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Al-Zain AO, Al-Ghamdi ZA, Basahal MM, Al-Bukhary RM, Münchow E. Performance of Multiple Light-curing Units used by Dental Students. Open Dent J 2020. [DOI: 10.2174/1874210602014010671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aim:
To investigate the performance of multiple Light-curing Units (LCUs) of different manufacturers used in a dental student clinical setting.
Background:
Manufacturers claim that the irradiance values of the LCUs stay stable over time. However, this may not be accurate among the different units.
Objective:
This study investigated the performance in terms of the irradiance, radiant exposure, and DOC of multiple LCUs of different types used in a dental student clinical setting.
Methods:
Four different LCU were investigated (n=5 units/LCU manufacturer): three Light-Emitting-Diodes (LED) units (Demi Ultra, Mini LED, and E-Morlit) and one quartz-tungsten-halogen (QTH) (PolyluxII). Irradiance and radiant exposure were collected [Managing Accurate Resin Curing-Patient Simulator (MARC-PS)](n=5 readings/unit/tooth). Depth of Cure (DOC) was performed (ISO 4049:2009standards) using a micro-hybrid composite (n=5/unit). Data were analyzed using Kruskal-Wallis and ANOVA followed by Student-Newman-Keuls and Tukey post hoc methods, respectively (α=0.05).
Results:
Using the MARC-PS anterior and posterior teeth sensors, respectively, the mean irradiance for Demi Ultra was (1625.7±38.8) and (1250.4±25.2); Mini LED (1381.1±37.8) and (1058.1±27.3); E-Morlit (1831.1±294.7) and (1545.2±176.0); and Polylux II (932.4±368.5) and (840.4±353.4)mW/cm2. The radiant exposure range was 16-38 J/cm2 for all LCUs. LCUs’ mean DOC ranged from 2.9 to 3.1 mm. Significant differences in irradiance and radiant exposure values were detected among the multiple units and manufacturers. Significant differences in DOC values among the Demi Ultra and Polylux II units were detected. DOC met the standards except for onePolylux II unit.
Conclusion:
The irradiance and radiant exposure values were not the same among the different units, regardless of the manufacturers’ claim of the irradiance values stability over time. Polymerization was not compromised except for one QTH unit per the DOC measurements. Itis highly recommended to closely monitor LCUs used in dental student clinical areas due to the high demand in this type of setting.
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Mayinger F, Reymus M, Liebermann A, Richter M, Kubryk P, Großekappenberg H, Stawarczyk B. Impact of polymerization and storage on the degree of conversion and mechanical properties of veneering resin composites. Dent Mater J 2020; 40:487-497. [PMID: 33342921 DOI: 10.4012/dmj.2019-394] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To investigate the degree of conversion (DC), Martens hardness (HM), elastic indentation modulus (EIT), and flexural strength (FS) of veneering resin composites (SR Nexco Paste (NP), Ceramage Incisal (CI), Gradia Plus (GP); n=60/group) cured with different polymerization devices (bre.Lux Power Unit, Labolight DUO, Otoflash G171, LC-3DPrint Box, PCU LED; n=12/subgroup) after storage. Otoflash G171 and Labolight DUO showed increased DC/HM/EIT. CI presented the lowest DC and highest HM/EIT. NP showed the highest DC and lowest HM/EIT. Within Otoflash G171, Laboligth DUO and PCU LED, highest FS was observed for CI. Storage did not affect DC/HM/EIT for specimens cured with Otoflash G171 or Labolight DUO. With storage not showing an influence on the tested parameters for polymerization devices that otherwise presented superior results, increased storage time cannot be recommended. For the tested resin composites, this study observed a high/low degree of conversion to coincide with respectively low/high amounts of fillers/mechanical properties.
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Affiliation(s)
| | - Marcel Reymus
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich
| | - Anja Liebermann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich
| | | | | | | | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich
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Long-Term Stability of a RAFT-Modified Bulk-Fill Resin-Composite under Clinically Relevant Versus ISO-Curing Conditions. MATERIALS 2020; 13:ma13235350. [PMID: 33255830 PMCID: PMC7728365 DOI: 10.3390/ma13235350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 11/17/2022]
Abstract
The addition of RAFT (reversible addition-fragmentation chain transfer) agents to the matrix formulation of a bulk-fill resin composite can significantly decrease the required curing time down to a minimum of 3 s. Evaluating the long term-stability of this resin composite in relation to varied curing conditions in an in-vitro environment was this study’s goal. Specimens were produced according to either an ISO or one of two clinical curing protocols and underwent a maximum of three successive aging procedures. After each one of the aging procedures, 30 specimens for each curing condition were extracted for a three-point bending test. Fragments were then stereo-microscopically characterized according to their fracture mechanism. Weibull analysis was used to quantify the reliability of each aging and curing combination. Selected fragments (n = 12) underwent further testing via depth-sensing indentation. Mechanical values for either standardized or clinical curing were mostly comparable. However, changes in fracture mechanism and Weibull modulus were observed after each aging procedure. The final procedure exposed significant differences in the mechanical values due to curing conditions. Curing conditions with increased radiant exposure seemingly result in a higher crosslink in the polymer-matrix, thus increasing resistance to aging. Yet, the clinical curing conditions still resulted in acceptable mechanical values, proving the effectiveness of RAFT-polymerization.
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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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55
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Geng T, Pan Y, Liu ZZ, Yuan C, Wang P, Meng X. Time-dependent Microhardness Gradients of Self-adhesive Resin Cements Under Dual- and Self-curing Modes. Oper Dent 2020; 45:E280-E288. [PMID: 33215201 DOI: 10.2341/19-006-l] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2019] [Indexed: 11/23/2022]
Abstract
CLINICAL RELEVANCE Acid-functional monomers in self-adhesive resin cements may decrease their self-curing polymerization ability. Light irradiation optimizes polymerization performance. SUMMARY Purpose: The aim of this study was to investigate Knoop microhardness of self-adhesive resin cements under dual- and self-curing modes in simulated canals for describing the polymerization behavior.Methods and Materials: Slots in lightproof silicone cylinders with one open end were filled with the following eight materials: a traditional resin cement (Duolink), a core build-up resin material (MultiCore Flow), and six self-adhesive resin cements (RelyX Unicem 2, G-Cem Automix, Maxcem, Biscem, Multilink Speed, and PermaCem 2.0). The resins were exposed to light through the open end and then stored in a lightproof box. The Knoop hardness gradient for each resin was measured after 1 hour and 120 hours. Surface readings were obtained at 1-mm intervals from 1 mm to 10 mm away from the open ends. The data were analyzed by two-way analysis of variance and the Student-Newman-Keuls test (α=0.05).Results: All the resin materials had stable Knoop hardness numbers (KHNs) at a certain depth; their KHNs in the self-curing mode did not change (p>0.05). The region above this certain depth was regarded as having undergone the dual-curing mode, and the KHN decreased gradually with depth (p<0.05). Between 1 and 120 hours postexposure, the ratio of the KHN at a 5-mm depth (self-cured) to that at a 1-mm depth (dual-cured) increased in Duolink and MultiCore Flow. However, the ratios of the six adhesive resin cements varied.Conclusion: Without light, most self-adhesive resin cements differed from traditional dual-cured resin materials in terms of Knoop micro-hardness, and they had a lesser capacity for chemical-induced curing.
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Aung SZ, Takagaki T, Ikeda M, Nozaki K, Burrow MF, Abdou A, Nikaido T, Tagami J. The effect of different light curing units on Vickers microhardness and degree of conversion of flowable resin composites. Dent Mater J 2020; 40:44-51. [PMID: 32848103 DOI: 10.4012/dmj.2019-353] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study aimed to assess the influence of different light curing units (LCUs) on the polymerization of various flowable resin composites. Three LCUs (Optilux 501, Elipar™ DeepCure-L LED and Bluephase®20i) and eight flowable resin composites: MI FIL Flow, Estelite Flow Quick, Estelite Universal Flow (medium), Estelite Universal Flow (super low), Beautifil Flow Plus, Clearfil Majesty ES Flow, Filtek Supreme Ultra flowable and TetricEvo Flow were tested. For Vickers microhardness (VHN) test and degree of conversion (DC), specimens were prepared and polymerized for 20 s. VHN test was performed at top surfaces (3 indentations) and DC for each specimen was measured using Fourier transform infrared (FT-IR) spectroscopy after 24 h dry storage in dark at 37˚C. The data were analyzed with 2-way ANOVA and t-test with Bonferroni correction. DC and hardness values showed a relationship between materials and LCUs. The curing efficacy of LCU type may depend on the material composition.
