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Pyszka I, Jędrzejewska B. Highly Efficient Photoinitiation Systems Based on Dibenzo[a,c]phenazine Sensitivity to Visible Light for Dentistry. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2597. [PMID: 38893862 PMCID: PMC11173425 DOI: 10.3390/ma17112597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 05/20/2024] [Accepted: 05/25/2024] [Indexed: 06/21/2024]
Abstract
In this work, photoinitiation systems based on dibenzo[a,c]phenazine sensitivity to visible light were designed for their potential application in dentistry. Modification of the structure of dibenzo[a,c]phenazine consisted of introducing electron-donating and electron-withdrawing substituents and heavy atoms into position 11. The synthesized compounds are able to absorb radiation emitted by dental lamps during photoinitiation of the polymerization process. In the presence of acrylates, dibenzo[a,c]phenazines show excellent photoinitiating abilities in systems containing an electron donor or a hydrogen-atom donor as a second component. The developed systems initiate the polymerization process comparable to a commercial photoinitiator, i.e., camphorquinone. Moreover, the performed studies showed a significant shortening of the polymerization time and a reduction in the amount of light absorber. This indicates that polymeric materials are obtained at a similar rate despite a significant reduction in the concentration of the newly developed two-component photoinitiating systems.
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Affiliation(s)
- Ilona Pyszka
- Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, ul. Seminaryjna 3, 85-326 Bydgoszcz, Poland
| | - Beata Jędrzejewska
- Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, ul. Seminaryjna 3, 85-326 Bydgoszcz, Poland
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Alfares R, Agha A, Jabour O. Temperature Changes in Primary and Permanent Teeth Dentine of Varying Thicknesses Following Irradiation by Two Light Curing Units. Cureus 2023; 15:e44029. [PMID: 37746354 PMCID: PMC10517433 DOI: 10.7759/cureus.44029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2023] [Indexed: 09/26/2023] Open
Abstract
AIM This study was performed to determine the temperature rise under human dentin discs of different thicknesses from primary and permanent teeth during the photo-curing process using quartz tungsten halogen (QTH) or light-emitting diode (LED). MATERIALS AND METHODS The current experimental study sample consisted of 160 dentin discs of different thicknesses (0.5, 1, 1.5, and 2 mm), of which 80 dentin discs were prepared from sound lower second primary molars, and the remaining 80 dentin discs were prepared from sound lower third permanent molars extracted surgically for various reasons. A "K" type of thermal tentacle was placed in the center of an acrylic resin base, followed by the placement of a dentin disc. Then, the thermal changes were measured during the photo-curing of the composite using a second LED or QTH light curing unit for 20 s. Statistical evaluation was performed using the IBM SPSS Statistics® Version 20.0 software system (SPSS Inc., Chicago, IL, USA). RESULTS The current study found that the temperature rise in primary teeth (1.17-2.96°C) is significantly lower compared to the rise in permanent teeth (1.55-3.33°C), regardless of the dentin disc thickness or light curing unit used. The temperature rise decreases significantly when the thickness of dentin discs increases, regardless of the type of teeth or light curing unit used (P<0.05). Furthermore, QTH causes less temperature rise (1.17-2.65°C) compared to LED (1.61-3.33°C). CONCLUSIONS The temperature rise during polymerization of the resin composite with the second-generation LED appeared to be below 5.5°C. Hence, it appears to be safe for use during the restoration of primary teeth. Primary teeth dentin might be more effective than permanent teeth dentin in protecting the dental pulp.
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Affiliation(s)
- Reem Alfares
- Pediatric Dentistry, University of Hama, Hama, SYR
| | - Amani Agha
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, GBR
| | - Obada Jabour
- Pediatric Dentistry, University of Hama, Hama, SYR
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Watts DC. Light-curing dental resin-based composites: How it works and how you can make it work. FRONTIERS IN DENTAL MEDICINE 2023. [DOI: 10.3389/fdmed.2023.1108316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
AimClinicians may become quite familiar with the rapid transformation of composite pastes to rigid solids, as a routine phenomenon in operative dentistry. But they may still lack scientific understanding of how and why this happens. Efforts to learn scientifically about the interaction between light beams and resin-composites can significantly promote effective clinical placement of restorations. Neglect of such study can result in practical procedures of light-curing that are inadequate or even seriously defective.MethodThis review addresses the underlying science and technology to elucidate how light curing works, for dental resin-based composites, including—but not limited to—bulk fill types. This involves questions concerning: (a) the particle-wave understanding of light; (b) how photons can penetrate sufficiently deeply into bulk fill composites; (c) the necessary technology of LED light-curing units (LCUs); (d) the criteria for absorption of photons by photo initiators to initiate free-radical addition polymerisation.ConclusionsThe implications for clinical practice are surveyed. These include design variables and selection criteria for LED-LCUs and guidelines on their use. This is to guide practitioners towards safe and effective light-curing procedures so that they can achieve optimal result for their patients.
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Photoinitiation abilities of indeno- and indoloquinoxaline derivatives and mechanical properties of dental fillings based on multifunctional acrylic monomers and glass ionomer. POLYMER 2022. [DOI: 10.1016/j.polymer.2022.125625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Sulaiman TA, Suliman AA, Mohamed EA, Rodgers B, Altak A, Johnston WM. Mechanical Properties of Bisacryl-, Composite-, and Ceramic-resin Restorative Materials. Oper Dent 2022; 47:97-106. [PMID: 35029680 DOI: 10.2341/20-191-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Resin-based materials used in restorative dentistry are introduced at a fast pace with limited knowledge about their properties. Comparing properties of these materials from different restorative categories is lacking but can help the clinician in material selection. This study aimed to compare mechanical properties and wear resistance of bis-acryl-, composite-, and ceramic-resin restorative materials. METHODS AND MATERIALS Bisacryl-resin (Bis-R, LuxaCrown, DMG), composite-resin (Com-R, Filtek Supreme Ultra, 3M Oral Care), and ceramic-resin (Cer-R, Enamic, VITA Zahnfabrik) specimens were prepared for mechanical tests: fracture toughness (FT) with and without initial thermomechanical loading using a mastication simulator, flexural strength (FS), and flexural modulus (FM), compressive strength (CS), and volumetric wear loss measurement. The datasets for FT and wear resistance were each analyzed using two-way ANOVA followed by pairwise comparisons or Tukey testing as appropriate. The datasets for FS, FM, and CS were analyzed using one-way ANOVA followed by the Tukey test. RESULTS Analysis of FS, FM, and CS showed significant differences between materials, with all pairwise comparisons between materials showing significance. Analysis of FT resulted in a significant interaction between the material and treatment, with analysis of wear loss showing a significant interaction between the material and the number of cycles. CONCLUSIONS Cer-R demonstrated superior FT, CS, and wear resistance compared to Bis-R and Comp-R materials. Fracture toughness of Bis-R increased after thermomechanical loading.
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Affiliation(s)
- T A Sulaiman
- *Taiseer A Sulaiman, DDS, PhD, assistant professor, Division of Comprehensive Oral Health, University of North Carolina, Adams School of Dentistry, Chapel Hill, NC, USA
| | - A A Suliman
- Abdulhaq Suliman, BDS, MS, MS, PhD, professor, Restorative Dentistry Department, College of Dentistry, Ajman University, Ajman, UAE
| | - E A Mohamed
- Esraa A Mohamed, BSc (Eng.), research assistant, Oral and Craniofacial Health Sciences, University of North Carolina, Adams School of Dentistry, Chapel Hill, NC, USA
| | - B Rodgers
- Brandon Rodgers, BS, research assistant, Oral and Craniofacial Health Sciences, University of North Carolina, Adams School of Dentistry, Chapel Hill, NC, USA
| | - A Altak
- Ali Altak, DDS, resident, Graduate Operative and Biomaterials, Division of Comprehensive Oral Health, University of North Carolina, Adams School of Dentistry, Chapel Hill, NC, USA
| | - W M Johnston
- William M. Johnston, PhD, professor emeritus, College of Dentistry, The Ohio State University, Columbus, OH, USA
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Retinal damage related to high-intensity light-emitting diode exposure: An in vivo study. Am J Orthod Dentofacial Orthop 2021; 161:e353-e360. [PMID: 34955363 DOI: 10.1016/j.ajodo.2021.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 01/01/2021] [Accepted: 01/01/2021] [Indexed: 11/21/2022]
Abstract
INTRODUCTION The objective of this investigation was to evaluate the effects of high-intensity light-emitting diode (LED) light from a curing device on the retinas of Wistar rats. METHODS Six male Wistar rats were used, and their ocular structures were the focus of this study. During the photostimulation of each animal, the right eye of the animal, considered the control sample, was covered with a removable polyvinyl chloride cap, and the contralateral eye, the experimental sample, was exposed to high-intensity LED light, 3200 mW/cm2 (VALO Ortho; Ultradent Products, South Jordan, Utah) for 144 seconds from a distance of 30 cm. The animals were exposed to the LED light 3 times on the same day to investigate if any acute inflammatory changes in the retina occurred. Seven days after the photostimulation sessions, the animals were anesthetized and perfused with paraformaldehyde solution. After which, the eyes were resected and processed histologically. The histologic sections were analyzed stereologically and histomorphometrically to measure the parameters of the retina under investigation. RESULTS There was a statistically significant increase in total retinal volume in the experimental group because of the increased volume of the ganglion cell layers, inner plexiform layers, outer nuclear layers, and the cone and rod extensions. There was no statistically significant difference in terms of density. However, there was a statistically significant increase in the nuclear area of the cells in all the studied layers in the group exposed to high-intensity LED light. In addition, hyperchromatic cells that are suggestive of pyknosis were observed. CONCLUSIONS An acute but short protocol of exposure of high-intensity LED light to the eye caused morphometric alterations in the retinal structures, specifically in the nuclear area of the photosensitive cells.
