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Youm JH, Jeong IJ, Kwon JS, Lim BS, Oh MH, Kim KM. The optical property measuring methods for resin composite using multiple spectrophotometers. Dent Mater J 2024:2023-312. [PMID: 38825450 DOI: 10.4012/dmj.2023-312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
This study aimed to propose the measurement methods for resin composite translucency using four shades of resin composite and four spectrophotometers. Four methods were used for measuring translucency: (A) color measurement using reflectance mode, (B) visible light spectrum measurement using reflectance mode, (C) color measurement using transmittance mode, (D) visible light spectrum measurement using transmittance mode. Although there was a significant difference among the results of the translucency measuring methods, the same tendency was observed for translucency parameters obtained using each spectrophotometer. Therefore, the four methods can potentially be used as translucency measuring methods for resin composite.
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Affiliation(s)
- Ji-Hun Youm
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry
- BK21 FOUR Project, Yonsei University College of Dentistry
| | - Il Jun Jeong
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry
| | - Jae-Sung Kwon
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry
- BK21 FOUR Project, Yonsei University College of Dentistry
| | - Bum-Soon Lim
- Department of Dental Biomaterials Science, School of Dentistry and Dental Research Institute, Seoul National University
| | | | - Kwang-Mahn Kim
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry
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Liu S, El-Angbawi A, Ji R, Rosa V, Silikas N. Optical effects of graphene addition on adhesives for orthodontic lingual retainers. Eur J Oral Sci 2024; 132:e12966. [PMID: 38062539 DOI: 10.1111/eos.12966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 11/18/2023] [Indexed: 01/25/2024]
Abstract
The objective of this study was to determine the effects on the colour of adding increasing concentrations of graphene to orthodontic fixed retainer adhesives and to evaluate changes in optical transmission during light curing and the resultant degree of conversion. Two different types of adhesives commonly used for fixed retainers were investigated: A packable composite (Transbond) and a flowable composite (Transbond Supreme). Graphene was added to the adhesives in three different concentrations (0.01, 0.05, and 0.1 wt%). Adhesives without graphene addition were set as control groups. A Minolta colourimeter was used to measure the colour and translucency parameters. Irradiance transmitted during curing was quantified using MARC Light Collector. Fourier-transform infrared spectroscopy was used to record degree of conversion. Data were statistically analysed with the Student's t-test and one-way ANOVA with Tukey's tests (α = 0.05). The findings showed that incorporating graphene darkened the adhesive colour significantly and reduced translucency. As the graphene concentration reached 0.1 wt%, samples became opaque; yet, no adverse effect on degree of conversion was observed. The addition of graphene reduces optical transmission of lingual retainer adhesives; the effect increases with graphene concentration.
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Affiliation(s)
- Shiyao Liu
- Dentistry, University of Manchester, Manchester, UK
| | | | - Ruidong Ji
- Department of Physics and Astronomy & Photon Science Institute, University of Manchester, Manchester, UK
| | - Vinicius Rosa
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore, Singapore
- Faculty of Dentistry, National University of Singapore, Singapore, Singapore
- Oral Care Health Innovations and Designs Singapore, National University of Singapore, Singapore, Singapore
| | - Nick Silikas
- Dentistry, University of Manchester, Manchester, UK