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Affiliation(s)
- Swe Zin Aung
- Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Tomohiro Takagaki
- Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.,Department of Operative Dentistry, Division of Oral Functional Sciences and Rehabilitation, School of Dentistry, Asahi University
| | - Masaomi Ikeda
- Oral Prosthetic Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Kosuke Nozaki
- Department of Biofunction Research, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental Universit
| | - Michael F Burrow
- Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital
| | - Ahmed Abdou
- Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Toru Nikaido
- Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University.,Department of Operative Dentistry, Division of Oral Functional Sciences and Rehabilitation, School of Dentistry, Asahi University
| | - Junji Tagami
- Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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Watts DC, Algamaiah H. Characterizing surface viscoelastic integrity of ultra-fast photo-polymerized composites: Methods development. Dent Mater 2020; 36:1255-1265. [PMID: 32819731 DOI: 10.1016/j.dental.2020.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/28/2020] [Accepted: 07/28/2020] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Resin-Composites are now available designed for polymerization using 3 s of intense light irradiation. The aim was to develop an experimental method to probe their surface viscoelastic integrity immediately following such rapid photo-cure via macroscopic surface indentation under constant stress as a function of time. METHODS Two bulk-fill composites (Ivoclar AG) were studied: Tetric PowerFill (PFill) and PowerFlow (PFlow). Split molds were used to fabricate cylindrical {4 mm (dia) × 4 mm} paste specimens, irradiated at 23 °C at 0 mm from the top surface with a BluephasePowerCure LED-LCU, with 3 s or 5 s modes, emitting 3 and 2 W/cm2, respectively. Post-irradiation specimens were immediately transferred to an apparatus equipped with a flat-ended indentor of 1.5 mm diameter. 14 MPa compressive stress at the indentor tip was applied centrally in < 2 min and maintained constant for 2 h. Indentation (I) magnitudes were recorded in real-time (t), with I(t) data re-expressed as % indentation relative to the 4 mm specimen height. After 2 h, the indentor was unloaded and indentation recovery was monitored for a further 2 h. Parallel sets of measurements were made where indentation was delayed for 24 h. Further measurements were made with more conventional composites: EvoCeram Bulk Fill (ECeram) and Tetric EvoFlow Bulk Fill (EFlow). These were irradiated for 20 s at 1.2 W/cm2. Kinetic data were curve-fitted to exponential growth functions and key parameters analyzed by ANOVA and post-hoc tests (α = 0.05). RESULTS I(t) plots looked initially similar to bulk creep/recovery: rapid deformation plus viscoelastic response; then, upon unloading: rapid (elastic) recovery followed by partial viscoelastic recovery. However, unlike multiply irradiated and stored bulk-creep specimens, the present specimens were exposed to only 3 or 5 s "occlusal" irradiation; generating "hard" surfaces. Subsequently, during the 2 h indentation, the polymer matrix network continued to harden and consolidate. Upon initial loading, I(t) reached 2-3% indentation, depending upon the formulation. Upon unloading at 2 h, elastic recovery was only ca. 1 %. Delayed loading for 24 h, generated I(t) plots of significantly reduced magnitude. Most importantly, however, the I(t) plots for ECeram and EFlow, after 20 s irradiation, showed I(t) magnitudes quite comparable to the PFill and PFlow rapid-cure composites. SIGNIFICANCE Macroscopic indentation creep has been shown to be a workable procedure that can be applied to rapid-cure materials to assess their immediate surface integrity and developing viscoelastic characteristics. The applied stress of 14 MPa was relatively severe and the indentation/recovery profiles of PowerFill materials with only 3 or 5 s irradiation demonstrated comparability with their established 20 s cure siblings, evidencing the suitability of the PowerCure system for clinical application.
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Affiliation(s)
- David C Watts
- Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Photon Science Institute, University of Manchester, UK.
| | - Hamad Algamaiah
- Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Department of Restorative Dental Science, College of Dentistry, King Saud University, Saudi Arabia.
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58
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Wikant AW, Gedde UW, Hakeberg M, Örtengren UT. Suboptimal light curing and direct exposure to water of two contemporary composites: degree of conversion, sorption, solubility, and Knoop hardness. Eur J Oral Sci 2020; 128:345-353. [DOI: 10.1111/eos.12705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2020] [Indexed: 12/01/2022]
Affiliation(s)
- Aksel W. Wikant
- Department of Clinical Dentistry Faculty of Health Sciences Tromsø University Tromsø Norway
| | - Ulf W. Gedde
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Fibre and Polymer Technology KTH Royal Institute of Technology Stockholm Sweden
| | - Magnus Hakeberg
- Department of Behavioural and Community Dentistry Institute of Odontology/Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
| | - Ulf T. Örtengren
- Department of Clinical Dentistry Faculty of Health Sciences Tromsø University Tromsø Norway
- Department of Cariology Institute of Odontology/Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
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Soyland R, Currier GF, Kadioglu O, Li J, Esteban Florez FL, Rueggeberg FA, Khajotia SS. Pairing orthodontic adhesive resins and light-curing units for optimal degree of conversion. J World Fed Orthod 2020; 9:68-74. [PMID: 32672657 DOI: 10.1016/j.ejwf.2020.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/03/2020] [Accepted: 02/11/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The purpose of this study was to identify the combination of orthodontic adhesive resins and light-emitting diode (LED) light-curing units (LCUs) that result in the highest degree of resin conversion (DC). The hypothesis tested was that pairing orthodontic resins with LCUs from the same manufacturer produces higher DC versus unpaired resins and LCUs. METHODS Pre-polymerization spectra of adhesive resins (Transbond XT [3M Unitek], BracePaste [American Orthodontics] or Opal Bond MV [Opal by Ultradent]) were obtained at oral temperature (37°C) using an attenuated total reflectance (ATR) diamond crystal (Golden Gate, Specac) in a Fourier-transform infrared (FTIR) spectrometer (Nicolet IS50). Resin specimens were polymerized using various LCUs (Ortholux Luminous [3M Unitek], Blue Ray 3 [American Orthodontics], or VALO Ortho Cordless [Ultradent Products, Inc.]) before obtaining post-polymerization infrared (IR); spectra. Twelve LCU-resin combinations were tested (n = 20/combination), half with a bracket present (Mini Diamond Twin, Ormco) and half without. DC values (%) were calculated using the two-frequency method and tangent-baseline technique. Data for each resin were statistically analyzed using General Linear Models and Student-Newman-Keuls post hoc tests (α = 0.05). RESULTS Statistically significant differences were found within each resin for the groups without brackets present (P < 0.0001), the groups with brackets present (P < 0.0001), and the groups with brackets when compared with the manufacturer-paired group without a bracket (P < 0.0001). CONCLUSIONS Adhesive resins and LCUs from the same manufacturer did not consistently result in statistically higher mean DC values than unpaired combinations. Metal brackets do not uniformly reduce the degree of conversion of adhesive resins when assessed using IR spectrometry.
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Affiliation(s)
- Rachel Soyland
- Graduate Orthodontics Program, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - G Frans Currier
- Program Chair, Division of Orthodontics, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Onur Kadioglu
- Graduate Program Director, Division of Orthodontics, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Ji Li
- Research Biostatistician, Hudson College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Fernando L Esteban Florez
- Assistant Professor, Division of Dental Biomaterials, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Frederick A Rueggeberg
- Professor and Director, Section of Dental Materials, Department of Restorative Sciences, The Dental College of Georgia at Augusta University, Augusta, Georgia
| | - Sharukh S Khajotia
- Professor and Head, Division of Dental Biomaterials, College of Dentistry, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.