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Pyszka I, Jędrzejewska B. Acenaphthoquinoxaline Derivatives as Dental Photoinitiators of Acrylates Polymerization. MATERIALS (BASEL, SWITZERLAND) 2021; 14:4881. [PMID: 34500971 PMCID: PMC8432685 DOI: 10.3390/ma14174881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/22/2021] [Accepted: 08/25/2021] [Indexed: 11/24/2022]
Abstract
A series of dyes based on the acenaphthoquinoxaline skeleton was synthesized. Their structure was modified by introducing electron-withdrawing and electron-donating groups, increasing the number of conjugated double bonds and the number and position of nitrogen atoms, as well as the arrangement of aromatic rings (linear or angular). The dyes were investigated as a component in the photoinitiating systems of radical polymerization for a potential application in dentistry. They acted as the primary absorber of visible light and the acceptor of an electron, which was generated from a second component being an electron donor. Thus, the radicals were generated by the photoinduced intermolecular electron transfer (PET) process. Electron donors used differed in the type of heteroatom, i.e., O, S and N and the number and position of methoxy substituents. To test the ability to initiate the polymerization reaction by photoinduced hydrogen atom transfer, we used 2-mercaptobenzoxazole as a co-initiator. The effectiveness of the photoinitiating systems clearly depends on both the modified acenaphthoquinocaline structure and the type of co-initiator. The lower amount of heat released during the chain reaction and the polymerization rate comparable to this achieved for the photoinitiator traditionally used in dentistry (camphorquinone) indicates that the studied dyes may be valuable in this field.
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Affiliation(s)
- Ilona Pyszka
- Faculty of Chemical Technology and Engineering, UTP University of Science and Technology, Seminaryjna 3, 85-326 Bydgoszcz, Poland
| | - Beata Jędrzejewska
- Faculty of Chemical Technology and Engineering, UTP University of Science and Technology, Seminaryjna 3, 85-326 Bydgoszcz, Poland
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Klein-Junior CA, Sobieray K, Zimmer R, Portella FF, Reston EG, Marinowic D, Hosaka K. Effect of heat treatment on cytotoxicity and polymerization of universal adhesives. Dent Mater J 2020; 39:970-975. [PMID: 32611987 DOI: 10.4012/dmj.2019-103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To assess, in vitro, the influence of heat air treatment on cytotoxicity and degree of conversion (DC) of universal self-etch adhesives (Ambar Universal APS, Scotchbond Universal Adhesive, and Tetric N-Bond Universal) in an NIH/3T3 fibroblast cell culture. Samples were divided into three groups: 1) no heat treatment (control), 2) 37°C and 3) 60°C heat treatment before photopolymerization. Cytotoxicity was analyzed by MTT assay and the DC by FTIR. All adhesives heated at 60°C showed reduced cytotoxicity levels when compared with those heated at 37°C. In general, DC of Ambar Universal APS presented the highest DC than Scotchbond Universal Adhesive and Tetric N-Bond Universal, and the hot air treatment do not influence the conversion. Heat treatment at 60°C was able to reduce the cytotoxicity of universal self-etch adhesives, even, the heat treatment does not enhances the DC.
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Affiliation(s)
| | - Kathleen Sobieray
- Department of Operative Dentistry, School of Dentistry, Universidade Luterana do Brasil (ULBRA)
| | - Roberto Zimmer
- Department of Operative Dentistry, School of Dentistry, Universidade Luterana do Brasil (ULBRA)
| | | | - Eduardo Galia Reston
- Department of Operative Dentistry, School of Dentistry, Universidade Luterana do Brasil (ULBRA)
| | - Daniel Marinowic
- Brain Institute, Neuroscience laboratory, Pontificia Universidade Católica do Rio Grande do Sul (PUC)
| | - Keiichi Hosaka
- Department of Oral Health Science, School of Medical and Dental Science, Tokyo Medical and Dental University
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Balhaddad AA, Garcia I, Collares F, Felix CM, Ganesh N, Alkabashi Q, Massei W, Strassler H, Melo MA. Assessment of the radiant emittance of damaged/contaminated dental light-curing tips by spectrophotometric methods. Restor Dent Endod 2020; 45:e55. [PMID: 33294420 PMCID: PMC7691262 DOI: 10.5395/rde.2020.45.e55] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/09/2020] [Accepted: 06/09/2020] [Indexed: 12/03/2022] Open
Abstract
Objectives This study investigated the effects of physically damaged and resin-contaminated tips on radiant emittance, comparing them with new undamaged, non-contaminated tips using 3 pieces of spectrophotometric laboratory equipment. Materials and Methods Nine tips with damage and/or resin contaminants from actual clinical situations were compared with a new tip without damage or contamination (control group). The radiant emittance was recorded using 3 spectrophotometric methods: a laboratory-grade thermopile, a laboratory-grade integrating sphere, and a portable light collector (checkMARC). Results A significant difference between the laboratory-grade thermopile and the laboratory-grade integrating sphere was found when the radiant emittance values of the control or damaged/contaminated tips were investigated (p < 0.05), but both methods were comparable to checkMARC (p > 0.05). Regardless of the method used to quantify the light output, the mean radiant emittance values of the damaged/contaminated tips were significantly lower than those of the control (p < 0.05). The beam profile of the damaged/contaminated tips was less homogeneous than that of the control. Conclusions Damaged/contaminated tips can reduce the radiant emittance output and the homogeneity of the beam, which may affect the energy delivered to composite restorations. The checkMARC spectrophotometer device can be used in dental offices, as it provided values close to those produced by a laboratory-grade integrated sphere spectrophotometer. Dentists should assess the radiant emittance of their light-curing units to ensure optimal curing in photoactivated, resin-based materials.
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Affiliation(s)
- Abdulrahman A Balhaddad
- Dental Biomedical Sciences PhD Program, University of Maryland School of Dentistry, Baltimore, MD, USA.,Department of Restorative Dental Sciences, Imam Abdulrahman Bin Faisal University, College of Dentistry, Dammam, Saudi Arabia
| | - Isadora Garcia
- Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fabrício Collares
- Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Cristopher M Felix
- BlueLight Analytics Company, Halifax, NS, Canada.,Department of Dental Clinical Sciences, Dalhousie University, Halifax, NS, Canada
| | - Nisha Ganesh
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Qoot Alkabashi
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Ward Massei
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Howard Strassler
- Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
| | - Mary Anne Melo
- Dental Biomedical Sciences PhD Program, University of Maryland School of Dentistry, Baltimore, MD, USA.,Division of Operative Dentistry, Department of General Dentistry, University of Maryland School of Dentistry, Baltimore, MD, USA
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Tabassum S, Hameed MH, Khan FR. Comparison of the Depth of Cure of Flowable Composites Polymerized at Variable Increment Thicknesses and Voltages: An In vitro Study. Contemp Clin Dent 2020; 10:220-225. [PMID: 32308281 PMCID: PMC7145244 DOI: 10.4103/ccd.ccd_635_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Objectives The aim of this study is to compare the depth of cure of two composite materials (SDR and Filtek bulk-fill) cured at variable increment depths (2, 4, and 6 mm) and voltages (180 and 220 volts). Materials and Methods Each sample of the composite material was packed in a mold of 2 mm, 4 mm, and 6 mm and curing light (quartz tungsten halogen) of optimal intensity was exposed for 20 s at 2 different voltages on each specimen. After curing, the specimens were removed and the composite on the nonexposed end was scraped with a plastic instrument. The remaining composite thickness was measured using a digital Vernier caliper. The reading was divided by half to follow the ISO 4049 method. Independent sample t-test, one-way ANOVA, and linear regression analysis were applied. Level of significance was kept at 0.01. Results The mean DOC of SDR and Filtek were 1.93 ± 0.82 and 1.77 ± 0.65 mm. Lowering the voltage from 220 to 180 volts reduced the depth of Filtek from 1.87 ± 0.74 to 1.67 ± 0.54 mm, whereas the DOC of SDR remained unchanged at 1.93 mm at the two voltages. The adjusted R 2 for the depth of cure was 0.93 when the increment thickness, voltage, and restorative material were taken together in the regression model. Conclusions There was no statistically significant difference between SDR and Filtek for the depth of cure at 2 and 4 mm increments. However, at 6 mm increment, the SDR cured significantly deeper than the Filtek. Around 91% variation in the depth of cure of these composites materials is explained by increment thickness alone.
