Effect of thermocycling on the microleakage of conventional and resin-modified glass ionomers.
OBJECTIVE
To compare the effect of thermocycling on the microleakage of conventional and resin modified glass ionomer restorative materials.


METHODS
Class V preparations, centered on the CEJ, were prepared on the lingual and facial surfaces of 30 extracted human third molar teeth. Preparations were conditioned and restored randomly on one surface with Ketac-Fil and on the other surface with Photac-Fil. Restorations were protected during curing, finishing, and storage with Ketac-Glaze. Specimens were aged in room temperature distilled water for 7 days. Half of the specimens were thermocycled for 2,500 cycles in 5 degrees-55 degrees water baths with 5-second dwell times. All specimen apices were sealed with red compound, occlusal fissures sealed with pit/fissure sealant, and surfaces painted to within 1.5 mm of restoration margins with red nail polish. Specimens were stained with 5% methylene blue, invested in orthodontic resin, and sectioned faciolingually. The percentage of dye penetration along the tooth restoration interface was measured with a digital imaging system.


RESULTS
Statistical analysis showed that neither thermocycling or type of material had a significant effect on dye penetration (P > 0.5).
Doerr
C L
CL
Department of General Dentistry, Wilford Hall Medical Center, Lackland Air Force Base, Texas, USA.
Hilton
T J
TJ
Hermesch
C B
CB
D000704:Analysis of Variance; D003763:Dental Leakage; D018772:Dental Marginal Adaptation; D018865:Dental Research / Q000379:methods; D005899:Glass Ionomer Cements / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D008298:Maleates; D008422:Materials Testing / Q000379:methods; D019279:Resin Cements; D012117:Resins, Synthetic; D013048:Specimen Handling; D014867:Water / Q000737:chemistry
D005899:Glass Ionomer Cements; D008298:Maleates; C081144:Photac-Fil; D019279:Resin Cements; D012117:Resins, Synthetic; D014867:Water; C040964:Ketac-Fil