scholarly journals Surface Hardness of Hybrid Ionomer with Different Curing Time (In Vitro Study)

2017 ◽  
Vol 1 ◽  
Author(s):  
Arfita Sipahutar ◽  
Astrid Yudhit ◽  
Rusfian Rusfian
Keyword(s):  
Standard Deviation ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Hardness Test ◽  
Curing Time ◽  
Mean Values ◽  
The Mean ◽  
One Way Anova ◽  
Group 1

<p class="AbstractContent"><strong>Objective:</strong> The aim of this study was to evaluate the surface hardness of hybrid ionomer with different curing times (20, 30, 40, and 50 seconds).</p><p class="AbstractContent"><strong>Methods</strong>: This was an experimental laboratory with posttest only group design. Twenty-four disk shape hybrid ionomer specimens with a diameter of 5 mm and 2 mm in thickness were prepared and polymerized with Quartz Tungsten Halogen (QTH) for 20, 30, 40, and 50 seconds as group 1, 2, 3, and 4 respectively. All samples were immersed in distilled water under 37°C temperature for 24 hours as initial treatment. Surface hardness test was done using Vickers Hardness Test with load 50 gf for 20 second. The Data was analyzed with one way ANOVA (<em>p </em>≤ 0.05).</p><p class="AbstractContent"><strong>Results</strong>: Using one way anova test (<em>p </em>≤ 0.05) shows the mean and standard deviation of the group 1 is 25,900 ± 2,5659VHN; group 2 is 29,800 ± 1,1983 VHN; group 3 is 31,283 ± 0,5037 VHN; group 4 is 36, 183 ± 2,3430 VHN and the obtained value <em>p </em>= 0.000 (<em>p </em>≤ 0.05).</p><p class="AbstractContent">The mean values and standard deviation were 25.900 ± 2.5659 VHN; 29.800 ± 1.1983 VHN; 31.283 ±0.5037 VHN; 6.183 ± 2.3430 VHN for group 1, 2, 3, and 4 respectively. Statistic analyzed showed a significant different among groups with <em>p</em> value =0.000 (<em>p</em> &lt; 0.05).</p><strong>Conclusion</strong> There are significant differences in surface hardness of hybrid ionomer with different curing time (20, 30,40, and 50 seconds). The longer curing time will increase the surface hardness of hybrid ionomer.

scholarly journals Toothbrush-Dentifrice Abrasion of Dental Sealants: An In Vitro Study

2021 ◽  
Author(s):  
Angkhana Sangpanya ◽  
Pornpoj Fuangtharnthip ◽  
Vanida Nimmanon ◽  
Praewpat Pachimsawat
Keyword(s):  
Abrasive Wear ◽  
In Vitro Study ◽  
Mean Values ◽  
Flowable Composite ◽  
Dental Sealants ◽  
The Mean ◽  
D Values ◽  
Almost All ◽  
One Way Anova

Abstract Objective This study sought to investigate the toothbrush-dentifrice abrasion of dental sealants. Materials and Methods Weight loss (∆W) and depth loss (∆D) were used as abrasion indicators. Sealant samples from nine products were soaked in dentifrice slurry and abraded by using a toothbrushing machine with a brushing force of 300 g. The mean percentages of ∆W and mean values of ∆D after 24,000 and 48,000 strokes of brushing were compared by using paired t-test. A comparison of these mean values among sealant products was performed by using one-way ANOVA and multiple comparison analysis (Scheffe's test). Results Abrasive wear was observed in all sealants. Teethmate F-1 (Kuraray Noritake, Tokyo, Japan)—a fluoride-releasing unfilled sealant—exhibited the maximum abrasive wear, with ∆W and ∆D values of 1.14% ± 0.37% and 12.84 ± 4.28 µm, respectively. Delton (Dentsply Sirona, Charlotte, North Carolina, United States), a light-cured unfilled sealant, showed the minimum abrasive wear, with ∆W and ∆D values of 0.41% ± 0.09% and 2.93 ± 1.23 µm, respectively. No statistical differences were observed among unfilled sealants except when compared with Teethmate F-1. Similarly, no differences were observed when comparing among filled sealants and flowable composite. Conclusion Abrasive wear occurred in all sealants after brushing with dentifrice. Almost all unfilled sealants showed less wear compared with both filled sealants and flowable composite. However, the low abrasive values of all sealants after brushing with dentifrice implied that there is no clinical significance to this finding.