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Mokbel H, Graff B, Dumur F, Lalevée J. NIR Sensitizer Operating under Long Wavelength (1064 nm) for Free Radical Photopolymerization Processes. Macromol Rapid Commun 2020; 41:e2000289. [PMID: 32638497 DOI: 10.1002/marc.202000289] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/23/2020] [Indexed: 01/29/2023]
Abstract
Free radical polymerization upon near-infrared (NIR) light is still the subject of intense research efforts and remains a huge challenge particularly for long wavelengths (>1000 nm). In this study, a NIR sensitizer operating upon long wavelength (1064 nm) is proposed for an efficient polymerization of acrylate monomers. A new three-component photoinitiating system is developed comprising the NIR sensitizer in combination with an Iodonium salt (Iod) and an amine. Remarkably, the NIR sensitizer (IR 1064) absorbing strongly in all the near infrared region (700-1200 nm) offers the possibility to use a broad range of irradiation wavelengths, i.e., examples are provided at 785 and 1064 nm. Such long wavelengths are characterized by many advantages such as a deeper penetration of light and therefore a better curing of the monomer but it is also much safer than UV light. Excellent performance is observed for the three-component IR 1064/Iod/Amine system under air: high conversion of acrylate functions associated with a fast polymerization time. The use of IR 1064 as NIR sensitizer with a broad NIR absorption is-to the best of current knowledge-never proposed in the literature. The photoinitiating performances are studied using real-time Fourier transform infrared spectroscopy.
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Affiliation(s)
- Haifaa Mokbel
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, Mulhouse, F-68100, France.,Université de Strasbourg, Strasbourg, 67000, France
| | - Bernadette Graff
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, Mulhouse, F-68100, France.,Université de Strasbourg, Strasbourg, 67000, France
| | - Frédéric Dumur
- Aix Marseille Univ, CNRS, ICR UMR 7273, Marseille, F-13397, France
| | - Jacques Lalevée
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, Mulhouse, F-68100, France.,Université de Strasbourg, Strasbourg, 67000, France
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New bio-sourced hydrogen donors as high performance coinitiators and additives for CQ-based systems: Toward aromatic amine-free photoinitiating systems. Eur Polym J 2020. [DOI: 10.1016/j.eurpolymj.2020.109794] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Improved Fracture Toughness and Conversion Degree of Resin-Based Dental Composites after Modification with Liquid Rubber. MATERIALS 2020; 13:ma13122704. [PMID: 32545845 PMCID: PMC7344604 DOI: 10.3390/ma13122704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/05/2020] [Accepted: 06/11/2020] [Indexed: 11/17/2022]
Abstract
There are many methods widely applied in the engineering of biomaterials to improve the mechanical properties of the dental composites. The aim of this study was to assess the effect of modification of dental composites with liquid rubber on their mechanical properties, degree of conversion, viscosity, and cytotoxicity. Both flow and packable composite consisted of a mixture of Bis-GMA, TEGDMA, UDMA, and EBADMA resins reinforced with 60 and 78 wt.% ceramic filler, respectively. It was demonstrated that liquid rubber addition significantly increased the fracture toughness by 9% for flow type and 8% for condensable composite. The influence of liquid rubber on flexural strength was not statistically significant. The addition of the toughening agent significantly reduced Young’s modulus by 7% and 9%, respectively, while increasing deformation at breakage. Scanning electron microscopy (SEM) observations allowed to determine the mechanisms of toughening the composites reinforced with ceramic particles. These mechanisms included bridging the crack edges, blocking the crack tip by particles and dissipation of fracture energy by deflection of the cracks on larger particles. The degree of conversion increased after modification, mainly due to a decrease in the matrix resin viscosity. It was also shown that all dental materials were nontoxic according to ISO 10993-5, indicating that modified materials have great potential for commercialization and clinical applications.
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63
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Limited reciprocity in curing efficiency of bulk-fill resin-composites. Dent Mater 2020; 36:997-1008. [PMID: 32499190 DOI: 10.1016/j.dental.2020.04.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/29/2020] [Accepted: 04/29/2020] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The aim of the study was to identify experimental limits of the general reciprocity hypothesis that the same photo-cure outcomes will result from applying essentially constant energy densities, despite reciprocal variations in the irradiance and irradiation time-period, for a representative set of bulk fill (BF) and non-BF resin composites. METHODS Six BF and two non-BF resin-composites were selected. The unset pastes were inserted into white acetal molds (5mm id) with (n=6) depths (1, 2, 3, 4, 5 and 6mm). Three light curing units (LCUs) of increasing radiant emittance capability: 1200, 2000 and 3200mW/cm2 were used. Composite specimen groups (n=3, per depth, per LCU) were irradiated on the upper surface only. For each specific composite, the irradiation times for each LCU were reduced reciprocally, as the LCU irradiance increased, to deliver a constant energy density (J/cm2) to that composite. However, the required energy density for a given composite differed in accordance with each composite manufacturer recommendations. After storing for 24h at 37°C, light transmission measurements were made through each specimen and re-expressed as Apparent Absorbance (A'). Vickers hardness (HV) measurements (n=10) were made on both top and bottom surfaces, for each specimen, and HVversus "depth" profile plots created. From the top-surface data, a Depth-of-Cure parameter could be derived. Data were statistically evaluated for differences between top and bottom HV values and for other predefined variables of interest. RESULTS Irradiation with the LCU of 1200mW/cm2 generally gave the highest HV/depth for most materials tested compared to the other curing lights with higher power output, regardless of top and bottom measurements (p<0.001). However, this difference was material-dependent. With one BF composite, 1200 and 2000mW/cm2 irradiance did not show a significant difference between top and bottom HV. Composites with higher translucency showed reduced differences in top/bottom HV than more opaque composites. SIGNIFICANCE Reciprocity was found to be limited with most materials examined, such that irradiance periods of 10s, gave generally better HV outcomes than by using LCUs of superior radiant emittance while reciprocally reducing irradiance time to maintain constant dose of energy density.
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Fakhari A, Heshmat H, Emami Arjomand M, Tabatabaei SF. Influence of Light-Curing Units on Color Stability of Composite Resins After Aging. JOURNAL OF RESEARCH IN DENTAL AND MAXILLOFACIAL SCIENCES 2020. [DOI: 10.29252/jrdms.5.2.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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65
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González-López JA, Pérez-Mondragón AA, Cuevas-Suárez CE, Trejo-Carbajal N, Herrera-González AM. Evaluation of dental composites resins formulated with non-toxic monomers derived from catechol. J Mech Behav Biomed Mater 2020; 104:103613. [DOI: 10.1016/j.jmbbm.2019.103613] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/30/2019] [Accepted: 12/31/2019] [Indexed: 10/25/2022]
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66
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Ilie N, Watts DC. Outcomes of ultra-fast (3 s) photo-cure in a RAFT-modified resin-composite. Dent Mater 2020; 36:570-579. [DOI: 10.1016/j.dental.2020.02.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 11/28/2022]
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67
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Gallastegui A, Spada RM, Cagnetta G, Ponzio RA, Martínez SR, Previtali CM, Gómez ML, Palacios RE, Chesta CA. Conjugated Polymer Nanoparticles as Unique Coinitiator-Free, Water-Soluble, Visible-Light Photoinitiators of Vinyl Polymerization. Macromol Rapid Commun 2020; 41:e1900601. [PMID: 32053268 DOI: 10.1002/marc.201900601] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/09/2020] [Indexed: 12/13/2022]
Abstract
The use of conjugated polymer nanoparticles (CP NPs) of poly(9,9-dioctylfluorene-alt-benzothiadiazole) and poly(9,9-di-n-octylfluorenyl-2,7-diyl) as efficient photoinitiator systems (PIS) of vinyl polymerization in water is reported herein. CP NPs are biocompatible, excitable with blue commercial LEDs and, unlike visible light Type II PIS, do not need co-initiators to trigger a monomer chain reaction. CP NPs photoinitiate polymerization of a variety of acrylic monomers with initiation rates comparable to those observed for well-known Type II PIS. Given the extraordinarily large molar absorption coefficients of CP NPs (≈108 m-1 cm-1 ) very low particle concentration is required for effective polymerization. Additionally, CP NPs behave as conventional macrophotoinitiators significantly reducing contamination risks due to leaching of low molecular weight byproducts. These combined features make CP NPs PIS suitable to synthesize polymeric materials for many healthcare and biomedical applications including drug delivery, tissue engineering, prosthetic implants, and food/medicine packaging. These CP NPs PIS are also used to synthesize nano-hydrogels with a relatively narrow and controlled size distribution in the absence of surfactants. It is proposed that polymerization is initiated at the CP NPs surface by photogenerated free polarons, in close analogy to the mechanism previously described for PIS based on inorganic semiconductor NPs.
