applied fracture mechanics

138Applied Fracture Mechanicsmay in fact act as crack stoppers. Take for example a crack that might propagate along acusp toward the central fissure. When that crack reaches the bottom of that fissure, thethickness of the enamel decreases and one can assume that the crack will not continue topropagate up along the other cusp with increasing enamel thickness. In the case of a manmadecrown or filling, the fissure will not serve the same protective purpose. However,because dental students are trained to reproduce the sharp anatomic details, sharp anatomicfissures are often regarded as a sign of good competence, while in reality such details willrather facilitate crack growth.Based on the information provided in this chapter it seems reasonable to suggest that futuredental students should receive more training in fracture mechanics in order to betterunderstand how handling and design may affect the final outcome of a restorativeprocedure Besides, with such a knowledge they would be able to communicate better withother scientists and thereby facilitate the development of better restorative materials.Author detailsKarl-Johan SöderholmCollege of Dentistry, University of Florida, Gainesville, Florida, USA5. References[1] Staines M, Robinson WH, Hood JAA (1981) Spherical Indentation of Tooth Enamel. J.mater. sci. 16:2551-2556.[2] Ten Cate AR. Oral histology : Development, Structure, and Function. 5th ed. St. Louis,Mo.: Mosby; 1998. xi, 497 p.[3] Meckel AH, Griebstein WJ, Neal RJ (1965) Structure of Mature Human Dental Enamelas Observed by Electron Microscopy. Arch. oral biol. 10:775-783. Epub 1965/09/01.[4] Bajaj D, Arola DD (2009) On the R-curve Behavior of Human Tooth Enamel. Biomater.30:4037-4046.[5] Xu HH, Smith DT, Jahanmir S, Romberg E, Kelly JR, Thompson VP, et al. (1998)Indentation Damage and Mechanical Properties of Human Enamel and Dentin. J. dent.res. 77:472-480. Epub 1998/03/13.[6] El Mowafy OM, Watts DC (1986) Fracture Toughness of Human Dentin. J. dent. res.65:677-681. Epub 1986/05/01.[7] Arola D, Huang MP, Sultan MB (1999) The Failure of Amalgam Dental Restorations dueto Cyclic Fatigue Crack Growth. J. mater. sci.-mater. med. 10:319-327.[8] He LH, Swain MV (2008) Understanding the Mechanical Behaviour of Human Enamelfrom its Structural and Compositional Characteristics. J. mech. behav. biomed. mater.1:18-29. Epub 2008/01/01.[9] Lucas P, Constantino P, Wood B, Lawn B (2008) Dental Enamel as a Dietary Indicator inMammals. Bioessays. 30:374-385.[10] Constantino PJ, Lucas PW, Lee JJW, Lawn BR (2009) The Influence of Fallback Foods onGreat Ape Tooth Enamel. Amer. j. phys. anthrop. 140:653-660.