Microleakage of various cementing agents for full cast crowns.
OBJECTIVE
To evaluate microleakage and marginal gaps in full cast crown restorations bonded with six different types of cementing agents.


METHODS
Sixty non-carious human premolars and molars were prepared in a standardized manner for full cast crown restorations. The mesial and distal margins were located in dentin, while the vestibular and palatal/lingual margins were located in enamel. Crowns were made from a high-gold alloy using a standardized technique. The specimens were randomized to six groups of cementing agents: one zinc-phosphate cement (Harvard cement), one conventional glass-ionomer cement (Fuji I), one resin-modified glass-ionomer cement (Fuji Plus), two standard resin cements (RelyX ARC, Panavia F), and one self-adhesive universal resin cement (RelyX Unicem). After 4 weeks of storage in distilled water at 37 degrees C, the specimens were subjected to 5000 thermocycles ranging from 5 to 55 degrees C. Then, they were placed in a silver nitrate solution, embedded in resin blocks, and vertically cut in buccolingual and mesiodistal direction. Subsequently, the objects were evaluated for microleakage and marginal gap using a high-resolution digital microscope camera.


RESULTS
A number of inter-group differences were statistically significant. RelyX Unicem showed the smallest degree of microleakage both in enamel and in dentin. Panavia F und RelyX Unicem were associated with significantly larger marginal gaps than all other cementing agents. No association was observed between microleakage and marginal gap other than a weak direct correlation when using Harvard cement on enamel.


CONCLUSIONS
The cementing agents investigated revealed different sealing abilities. These differences were not associated with specific types of materials.
Piwowarczyk
Andree
A
Department of Prosthetic Dentistry, School of Dentistry, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany. piwowarczyk@t-online.de
Lauer
Hans-Christoph
HC
Sorensen
John A
JA
D017438:Bisphenol A-Glycidyl Methacrylate; D003442:Crowns; D001840:Dental Bonding; D003738:Dental Cements / Q000009:adverse effects; D003743:Dental Enamel; D003763:Dental Leakage / Q000209:etiology; D018772:Dental Marginal Adaptation; D003799:Dental Stress Analysis; D003804:Dentin; D005899:Glass Ionomer Cements; D006801:Humans; D008422:Materials Testing; D011092:Polyethylene Glycols; D011109:Polymethacrylic Acids; D011897:Random Allocation; D019279:Resin Cements; D018709:Statistics, Nonparametric; D019231:Tooth Preparation, Prosthodontic; D015036:Zinc Phosphate Cement
D003738:Dental Cements; D005899:Glass Ionomer Cements; C438843:Panavia-Fluoro; D011109:Polymethacrylic Acids; C483701:Rely X Unicem; C462240:RelyX ARC; D019279:Resin Cements; C084541:Fuji glass-ionomer lining cement; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D015036:Zinc Phosphate Cement; C074226:Harvard Cement