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Affiliation(s)
- Sadia Tabassum
- Department of Operative Dentistry, Jinnah Medical and Dental College, Karachi, Pakistan
| | | | - Farhan Raza Khan
- Department of Operative Dentistry, Aga Khan University Hospital, Karachi, Pakistan
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Tanthanuch S, Kukiattrakoon B. The effect of curing time by conventional quartz tungsten halogens and new light-emitting diodes light curing units on degree of conversion and microhardness of a nanohybrid resin composite. J Conserv Dent 2019; 22:196-200. [PMID: 31142993 PMCID: PMC6519180 DOI: 10.4103/jcd.jcd_498_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background: Little is known about the relationship between the minimal light-curing time required for proper polymerization on various quartz–tungsten–halogen (QTH) and light-emitting diode (LED) light-curing units that have different light intensities. Aim: To evaluate the effects of curing time by QTH and LED light-curing units on the degree of conversion (DoC) and surface microhardness of a nanohybrid resin composite. Setting and Design: Experimental design. Materials and Methods: One hundred and twenty cylindrical specimens (4.0 mm in diameter, 2.0 mm thick) of shade A2 resin composite were prepared and polymerized with either QTHs or LEDs for 20 and 40 s. The DoC and the top and bottom surface microhardness were recorded. Statistical Analysis Used: Two-way analysis of variance, Tukey's test, and the t-test (α = 0.05) were used. Results: Surface microhardness and DoC values were affected by light intensity and curing time (P < 0.05). In terms of microhardness and DoC, LED groups gave significantly more values than QTH groups (P < 0.05). Conclusion: Curing time affected surface microhardness and DoC values of a nanohybrid resin composite in both conventional QTH and new LED light-curing units.
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Affiliation(s)
- Saijai Tanthanuch
- Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Boonlert Kukiattrakoon
- Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.,Dental Materials Research Unit (Second Phase), Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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Majumder A, Giri TK, Mukherjee S. An in vitro study to compare the influence of different all-ceramic systems on the polymerization of dual-cure resin cement. J Indian Prosthodont Soc 2019; 19:58-65. [PMID: 30745755 PMCID: PMC6340077 DOI: 10.4103/jips.jips_262_18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 11/21/2018] [Indexed: 11/23/2022] Open
Abstract
Aim: The aim of the study is to compare the effect of composition of three different all-ceramic systems on the polymerization of dual-cure resin cement, using different curing cycles and evaluated immediately within 15 min and after 24 h. Materials and Methods: Resin cement disc samples were fabricated by polymerization through three different all-ceramic disc, namely: lithium disilicate discs – IPS e.max (Group B), leucitereinforced discs – IPS Empress (Group C), zirconia discs – Cercon (Group D), and without an intervening ceramic disc, as control (Group A). A total of 80 resin cement disc samples were fabricated for fur groups (n = 20). Each group further consisted of two subgroups (n = 10), t10 and t20 according to two different exposure times of 10 and 20 s, respectively. Each of the 80 resin disc samples was evaluated for their degree of polymerization achieved, by measuring the microhardness(Vickers hardness number) of the samples immediately within 15 min and after 24 h, giving us a total of 160 readings. Oneway analysis of variance test, ttest, and paired ttest were used for multiple group comparisons followed by Tukey's post hoc for groupwise comparison. Results: Direct activation of the resin cement samples of control (Group A) showed statistically significant higher mean microhardness values followed by Groups C then B and D, both immediately and after 24 h. The mean microhardness for immediate post-activation was always inferior to the 24 h post-activation test. For both 10 and 20 s curing cycle, there was a significant increase in the microhardness of the resin cement discs cured for 20 s through the different ceramics. Conclusion: Ceramic composition affected the polymerization of dual cured resin cement. Doubling the light irradiation time or curing cycle significantly increased mean microhardness value. Greater degree of conversion leading to an increase in hardness was observed when the resin cement discs were evaluated after 24 h.
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Affiliation(s)
- Anindita Majumder
- Department of Prosthodontics Crown and Bridge, Dr. R Ahmed Dental College and Hospital, Kolkata, West Bengal, India
| | - T K Giri
- Department of Prosthodontics Crown and Bridge, Dr. R Ahmed Dental College and Hospital, Kolkata, West Bengal, India
| | - S Mukherjee
- Department of Prosthodontics Crown and Bridge, Dr. R Ahmed Dental College and Hospital, Kolkata, West Bengal, India
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Alquria T, Al Gady M, Khabeer A, Ali S. Types of polymerisation units and their intensity output in private dental clinics of twin cities in eastern province, KSA; a pilot study. J Taibah Univ Med Sci 2019; 14:47-51. [PMID: 31435389 PMCID: PMC6694879 DOI: 10.1016/j.jtumed.2018.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/10/2018] [Accepted: 11/12/2018] [Indexed: 11/24/2022] Open
Abstract
Objectives Light-cured resin-based composites (RBCs) are the preferred option to restore teeth. Dental light-curing units (LCUs) should deliver adequate light energy to ensure good mechanical properties, dimensional stability, and biocompatibility of the RBC. The aim of this study was to determine the types of LCUs and their intensity output in private dental clinics. Methods A form was developed to record information related to the type of curing lights and their intensity output. A total of 400 curing devices were evaluated using a digital radiometer in 58 private dental clinics. For each device, three separate 10-s readings were taken and the average was calculated. For quartz tungsten halogen (QTH) units, a light intensity below 300 mW/cm2 was considered unsatisfactory, whereas for light-emitting diode (LED) units, a reading below 600 mW/cm2 was considered unsatisfactory. Results Out of 400 curing lights, 354 were LEDs and 46 were QTH units. A total of 13% of the lights were considered unsatisfactory. Of the LED units, 12.4% had a light intensity of less than 600 mW/cm2, whereas QTH had 17.3% units with an intensity of less than 300 mW/cm2. Conclusion The frequency of LCUs showed a trend towards LED units in private dental clinics, whereas the mean intensity value from the LED was higher than that from QTH units. Overall, the radiometer is a good tool to assess the intensity output of LCUs.
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Guram G, Shaik JA. Comparison of Light-Emitting Diode-Curing Unit and Halogen-Based Light-Curing Unit for the Polymerization of Orthodontic Resins: An In vitro Study. J Int Soc Prev Community Dent 2018; 8:409-415. [PMID: 30430067 PMCID: PMC6187877 DOI: 10.4103/jispcd.jispcd_302_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 09/22/2017] [Indexed: 11/04/2022] Open
Abstract
Aims and Objectives Conventionally, composites are cured using halogen-based light-curing units (LCUs). However, recently, light-emitting diode (LED) LCUs have been introduced commercially, claiming many advantages, yet producing comparable bond strength even when cured with single LED LCUs. This present study was undertaken to compare the shear bond strength of orthodontic brackets bonded to teeth with conventional halogen LCU (3M ESPE Elipar 2500) and LED LCU (3M ESPE Elipar FreeLight 2) and to determine the site of bond failure. Materials and Methods Fifty extracted human bicuspid teeth were randomly divided into two groups of 25 each. All the teeth were etched and primed. Then, orthodontic brackets were bonded onto the teeth with the light-cured adhesive (Transbond XT, 3M Unitek), and the adhesive was cured with halogen LCU and LED LCU for Group I and Group II, respectively. The brackets were then subjected to shear stress using a Hounsfield universal testing machine at a crosshead speed of 1 mm/min. The force was recorded in Kgf and converted to MPa. The residual adhesive was scored based on the modified adhesive remnant index (ARI) using an optical stereomicroscope. The data were analyzed using the Student's t-test and the Mann-Whitney test at a significance level of 0.05. Results The results have shown that there is no significant difference between the shear bond strengths and the ARI scores of both the groups. Conclusion From this study, it can be concluded that (1) LED LCUs containing even only a single LED can cure the composite as well as a halogen-based LCU; (2) there is no statistically significant difference in the shear bond strengths of the two groups; and (3) the ARI scores show no significant difference.
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Affiliation(s)
- Guneet Guram
- Department of Orthodontics, Adesh Institute of Dental Sciences, Bathinda, Punjab, India
| | - Junaid Ahmed Shaik
- Department of Orthodontics, Adesh Institute of Dental Sciences, Bathinda, Punjab, India
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Drost T, Reimann S, Frentzen M, Meister J. Effectiveness of photopolymerization in composite resins using a novel 445-nm diode laser in comparison to LED and halogen bulb technology. Lasers Med Sci 2018; 34:729-736. [PMID: 30291465 DOI: 10.1007/s10103-018-2651-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 09/27/2018] [Indexed: 11/25/2022]
Abstract
Challenges especially in the minimal invasive restorative treatment of teeth require further developments of composite polymerization techniques. These include, among others, the securing of a complete polymerization with moderate thermal stress for the pulp. The aim of this study is to compare current light curing sources with a blue diode laser regarding curing depth and heat generation during the polymerization process. A diode laser (445 nm), a LED, and a halogen lamp were used for polymerizing composite resins. The curing depth was determined according to the norm ISO 4049. Laser output powers of 0.1, 0.5, 1, and 2 W were chosen. The laser beam diameter was adapted to the glass rod of the LED and the halogen lamp (8 mm). The irradiation time was fixed at 40 s. To ascertain ΔT values, the surface and ground area temperatures of the cavities were simultaneously determined during the curing via a thermography camera and a thermocouple. The curing depths for the LED (3.3 mm), halogen lamp (3.1 mm) and laser(0.5/1 W) (3/3.3 mm) showed no significant differences (p < 0.05). The values of ΔTsurface as well as ΔTground also showed no significant differences among LED, halogen lamp, and laser(1 W). The ΔTsurface values were 4.1LED, 4.3halogen lamp, and 4.5 °C for the laser while the ΔTground values were 2.7LED, 2.6halogen lamp, and 2.9 °C for the laser. The results indicate that the blue diode laser (445 nm) is a feasible alternative for photopolymerization of complex composite resin restorations in dentistry by the use of selected laser parameters.
