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Evaluation of two post core systems using two different methods (fracture strength test and a finite elemental stress analysis)
Scopus
Toplam 193 atıf DOI
The aim of this study was to compare a fiber composite laminate (FCL) post core and a conventional cast post core system by using two different methods. The first method was a conventional fracture strength test, and the second was a finite elemental stress-analysis method (FEM). For the conventional fracture strength test, 20 extracted, human upper, central incisors were used. The teeth were decoronated, treated endodontically, and restored with two post core systems. After embedding the samples in resin blocks, a loading force was applied to the teeth at a crosshead speed of 5 mm/ min at an angle of 45 degrees to the long axis of the ooth. The data were recorded, and the results were compared by using the Mann-Whitney U test. There was no statistically significant difference between the two post systems (p>0.05). For FEM analysis, a pseudo three-dimensional model of a maxillary central incisor, theoretically restored with either a cast post or an FCL, was used. The analysis was performed by using the structural analysis program (SAP90). FEM analysis showed that stress was accumulated within the cast post core system, and transmission of stress to supportive structures and the tooth was low. This is an advantage for tooth and supporting tissues. When the FCL post core system was evaluated by FEM, the results indicated that this system transferr stress to supportive structures and the tooth while stress accumulation within the post system was low. This is an advantage for the restoration but disadvantage for the supporting tissues. Copyright © 2002 by The American Association of Endodontists.
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Microleakage of endodontically treated teeth with different dowel systems
Scopus
Havuzumuzda 42 atıf almış
Statement of problem 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. Purpose The purpose of this in vitro study was to compare microleakage of 3 esthetic, adhesively luted dowel systems with a conventional dowel system. Material and 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 (α=.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). Conclusion 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.
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Kurumlar (1)
Selçuk Üniversitesi
Selçuklu, Turkey