scholarly journals In vitro Comparison of Compressive Strength of Bulk-fill Composites and Nanohybrid Composite

2016 ◽  
Vol 7 (3) ◽  
pp. 119-122
Author(s):  
K Pradeep ◽  
MA Kuttappa ◽  
Adarsh Kudva ◽  
Roshni Butula
Keyword(s):  
Compressive Strength ◽  
Light Emitting Diode ◽  
Testing Machine ◽  
In Vitro Study ◽  
Maximum Load ◽  
Test Analysis ◽  
Nanohybrid Composite ◽  
Group 2 ◽  
In Vitro Comparison

ABSTRACT Objectives The objective of this study is to measure and compare the compressive strength of two bulk-fill posterior composites (Smart dentin replacement or SDR and Filtek bulk fill) with universal nanohybrid composite (Filtek Z 250XT). Materials and methods In this in vitro study, three different types of posterior composites are used as follows: Group 1 – SDR (Dentsply, Konstanz, Germany); group 2 – Filtek bulk-fill (3M ESPE, St. Paul, MN, USA); group 3 – Filtek Z-250XT (3M ESPE, St. Paul, MN, USA). Ten cylindrical samples of 6 mm height and 4 mm diameter in each group were made using a split brass mold. The composites filled in the brass mold were photopolymerized using light-emitting diode (LED) light-curing unit and the cured samples were stored in water at 37°C for 48 hours before testing. The compressive strength of the stored samples was tested using universal testing machine (Instron 3366, UK) at a cross-head speed of 0.5 mm/minute. The compressive strength was calculated by dividing the maximum load with area of the samples. Results Results are statistically analyzed using one-way analysis of variance (ANOVA) with Tukey's post hoc test. Analysis showed that SDR and Filtek bulk-fill have greater compressive strength than Filtek Z-250 (p < 0.05). However, there is no statistical difference between compressive strength of SDR and Filtek bulk-fill composites (p > 0.05). How to cite this article Pradeep K, Ginjupalli K, Kuttappa MA, Kudva A, Butula R. In vitro Comparison of Compressive Strength of Bulk-fill Composites and Nanohybrid Composite. World J Dent 2016;7(3):119-122.

scholarly journals Effect of Thermocycling on the Compressive Strength of Selected Luting Cements

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
Al-Khadim Aws H. ◽  
Abdullah H. ◽  
Al-Ani Sarah T.
Keyword(s):  
Compressive Strength ◽  
Testing Machine ◽  
Glass Ionomer Cement ◽  
In Vitro Study ◽  
Chemical Compositions ◽  
Luting Cements ◽  
Group 2 ◽  
Adhesive Cement ◽  
Group 1

Introduction: The purpose of this in vitro study was to evaluate the effect of thermocycling on the compressive strength of selected luting cements. Material and methods: 5 types of luting cements were tested. A total of thirty cylindrical specimens measuring 6mm in height and 4mm in diameter were prepared for each type of cement which were then divided into two groups ie Group 1: Exposure, and Group 2: Control. Both groups were stored in distilled water at 37°C for 24 hours. Group 1 was subjected to 500 cycles in a thermocycling baths of 5ºC and 55ºC with 20 seconds in each bath. Group 2 was not exposed to thermocycling procedure. The compressive strength for each cement type was determined by using a universal testing machine. Results: Resin adhesive cement had the highest compressive strength; followed by conventional glass ionomer cement (GIC) whilst resin modified GIC was the least. Thermocycling had no significant effect on the compressive strength of RelyXTM ARC and Fuji I (p>0.05), but a significant effect on Fuji I CAPSULE, Fuji CEM, Fuji Plus CAPSLUE (p<0.05) was observed. Conclusion: The effect of thermocycling on the compressive strength of luting cements differed considerably with respect to their chemical compositions.

scholarly journals A COMPARATIVE EVALUATION OF MICROLEAKAGE, COMPRESSIVE STRENGTH, FLEXURAL STRENGTH AND FLUORIDE RELEASE OF ZIRCONOMER AND KETAC SILVER: AN IN VITRO STUDY.