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Affiliation(s)
- Thomas Drost
- Department of Operative and Preventive Dentistry, Bonn University, Dental Faculty, Welschnonnenstrasse 17, 53111, Bonn, Germany
| | - Susanne Reimann
- Oral Technology, Bonn University, Dental Faculty, 53111, Bonn, Germany
| | - Matthias Frentzen
- Department of Operative and Preventive Dentistry, Bonn University, Dental Faculty, Welschnonnenstrasse 17, 53111, Bonn, Germany
| | - Jörg Meister
- Department of Operative and Preventive Dentistry, Bonn University, Dental Faculty, Welschnonnenstrasse 17, 53111, Bonn, Germany.
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16
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Pflaum T, Kranz S, Montag R, Güntsch A, Völpel A, Mills R, Jandt K, Sigusch B. Clinical long-term success of contemporary nano-filled resin composites in class I and II restorations cured by LED or halogen light. Clin Oral Investig 2017; 22:1651-1662. [PMID: 29080928 DOI: 10.1007/s00784-017-2226-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/27/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The use of LED light-curing units (LED LCUs) for polymerising resin-based composite restorations has become widespread throughout dentistry. Unfortunately, there is a paucity of clinical longitudinal studies that evaluate the comparative efficacy of LED-based polymerisation in direct posterior composite restorations. The aim of the present study was to investigate the performance of class I and II resin composite restorations for two successful composite restorative materials cured with LED versus halogen LCUs. METHODS One hundred restorations were placed using the nano-filled composites Grandio® or Filtek™ Supremé. The following test groups were established: LED-Grandio® n = 23 (LG), LED-Filtek™ Supremé n = 21 (LS). As controls were used: Halogen-Grandio® n = 28 (HG), Halogen-Filtek™ Supremé n = 28 (HS). All restorations were evaluated according to the clinical criteria of the CPM index (C-criteria) at baseline and after 6, 12 and 36 months. RESULTS After 12 and 36 months, there were no significant differences between restorations polymerised with LED or halogen light. At the end of the study, 97% of the restorations showed sufficient results regardless of the employed LCU or composite. Globally, after 36 months, 56% of all restorations were assessed with code 0 (excellent) and 41% with code 1 (acceptable). In detail, excellent results (code 0) among the criteria surface quality; marginal integrity and marginal discoloration were assigned in 72, 70 and 69%. CONCLUSIONS For the current limitations in the clinical trial design, the results showed that LED-polymerisation is appropriate to ensure clinical success of direct posterior resin composite restorations in a range of 3 years. CLINICAL SIGNIFICANCE The choice of LCU has no significant influence on the clinical performance of posterior direct resin composite restorations within 3 years of wear.
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Affiliation(s)
- Torsten Pflaum
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany.
| | - Stefan Kranz
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany
| | - Regina Montag
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany
| | - Arndt Güntsch
- Department of Surgical Sciences, Marquette University, Milwaukee, USA
| | - Andrea Völpel
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany
| | - Robin Mills
- School of Oral and Dental Sciences, University of Bristol, Bristol, BS1 2LY, UK
| | - Klaus Jandt
- Otto Schott Institute for Materials Research, 07743, Jena, Germany
| | - Bernd Sigusch
- Policlinic of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743, Jena, Germany
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Conte G, Panetta M, Mancini M, Fabianelli A, Brotzu A, Sorge R, Cianconi L. Curing effectiveness of single-peak and multi-peak led light curing units on tpo-containing resin composites with different chromatic characteristics. ACTA ACUST UNITED AC 2017; 10:140-150. [PMID: 29876039 DOI: 10.11138/orl/2017.10.2.140] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study evaluated the surface microhardness of Lucirin-TPO (TPO) containing resin based composite (RBC) cured with three light-emitting diode (LED) light curing units (LCUs) (two single-peak LED and one multi-peak LED), and two different energy density (ED) (8 J/cm2 and 16 J/cm2). Ninety specimens (8 mm wide and 2 mm thick) (n=5), were prepared with three different shades: translucent (T), A2 dentin (A2d), and A4 dentin (A4d). Specimens were subjected to micro-hardness Vickers measurements (Vickers Hardness Number, VHN) on both top and bottom surfaces. Hardness ratio (rHV) was also calculated. Data were analyzed using multifactorial ANOVA and Bonferroni tests (<=0.05). Results indicated that higher ED performed better than lower ED. Multi-peak LED achieved higher VHNs and rHV than single-peak LED when curing a TPO-containing RBC. A4d invariably achieved lower rHV and VHN than T and A2d. Single-peak LED achieved comparable VHNs and rHVs with multi-peak LED only curing A2d and T shades with 16J/cm2.
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Affiliation(s)
- G Conte
- Department of Restorative Dentistry, Endodontics and Biomaterials, University of Rome "Tor Vergata", Rome, Italy
| | - M Panetta
- Department of Restorative Dentistry, Endodontics and Biomaterials, University of Rome "Tor Vergata", Rome, Italy
| | - M Mancini
- Department of Restorative Dentistry, Endodontics and Biomaterials, University of Rome "Tor Vergata", Rome, Italy
| | - A Fabianelli
- Visiting lecturer in Sheffield University, Sheffield, UK
| | - A Brotzu
- Department of ICMA, "Sapienza" University of Rome, Rome, Italy
| | - R Sorge
- Department of Human Physiology, Laboratory of Biometry, University of Rome "Tor Vergata", Rome, Italy
| | - L Cianconi
- Department of Restorative Dentistry, Endodontics and Biomaterials, University of Rome "Tor Vergata", Rome, Italy
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Lima AF, Formaggio SEF, Zambelli LFA, Palialol ARM, Marchi GM, Saraceni CHC, de Oliveira MT. Effects of radiant exposure and wavelength spectrum of light-curing units on chemical and physical properties of resin cements. Restor Dent Endod 2016; 41:271-277. [PMID: 27847748 PMCID: PMC5107428 DOI: 10.5395/rde.2016.41.4.271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/05/2016] [Indexed: 11/24/2022] Open
Abstract
Objectives In this study, we evaluated the influence of different radiant exposures provided by single-peak and polywave light-curing units (LCUs) on the degree of conversion (DC) and the mechanical properties of resin cements. Materials and Methods Six experimental groups were established for each cement (RelyX ARC, 3M ESPE; LuxaCore Dual, Ivoclar Vivadent; Variolink, DMG), according to the different radiant exposures (5, 10, and 20 J/cm2) and two LCUs (single-peak and polywave). The specimens were made (7 mm in length × 2 mm in width × 1 mm in height) using silicone molds. After 24 hours of preparation, DC measurement was performed using Fourier transform infrared spectrometry. The same specimens were used for the evaluation of mechanical properties (flexural strength, FS; elastic modulus, E) by a three-point bending test. Data were assessed for normality, after which two-way analysis of variance (ANOVA) and post hoc Tukey's test were performed. Results No properties of the Variolink cement were influenced by any of the considered experimental conditions. In the case of the RelyX ARC cement, DC was higher when polywave LCU was used; FS and E were not influenced by the conditions evaluated. The LuxaCore cement showed greater sensitivity to the different protocols. Conclusions On the basis of these results, both the spectrum of light emitted and the radiant exposure used could affect the properties of resin cements. However, the influence was material-dependent.
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Affiliation(s)
- Adriano Fonseca Lima
- Dental Research Division, School of Dentistry, Paulista University, Sao Paulo, SP, Brazil
| | | | | | - Alan Rodrigo Muniz Palialol
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
| | - Giselle Maria Marchi
- Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
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Pahlevan A, Tabatabaei MH, Arami S, Valizadeh S. Effect of LED and Argon Laser on Degree of Conversion and Temperature Rise of Hybrid and Low Shrinkage Composite Resins. Open Dent J 2016; 10:538-545. [PMID: 27843507 PMCID: PMC5074004 DOI: 10.2174/1874210601610010538] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 07/11/2016] [Accepted: 08/07/2016] [Indexed: 11/22/2022] Open
Abstract
Objectives: Different light curing units are used for polymerization of composite resins. The aim of this study was to evaluate the degree of conversion (DC) and temperature rise in hybrid and low shrinkage composite resins cured by LED and Argon Laser curing lights. Materials and Methods: DC was measured using FTIR spectroscopy. For measuring temperature rise, composite resin samples were placed in Teflon molds and cured from the top. The thermocouple under samples recorded the temperature rise. After initial radiation and specimens reaching the ambient temperature, reirradiation was done and temperature was recorded again. Both temperature rise and DC data submitted to one-way ANOVA and Tukey-HSD tests (5% significance). Results: The obtained results revealed that DC was not significantly different between the understudy composite resins or curing units. Low shrinkage composite resin showed a significantly higher temperature rise than hybrid composite resin. Argon laser caused the lowest temperature rise among the curing units. Conclusion: Energy density of light curing units was correlated with the DC. Type of composite resin and light curing unit had a significant effect on temperature rise due to polymerization and curing unit, respectively.
