scholarly journals Influence of Antagonist Material on Fatigue and Fracture Resistance of Zirconia Crowns

2020 ◽  
Vol 14 (02) ◽  
pp. 200-205 ◽  
Author(s):  
Noor Nawafleh ◽  
Abdel Raheem Bibars ◽  
Elina Al Twal ◽  
Andreas Öchsner
Keyword(s):  
Stainless Steel ◽  
Tungsten Carbide ◽  
Fracture Resistance ◽  
Fracture Load ◽  
Control Group ◽  
Chewing Simulation ◽  
Steatite Ceramic ◽  
Computer Aided ◽  
Zirconia Crowns ◽  
The Mean

Abstract Objective This study investigates the influence of the most commonly used indenter materials on fatigue survival and fracture resistance of zirconia crowns. Materials and Methods A total of 40 zirconia crowns were prepared using computer-aided design (CAD)/computer-aided manufacturing (CAM) technology: 30 crowns were divided into three experimental groups of 10 specimens and the last 10 specimens acted as the control group. The experimental groups were subjected to chewing simulation with simultaneous thermocycling. Three indenter materials (steatite ceramic, stainless steel, and tungsten carbide) with identical diameter were used to load the specimens. All crowns were then subjected to single load to fracture test in universal testing machine. Load was applied vertically with a crosshead speed of 1 mm/min until failure, and fracture load was recorded. Statistical Analysis Normal distribution of data was confirmed using the Shapiro–Wilk test. Descriptive statistics including means and standard deviations were determined for all groups. Differences between groups were tested using Dunnett’s test and paired sample t-test. Results Chewing simulation for 1.2 million cycles resulted in 100% survival. The highest mean fracture load was recorded for the control group and the lowest one was for the group fatigued with stainless steel indenter. Chewing simulation statistically significantly (p < 0.05) reduced the mean fracture load of the crowns fatigued with stainless steel and steatite ceramic indenter. However, the mean fracture load for the crowns fatigued with tungsten carbide was not significantly different from that of the control group. Conclusion Steatite ceramic and stainless steel indenters produced close results and significantly reduced fracture load of zirconia crowns. However, tungsten carbide indenter caused nonsignificant reduction in the fracture load of zirconia crowns.

scholarly journals In vitro Simulation of Periodontal Ligament in Fatigue Testing of Dental Crowns

2020 ◽  
Vol 14 (03) ◽  
pp. 380-385
Author(s):  
Noor Nawafleh ◽  
Abdel Raheem Bibars ◽  
Shareen Elshiyab ◽  
Yasmeen Janzeer
Keyword(s):  
Statistical Analysis ◽  
Epoxy Resin ◽  
Periodontal Ligament ◽  
Fatigue Testing ◽  
Fracture Load ◽  
Chewing Simulation ◽  
Mandibular Molar ◽  
Computer Aided ◽  
Zirconia Crowns

Abstract Objective Fatigue testing of restorative material has been appreciated as an appropriate method to evaluate dental restorations. This study aims to investigate the influence of periodontal ligament (PDL) simulation on fatigue and fracture tests results of zirconia crowns. Materials and Methods A standard tooth preparation for all ceramic zirconia crown was made on a typodont mandibular molar. The prepared master die was duplicated using epoxy resin to produce 40 replicas. PDL simulation was made by surrounding the root of 20 dies with a 0.3-mm thick silicon layer. The other 20 specimens had no PDL simulation. Zirconia crowns were fabricated using computer-aided design/computer-aided manufacturing technology and cemented to the epoxy resin dies. Ten crowns from each group were subject to chewing simulation with simultaneous thermocycling (5–55°C). All specimens were then loaded until failure in universal testing machine. Statistical Analysis Statistical analysis was conducted using SPSS software. Shapiro–Wilk test confirmed the normal distribution of data. Descriptive statistic was performed and differences between the groups were analyzed using paired samples t-test. Results All fatigued crowns survived chewing simulation; no failure was observed after finishing simulation. The highest mean fracture load recorded was 3,987 ± 400 N for the no fatigue/no periodontal simulation group. Comparing the mean fracture load of the two groups with periodontal simulation and the two groups with no periodontal simulation showed no statistically significant difference (p > 0.5). Conclusion Considering the testing set-up applied in this study, simulating PDL using resilient materials does not affect the in vitro survival and fracture resistance of zirconia crowns.

