Journal article
Effect of preparation design and endodontic access on fracture resistance of zirconia overlays in mandibular molars: An in vitro study
Journal of prosthodontics, Vol.34(4), pp.412-421
04/2025
DOI: 10.1111/jopr.13865
PMCID: PMC11976686
PMID: 38734932
Abstract
To evaluate the fracture resistance of zirconia overlays, considering various preparation designs and the presence of endodontic access.
Ninety translucent zirconia (5Y-PSZ) overlay restorations were divided into six groups (n = 15/group) based on different preparation designs, with and without endodontic access: chamfer margin 4 mm above the gingival level without (group 1) and with endodontic access (group 2); margin 2 mm above the gingival level without (group 3) and with endodontic access (group 4); overlay with no chamfer margin without (group 5) and with endodontic access (group 6). Restorations were bonded to mandibular first molar resin dies, and the groups with endodontic access were sealed with flowable resin composite. All restorations underwent 100,000 cycles of thermal cycling between 5°C and 55°C, followed by loading until fracture. Maximum load and fracture resistance were recorded. ANOVA with Tukey post-hoc tests were used for statistical comparison (α < 0.05).
Fracture resistance significantly varied among overlay designs with and without endodontic access (p < 0.001), except for the no-margin overlays (groups 5 and 6). Overlays with a 2 mm margin above the gingival margin with endodontic access (group 4) exhibited significantly higher fracture resistance compared to both the 4-mm supragingival (group 2) and no-margin (group 6) designs, even when compared to their respective intact groups (groups 1 and 5). There were no significant differences between the no-margin and 4-mm supragingival overlays.
The more extensive zirconia overlay for mandibular molars is the first choice since the 2 mm margin above the gingival level design withstood considerable loads even after undergoing endodontic access. A no-margin overlay is preferred over the 4-mm supragingival design as it preserves more tooth structure and there was no outcome difference, irrespective of endodontic access. Caution is warranted in interpreting these findings due to the in vitro nature of the study.
Details
- Title: Subtitle
- Effect of preparation design and endodontic access on fracture resistance of zirconia overlays in mandibular molars: An in vitro study
- Creators
- Carlos A Jurado - University of Tennessee Health Science CenterKelvin I Afrashtehfar - University of BernManuel Robles - Universidad del Valle de MéxicoRazan S Alaqeely - King Saud UniversityHussain D Alsayed - King Saud UniversityTerry J Lindquist - University of IowaAbdulaziz Alhotan - King Saud University
- Resource Type
- Journal article
- Publication Details
- Journal of prosthodontics, Vol.34(4), pp.412-421
- DOI
- 10.1111/jopr.13865
- PMID
- 38734932
- PMCID
- PMC11976686
- NLM abbreviation
- J Prosthodont
- eISSN
- 1532-849X
- Grant note
- RSPD2024R790 / King Saud University
- Language
- English
- Electronic publication date
- 05/12/2024
- Date published
- 04/2025
- Academic Unit
- Prosthodontics
- Record Identifier
- 9984626997902771
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