Microleakage of different amalgams bonded with dual cure resin cements.
BACKGROUND
To reduce microleakage in high-copper amalgam restorations, bonding of amalgam was introduced.


OBJECTIVE
This study compared the microleakage of admixed and spherical amalgams when bonded with different bonding intermediates under thermo- and non-thermocycling conditions.


METHODS
Class II butt-joint cavities were prepared in 200 extracted human molar teeth, and randomly divided into 5 groups. Calibra, Duo Cement Plus, RelyX ARC and Amalgambond Plus were applied to 4 of these groups. The fifth group was left untreated. The groups were further divided and restored with either Dispersalloy or Oralloy Magicap S. Ten specimens of each group were thermocycled between 5 degrees C and 55 degrees C, placed in basic fuchsin for 8 hours, sectioned and evaluated for dye penetration under 40X magnification. The mean microleakage scores were analysed using the chi-squared test at a confidence level of 95%.


RESULTS
Microleakage of the non-bonded amalgams was significantly higher (p < 0.0001) than for the bonded amalgams (thermocycled and non-thermocycled). The microleakage of the different intermediates bonded to Dispersalloy (thermocycled and non-thermocycled) was not significantly different (p > 0.05). The microleakage of the different intermediates was not significant different except for Duo Cement compared to Calibra (p < 0.0001), RelyX (p < 0.0001) and Amalgambond (p = 0.0433) and Amalgambond compared to Calibra (p = 0.0433) and RelyX (p = 0.0433). The microleakage of the bonded amalgams was not significantly increased by thermocycling (p > 0.05). The microleakage of the two amalgams when bonded with the same resin cements (thermocycled and non-thermocycled) was not significantly different except for Duo Cement (thermocycled) (p = 0.0051) and RelyX (non-thermocycled) (p = 0.0356).


CONCLUSIONS
Bonding amalgam restorations to tooth structure in butt-joint cavities will reduce microleakage of both admixed and spherical amalgam restorations. Thermal stress does not affect the bond adversely.
Lombard
R
R
Operative Dentistry, University of Limpopo (Medunsa campus), South Africa. riaan@medunsa.ac.za
du Preez
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IC
Oberholzer
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TG
D000134:Acid Etching, Dental; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D004396:Coloring Agents; D003722:Dental Alloys / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification; D003743:Dental Enamel / Q000648:ultrastructure; D003763:Dental Leakage / Q000145:classification*; D003793:Dental Restoration, Permanent / Q000145:classification / Q000379:methods; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012394:Rosaniline Dyes; D013696:Temperature
C070606:Amalgambond; C433205:Calibra; D004396:Coloring Agents; D003722:Dental Alloys; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D012394:Rosaniline Dyes; C072541:Duo Cement; C033470:Dispersalloy; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C025485:basic fuchsin; D003723:Dental Amalgam