scholarly journals COMPARATIVE EVALUATION OF RETENTION AND FRACTURE RESISTANCE OF ENDODONTICALLY TREATED TEETH REINFORCED WITH THREE DIFFERENT POSTS SYSTEMS: AN IN VITRO STUDY

2020 ◽  
pp. 1-3
Author(s):  
Deebah Choudhary
Keyword(s):  
Stainless Steel ◽  
Glass Fiber ◽  
Fracture Resistance ◽  
In Vitro Study ◽  
Fracture Load ◽  
Fiber Post ◽  
Endodontically Treated Teeth ◽  
Glass Fiber Post ◽  
The Mean

Aim: To compare the retention and fracture resistance of three different pre-fabricated posts systems in endodontically treated anterior tooth. Materials and Methods: Root canal treatment was performed for all the 90 samples used in the study. After the completion of obturation, post space preparation was done accompanied by post cementation. The samples were divided into three groups depending on the post cemented (Stainless Steel, Glass fiber and Ceramic post). The samples were first evaluated for retention with a help of a three-jaw chuck, which grasped the post and tried to pull it out. The force required to dislodge each post was recorded in Newtons. To evaluate the fracture resistance, the samples were subjected to compressive loads at an angle. The load required was then recorded in Newtons. Results: The mean retention values for Stainless Steel post were significantly greater than those for Glass fiber post and Ceramic post. The mean retention values of glass-fiber post and ceramic post were not statistically different. The fracture load of the post system, it was revealed that highest mean value was seen in Stainless Steel post and was significant than ceramic post and glass-fiber post. Conclusion: Within the limitation of this study, it can be concluded that the pre-fabricated stainless steel post exhibits a significantly higher fracture resistance and also the retention was more as compared to Glass fiber post and Ceramic post.

scholarly journals Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Restored with Resin Fiber Post and Stainless Steel Post: An In Vitro Study

2015 ◽  
Vol 03 (02) ◽  
pp. 080-084
Author(s):  
Vijay Singh ◽  
Poonam Bogra ◽  
Saurabh Gupta ◽  
Navneet Kukreja ◽  
Neha Gupta
Keyword(s):  
Stainless Steel ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Compressive Force ◽  
Control Group ◽  
Fiber Post ◽  
Endodontically Treated Teeth ◽  
Group I ◽  
Significant Difference

AbstractFracture resistance of endodontically treated teeth restored with post. Aims: This study aims to compare the fracture resistance of endodontically treated teeth restored with resin fiber and stainless steel post. Commercially available prefabricated resin fiber post(Dentsply Maillefer Easy Post), prefabricated stainless steel post(Coltene/Whaledent Parapost) were used. Methods and Material: Forty five maxillary central incisors were obturated and divided into 3 groups: Control Group (Group I) without any post (n = 15), Resin Fiber Post Group (Group II) (n = 15) and Stainless Steel Post Group (Group III) (n = 15). In all Groups except control group, post space was prepared; a post was cemented, and a core build-up was provided. All the specimens were subjected to compressive force under a universal testing machine until fracture. Statistical analysis used: The results were analyzed using the variable analysis test (ANOVA). Results: One-way analysis of variance revealed significant difference among test groups. The control group demonstrated highest fracture resistance (925.2183 N), followed by the resin fiber post group (486.7265 N) and stainless steel post group (423.539N). Conclusions: Teeth restored with resin fiber post showed higher fracture resistance values than prefabricated stainless steel post.

scholarly journals A Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth restored with Composite Resin Core using Two Different Designs of Prefabricated Metal Posts: An in vitro Study

