scholarly journals AN IN VITRO STUDY TO EVALUATE THE TEAR STRENGTH OF AUTOCLAVABLE PVS, SMART WETTING PVS AND CONDENSATION SILICONE AND COMPARE THEM UPON AUTOCLAVING AND DISINFECTION.

2020 ◽  
pp. 67-70
Author(s):  
Garima Gothwal ◽  
Hemant Kumar Sharma ◽  
Kusum Singh ◽  
Richa Sengar
Keyword(s):  
Statistical Analysis ◽  
Testing Machine ◽  
In Vitro Study ◽  
Tear Strength ◽  
Universal Testing ◽  
Impression Materials ◽  
Different Types ◽  
Post Hoc ◽  
One Way Anova

Aim: The tear strength of three different types of elastomeric impression materials was measured after disinfection and sterilization. Material and Method: Dumb-bell shaped Tear strength specimens were prepared according to ISO 34-1 standardization. Ninety samples were prepared followed by disinfection and sterilization and tested with trouser piece method on Instron universal testing machine at a speed of 10 mm/min. One-way ANOVA, followed by Tukey post hoc test was used for statistical analysis. Results: No signicant difference was found when AFFINIS, SPEEDEX and AQUASIL were compared individually. When materials were compared with each other signicant difference was present, highest AQUASIL while SPEEDEX and AFFINIS almost alike. Conclusion: It was concluded that tear strength of AQUASIL was the highest. Disinfection and autoclaving had no signicant inuence on the three materials and showed adequate tear strength.

scholarly journals Debonding characteristics of orthodontic brackets subjected to intraoral stresses under different adhesive regimes: An in-vitro study

2020 ◽  
Vol 18 ◽  
pp. 228080001989964
Author(s):  
Khalid M Abdelaziz ◽  
Ibrahim Alshahrani ◽  
Muhammad Abdullah Kamran ◽  
Abdullah Alnazeh
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Mechanical Stresses ◽  
Orthodontic Brackets ◽  
Short Term ◽  
Universal Testing ◽  
Etch And Rinse ◽  
Different Types ◽  
Self Etch

Aim: To evaluate the effect of simulated intraoral hydraulic, thermal, and mechanical stresses on the debonding characteristics of orthodontic brackets under different adhesive regimes. Materials and methods: Groups of pre-coated (G1) and non-coated (G2) orthodontic metal brackets were bonded onto the buccal surfaces of 96 premolars using etch-and-rinse (SG1, n = 24) and self-etch (SG2, n = 24) primers. Twelve specimens (C1) from each subgroup were subjected to early debonding resistance tests, while the other twelve (C2) were used to test delayed debonding resistance after exposure to conditions simulating intraoral hydraulic, thermal, and mechanical stresses. The debonding resistance of the brackets was evaluated using a universal testing machine and the debonding patterns were micro-visualized to determine the adhesive remnant indexes of subgroups of specimens. Results: Within each group, the etch-and-rinse primer (SG1) resulted in higher debonding resistance than self-etch primers (SG2) ( p < 0.05), while there was no difference between non-stressed and stressed specimens ( p > 0.05). Within each category of test specimens, there was no difference between pre-coated (G1) and non-coated (G2) brackets ( p > 0.05). The tested specimens in all categories showed comparable adhesive remnant indexes. However, higher percentages of favorable scores (0 and 1) were obtained for all stressed specimens. Conclusions: Short-term cumulative intraoral stresses have no adverse effect on the debonding values of either pre-coated or non-coated brackets when either etch-and-rinse or self-etch primer is used for bonding. Exposure of the bonded brackets to different types of stress reflects favorable debonding patterns.

scholarly journals The Effect of Translucency and Surface Treatment on the Flexural Strength of Aged Monolithic Zirconia

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Rashin Giti ◽  
Benika Abbasi
Keyword(s):  
Flexural Strength ◽  
Surface Treatment ◽  
Testing Machine ◽  
In Vitro Study ◽  
High Strength ◽  
Airborne Particle ◽  
Different Types ◽  
Monolithic Zirconia ◽  
Post Hoc

