Hardness measured with traditional Vickers and Martens hardness methods

Shahdad, Shakeel; McCabe, J.F.; Bull, SJ; Rusby, Sandra; Wassell, Robert

doi:10.1016/j.dental.2006.10.001

Cited by 144 publications

(88 citation statements)

References 22 publications

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“…Similarly IPS-ED demonstrated similar values to the ones given by Bauer & Illie [1]. The differences in HV values might be appended to the different loading conditions (2.94 N compared to 9.8 N) and the possible implication of indentation size effect (ISE), a complication where the hardness testing tends to over-or underestimate Vickers values [17] below a threshold, which is dependent of the material type. Indentation modulus of ZNano was found to be close to the value given by the manufacturer (9 GPa) [11], and IPS-ED to 7.1 given by Bauer & Illie [1].…”

Section: Discussionsupporting

confidence: 53%

“…These two different expressions of the same property were selected for the following reasons: HM is derived by a fully automated procedure overcoming parameters affecting the accuracy of HV (i.e. resolution of optical system, operator's perception, rebound of material around the indentation and others [17], however there is no data for HM in dental literature and thus HV was selected for comparisons with previous studies.…”

Section: Discussionmentioning

confidence: 99%

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Mechanical properties of contemporary orthodontic adhesives used for lingual fixed retention

Sifakakis

Zinelis

Patcas

et al. 2016

Biomedical Engineering / Biomedizinische Technik

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OBJECTIVE The aim of the present study was to test the mechanical properties of different adhesives used in orthodontics for fixed retainers and to investigate their possible interrelations. MA-TERIALS AND METHODS Specimens of six different adhesive resins were prepared: Transbond XT, Transbond LR and an experimental BPA-free orthodontic adhesive, as well as IPS Empress Direct (IPS-ED), ZNano and Accolade. The mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), the ratio of elastic to total work, commonly known as elastic index ( IT) and Vickers hardness (HV). These properties were determined using instrumented indentation testing according to ISO 14577-2002. The results of the aforementioned properties were statistically compared with one-way ANOVA-test and Student-Newman-Keuls multiple comparison test at a=0.05, while possible correlations among the properties tested were analyzed by Pearson correlation. RESULTS Significant differences were identified among all the materials tested for HM, with Transbond LR presenting the highest value. This resin presented the highest EIT too. Significant EIT differences were identified among the materials and only ZNano and IPS-ED showed no significant differences for this property. Transbond LR and ZNano showed higher HV values. ZNano demonstrated the highest elastic index. Pearson analysis showed a strong positive correlation between HM and EIT (0.970), HM and HV (0.837), and EIT and HV (0.695), while a weak negative correlation was found between EIT and elastic index (-0.505). CONCLUSIONS The materials tested demonstrated significant differences in their mechanical properties, and thus differences in their clinical performance are anticipated. Abstract Objective: The aim of the present study was to test the mechanical properties of different adhesives used in orthodontics for fixed retainers and to investigate their possible interrelations. Materials and methods: Specimens of six different adhesive resins were prepared: Transbond XT, Transbond LR and an experimental BPA-free orthodontic adhesive, as well as IPS Empress Direct (IPS-ED), ZNano and Accolade. The mechanical properties tested were Martens hardness (HM), indentation modulus (E IT ), the ratio of elastic to total work, commonly known as elastic index (η IT ) and Vickers hardness (HV). These properties were determined using instrumented indentation testing according to ISO 14577-2002. The results of the aforementioned properties were statistically compared with one-way ANOVA-test and Student-Newman-Keuls multiple comparison test at a = 0.05, while possible correlations among the properties tested were analyzed by Pearson correlation. Results: Significant differences were identified among all the materials tested for HM, with Transbond LR presenting the highest value. This resin presented the highest E IT too. Significant E IT differences were identified among the materials and only ZNano and IPS-ED showed no significant differences for this property. Transbond LR and ZNa...

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Section: Discussionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Mechanical properties of contemporary orthodontic adhesives used for lingual fixed retention

Sifakakis

Zinelis

Patcas

et al. 2016

Biomedical Engineering / Biomedizinische Technik

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“…The second factor contributing to the ISE effect is caused by the properties of the materials. Shahdad et al 28 discussed the ISE effect associated with elastic recovery after indenter removal, and elastic-plastic deformation under the indenter, particularly at low test loads, and that there can be further complications if it occurs in brittle materials. They found that none of the ISE models can be accepted as the best to describe the ISE in different types of materials 10 .…”

Section: Discussionmentioning

confidence: 99%

Effect of indentation load and time on knoop and vickers microhardness tests for enamel and dentin

2009

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The aim of this study was to determine the effect of variations in indentation load and time on the Knoop and Vickers hardness numbers (KHN and VHN) for enamel and dentin. Twenty molar teeth were divided into twenty enamel and twenty dentin specimens. Each specimen was tested using a Knoop or Vickers microhardness tester at different loads and times. The difference in hardness between the groups was analyzed with two-way ANOVA followed by a Tukey test. The results revealed that a difference of indentation time did not influence the microhardness number of enamel and dentin. The KHN values of enamel and the VHN values of dentin were affected by variation of test loads. Therefore, the tooth hardness number for different loads may not be acceptable for comparison.