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Affiliation(s)
- Ayob Pahlevan
- Operative Dentist, Tehran University of Medical Science, North Amir-Abad, Tehran, Iran
| | | | - Sakineh Arami
- Operative Dentist, Tehran University of Medical Science, North Amir-Abad, Tehran, Iran
| | - Sara Valizadeh
- Operative Dentist, Tehran University of Medical Science, North Amir-Abad, Tehran, Iran
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Bani M, Tirali RE. Effect of new light curing units on microleakage and microhardness of resin sealants. Dent Mater J 2016; 35:517-22. [PMID: 27252010 DOI: 10.4012/dmj.2015-357] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To determine new developed light curing units with shorter curing times effects on microleakage and microhardness values for resin fissure sealants. Resin filled sealant (UltraSeal-XT), resin unfilled sealant (Delton Type-II) and ormocer-based sealant (Admira-Seal) were light cured with a quartz-tungsten-halogen (QTH), two LED light and a high power LED. Two hundred and forty extracted human molars were randomly allocated into four groups according to used light-curing unit and three subgroups were formed for three different fissure sealant materials. Specimens were immersed in 0.5% basic fuchsin for 24 h, sectioned and examined under a stereomicroscope, and scored for marginal microleakage. Knoop hardness number (KHN) readings were measured after 48 h. Statistical analyses of test were found in significant difference both microleakage and microhardness values between the various light curing units. The time saving approaches in the curing light were determined higher microhardness, although it was found in higher microleakage.
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Affiliation(s)
- Mehmet Bani
- Department of Pediatric Dentistry, Faculty of Dentistry, Gazi University
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Gultekin P, Pak Tunc E, Ongul D, Turp V, Bultan O, Karataslı B. Curing efficiency of dual-cure resin cement under zirconia with two different light curing units. J Istanb Univ Fac Dent 2015; 49:8-16. [PMID: 28955530 PMCID: PMC5573479 DOI: 10.17096/jiufd.97059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/09/2015] [Indexed: 11/19/2022] Open
Abstract
Purpose: Adequate polymerization is a crucial factor in obtaining optimal physical properties and a satisfying
clinical performance from composite resin materials. The aim of this study was to evaluate the polymerization efficiency of
dual-cure resin cement cured with two different light curing units under zirconia structures having differing thicknesses. Materials and Methods: 4 zirconia discs framework in 4 mm diameter and in 0.5 mm, 1 mm and 1.5 mm thickness
were prepared using computer-aided design system. One of the 0.5 mm-thick substructures was left as mono-layered
whereas others were layered with feldspathic porcelain of same thickness and ceramic samples with 4 different
thicknesses (0.5, 1, 1.5 and 2.0 mm) were prepared. For each group (n=12) resin cement was light cured in
polytetrafluoroethylene molds using Light Emitting Diode (LED) or Quartz-Tungsten Halogen (QHT) light curing
units under each of 4 zirconia based discs (n=96). The values of depth of cure (in mm) and the Vickers Hardness
Number values (VHN) were evaluated for each specimen. Results: The use of LED curing unit produced a greater depth of cure compared to QTH under ceramic discs
with 0.5 and 1 mm thickness (p<0.05).At 100μm and 300 μm depth, the LED unit produced significantly greater
VHN values compared to the QTH unit (p<0.05). At 500 μm depth, the difference between the VHN values of
LED and QTH groups were not statistically significant. Conclusion: Light curing may not result in adequate resin cement polymerization under thick zirconia structures.
LED light sources should be preferred over QTH for curing dual-cure resin cements, especially for those under thicker zirconia restorations.
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Affiliation(s)
- Pınar Gultekin
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Turkey
| | - Elif Pak Tunc
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Turkey
| | - Deger Ongul
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Turkey
| | - Volkan Turp
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Turkey
| | - Ozgur Bultan
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Turkey
| | - Burcin Karataslı
- Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Turkey
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Kitchens B, Wells M, Tantbirojn D, Versluis A. Depth of cure of sealants polymerized with high-power light emitting diode curing lights. Int J Paediatr Dent 2015; 25:79-86. [PMID: 24628863 DOI: 10.1111/ipd.12102] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To determine whether recommended short curing times of three high-power light emitting diode (LED) curing lights are sufficient to polymerize sealant materials. METHODS Opaque-unfilled sealant (Delton LC Opaque), opaque-filled sealant (UltraSeal XT plus), and clear-filled sealant (FluroShield) were light cured in a covered slot-mold using the manufacturers' shortest recommended curing times with three high-power LED lights (3-s VALO, 5-s Fusion, 10-s Smartlite). A 40-s cure with a quartz-tungsten halogen (QTH) light was used as control. Vickers hardness was measured 24 h after curing at the sealant surface and through the depth (0.5 mm increments) (N = 10). Results were analyzed with two-way anova (pair-wise multiple comparisons, significance level 0.05). RESULTS The high-power LEDs did not cure the sealants as deep as the QTH. Delton LC Opaque showed the least depth of cure as hardness values beyond a depth of 0.5 mm were not measurable regardless of the curing light. Even for UltraSeal XT plus, when surface hardness was about the same with all lights, hardness decreased more rapidly with depth for the LEDs. FluroShield showed the slowest decline in hardness through the depth for all lights. CONCLUSIONS Manufacturers' recommendations for shortest possible curing time with high-power LEDs were not sufficient for adequate polymerization of the tested sealants.
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Affiliation(s)
- Brandon Kitchens
- Department of Pediatric Dentistry, College of Dentistry, University of Tennessee Health Science Center, Memphis, TN, USA
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KARAMAN E, GÖNÜLOL N. Does the light source affect the repairability of composite resins? Braz Oral Res 2014; 28:S1806-83242014000100238. [DOI: 10.1590/1807-3107bor-2014.vol28.0027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 03/13/2014] [Indexed: 11/22/2022] Open
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Shiomuki D, Minami H, Tanaka T, Suzuki S. Influence of light irradiation on Vickers hardness of dual-cure cement polymerized under restorations. Dent Mater J 2014; 32:449-55. [PMID: 23719007 DOI: 10.4012/dmj.2012-306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study evaluated, by measuring Vickers hardness (Hv), the effects of these factors on the degree of polymerization of dual-cure cement (Panavia F2.0) placed under a restoration: light transmission property of restoratives materials, distance from the directly irradiated surface, and elapsed time after light irradiation. Two materials were used for the restoration: silver-palladium-copper-gold alloy (Alloy) versus zirconia (ZR). Restorations were cemented on bovine enamel by dual-cure cement. At 30 min, 2 h, 6 h, 1 day, and 1 week after definitive irradiation, Hv values at the enamel side of cement were evaluated at three measuring points: two points at the left and right margins and one point at the center. Data were analyzed by two-way ANOVA with Bonferroni correction (α=0.05). With the Alloy restoration, Hv value at the center was significantly lower than those at the margins at 30 min after irradiation. For both Alloy and ZR restorations, Hv value at each measuring point continued to increase significantly up to 6 h.