Aims. This in vitro study aimed to evaluate the effect of the degrees of translucency in different types of monolithic zirconia as well as the aging and surface treatment with airborne particle abrasion on the flexural strength of monolithic zirconia. Materials and Methods. Sixty bar-shaped specimens were fabricated from three different types of presintered monolithic zirconia (n = 20 per group) including low translucent (LT) (DD Bio ZW iso, high strength zirconia, Dental Direkt, Germany), high translucent (HT) (DD Bio ZX2 98, high translucent zirconia, Dental Direkt, Germany), and multilayered system (ML) (DD cubeX2®ML, multilayer, cubic zirconia system, Dental Direkt, Germany). Each monolithic zirconia group was equally subdivided according to be either air-abraded with 110 µm aluminium oxide particles or left untreated (control). After thermocycling, the flexural strength was measured by using a universal testing machine. Two-way ANOVA followed by Tukey’s post hoc and independent samples t-test were used for the statistical analyses (P < 0.05). Results. Surface treatment and types of zirconia were found to have a significant interaction (P = 0.010). Having controlled the effect of surface treatment, the flexural strength of HT and LT zirconia was found to be significantly higher than the ML zirconia system (P ≤ 0.001). Airborne particle abrasion could significantly decrease the flexural strength of monolithic zirconia only in ML zirconia (P = 0.002). Conclusions. Multilayered zirconia system had the lowest flexural strength among all groups. Moreover, the flexural strength of this system was attenuated by surface treatment with airborne particles abrasion.

scholarly journals Shear Bond Strength of Different Adhesive Materials used for Bonding Orthodontic Brackets : A Comparative in vitro Study

2015 ◽  
Vol 5 (1) ◽  
pp. 22-26
Author(s):  
Muzin Shahi Shaik ◽  
Snigdha Pattanaik ◽  
Sudhakar Pathuri ◽  
Arunachalam Sivakumar
Keyword(s):  
Bond Strength ◽  
Treatment Duration ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Test Group ◽  
In Vitro Study ◽  
Universal Testing ◽  
Materials Used ◽  
Adhesive Materials

Introduction: Bond strength is an important property and determines the amount of force delivered and treatment duration in orthodontics. Many light-cured bonding materials are being used; but it is required to determine the most efficient one withdesired bond strength. Objective: To determine and compare the shear bond strength of three visible light-cured composites (Transbond XT, Heliositand Enlight) and two self-cured composites (Rely-a-bond and Concise). Materials & Method: 100 extracted premolars were collected and randomly divided into 5 test groups of different adhesives. Brackets were bonded to the teeth in each test group with the respective adhesive according to the manufacturer’s instructions. Each specimen was debonded using Universal Testing Machine and the shear bond strength for each specimen was calculated. All the groups were compared by ANOVA one-way test. Results: There were statistically significant differences among the five groups (P<0.05). The shear bond strength of Enlight (13.92 ± 3.92) is similar to Transbond XT (14.30 ± 4.35). Conclusion: Light cure composites showed higher bond strength than self cure composites.

scholarly journals Depth-Related Curing Potential of Ormocer- and Dimethacrylate-Based Bulk-Fill Composites

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6753
Author(s):  
Ramona S. Oltramare ◽  
Reto Odermatt ◽  
Phoebe Burrer ◽  
Thomas Attin ◽  
Tobias T. Tauböck
Keyword(s):  
Double Bond ◽  
Repeated Measures ◽  
In Vitro Study ◽  
High Viscosity ◽  
Degree Of Conversion ◽  
Double Bond Conversion ◽  
Nanohybrid Composite ◽  
Post Hoc ◽  
One Way Anova

The aim of this in vitro study was to investigate the degree of C=C double bond conversion of high-viscosity dimethacrylate- or ormocer-based bulk-fill composites as a function of measurement depth. Four bulk-fill composites (Tetric EvoCeram Bulk Fill, x-tra fil, SonicFill, and Bulk Ormocer) and the conventional nanohybrid composite Tetric EvoCeram were applied in standardized Class II cavities (n = 6 per group) and photoactivated for 20 s at 1350 mW/cm2. The degree of conversion of the composites was assessed using Fourier-transform infrared spectroscopy at seven measurement depths (0.15, 1, 2, 3, 4, 5, 6 mm). Data were analyzed using repeated measures ANOVA and one-way ANOVA with Bonferroni post-hoc tests (α = 0.05). The investigated bulk-fill composites showed at least 80% of their maximum degree of conversion (80% DCmax) up to a measuring depth of at least 4 mm. Tetric EvoCeram Bulk Fill and Bulk Ormocer achieved more than 80% DCmax up to a measuring depth of 5 mm, x-tra fil up to 6 mm. The conventional nanohybrid composite Tetric EvoCeram achieved more than 80% DCmax up to 3 mm. In contrast to the conventional composite, the investigated ormocer- and dimethacrylate-based bulk-fill composites can be photo-polymerized in thick layers of up to at least 4 mm with regard to their degree of C=C double bond conversion.

