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Fracture strength after dynamic loading of endodontically treated teeth restored with different post-and-core systems.
J Prosthet Dent. 2002 Apr; 87(4):438-45.JP

Abstract

STATEMENT OF PROBLEM

Prefabricated metal and ceramic posts can be used with direct or indirect cores as an alternative to the conventional cast post and core. It is unclear how the fracture strength of zirconia posts with composite or ceramic cores and titanium posts with composite cores compares to the fracture strength of gold posts and cores after dynamic loading.

PURPOSE

This study compared the fracture strength of endodontically treated, crowned maxillary incisors with limited ferrule length and different post-and-core systems after fatigue loading.

MATERIAL AND METHODS

Sixty-four caries-free, human maxillary central incisors were divided into 4 groups. After root canal treatment, Group 1 was restored with titanium posts and composite cores, Group 2 with zirconia posts and composite cores, and Group 3 with zirconia posts and heat-pressed ceramic cores. Teeth restored with cast-on gold posts and cores served as the controls (Group 4). Teeth were prepared with a circumferential shoulder including a 1 to 2 mm ferrule; all posts were cemented with an adhesive resin cement, restored with complete-coverage crowns, and exposed to 1.2 million load cycles (30 N) in a computer-controlled chewing simulator. Simultaneous thermocycling between 5 degrees C and 55 degrees C was applied for 60 seconds with an intermediate pause of 12 seconds. All specimens that did not fracture during dynamic loading were loaded until fracture in a universal testing machine at a crosshead speed of 1.5 mm/min; loads were applied at an angle of 130 degrees at the incisal edge. Fracture loads (N) and modes (repairable or catastrophic) were recorded. The Kruskal-Wallis test was used to compare fracture loads among the 4 test groups. Analyses were conducted both with and without the specimens that failed during the chewing simulation. A Fisher exact test was performed to detect group differences in fracture modes. A significance level of P<.05 was used for all comparisons.

RESULTS

The following survival rates were recorded after the chewing simulation: 93.8% (Group 1), 93.8% (Group 2), 100% (Group 3), and 87.5% (Group 4). The median fracture strengths for Groups 1 to 4 were 450 N, 503 N, 521 N, and 408 N, respectively. No significant differences were detected among the groups. The use of zirconia posts resulted in a nonsignificant lower number of catastrophic root fractures.

CONCLUSION

Within the limitations of this study, the results suggest that zirconia posts with ceramic cores can be recommended as an alternative to cast posts and cores. If a chairside procedure is preferred, zirconia or titanium posts with composite cores can be used. Clinical trials are required to verify these in vitro results.

Authors+Show Affiliations

Department of Biological and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, USA. heydecke@umich.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

12011861

Citation

Heydecke, Guido, et al. "Fracture Strength After Dynamic Loading of Endodontically Treated Teeth Restored With Different Post-and-core Systems." The Journal of Prosthetic Dentistry, vol. 87, no. 4, 2002, pp. 438-45.
Heydecke G, Butz F, Hussein A, et al. Fracture strength after dynamic loading of endodontically treated teeth restored with different post-and-core systems. J Prosthet Dent. 2002;87(4):438-45.
Heydecke, G., Butz, F., Hussein, A., & Strub, J. R. (2002). Fracture strength after dynamic loading of endodontically treated teeth restored with different post-and-core systems. The Journal of Prosthetic Dentistry, 87(4), 438-45.
Heydecke G, et al. Fracture Strength After Dynamic Loading of Endodontically Treated Teeth Restored With Different Post-and-core Systems. J Prosthet Dent. 2002;87(4):438-45. PubMed PMID: 12011861.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Fracture strength after dynamic loading of endodontically treated teeth restored with different post-and-core systems. AU - Heydecke,Guido, AU - Butz,Frank, AU - Hussein,Amr, AU - Strub,Jörg R, PY - 2002/5/16/pubmed PY - 2002/8/14/medline PY - 2002/5/16/entrez SP - 438 EP - 45 JF - The Journal of prosthetic dentistry JO - J Prosthet Dent VL - 87 IS - 4 N2 - STATEMENT OF PROBLEM: Prefabricated metal and ceramic posts can be used with direct or indirect cores as an alternative to the conventional cast post and core. It is unclear how the fracture strength of zirconia posts with composite or ceramic cores and titanium posts with composite cores compares to the fracture strength of gold posts and cores after dynamic loading. PURPOSE: This study compared the fracture strength of endodontically treated, crowned maxillary incisors with limited ferrule length and different post-and-core systems after fatigue loading. MATERIAL AND METHODS: Sixty-four caries-free, human maxillary central incisors were divided into 4 groups. After root canal treatment, Group 1 was restored with titanium posts and composite cores, Group 2 with zirconia posts and composite cores, and Group 3 with zirconia posts and heat-pressed ceramic cores. Teeth restored with cast-on gold posts and cores served as the controls (Group 4). Teeth were prepared with a circumferential shoulder including a 1 to 2 mm ferrule; all posts were cemented with an adhesive resin cement, restored with complete-coverage crowns, and exposed to 1.2 million load cycles (30 N) in a computer-controlled chewing simulator. Simultaneous thermocycling between 5 degrees C and 55 degrees C was applied for 60 seconds with an intermediate pause of 12 seconds. All specimens that did not fracture during dynamic loading were loaded until fracture in a universal testing machine at a crosshead speed of 1.5 mm/min; loads were applied at an angle of 130 degrees at the incisal edge. Fracture loads (N) and modes (repairable or catastrophic) were recorded. The Kruskal-Wallis test was used to compare fracture loads among the 4 test groups. Analyses were conducted both with and without the specimens that failed during the chewing simulation. A Fisher exact test was performed to detect group differences in fracture modes. A significance level of P<.05 was used for all comparisons. RESULTS: The following survival rates were recorded after the chewing simulation: 93.8% (Group 1), 93.8% (Group 2), 100% (Group 3), and 87.5% (Group 4). The median fracture strengths for Groups 1 to 4 were 450 N, 503 N, 521 N, and 408 N, respectively. No significant differences were detected among the groups. The use of zirconia posts resulted in a nonsignificant lower number of catastrophic root fractures. CONCLUSION: Within the limitations of this study, the results suggest that zirconia posts with ceramic cores can be recommended as an alternative to cast posts and cores. If a chairside procedure is preferred, zirconia or titanium posts with composite cores can be used. Clinical trials are required to verify these in vitro results. SN - 0022-3913 UR - https://www.unboundmedicine.com/medline/citation/12011861/Fracture_strength_after_dynamic_loading_of_endodontically_treated_teeth_restored_with_different_post_and_core_systems_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022391302985008 DB - PRIME DP - Unbound Medicine ER -