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Chaharmahali R, Ghaemi A, Molayi M. Influence of Monowave and Polywave LED Unites on G-Aenial Resin Composites’ Polymerization: An In Vitro Study. DENTAL HYPOTHESES 2022. [DOI: 10.4103/denthyp.denthyp_156_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Diab RA, Yap AU, Gonzalez MAG, Yahya NA. Impact of light-curing distance on the effectiveness of cure of bulk-fill resin-based composites. Saudi Dent J 2021; 33:1184-1189. [PMID: 34916770 PMCID: PMC8665223 DOI: 10.1016/j.sdentj.2021.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 11/25/2022] Open
Abstract
Objective To investigate the effect of light-curing distance on the effectiveness of cure (EC) of bulk-fill resin-based composites (RBCs). Materials and methods Two bulk-fill RBCs (a Tetric N-Ceram Bulk Fill (TN) and a Filtek Bulk Fill (FK)) are evaluated. Specimens (4 mm high) are cured for 20 s at different distances (0 mm (D0), 2 mm (D2), 4 mm (D4), 6 mm (D6) and 8 mm (D8)) and stored for 24 h in 100% relative humidity at 37 °C. The top and bottom surface hardness (SH) (n = 12) are assessed using a Knoop microhardness tester and the EC is calculated. The EC is characterized by the hardness ratio (HR) (mean bottom: top SH). An HR of 0.8 is used as the benchmark for an effective/adequate cure. Data are analyzed using one-way analysis of variance and Tukey’s post hoc test (α = 0.05). Correlations between the top and bottom surfaces are examined using the Pearson correlation (α = 0.05). Results For the TN, the HR at D8 is significantly lower than all other light-curing distances, while for the FK, it is significantly lower than D0 only. Conclusion The effect of light-curing distance on the EC of bulk-fill RBCs is material dependent. Notwithstanding the light-curing distance, the EC of the FK and TN is below the threshold HR value of 0.8 when photopolymerized for 20 s in 4 mm increments in black opaque molds.
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Affiliation(s)
- Rana Abdelbaset Diab
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Adrian Ujin Yap
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.,Department of Dentistry, Ng Teng Fong General Hospital and Faculty of Dentistry National University of Singapore, National University Health System, Singapore.,National Dental Research Institute Singapore, National Dental Centre Singapore and Duke-NUS Medical School, Singapore Health Services, Singapore
| | | | - Noor Azlin Yahya
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
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TEKBAŞ ATAY M, BÜYÜKGÖZE DİNDAR M, OZVEREN N. EFFECT OF DISPOSABLE SHEATHS ON THE VICKERS MICROHARDNESS OF RESIN COMPOSITES. CLINICAL AND EXPERIMENTAL HEALTH SCIENCES 2021. [DOI: 10.33808/clinexphealthsci.752555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Pratap B, Gupta RK, Bhardwaj B, Nag M. Resin based restorative dental materials: characteristics and future perspectives. JAPANESE DENTAL SCIENCE REVIEW 2019; 55:126-138. [PMID: 31687052 PMCID: PMC6819877 DOI: 10.1016/j.jdsr.2019.09.004] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/13/2019] [Accepted: 09/19/2019] [Indexed: 01/27/2023] Open
Abstract
This review article compiles the characteristics of resin based dental composites and an effort is made to point out their future perspectives. Recent research studies along with few earlier articles were studied to compile the synthesis schemes of commonly used monomers, their characteristics in terms of their physical, mechanical and polymerization process with selectivity towards the input parameters of polymerization process. This review covers surface modification processes of various filler particles using silanes, wear behaviour, antimicrobial behaviour along with its testing procedures to develop the fundamental knowledge of various characteristics of resin based composites. In the end of this review, possible areas of further interests are pointed out on the basis of literature review on resin based dental materials.