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Affiliation(s)
- Antonela Gallastegui
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
| | - Ramiro M Spada
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
| | - Gonzalo Cagnetta
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
| | - Rodrigo A Ponzio
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
| | - Sol R Martínez
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
| | - Carlos M Previtali
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
| | - María Lorena Gómez
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
| | - Rodrigo E Palacios
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
| | - Carlos A Chesta
- Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados (IITEMA), Universidad Nacional de Río Cuarto (UNRC) and Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Campus Universitario, 5800, Río Cuarto, Argentina
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Surke C, Meier R, Haug L, Vögelin E. Osteosynthesis of fifth metacarpal neck fractures with a photodynamic polymer bone stabilization system. J Hand Surg Eur Vol 2020; 45:119-125. [PMID: 31635518 DOI: 10.1177/1753193419880775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Metacarpal neck fractures with severe displacement are commonly treated surgically with intramedullary Kirschner wires. We present the results of treatment of fifth metacarpal neck fractures using a light curable intramedullary photodynamic polymer (IlluminOss™, IlluminOss Medical Inc., East Providence, RI, USA). Twenty-nine patients with isolated displaced fifth metacarpal neck fractures were included and followed up for 12-24 weeks. All fractures had radiologically healed after 3 months. In two cases, a secondary loss of reduction was seen, which did not require further correction. During the follow-up period, range of motion of the metacarpophalangeal joint was 89% after 6 weeks and increased to 100% after 3 months compared with the uninjured side. Grip strength improved over time from 61% to 85%. No implant removal was necessary. We conclude that osteosynthesis using an intramedullary photodynamic polymer is a reliable treatment option for displaced fractures of the fifth metacarpal neck. Level of evidence: IV.
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Affiliation(s)
- Carsten Surke
- Department of Plastic and Hand Surgery, University Hospital Bern, Bern, Switzerland
| | - Rahel Meier
- Department of Plastic and Hand Surgery, University Hospital Bern, Bern, Switzerland
| | - Luzian Haug
- Department of Plastic and Hand Surgery, University Hospital Bern, Bern, Switzerland
| | - Esther Vögelin
- Department of Plastic and Hand Surgery, University Hospital Bern, Bern, Switzerland
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Assaf C, Fahd JC, Sabbagh J. Assessing Dental Light-curing Units' Output Using Radiometers: A Narrative Review. J Int Soc Prev Community Dent 2020; 10:1-8. [PMID: 32181215 PMCID: PMC7055336 DOI: 10.4103/jispcd.jispcd_407_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 11/04/2019] [Indexed: 12/31/2022] Open
Abstract
Introduction This review aimed to describe dental radiometers and discuss their effectiveness compared to other light-testing devices. Materials and Methods The search for light-curing units (LCUs), radiometers, and other light-measuring tools available on the market was accomplished on data found on PubMed, Wikipedia, and Google. Results LCUs are prone to deterioration due to several reasons such as the light's limited life span, the worsening of the LCU's filters, light guide, and light tip end; consequently, decreased photopolymerization and insufficient resin conversion may occur. A regular light output assessment is highly recommended in dental daily practice as well as before any new LCU purchase to make sure the light features meet the factory specifications delivered by the manufacturer and they remained stable through time. Discussion Irradiance values reported by radiometers do not match accurately with those delivered by laboratory power meters. Therefore, dental practitioners as well as dental students are advised to control regularly every LCU by using the same handheld radiometer.
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Affiliation(s)
- Cendrella Assaf
- Department of Restorative and Aesthetic Dentistry, and Endodontics, School of Dentistry, Lebanese University, Hadath Campus, Beirut, Lebanon
| | - Jean-Claude Fahd
- Department of Restorative and Aesthetic Dentistry, and Endodontics, School of Dentistry, Lebanese University, Hadath Campus, Beirut, Lebanon
| | - Joseph Sabbagh
- Department of Restorative and Aesthetic Dentistry, and Endodontics, School of Dentistry, Lebanese University, Hadath Campus, Beirut, Lebanon
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Kirschner J, Paillard J, Graff B, Becht J, Klee JE, Lalevée J. 2‐Oxo‐2(
tert
‐butyldimethylsilyl)Acetic Acid (DKSi‐COOH) as a New Water‐Soluble Visible Light Type I Photoinitiator for Free Radical Polymerization. MACROMOL CHEM PHYS 2020. [DOI: 10.1002/macp.201900495] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Julie Kirschner
- Université de Haute‐Alsace CNRS, IS2M UMR 7361 F‐68100 Mulhouse France
- Université de Strasbourg France
| | - Julien Paillard
- Université de Haute‐Alsace CNRS, IS2M UMR 7361 F‐68100 Mulhouse France
- Université de Strasbourg France
| | - Bernadette Graff
- Université de Haute‐Alsace CNRS, IS2M UMR 7361 F‐68100 Mulhouse France
- Université de Strasbourg France
| | - Jean‐Michel Becht
- Université de Haute‐Alsace CNRS, IS2M UMR 7361 F‐68100 Mulhouse France
- Université de Strasbourg France
| | | | - Jacques Lalevée
- Université de Haute‐Alsace CNRS, IS2M UMR 7361 F‐68100 Mulhouse France
- Université de Strasbourg France
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Influence of Bulk-Fill Composites, Polimerization Modes, and Remaining Dentin Thickness on Intrapulpal Temperature Rise. BIOMED RESEARCH INTERNATIONAL 2019; 2019:4250284. [PMID: 31886213 PMCID: PMC6914950 DOI: 10.1155/2019/4250284] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/23/2019] [Accepted: 11/16/2019] [Indexed: 11/18/2022]
Abstract
Objectives The aim of this study was to compare the effects of different bulk-fill resin composites, polimerization modes, and the thickness of remaining dentin on the increase of intrapulpal temperature. Methods Human-extracted upper premolar teeth (n = 10) were used to design a single-tooth model with remaining dentin thicknesses of 1 mm and 0.5 mm. Estelite Bulk-fill Flow (Tokuyama, Japan), Surefil SDR™ Flow (Dentsply Caulk, Brazil), Filtek Bulk-Fill Posterior (3M, USA), and SonicFill™ 2 Bulk-fill (Kerr, USA) composites were applied according to the manufacturer's instructions. The standard and high modes of a light emitted diode (LED) light curing unit (LCU) (VALO™ Utradent, USA), were used for polymerization. In order to mimic the in vivo conditions of pulpal circulation, digital flowmetry (SK-600II, SK Medical, China) was used. Intrapulpal temperature rise was measured using K type thermocoupling (CEM DT 610B, Robosem Engineering, China). Data were analyzed using three-way variance analysis (ANOVA) and the independent t-test. Results No significant statistical differences in intrapulpal temperature rise between low viscosity bulk-fill composites (SDR and Estelite) were found. The lowest intrapulpal temperature rise was found in groups which used the Filtek Bulk-fill composite. Decreases in the remaining dentin thickness increased the intrapulpal temperature rise. Significance This study demonstrated that remaining dentin thickness, filler ratio of bulk-fill composites, and power and application time of the LED-LCU may affect intrapulpal temperature rise.
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Cardoso IO, Machado AC, Teixeira DNR, Basílio FC, Marletta A, Soares PV. Influence of Different Cordless Light-emitting-diode Units and Battery Levels on Chemical, Mechanical, and Physical Properties of Composite Resin. Oper Dent 2019; 45:377-386. [DOI: 10.2341/19-095-l] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2019] [Indexed: 11/23/2022]
Abstract
Clinical Relevance
Irradiance may decrease as the light-emitting diode (LED) is discharged. Therefore, the LED must be charged carefully to prevent the possibility of influencing the chemical, mechanical, and physical properties of composite resin.
SUMMARY
The aim of this study was to evaluate the influence of different light-emitting diode (LED) curing units and battery levels on the chemical, mechanical, and physical properties of composite resins. The irradiance for each cycle from full to completely discharged battery level was evaluated, for five different new cordless LED units: Optilight Color (Gnatus), Bluephase (Ivoclar), Valo (Ultradent), Radii Plus (SDI), and Radii Xpert (SDI). After the irradiance evaluation, composite resin specimens were prepared and light cured, while varying the battery level for each LED unit: high level (HL, 100%), medium level (ML, 50%), and low level (LL, 10%). The degree of conversion, diametral tensile strength, sorption, and solubility were also evaluated. Data were checked for homoscedasticity and submitted to two-way and three-way analysis of variance, depending on the test performed, followed by the Tukey test with a significance level of 95%. A negative correlation was found between irradiance and cycles of light curing, which was checked by the Pearson correlation test. Valo and Radii Xpert were not influenced by the battery level in any test performed. However, different battery levels for some LED units can influence the degree of conversion, diametral tensile strength, sorption, and solubility of composite resins.