scholarly journals Effect of clasp type and pullout location on clasp retention in different environment: In vitro study

2017 ◽  
Vol 11 (02) ◽  
pp. 216-220 ◽  
Author(s):  
Bilal Mourshed ◽  
Fuad Abdo Al-Sabri ◽  
Nashwan Ahmed Qaed ◽  
Nader Alaizari ◽  
Hashem Motahir Al-Shamiri ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
In Vitro Study ◽  
Retentive Force ◽  
Crosshead Speed ◽  
Tukey Test ◽  
Retention Force ◽  
Test Models ◽  
Molar Teeth ◽  
One Way Anova

ABSTRACT Objective: The purpose of this study was to investigate the importance of pullout location and clasp types in two different environments to dislodge the clasp. Materials and Methods: Mandibular test models with natural premolars and molar teeth were used to test four types of clasp (each 12) (Akers, Rest plate Akers, Half and Half, and Ring clasp) with three different pullout location for each type (ring on the rest, loop on the saddle, and wax arising from both rests) in dry and natural fresh saliva environment. Each clasp was pulled out 10 times with a crosshead speed of 10 mm/min, and the force required to withdraw each was measured. Statistical Analysis Used: A one-way ANOVA and Tukey test were used. Results: The ring on the saddle pullout location has the highest retention force while ring on the rest was the lowest. In addition, ring clasp has the highest retention force. Conclusion: Clasp type and pullout location had a significant effect on the retentive force.

The Effect of Thermoforming on Tear Strength of Ethylene Vinyl Acetate Mouthguard Material in Various Thicknesses

2017 ◽  
Vol 751 ◽  
pp. 657-662
Author(s):  
Phakphum Srinuan ◽  
Jeerapatr O. Baiyokvichit ◽  
Rasana Boonpeng ◽  
Tanapol Wongwisatekit ◽  
Pacharaporn Pattanasukwasan ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Testing Machine ◽  
Ethylene Vinyl Acetate ◽  
Strength Test ◽  
Tear Strength ◽  
Universal Testing ◽  
Significant Difference ◽  
The Mean ◽  
Thermoforming Process ◽  
One Way Anova

The effect of thermoforming on the tear strength of ethylene vinyl acetate (EVA) mouthguard material (Bioplast®) has not been widely investigated. The present study compared the tear strengths of non-processed and processed EVA specimens in various thicknesses. Two groups of EVA sheet (non-processed and processed) in three different thicknesses of 3, 4 and 5 mm were used in specimen fabrication. The processed EVA sheets were achieved by forming the EVA sheet on the cylindrical stone model with the pressure-molding device (Biostar®). Twelve of tear strength specimens of non-processed and processed group in each thickness were prepared following the modified ASTM D 624-00 guideline. The tear strength test was conducted using universal testing machine (Lloyd® 1K series) with the speed of 500 mm/min. The mean thickness and tear strength of the non-processed and processed specimens in each thickness were compared using independent T-test. The differences in the mean tear strength for each thickness of non-processed and process specimens were determined using one-way ANOVA. The mean tear strength and mean thickness of processed EVA specimens was significantly lower than the non-processed EVA specimens for every thickness (P ≤ 0.05). There was no significant difference in the mean tear strength of EVA specimens among each thickness in both non-processed and processed groups. It can be concluded that the thermoforming process has the significant effect on the tear strength of the EVA mouthguard material formed by pressure molding device in every thicknesses. The tear strength of processed specimens were significant lower than the non-processed. Thus, it is more relevant for testing properties of the processed mouthguard material that the mouthguard material before processing.

scholarly journals The influence of different screw tightening forces on the vertical misfit of implant-supported frameworks

