aim of this research is to clarify whether the midline axis of the complete upper
denture (CUD) is the axis of its torsion during loading, apart from the known bending
deflection. Furthermore the present study is intended to estimate the influence
of the anterior notches on the torsional deformation of the CUD. Using commercial
edentulous molds and standardized procedures, six identical CUDs were fabricated
with an initial fraenal notch of 5 mm. Two additional notch conditions were produced
by deepening the notch to a total depth of 9 mm and by creating an incisal diastema
of 7 mm. Five biaxial (also known as “fish bone”) strain gauges were cemented onto
the palatal section of the dentures so that their middle axis coincided with the
midline axis of the outer surface of the denture. For the denture specimen used
in this study, the specific point of torsion was detected 2 cm from the point of
contact of the two artificial central incisors. The presence of a deep fraenal
notch and the combination of the deep fraenal notch with the presence of an incisal
diastema increased the torsion of the CUD to a significant level (P = 0.006 and P = 0.05, respectively). It was shown that the midline can be the CUD’s
axis of torsion. Biaxial strain gauges could be a reliable method of measuring the
torsional deformation of the CUD.
Cite this paper
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