scholarly journals Influence of CAD/CAM Material and Preparation Design on the Long-term Fracture Resistance of Endocrowns Restoring Maxillary Premolars

2020 ◽  
Vol 23 (4) ◽  
pp. 9p
Author(s):  
Ahmed Mohsen Foad ◽  
Amina Hamdy ◽  
Ghada Abd el Fatah ◽  
Ahmad Aboelfadl
Keyword(s):  
Fracture Resistance ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Ceramic Materials ◽  
Cyclic Fatigue ◽  
Butt Joint ◽  
Significance Level ◽  
Cad Cam ◽  
Maxillary Premolars

Objective: To evaluate the effect of different occlusal preparation designs and CAD/CAM materials on the fracture resistance of maxillary premolars endcrowns. Materials and Methods: sixty-four endodontically treated upper first premolars were randomly divided into four groups according to ceramic materials (Vita Enamic and IPS emax CAD) and occlusal preparation designs (Anatomical and horizontal butt joint). After teeth preparation, the restorations were all made by CAD/CAM system (Cerec MCXL). Half of each group had undergone cyclic fatigue testing of 105 cycles with 50N loading force at a frequency of 0.5Hz in a mechatronic chewing simulator machine, and then all samples were loaded to fracture using a universal testing machine with a cross head speed of 0.5mm/min recording the fracture resistance values in N . The specimens were measured and statistically analyzed using using three-way analyses of variance (ANOVA), followed by serial two-way and one-way ANOVAs at each level of the study. P-values were adjusted for multiple comparisons using BENFORRONI correction and the significance level was set at P ? 0.05 for all tests. Results: Vita Enamic endocrowns showed higher fracture resistance values than IPS e max specimens. Conclusions: Vita Enamic endocrowns with anatomical preparations were found to be more favourable restoring endodontically treated maxillary premolars. KEYWORDSEndocrowns; All-Ceramic; Fracture; Cyclic loading; CAD/CAM

scholarly journals Effect of Incisal Porcelain Veneering Thickness on the Fracture Resistance of CAD/CAM Zirconia All-Ceramic Anterior Crowns

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Noha Badran ◽  
Sanaa Abdel Kader ◽  
Fayza Alabbassy
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
Mode Iii ◽  
Nickel Chromium ◽  
Significant Difference ◽  
All Ceramic ◽  
Metal Ceramic ◽  
Cad Cam ◽  
Ceramic Crown

Statement of Problem. In some clinical situations, the vertical length of either a prepared tooth or an implant abutment is short, while the occlusal clearance to be restored by a porcelain crown is large. Incisal thickness of the veneering porcelain should be considered to prevent mechanical failure of the crown. Purpose. The aim of this study is to evaluate the effect of two different incisal veneering porcelain thickness on the fracture resistance of the anterior all-ceramic CAD/CAM zirconia crown system as compared with the conventionally used metal ceramic crown system. Method. CAD/CAM zirconia all-ceramic and metal ceramic crowns were fabricated on the prepared dies with standardized dimensions and designs using standardized methods according to the manufacturer’s instructions. All crowns were then adhesively luted with resin-based cement (Multilink cement system), subjected to thermal cycling and cyclic loading, and were loaded until fracture using the universal testing machine to indicate the fracture resistance for each crown material in each veneering thickness. Results. Statistical analysis was carried out, and the results showed that the fracture resistance of the nickel-chromium metal ceramic group was significantly higher than that of the CAD/CAM zirconia all-ceramic group. Also, the fracture resistance of crowns with 1.5 mm incisal veneering thickness was significantly higher than those with 3 mm incisal veneering thickness in both groups. Furthermore, there was no significant difference in the fracture mode of the two groups where 50% of the total specimens demonstrated Mode II (veneer chipping), while 35% demonstrated Mode I (visible crack) and only 15% demonstrated Mode III (bulk fracture). Conclusion. High failure load values were demonstrated by the specimens in this study, which suggest sufficient strength of both incisal veneering thickness in both crown systems to withstand clinical applications; however, the fracture patterns still underline the requirement of a core design that support a consistent thickness of the veneering ceramic, and it is recommended to conduct long-term prospective clinical studies to confirm findings reported in the present study.

scholarly journals Fracture load of nano-ceramic composite material for anterior endocrown restorations

2020 ◽  
Vol 23 (1) ◽  
Author(s):  
Salma Alghalayini ◽  
Kamal Khaled Ebeid ◽  
Ayman Aldahrab ◽  
Marwa Wahsh
Keyword(s):  
Ceramic Composite ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Cyclic Fatigue ◽  
Fracture Load ◽  
Endodontically Treated Teeth ◽  
Ceramic Fracture ◽  
Tooth Structure ◽  
All Ceramic ◽  
Cad Cam