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Key Words
- 4-EDMAB, Ethyl-4-dimethyl amino benzoate
- Antimicrobial properties
- BPA, Bisphenol-A
- BPO, Benzoyl peroxide
- Bis-EMA, Ethoxylatedbisphenol-A-dimethacrylate
- Bis-GMA, Bisphenol A-glycidyl methacrylate
- CQ, Camphorquinone
- DC, Degree of conversion
- DHEPT, Dihydroxy ethyl-para-toluidine
- DMAEMA, Dimethyl amino ethyl methacrylate
- DMAP, Dimethyl amino pyridine
- Dental composites
- EGDMA, Ethylene glycol dimethacrylate
- HEMA, 2-Hydroxyethyl methacrylate
- LED, Light emitting diode
- PPD, 1-phenyl-1,2 propanedione
- PS, Polymerization Shrinkage
- RBCs, Resin based composites
- Self-healing
- Surface modification of filler particles
- TEG, Triethylene glycol
- TEGDMA, Triethylene glycol dimethacrylate
- TPO, Diphenyl phosphine oxide
- UDMA, Urethane dimethacrylate
- Wear
- γ-MPS, 3-(Trimethoxysilyl) Propyl Methacrylate
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Affiliation(s)
- Bhanu Pratap
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, India
| | - Ravi Kant Gupta
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, India
| | | | - Meetu Nag
- Department of Mechatronics Engineering, Manipal University Jaipur, Jaipur, India
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Stencel R, Kasperski J, Pakieła W, Mertas A, Bobela E, Barszczewska-Rybarek I, Chladek G. Properties of Experimental Dental Composites Containing Antibacterial Silver-Releasing Filler. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E1031. [PMID: 29912158 PMCID: PMC6025467 DOI: 10.3390/ma11061031] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 06/11/2018] [Accepted: 06/11/2018] [Indexed: 12/19/2022]
Abstract
Secondary caries is one of the important issues related to using dental composite restorations. Effective prevention of cariogenic bacteria survival may reduce this problem. The aim of this study was to evaluate the antibacterial activity and physical properties of composite materials with silver sodium hydrogen zirconium phosphate (SSHZP). The antibacterial filler was introduced at concentrations of 1%, 4%, 7%, 10%, 13%, and 16% (w/w) into model composite material consisting of methacrylate monomers and silanized glass and silica fillers. The in vitro reduction in the number of viable cariogenic bacteria Streptococcus mutans ATCC 33535 colonies, Vickers microhardness, compressive strength, diametral tensile strength, flexural strength, flexural modulus, sorption, solubility, degree of conversion, and color stability were investigated. An increase in antimicrobial filler concentration resulted in a statistically significant reduction in bacteria. There were no statistically significant differences caused by the introduction of the filler in compressive strength, diametral tensile strength, flexural modulus, and solubility. Statistically significant changes in degree of conversion, flexural strength, hardness (decrease), solubility (increase), and in color were registered. A favorable combination of antibacterial properties and other properties was achieved at SSHZP concentrations from 4% to 13%. These composites exhibited properties similar to the control material and enhanced in vitro antimicrobial efficiency.
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Affiliation(s)
- Robert Stencel
- Private Practice, Center of Dentistry and Implantology, ul. Karpińskiego 3, 41-500 Chorzów, Poland.
| | - Jacek Kasperski
- Department of Prosthetic Dentistry, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, pl. Akademicki 17, 41-902 Bytom, Poland.
| | - Wojciech Pakieła
- Faculty of Mechanical Engineering, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland.
| | - Anna Mertas
- Chair and Department of Microbiology and Immunology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia in Katowice, ul. Jordana 19, 41-808 Zabrze, Poland.
| | - Elżbieta Bobela
- Chair and Department of Microbiology and Immunology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia in Katowice, ul. Jordana 19, 41-808 Zabrze, Poland.
| | - Izabela Barszczewska-Rybarek
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, 44-100 Gliwice, Poland.
| | - Grzegorz Chladek
- Faculty of Mechanical Engineering, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland.
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Effect of different beverages on the color stability and microhardness of CAD/CAM hybrid versus feldspathic ceramic blocks: An in-vitro study. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.fdj.2017.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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AlShaafi MM. Factors affecting polymerization of resin-based composites: A literature review. Saudi Dent J 2017; 29:48-58. [PMID: 28490843 PMCID: PMC5411902 DOI: 10.1016/j.sdentj.2017.01.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/28/2017] [Accepted: 01/29/2017] [Indexed: 11/15/2022] Open
Abstract
AIM The aim of this review was to help clinicians improve their understanding of the polymerization process for resin-based composites (RBC), the effects of different factors on the process and the way in which, when controlled, the process leads to adequately cured RBC restorations. METHODS Ten factors and their possible effects on RBC polymerization are reviewed and discussed, with some recommendations to improve that process. These factors include RBC shades, their light curing duration, increment thickness, light unit system used, cavity diameter, cavity location, light curing tip distance from the curing RBC surface, substrate through which the light is cured, filler type, and resin/oral cavity temperature. CONCLUSION The results of the review will guide clinicians toward the best means of providing their patients with successfully cured RBC restorations.