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Affiliation(s)
- Daisaku Shiomuki
- Fixed Prosthetic Clinic, Kagoshima University Medical and Dental Hospital, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
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Karakis D, Yildirim-Bicer AZ, Erol O, Dogan A. Effects of different polymerization protocols on the degree of conversion of two dual-cured core buildup composites polymerized by light-emitting diode and halogen light-curing units. J Appl Polym Sci 2014. [DOI: 10.1002/app.40560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Duygu Karakis
- Department of Prosthodontics; Faculty of Dentistry; University of Gazi; Ankara Turkey
| | | | - Ozlem Erol
- Department of Chemistry; Faculty of Science; University of Gazi; Ankara Turkey
| | - Arife Dogan
- Department of Prosthodontics; Faculty of Dentistry; University of Gazi; Ankara Turkey
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Nazir R, Danilevicius P, Gray D, Farsari M, Gryko DT. Push–Pull Acylo-Phosphine Oxides for Two-Photon-Induced Polymerization. Macromolecules 2013. [DOI: 10.1021/ma4010988] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rashid Nazir
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Paulius Danilevicius
- Institute
of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH), P.O. Box 1527, 711 10 Heraklion, Crete, Greece
| | - David Gray
- Institute
of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH), P.O. Box 1527, 711 10 Heraklion, Crete, Greece
| | - Maria Farsari
- Institute
of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH), P.O. Box 1527, 711 10 Heraklion, Crete, Greece
| | - Daniel T. Gryko
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
- Institute
of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw, Poland
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Orçun Zorba Y, Bayındır YZ, Turgut H, Yıldız M. Quality of curing in relation to different light sources by measuring hardness, degree of conversion and depth of cure. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/143289109x12494867167521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- Y. Orçun Zorba
- Department of EndodonticsDentistry Faculty, Kırıkkale University, Kırıkkale, Turkey
| | - Y. Z. Bayındır
- Department of Restorative DentistryDentistry Faculty, Atatürk University, Erzurum, Turkey
| | - H. Turgut
- Department of Restorative DentistryDentistry Faculty, Atatürk University, Erzurum, Turkey
| | - M. Yıldız
- Department of Restorative DentistryDentistry Faculty, Atatürk University, Erzurum, Turkey
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Jandt KD, Mills RW. A brief history of LED photopolymerization. Dent Mater 2013; 29:605-17. [DOI: 10.1016/j.dental.2013.02.003] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 02/12/2013] [Accepted: 02/12/2013] [Indexed: 11/26/2022]
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Gonsalvi L, Peruzzini M. Neue Synthesewege für Bisacylphosphinoxid-Photoinitiatoren. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201203648] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Gonsalvi L, Peruzzini M. Novel Synthetic Pathways for Bis(acyl)phosphine Oxide Photoinitiators. Angew Chem Int Ed Engl 2012; 51:7895-7. [DOI: 10.1002/anie.201203648] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Indexed: 12/13/2022]
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Wahbi MA, Aalam FA, Fatiny FI, Radwan SA, Eshan IY, Al-Samadani KH. Characterization of heat emission of light-curing units. Saudi Dent J 2012; 24:91-8. [PMID: 23960535 DOI: 10.1016/j.sdentj.2012.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 11/22/2011] [Accepted: 01/31/2012] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVES This study was designed to analyze the heat emissions produced by light-curing units (LCUs) of different intensities during their operation. The null hypothesis was that the tested LCUs would show no differences in their temperature rises. METHODS FIVE COMMERCIALLY AVAILABLE LCUS WERE TESTED: a "Flipo" plasma arc, "Cromalux 100" quartz-tungsten-halogen, "L.E. Demetron 1" second-generation light-emitting diode (LED), and "Blue Phase C5" and "UltraLume 5" third-generation LED LCUs. The intensity of each LCU was measured with two radiometers. The temperature rise due to illumination was registered with a type-K thermocouple, which was connected to a computer-based data acquisition system. Temperature changes were recorded in continues 10 and 20 s intervals up to 300 s. RESULTS The Flipo (ARC) light source revealed the highest mean heat emission while the L.E. Demetron 1 LED showing the lowest mean value at 10 and 20 s exposure times. Moreover, Cromalux (QTH) recorded the second highest value for all intervals (12.71, 14.63, 14.60) of heat emission than Blue Phase C5 (LED) (12.25, 13.87, 13.69), interestingly at 20 s illumination for all intervals the highest results (18.15, 19.27, 20.31) were also recorded with Flipo (PAC) LCU, and the lowest (6.71, 5.97, 5.55) with L.E. Demetron 1 LED, while Blue Phase C5 (LED) recorded the second highest value at the 1st and 2nd 20 s intervals (14.12, 11.84, 10.18) of heat emission than Cromalux (QTH) (12.26, 11.43, 10.26). The speed of temperature or heat rise during the 10 and 20 s depends on light intensity of emitted light. However, the QTH LCU was investigated resulted in a higher temperature rise than LED curing units of the same power density. CONCLUSION The PAC curing unit induced a significantly higher heat emission and temperature increase in all periods, and data were statistically different than the other tested groups (p < .05). LED (Blue Phase C5) was not statistically significant (p < .05) (at 10 s) than QTH units, also LED (Blue Phase C5, UltraLume 5) generates obvious heat emission and temperature rises than QTH units (at 20 s) except for those which have lower power density of LED curing units (first generation). Thus, the null hypothesis was rejected.
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Affiliation(s)
- Mohammed A Wahbi
- Conservative Dentistry, Makkah Dental Centre, P.O. Box 3381, Makkah, Saudi Arabia
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Gaglianone LA, Lima AF, Araújo LSND, Cavalcanti AN, Marchi GM. Influence of different shades and LED irradiance on the degree of conversion of composite resins. Braz Oral Res 2012; 26:165-9. [DOI: 10.1590/s1806-83242012005000002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Accepted: 01/04/2012] [Indexed: 11/21/2022] Open
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Gaglianone LA, Lima AF, Gonçalves LS, Cavalcanti AN, Aguiar FHB, Marchi GM. Mechanical properties and degree of conversion of etch-and-rinse and self-etch adhesive systems cured by a quartz tungsten halogen lamp and a light-emitting diode. J Mech Behav Biomed Mater 2012; 12:139-43. [PMID: 22728468 DOI: 10.1016/j.jmbbm.2012.01.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 01/18/2012] [Accepted: 01/24/2012] [Indexed: 10/28/2022]
Abstract
The aim of the present study was to evaluate the degree of conversion (DC), elastic modulus (E), and flexural strength (FS) of five adhesive systems (only the bonding component of both Scotchbond MP-SBMP and Clearfil Protect Bond-CP; Single Bond 2-SB2; One-up Bond F Plus-OUP; and P90 System Adhesive: primer-P90P and bond-P90B) cured with a quartz tungsten halogen (QTH) lamp and a light-emitting diode (LED). Two groups per adhesive were formed (n=5), according to the light source (quartz tungsten halogen-QTH: Demetron LC; and light-emitting diode-LED: UltraLume 5). Bar-shaped specimens were evaluated using three-point bending. The DC was obtained by Fourier transform infrared spectroscopy (FTIR). SB2 and P90P exhibited better DC values for QTH curing. However, SB2 and P90P presented the worst results overall. The light source was statistically significant for all adhesives, except for P90B and OUP. Non-solvated adhesives presented the best E and FS values. It could be concluded that the DC and E values can be influenced by the light source; however, this interference is material dependent.
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Affiliation(s)
- Lívia Aguilera Gaglianone
- Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Av. Limeira, 901 - Areião, 13414-903 Piracicaba, SP, Brazil.
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Leprince JG, Leveque P, Nysten B, Gallez B, Devaux J, Leloup G. New insight into the "depth of cure" of dimethacrylate-based dental composites. Dent Mater 2012; 28:512-20. [PMID: 22217607 DOI: 10.1016/j.dental.2011.12.004] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 11/29/2011] [Accepted: 12/01/2011] [Indexed: 10/14/2022]
Abstract
OBJECTIVES To demonstrate that determination of the depth of cure of resin-based composites needs to take into account the depth at which the transition between glassy and rubbery states of the resin matrix occurs. METHODS A commercially available nano-hybrid composite (Grandio) in a thick layer was light cured from one side for 10 or 40 s. Samples were analyzed by Vickers indentation, Raman spectroscopy, atomic force microscopy, electron paramagnetic imaging and differential scanning calorimetry to measure the evolution of the following properties with depth: microhardness, degree of conversion, elastic modulus of the resin matrix, trapped free radical concentration and glass transition temperature. These measurements were compared to the composite thickness remaining after scraping off the uncured, soft composite. RESULTS There was a progressive decrease in the degree of conversion and microhardness with depth as both properties still exhibited 80% of their upper surface values at 4 and 3.8 mm, respectively, for 10 s samples, and 5.6 and 4.8 mm, respectively, for 40 s samples. In contrast, there was a rapid decrease in elastic modulus at around 2.4 mm for the 10 s samples and 3.0 mm for the 40 s samples. A similar decrease was observed for concentrations of propagating radicals at 2 mm, but not for concentrations of allylic radicals, which decreased progressively. Whereas the upper composite layers presented a glass transition temperature - for 10 s, 55°C (±4) at 1 mm, 56.3°C (±2.3) at 2 mm; for 40 s, 62.3°C (±0.6) at 1 mm, 62°C (±1) at 2 mm, 62°C (±1.7) at 3 mm - the deeper layers did not display any glass transition. The thickness remaining after scraping off the soft composite was 7.01 (±0.07 mm) for 10 s samples and 9.48 (±0.22 mm) for 40 s samples. SIGNIFICANCE Appropriate methods show that the organic matrix of resin-based composite shifts from a glassy to a gel state at a certain depth. Hence, we propose a new definition for the "depth of cure" as the depth at which the resin matrix switches from a glassy to a rubbery state. Properties currently used to evaluate depth of cure (microhardness, degree of conversion or scraping methods) fail to detect this transition, which results in overestimation of the depth of cure.
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Affiliation(s)
- Julian G Leprince
- School of Dentistry and Stomatology, Université catholique de Louvain, Brussels, Belgium.
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Souza-Junior EJ, Araújo CTP, Prieto LT, Paulillo LAMS. Influence of the LED curing source and selective enamel etching on dentin bond strength of self-etch adhesives in class I composite restorations. Lasers Med Sci 2011; 27:1175-82. [PMID: 22120471 DOI: 10.1007/s10103-011-1030-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 11/07/2011] [Indexed: 11/29/2022]
Abstract
The aim of this study was to evaluate the influence of the LED curing unit and selective enamel etching on dentin microtensile bond strength (μTBS) for self-etch adhesives in class I composite restorations. On 96 human molars, box-shaped class I cavities were made maintaining enamel margins. Self-etch adhesives (Clearfil SE - CSE and Clearfil S(3) - S3) were used to bond a microhybrid composite. Before adhesive application, half of the teeth were enamel acid-etched and the other half was not. Adhesives and composites were cured with the following light curing units (LCUs): one polywave (UltraLume 5 - UL) and two single-peak (FlashLite 1401 - FL and Radii Cal - RD) LEDs. The specimens were then submitted to thermomechanical aging and longitudinally sectioned to obtain bonded sticks (0.9 mm(2)) to be tested in tension at 0.5 mm/min. The failure mode was then recorded. The μTBS data were submitted to a three-way ANOVA and Tukey's (α = 0.05). For S3, the selective enamel-etching provided lower μTBS values (20.7 ± 2.7) compared to the non-etched specimens (26.7 ± 2.2). UL yielded higher μTBS values (24.1 ± 3.2) in comparison to the photoactivation approach with FL (18.8 ±3.9) and RD (19.9 ±1.8) for CSE. The two-step CSE was not influenced by the enamel etching (p ≥ 0.05). Enamel acid etching in class I composite restorations affects the dentin μTBS of the one-step self-etch adhesive Clearfil S(3), with no alterations for Clearfil SE bond strength. The polywave LED promoted better bond strength for the two-step adhesive compared to the single-peak ones.