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 Self-disinfecting Alginate vs Conventional Alginate: Effect on Surface Hardness of Gypsum Cast—An in vitro Study

2017 ◽  
Vol 18 (11) ◽  
pp. 1061-1064 ◽  
Author(s):  
Ajay Nagpal ◽  
Ranjith Madhavan ◽  
Navia George ◽  
Niharika R Thummala ◽  
SV Ravi
Keyword(s):  
Stainless Steel ◽  
Clinical Practice ◽  
Infection Control ◽  
Clinical Significance ◽  
Surface Hardness ◽  
In Vitro Study ◽  
Hardness Testing ◽  
Testing Data ◽  
The Mean

ABSTRACT Introduction For the construction of any dental prosthesis, accurate impressions are necessary. Hence, we undertook the present study to evaluate and compare the surface hardness of gypsum casts poured from impressions made using conventional alginate and self-disinfecting alginate. Materials and methods A total of 30 impressions of stainless steel die were made, out of which 15 impressions were made with conventional alginate and 15 were made with selfdisinfecting alginate and poured using Type III dental stone. Thirty stone specimens were subjected for hardness testing. Data were analyzed using independent samples t-test to compare the mean surface hardness. Results Difference in surface hardness was statistically insignificant (p > 0.05). Conclusion Surface hardness of gypsum casts poured using impressions made from self-disinfecting alginate and conventional alginates were comparable. Clinical significance Self-disinfecting alginates may be employed in clinical practice as safe and effective materials to overcome the infection control issues without compromising on the properties of the material. How to cite this article Madhavan R, George N, Thummala NR, Ravi SV, Nagpal A. Self-disinfecting Alginate vs Conventional Alginate: Effect on Surface Hardness of Gypsum Cast—An in vitro Study. J Contemp Dent Pract 2017;18(11):1061-1064.

scholarly journals In Vitro Study on Bone Heating during Drilling of the Implant Site: Material, Design and Wear of the Surgical Drill

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1921 ◽  
Author(s):  
Juan Carlos Bernabeu-Mira ◽  
Hilario Pellicer-Chover ◽  
Miguel Peñarrocha-Diago ◽  
David Peñarrocha-Oltra
Keyword(s):  
Stainless Steel ◽  
Axial Loading ◽  
In Vitro Study ◽  
Material Design ◽  
Diamond Like Carbon ◽  
Thermal Variation ◽  
Mean Values ◽  
Carbon Coated ◽  
The Mean

Objective: An in vitro study was made to compare mean thermal variation according to the material, design and wear of the surgical drills used during dental implant site preparation. Material and methods: Three study groups (stainless steel drills with straight blades; diamond-like carbon-coated drills with straight blades; and diamond-like carbon-coated drills with twisted blades) were tested to compare material, design and wear of the surgical drill in terms of overall mean values (complete sequence of drills) and specific mean values (each drill separately). The groups comprised four drills: initial, pilot, progressive and final drill. Implant site configuration was performed through an intermittent and gradual drilling technique without irrigation at 800 rpm in standardized synthetic blocks. Maximum axial loading of two kilograms was controlled by an automatic press. Each surgical drill was submitted to 50 drillings and was sterilized every five uses. A thermographic camera analyzed the mean thermal changes. The software-controlled automatic press kept systematic drilling, axial loading and operational speed constant without any human intervention. Student’s t-test, ANOVA and multiple linear regression models were performed. The level of significance was 5% (p = 0.05). Results: The overall mean comparison between the stainless steel and diamond-like carbon-coated materials showed no statistically significant differences (p > 0.05), though specific mean comparison showed statistically significant differences between the drills of the different groups (p < 0.05). The twisted blades exhibited less overall and specific mean thermal variation than straight blades for the progressive and final drills (p < 0.01). In addition, the initial and pilot drills showed a greater mean thermal change than the progressive and final drills. The mean thermal variation was seen to increase during the 50 drillings. Conclusions: Within the limitations of this study, it can be concluded that the drill material did not significantly influence the overall mean thermal variation except for the pilot drill. The drill design affected overall and specific mean thermal variation since the twisted blades heated less than the straight blades. The initial and pilot drills increased the specific mean thermal variation with respect to the progressive and final drills. In addition, all drills in each group produced a gradual increase in mean temperature during the 50 drillings.

