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Journal of dental research, 2009-03, Vol.88 (3), p.224-228
Ort / Verlag
United States: SAGE Publications
Erscheinungsjahr
2009
Quelle
MEDLINE
Beschreibungen/Notizen
The structural integrity of teeth under stress is vital to functional longevity. We
tested the hypothesis that this integrity is limited by fracture of the enamel.
Experiments were conducted on molar teeth, with a metal rod loaded onto individual
cusps. Fracture during testing was tracked with a video camera. Two longitudinal
modes of cracking were observed: median cracking from the contact zone, and margin
cracking along side walls. Median cracks initiated from plastic damage at the contact
site, at first growing slowly and then accelerating to the tooth margin. Margin
cracks appeared to originate from the cemento-enamel junction, and traversed the
tooth wall adjacent to the loaded cusp from the gingival to the occlusal surface. All
cracks remained confined within the enamel shell up to about 550 N. At higher loads,
additional crack modes—such as enamel chipping and delamination—began to manifest
themselves, leading to more comprehensive failure of the tooth structure.