scholarly journals Effect of Die Spacer Thickness on the Microshear Bond Strength of CAD/CAM Lithium Disilicate Veneers

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Sherine Mohamed Farag ◽  
Mona Mohamed Ghoneim ◽  
Rania Reda Afifi
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Lithium Disilicate ◽  
Chi Square ◽  
Cad Cam ◽  
Chi Square Test ◽  
Group B ◽  
Post Hoc ◽  
Microshear Bond Strength ◽  
Die Spacer

Aim. The aim of this study was to compare the microshear bond strength of ceramic veneers with digital die spacer settings at 20, 40, and 100 µm. Materials and Methods. Eighteen milled lithium disilicate microdiscs (IPS e.max CAD, Ivoclar Vivadent) were divided into three groups (n = 6) according to their digital die spacer settings: group A = 20 µm, group B = 40 µm, and group C = 100 µm. Six randomly selected sound maxillary premolars received three microdiscs each. Each microdisc was 1 mm in diameter and 1 mm in height. The buccal surfaces of the premolars were prepared with a 0.5 mm depth in enamel. After cementation, the specimens were thermocycled for 2,500 cycles between 5 and 55°C. Microshear bond strength testing was performed using a universal testing machine until bonding failure. Failure modes were evaluated using a stereomicroscope. Statistical analyses included one-way ANOVA, Tukey’s post hoc test, and chi-square test with a 5% alpha error and 80% study power. Results. The mean microshear bond strength values were calculated in MPa for group A = 31.91 ± 12.41, group B = 29.58 ± 5.03, and group C = 13.85 ± 4.12. One-way ANOVA ( p ≤ 0.05 ) showed a statistically significant difference in microshear bond strength among the three groups. Tukey’s post hoc test showed significant differences between groups A and C ( p = 0.004 ) and between groups B and C ( p = 0.011 ). The failure modes were presented as cohesive, adhesive, and mixed failures. Chi-square test indicated that the failure mode distribution was not significantly different among the three groups ( p = 0.970 ). Conclusion. Higher digital die spacer settings decrease the microshear bond strength of CAD/CAM lithium disilicate veneers.

scholarly journals The Effects of Cavity Preparation and Composite Resin on Bond Strength and Stress Distribution Using the Microtensile Bond Test

2018 ◽  
Vol 43 (1) ◽  
pp. 81-89 ◽  
Author(s):  
SSL Braga ◽  
LRS Oliveira ◽  
RB Rodrigues ◽  
AA Bicalho ◽  
VR Novais ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Bond Strength ◽  
Failure Modes ◽  
Composite Resin ◽  
Shrinkage Stress ◽  
Cavity Preparation ◽  
Chi Square ◽  
Chi Square Test ◽  
Post Hoc ◽  
Made In

SUMMARY Objectives: To evaluate the effect of flowable bulk-fill or conventional composite resin on bond strength and stress distribution in flat or mesio-occlusal-distal (MOD) cavity preparations using the microtensile bond strength (μTBS) test. Methods: Forty human molars were divided into two groups and received either standardized MOD or flat cavity preparations. Restorations were made using the conventional composite resin Z350 (Filtek Z350XT, 3M-ESPE, St Paul, MN, USA) or flowable bulk-fill (FBF) composite resin (Filtek Bulk Fill Flowable, 3M-ESPE). Postgel shrinkage was measured using the strain gauge technique (n=10). The Z350 buildup was made in two increments of 2.0 mm, and the FBF was made in a single increment of 4.0 mm. Six rectangular sticks were obtained for each tooth, and each section was used for μTBS testing at 1.0 mm/min. Polymerization shrinkage was modeled using postgel shrinkage data. The μTBS data were analyzed statistically using a two-way analysis of variance (ANOVA), and the postgel shrinkage data were analyzed using a one-way ANOVA with Tukey post hoc test. The failure modes were analyzed using a chi-square test (α=0.05). Results: Our results show that both the type of cavity preparation and the composite resin used affect the bond strength and stress distribution. The Z350 composite resin had a higher postgel shrinkage than the FBF composite resin. The μTBS of the MOD preparation was influenced by the type of composite resin used. Irrespective of composite resin, flat cavity preparations resulted in higher μTBS than MOD preparations (p<0.001). Specifically, in flat-prepared cavities, FBF composite resin had a similar μTBS relative to Z350 composite resin. However, in MOD-prepared cavities, those with FBF composite resin had higher μTBS values than those with Z350 composite resin. Adhesive failure was prevalent for all tested groups. The MOD preparation resulted in higher shrinkage stress than the flat preparation, irrespective of composite resin. For MOD-prepared cavities, FBF composite resin resulted in lower stress than Z350 composite resin. However, no differences were found for flat-prepared cavities. Conclusions: FBF composite resin had lower shrinkage stress than Z350 conventional composite resin. The μTBS of the MOD preparation was influenced by the composite resin type. Flat cavity preparations had no influence on stress and μTBS. However, for MOD preparation, composite resin with higher shrinkage stress resulted in lower μTBS values.