scholarly journals Fracture Resistance of Composite Veneers with Different Preparation Designs

2016 ◽  
Vol 20 (2) ◽  
pp. 99-103
Author(s):  
Katerina Zlatanovska ◽  
Ljuben Guguvcevski ◽  
Risto Popovski ◽  
Cena Dimova ◽  
Ana Minovska ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
In Vitro Study ◽  
Fracture Load ◽  
Group 3 ◽  
The Mean ◽  
Group 2 ◽  
Preparation Design ◽  
Frequent Localization ◽  
Group 1

Summary Background: The aim of this in vitro study was to examine the fracture load of composite veneers using three different preparation designs. Material and methods: Fifteen extracted, intact, human maxillary central incisors were selected. Teeth were divided into three groups with different preparation design: 1) feather preparation, 2) bevel preparation, and 3) incisal overlap- palatal chamfer. Teeth were restored with composite veneers, and the specimens were loaded to failure. The localization of the fracture was recorded as incisal, gingival or combined. Results: Composite veneers with incisal overlap - palatal chamfer showed higher fracture resistance compared to feather preparation and bevel preparation. The mean (SD) fracture loads were: Group 1: 100.6±8.0 N, Group 2: 107.4±6.8 N, and Group 3: 122.0±8.8 N. The most common mode of failure was debonding for veneers with feather preparation and fracture when incisal edge is reduced. The most frequent localization of fracture was incisal. Conclusion: The type of preparation has a significant effect on fracture load for composite veneers. This study indicates that using an incisal overlap- palatal chamfer preparation design significantly increases the fracture resistance compared to feather and bevel preparation designs.

scholarly journals Comparative in vitro study of the cleaning efficacy of AirFloss ultra and I-Prox Sulcus brushes in an orthodontic phantom model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hanna Boes ◽  
Sören Brüstle ◽  
Gholamreza Danesh ◽  
Stefan Zimmer ◽  
Mozhgan Bizhang
Keyword(s):  
In Vitro Study ◽  
White Spot Lesions ◽  
Mean Values ◽  
Phantom Model ◽  
Before And After ◽  
Tooth Surfaces ◽  
The Mean ◽  
Post Hoc ◽  
Cleaning Efficacy

AbstractPreventing biofilm-related risks such as gingivitis and white spot lesions during orthodontic treatments is very challenging. The cleaning efficiencies of AirFloss Ultra and I-Prox P sulcus brushes were evaluated using an orthodontic phantom model. After attaching brackets onto black-coated maxillary KaVo teeth, a plaque substitute was applied. The evaluated tooth surfaces were divided into two areas. Cleaning was performed with an AirFloss Ultra with two (A-2) or four (A-4) sprays or an I-Prox P for two (I-2) or four (I-4) seconds. Images before and after cleaning were digitally subtracted, and the percentage of fully cleaned surfaces was determined (Adobe Photoshop CS5, ImageJ). Statistical analysis was performed by ANOVA and post hoc tests with Bonferroni correction (SPSS 25, p < 0.05). The mean values of total cleaning efficacy were 26.87% for I-2, 43.73% for I-4, 34.93%, for A-2 and 56.78% for A-4. The efficacy was significantly higher for A-4 than for A-2, I-4, and I-2. There were significant differences between the four groups. Repeated cleaning led to an improved result. Within the study limitations, the AirFloss Ultra with four sprays proved to be more efficient than the sulcus brush I-Prox P for cleaning.

