Retention of posts with resin, glass ionomer and hybrid cements.
OBJECTIVE
To measure and compare the retention of serrated root canal posts cemented with glass ionomer, resin and resin-modified glass ionomer (hybrid) cements.


METHODS
Fifty single-rooted human teeth were decoronated, treated endodontically and then embedded in resin blocks. Standard post-holes, 10 mm long, were prepared to receive 1.5 mm serrated stainless steel posts. Five equal-sized groups of roots had posts cemented using either a glass ionomer cement, one of two resin cements or one of two resin-modified glass ionomer luting cements. The cements were prepared and used according to the manufacturers' instructions. The tensile force required to dislodge the cemented posts in a testing machine was recorded. Statistical analysis was performed using Student's t-test and Mann-Whitney U-tests at the 99.9% confidence level.


RESULTS
Statistical analysis revealed that posts cemented with resin A were significantly better retained (340.06 N+/-23.13 N) than those cemented with resin B (212.56 N+/-67.62 N), or either of the two resin-modified glass ionomer cements (53.90 N+/-28.42 N, 25.97 N+/-14.70 N), but not statistically better than posts cemented with the glass ionomer cement (286.16 N+/-38.71 N). The retention of posts cemented with either resin B or the glass ionomer cement was significantly better than with either hybrid cement. There was no significant difference in retention between the hybrid cements.


CONCLUSIONS
The performance of the resin-modified glass ionomer cements was significantly below that of alternative cements in this study. Possible explanations for this finding are discussed. Dentists should be cautious in adopting this new cementing regime.
Love
R M
RM
Department of Restorative Dentistry, University of Otago School of Dentistry, Dunedin, New Zealand.
Purton
D G
DG
D002484:Cementation; D003188:Composite Resins / Q000737:chemistry; D016001:Confidence Intervals; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis / Q000295:instrumentation; D003781:Denture Retention; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008277:Magnesium Oxide / Q000737:chemistry; D008422:Materials Testing; D010710:Phosphates / Q000737:chemistry; D011076:Polycarboxylate Cement / Q000737:chemistry; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry; D012390:Root Canal Therapy; D013193:Stainless Steel; D013718:Tensile Strength; D014092:Tooth Root; D015034:Zinc Oxide / Q000737:chemistry
D003188:Composite Resins; C113301:FujiPlus; D005899:Glass Ionomer Cements; C093719:Panavia TPN-S; D010710:Phosphates; D011076:Polycarboxylate Cement; D019279:Resin Cements; C084550:Vitremer; D013193:Stainless Steel; D008277:Magnesium Oxide; C040235:Ketac-cem; C041330:Scotchbond; D015034:Zinc Oxide