scholarly journals Long-term influence of associating an antibacterial agent with GIC on bond strength to caries-affected dentin

2017 ◽  
Vol 16 ◽  
pp. 1-10
Author(s):  
Ana Carolina de Oliveira Becci ◽  
Luana Mafra Marti ◽  
Angela Cristina Cilense Zuanon ◽  
Fernanda Lourenção Brighenti ◽  
Elisa Maria Aparecida Giro
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Multiple Comparisons ◽  
The Other ◽  
Chi Square ◽  
Chi Square Test ◽  
Term Evaluation ◽  
Storage Methods ◽  
Microshear Bond Strength

Aim: To evaluate the bond strength of a GIC associated with chlorhexidine (CHX) to sound and caries-affected dentin, immediately and after six months of storage. Methods: Sixty molars were assigned to two groups of 30 teeth. One had flat dentin surfaces produced and submitted to caries induction to obtain a caries-affected dentin.  In the other group dentin was maintained sound. Teeth of each group were randomly reassigned to three subgroups (n=10) according to the concentration of CHX added to the GIC (0%, 1% and 2% by weight).  Two specimens (1mm diameter x 1 mm high) of the same material were constructed on each dentin surface. One was submitted to the microshear bond strength (µSBS) test after 24 hours and the other after 6 months of storage in water at 37oC. Failure modes were analyzed under a stereomicroscope. Bond strength data were analyzed by three-way ANOVA followed by Games-Howell tests for multiple comparisons, and failure modes by the Chi-square test (α = 0.05). Results: The µSBS values obtained to sound dentin were higher compared with those to caries-affected dentin (p≤0.001). In sound dentin, the group with 2% CHX showed lower  µSBS values compared with 0% and 1% CHX after 24 hours (p=0.005 and p=0.032 respectively). In caries-affected dentin, after 24 hours, µSBS in group with 1% CHX was statistically higher than the values in groups with 2% CHX after 24 hours (p=0.001) and 1% CHX after 6 months (p=0.024). Irrespective of the condition of substrate, comparisons showed no statistically significant differences between the other groups (p≥0.053). Cohesive in material and mixed failures prevailed for all groups. Conclusions: The addition of CHX at concentrations of up to 2% to the GIC did not affect the bond strength of the material to sound and caries-affected dentin in a long-term evaluation.

scholarly journals Evaluation of the bond strength of root-end placed mineral trioxide aggregate and Biodentine in the absence/presence of blood contamination

2016 ◽  
Vol 10 (03) ◽  
pp. 370-375 ◽  
Author(s):  
Huseyin Akcay ◽  
Hakan Arslan ◽  
Merve Akcay ◽  
Merve Mese ◽  
Naciye Nur Sahin
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Mineral Trioxide Aggregate ◽  
Storage Condition ◽  
Filling Material ◽  
Blood Contamination ◽  
Chi Square ◽  
Filling Materials ◽  
Chi Square Test ◽  
Post Hoc

ABSTRACT Objective: Mineral trioxide aggregate (MTA) has been accepted as an appropriate root-end filling material in endodontic microsurgery because of setting ability in the wet environment. The aim of this study was to assess the bond strength of root-end placed MTA and Biodentine (Septodont, Saint Maur des Fossés, France) in the absence/presence of blood contamination. Materials and Methods: Forty-eight single-rooted maxillary incisors were used. subsequent to root-end resection and apical preparation using ultrasonic retro-tips, the specimens were randomly separated into two groups according to the root-end filling materials: MTA (Cerkamed Medical Company, Stalowa, Poland) or Biodentine. The specimens were then separated into two subgroups according to storage condition (absence/presence of blood) (n = 12). After obtaining 2.0 ± 0.1 mm slices, push-out tests were performed. Each slice was examined under a stereomicroscope to evaluate the failure mode. The data were analyzed using two-way analysis of variance and Tukey's post hoc test for multiple comparisons. The failure modes were analyzed using the Chi-square test (P = 0.05). Results: The bond strength was significantly affected by the presence of blood contamination and root-end filling material type (P < 0.001). Biodentine had better bond strength than MTA (P < 0.001). The most common failure type was adhesive failure. According to the Chi-square test, there were no statistically significant differences among the groups (P = 0.394). Conclusions: Biodentine had better bond strength values compared to MTA, and the bond strength of both MTA and Biodentine as root-end filling materials was negatively affected by the presence of blood.

