Microleakage of endodontically treated teeth with different dowel systems.
BACKGROUND
Several new esthetic dowel systems are available for the restoration of endodontically treated teeth, but little is known about how effectively these dowels seal the restored teeth.


OBJECTIVE
The purpose of this in vitro study was to compare microleakage of 3 esthetic, adhesively luted dowel systems with a conventional dowel system.


METHODS
The root canals of 41 human intact single-rooted extracted teeth were prepared using a step-back technique. The teeth were randomly divided into 4 experimental groups (n=10), and 1 tooth served as a positive control. The decoronated roots were obturated with gutta-percha using lateral condensation. Roots were restored with 1 of the following dowel systems according to the manufacturer's instructions: (1) stainless steel dowels (ParaPost), (2) glass fiber dowels (Snowpost), (3) resin-supported polyethylene fiber (Ribbond) dowels, or (4) zirconia dowels (Cosmopost). Using a fluid filtration method, coronal leakage of the specimens along the dowel space and root canal restorative material was measured. Fluid movement measurements were made at 2-minute intervals for 8 minutes to measure the presence of voids existing in the obturated canals, at 1 week, 3 months, and 6 months following dowel insertion. A repeated-measures analysis of variance (ANOVA) was used to analyze logarithmic transformations of data (time and dowel material) for significant differences. The Tukey HSD test and paired 2-tailed tests were used to perform multiple comparisons (alpha=.05).


RESULTS
The data indicated that the leakage values varied according to the dowel system used (P<.01). There was significant interaction between dowel systems and time of testing (P<.01). The sealing ability of zirconia dowels decreased over time (P<.01), but sealing abilities of stainless steel and resin-supported polyethylene fiber dowels remained constant (P>.05). The sealing ability of glass fiber dowels increased at 3 months (P=.032) and remained constant over the next 3 months (P=.758). Statistically, resin-supported polyethylene fiber and glass fiber dowels showed the lowest coronal leakage when compared with stainless steel and zirconia dowels at all time periods (P<.01). There were no significant differences between resin-supported polyethylene fiber and glass fiber dowels at any time period. The initial leakage measurement in zirconia dowel and stainless steel dowels were similar (P=.914), but became significantly different at 3 and 6 months (P<.01).


CONCLUSIONS
Resin-supported polyethylene fiber dowels and glass fiber dowels tested exhibited less microleakage compared to zirconia dowel systems. The latter system should be further evaluated because of its unacceptable level of leakage.
Usumez
Aslihan
A
Department of Prosthodontics, Faculty of Dentistry, University of Selcuk, Konya, Turkey. asli_u@hotmail.com
Cobankara
Funda Kont
FK
Ozturk
Nilgun
N
Eskitascioglu
Gurcan
G
Belli
Sema
S
D000180:Acrylic Resins / Q000737:chemistry; D000704:Analysis of Variance; D001840:Dental Bonding; D003763:Dental Leakage / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D003786:Dental Pulp Cavity / Q000648:ultrastructure; D005898:Glass / Q000737:chemistry; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D016014:Linear Models; D016555:Matched-Pair Analysis; D011076:Polycarboxylate Cement / Q000737:chemistry; D011095:Polyethylenes / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry; D012390:Root Canal Therapy; D013193:Stainless Steel / Q000737:chemistry; D013997:Time Factors; D019553:Tooth, Nonvital / Q000534:rehabilitation*; D015040:Zirconium / Q000737:chemistry
D000180:Acrylic Resins; D003764:Dental Materials; D011076:Polycarboxylate Cement; D011095:Polyethylenes; C084063:RIBBOND; D019279:Resin Cements; C009753:fiberglass; D013193:Stainless Steel; D006171:Gutta-Percha; D015040:Zirconium; C028541:zirconium oxide