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Kocaarslan A, Kütahya C, Keil D, Yagci Y, Strehmel B. Near‐IR and UV‐LED Sensitized Photopolymerization with Onium Salts Comprising Anions of Different Nucleophilicities. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900170] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Azra Kocaarslan
- Department of Chemistry and Institute for Coatings and Surface ChemistryNiederrhein Univeristy of Applied Sciences Adlerstr. 1 D-47798 Krefeld Germany
- Department of ChemistryIstanbul Technical University Maslak, Ayazaga Campus 34469 Istanbul Turkey
| | - Ceren Kütahya
- Department of Chemistry and Institute for Coatings and Surface ChemistryNiederrhein Univeristy of Applied Sciences Adlerstr. 1 D-47798 Krefeld Germany
| | - Dietmar Keil
- FEW Chemicals GmbHOrtsteil Wolfen Technikumstraße 1 D-06766 Bitterfeld-Wolfen Germany
| | - Yusuf Yagci
- Department of ChemistryIstanbul Technical University Maslak, Ayazaga Campus 34469 Istanbul Turkey
| | - Bernd Strehmel
- Department of Chemistry and Institute for Coatings and Surface ChemistryNiederrhein Univeristy of Applied Sciences Adlerstr. 1 D-47798 Krefeld Germany
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Chen SG, Yang J, Jia YG, Lu B, Ren L. TiO 2 and PEEK Reinforced 3D Printing PMMA Composite Resin for Dental Denture Base Applications. NANOMATERIALS 2019; 9:nano9071049. [PMID: 31336607 PMCID: PMC6669468 DOI: 10.3390/nano9071049] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/13/2019] [Accepted: 07/18/2019] [Indexed: 01/05/2023]
Abstract
The future of manufacturing applications in three-dimensional (3D) printing depends on the improvement and the development of materials suitable for 3D printing technology. This study aims to develop an applicable and convenient protocol for light-curing resin used in 3D industry, which could enhance antibacterial and mechanical properties of polymethyl methacrylate (PMMA) resin through the combination of nano-fillers of surface modified titanium dioxide (TiO2) and micro-fillers of polyetheretherketone (PEEK). PMMA-based composite resins with various additions of TiO2 and PEEK were prepared and submitted to characterizations including mechanical properties, distribution of the fillers (TiO2 or/and PEEK) on the fractured surface, cytotoxicity, antibacterial activity, and blood compatibility assessment. These results indicated that the reinforced composite resins of PMMA (TiO2-1%-PEEK-1%) possessed the most optimized properties compared to the other groups. In addition, we found the addition of 1% of TiO2 would be an effective amount to enhance both mechanical and antibacterial properties for PMMA composite resin. Furthermore, the model printed by PMMA (TiO2-1%-PEEK-1%) composite resin showed a smooth surface and a precise resolution, indicating this functional dental restoration material would be a suitable light-curing resin in 3D industry.
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Affiliation(s)
- Sheng-Gui Chen
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China
- National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, China
- School of Mechanical Engineering, Dongguan University of Technology, Dongguan 523808, China
| | - Junzhong Yang
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China
- National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, China
| | - Yong-Guang Jia
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China
- National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, China
| | - Bingheng Lu
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China
- National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, China
- School of Mechanical Engineering, Dongguan University of Technology, Dongguan 523808, China
| | - Li Ren
- School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China.
- National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, China.
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Liu H, Wang Y. Tertiary Amine and Tooth Mineral Hydroxyapatite Facilely Trigger Self-cure of 10-MDP Based Adhesives. INTERNATIONAL JOURNAL OF ADHESION & ADHESIVES 2019; 92:73-79. [PMID: 32042213 PMCID: PMC7009791 DOI: 10.1016/j.ijadhadh.2019.04.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The present work aims to investigate if a novel self-cure system, mediated by tertiary amine ethyl 4-(dimethylamino)-benzoate (4E) and tooth mineral hydroxyapatite (HAp), would trigger polymerization of model adhesives based on a popular self-etch monomer, 10- methacryloyloxydecyl dihydrogen phosphate (10-MDP). The effect of 4E and HAp contents on degree of conversion (DC), polymerization rate (Rp), and induction period (IP) was investigated. The occurrence of such self-cure phenomenon in adhesives that underwent prior inadequate light cure was also evaluated. Model self-etch adhesives were prepared by using a monomer mixture of 10-MDP with 2-hydroxyethyl methacrylate at1:1 wt. ratio. 4E (0.3-1.3 wt%), and HAp (0.5-2 wt%) were added to the mixture. Benzoylperoxide and N,N-dihydroxyethyl-p-toluidine were used as conventional chemical-cure system, and trimethylbenzoyl-diphenylphosphine oxide as light-curing photoinitiator. The polymerization processes and mechanical properties of model adhesives were evaluated by real time ATR/FT-IR and nanoindentation, respectively. The 4E- HAp system successfully triggered self-cure of 10-MDP based model adhesives. DC, Rp and IP were apparently affected by both 4E and HAp contents. DC of self-cure of the model adhesives was much higher than that of the conventional chemical-cure system. 4E-HAp initiated self-cure further boosted DC to ~100% regardless of prior light exposure, and significantly improved elastic modulus and hardness, thus provided a novel polymerization method to effectively salvage curing of the adhesives after inadequate light-cure.
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Affiliation(s)
- Hang Liu
- Department of Oral and Craniofacial Sciences, University of Missouri -Kansas City School of Dentistry, Kansas City, MO 64108, USA
| | - Yong Wang
- Department of Oral and Craniofacial Sciences, University of Missouri -Kansas City School of Dentistry, Kansas City, MO 64108, USA
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Giannini M, André CB, Gobbo VC, Rueggeberg FA. Accuracy of Irradiance and Power of Light-Curing Units Measured With Handheld or Laboratory Grade Radiometers. Braz Dent J 2019; 30:397-403. [DOI: 10.1590/0103-6440201902430] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/24/2019] [Indexed: 01/29/2023] Open
Abstract
Abstract This study measured and compared exitance irradiance and power of 4 commercial dental light-curing units (LCU) (Elipar S10, Elipar DeepCure-S, Corded VALO and Bluephase Style) using different types of radiometers. The devices used to analyze the LCU were classified as either handheld analog (Henry Schein, Spring, Demetron 100A, Demetron 100B and Demetron 200), handheld digital (Bluephase 1, Bluephase II, Coltolux, CureRite and Hilux), or laboratory instruments (Thermopile and Integrating Sphere). The laboratory instruments and the Bluephase II radiometer were also used to measure the LCU’s power (mW). The LCU’s were activated for 20 s (n=5). Data were analyzed using Kruskal-Wallis and Student-Newman-Keuls multiple comparison test (a=0.05). Among the LCU, the laboratory instruments presented different irradiance values, except for Corded VALO. The Coltolux and Hilux radiometers measured greater irradiance values compared to the laboratory instruments for the four LCUs tested. Within a given LCU, handheld analog units measured lower irradiance values, compared to handheld digital and laboratory instruments, except using the Spring radiometer for the Elipar S10 LCU. None of the handheld radiometers were able to measure similar irradiance values compared to laboratory instruments, except for Elipar S10 when comparing Bluephase 1 and Thermopile. Regarding power measurement, Bluephase II always presented the lowest values compared to the laboratory instruments. These findings suggest that the handheld radiometers utilized by practitioners (analog or digital) exhibit a wide range of irradiance values and may show lower outcomes compared to laboratory based instruments.
