth resistance of dentin in 0 deg orientation as a function of spatial distance with respect to occlusal surface (reprinted from Ref. [66] with permission from the publisher). Note that the results presented in both Figs. 8(b) and 8(c) achieved from middle dentin.

Grahic Jump Location
Fig. 9

Toughening mechanisms in human coronal dentin for cracks oriented perpendicular to the tubules. (a) The development of unbroken ligaments in the intertubular dentin (reprinted from Ref. [120] with permission from the publisher). Note that the crack is growing from right to left. (b) Bridging ligaments formed by dentin collagen (reprinted from Ref. [120] with permission from the publisher) (c) microcracks and separation in the peritubular cuffs as shown with the white arrows (reprinted from Ref. [120] with permission from the publisher).

Grahic Jump Location
Fig. 10

Toughening mechanisms during crack growth in human coronal dentin in the direction parallel to the tubules. (a) Crack extension in inner dentin. The crack primarily extends from lumen to lumen as shown with the white arrows. Some degree of peritubular microcracking is also observed at the crack tip as outlined (white encircled area) (reprinted from Ref. [141] with permission from the publisher). (b) Micrograph showing the presence of ligaments bridging the crack in inner dentin (arrows) (reprinted from Ref. [141] with permission from the publisher), (c) microcracking of the peritubular cuffs is predominant in central dentin (reprinted from Ref. [141] with permission from the publisher), (d) example of ligaments bridging the crack and microcracks observed during crack growth in outer dentin (reprinted from Ref. [141] with permission from the publisher).

Grahic Jump Location
Fig. 11

Fatigue life response of human enamel. (a) Schematic of enamel specimen preparation and testing (b) fatigue life response of enamel (reprinted from Ref. [130] with permission from the publisher). Note that the enamel cubes were oriented in specimens in such a manner that the occlusal surface was always subjected to tension (reprinted from Ref. [130] with permission from the publisher). Arrows represent those samples that did not fail within 1.2 × 106 cycles.

Grahic Jump Location
Fig. 12

Fatigue crack growth response of human enamel. (a) Typical fatigue crack growth response in enamel from inset CT specimen (reprinted from Ref. [88] with permission from the publisher), (b) comparison of the fatigue crack growth resistance of enamel for crack extension in the forward and reverse directions (reprinted from Ref. [88] with permission from the publisher).

Grahic Jump Location
Fig. 13

Fatigue life response of human coronal dentin. (a) The role of tubule orientation on the fatigue life response of young coronal dentin (reprinted from Ref. [140] with permission from the publisher), (b) comparison of fatigue life diagram for bur treated dentin beams and control beams (reprinted from Ref. [26] with permission from the publisher) . Arrows indicate those beams that did not fail.

Grahic Jump Location
Fig. 14

Comparison of fatigue crack growth resistance of human coronal dentin at room and human body temperatures

Grahic Jump Location
Fig. 15

Influence of aging on the microstructure and fatigue response of human dentin. (a) Micrographs of fatigue fracture surfaces of young (left) and old (right) dentin (reprinted from Ref. [141] with permission from the publisher). Note that the tubules in young dentin are open. However, they become occluded with aging. (b) Comparison of the fatigue life responses of old and young dentin (reprinted from Ref. [61] with permission from the publisher) (c) comparison of fatigue crack growth responses of old and young dentin (reprinted from Ref. [141] with permission from the publisher).

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In