scholarly journals Effect of Two Microshear Test Devices on Bond Strength and Fracture Pattern in Primary Teeth

2013 ◽  
Vol 24 (6) ◽  
pp. 605-609 ◽  
Author(s):  
Tamara Kerber Tedesco ◽  
Eugenio Jose Garcia ◽  
Fabio Zovico Maxnuck Soares ◽  
Rachel de Oliveira Rocha ◽  
Rosa Helena Miranda Grande
Keyword(s):  
Bond Strength ◽  
Failure Mode ◽  
Failure Modes ◽  
In Vitro Study ◽  
Adhesive System ◽  
Fracture Pattern ◽  
Chi Square ◽  
Etch And Rinse ◽  
Chi Square Test

This in vitro study evaluated the influence of two devices for application of shear load in microshear tests on bond strength and fracture pattern of primary enamel and dentin. Eighty primary molars were selected and flat enamel (40 teeth sectioned mesio-distally) and dentin (40 teeth sectioned transversally) surfaces were obtained. Both surfaces were polished to standardize the smear layer. Two-step etch-and-rinse adhesive systems (Adper Single Bond and XP Bond) were used. Polyethylene tubes was placed over the bonded surfaces and filled with composite resin. The microshear testing was performed after storage in water (24 h/37 °C) using two devices for application of microshear loads: a notched rod (Bisco Shear Bond Tester) or a knife edge (Kratos Industrial Equipment). Failure modes were evaluated using a stereomicroscope. Bond strength data were subjected to ANOVA and chi-square test to compare the failure mode distributions (α=0.05). No significant differences were observed between the groups for dentin and enamel bond strength or fracture patterns (p>0.05). The predominant failure mode was adhesive/mixed. In conclusion, the devices for application of shear loads did not influence the bond strength values, regardless of adhesive system and substrate.

scholarly journals In Vitro Fracture Strength of Teeth Restored with Lithium Disilicate Onlays with and without Fiber Post Build-Up

2018 ◽  
Vol 6 (3) ◽  
pp. 35 ◽  
Author(s):  
Nicola Mobilio ◽  
Alberto Fasiol ◽  
Francesco Mollica ◽  
Santo Catapano
Keyword(s):  
Fracture Strength ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Lithium Disilicate ◽  
Fiber Post ◽  
Chi Square ◽  
Human Teeth ◽  
Group A ◽  
Group B

To our knowledge there is no data about the mechanical performance of indirect restoration adhesively cemented on teeth without an adequate build-up to provide the correct geometrical configuration. The aim of this study was to compare the fracture strength of human teeth restored with lithium disilicate onlays, with and without fiber post build-up. Methods: Twenty human mandibular molars were horizontally sectioned and divided into two groups (n = 10). No treatment was applied in group A. Teeth in group B were endodontically treated, built-up using fiber post and composite core and prepared with a circumferential chamfer providing a 1 mm circumferential ferrule. Lithium disilicate onlays were pressed and luted on teeth using dual-curing luting composite. Teeth were tested under static load. Failures were classified as restorable or not restorable. Failure loads were analyzed with one-way analysis of variance. Failure modes were compared using Pearson’s Chi-square tests. Results: The mean fracture loads were 1383.5 N for group A and 1286.3 N for group B. No difference was found (p = 0.6). Ninety per cent of fractures were classified as not restorable in both groups, with no difference (p = 0.8). Conclusions: For teeth restored with adhesive procedures and lithium disilicate onlays, the presence of build-up with fiber post to provide retention and resistance form does not influence the fracture strength.

scholarly journals Effect of two processing techniques used to manufacture lithium disilicate ceramics on the degree of conversion and microshear bond strength of resin cement.