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Affiliation(s)
- Maan M AlShaafi
- Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
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Akan E. Influence of shade of adhesive resin cement on its polymerization shrinkage. BIOTECHNOL BIOTEC EQ 2016. [DOI: 10.1080/13102818.2016.1147983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Ender Akan
- Faculty of Dentistry, Department of Prosthodontics, Izmir Katip Celebi University, Izmir, Turkey
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Theodoridis M, Dionysopoulos D, Koliniotou-Koumpia E, Dionysopoulos P, Gerasimou P. Effect of preheating and shade on surface microhardness of silorane-based composites. ACTA ACUST UNITED AC 2016; 8. [PMID: 26748834 DOI: 10.1111/jicd.12204] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/31/2015] [Indexed: 11/29/2022]
Abstract
AIM The aim of the present study was to evaluate the effect of preheating and shade on the surface microhardness of silorane-based composites. METHODS Three shades of two different types of composites were evaluated: a silorane-based composite and a methacrylate-based composite. The composites were tested at 23°C, and after preheating at 55°C. Five specimens were prepared for each experimental group. The top surface of the specimens was irradiated for 20 s using an LED unit. Vickers microhardness test was used to evaluate both top and bottom surfaces of the specimens, followed by 24-h storage in the dark. Statistical analysis was performed using one-way anova and Tukey's post-hoc test at a level of significance of α = 0.05. RESULTS There was a significant rise in microhardness as the temperature increased from 23 to 55°C for both the top and bottom surfaces of the tested composites (P < 0.05). The C2 shade of both composites exhibited the lowest microhardness (P < 0.05), while the A2 and A3 shades did not show significant differences compared to each other (P > 0.05) Filtek Silorane presented significantly lower microhardness than Filtek Z250 (P < 0.05), regardless of the temperature, shade, or depth of measurement. CONCLUSIONS Preheating, shade, and composition of the tested composite resins affected their surface microhardness.
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Affiliation(s)
- Marios Theodoridis
- Department of Operative Dentistry, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Dimitrios Dionysopoulos
- Department of Operative Dentistry, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Eugenia Koliniotou-Koumpia
- Department of Operative Dentistry, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Pavlos Dionysopoulos
- Department of Operative Dentistry, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Paris Gerasimou
- Department of Operative Dentistry, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Mousavinasab SM, Barekatain M, Sadeghi E, Nourbakhshian F, Davoudi A. Evaluation of light curing distance and mylar strips color on surface hardness of two different dental composite resins. Open Dent J 2014; 8:144-7. [PMID: 25228939 PMCID: PMC4160846 DOI: 10.2174/1874210601408010144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/28/2014] [Accepted: 07/01/2014] [Indexed: 11/22/2022] Open
Abstract
Introduction: Hardness is one of the basic properties of dental materials, specially composite resins which is relevant to their polymerization. The aim of this study was to evaluate the effect of light curing distance and the color of clear Mylar strips on surface hardness of Silorane-based (SCR) and Methacrylate-based composite resins (MCR). Materials and methods: 40 samples of MCRs (Filtek Z250) and SCRs (Filtek P90) were prepared in size of 5 mm×2 mm (80 samples in total). The samples divided into 8 groups (10 samples in each one) based on the color of clear Mylar strips (white or blue) and distance from light curing source (0 mm or 2 mm). All the samples cured for 40 second and stored in incubator for 24 hours in 37°C temperature. Surface hardness test was done by Vickers test machine and the collected data were analyzed by one-way ANOVA and paired T-test by using SPSS software version 13 at significant level of 0.05. Results: MCRs cured with blue Mylar strips from 0 mm distance had the highest (114.5 kg/mm2) and SCRs cured with white Mylar strips from 2 mm distance had the lowest (42.2 kg/mm2) mean of surface hardness. Also, the results of comparison among SCRs and MCRs showed significant differences among all groups (all P values <0.01). Conclusion: The hardness decreased as the distance increased and the blue Mylar strips provided higher hardness than clear ones. Also, Filtek Z250 showed higher hardness compared to Filtek P90.