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de Oliveira DCRS, Rocha MG, Correr AB, Ferracane JL, Sinhoreti MAC. Effect of Beam Profiles From Different Light Emission Tip Types of Multiwave Light-emitting Diodes on the Curing Profile of Resin-based Composites. Oper Dent 2019; 44:365-378. [DOI: 10.2341/16-242] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Light activation is an important clinical step for achieving success in restorative procedures. This study evaluated the influence of beam profile from different light emission tip types of multiwave light-emitting diodes (LEDs) on the curing profile of resin-based composites. Experimental composites were produced containing either camphorquinone (CQ) or diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as a photoinitiator. Multiwave LEDs with either a bundle light guide tip (Bluephase G2, Ivoclar Vivadent) or a microlens tip (VALO Cordless, Ultradent) were characterized using a beam profiler. Block-shaped samples (5×5×3 mm depth) of the two composites were cured in a custom-designed mold with the multiwave LEDs positioned to compare the regions exposed to the 420-495 nm (blue) and 380-420 nm (violet) emittances. To map the curing profile, the degree of conversion (DC) of longitudinal thin cross sections from each block was evaluated using transmission FT-NIR. Radiant exposure transmitted through the composites during curing was evaluated at different thicknesses. Data were analyzed using analysis of variance and Tukey test (α=0.05; β=0.2). The results indicated that there were differences in the beam profile and the overall radiant exposures transmitted through the composites using each multiwave LED (p<0.01, df=1 F=73.18). However, there were no differences in the curing profiles provided by the two multiwave LEDs (p=0.89, df=12 F=0.52), and similar effects were found according to the different LED emittance regions (p=0.09, df=5, F=2.11). When considering up to 1 mm in depth, no differences in the DC were found between the composites containing either photoinitiators. Starting at 2 mm in depth, the composite containing TPO showed a decrease in DC in the 420-495 nm emittance region, while the composite containing CQ showed a similar decrease in cure efficiency only at 3-mm depth under both 380-420 nm and 420-495 nm emittance regions. Thus, despite the fact that the nonuniform light beam emitted from the two multiwave LEDs was visually distinctly different when delivering 24 J/cm2, this difference did not seem to affect the curing profile of the composites. However, light transmission within 380-420 nm seems to be reduced with depth, directly affecting the curing profile of composites containing a photoinitiator with absorbance falling within this emission range.
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Affiliation(s)
- DCRS de Oliveira
- Dayane Carvalho Ramos Salles de Oliveira, Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
| | - MG Rocha
- Mateus Garcia Rocha, Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
| | - AB Correr
- Américo Bortolazzo Correr, Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
| | - JL Ferracane
- Jack Liborio Ferracane, Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR, USA
| | - MAC Sinhoreti
- Mario Alexandre Coelho Sinhoreti, Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
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Spajic J, Par M, Milat O, Demoli N, Bjelovucic R, Prskalo K. Effects of Curing Modes on the Microhardness of Resin-modified Glass Ionomer Cements. Acta Stomatol Croat 2019; 53:37-46. [PMID: 31118531 PMCID: PMC6508928 DOI: 10.15644/asc53/1/4] [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] [Indexed: 11/30/2022] Open
Abstract
Objective This study evaluated the effects of curing modes on surface microhardness of visible light-cured resin-modified glass ionomer cements (VLC RMGIC) and a giomer after different storage periods in comparison to auto-cured resin-modified glass ionomer cements (AC RMGIC). Materials and Methods The following materials were used: VLC RMIC: Fuji II LC Improved, Photac Fil Quick Aplicap, AC RMGIC: Fuji Plus, Fuji VIII and Giomer: Beautifil II. The measurements of microhardness were performed using a Vickers test (100 g loads were applied for 10 s) in the following time intervals: immediately after the recommended cure and after 1, 7 and 14 days of immersion in distilled water. Five samples (d=4 mm, h=2 mm) were prepared for each combination of curing mode and tested material. Results After 14 days, an improvement of microhardness was evident in all tested materials. The full factorial ANOVA identified a highly significant (p<0.001) effect of the factors “material”, “time” and “curing mode (“low”, “soft“, „high”) for the light-cured materials Beautifil II, Fuji II LC and Photac Fil Quick. There was a statistically significant difference in the microhardness between different material types (Beautifil II˃Fuji II LC˃Photac Fil Quick˃Fuji Plus˃Fuji VIII) and curing modes (low ˂soft ˂high). Conclusions Material type had the greatest impact on microhardness, followed by the factor of time, while curing modes showed a considerably smaller influence on microhardness of the light-cured materials.
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Affiliation(s)
| | - Matej Par
- Department of Endodontics and Restorative Dental Medicine School of Dental Medicine University of Zagreb, Gundulićeva 5, Zagreb
| | | | | | | | - Katica Prskalo
- Department of Endodontics and Restorative Dental Medicine School of Dental Medicine University of Zagreb, Gundulićeva 5, Zagreb
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79
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Runnacles P, Arrais CAG, Maucoski C, Coelho U, De Goes MF, Rueggeberg FA. Comparison of in vivo and in vitro models to evaluate pulp temperature rise during exposure to a Polywave® LED light curing unit. J Appl Oral Sci 2019; 27:e20180480. [PMID: 31116279 PMCID: PMC6534370 DOI: 10.1590/1678-7757-2018-0480] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/31/2018] [Accepted: 11/28/2018] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES To measure and compare in vivo and in vitro pulp temperature (PT) increase (ΔTEMP) over baseline, physiologic temperature using the same intact upper premolars exposed to the same Polywave® LED curing light. METHODOLOGY After local Ethics Committee approval (#255,945), local anesthesia, rubber dam isolation, small occlusal preparations/minute pulp exposure (n=15) were performed in teeth requiring extraction for orthodontic reasons. A sterile probe of a temperature measurement system (Temperature Data Acquisition, Physitemp) was placed within the pulp chamber and the buccal surface was sequentially exposed to a LED LCU (Bluephase 20i, Ivoclar Vivadent) using the following exposure modes: 10-s low or high, 5-s Turbo, and 60-s high. Afterwards, the teeth were extracted and K-type thermocouples were placed within the pulp chamber through the original access. The teeth were attached to an assembly simulating the in vivo environment, being similarly exposed while real-time temperature (°C) was recorded. ΔTEMP values and time for temperature to reach maximum (ΔTIME) were subjected to two-way ANOVA and Bonferroni's post-hoc tests (pre-set alpha 0.05). RESULTS Higher ΔTEMP was observed in vitro than in vivo. No significant difference in ΔTIME was observed between test conditions. A significant, positive relationship was observed between radiant exposure and ΔTEMP for both conditions (in vivo: r2=0.917; p<0.001; in vitro: r2=0.919; p<0.001). CONCLUSION Although the in vitro model overestimated in vivo PT increase, in vitro PT rise was close to in vivo values for clinically relevant exposure modes.
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Affiliation(s)
- Patricio Runnacles
- Universidade Estadual de Ponta Grossa, Departamento de Odontologia Restauradora, Ponta Grossa, Paraná, Brasil
| | - Cesar Augusto Galvão Arrais
- Universidade Estadual de Ponta Grossa, Departamento de Odontologia Restauradora, Ponta Grossa, Paraná, Brasil
| | - Cristiane Maucoski
- Universidade Estadual de Ponta Grossa, Departamento de Odontologia Restauradora, Ponta Grossa, Paraná, Brasil
| | - Ulisses Coelho
- Universidade Estadual de Ponta Grossa, Departamento de Odontologia Restauradora, Ponta Grossa, Paraná, Brasil
| | - Mario Fernando De Goes
- Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba, Departamento de Materiais Dentários, Piracicaba, São Paulo, Brasil
| | - Frederick Allen Rueggeberg
- Augusta University, Dental College of Georgia, Department of Restorative Sciences, Dental Materials Section, Augusta, Georgia, USA
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80
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Al-Zain AO, Eckert GJ, Platt JA. The Influence of Distance on Radiant Exposure and Degree of Conversion Using Different Light-Emitting-Diode Curing Units. Oper Dent 2019; 44:E133-E144. [DOI: 10.2341/18-004-l] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Objectives:
To investigate the influence of curing distance on the degree of conversion (DC) of a resin-based composite (RBC) when similar radiant exposure was achieved using six different light-curing units (LCUs) and to explore the correlation among irradiance, radiant exposure, and DC.
Methods and Materials:
A managing accurate resin curing-resin calibrator system was used to collect irradiance data for both top and bottom specimen surfaces with a curing distance of 2 mm and 8 mm while targeting a consistent top surface radiant exposure. Square nanohybrid-dual-photoinitiator RBC specimens (5 × 5 × 2 mm) were cured at each distance (n=6/LCU/distance). Irradiance and DC (micro-Raman spectroscopy) were determined for the top and bottom surfaces. The effect of distance and LCU on irradiance, radiant exposure, and DC as well as their linear associations were analyzed using analysis of variance and Pearson correlation coefficients, respectively (α=0.05).
