Fracture resistance of partial coverage retainer designs on posterior zirconia fixed dental prostheses

Abd-Elfatah, Ahmed Bahy-Eldeen; Madina, Manal mohammed; elzordok, walid abd_elghafar

doi:10.21608/dusj.2025.349804.1106

	Fracture resistance of partial coverage retainer designs on posterior zirconia fixed dental prostheses
Delta University Scientific Journal
Volume 8, Issue 1, April 2025, Page 49-61 PDF (438.45 K)
Document Type: Original research papers
DOI: 10.21608/dusj.2025.349804.1106
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Authors
Ahmed Bahy-Eldeen Abd-Elfatah ¹; Manal mohammed Madina²; walid abd_elghafar elzordok³
¹Fixed prosthodontics, faculty of dentistry, delta university of science and technology, Gamsaa, Egypt
²Professor, Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University and Delta University for Science and Technology, Mansoura, Egypt
³Professor, Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt
Abstract
Abstract Aim: Investigate the impact of partial coverage retainer designs on fracture resistance of monolithic zirconia posterior fixed dental prostheses. Methods: Eighteen caries-free human mandibular second premolars and molars were divided according to the retainer designs of zirconia fixed prostheses with first molar pontic into three groups (n=9): retentive one wing, lingual and buccal cusps coverage (I), non-retentive one wing, lingual and buccal cusps coverage (II). All specimens for 10,000 cycles were thermo-cycled (5-55°C) and dynamically loaded (50 N, 240,000 cycles, 1.6 Hz), then compressive axially loaded until fracture. Data were analyzed with one-way ANOVA test statistically followed by Tukey HSD (P< 0.05). Results: Group I showed the lowest failure load, while the highest one was recorded for control group II. Group I was not statistically significant (P<0.001) compared to the other group. Conclusions: The non-retentive retainer designs involved more enamel surface area coverage in group II, enhanced the fracture resistance of minimal invasive partial coverage retained posterior zirconia fixed prostheses, rather than designs involved dentinal retentive features in group I. Clinical relevance was that the clinicians should be attentive to physiologic functional posterior force for every case during the selection of partial coverage retainer designs retained posterior zirconia fixed prostheses.
Keywords
KEY WORDS: partial coverage retainers; fracture; monolithic zirconia posterior fixed dental prostheses


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