The effect of thermocycling on the determination of microleakage
in Permite amalgam restorations
Microleakage is an important clinical performance parameter of
restorative materials. A literature review of the effect of thermocycling
on microleakage revealed an incongruity of results.
AIMS AND OBJECTIVES:
The aim of this study was to describe the effect of thermocycling
on microleakage in Class V Permite amalgam restorations.
Methods: Class V cavities were prepared at the mesial and distal
cemento-enamel junctions of 20 extracted, sound, human molar
teeth. Cavities were treated with Polyvar cavity varnish and
restored with Permite amalgam as per manufacturer’s directions.
Teeth were randomly divided into two groups of 10 teeth each.
After one day only one group was thermocycled for 500 hundred
cycles (5 - 55oC; dwell time of 30 seconds: transfer time of 10
seconds). Teeth were subsequently submersed in 0.5% Basic
Fuchsin solution (24 hours: room temperature), then cleaned
and embedded in polyester potting resin. Teeth were sectioned
longitudinally along the long axis of the tooth into three slices
using the Isomet low speed saw. Microleakage was scored under
a light microscope at 10 times magnification.
While microleakage at cementum margins was significantly and
negatively influenced by thermocycling, enamel margins appeared
to be significantly unaffected.
The effect of thermocycling on the determination of microleakage was
only significant at the cementum margins of Permite restorations.