Fatigue and failure analysis of restored endodontically treated maxillary incisors without a dowel or ferrule.

Autor: de Carvalho MA; Professor, Department of Oral Rehabilitation, School of Dentistry, Evangelic University of Goias (UniEVANGÉLICA), Anápolis, GO, Brazil., Lazari-Carvalho PC; Professor, Department of Oral Rehabilitation, School of Dentistry, Evangelic University of Goias (UniEVANGÉLICA), Anápolis, GO, Brazil. Electronic address: lazari.pcl@gmail.com., Del Bel Cury AA; Full Professor, Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas (UNICAMP), Piracicaba, SP, Brazil., Magne P; Tenured Associate Professor, Don & Sybil Harrington Foundation Professor of Esthetic Dentistry, Department of Restorative Sciences, The Herman Ostrow School of Dentistry, University of Southern California (USC), Los Angeles, Calif.
Jazyk: angličtina
Zdroj: The Journal of prosthetic dentistry [J Prosthet Dent] 2024 Feb; Vol. 131 (2), pp. 241-250. Date of Electronic Publication: 2022 Jun 12.
DOI: 10.1016/j.prosdent.2021.07.007
Abstrakt: Statement of Problem: Information on the survival and mode of failure of endodontically treated incisors without a ferrule and restored without dowels is lacking.
Purpose: The purpose of this in vitro study was to compare the survival and failure mode of endodontically treated incisors without a ferrule and restored with bonded ceramic crowns and various composite resin foundation restorations without dowels with a control group with fiber dowels.
Material and Methods: Forty-five decoronated endodontically treated bovine incisors without ferrule were divided into 3 experimental groups and restored with different adhesive foundation restorations without dowel: nanohybrid composite resin (Nd), bulk-fill composite resin foundation restoration (NdB), and fiber-reinforced bulk-fill composite resin (NdFR). A control group with conventional foundation restorations (glass-fiber dowel with nanohybrid composite resin foundation restoration without ferrule) (D) was included for comparison. All teeth were prepared to receive bonded lithium disilicate ceramic crowns luted with dual-polymerizing composite resin cement and were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the incisal edge at an angle of 30 degrees and a frequency of 5 Hz, beginning with a load of 100 N (5000 cycles). A 100-N load increase was applied each 15 000 cycles. Specimens were loaded until failure or to a maximum for cycles endured of 1000 N (140 000 cycles). Groups were compared by using the Kaplan-Meier survival analysis (log rank test at α=.05 and pairwise post hoc comparisons) and life table analysis for load-at-failure (followed by Wilcoxon pairwise comparison α=.05).
Results: All the specimens failed before 140 000 load cycles. Even though no statistically significant differences were found between the experimental groups without dowel (P>.127), the fiber-reinforced foundation restoration yielded the highest mean ±standard deviation cycles to failure (46 023 ±4326) compared with Nd (38 899 ±2975) and NdB (39 751 ±2998). NdFR, however, outperformed the foundation restoration with glass-fiber dowel (35 026 ±2687) (P<.05). Most failure in groups without dowel were restorable, while 100% of catastrophic failure (unrestorable) were found in the group with dowels.
Conclusions: Based on the present in vitro study, dowels did not improve the performance of the adhesive restoration of endodontically treated incisors without a ferrule. The use of a short fiber-reinforced composite resin foundation restoration without a dowel was able to not only improve the resistance of the restorations compared with adhesive foundation restorations with dowels but also minimize catastrophic failures.
(Copyright © 2021 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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