Results:
While maintaining a similar radiant exposure, each LCU exhibited distinctive patterns in decreased irradiance and increased curing time. No significant differences in DC values (63.21%-70.28%) were observed between the 2- and 8-mm distances, except for a multiple-emission peak LCU. Significant differences in DC were detected among the LCUs. As expected, irradiance and radiant exposure were significantly lower on the bottom surfaces. However, a strong correlation between irradiance and radiant exposure did not necessarily result in a strong correlation with DC.
Conclusions:
The RBC exhibited DC values >63% when the top surface radiant exposure was maintained, although the same values were not reached for all lights. A moderate-strong correlation existed among irradiance, radiant exposure, and DC.
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Affiliation(s)
- AO Al-Zain
- Afnan O Al-Zain, BDS, MSD, PhD, King Abdulaziz University, Faculty of Dentistry, Restorative Dentistry Department, Jeddah, Saudi Arabia
| | - GJ Eckert
- George J Eckert, MS, Indiana University School of Medicine, Division of Biostatistics, Indianapolis, IN, USA
| | - JA Platt
- Jeffrey A Platt, DDS, MS, Indiana University, Department of Biomedical and Applied Sciences, Indianapolis, IN, USA
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81
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Sarmiento-Cornejo J, Mackenney-Palamara M. Evaluation of intensity standards of tungsten-halogen and led curing units. JOURNAL OF ORAL RESEARCH 2019. [DOI: 10.17126/joralres.2019.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Current evidence indicates that the minimum light intensity of photo curing units required to polymerize in a reliable way a composite resin, in increments of 2mm, is 300mW/cm2. The recent introduction of new generations of composite resin materials for large volume increments, partially contrasts with ISO 4049 (2009), calling for the use of light intensity of 1,000mW/cm2. Therefore, it is considered relevant to carry out periodic measurements of the emission intensity of light-curing units of clinical use. The aim of this study was to test the intensity [mW/cm2] of a representative sample of tungsten-halogen and LED photopolymerization units used in private and public health service in different areas of the Valparaíso Region in Chile. This was achieved through the use of dental radiometers, without considering the variables of intensity modification over time (either spontaneously, by undesirable inherent characteristics of the device, or by programs of intensity modification in time), or the density of accumulated power needed. This in vitro diagnostic test, evaluated a sample of 507 units, 107 halogen and 400 LED, for a period of around one month, using two radiometers as measuring instruments. For LED units the Bluephase Meter® radiometer, from Ivoclar-VivadentTM was used, and for halogen units we used the Coltolux® from ColténeTM. As a result, 85% of the LED and halogen units achieved the minimum requirements of intensity needed for the polymerization of conventional dental biomaterials. However, only 25% from the tested units achieved a power density of 1,000mW/cm2.
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82
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Shim JS, Lee SY, Song SY, Jha N, Ryu JJ. Polymerization efficiency of dental dual-cured resin cement light-cured at various times after the initiation of chemical activation. INT J POLYM MATER PO 2019. [DOI: 10.1080/00914037.2019.1596912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Ji Suk Shim
- Department of Prosthodontics, Korea University Ansan Hospital, Republic of Korea
| | - Soo Young Lee
- Department of Medicine, Korea University Graduate School, Republic of Korea
| | - So-Yeon Song
- Department of Biomedical Science, Graduate School of Korea University, Republic of Korea
| | - Nayansi Jha
- Department of Medicine, Korea University Graduate School, Republic of Korea
| | - Jae Jun Ryu
- Department of Prosthodontics, Korea University Anam Hospital, Seoul, Republic of Korea
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83
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Effect of indirect restorative material and thickness on light transmission at different wavelengths. J Prosthodont Res 2019; 63:232-238. [DOI: 10.1016/j.jpor.2018.12.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 11/22/2018] [Accepted: 12/06/2018] [Indexed: 11/18/2022]
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84
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The effect of monowave and polywave light-polymerization units on the adhesion of resin cements to zirconia. J Prosthet Dent 2019; 121:549.e1-549.e7. [DOI: 10.1016/j.prosdent.2018.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 12/05/2018] [Accepted: 12/05/2018] [Indexed: 11/22/2022]
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85
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Najafi H, Akbari B, Najafi F, Shahabi S, Abrishamkar A, Moztarzadeh F, Yazdanpanah A. Characterization of the physical–mechanical properties of dental resin composites reinforced with novel micro-nano hybrid silica particles: An optimization study. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2019. [DOI: 10.1080/10601325.2018.1526040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Hamed Najafi
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Babak Akbari
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Farhood Najafi
- Department of Resin and Additives, Institute for Color Science and Technology, Tehran, Iran
| | - Sima Shahabi
- Laser Research Center of Dentistry, Tehran University of Medical Science, Tehran, Iran
| | | | - Fathollah Moztarzadeh
- Biomaterials Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran, Iran
| | - Abolfazl Yazdanpanah
- Biomaterials Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran, Iran
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86
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Al-Zain AO, Eckert GJ, Lukic H, Megremis S, Platt JA. Polymerization pattern characterization within a resin-based composite cured using different curing units at two distances. Clin Oral Investig 2019; 23:3995-4010. [PMID: 30737620 DOI: 10.1007/s00784-019-02831-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 01/25/2019] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To investigate the relationship of the irradiance-beam-profile areas from six different light-curing units (LCUs) with the degree of conversion (DC), microhardness (KH), and cross-link density (CLD) throughout a resin-based composite (RBC) cured at two clinically relevant distances, and to explore the correlations among them. MATERIALS AND METHODS A mapping approach was used to measure DC using micro-Raman spectroscopy, KH using a Knoop indentor on a hardness tester, and %KH reduction after ethanol exposure, as an indicator for CLD within a nano-hybrid RBC increment (n = 3) at various depths. These sample composites were cured from two distances while maintaining the radiant exposure, using six different light-curing units: one quartz-tungsten-halogen; two single and three multiple-emission-peak light-emitting-diode units. Irradiance beam profiles were generated for each LCU at both distances, and localized irradiance values were calculated. Points across each depth were analyzed using repeated measures ANOVA. Correlations across multiple specimen locations and associations between beam uniformity corresponding with polymerization measurements were calculated using linear mixed models and Pearson correlation coefficients. RESULTS Significant non-uniform polymerization patterns occurred within the specimens at various locations and depths. At 2-mm curing distance, the localized DC = 52.7-76.8%, KH = 39.0-66.7 kg/mm2, and %KH reduction = 26.7-57.9%. At 8-mm curing distance, the localized DC = 50.4-78.6%, KH = 40.3-73.7 kg/mm2, and %KH reduction = 28.2-56.8%. The localized irradiance values were weakly correlated with the corresponding DC, KH, and %KH reduction, with only a few significant correlations (p < 0.05). CONCLUSIONS Although significant differences were observed at each depth within the specimens, the localized irradiance values for all LCUs did not reflect the polymerization pattern and did not seem to have a major influence on polymerization patterns within the RBC, regardless of the curing distance. CLINICAL RELEVANCE Commonly used LCUs do not produce uniform polymerization regardless of the curing distance, which may contribute to the risk of RBC fracture.
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Affiliation(s)
- Afnan O Al-Zain
- Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, P.O. Box: 80209, Jeddah, 21589, Saudi Arabia.