Objective: To evaluate ability of Nano Ceramic Composite endocrown to withstand occlusal forces when used in the anterior region. Material and Methods: Eighty endodontically treated maxillary central incisors teeth were randomly divided into two main groups according to the restoration type.  40 of these teeth were post, core and crown restorations and 40 were endocrown restorations.  Then they were divided by halves into two subgroups according to the material used 20 were made with Lava Ultimate and the other 20 with IPS e.max. Each subgroup was then further subdivided into two divisions according to the remaining tooth structure above the CEJ (n=10): 2 mm and 0.5 mm above the CEJ. After teeth preparation, the restorations were all made by CAD/CAM system (Cerec MCXL). All samples had undergone cyclic fatigue testing, and then loaded to fracture using a universal testing machine. The specimens were measured and statistically analyzed using Mann-Whitney test for comparing the mean changes between the groups. Results:  Lava Ultimate showed higher mean fracture load values than IPS e.max specimens. Conclusion: Endocrowns were found to be more favorable when used on endodontically treated teeth than the conventional post, core and crown restorations.KEYWORDSEndocrowns; All-ceramic; Fracture; Cyclic loading.

Structural Integrity Evaluation of Large MOD Restorations Fabricated With a Bulk-Fill and a CAD/CAM Resin Composite Material

2019 ◽  
Vol 44 (3) ◽  
pp. 312-321 ◽  
Author(s):  
C Papadopoulos ◽  
D Dionysopoulos ◽  
K Tolidis ◽  
P Kouros ◽  
E Koliniotou-Koumpia ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Fracture Resistance ◽  
Structural Integrity ◽  
Resin Composite ◽  
Testing Machine ◽  
Fracture Load ◽  
Chi Square ◽  
Significance Level ◽  
Computer Aided ◽  
Cad Cam

SUMMARY Aims: To evaluate the effect of two composite restorative techniques (direct bulk fill vs indirect CAD/CAM) on the fracture resistance and mode of fracture of extended mesio-occlusal-distal (MOD) cavity preparations. Methods: Fifty-one sound human mandibular third molars were divided into three groups (n=17). Extended bucco-lingual MOD cavities were prepared. Teeth in group 1 were restored with a bulk-fill resin composite (Filtek Bulk-Fill Posterior Restorative), teeth in group 2 were restored with composite computer-aided design/computer-aided manufacturing (CAD/CAM) inlays (Lava Ultimate), and teeth in group 3 served as control and remained intact. All specimens were submitted to thermocycling, and a fracture resistance test was performed using a Universal testing machine (0.5 mm/min). Mode of fracture was classified into five types. One-way analysis of variance and the Duncan test were used to analyze the fracture load data at a significance level of α = 0.05. A chi-square test was used for the analysis of fracture mode between the restorative groups. Results: Statistical analysis showed significant differences in fracture resistance among the experimental groups. The teeth restored with the bulk-fill composite exhibited lower fracture resistance (1285.3±655.0 N) when compared to the teeth restored with the composite CAD/CAM inlays (1869.8±529.4 N) (p<0.05). Mode of fracture showed the same distribution between the restorative groups. Conclusions: Although both types of restorations failed at loads larger than those found in the oral cavity, the CAD/CAM composite inlays increased the fracture resistance of teeth with large MOD cavities when compared to direct bulk-fill composite restorations. The majority of fracture types were intraorally repairable for both restorative techniques.

Surface Roughness of Two CAD/CAM Restorative Materials as Affected by Chewing Simulation v1

2022 ◽  
Author(s):  
eaeldwakhly not provided
Keyword(s):  
Surface Roughness ◽  
Computer Aided Design ◽  
Surface Characteristics ◽  
Ceramic Materials ◽  
Study Groups ◽  
Significance Level ◽  
Chewing Simulation ◽  
Computer Aided ◽  
Cad Cam ◽  
The Individual

