In vitro evaluation of the retention of composite fiber and stainless steel posts.
OBJECTIVE
This study compared the tensile retentive strength of composite fiber-reinforced dowels luted with a resin cement to stainless steel dowels luted with zinc phosphate cement.


METHODS
The crowns of 40 extracted human mandibular premolars were removed with a separating disc 1-mm coronal to the cementoenamel junction. The teeth were randomly divided into 4 groups (n = 10). A post space was prepared in each specimen to a depth of 9 mm, using the drill supplied by the respective manufacturer. For the stainless steel post group, 1.25-mm-diameter posts were cemented with zinc phosphate cement. For the composite fiber reinforced groups, posts with diameters of 1.00, 1.25, and 1.50 mm were luted with a Bisphenol A-Glycidyl Methacrylate (BIS-GMA) resin bonding system (Jeneric/Pentron, Wallingford, CT) according to manufacturer specifications. The specimens were stored in a sealed container with a moist environment for 24 hours, placed in a fixture in an 801 Materials Test Systems (MTS) machine (MTS Systems Corp, Minneapolis, MN), and loaded in tension at a rate of 5.0 mm/min until failure. Differences among the 4 groups were determined using a one-way analysis of variance and Tukey-B post-hoc tests (alpha = 0.05).


RESULTS
The mean loads to failure ranged from 43.9 +/- 10.4 kg for the stainless steel dowel group to 19.9 +/- 5.7 kg for the composite fiber-reinforced 1.00-mm-diameter group. The stainless steel post luted with zinc phosphate cement provided significantly greater tensile resistance than all composite fiber dowel groups. The retention of the 1.00-mm composite fiber-reinforced post was significantly less than the remaining groups.


CONCLUSIONS
Under the conditions of this study, the stainless steel dowel luted with zinc phosphate cement provided significantly greater retention.
Gallo
John R
JR
LSUHSC School of Dentistry, New Orleans, LA 70119, USA. jgallo@lsuhsc.edu
Miller
Troy
T
Xu
Xiaoming
X
Burgess
John O
JO
D000704:Analysis of Variance; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002484:Cementation; D003188:Composite Resins / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry*; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013718:Tensile Strength; D019231:Tooth Preparation, Prosthodontic / Q000295:instrumentation; D015036:Zinc Phosphate Cement / Q000737:chemistry
D003188:Composite Resins; D003722:Dental Alloys; C113550:FiberKor, sculpture; D019279:Resin Cements; C009753:fiberglass; D013193:Stainless Steel; D017438:Bisphenol A-Glycidyl Methacrylate; D015036:Zinc Phosphate Cement