2020 ◽  
Vol 33 (2) ◽  
pp. 98-103
Author(s):  
Amauri Drumond ◽  
Eloisa Paloco ◽  
Sandrine Berger ◽  
Alejandra González ◽  
Artur Carreira ◽  
...  
Keyword(s):  
Bond Strength ◽  
Lithium Disilicate ◽  
Degree Of Conversion ◽  
Resin Cement ◽  
Ceramic Processing ◽  
The Press ◽  
Cad Cam ◽  
Student’S T ◽  
Processing Techniques ◽  
Microshear Bond Strength

The aim of the current study was to compare the effect of two lithium disilicate ceramic processing techniques (pressing and CAD/CAM) on the degree of conversion of resin cement when it is photoactivated and the microshear bond strength of resin cement to ceramics. Two ceramic discs were manufactured: one by the Press technique and another by CAD/CAM technique. Five Variolink Veneer resin cement samples were photoactivated through each ceramic disc and subjected to attenuated total reflectance Fourier transform infrared spectroscopy to evaluate their degree of conversion. To evaluate microshear bond strength, 20 ceramic bars were prepared: 10 using the Press technique and 10 using the CAD/CAM technique. The bars were air abraded with 50-μm Al2O3 particles, treated with 10% hydrofluoric acid for 20 s and subjected to RelyX Ceramic Primer application. Adper Scotchbond Multi-Purpose Adhesive was applied to the bars and cured for 10 s. Two 1-mm-height plastic tubes were placed on each bar and filled with Variolink Veneer resin cement. Each cylinder was cured for 20 s. Then the plastic tubes were removed and the microshear bond strength of each cylinder was tested. Data for degree of conversion (%) and microshear bond strength (MPa) were subjected to Student's t-test (α = 0.05). Both degree of conversion of resin cement photoactivated through ceramic and microshear bond strength of resin cement to ceramic were statistically higher in the group in which ceramic was prepared by CAD/CAM technique (44.74% and 22.18 MPa) than in the group in which the ceramic was prepared by the Press technique (25.71% and 19.83 MPa). The lithium disilicate ceramic processing techniques affected the degree of conversion of resin cement when it is photoactivated through the ceramics and the microshear bond strength of resin cement to ceramics.

Evaluation of bond strength of dual resin cements to CAD/CAM-created lithium disilicate ceramic

2020 ◽  
Vol 69 (3) ◽  
Author(s):  
Felipe Sczepanski ◽  
Cláudia R. Brunnquell ◽  
Sandrine B. Berger ◽  
Eloisa A. Paloco ◽  
Murilo B. Lopes ◽  
...  
Keyword(s):  
Bond Strength ◽  
Lithium Disilicate ◽  
Resin Cements ◽  
Cad Cam

Does a Self-etching Ceramic Primer Improve Bonding to Lithium Disilicate Ceramics? Bond Strengths and FESEM Analyses

2019 ◽  
Vol 44 (2) ◽  
pp. 210-218 ◽  
Author(s):  
GC Lopes ◽  
J Perdigão ◽  
D Baptista ◽  
A Ballarin
Keyword(s):  
Failure Mode ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Control Group ◽  
Shear Mode ◽  
Bond Strengths ◽  
Post Hoc ◽  
Microshear Bond Strength ◽  
And Control ◽  
Silane Solution

SUMMARY Objective: To compare the effect of hydrofluoric acid (HF) vs self-etching ceramic primer on resin cement microshear bond strength (μSBS) and ultramorphology of lithium disilicate (LD) ceramic. Methods and Materials: LD (IPS e.max CAD, Ivoclar Vivadent) blocks (14×4×2 mm3) were polished to 1200 grit and assigned to nine groups (n=5): CON: control, no LD surface treatment; IVO: 5.0% HF (IPS Ceramic Etching Gel, Ivoclar Vivadent); VIT: 5.0% HF (Vita Ceramics Etch, VITA Zahnfabrik); FGM: 5.0% HF (Condac Porcelana, FGM); ULT: 9.0% HF (Porcelain Etch, Ultradent); PRM: 9.6% HF (Premier Porcelain Etch Gel, Premier); BIS: 9.5% HF (Porcelain Etchant, Bisco Inc); DEN: 10.0% HF (Condicionador de Porcelanas, Dentsply Brazil); and MEP: self-etching ceramic primer (Monobond Etch & Prime, Ivoclar Vivadent). For all HF groups and control, an MDP-containing silane solution (MB+, Monobond Plus, Ivoclar Vivadent) was applied on rinsing the HF gel and air drying. Three transparent matrices for each specimen were filled with light-cured resin cement (Variolink Veneer, Ivoclar Vivadent). After storage in water for 48 hours at 37°C, specimens were tested in shear mode to measure μSBS. Mode of failure was analyzed at 50×. Statistical analysis included one-way analysis of variance and the Duncan post hoc test (α=0.05). Thirty-six additional LD specimens were assigned to the same experimental groups (n=4) and observed under a field-emission scanning electron microscope (FESEM) at magnifications ranging from 10,000× to 100,000×. Results: IVO resulted in statistically higher mean μSBS than all the other groups. MEP resulted in statistically lower μSBS than all HF groups. The failure mode for MEP was predominantly adhesive. The most frequent failure mode for the HF groups was mixed. CON resulted in 100% pretesting failures. For FESEM, no retentive pattern was observed for CON specimens. MEP resulted in the least pronounced etching pattern, few areas around crystals exhibited a slight increase in retention pattern compared to the control group. All HF gels created microporosities on the LD surface with distinct etching patterns. VIT and DEN resulted in an LD ultramorphology that suggested overetching. Conclusions: HF etching followed by a silane solution resulted in higher bond strengths than a self-etching ceramic primer. Some HF gels may cause overetching of the LD intaglio surface.