2017 ◽  
Vol 7 (2) ◽  
pp. 97-102
Author(s):  
Sabita M Ram ◽  
Naisargi Shah ◽  
Amit M Gaikwad
Keyword(s):  
Fracture Resistance ◽  
Comparative Evaluation ◽  
Composite Resin ◽  
Fracture Load ◽  
Endodontically Treated Teeth ◽  
Group I ◽  
Resin Core ◽  
Post And Core ◽  
The Mean

ABSTRACT Aim To comparatively evaluate the fracture resistance of endodontically treated teeth restored with light-cured composite resin core using two different designs of prefabricated metal posts. Materials and methods A total of 30 single-rooted anterior teeth were selected for the study and endodontically treated. Teeth were sectioned 2 mm above the cementoenamel junction and were randomly divided into two groups (n = 15). Teeth in group I were restored with Parallel post—EG post and group II with parallel post with coronal flare—i post. Light-cured composite core buildup was done in all samples using a customized core former. Compressive load was applied at a 135° angle to the long axis of the tooth at a cross-head speed of 1 mm/minute until visible signs of fracture were observed. Levene's test and t-test were used to determine the difference of the failure loads between the groups (α = 0.05). Results The mean values (standard deviation [SD]) for fracture resistance were 295.55 N and 469.59 N for parallel post—EG post and parallel post with coronal flare—i post respectively. Since the p-value for the t-test is less than 0.05, it indicates that we should reject null hypothesis and conclude that the mean fracture load of parallel post with coronal flare—i post is significantly more than that of mean fracture load of parallel post—EG post. Conclusion The study conducted evaluated that the fracture resistance of endodontically treated teeth with parallel post with coronal flare—i post and core buildup had better strength as compared with parallel post—EG post and core buildup. Clinical significance The present study will help the clinician to select the appropriate prefabricated metal post that will fit exactly into the coronal flare of the canal improving clinical performance, thus increasing the longevity of the restoration. How to cite this article Gaikwad AM, Shah N, Ram SM. A Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth restored with Composite Resin Core using Two Different Designs of Prefabricated Metal Posts: An in vitro Study. J Contemp Dent 2017;7(2):97-102.

scholarly journals Effect of Reduced Occlusal Thickness with Two Margin Designs on Fracture Resistance of Monolithic Zirconia Crowns

2020 ◽  
Vol 14 (02) ◽  
pp. 245-249
Author(s):  
Haider Hasan Jasim ◽  
Meelad Basil Findakly ◽  
Nada Ali Mahdi ◽  
Mustafa Tariq Mutar
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
Three Dimensional ◽  
Fracture Load ◽  
Anova Test ◽  
Optical Scanner ◽  
Nickel Chromium ◽  
Significant Difference ◽  
Zirconia Crowns ◽  
Monolithic Zirconia

Abstract Objectives The aim of this study was to compare the effects of two margin designs (shoulderless and slight chamfer) with two occlusal thicknesses on fracture resistance and failure mode of the monolithic zirconia crowns. Materials and Methods Forty nickel–chromium dies were duplicated from the previous two prepared teeth using a three-dimensional optical scanner. Nickel–chromium supporting dies were divided into two main groups (n = 20) according to the type of margin design: group A, slight chamfer margin design and group B, shoulderless margin design. These groups were further divided into two subgroups according to the occlusal thicknesses (0.5 and 1 mm). The digital imaging of each die was done using a three-dimensional optical scanner, then zirconia blocks were milled by 5-axis machine. The crowns were cleaned by alcohol, air dried, and cemented by resin cement. Next, the crowns were subjected to 500 hot and cold cycles (30 seconds for each cycle). The samples were subjected to a static load until failure using an electronic universal testing machine and fracture resistance was recorded in Newton (N). Statistical Analysis Data were analyzed using the test of normality (Shapiro–Wilk test) and two-way analysis of variance (ANOVA) test. Results  The highest mean fracture load was recorded by the shoulderless (1 mm occlusal thickness) subgroup (3,992.5 N), followed by shoulderless (0.5 mm occlusal thickness) subgroup (3,244.4 N), and the slight chamfer (1 mm occlusal thickness) subgroup (2,811 N). The lowest mean of fracture load was recorded by slight chamfer (0.5 mm occlusal thickness) subgroup (1,632.9 N). The two-way ANOVA test revealed a significant difference between the four subgroups. Regarding the fracture mode, the slight chamfer subgroups showed a severe fracture of the restoration while the shoulderless subgroups showed a fracture through the midline of the restoration. Conclusion Within the limitation of the comparative study, shoulderless margin design has a more favorable outcome than a slight chamfer design in all thicknesses. Although the restoration with reduced occlusal thickness has lower fracture resistance than 1 mm occlusal thickness, the 0.5 mm restorations still can tolerate occlusal forces.