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Affiliation(s)
- Eduardo José Souza-Junior
- Department of Restorative Dentistry, Dental Materials Area, Piracicaba Dental School, University of Campinas, Areião, SP, Brazil.
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Ergun G, Egilmez F, Yilmaz S. Effect of reduced exposure times on the cytotoxicity of resin luting cements cured by high-power led. J Appl Oral Sci 2011; 19:286-92. [PMID: 21625748 PMCID: PMC4234344 DOI: 10.1590/s1678-77572011000300019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 04/29/2010] [Indexed: 12/03/2022] Open
Abstract
Objective Applications of resin luting agents and high-power light-emitting diodes (LED)
light-curing units (LCUs) have increased considerably over the last few years.
However, it is not clear whether the effect of reduced exposure time on
cytotoxicity of such products have adequate biocompatibility to meet clinical
success. This study aimed at assessing the effect of reduced curing time of five
resin luting cements (RLCs) polymerized by high-power LED curing unit on the
viability of a cell of L-929 fibroblast cells. Material and Methods Disc-shaped samples were prepared in polytetrafluoroethylene moulds with
cylindrical cavities. The samples were irradiated from the top through the ceramic
discs and acetate strips using LED LCU for 20 s (50% of the manufacturer's
recommended exposure time) and 40 s (100% exposure time). After curing, the
samples were transferred into a culture medium for 24 h. The eluates were obtained
and pipetted onto L-929 fibroblast cultures (3x104 per well) and
incubated for evaluating after 24 h. Measurements were performed by
dimethylthiazol diphenyltetrazolium assay. Statistical significance was determined
by two-way ANOVA and two independent samples were compared by t-test. Results Results showed that eluates of most of the materials polymerized for 20 s (except
Rely X Unicem and Illusion) reduced to a higher extent cell viability compared to
samples of the same materials polymerized for 40 s. Illusion exhibited the least
cytotoxicity for 20 s exposure time compared to the control (culture without
samples) followed by Rely X Unicem and Rely X ARC (90.81%, 88.90%, and 83.11%,
respectively). For Rely X ARC, Duolink and Lute-It 40 s exposure time was better
(t=-1.262 p=0,276; t=-9.399 p=0.001; and t=-20.418 p<0.001, respectively). Conclusion The results of this study suggest that reduction of curing time significantly
enhances the cytotoxicity of the studied resin cement materials, therefore
compromising their clinical performance.
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Affiliation(s)
- Gulfem Ergun
- Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.
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Al-kheraif AA. Effects of curing units and staining solutions on the color susceptibility of a microhybrid composite resin. J Dent Sci 2011. [DOI: 10.1016/j.jds.2011.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Marchan SM, White D, Smith WA, Raman V, Coldero L, Dhuru V. Effect of Reduced Exposure Times on the Microhardness of Nanocomposites Polymerized by QTH and Second-generation LED Curing Lights. Oper Dent 2011; 36:98-103. [DOI: 10.2341/08-093-lr2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Clinical Relevance
Reduced polymerization times suggested with newer generation LED-curing lights may not be suitable to ensure sufficient conversion of all types of nanocomposites at depths of 2 mm.
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Hussain M, Wang Y. Influence of prolonged light-curing time on the shear bonding strength of resin to bleached enamel. Oper Dent 2010; 35:672-81. [PMID: 21180007 DOI: 10.2341/10-095-l] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study evaluated the effect of prolonged light-curing time using a light-emitting diode unit (LED) on the shear bond strength of a resin composite to enamel immediately after bleaching. The enamel surfaces of human molars were divided into four groups: one control and three bleaching groups. One bleaching group (CP) was exposed to a 10% carbamide peroxide bleaching agent and bonded after 24 hours. The other two bleaching groups (HP) were bleached with a 38% hydrogen peroxide bleaching agent, then bonded either within one hour (HPA) or after 24 hours (HPB). All groups were subdivided into two subgroups and cured for two different times (20 or 40 seconds) with an LED unit. Shear bond strength (SBS) was tested with a universal-testing machine and the data were analyzed by ANOVA and post-hoc tests. Scanning electron micrographs of representative specimens were taken. A significant difference was seen between the control and HPA groups for both curing times (p = 0.000). However, neither the CP nor HPB groups showed any significant differences compared with the control groups (p > 0.05). Two-way ANOVA showed that a significant effect of the curing time factor was recorded for all groups (p = 0.000). Prolonged curing time, using an LED unit with a light intensity of 500 mW/cm2, increased resin-enamel bonding strengths for the control and bleached groups when bonding was performed after 24 hours of immersion in deionized water. However, the SBS was still compromised when bonding was performed immediately to enamel bleached with 38% HP.
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Affiliation(s)
- Manal Hussain
- School and Hospital of Stomatology, Wuhan University, Wuhan, Republic of China
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Souza-Junior EJ, Prieto LT, Soares GP, Dias CTDS, Aguiar FHB, Paulillo LAMS. The effect of curing light and chemical catalyst on the degree of conversion of two dual cured resin luting cements. Lasers Med Sci 2010; 27:145-51. [PMID: 21104286 DOI: 10.1007/s10103-010-0857-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 10/28/2010] [Indexed: 10/18/2022]
Abstract
The aim of this study was to evaluate the influence of different curing lights and chemical catalysts on the degree of conversion of resin luting cements. A total of 60 disk-shaped specimens of RelyX ARC or Panavia F of diameter 5 mm and thickness 0.5 mm were prepared and the respective chemical catalyst (Scotchbond Multi-Purpose Plus or ED Primer) was added. The specimens were light-cured using different curing units (an argon ion laser, an LED or a quartz-tungsten-halogen light) through shade A2 composite disks of diameter 10 mm and thickness 2 mm. After 24 h of dry storage at 37°C, the degree of conversion of the resin luting cements was measured by Fourier-transformed infrared spectroscopy. For statistical analysis, ANOVA and the Tukey test were used, with p ≤ 0.05. Panavia F when used without catalyst and cured using the LED or the argon ion laser showed degree of conversion values significantly lower than RelyX ARC, with and without catalyst, and cured with any of the light sources. Therefore, the degree of conversion of Panavia F with ED Primer cured with the quartz-tungsten-halogen light was significantly different from that of RelyX ARC regardless of the use of the chemical catalyst and light curing source. In conclusion, RelyX ARC can be cured satisfactorily with the argon ion laser, LED or quartz-tungsten-halogen light with or without a chemical catalyst. To obtain a satisfactory degree of conversion, Panavia F luting cement should be used with ED Primer and cured with halogen light.
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Affiliation(s)
- Eduardo José Souza-Junior
- Piracicaba Dental School, Department of Restorative Dentistry, University of Campinas-UNICAMP, Piracicaba, SP, Brazil.
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Efficiency of light-emitting diode and halogen units in reducing residual monomers. Am J Orthod Dentofacial Orthop 2010; 138:617-22. [PMID: 21055603 DOI: 10.1016/j.ajodo.2008.10.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 09/01/2008] [Accepted: 09/01/2008] [Indexed: 11/22/2022]
Abstract
INTRODUCTION In this in-vitro study, we aimed to compare the residual monomers in composites beneath brackets bonded to enamel, using a light-emitting diode (LED) or a halogen unit, and to compare the residual monomers in the central to the peripheral areas of the composite. METHODS Twenty bovine teeth preserved in 0.1% thymol were used in this study. Ten teeth were used to standardize the thickness of the composite film, since different thicknesses would cause different absorbance of light. Brackets were bonded to 10 bovine incisors, with the halogen light (n = 5) and the LED (n = 5). The brackets were debonded, and the remaining composite on the enamel surface was sectioned in 2 regions: peripheral (0.8 mm) and central, resulting in 2 subgroups per group: central halogen (n = 5), peripheral halogen (n = 5), central LED (n = 5), and peripheral LED (n = 5). The spectrometric analysis in the infrared region was used to measure the free monomers with the attenuated total reflectance method. RESULTS Normal distribution was tested by using the Kolmogorov-Smirnov test. Data were compared by 2-way analysis of variance (ANOVA) at P <0.05. The LED group showed fewer residual monomers than did the halogen group (P = 0.014). No differences were found among the regions (P = 0.354), and there were no interactions between light type and region (P = 0.368). CONCLUSIONS LED leaves less residual monomer than does the halogen light, even with half of the irradiation time; there were no differences between the central and peripheral regions, and no interaction between light type and region.