This study was conducted to assess the surface characteristics in terms of roughness of two CAD/CAM (Computer-Aided-Design/Computer-Aided Manufacturing)restorative material spre and post chewing simulation exposure. Methods: Specimens were prepared from two CAD/CAM ceramic materials: Cerec Blocs C and IPS e-max ZirCAD. A total of 10 disks were prepared for each study group. 3D optical noncontact surface profiler was used to test the surface roughness (ContourGT, Bruker, Campbell, CA, USA). A silicone mold was used to fix the individual samples using a self-curing resin. Surface roughness (SR) was examined pre and post exposure to chewing simulation. 480,000 simulated chewing cycles were conducted to mimic roughly two years of intraoral clinical service. The results data was first tested for normality and equal variance (Levene’s test >0.05) then examined with paired and independent sample t-test at a significance level of (p < 0.05). Results:The two CAD-CAM materials tested exhibited increased surface roughness from baseline. The highest mean surface roughness was observed in Cerec blocs C group after chewing simulation (2.34 µm± 0.62 µm). Whereas the lowest surface roughness was observed in IPS e.max ZirCAD group before chewing simulation (0.42 µm± 0.16 µm). Both study groups exhibited significantly different surface roughness values (p< 0.05). There was a statistically higher surface roughness values after the chewing simulation in Cerec blocs C when compared to IPS e.max ZirCAD groups (p = 0.000).Conclusion:Even though both tested CAD/CAM materials differ in recorded surface roughness values, results were within clinically accepted values.

scholarly journals Fracture Resistance in Non-Vital Teeth: Absence of Interproximal Ferrule and Influence of Preparation Depth in CAD/CAM Endocrown Overlays—An In Vitro Study

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 436
Author(s):  
Lucía Barallat ◽  
María Arregui ◽  
Sandra Fernandez-Villar ◽  
Blanca Paniagua ◽  
Andrés Pascual-La Rocca
Keyword(s):  
Fracture Strength ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Compressive Force ◽  
Ample Evidence ◽  
Alveolar Crest ◽  
Cad Cam ◽  
Group A ◽  
Group B ◽  
Group D

There is ample evidence to support the use of endocrowns to restore endodontic teeth. However, the influence of the position of the interproximal margins on fracture strength has not yet been studied. The aim was to determine the relationship between the apicocoronal position of the interproximal restorative margins and fracture resistance in nonvital teeth restored with CAD/CAM endocrown overlays. Forty extracted human maxillary premolars were prepared for endocrown overlay restorations without ferrule on the interproximal aspects and classified according to the position of the interproximal restoration margins in relation to the alveolar crest: 2 mm (group A), 1 mm (group B), 0.5 mm (group C), and 0 mm (group D). Fracture strength was measured using a universal testing machine applying a compressive force to the longitudinal tooth axis. Group A had a mean fracture resistance of 859.61 (±267.951) N, group B 1053.9 (±333.985) N, group C 1124.6 (±291.172) N, and group D 780.67 (±183.269) N, with statistical differences between groups. Group C had the highest values for fracture strength compared to the other groups (p < 0.05). The location of the interproximal margins appears to influence the fracture resistance of CAD/CAM endocrown overlays. A distance of 0.5 mm between the interproximal margin and the alveolar crest was associated with increased fracture resistance.

scholarly journals Fracture Resistance and Microleakage of Endocrowns Utilizing Three CAD-CAM Blocks

2015 ◽  
Vol 40 (2) ◽  
pp. 201-210 ◽  
Author(s):  
HM El-Damanhoury ◽  
RN Haj-Ali ◽  
JA Platt
Keyword(s):  
Fracture Mode ◽  
Computer Aided Design ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Resin Cement ◽  
Blue Dye ◽  
Endodontically Treated Teeth ◽  
Modes Of Failure ◽  
Computer Aided ◽  
Cad Cam

SUMMARY This study assessed marginal leakage and fracture resistance of computer-aided design/computer-aided manufacturing (CAD/CAM) fabricated ceramic crowns with intracoronal extensions into the pulp chambers of endodontically treated teeth (endocrowns) using either feldspathic porcelain (CEREC Blocks [CB], Sirona Dental Systems GmbH, Bensheim, Germany), lithium disilicate (e.max [EX], Ivoclar Vivadent, Schaan, Liechtenstein), or resin nanoceramic (Lava Ultimate [LU], 3M ESPE, St Paul, MN, USA).). Thirty extracted human permanent maxillary molars were endodontically treated. Standardized preparations were done with 2-mm intracoronal extensions of the endocrowns into the pulp chamber. Teeth were divided into three groups (n=10); each group was restored with standardized CAD/CAM fabricated endocrowns using one of the three tested materials. After cementation with resin cement, specimens were stored in distilled water at 37°C for one week, subjected to thermocycling, and immersed in a 5% methylene-blue dye solution for 24 hours. A compressive load was applied at 35 degrees to long axis of the teeth using a universal testing machine until failure. Failure load was recorded, and specimens were examined under a stereomicroscope for modes of failure and microleakage. Results were analyzed using one-way analysis of variance and Bonferroni post hoc multiple comparison tests (α=0.05). LU showed significantly (p&lt;0.05) higher fracture resistance and more favorable fracture mode (ie, fracture of the endocrown without fracture of tooth) as well as higher dye penetration than CB and EX. In conclusion, although using resin nanoceramic blocks for fabrication of endocrowns may result in better fracture resistance and a more favorable fracture mode than other investigated ceramic blocks, more microleakage may be expected with this material.