scholarly journals Fracture Resistance of Monolithic Zirconia Crowns in Implant Prostheses in Patients with Bruxism

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1623 ◽  
Author(s):  
Ting-Hsun Lan ◽  
Chin-Yun Pan ◽  
Pao-Hsin Liu ◽  
Mitch M. C. Chou
Keyword(s):  
Cyclic Loading ◽  
Computer Aided Design ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Von Mises Stress ◽  
High Fracture ◽  
Computer Aided ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
Von Mises

The aim of this study is to determine the minimum required thickness of a monolithic zirconia crown in the mandibular posterior area for patients with bruxism. Forty-nine full zirconia crowns, with seven different occlusal thicknesses of 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mm, were made by using a computer-aided design/computer-aided manufacturing system (CAD/CAM). Seven crowns in each group were subjected to cyclic loading at 800 N and 5 Hz in a servohydraulic testing machine until fracture or completion of 100,000 cycles. Seven finite element models comprising seven different occlusal thicknesses of 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1.0 mm were simulated using three different loads of vertical 800 N, oblique 10 degrees 800 N, and vertical 800 N + x N torque (x = 10, 50, and 100). The results of cyclic loading tests showed that the fracture resistance of the crown was positively associated with thickness. Specimen breakage differed significantly according to the different thicknesses of the prostheses (p < 0.01). Lowest von Mises stress values were determined for prostheses with a minimal thickness of 1.0 mm in different loading directions and with different forces. Zirconia specimens of 1.0 mm thickness had the lowest stress values and high fracture resistance and under 800 N of loading.

scholarly journals Effects of different lingual retainers on periodontal health and stability

2021 ◽  
Author(s):  
Rabia Adanur-Atmaca ◽  
Serpil Çokakoğlu ◽  
Fırat Öztürk
Keyword(s):  
Stainless Steel ◽  
Computer Aided Design ◽  
Steel Wire ◽  
Mean Value ◽  
Periodontal Health ◽  
Anterior Teeth ◽  
Significant Difference ◽  
Computer Aided ◽  
Group 3 ◽  
The Mean

ABSTRACT Objectives To evaluate the effects of different lingual retainers on periodontal health and stability of mandibular anterior teeth at the 1-year follow-up. Materials and Methods One hundred thirty-two patients were randomly allocated to four groups using different lingual retainers: group 1, 0.016 × 0.022-in dead-soft wire; group 2, 0.0215-in 5-strand stainless steel wire; group 3, 0.014 × 0.014-in computer-aided design/computer-aided manufacturing nitinol retainer (Memotain); group 4, connected bonding pads. Plaque, gingival, and calculus indexes were used to evaluate periodontal health, and Little's irregularity index, intercanine width, and arch length measurements were performed to evaluate stability. All measurements were performed at each time point (debonding and 3, 6, 9, and 12 months). Results The mean value of the gingival index obtained in group 3 was lower than the mean value for all other groups. The mean value of the calculus index was the lowest in group 3, and there was a significant difference between group 3 and groups 1 and 2. No differences were found among the groups in terms of plaque index, intercanine width, and arch length. The least irregularity was obtained in groups 2 and 3. There were no significant differences between these groups and groups 1 and 4. Conclusions Gingival inflammation and calculus accumulation were the lowest in group 3 (Memotain). The irregularity for Memotain and stainless steel retainers was less than or the other groups. However, no clinically significant worsening of periodontal health or relapse were seen in any groups after 1 year.