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Affiliation(s)
- Seyed Mostafa Mousavinasab
- Restorative Dentistry Department, Torabinejad Dental Research Center and Dental Materials Research Center, School of Dentistry, Isfahan University of Medical Sciences and Islamic Azad University (Khorasgan branch), Isfahan, Iran
| | - Mehrdad Barekatain
- Restorative Dentistry Department, Islamic Azad University (Khorasgan branch), Isfahan, Iran
| | - Elahe Sadeghi
- Graduated Dentistry Student, Islamic Azad University (Khorasgan branch), Isfahan, Iran
| | - Farzaneh Nourbakhshian
- Dentistry Student, Dental Students Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfa-han, Iran
| | - Amin Davoudi
- Dentistry Student, Dental Students Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfa-han, Iran
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LEE SK, KIM TW, SON SA, PARK JK, KIM JH, KIM HI, KWON YH. Influence of light-curing units on the polymerization of low-shrinkage composite resins. Dent Mater J 2013; 32:688-94. [PMID: 24088822 DOI: 10.4012/dmj.2013-027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Passos SP, Kimpara ET, Bottino MA, Santos GC, Rizkalla AS. Effect of ceramic shade on the degree of conversion of a dual-cure resin cement analyzed by FTIR. Dent Mater 2012; 29:317-23. [PMID: 23261020 DOI: 10.1016/j.dental.2012.11.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 07/11/2012] [Accepted: 11/15/2012] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The aim of this research was to evaluate the degree of monomer conversion of different resin cement shades when photocured under different feldspathic ceramic shades. The photocuring time was also evaluated as well as the translucency of each ceramic shade. METHODS Three VITA VM7 ceramic shades (Base Dentin 0M1, Base Dentin 2M2 and Base Dentin 5M3) were used to determine the translucency percentage. A spectrophotometer MiniScan was used to measure the opacity percentage of each specimen (2-mm-thick) and then the translucency was calculated. To measure the degree of conversion (DC), the resin cement (Variolink II; A3 Yellow and transparent) specimens (thickness: 100 μm) were photocured under a ceramic block (2-mm-thick) for 20 or 40s. Specimens photocured without the ceramic block were used as control. Sixteen groups (n=3) were evaluated. Micro-ATR/FTIR spectrometry was used to evaluate the extent of polymerization of all specimens after 24h. The %DC was calculated of experimentally polymerized versus maximally polymerized composite. RESULTS The translucency percentages of 0M1, 2M2 and 5M3 ceramics were 12.41 (1.02)%, 5.75 (1.91)% and 1.07 (0.03)%, respectively. The %DC of both resin cement shades cured under ceramic 5M3 was significantly lower than the other groups (p<0.05). The %DC of 0M1 groups exhibited no significant difference from 2M2 groups (p>0.05), with the exception of the transparent cement photocured for 40s. CONCLUSION Photocuring under 2mm ceramic showed that the increase in chroma saturation significantly decreased Variolink II resin cement %DC (100-μm-thick).
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Affiliation(s)
- Sheila P Passos
- Department of Dentistry, University of Alberta, Edmonton, Alberta, Canada.
