Fracture Resistance of Different Monolithic Zirconia Crowns with Horizontal and Vertical Finishing Lines: A Comparative in Vitro Study

Nasir, Mohammed Qasim; Kadhim, Alaa Jawad

doi:10.25130/tjds.12.2.11

	Fracture Resistance of Different Monolithic Zirconia Crowns with Horizontal and Vertical Finishing Lines: A Comparative in Vitro Study
Tikrit Journal for Dental Sciences
Volume 12, Issue 2, December 2024, Pages 360-369 PDF (577.68 K)
DOI: 10.25130/tjds.12.2.11
Authors
Mohammed Qasim Nasir^* ¹; Alaa Jawad kadhim²
¹(1) Department of Restorative and Aesthetic Dentistry, College of Dentistry, University of Baghdad, Iraq
²Department of Restorative and Aesthetic Dentistry, College of Dentistry, University of Baghdad, Iraq
Abstract
Objective: The primary objective was to examine how different preparation techniques and zirconia materials affected fracture strength. Materials and methods: 48 sound human maxillary first premolars of similar shape and size were used, categorized into two main groups of 24 teeth, as per the preparation technique: Group A: chamfer preparation design. Group B: vertical preparation design. Then, based on the type of material, each main group was subcategorized into three subgroups of eight teeth: IPS emax Zircad LT, IPS emax MT and IPS emax Prime (IvoclarVivadent). All the samples, prepared by the same operator, with the assistance of a dental surveyor. Intra-oral scanning was performed on the prepared teeth. The SironaInLab CAD 20.0 software was used to design crowns and were subsequently generated using a 5-axis milling machine. Self-adhesive resin cement was used to bond crowns to their respective teeth. To assess the crown's fracture strength, a computer-controlled universal testing system was used, which records the fracture strength automatically in each sample in Newton (N) during a single load-to-failure test. Burke's classification was employed to assess the fracture mode by analyzing each sample under a 40x digital microscope. The collected data were evaluated using statistical analysis using the independent t-test and ANOVA, with a 0.05 significance level. Results: Vertical preparation technique had higher fracture strength than the chamfer preparation technique with a statistically significant difference (p < 0.05). While comparable fracture resistance was identified across various monolithic zirconia crowns. All samples demonstrated a severe fracture of the crown and/or tooth (Code V). Conclusion: The vertical preparation design illustrated significantly better fracture strength than the chamfer preparation design, Materials comparisons showed comparable fracture resistance.
Keywords
Chamfer preparation Fracture resistance Mon

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