Effect of an adhesive resin luting agent on the dowel-head retention of three different core materials

Titanium posts and bonded amalgam core longevity: A 22-year clinical survival retrospective study

BACKGROUND

The authors conducted a retrospective study to evaluate the long-term (18-22 years) clinic results of titanium post and bonded amalgam core restorations with metal-ceramic crowns placed in patients.

METHODS

From 1992 through 1996, the authors placed 88 restorations in 66 patients. They measured the ferrule effect in the minor dentin collar area. In 2014, the authors analyzed the following variables: ferrule length, length and thickness of the post, and tooth position.

RESULTS

The overall survival of the restorations decreased over time with survival rates of 89.6% after 5 years of follow-up appointments and 64.2% after 18 years of follow-up appointments. There were 42 failures, and the maxillary premolars had the most failures. The teeth with 2 or more millimeters ferrule length had a higher survival rate than those with a 0 to less than 2 mm ferrule length; these results were not statistically significant.

CONCLUSIONS

Statistically significant differences were detected according to the location of the tooth. The cores in the anterior teeth were 3.26 times more likely to fail than those in the molars, which presented higher survival rates; maxillary premolars had the most failures (28.5%). Both the metallic post length and its diameter did not influence restoration survival. The ferrule length was not statistically significant.

PRACTICAL IMPLICATIONS

The clinical technique to restore endodontically treated teeth that includes a titanium post and bonded amalgam restorations results in greater coronal destruction but shows good long-term results, ease of fabrication, and modest cost in comparison with other techniques.

Durability of the bond between resin composite cores and prefabricated posts

OBJECTIVES

This study evaluated the effect of post surface treatment and of storage condition on the bond between resin composite cores (Clearfil Core) and posts of titanium alloy (Fysika), silica-zircon fiber reinforced epoxy resin (SiliciumPost), and zirconia (CosmoPost).

MATERIAL AND METHODS

In the experimental groups, the coronal part of each post received sandblasting or tribochemical silicate-coating (CoJet) treatment. The coronal part of each post was embedded in a cylinder of resin composite core material with the aid of a fixation apparatus. After 15 min, the specimen was freed from the mold and stored in de-ionized water. The axial tensile strength (ATS) of posts was determined in a Universal Testing Machine when extracting the posts from the resin composite cores after: 1) 14 d water storage at 37°C, 2) 14 d water storage at 37°C followed by thermal cycling (6,000 cycles between 5°C and 55°C), or 3) 1 year water storage at 37°C. The results were statistically analyzed by three-way factorial ANOVA and Newman-Keuls' multiple range test.

RESULTS

The ATS values were generally higher for Fysika posts and SiliciumPost posts than for CosmoPost posts. Surface treatment effectively improved the ATS values of Fysika posts and SiliciumPost posts, but not those of CosmoPost posts. Thermal cycling or long-term water storage had only minimal effect on the ATS values of the posts.

CONCLUSION

Bonding of resin composite cores to the posts depended more on the material of the post and the surface treatment of posts than on the storage condition.

Resistance of three new esthetic post-and-core systems to compressive loading

STATEMENT OF PROBLEM

Despite their esthetic properties, the fracture resistance of newly introduced esthetic post-and-core systems has not been studied, restricting clinical use.

PURPOSE

The purpose of this study was to determine and compare the fracture resistances of 3 recently introduced esthetic post-and-core systems with a cast metal post and core using a clinically related test method.

MATERIAL AND METHODS

Forty recently extracted caries-free maxillary central incisors were selected, sectioned, and their roots endodontically treated. The roots were then embedded in acrylic resin blocks and assigned to 4 experimental groups (n = 10). The cast metal (Wiron 99) post-and-core group (CMDC) served as the control. Three experimental groups consisted of a stainless steel post/composite-resin (Charisma) core group (SCOM), zirconium dioxide post/composite-resin (Charisma) core group (ZCOM), and zirconium dioxide post/ceramic (Cosmopost) core group (ZCER). The post spaces were prepared, posts were seated, cores were formed, and 40 post-and-core foundations were cemented into the roots. Following thermal cycling (5000 cycles between 5 degrees C and 55 degrees C with a dwell time of 30 seconds), a compressive load was applied to the inclined surface of each specimen at a 130-degree angle to the specimen long axes in a universal testing machine at a crosshead speed of 1 mm/min until failure occurred. Force to failure (N) was recorded. Data were analyzed with a 1-way analysis of variance and Bonferroni tests to determine the difference between the groups (alpha=.05). For pairwise comparisons among group mean values, P < .0083 indicated statistical significance and established the overall confidence level at 95%.

RESULTS

Groups CMDC (738.6 N +/- 10.2) and ZCER (710.2 N +/- 5.3) exhibited the highest resistance to fracture. The ZCOM group showed the lowest fracture resistance (450.3 N +/- 5.7). The fracture resistance of the SCOM group (565 N +/- 7.2) was lower than the CMDC and ZCER groups, and higher than the ZCOM group. The differences among the groups were significant (P < .001) except for CMDC and ZCER (P < .016).

CONCLUSION

Within the limitations of this study, the cast metal post/core and zirconia post/ceramic core foundations were found to be more fracture resistant than the zirconia post/composite-resin core and stainless steel post/composite-resin core foundations. Aside from its desirable esthetic properties, the zirconia post/ceramic core combination demonstrated high resistance to fracture.