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Poorsattar Bejeh Mir A, Poorsattar Bejeh Mir M. How does duration of curing affect the radiopacity of dental materials? Imaging Sci Dent 2012; 42:89-93. [PMID: 22783477 PMCID: PMC3389055 DOI: 10.5624/isd.2012.42.2.89] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 03/30/2012] [Accepted: 04/19/2012] [Indexed: 11/30/2022] Open
Abstract
Purpose Clinicians commonly encounter cases in which it is difficult to determine whether adjacent radiopacities are normal or pathologic. The ideal radiopacity of composite resin is equal to or higher than that of the same thickness of aluminum. We aimed to investigate the possible effects of different curing times on the post-24-hour radiopacity of composite resins on digital radiographs. Materials and Methods One mm thick samples of Filtek P60 and Clearfil resin composites were prepared and cured with three regimens of continuous 400 mW/cm2 irradiance for 10, 20 and 30 seconds. Along with a 12-step aluminum step wedge, digital radiographs were captured and the radiopacities were transformed to the equivalent aluminum thicknesses. Data were compared by a general linear model and repeated-measures of ANOVA. Results Overall, the calculated equivalent aluminum thicknesses of composite resins were increased significantly by doubling and tripling the curing times (F(2,8)=8.94, p=0.002). Notably, Bonferroni post-hoc tests confirmed that the radiopacity of the cured Filtek P60 was significantly higher at 30 seconds compared with 10 seconds (p=0.04). Although the higher radiopacity was observed by increasing the time, other comparisons showed no statistical significance (p>0.05). Conclusion These results supported the hypothesis that the radiopacity of resin composites might be related to the duration of light curing. In addition to the current standards for radiopacity of digital images, defining a standard protocol for curing of dental materials should be considered, and it is suggested that they should be added to the current requirements for dental material.
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Affiliation(s)
- Arash Poorsattar Bejeh Mir
- Dentistry Student Research Committee (DSRC), Dental Materials Research Center, Dentistry School, Babol University of Medical Sciences, Babol, Iran
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Poorsattar Bejeh Mir A, Poorsattar Bejeh Mir M. The effect of different curing time regimens on immediate postpolymerization color changes of resin composites. J Contemp Dent Pract 2012; 13:472-475. [PMID: 23151695 DOI: 10.5005/jp-journals-10024-1171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
AIM Light curing of resin composites may considerably change the color of resin composites. The aim of this study was to evaluate the changing pattern of resin composite's color by different curing times. MATERIALS AND METHODS Fifteen, 1 mm-thick, samples of each A2 shade Clearfill and Filtek P60 composites were prepared. First five samples were cured for 10s (400 mW/cm2) in each pole of the rectangular samples (right upper, right lower, left lower, left upper plus central zone). Consecutive sets of samples, each consists of five, were irradiated by doubling and tripling the curing time to 20 and 30s. Color change were measured by means of CIE 1976 L*a*b system equation (ΔE) for each digitalized picture of the corresponding sample. RESULTS Color of samples was clinically significant changed by increasing the curing time from 10 to 20s and from 20 to 30s for Clearfil (ΔE = 13.86 and 14.11 respectively,) and Filtek P60 (ΔE = 7.68 and 11.66 respectively). The 'b' component change was responsible for the most color alteration confirmed by the linear regression model (p < 0.001). CONCLUSION This study revealed the contrasting pattern of resin composite's color change with the different curing times. Our findings support that light curing is accompanied by a higher attained blue chroma and diminished yellowness of resin composites. CLINICAL SIGNIFICANCE A complete and proper curing of sample resin composites on buccal surface of particular tooth, as a common practice to ensure the maximize concordance composite and tooth color, is reassured according to the considerable differences of undercured and overcured in comparison to normocured composite.
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Affiliation(s)
- Arash Poorsattar Bejeh Mir
- Department of Student Research Committee, Dental Materials Research Center, Dentistry School, Babol University of Medical Sciences, Ganj Afrooz Ave, Babol, Mazandaran, Iran.
