Statement Of Problem: The influence of the flexural modulus of prefabricated posts on the fracture resistance of endodontically treated teeth is unclear.
Purpose: The purpose of this in vitro study was to evaluate the influence of post material and post diameter on the fracture resistance of endodontically treated mandibular premolars. In addition, the influence of tooth substance loss was evaluated by comparing 1 with 2 residual dentinal walls.
Material And Methods: Sixty-four extracted mandibular first premolars were endodontically treated and divided into 8 test groups (n=8) based on the number of residual walls (1 or 2), post material (glass fiber or titanium) and post diameter (International Standards Organization [ISO] 70 or ISO 90). After luting the posts, the specimens received a composite resin core and a crown preparation with a 2-mm ferrule. Cast Co-Cr crowns were cemented with glass ionomer cement. After 1 200 000 mastication cycles with a load of 49 N and simultaneous thermocycling (5 °C-55 °C), specimens were quasistatically loaded at 30 degrees to the longitudinal axis of the tooth until fracture. Fracture loads were analyzed by using 3-way ANOVA (α=.05). Fracture modes were examined with a stereomicroscope at ×25 magnification and recorded.
Results: Fracture loads ranged from 954 ±35 N (1 residual wall-glass fiber-ISO 70) to 1286 ±202 N (1 residual wall-glass fiber-ISO 90). Titanium posts showed a statistically significant higher fracture resistance than glass fiber posts. A statistically significant increase in fracture resistance was also observed with increasing post diameter. However, no significant difference was found with respect to the number of residual walls (P>.05).
Conclusions: Teeth restored with titanium posts exhibited higher fracture resistance than teeth restored with glass fiber posts, especially when smaller diameter posts were used.
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http://dx.doi.org/10.1016/j.prosdent.2020.05.002 | DOI Listing |
BMC Oral Health
December 2024
Department of Biomaterials Science and Turku Clinical Biomaterial Center -TCBC, Institute of Dentistry, University of Turku, Turku, Finland.
Background: Short fiber-reinforced composites (SFRCs) are restorative materials for large cavities claimed to effectively resist crack propagation. This study aimed to compare the mechanical properties and physical characteristics of five commercially available SFRCS (Alert, Fibrafill Flow, Fibrafill Dentin, everX Flow, and everX Posterior) against a conventional particulate-filled composite (PFC, Essentia Universal).
Methods: The following characteristics were evaluated in accordance with ISO standards: flexural strength and modulus and fracture toughness.
Dent Res J (Isfahan)
November 2024
Department of Orthodontics and Dentofacial Orthopedics, SRM Dental College and Hospital, Chennai, Tamil Nadu, India.
Background: The aim of this study was to compare the mechanical properties of the polymer brackets with metal and ceramic brackets and verify if the polymer brackets could be used clinically.
Materials And Methods: A thorough search was conducted in four electronic databases, including Scopus, PubMed, Cochrane, Ovid, and Lilacs, with article selection based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis standards. A computerized search of the database was done from January 1990 to June 2024.
Infect Drug Resist
December 2024
Department of Laboratory Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, People's Republic of China.
Objective: is usually found in urogenital tract infections and is associated with several extra-genitourinary infections, including septic arthritis, bacteremia, and meningitis. Here, we report a rare case of induced bloodstream infection with thoracic inflammation in a surgical patient.
Methods: A 56-year-old male who underwent surgery for multiple pelvic and rib fractures developed fever, pleural effusion, and wound exudation despite receiving prophylactic anti-infection treatment with cefotiam.
Fatigue cracking of rib-to-deck conventional single-sided welded joints is a prevalent issue in orthotropic steel decks (OSDs), significantly impacting their structural integrity and durability. Rib-to-deck innovative double-sided welded joints have the potential to enhance the fatigue resistance of OSD. However, Welding Residual Stresses (WRS) significantly influence the fatigue life of these joints, mandating its consideration in fatigue assessments.
View Article and Find Full Text PDFJ Endod
December 2024
State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, 237# Luoyu Road, Wuhan 430079, People's Republic of China. Electronic address:
Introduction: This study aimed to assess the effect of cavity designs on instrumentation, obturation and fracture resistance for mandibular first premolars with Vertucci V canal.
Methods: Mandibular first premolars with Vertucci V canal were scanned with micro-CT. 20 teeth with moderately curved canal were prepared with conservative endodontic cavity (CEC/M) or traditional endodontic cavity (TEC/M), and 30 with severely curved canal were prepared with CEC (CEC/S), modified CEC (MCEC/S) or TEC (TEC/S).
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