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Rahiotis C, Patsouri K, Silikas N, Kakaboura A. Curing efficiency of high-intensity light-emitting diode (LED) devices. J Oral Sci 2010; 52:187-95. [PMID: 20587941 DOI: 10.2334/josnusd.52.187] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
We evaluated the curing efficiency of 4 high-intensity light-emitting diode (LED) devices by assessing percentage of residual C=C (%RDB), surface microhardness (SM), depth of cure (DC), percentage of linear shrinkage-strain (%LS), and percentage of wall-to-wall contraction (%WWC). The light-curing units tested were a QTH light, the Elipar TriLight (3M/ESPE), and 4 LED devices - the Allegro (Denmat), the Bluephase (Ivoclar/Vivadent), the FreeLight2 (3M/ESPE), and The Cure TC-01 (Spring Health Products). The %RDB was measured by microFTIR spectroscopy. Microhardness measurements (Vickers) were performed at the surface (H0) and at depths of 3 mm (H3) and 5 mm (H5) of cylindrical specimens. Depth of cure was expressed as the ratio of microhardness at each depth, relative to the corresponding surface value (H3/H0 and H5/H0). The bonded disc method was used to evaluate %LS. For the %WWC evaluation, cylindrical resin restorations were imaged by high resolution micro-CT and the %WWC was calculated at depths of 0 mm and 2 mm. There were no statistical differences among the LEDs in %RDB or %LS. The Bluephase and Allegro had the highest SM values. As compared with the other LEDs, the Bluephase and The Cure TC-01 had lower values for depth of cure at depths of 3 mm and 5 mm. There were no significant differences in %WWC among the LEDs at either depth, and the QTH had the lowest %WWC at both depths.
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Affiliation(s)
- Christos Rahiotis
- Department of Oral Biology, Faculty of Dentistry, University of Athens, Goudi, Greece.
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Ikemura K, Endo T. A review of the development of radical photopolymerization initiators used for designing light-curing dental adhesives and resin composites. Dent Mater J 2010; 29:481-501. [PMID: 20859059 DOI: 10.4012/dmj.2009-137] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This paper reviews our recent studies on radical photopolymerization initiators, which are used in the design of light-curing dental adhesives and resin composites, by collating information of related studies from original scientific papers, reviews, and patent literature. The photopolymerization reactivities of acylphosphine oxide (APO) and bisacylphosphine oxide (BAPO) derivatives, and D,L-camphorquinone (CQ)/tertiary amine were investigated, and no significant differences in degree of conversion (DC) were found between BAPO and CQ/amine system (p>0.05). In addition, a novel 7,7-dimethyl-2,3-dioxobicyclo[2.2.1]heptane-1-carbonyldiphenyl phosphine oxide (DOHC-DPPO=CQ-APO) was synthesized and its ultraviolet and visible (UV-VIS) spectral behavior was investigated. CQ-APO possessed two maximum absorption wavelengths (λmax) at 350-500 nm [372 nm (from APO group) and 475 nm (from CQ moiety)], and CQ-APO-containing resins exhibited good photopolymerization reactivity, excellent color tone, relaxed operation time, and high mechanical strength. It was also found that a newly synthesized, water-soluble photoinitiator (APO-Na) improved adhesion to ground dentin.
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Affiliation(s)
- Kunio Ikemura
- Department of Research and Development, Shofu Inc., 11 Kamitakamatsu-cho, Fukuine, Higashiyama-ku, Kyoto 605-0983, Japan.
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Retamoso LB, Onofre NML, Hann L, Marchioro EM. Effect of light-curing units in shear bond strength of metallic brackets: an in vitro study. J Appl Oral Sci 2010; 18:68-74. [PMID: 20379684 PMCID: PMC5349030 DOI: 10.1590/s1678-77572010000100012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 08/11/2009] [Indexed: 12/03/2022] Open
Abstract
Objective To determine the influence of the light curing units on the shear bond strength of
orthodontic brackets. Material and Methods Seventy-two premolars were divided into six groups (n=12): Group I: brackets
bonded with Transbond and polymerization with halogen light; Group II: Transbond
and LED; Group III: Fuji Ortho and halogen light; Group IV: Fuji Ortho and LED;
Group V: Fuji Ortho, without acid and halogen light; Group VI: Fuji Ortho, without
acid and LED. The groups were tested to shear strength in a universal testing
machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by
ANOVA and Tukey’s test. Results The composite resin presented higher shear bond strength than the resin-modified
glass ionomer cement (p<0.05). The halogen light and LED sources produced
similar shear bond strength (p>0.05). Conclusion The shear bond strength was influenced by the material but not by the light-curing
unit. The use of LED reduced the experimental time by approximately 60%, with the
same curing efficiency.
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A dynamic light scattering approach for monitoring dental composite curing kinetics. Dent Mater 2010; 26:634-42. [DOI: 10.1016/j.dental.2010.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 12/14/2009] [Accepted: 03/08/2010] [Indexed: 11/17/2022]
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Dall'Igna CM, Marchioro EM, Spohr AM, Mota EG. Effect of curing time on the bond strength of a bracket-bonding system cured with a light-emitting diode or plasma arc light. Eur J Orthod 2010; 33:55-9. [DOI: 10.1093/ejo/cjq027] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Santos MJMC, Passos SP, da Encarnação MOL, Santos GC, Bottino MA. Hardening of a dual-cure resin cement using QTH and LED curing units. J Appl Oral Sci 2010; 18:110-5. [PMID: 20485920 PMCID: PMC5349745 DOI: 10.1590/s1678-77572010000200003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 10/21/2009] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE This study evaluated the surface hardness of a resin cement (RelyX ARC) photoactivated through indirect composite resin (Cristobal) disks of different thicknesses using either a light-emitting diode (LED) or quartz tungsten halogen (QTH) light source. MATERIAL AND METHODS Eighteen resin cement specimens were prepared and divided into 6 groups according to the type of curing unit and the thickness of resin disks interposed between the cement surface and light source. Three indentations (50 g for 15 s) were performed on the top and bottom surface of each specimen and a mean Vickers hardness number (VHN) was calculated for each specimen. The data were analyzed using two-way ANOVA and Tukey-Kramer test was used for post-hoc pairwise comparisons. RESULTS Increased indirect resin disk thickness resulted in decreased mean VHN values. Mean VHN values for the top surfaces of the resin cement specimens ranged from 23.2 to 46.1 (QTH) and 32.3 to 41.7 (LED). The LED curing light source produced higher hardness values compared to the QTH light source for 2- and 3-mm-thick indirect resin disks. The differences were clinically, but not statistically significant. Increased indirect resin disk thickness also resulted in decreased mean VHN values for the bottom surfaces of the resin cement: 5.8 to 19.1 (QTH) and 7.5 to 32.0 (LED). For the bottom surfaces, a statistically significant interaction was also found between the type of curing light source and the indirect resin disk thickness. CONCLUSION Mean surface hardness values of resin cement specimens decreased with the increase of indirect resin disk thickness. The LED curing light source generally produced higher surface hardness values.
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Di Nicoló R, Araujo MAMD, Alves LAC, Souza RODAE, Rocha DMD. Shear bond strength of orthodontic brackets bonded using halogen light and light-emitting diode at different debond times. Braz Oral Res 2010; 24:64-9. [DOI: 10.1590/s1806-83242010000100011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 06/24/2009] [Indexed: 11/22/2022] Open
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Hegde MN, Hegde P, Malhan B. Evaluation of depth of cure and knoop hardness in a dental composite, photo-activated using different methods. J Conserv Dent 2010; 11:76-81. [PMID: 20142889 PMCID: PMC2813097 DOI: 10.4103/0972-0707.44055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 02/02/2008] [Accepted: 02/22/2008] [Indexed: 11/06/2022] Open
Abstract
The study aimed at evaluating the depth of cure and knoop hardness of a microfine-hybrid composite resin that was photo-activated using different methods. A bipartite brass mold was filled with composite resin and photo-activation was performed using four methods: (1) Intermittent method using quartz tungsten halogen (QTH) light curing unit (LCU) (2) Continuous method (QTH) (3) Exponential method (QTH) (4) Continuous method using light-emitting diode (LED). Depth of cure was measured at the unexposed bottom surface of the specimen using microtester as a penetrometer. The surfaces exposed to light were subjected to knoop hardness testing, using a digital microhardness tester. Knoop hardness measurements were obtained at the top surface and at depths of 1, 2, 3, 4 and 5 mm. The data was analyzed using anova and Tukey's test (5%). Results showed that the depth of cure was higher with the intermittent method (QTH), followed by the continuous method (QTH), the exponential method and the continuous method (LED). At the top surface and up to 1 mm, continuous method (LED) demonstrated the highest knoop hardness number (KHN). At 2 mm and up to 5 mm, intermittent method (QTH) presented the highest KHN and continuous method (LED) showed the lowest KHN. At all depths, continuous method (QTH) showed higher KHN, as compared to the exponential method (QTH), except at 2 mm where both showed no significant difference.
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Affiliation(s)
- Mithra N Hegde
- Department of Conservative Dentistry and Endodontics, A. B. Shetty Memorial Institute of Dental Sciences, Deralakatte, Mangalore, Karnataka, India
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