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Creep deformation of restorative resin-composites intended for bulk-fill placement. Dent Mater 2012; 28:928-35. [PMID: 22656273 DOI: 10.1016/j.dental.2012.04.038] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 04/30/2012] [Accepted: 04/30/2012] [Indexed: 10/28/2022]
Abstract
OBJECTIVES To determine the creep deformation of several "bulk-fill" resin-composite formulations in comparison with some other types. METHODS Six resin-composites; four bulk-fill and two conventional were investigated. Stainless steel split molds (4 mm × 6 mm) were used to prepare cylindrical specimens for creep testing. Specimens were thoroughly irradiated with 650 mW cm(-2). A total of 10 specimens for each material were divided into two groups (n = 5) according to the storage condition; Group A stored dry at 37 °C for 24h and Group B stored in distilled water at 37 °C in an incubator for 24h. Each specimen was loaded (20 MPa) for 2h and unloaded for 2h. The strain deformation was recorded continuously for 4h. Statistical analysis was performed using a two-way ANOVA followed by one-way ANOVA and the Bonferroni post hoc test at a significance level of a = 0.05. RESULTS The maximum creep strain % ranged from 0.72% up to 1.55% for Group A and the range for Group B increased from 0.79% up to 1.80% due to water sorption. Also, the permanent set ranged from 0.14% up to 0.47% for Group A and from 0.20% up to 0.59% for Group B. Dependent on the material and storage condition, the percentage of creep strain recovery ranged between 64% and 81%. Increased filler loading in the bulk-fill materials decreased the creep strain magnitude. SIGNIFICANCE Creep deformation of all studied resin-composites increased with wet storage. The "bulk-fill" composites exhibited an acceptable creep deformation and within the range exhibited by other resin-composites.
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Resin-composite cytotoxicity varies with shade and irradiance. Dent Mater 2012; 28:312-9. [PMID: 22240279 DOI: 10.1016/j.dental.2011.12.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 11/21/2011] [Accepted: 12/12/2011] [Indexed: 11/22/2022]
Abstract
OBJECTIVES The study was aimed at investigating the cytotoxicity of different composites as a function of composite shade and the light curing unit (LCU) employed. METHODS Non-polymerized and polymerized samples of the composites Grandio(®) (VOCO, Cuxhaven), Solitaire(®) (Heraeus Kulzer, Hanau) and Filtek Z 250(®) (3M/Espe, Seefeld) in two markedly differing shades (A2, C2) were prepared. Polymerization was performed with two LCUs: Heliolux II (Ivoclar/Vivadent, Ellwangen) and Swiss Master Light (EMS, Nyon, Switzerland). To obtain composite extracts, the samples were immersed in cell culture medium (DMEM--Dulbecco's Modified Eagle Medium), which was replaced daily up to the 7th day of the experiment, and then on the 14th, 21st and 28th day. After incubation of human gingival fibroblasts (HGF) with the extracts obtained, cytotoxicity was determined using the MTT test. RESULTS With the non-polymerized samples, essentially no influence of the composite shades investigated on HGF viability was detected, with the exception of the Solitaire material, where a higher cytotoxicity of the shade C2 in the non-polymerized state was found at the end of the observation period. After polymerization of the different composites, the cytotoxic reaction observed for the extracts of shade C2 was stronger than that observed for A2. After polymerization with the Heliolux II (HLX) LCU, the extracts of composites Grandio and Solitaire C2 were significantly more toxic than those of the A2 shade (p<0.01). Polymerization with the Swiss Master Light (SML) reduces this cytotoxic effect. The extracts of the Grandio composite showed the least cytotoxic effect throughout the observation period, irrespective of the LCU used. For the extracts of the Z250 specimens, the cytotoxicity observed was generally higher. SIGNIFICANCE The results show that the shade of the composite has an influence on its cytotoxicity and that this cytotoxicity is also influenced by the light curing unit used. It was observed that composites of the darker shade (C2) had a higher cytotoxicity, which varied with the LCU employed.
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