Dissertation/Thesis Abstract

Flexural Strength of Three-Unit Monolithic Zirconia FPD with Different Size of Connectors Sintered in SpeedFire Oven
by Bahraini, Behshid, M.S., Tufts University School of Dental Medicine, 2020, 65; 28027947
Abstract (Summary)

Aim of the study: The aim of this in vitro study was to investigate the flexural strength of three-unit monolithic zirconia FPD with different size of connectors sintered in the SpeedFire Oven.

Materials & Methods: Thirty-five three-unit zirconia (In-Coris TZI C Medi S A1, Sirona Dental Systems GmbH, Bensheim, Germany) FPDs with different connector sizes were milled, sintered, and glazed. Three groups were formed based on the connector size: Group A: 3x3 mm, Group B: 3x4 mm and Group C: 4x4 mm. Flexural strength was calculated in MPa with the aid of a universal testing machine (Model 5566; Instron Corp, Canton, MA) along with the determination of mode of failure. The force was applied at the center of the bridge at a crosshead speed of 0.5mm/min, until it cracked.

Results: Group A had the highest mean flexural strength (1160.71MPa with a standard deviation of 140.70). One-way ANOVA comparing the groups was statistically significant (p<0.001). Post hoc tests using the Tukey-Kramer test showed significant differences between Groups A and B (p<0.001) and Groups A and C (p<0.001), but not Groups B and C (p=0.698). 74.3% of the fractures occurred in the connector part of FPDs and 25.7% happened in the margin of restorations. Concerning the mode of failure, based on Fisher's exact test, the difference between groups was not statistically significant. (p=0.717).

Conclusions:

1- Flexural strength of three-unit FPDs with connector sizes 3x3mm sintered in the SpeedFire oven was significantly higher than that of three-unit FPDs with connector sizes 3×4 mm and 4×4 mm.

2- Group A, three-unit FPDs with connector sizes 3x3mm, that were sintered with the short sintering protocol had clinically acceptable flexural strength while the other two groups did not have acceptable flexural strength.

Indexing (document details)
Advisor: Ali, Ala
Commitee: Papathanasiou, Aikaterini, Kostagianni, Aikaterini, Finkelman, Mathew D.
School: Tufts University School of Dental Medicine
Department: Posthodontics
School Location: United States -- Massachusetts
Source: MAI 82/1(E), Masters Abstracts International
Source Type: DISSERTATION
Subjects: Dentistry, Materials science
Keywords: Fast sintering, Speedfire oven, Zirconia connector size, Zirconia flexural strength, Zirconia FPD, Zirconia sintering
Publication Number: 28027947
ISBN: 9798662449749
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