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Loss of hard tissue at dental cervical lesions is a puzzling
condition and the restoration of such cervical lesion often
failed owing to leakage and debonding commonly encountered in
clinical practice. In 1991 Grippo first referred to stress-
induced cervical lesion as " abfraction" which is defined as the
pathologic loss of hard tooth substance caused by tensile
stress. However, stress state about dental cervical lesion is
largely unknown. The purpose of this study was focused
on the stress analysis of cervical lesions during masticatory
load by using finite element analysis (FEA) and experimental
strain measurement.
Loads were applied vertically on the lingual cusp, central fossa
and buccal cusp of the upper second premolar in FEA, then stress
in both the buccal and lingual side of the cervical area were
recorded respectively. At that time, we also record stress at a
point other than the cervical area, which was then compared.
The results indicated that the tensile stress generated by
occlusal loads indeed concentrated on cervical area of buccal
side while compressive stress on lingual side. We found that the
large gap between two stresses coincided with the fatigue
theory. And fatigue failure caused abfraction formation on the
side of the tensile stress.
Even considering that the standard deviation between two
approaches in buccal surface is lower than 10%, but higher in
cervical area, this result is still reliable.
We concluded that occlusal loads must be located and directed
more on the central fossa which should then reduce the
destruction of the cervical lesion.
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