Effect of Zinc Sulfate on Human Primary Enamel Microhardness: An in vitro Study

2012 ◽  
Vol 36 (4) ◽  
pp. 369-371 ◽  
Author(s):  
M Mirkarimi ◽  
M Bargrizan ◽  
S Eskandarion ◽  
M Shahsavari
Keyword(s):  
Zinc Sulfate ◽  
Artificial Saliva ◽  
In Vitro Study ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Control Group ◽  
Expected Time ◽  
Rich Solution ◽  
The Mean

Objective: The aim of this study was to assess the effect of zinc sulfate on microhardness of human primary enamel. Method: Sixteen sound primary molars were sectioned mesiodistally. For each sample one of the sections was randomly immersed in artificial saliva (Biotene,USA) and the other was immersed in artificial saliva which was charged with 10 mg/5mL concentration of zinc sulfate supplement (Razak Company, Iran) daily. After 24 days (the expected time to use up one 120-mL bottle) the surface microhardness of enamel was measured by knoop hardness test (KH) with Knoop diamond under a 50-gram load for 10 seconds. Results: The mean (± SD) microhardness values (KHV) for the tested groups were 320 ± 49.45 and 357 ± 36.35, respectively. There were statistically significant differences between the groups as exhibited by independent t-test (P=0.023). Conclusion: Primary teeth immersed in a zinc sulfate rich solution for 24 days showed higher microhardness values in comparison with the control group.

scholarly journals Effect of Different Sintering Cycles on the Surface Hardness of Full Contour Monolithic Zirconia – An In Vitro Comparative Study

2021 ◽  
Vol 10 (28) ◽  
pp. 2089-2093
Author(s):  
Sanath Kumar Shetty ◽  
Feba Maria Varghese ◽  
Mohammed Zahid ◽  
Savitha Dandekeri ◽  
Fowzaan Feroz
Keyword(s):  
Surface Hardness ◽  
In Vitro Study ◽  
Group 4 ◽  
Cad Cam ◽  
Monolithic Zirconia ◽  
Group 3 ◽  
Group 2 ◽  
Cycle Group ◽  
Group 1

BACKGROUND This in-vitro study was conducted to compare the effect of different sintering cycles on the surface hardness of full contour monolithic Zirconia. METHODS In this in-vitro study, a total of 28 bar shaped Zirconia samples of final dimensions 20 x 4 x 2 mm were fabricated using Amann Girrbach CAD - CAM unit. These samples were randomly allocated into four groups with 7 samples in each group namely, Group 1, 2, 3 and 4 (Group 1: Long sintering cycle, Group 2: Intermediate sintering cycle, Group 3: Short sintering cycle, Group 4: Ultra-short sintering cycle) and sintered under the respective sintering cycles. The Ceramill® Therm sintering furnace provided 3 sintering cycles ranging from the longest Group - 1 (19 hours), to the short sintering cycle Group - 3 (8 hours), with an intermediate sintering cycle Group - 2 (15hours). The Zircom sintering furnace provided an ultra-short sintering cycle Group - 4 (2 hours). The testing of surface hardness was performed using TECSOL hardness tester. Statistical analysis of the collected data was performed by one - way ANOVA using SPSS software. Multiple comparison was done using post-hoc Tukey’s test. RESULTS One - way ANOVA showed statistically significant difference in the surface hardness of different samples (P < 0.05). The highest mean hardness was observed in Group 3 with 2713.757 + 233.89 VHN, followed by Group 2 with 2595.714 + 62.35 VHN, followed by Group 4 with 2518.600 + 103.65 VHN and Group 1 with the least, 1734.300 + 460.20 VHN. CONCLUSIONS The surface hardness of full contour monolithic Zirconia was influenced to some extent by various sintering cycles. The longest sintering cycle showed the least surface hardness whereas, the short sintering cycle showed the highest surface hardness. Also the ultra-short sintering cycle of 2 hours exhibited surface hardness comparable to the other sintering cycles with longer duration, making it a viable alternative to the conventional sintering cycles. KEY WORDS Monolithic Zirconia, CAD - CAM, Sintering, Hardness

scholarly journals Comparative Evaluation of Marginal Fit of Three Provisional Restorative Materials in Different Mediums: An In-Vitro Study

2021 ◽  
Vol 8 (3) ◽  
pp. 9-14
Author(s):  
Manju Choudhary
Keyword(s):  
Methyl Methacrylate ◽  
Room Temperature ◽  
In Vitro Study ◽  
Marginal Adaptation ◽  
Polymerization Shrinkage ◽  
Mean Values ◽  
Group A ◽  
The Mean ◽  
Group B