2020 ◽  
Vol 9 (4) ◽  
Author(s):  
CHARANTEJA VEMAGIRI ◽  
Uloopi KS ◽  
Vinay Chandrappa ◽  
Anusha Ch
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Testing Machine ◽  
In Vitro Study ◽  
Biological Properties ◽  
T Test ◽  
Fluoride Release ◽  
Restorative Material ◽  
Glass Ionomer

Background: A successful restorative material forms a better adhesion, resist the microleakage and releases fluoride. However, existing glass ionomer cements cannot be used as a posterior restorative material in stress bearing areas. A new ionomer called Zirconomer, zirconia reinforced glass ionomer claims to exhibit high physical and biological properties. Aim: To assess and compare the microleakage, compressive strength, flexural strength and fluoride release from zirconomer with ketac silver. Materials & Methods: On twenty caries free premolar teeth (10 per each group), a class v cavity was restored with zirconomer and ketac silver. The microleakage was assessed using dye penetration test and stereomicroscope. The compressive and flexural strengths of these materials were measured using Instron Universal testing machine. The amount of fluoride released from the modified ionomers at pH 5 and pH 7 was estimated using Orion fluoride specific electrode. The obtained data was then subjected to statistical analysis. Results: Data was analysed using paired t-test for intergroup comparisons and unpaired t-test for intragroup comparisons. The overall microleakage (0.5±0.48) of zirconomer was significantly less (p=0.000) compared to ketac silver (1.9±0.83). Zirconomer demonstrated a significant higher compressive strength (330.25±60.14), flexural strength (33.058±2.36) than ketac silver (p= 0.000). Zirconomer demonstrated high fluoride release from day 1 to day 7 at both pH 5 and pH 7. Conclusion: Zirconomer demonstrated better physical and biological properties compared with ketac silver.

Evaluation of physical and adhesive properties of enamel after a therapeutic dose of radiation and bonding of orthodontic metal brackets: an in vitro study

2020 ◽  
pp. 1-5
Author(s):  
A. Anushree ◽  
Ashutosh Shetty ◽  
Crystal Runa Soans ◽  
M. N. Kuttappa ◽  
Akhil Shetty ◽  
...  
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Tooth Surface ◽  
Control Group ◽  
Adhesive Properties ◽  
Adhesive Resin ◽  
Adhesive Remnant Index ◽  
Group 3 ◽  
Group 2

Abstract Aim: The study aimed to evaluate the shear bond strength (SBS) of metal brackets and adhesive properties of bonded irradiated and non-irradiated teeth. Methods: Sixty-six extracted premolar samples were randomly divided into three groups—(a) Control group consisting of 22 non-irradiated, non-aged teeth (Group 1), (b) 22 non-irradiated, aged samples (Group 2) and (c) 22 irradiated, aged samples (Group 3). Irradiation was done using gamma irradiation with a fractionated dose of 60 Gy for 5 consecutive days per week over 6 weeks. Metal brackets were bonded on all samples with light cure adhesive and subjected to SBS test using universal testing machine. The samples were assessed under the scanning electron microscope to check for the adhesive remnant index (ARI) and tag depth. Results: There was a statistically significant decrease in the mean SBS of the irradiated samples compared to the non-irradiated teeth. The non-irradiated, aged samples showed a majority of ARI scoring 1 and 2. Whereas, the irradiated samples showed ARI scoring 2 and 3. Approximately, 77·3% of the non-irradiated samples showed no adhesive present on the tooth surface, and 27·2% of the irradiated samples had more than 50% adhesive present on the enamel surface. Conclusion: There is a statistically significant decrease in SBS of irradiated enamel compared to that of non-irradiated teeth. However, the SBS observed in the three groups was well above the ideal SBS for orthodontic bonding, that is, 5·6–6·8 MPa. The adhesive remnant was found on all samples of the irradiated group. Deeper adhesive resin tags were found in the irradiated group in the resin–enamel interface.

scholarly journals Orthodontic brackets’ shear bond strengths after applying remineralizing agents

2021 ◽  
Vol 11 (2) ◽  
pp. 67-74
Author(s):  
Yusuf Özant ◽  
Yazgı Ay Ünüvar
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Orthodontic Brackets ◽  
Fluoride Varnish ◽  
Demineralized Enamel ◽  
Bond Strengths ◽  
Group 5 ◽  
Group 2 ◽  
Casein Phosphopeptide

Aim: The aim of this in vitro study was to measure the effects of white spot lesions treatment agents on the shear bond strengths (SBSs) and adhesive residual indexes (ARIs) of orthodontic brackets. Methodology: This study used 100 human premolar teeth randomly divided into five groups. Group 1 comprised those with intact enamel, Group 2 comprised those with demineralized enamel and Groups 3–5 comprised those demineralized enamel that was treated with casein phosphopeptide amorphous calcium phosphate fluoride (CPP-ACPF), fluoride varnish and a resin infiltrant, respectively. Brackets were bonded to the teeth using the conventional method, then the samples were thermocycled and tested for SBS using a universal testing machine. The adhesive remnant indexes (ARI) of the brackets were also evaluated. One-way ANOVA and post-hoc Tukey tests were used to compare the groups’ SBSs and the Kruskal–Wallis test was used to evaluate the groups’ ARI scores. Results were considered statistically significant if p was less than 0.05. Results: Statistically significant differences were found between the groups (F was 6.895 and p was less than 0.001). The SBSs of the brackets in Group 4 were significantly lower than those of the other groups (the mean was 13.44 ± 6.37 MPa). Group 5 had the highest mean SBS value (22.11 ± 6.56 MPa). Additionally, the ARI scores of the four groups were significantly different (p was less than 0.001). Conclusion: Resin infiltration and CPP-ACPF applications can improve bonds to demineralized enamel, while fluoride varnish applications are not recommended for such enamel.   How to cite this article: Özant Y, Ay Ünüvar Y. Orthodontic brackets’ shear bond strengths after applying remineralizing agents. Int Dent Res 2021;11(2):67-74. https://doi.org/10.5577/intdentres.2021.vol11.no2.3   Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Does Addition of Propolis to Glass Ionomer Cement Alter its Physicomechanical Properties? An in Vitro Study