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“…The indenter displacement of the definite test frame represented the total amount of the elastic deformation of the surface along with the plastic depth of the impression. 30 All specimens were tested 3 times, and the values of HM and E IT were calculated (TestXpert V12.3 Master; Zwick) with the following equations (DIN EN ISO 14577) 35 : and Descriptive statistics were calculated, and the normality of data distribution was tested using the Kolmogorov-Smirnov and Shapiro-Wilk test. The Levene test was used to evaluate the assumption of variances' homogeneity.…”

Section: Methodsmentioning

confidence: 99%

“…5,28 Martens hardness enables a physicomechanical characterization of the local mechanical properties of materials, including the elastic and plastic parts under different loading regimens. 29,30 Most of the available studies, however, only determined the reduced mechanical properties of resins after aging in artificial saliva, alcohol, and distilled water. 31,32 To date, only limited information is available on the long-term behavior of contemporary polymers such as PEEK with regard to different aging regimens.…”

Section: Introductionmentioning

confidence: 99%

Physicomechanical characterization of polyetheretherketone and current esthetic dental CAD/CAM polymers after aging in different storage media

Liebermann

Wimmer

Schmidlin

et al. 2016

The Journal of Prosthetic Dentistry

165

126

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STATEMENT OF PROBLEM: Polyetheretherketone (PEEK) can be used to support fixed dental prostheses. However, information about physicomechanical characterization is still scarce. PUR-POSE: The purpose of this in vitro study was to assess effects of different aging regimens/durations on roughness, solubility, water absorption, Martens hardness (HM), and indentation modulus/EIT on different computer-aided design and computer-aided manufacturing (CAD/CAM) polymers. MATERIAL AND METHODS: Forty standardized specimens of the following materials were fabricated: PEEK: Dentokeep (DK); hybrid material: VITA Enamic (EN); composite resins: LAVA Ultimate (LU) and an experimental CAD/CAM nanohybrid-composite resin (EX); poly(methyl methacrylate) (PMMA)-based: VITA CAD-Temp (CT); Telio CAD (TC), artBloc Temp (AT), and ZENOTEC ProFix (ZP). A nanofilledpolymer for interim restorations, Protemp 4 (CG), served as the control group. Specimens were stored in sodium chloride, artificial saliva, physiological saliva, and distilled water at 37°C for 1, 7, 14, 28, 90, and 180 days. Roughness, water absorption, HM, and EIT were investigated after each storage period; solubility was determined after 180 days only. Data were analyzed using weighted 3/2/1-way ANOVA and the post hoc Scheffé tests (=.05). RESULTS: Storage media had no effect on surface roughness and water absorption. Physiological saliva revealed the highest significant impact on solubility followed by artificial saliva, sodium chloride, and distilled water. Water absorption increased significantly with storage duration. PEEK showed the lowest solubility and water absorption values. The highest solubility was observed for the conventional polymer CG, and the highest water absorption was found for the composite LU. PMMA-based TC, ZP, CG, and AT showed the lowest HM and indentation modulus, followed by CT, and PEEK. The highest values were observed for the hybrid material EN, followed by LU and EX. CONCLUSIONS: The hardness parameters of PEEK were comparable with those of PMMA-based materials. group. Specimens were stored in sodium chloride, artificial saliva, physiological saliva, and distilled water at 37°C for 1, 7, 14, 28, 90, and 180 days. Roughness, water absorption, HM, and E IT were investigated after each storage period; solubility was determined after 180 days only. Data were analyzed using weighted 3/2/1-way ANOVA and the posthoc Scheffé tests (α=05).Results. Storage media had no effect on surface roughness and water absorption.Physiological saliva revealed the highest significant impact on solubility followed by artificial saliva, sodium chloride, and distilled water. Water absorption increased significantly with storage duration. PEEK showed the lowest solubility and water absorption values. The highest ! ! ! 2! solubility was observed for the conventional polymer CG, and the highest water absorption was found for the composite LU. PMMA-based TC, ZP, CG, and AT showed the lowest HM and indentation modulus, followed by CT, and PEEK. The highest values were ...

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Hardness measured with traditional Vickers and Martens hardness methods

Cited by 144 publications

References 22 publications

Mechanical properties of contemporary orthodontic adhesives used for lingual fixed retention

Mechanical properties of contemporary orthodontic adhesives used for lingual fixed retention

Effect of indentation load and time on knoop and vickers microhardness tests for enamel and dentin

Physicomechanical characterization of polyetheretherketone and current esthetic dental CAD/CAM polymers after aging in different storage media

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