2005 ◽  
Vol 13 (2) ◽  
pp. 120-125 ◽  
Author(s):  
Diego Klee de Vasconcellos ◽  
Marco Antonio Bottino ◽  
Renato Sussumu Nishioka ◽  
Luiz Felipe Valandro ◽  
Elza Maria Valadares da Costa
Keyword(s):  
Repeated Measures ◽  
In Vitro Study ◽  
Pairwise Comparisons ◽  
Tukey Test ◽  
Nickel Chromium ◽  
Marginal Discrepancy ◽  
The Mean ◽  
Post Hoc ◽  
One Way Anova

OBJECTIVES: The present in vitro study was designed to compare the differences in the vertical misfit of implant-supported frameworks using three different forces for tightening the bridge locking screws: fastening by hand until first resistance, and using torque drivers with 10 and 20Ncm. METHODS: The investigation was conducted based on the results given by 9 six-unit nickel-chromium (2 abutments/ 4 pontics) screw-retained implant-supported frameworks. The structures were exposed to simulated porcelain firings. The marginal misfit measurements were made using a traveling measuring microscope at selected screw tightening forces: fastening by hand until first resistance, and using torque drivers with 10 and 20Ncm. The results were submitted to one-way ANOVA with repeated measures on one factor, and post hoc pairwise comparisons using Tukey test (5%). RESULTS: The mean marginal misfit of the frameworks, fastening the screws by hand until first resistance, was 41.56µm (SD±12.45µm). The use of torque driver devices caused a significant reduction in marginal opening (p<0.05). With the lowest torque available (10Ncm), the mean marginal discrepancy at the abutment-framework interface was reduced an average of 52% to a mean marginal opening of 19.71µm (SD±2.97µm). After the use of the 20Ncm torque driver, the mean marginal discrepancy of the frameworks was reduced an average of 69% to a mean marginal opening of 12.82µm (SD±4.0µm). Comparing the use of torque drivers with 10 and 20 Ncm torque, the means are not significantly different from one another. CONCLUSION: The seating force has an important effect on the vertical misfit measurements, once it may considerably narrow the vertical misfit gaps at the abutment-framework interface, thus leading to a misjudgment of the real marginal situation.

scholarly journals Effect of Chemical Disinfectant on the Transverse Strength of Heat-polymerized Acrylic Resins Subjected to Mechanical and Chemical Polishing: An in vitro Study

2012 ◽  
Vol 13 (3) ◽  
pp. 389-393
Author(s):  
Deepthi Kalahasti ◽  
Smitha Sharan ◽  
Harish Konde
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Chemical Polishing ◽  
Denture Base ◽  
Transverse Strength ◽  
Acrylic Resins ◽  
Universal Testing ◽  
Chemical Solutions ◽  
Chemical Disinfectant

ABSTRACT Aims To evaluate the effect of chemical disinfectant on the transverse strength of heat-polymerized acrylic resins subjected to mechanical and chemical polishing. Materials and methods A total of 256 rectangular specimens (65 × 10 × 3 mm) 128 per resin (Lucitone-199 and Acralyn-H) were fabricated. One side of each specimen was not polished and the other was either mechanically (n = 96) or chemically (n = 96) polished and immersed for 10, 30 and 60 minutes in 2% alkaline glutaraldehyde. Mechanically polished (n = 32) and chemically polished (n = 32) control specimens were immersed only in distilled water. The transverse strength (N/mm2) was tested for failure in a universal testing machine, at a crosshead speed of 5 mm/min. Data were statistically analyzed using 2-way ANOVA and Student t-test. Results chemical polishing resulted in significantly lower transverse strength values than mechanical polishing. Lucitone- 199 resin demonstrated the highest overall transverse strength for the materials tested. Heat-polymerized acrylic resins either mechanically or chemically polished, did not demonstrate significant changes in transverse strength during immersion in the disinfecting solution tested, regardless of time of immersion. Conclusion Lucitone-199 resin demonstrated the highest overall transverse strength for the materials tested and significantly stronger than Acralyn-H with either type of polishing following immersion in 2% alkaline glutaraldehyde. Clinical significance There is a concern that immersion in chemical solutions often used for cleansing and disinfection of prostheses may undermine the strength and structure of denture base resins. In this study it was observed that, the transverse strength of samples of Lucitone-199 was higher than that of the samples of Acralyn-H. The chances of fracture of the denture made of Lucitone-199 are less than that of dentures made of Acralyn-H. The chemically polished dentures may be more prone to fracture than mechanically polished dentures. How to cite this article Sharan S, Kavitha HR, Konde H, Kalahasti D. Effect of Chemical Disinfectant on the Transverse Strength of Heat-polymerized Acrylic Resins Subjected to Mechanical and Chemical Polishing: An in vitro Study. J Contemp Dent Pract 2012;13(3):389-393.

