Methods for Dynamic Fracture Resistance Testing

1979 ◽  
pp. 43-65
Author(s):  
E. A. Lange
Keyword(s):  
Dynamic Fracture ◽  
Fracture Resistance ◽  
Resistance Testing

scholarly journals Effect of two formulations of 10% sodium ascorbate on fracture resistance of endodontically treated tooth submitted to dental bleaching with hydrogen peroxide associated titanium dioxide nanoparticles

2014 ◽  
Vol 2 (1) ◽  
pp. 13
Author(s):  
Francisco Carlos Bontorim ◽  
Milton Carlos Kuga ◽  
Sabrina Spinelli Cioffi ◽  
Marcus Vinicius Reis Só ◽  
Gisele Faria ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Fracture Resistance ◽  
Composite Resin ◽  
Positive Control ◽  
Sodium Ascorbate ◽  
Resistance Testing ◽  
Dental Bleaching ◽  
Endodontically Treated Tooth

PURPOSE: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. MATERIAL AND METHODS: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching  sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied  10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied  10SA, in aqueous solution formulation.  The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) RESULTS: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). CONCLUSIONS: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.

scholarly journals Effect of Thermo-Mechanical Aging and Repressing on Fracture Resistance of Lithium Disilicate Crowns

2021 ◽  
Vol 24 (3) ◽  
Author(s):  
Amr El-Etreby ◽  
Mahmoud Metwally ◽  
Gihan EL-Nagar
Keyword(s):  
Glass Ceramic ◽  
Fracture Resistance ◽  
Glass Ceramics ◽  
Lithium Disilicate ◽  
Mean Value ◽  
Resistance Testing ◽  
Novel Approach ◽  
Significant Difference ◽  
Keywords Fracture ◽  
Mechanical Aging

Objective: The recycling of heat pressed lithium disilicate glass-ceramic leftover material has been reported to be done by dental laboratories. The effect of this procedure on the fracture resistance of single crowns is unknown, especially when it is functioning inside the oral cavity with subsequent exposure to temperature changes and cycles of mastication. Material and Methods: A total of 28 lithium disilicate glass-ceramic crowns (IPS emax Press) were constructed and randomly assigned into two groups (n = 14); Group (P): Included crowns fabricated from new e.max ingots. Group (R): Included crowns fabricated from repressed e.max buttons. Specimens of each group were divided into two equal subgroups (n = 7) according to whether the aging of specimens will be performed or not before fracture resistance testing. Subgroup (N), samples were subjected to fracture resistance without thermo-mechanical aging, while subgroup (A), samples were subjected to thermo-cycling and cyclic loading before being subjected to fracture strength testing. Different methods; SEM, XRD, EDAX were used to characterize the properties of lithium disilicate glass-ceramics before and after repressing. Results: The highest statistically significant fracture resistance value was recorded for the subgroup (RN) repressed/non-aged, followed by the subgroup repressed/aged (RA), while the lowest statistically significant mean value was recorded for the subgroup pressed/aged (PA). There was no significant difference between pressed/non-aged (PN) and repressed/aged (RA) subgroups. Conclusion: Repressing of leftover buttons may increase the fracture resistance of IPS emax Press crowns. Thermo-mechanical aging may negatively affect the fracture resistance of IPS emax Press crowns, yet Repressing may decrease this effect. Clinical implications: This is a novel approach that targets a point of research that has not been investigated before. It elaborates how repressing may decrease the effect of aging and increase the fracture resistance of lithium disilicate crowns. Thus, recycling of lithium disilicate glass ceramics might decrease its failure and prolong their serviceability.   Keywords Fracture resistance; Heat pressed; Lithium disilicate; Recycling; Repressing; Thermo-mechanical aging.