scholarly journals In Vitro Comparison of Marginal and Internal Fit of Zirconia Copings Fabricated by One CAD/CAM System with Two Different Scanners

2021 ◽  
Author(s):  
Zahra Khamverdi1 ◽  
Elmira Najafrad ◽  
Maryam Farhadian
Keyword(s):  
T Test ◽  
Marginal Fit ◽  
Significant Difference ◽  
Computer Aided ◽  
Cad Cam ◽  
Zirconia Crowns ◽  
Monolithic Zirconia ◽  
The Mean ◽  
Internal Fit ◽  
Paired T Test

Objectives: Marginal and internal fit of restorations are two important clinical factors for assessing the quality and durability of computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated monolithic zirconia restorations. The purpose of this study was to evaluate the marginal and internal fit of CAD/CAM zirconia crowns with two different scanners (i3D scanner and 3Shape D700). Materials and Methods: Twelve extracted sound human posterior teeth were prepared for full zirconia crowns. Two different extraoral scanners namely i3D scanner and 3Shape D700 were used to digitize type IV gypsum casts poured from impressions. The crowns were milled from presintered monolithic zirconia blocks by a 5-axis milling machine. The replica technique and MIP4 microscopic image analysis software were utilized to measure the marginal and internal fit by a stereomicroscope at ×40 magnification. The collected data were analyzed by paired t-test. Results: The mean marginal gap was 203.62 μm with 3Shape D700 scanner and 241.07 μm with i3D scanner. The mean internal gap was 192.30 μm with 3Shape D700 scanner and 196.06 μm with i3D scanner. The results of paired t-test indicated that there was a statistically significant difference between the two scanners in marginal fit (P=0.04); while, there was no statistically significant difference in internal fit (P=0.761). Conclusion: Within the limitations of this study, the results showed that type of extraoral scanner affected the marginal fit of CAD/CAM fabricated crowns; however, it did not have a significant effect on their internal fit.

scholarly journals Effect of Passive Ultrasonic Irrigation on Apical Extrusion of Irrigating Solution

2008 ◽  
Vol 02 (03) ◽  
pp. 198-203 ◽  
Author(s):  
Tamer Tasdemir ◽  
Kursat Er ◽  
Davut Celik ◽  
Tahsin Yildirim
Keyword(s):  
Stainless Steel ◽  
Sodium Hypochlorite ◽  
Root Canal ◽  
Control Group ◽  
Passive Ultrasonic Irrigation ◽  
Root Canals ◽  
Apical Extrusion ◽  
Ultrasonic Irrigation ◽  
The Mean ◽  
Mandibular Incisors

ABSTRACTObjectives: To determine the influence of passive ultrasonic irrigation (PUI) on apical extrusion of irrigating solution.Methods: Twenty freshly extracted maxillary and mandibular incisors with single straight root canals were instrumented with ProTaper rotary files. During final irrigation, the root canals were filled with 2.5% sodium hypochlorite (NaOCl) solution and PUI was performed with a piezoelectronic unit. A stainless steel instrument (size 15) was inserted into the root canal and the irrigant was ultrasonically activated for one minute. This sequence was repeated three times, resultingin a total PUI time of three minutes. The volume of extruded irrigant was measured by Pipetman pipettes. The data were statistically analyzed with the Mann-Whitney U test.Results: The mean volume of apical extruded irrigant was 2.15 �L for the PUI group and 14 �L forthe control group. The experimentalgroup extruded significantly smaller amounts of irrigant than the control group (P<.05).Conclusions: The PUI procedure as a final irrigation was associated with less apical extrusion of the irrigating solution. (Eur J Dent 2008;2:198-203)

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