Temporaries are used as placeholders before the permanent crowns are installed. If the temporary crown is not fitted properly the tooth can be subject to increased decay and gums can become inflamed causing gingivitis which leads to other more serious problems. A provisional fixed restoration will provide a template for defining tooth contour, esthetics, proximal contacts, ridge contacts and occlusion. Margins made by the indirect technique are considered to be more accurate than those made by the direct technique. The purpose of this in vitro study was to compare the marginal accuracy of provisional crowns made from three different biomaterials using the established indirect method in different environments and to evaluate the effect of water absorption on polymerization shrinkage and the effect of polymerization shrinkage occurring in dry storage for a week. Method:Variables used in this study are: a) Revotek LC-light cured composite b) Protemp II c) poly methyl methacrylate. An aluminium master die was machined with dimensions: 5mm length, 10mm gingival diameter, 5 degree taper, and 1mm shoulder then dental stone die was prepared by making an impression of this experimental model using a poly vinyl siloxane material. Both group A and group B consisted of seven specimens each of DPI, ProtempII, Revotek LC. The specimens were evaluated using measuring microscope (Biolux), which had an eyepiece graticule of 1/10th of an mm. The seven specimens in group A (DPI, ProtempII, Revotek LC) were kept in air at room temperature for one week on the dental stone cast and the readings were tabulated and the mean values were obtained. The seven specimens in group B (DPI, ProtempII, and Revotek LC) were kept in water at room temperature for one week and the readings were tabulated in the same manner and the mean values were obtained. Results: Comparative statistics of the mean values of the specimens kept in air at room temperature showed that DPI had the least marginal discrepancies followed by ProtempII, Revotek LC. The values were highly significant (.002) Comparative statistics of the mean values of the specimens kept in water at room temperature showed that DPI had the least marginal discrepancies followed by Revotek LC, ProtempII. The values were highly significant (.009). Conclusion: After one week in air at room temperature and after one week in water at room temperature DPI recorded the minimal marginal discrepancy. When stored in air at room temperature, DPI had the best marginal adaptation. All of the materials showed evidence of continued polymerization shrinkage after storage in air for a week. Water absorption compensated for polymerization shrinkage in DPI and ProtempII whereas Revotek LC was an exception. Keywords: light cured composite, Protemp II-Bis –acryl composite, poly methyl methacrylate, marginal adaptation, provisional restoration.

scholarly journals The effect of insertion and photopolymerization techniques on microleakage of Class V cavities: a quantitative evaluation

2005 ◽  
Vol 19 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Fabiana Mantovani Gomes França ◽  
Frederico Seidi Hori ◽  
Alex José Souza dos Santos ◽  
José Roberto Lovadino
Keyword(s):  
In Vitro Study ◽  
Root Surface ◽  
Group Iv ◽  
Class V ◽  
Mean Values ◽  
Group Iii ◽  
Soft Start ◽  
Light Curing ◽  
The Mean

The aim of this in vitro study was to evaluate by spectrophotometry the influence of the incremental technique and progressive light curing in the microleakage of Class V cavities. Forty samples were prepared with class V cylindrical cavities on the buccal root surface of bovine incisive teeth and filled with composite resin (Z250). The samples were divided into four groups: I: cavity was bulk filled and the composite was light cured for 40 seconds; Group II: cavity was bulk filled and a "soft-start" polymerization was used; Group III: cavity was filled with the incremental technique in two coats and light cured for 40 seconds; Group IV: cavity was filled with the incremental technique in two coats and light cured with "soft-start" polymerization. After the restoration, the specimens were thermally stressed for 3,000 cycles in bath at 5 ± 2°C and 55 ± 2°C, protected with nail enamel, colored with 2% methylene blue and cut into sections. These sections were triturated and the dye was recovered with PA ethanol and the supernatant was evaluated. The data were submitted to ANOVA and the results showed the following averages: bulk filled and conventional photopolymerization (I) 0.06075 µg/ml; bulk filled and progressive photopolymerization (II) 0.04030 µg/ml; incremental insertion and conventional photopolymerization (III) 0.04648 µg/ml; incremental insertion and progressive photopolymerization (IV) 0.04339 µg/ml. No significant statistic differences were observed among the mean values. The Degulux "soft-start" equipment probably emits too high initial light intensity to promote progressive photopolymerization.

Sign in / Sign up

Export Citation Format

Share Document