2016 ◽  
Vol 40 (5) ◽  
pp. 400-403 ◽  
Author(s):  
P Subramaniam ◽  
KL Girish Babu ◽  
G Neeraja ◽  
S Pillai
Keyword(s):  
Compressive Strength ◽  
Testing Machine ◽  
Glass Ionomer Cement ◽  
In Vitro Study ◽  
Physicomechanical Properties ◽  
Control Group ◽  
Glass Ionomer ◽  
Experimental Group ◽  
Ionomer Cement

Propolis is a natural resinous substance produced by honey bees. The antimicrobial effects of glass ionomer cement have been shown to improve with the addition of propolis; however its effect on the physicomechanical properties of the cement is not known. Aim: The purpose of this study was to evaluate the compressive strength and solubility of conventional restorative glass ionomer cement following the addition of propolis. Study design: Twenty half cylindrical samples were prepared with conventional restorative glass ionomer cement formed the control group. Another twenty samples were prepared with propolis added to conventional restorative glass ionomer cement formed the experimental group. The compressive strength was assessed using universal testing machine. To assess solubility, the samples were immersed in deionised water at room temperature, for 7 days. The solubility was measured as a difference in the weight of the sample; prior to immersion and following immersion at the end of each day. Results: The control group had a significantly higher mean compressive strength of 146.26 Mpa as compared to the experimental group (135.06 Mpa). The solubility between the groups was significant. Conclusion: In comparison to the control group, incorporation of propolis to conventional restorative glass ionomer cement decreased the compressive strength significantly. The solubility of the cement in the experimental group increased significantly over 7day period as compared to the control group.

Comparative Biomechanical Characteristics of Modified Side-to-Side Repair and Modified Pulvertaft Weaving Repair – In vitro Study

2019 ◽  
Vol 24 (01) ◽  
pp. 76-82
Author(s):  
Sudhir Kannan ◽  
Arijit I. Ghosh ◽  
Joseph J. Dias ◽  
Harvinder Pal Singh
Keyword(s):  
Tensile Stress ◽  
Testing Machine ◽  
In Vitro Study ◽  
Early Mobilization ◽  
Maximum Load ◽  
Mode Of Failure ◽  
Mechanical Basis ◽  
Anchor Points ◽  
Biomechanical Strength

Background: Strong surgical repair is the mechanical basis of early mobilization and prerequisite for biological healing following tendon grafting. Side to side and pulvertaft repairs were developed to meets these demands. However, these techniques have later been modified to improve the strength of repair but their characteristics have not been compared. Methods: We compared biomechanical strength of the modified side-to-side (SS) repair with the modified Pulvertaft (PT) repair technique in turkey tendons keeping overlap length, anchor points, type of suture, suture throw and amount of suture similar. Two investigators performed 34 repairs during one summer month to test the tensile strength of the repair using mechanical strength testing machine. Variables measured were maximum load, load to first failure, modulus, load at break, mode of failure, site of failure, tensile strain, tensile stress. The statistical comparison was carried by Levene’s test and T test for means. Results: The mean maximum load for modified SS repair was 50.3 (SD 13.7) N and modified PT repair was 46.9 (SD 16.4) N. The tensile stress at maximum load for SS and modified PT repair was 4.7 (SD 4) MPa and 4.2 (SD 3) MPa respectively. The suture cut through was the commonest mode of failure. Conclusions: We found no statistical difference between 2 repairs in load at which they started failing (p = 0.16), and maximum load repairs could withstand (p = 0.35). Our study uniquely compares two techniques under standard conditions, and contrary to existing evidence found no difference. However, in our opinion the number of anchor points may have a greater impact than number of weaves on the strength.

scholarly journals Experimental Investigation of the Influence of Chlorhexidine Gel on the Implant-Abutment-Connection