Influence of Different Diameters and Materials of Posts on the Fracture Resistance of Endodontically Treated Teeth

2014 ◽  
Vol 633 ◽  
pp. 286-289
Author(s):  
Li Xian Zhang ◽  
Yu Xiao Liu ◽  
Ya Li Liu ◽  
Qiong Rong
Keyword(s):  
Fracture Resistance ◽  
Resistance Testing ◽  
Fiber Post ◽  
Endodontically Treated Teeth ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Different Diameters ◽  
Group D ◽  
Titanium Post

Objective: To evaluate the fracture resistance of endodontically treated teeth reinforced with cast titanium posts and prefabricated glass-fiber posts with different diameters. Materials and Methods: 50 recently extracted human maxillary central incisors were endodontically treated and randomly divided into 5 groups of 10 specimens each: Group A: 1.35mm diameter of cast titanium post; Group B: 1.5mm diameter of cast titanium post; Group C: 1.375mm diameter of prefabricated fiber post; Group D: 1.5mm diameter of prefabricated fiber post; Group E: resin restoration. All specimens were subjected to fracture resistance testing in a universal testing machine, statistical analysis was performed and the fracture modes were analyzed. Results: The mean fracture resistance of five groups as follows: 404.22±73.92N for group A, 488.17±78.68N for group B, 280.32±45.23N for group C, 317.53±50.87N for group D, 222.76±38.67N for group E. The fracture resistance of restored teeth between group C and group D had no significant difference (P>0.05). The fracture resistance of the rest pairwise group comparisons had significant difference (P<0.05). Most of cast post samples fractured at the root middle or apical portion, while most of the fiber post samples fractured at the root cervical or post fracture, which could be retreated. Conclusion: Human maxillary central incisors restored with cast posts could bear higher fracture load and fiber post could protect the root from fracture preferably.

scholarly journals Finite element analysis and fracture resistance testing of a new intraradicular post

2012 ◽  
Vol 20 (4) ◽  
pp. 427-434 ◽  
Author(s):  
Eron Toshio Colauto Yamamoto ◽  
Clovis Pagani ◽  
Eduardo Galera da Silva ◽  
Pedro Yoshito Noritomi ◽  
André Yugou Uehara ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Resistance ◽  
Resistance Testing ◽  
Element Analysis

scholarly journals Fracture resistance of endodontically treated teeth restored with resin post reinforced with glass fiber

2021 ◽  
Vol 14 (1) ◽  
pp. 81-85
Author(s):  
Mihaela Chirila ◽  
◽  
◽  
◽  
◽  
...  
Keyword(s):  
Glass Fiber ◽  
Fracture Resistance ◽  
Surface Friction ◽  
Axial Direction ◽  
Resin Cement ◽  
Resistance Testing ◽  
Endodontically Treated Teeth ◽  
Adhesive Resin ◽  
Gutta Percha ◽  
Root Dentin

This study aims to determine whether the design of resin posts reinforced with glass fiber (FRC) and Reporfost (Angelus, Londrina, PR, Brazil) significantly improves the fracture resistance of endodontically treated teeth restored through this method.A batch of 30 maxillary monoradicular teeth (15 central incisors, 15 canines) were treated endodontically by step-back technique (apical enlargement 40-K file) sealed with Sealapex (Kerr Corporation, Orange, US) and gutta-percha by lateral condensation, cold. They were divided into two equal groups, prepared for cementing the FRC posts. The Exacto posts (Angelus, Londrina, PR, Brazil) in group 1 and the Reforpost posts (Angelus; Londrina; PR, Brazil) were cemented with dual cure resin cement Breeze Self-Adhesive Resin Cement (Pentron Clinical, Orange, US). Fracture resistance testing was performed on the crown-apical axial direction, using the Hounsfield / Tinius Olsen H1-KS, PA, USA mechanical testing apparatus. The behavior of each tooth-post assembly was recorded as a graph. The statistical analysis was done using one way ANOVA (α=0.05). The differences between the Exacto post group and the Reforpost post group are not statistically significant (p = 0.466). The maximum force recorded was 970 N and the minimum 186N. The mean force at which the fracture occurred was approximately 500N for both groups. The strain test showed that modifying the Reforpost post design did not improve the fracture resistance parameters of the tooth-post assembly through increasing the surface friction or maintaining adhesion to the walls of the root dentin.

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