Effect of Extended Aging on Asphalt Materials Containing Re-Refined Engine Oil Bottoms

2017 ◽  
Vol 2632 (1) ◽  
pp. 60-69 ◽  
Author(s):  
David J. Mensching ◽  
Adrian Andriescu ◽  
Christopher DeCarlo ◽  
Xinjun Li ◽  
Jack S. Youtcheff
Keyword(s):  
Low Temperature ◽  
Fatigue Testing ◽  
Asphalt Mixture ◽  
Field Performance ◽  
Cyclic Fatigue ◽  
Engine Oil ◽  
Short Term ◽  
Bending Beam Rheometer ◽  
The Difference

The use of re-refined engine oil bottoms (REOBs) in asphalt pavements is a topic of much debate because the aging susceptibility and quantity of the additive in the binder may affect field performance. In this study, four mixtures with varying REOB contents (up to 15%) were long-term oven aged by using a high-temperature, short-duration method (135°C, 24 h) and compared with existing data on mixtures aged with more conventional short-term and long-term oven-aging procedures. The recovered binders underwent Superpave® grading, double-edge notched tension, and extended bending beam rheometer testing, and the binders were subjected to dynamic modulus, cyclic fatigue testing in the asphalt mixture performance tester, and thermal stress restrained specimen testing. Results showed a general insensitivity when short-term oven-aged (135°C, 4 h) materials were compared with long-term oven-aged (85°C, 5 days) materials, whereas the aging process at 135°C over 24 h resulted in substantial changes to the stiffness and relaxation properties across high-, intermediate-, and low-temperature modes. The difference between the stiffness-based and slope-based low-temperature performance grades appears to be an indicator for REOB modification, with the test for physical hardening of the binder being more sensitive than standard bending beam rheometer testing. The details in this paper provide information for the asphalt pavement community to consider as specifications. Standard practices are developed to address REOB modification.

scholarly journals Original vs Non-Original “Cast-To” Gold Abutment-Implant Connection: Analysis of the Internal Fit and Long-Term Fatigue Performance

2020 ◽  
Author(s):  
Raquel Alonso-Pérez ◽  
José F. Bartolomé ◽  
Cristina Fraile ◽  
Guillermo Pradíes
Keyword(s):  
Artificial Saliva ◽  
Testing Machine ◽  
Cyclic Fatigue ◽  
Fatigue Performance ◽  
Tight Contact ◽  
Implant Abutment ◽  
Implant System ◽  
Internal Fit

Abstract Background: Restoring implants with not original abutment-implant connection are widely used by clinicians. Due to the current scarcity of in-vitro studies about compatible abutments and lack of relevant clinical studies, long-term fatigue performance of non-original abutments should be analyzed. The aim of this research was to assess the internal accuracy and the cyclic fatigue life after artificial aging of three implant-abutment configurations restored with one original and two compatible non-original “cast-to” gold abutments.Materials and Methods: Forty-eight original internal hexagon connection implants were connected to three different brands of abutments (n= 16 each): one original to the implant system and two non-originals. Internal accuracy and the percentage of surface with tight contact were assessed under Scanning Electron Microscope (SEM) in twelve cross-sectioned samples at three different areas (platform, internal and screw). To evaluate the fatigue mechanical behaviour under cyclic load, samples were loaded according to the ISO Norm 14801 in a universal testing machine at 2 Hz in air. Previously, samples were aged by thermocycling with 10,000 cycles at 5 °C and 55 °C in artificial saliva. Results: Original abutments presented the best accuracy and highest percentage of tight contact in the internal areas. Meanwhile, original abutments showed the lower cyclic fatigue strength degradation and the long-term success. Conclusions: Occlusal loads are transferred more homogenously through the system when original abutments are used because the better fit between the different internal components. This fact provides the highest fatigue resistance for all the restorations studied.

Fracture resistance of endodontically treated maxillary premolars restored with CAD/CAM ceramic inlays

2005 ◽  
Vol 94 (4) ◽  
pp. 342-349 ◽  
Author(s):  
Christian Hannig ◽  
Christoph Westphal ◽  
Klaus Becker ◽  
Thomas Attin
Keyword(s):  
Fracture Resistance ◽  
Ceramic Inlays ◽  
Cad Cam ◽  
Maxillary Premolars
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