2020 ◽  
Author(s):  
Lisa Mandlbauer ◽  
Vasilios Alevizakos ◽  
Ahmed Othman ◽  
Marcus Stoetzer ◽  
Constantin von See
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Control Group ◽  
Removal Torque ◽  
Significance Level ◽  
Saliva Substitute ◽  
Group 3 ◽  
Group 2 ◽  
Chlorhexidine Gel

Abstract Background The aim of this study was to determine the effect of chlorhexidine gel on removal torque of abutment prosthesis screws in vitro. Methods 60 implants (BEGO Semados ® S/RI 4.1, BEGO Implant Systems GmbH & Co. KG, Bremen, Germany) were embedded in acrylic resin for study set-up. The abutments (S/RI 4.1 SUB-TEC WI, BEGO Implant Systems GmbH & Co. KG, Bremen, Germany) were fixed with prothesis screws with 25 Ncm on the implants and were loaded for 10.000 cycles with 250N in a static material testing machine. The implemented study consisted of three groups (n=20). Group 1 (control group) were loaded under dry conditions. Group 2 was filled with a saliva substitute only (Sialin-Sigma solution, Sigmapharm Arzneimittel GmbH, Vienna, Austria), group 3 was filled with a saliva substitute and additional with chlorhexidine gel (Chlorhexamed 1% GEL, GlaxoSmithKline Consumer Healthcare GmbH & Co. KG, München, Germany). Statistical analysis was performed using ANOVA (significance level p<0.05). Results The control group showed the smallest range of removal torque (19.85 Ncm ± 1.42 Ncm) while group 2 showed 20.32 Ncm ± 2.61 Ncm and in group 3 was 19.74 Ncm ± 2.96 Ncm. No significant differences between the three groups were evaluated. Conclusions Within the limits of this in-vitro study, it can be concluded that the application of chlorhexidine gel did not show any significant effect on the removal torque on abutment screws after loading.

scholarly journals Mathematical validation of measurement of root fracture resistance: an in vitro study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Rafat Bagheri ◽  
Abbas Abbaszadegan ◽  
Mohammad R. Nabavizadeh ◽  
Maryam Ferooz ◽  
Peter Parashos
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Maximum Load ◽  
Control Groups ◽  
Root Fracture ◽  
Root Canals ◽  
Gutta Percha ◽  
Root Fracture Resistance

Abstract Background The aim of this study was to develop a mathematically valid method of assessing fracture resistance of roots. The model developed used mesial roots of lower molars instrumented using stainless steel hand files (SS) and two rotary nickel-titanium (NiTi) systems. Methods Eighty human lower molars were selected and randomly divided into four groups (n = 20). After instrumentation, the root canals were obturated using thermoplasticized gutta percha. The roots were covered with a simulated periodontal ligament and mounted vertically in autopolymerizing acrylic in PVC tubes. Using a universal testing machine, the force to fracture (N) was applied and the maximum load (FL) was recorded. Remaining dentine volume was calculated and the fracture resistance (FR) was recorded. The data were analyzed using SPSS version 22 with P < .05. Results There were no significant differences among the instrumentation methods for FL but in FR the roots instrumented using rotary NiTi showed significantly lower values than control groups and SS files (P < 0.001). Conclusions Considering the effect of root length, volume of the root, and volume of the instrumented canal as well as the maximum failure load may be a more objective method of reporting fracture resistance of roots.

scholarly journals Fracture Resistance of CAD/CAM Versus Traditional Interim Fixed Dental Prostheses

2018 ◽  
Vol 55 (3) ◽  
pp. 361-363
Author(s):  
Daniel Alexandru Pop ◽  
R. Malaescu ◽  
Liviu Marsavina ◽  
Tiberiu Hosszu ◽  
Raul Rotar ◽  
...  
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Maximum Load ◽  
Fracture Load ◽  
Digital Design ◽  
Computer Assisted ◽  
Dental Prostheses ◽  
Cad Cam ◽  
Fixed Dental Prostheses

The aim of this in vitro study is to compare the load-to-fracture performance of polymethyl methacrylates (PMMA) provisional restorations manufactured with a traditional laboratory technique in comparison to a computer-assisted design and computer-assisted manufacturing (CAD-CAM) technique. Five interim three-unit fixed dental prostheses were fabricated with the conventional indirect technique, on a standard typodont. The same model was scanned with an intraoral scanner and the digital design of identical fixed dental prostheses was made. Then other five interim three-unit fixed dental prostheses were milled from PMMA CAD/CAM blocks with an in office milling machine. All specimens were tested for flexural strength in a universal testing machine, and the maximum load to fracture was measured. For the conventional provisional restorations, the load to fracture was 121.16 � 24.6, in comparison to CAD/CAM interim restorations, for which the load to fracture was 728.88 � 228.7. Within the limitations of this study, one can conclude that CAD/CAM provisional restorations present a higher fracture load than the conventional manufactured interim restorations.

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