scholarly journals Effect of Incorporation of Disinfectants on Surface Hardness and Dimensional Accuracy of Die Stone: An in vitro Study

2017 ◽  
Vol 7 (3) ◽  
pp. 86-91
Author(s):  
Anubhuti Bakshi ◽  
Rajat Dang
Keyword(s):  
Sodium Hypochlorite ◽  
Testing Machine ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Control Group ◽  
Time Interval ◽  
Type Iv ◽  
Post Hoc

ABSTRACT Aim To evaluate surface hardness and dimensional accuracy of type IV dental stone after incorporation of disinfectants. Materials and methods A total of 100 specimens, 50 (40 mm⨯ 10 mm) disk shaped and 50 frustum cone shaped, were fab- ricated from type IV dental stone after incorporation of various disinfectants, namely glutaraldehyde (2%), iodophor (1.76%), chlorhexidine (2%), and sodium hypochlorite (1%), for evaluation of surface hardness and dimensional accuracy. Surface hardness was tested after 1- and 24-hour time interval using Rockwell hard- ness testing machine. Dimensional accuracy was measured using traveling microscope. Data obtained were compiled and analyzed statistically by using analysis of variance and post hoc test. Results Results showed significant decrease in surface hard- ness of samples incorporated with disinfectants at 1 hour as compared with control (distilled water). Surface hardness of all the samples increased with time and was almost equal to control group at 24-hour interval, with iodophor showing the maximum value in comparison with the other disinfectants used. When dimensional accuracy of all the groups was compared, iodophor and sodium hypochlorite were found to cause negative alterations. Conclusion Within the limitations of this in vitro study, it was concluded that incorporation of disinfectants in die stone during mixing did not affect the hardness value at 24-hour interval. Dimensional accuracy was altered by iodophor and sodium hypochlorite, but remained unaffected by chlorhexidine and glutaraldehyde. How to cite this article Bakshi A, Dang R. Effect of Incorpo- ration of Disinfectants on Surface Hardness and Dimensional Accuracy of Die Stone An in vitro Study. Int J Prosthodont Restor Dent 2017;7(3):86-91.

Comparative evaluation of shear bond strength of composite to dentin in presence of different dental liners: An in-vitro study

2021 ◽  
Author(s):  
Ladan Ranjbar Omrani ◽  
Saba Tohidkhah ◽  
Elham Ahmadi ◽  
Mahdi Abbasi ◽  
Reza Morvaridi Farimani
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Resin Composite ◽  
Testing Machine ◽  
Glass Ionomer Cement ◽  
In Vitro Study ◽  
Control Group ◽  
The One ◽  
Post Hoc

Abstract Background: The aim of the current study was to evaluate and compare the influence of Dycal, Lime-lite, Theracal LC, Biodentine, Resin-modified glass ionomer cement (RMGIC), and Activa Bioactive as the pulp capping material on the shear bond strength of resin composite to dentin.Methods: A total of 70 extracted caries-free molars were randomly assigned to seven groups. Six test groups were covered with various protective liners: Dycal (GD), Theracal LC (GT), lime-lite (GL), Activa Bioactive (GA), Biodentine (GB), RMGIC (GR). The control group (GC)received no liner pretreatment. Each sample was bonded to resin composite using the total-etch tetric N bond adhesive. The samples were then tested for shear bond strength using the universal testing machine at a cross-head speed of 1 mm/min until bond failure occurred. The data were analyzed using the one-way ANOVA test followed by the Tamhane post-hoc test for pairwise comparisons of the groupsResults: Independent of the type of the applied liner, all groups exhibited inferior SBS to dentine compared to the control group. GT and GR showed significantly higher shear bond strength than GB and GD, which showed the lowest shear bond strength. GL and GA also had significantly lower SBS results than GT. The mode of fracture was predominantly cohesive in GD, GB, and GT and adhesive in GA.Conclusion: This present study concludes that the bond strength of resin-composite to dentine can be affected differently using various types of liners.

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