The effect of thermocycling on the determination of microleakage in Permite amalgam restorations.
BACKGROUND
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.


OBJECTIVE
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 - 55 degrees C; 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.


RESULTS
While microleakage at cementum margins was significantly and negatively influenced by thermocycling, enamel margins appeared to be significantly unaffected.


CONCLUSIONS
The effect of thermocycling on the determination of microleakage was only significant at the cementum margins of Permite restorations.
Rajbaran
S
S
Department of Odontology, University of Pretoria, P.O Box 1266, Pretoria, Gauteng, South Africa 0001. sandeepa.rajbaran@up.ac.za
Dannheimer
M
M
De Wet
F
F
D004396:Coloring Agents; D003300:Copper / Q000737:chemistry*; D003723:Dental Amalgam / Q000737:chemistry*; D003736:Dental Cavity Lining / Q000379:methods; D003737:Dental Cavity Preparation / Q000145:classification; D003739:Dental Cementum / Q000473:pathology; D003743:Dental Enamel / Q000473:pathology; D003763:Dental Leakage / Q000145:classification*; D003793:Dental Restoration, Permanent / Q000145:classification*; D006801:Humans; D008422:Materials Testing; D009930:Organic Chemicals / Q000737:chemistry; D016613:Plastic Embedding; D012394:Rosaniline Dyes; D012834:Silver / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D019237:Tooth Cervix / Q000473:pathology
D004396:Coloring Agents; D009930:Organic Chemicals; D012394:Rosaniline Dyes; D012834:Silver; C025485:basic fuchsin; C103328:Polyvar; D003300:Copper; D003723:Dental Amalgam; C092423:Permite C