Resorbable Collagen Barrier Impeding the Extrusion of Obturating Material in Primary Molars Undergoing Resorption – A Randomized Clinical Trial

2021 ◽  
Vol 45 (5) ◽  
pp. 312-316
Author(s):  
Mishra Neha Sanjeev ◽  
Harsimran Kaur ◽  
Sandeep Singh Mayall ◽  
Rishika ◽  
Ramakrishna Yeluri
Keyword(s):  
Test Group ◽  
Primary Molars ◽  
Control Group ◽  
Chi Square ◽  
Significance Level ◽  
Significant Difference ◽  
Chi Square Test ◽  
Group A ◽  
Group B ◽  
And Control

Objective: To evaluate the effectiveness of placing a resorbable collagen barrier in impeding the extrusion of obturation material in primary molars undergoing resorption. Study design: All the 94 canals in 47 mandibular molars were allocated to 2 groups- Group ‘A’- 47 canals with collagen barrier (Test group) and Group ‘B’- 47 canals without collagen barrier (Control group) based on randomization protocol. Pulpectomy was performed and obturation of both test and control canals were radiographically assessed. Pearson’s chi – square test was applied to analyze the results. The significance level was predetermined at p &lt; 0.05. Results: Among the test group, 93.6% of the canals showed no extrusion while, 6.4% showed visible extrusion of the material outside the apex. In the control group, 83% showed no extrusion whereas 17% of the canals showed visible extrusion outside the apex. But no significant difference was noted (p&gt;0.05). Conclusion: The placement of resorbable collagen barrier in the apical third of the canal prevented the extrusion of obturating material beyond the apex in resorbing primary molars.

Evaluation of the effect of cetrimide with edta on Microhardness and surface changes in root dentin – An invitro study

2019 ◽  
Vol 11 (1) ◽  
pp. 3-11
Author(s):  
Dr. Swarooparanil Patil ◽  
Dr. B.S. Keshava Prasad
Keyword(s):  
Surface Erosion ◽  
Distilled Water ◽  
Test Results ◽  
Chi Square ◽  
Chi Square Test ◽  
Root Dentin ◽  
Group 3 ◽  
Post Hoc ◽  
Hardness Values ◽  
Surface Changes

The aim of the study was to evaluate the effect of different concentrations of cetrimide with or without EDTA solution on the microhardness and surface changes in root dentin. Single rooted human mandibular premolar teeth were decoronated and sectioned longitudinally. The root segments were horizontally embedded in autopolymerizing resin. These specimens were randomly divided into 6 experimental groups according to the irrigating solution used. The irrigating solutions used were 5% EDTA, 5%EDTA + 0.25% Cetrimide, 5%EDTA + 0.50% Cetrimide, 0.25% Cetrimide, 0.50% Cetrimide and distilled water. Each group was further divided into two subgroups. First subgroup specimens were employed for microhardness testing using vicker’s indenter. Second subgroup specimens were used to evaluate the surface changes of root dentin under stereomicroscope. Comparison of the mean microhardness of test groups was done using ANOVA followed by post hoc Tukey’s test. Pre- and post- treatment hardness values were compared using student paired t test. The data obtained from surface erosion scoring was subjected to statistical analysis using Chi square test. Results of this study showed significant reduction in the microhardness of dentin for all the groups except for the distilled water (p<0.001). The greatest reduction in dentin microhardness was observed with Group-3 (5% EDTA + 0.50% CTR). Specimens in 5% EDTA group showed greater erosion than other groups. Within the limitations of this study it was concluded that all the tested irrigating solutions reduced the microhardness of root dentin except distilled water. Maximum reduction in microhardness was observed with addition of 0.50% cetrimide to EDTA. EDTA increased the surface roughness of root dentin irrespective of cetrimide association. Use of cetrimide at concentrations higher than 0.25% would be detrimental to the microhardness of dentin.

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