| | - George J Eckert
- Department of Biostatistics, Indiana University School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Henry Lukic
- Research and Standards, American Dental Association Science Institute, Chicago, IL, USA
| | - Spiro Megremis
- Research and Standards, American Dental Association Science Institute, Chicago, IL, USA
| | - Jeffrey A Platt
- Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
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87
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Malarvizhi D, Karthick A, Gold Pearlin Mary NS, Venkatesh A. Shrinkage in composites: An enigma. J Int Oral Health 2019. [DOI: 10.4103/jioh.jioh_36_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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88
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Cadenaro M, Maravic T, Comba A, Mazzoni A, Fanfoni L, Hilton T, Ferracane J, Breschi L. The role of polymerization in adhesive dentistry. Dent Mater 2019; 35:e1-e22. [DOI: 10.1016/j.dental.2018.11.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 10/27/2022]
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89
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Daokar S, Hadole P. Light-curing unit (devices). INTERNATIONAL JOURNAL OF ORTHODONTIC REHABILITATION 2019. [DOI: 10.4103/ijor.ijor_1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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90
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Sahadi BO, Price RB, André CB, Sebold M, Bermejo GN, Palma-Dibb RG, Faraoni JJ, Soares CJ, Giannini M. Multiple-peak and single-peak dental curing lights comparison on the wear resistance of bulk-fill composites. Braz Oral Res 2018; 32:e122. [DOI: 10.1590/1807-3107bor-2018.vol32.0122] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 10/24/2018] [Indexed: 11/21/2022] Open
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91
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De Santis R, Russo T, Gloria A. An analysis on the potential of diode-pumped solid-state lasers for dental materials. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 92:862-867. [PMID: 30184815 DOI: 10.1016/j.msec.2018.07.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 07/09/2018] [Accepted: 07/20/2018] [Indexed: 11/30/2022]
Abstract
Material structure-property relationship is strongly related to the employed process technology. Over the past years, laser processing of engineering materials has been proposed in many fields and different uses for diode lasers have been found in dentistry. In this contest, the potential of GaN- and InGaN-based laser diodes to cure dental materials was analysed. Two wavelengths of 405 nm and 445 nm were used as heat or light sources for warm condensation of gutta-percha, light transmission in dental posts and brackets or light curing of dental composites. Additive manufacturing approach was considered to fabricate 3D root analogues, suitable supports, positioning systems and moulds for optical measurements. A three-axis CAD/CAM system was implemented for positioning and aligning the laser beam. The ability of diode-pumped solid-state lasers to cure dental materials or to transmit light was compared to that of a traditional instrument. Temperature profile at the apex of an additive manufactured root canal sealed with gutta-percha, light transmission through translucent quartz fiber post or through aesthetic ceramic bracket, bending properties and morphological features of light cured dental composites (Gradia Direct - GC Corporation and Venus Diamond - Heraeus Kulzer) were measured. Results showed a very high potential of diode-pumped solid-state lasers to be used in endodontics, orthodontics and restorative dentistry.
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Affiliation(s)
- Roberto De Santis
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54 - Pad. 20 Mostra d'Oltremare, 80125 Naples, Italy
| | - Teresa Russo
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54 - Pad. 20 Mostra d'Oltremare, 80125 Naples, Italy
| | - Antonio Gloria
- Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, V.le J.F. Kennedy 54 - Pad. 20 Mostra d'Oltremare, 80125 Naples, Italy.
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92
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Lima RBW, Troconis CCM, Moreno MBP, Murillo-Gómez F, De Goes MF. Depth of cure of bulk fill resin composites: A systematic review. J ESTHET RESTOR DENT 2018; 30:492-501. [PMID: 30375146 DOI: 10.1111/jerd.12394] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/13/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate scientific evidence regarding depth of cure of bulk-fill resin composites (BFRCs) and related factors. MATERIAL AND METHODS PubMed/Medline, Embase, Scopus, and ISI Web of Science databases were accessed from October 2016 to May 2017. Investigations published in English language, assessing depth of cure of BFRCs by microhardness test and/or degree of conversion (DC) were included. Studies using exclusively ISO 4049, employing specimens deepness less than 4 mm, as well as those not reporting exposure time and/or irradiance from light curing units (LCUs) were excluded. RESULTS In total, 742 studies were found from which 33 were included. From 21 studies evaluating BFRCs microhardness, 10 showed acceptable bottom/top ratios (≥0.8) for all tested materials. However, material-dependent results and non-satisfactory bottom/top microhardness ratios (<0.8) were reported in 9 and 2 investigations, respectively. From 19 studies that assessed DC, 11 showed acceptable results (≥50%) for all tested BFRCs, while 8 studies reported material-dependent outcomes. Overall, irradiance from LCUs ranged from 650 to 1330 mW/cm2 and exposure time from 5 to 60 seconds. Favorable depth of cure results were observed with the use of LCUs emitting irradiance ≥1000 mW/cm2 and exposure times ≥20 seconds. CONCLUSIONS High depth of cure rates by BFRCs, depends on some factors as material, irradiance and exposure time. Polywave LCUs were useful but not essential on polymerizing alternative photoinitiator-containing BFRC. CLINICAL SIGNIFICANCE LED curing devices (polywave or monowave) displaying an irradiance ≥1000 mW/cm2 and 20 seconds of exposure time are imperative to accomplish successful polymerization of most BFRCs.
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Affiliation(s)
- Renally Bezerra Wanderley Lima
- Department of Restorative Dentistry (Dental Materials Area), Piracicaba Dental School, University of Campinas - UNICAMP, Avenida Limeira, Campinas, São Paulo, 13414-903, Brazil
| | - Cristhian Camilo Madrid Troconis
- Department of Restorative Dentistry (Dental Materials Area), Piracicaba Dental School, University of Campinas - UNICAMP, Avenida Limeira, Campinas, São Paulo, 13414-903, Brazil
| | - Marina Barrêto Pereira Moreno
- Department of Restorative Dentistry (Dental Materials Area), Piracicaba Dental School, University of Campinas - UNICAMP, Avenida Limeira, Campinas, São Paulo, 13414-903, Brazil
| | - Fabián Murillo-Gómez
- Department of Restorative Dentistry (Dental Materials Area), Piracicaba Dental School, University of Campinas - UNICAMP, Avenida Limeira, Campinas, São Paulo, 13414-903, Brazil.,Department of Restorative Dentistry, School of Dentistry, University of Costa Rica-UCR, Rodrigo Facio "Campus,", San José, Costa Rica
| | - Mario Fernando De Goes
- Department of Restorative Dentistry (Dental Materials Area), Piracicaba Dental School, University of Campinas - UNICAMP, Avenida Limeira, Campinas, São Paulo, 13414-903, Brazil
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93
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Par M, Repusic I, Skenderovic H, Sever EK, Marovic D, Tarle Z. Real-time Light Transmittance Monitoring for Determining Polymerization Completeness of Conventional and Bulk Fill Dental Composites. Oper Dent 2018; 43:E19-E31. [PMID: 29284096 DOI: 10.2341/17-041-l] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES To monitor the real-time changes in light transmittance during composite curing and to use transmittance data to determine the curing times required for a complete polymerization. METHODS Three conventional and three bulk fill composites were cured with two light-emitting diode curing units at layer thicknesses of 2 mm and 4 mm. The real-time light transmittance data were collected by a UV-Vis spectrometer in the wavelength range of 350-550 nm, plotted against time (t) and fitted to an exponential function f(t), whose first derivative ΔT(t) = df(t)/dt represented the rate of transmittance change. As the changing transmittance reflects structural changes that occur during polymerization, ΔT(t) > 0 was considered to indicate an ongoing polymerization, whereas ΔT(t) values approaching zero suggested a complete polymerization. This principle was used to determine times required for a complete polymerization (tcomplete) for each material/thickness/curing unit combination. RESULTS Light transmittance was significantly influenced by the material type, sample thickness, and curing unit, amounting to 2.9%-27.0% for the bulk fill and 0.7%-16.7% for the conventional composites. The values of tcomplete amounted to 15.3-23.3 seconds for the bulk fill composites at 2 mm, 20.2-33.3 seconds for the conventional composites at 2 mm, 26.9-42.1 seconds for the bulk fill composites at 4 mm, and 40.1-59.8 seconds for the conventional composites at 4 mm. Additionally, an exponential relationship was discovered between the light transmittance and tcomplete. CONCLUSIONS Some of the tcomplete values considerably exceeded the curing times recommended by the manufacturers.
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94
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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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95
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Examining the Effect of Radiant Exposure on Commercial Photopolimerizable Dental Resin Composites. Dent J (Basel) 2018; 6:dj6040055. [PMID: 30301279 PMCID: PMC6313541 DOI: 10.3390/dj6040055] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 10/04/2018] [Indexed: 11/17/2022] Open
Abstract
The objective of this study was to evaluate the effect of radiant exposure on the chemical and physical properties of four commercial dental resin composites. The four dental resin composites used were Kalore, Admira, Tetric N-Ceram Bulk Fill, and Filtek Z350 XT. The composites were subjected to three curing protocols: 1000 mW/cm2 for 5 s, 1000 mW/cm2 for 10 s, and 400 mW/cm2 for 25 s. The flexural strength, elastic modulus, water sorption, water solubility, degree of conversion, and polymerization shrinkage were evaluated. The results were analyzed by means of ANOVA and Tukey tests. For Admira and Kalore, significant differences between light exposure protocols were observed for the elastic modulus (p < 0.001), which was higher when a higher amount of radiant exposure was used. For Filtek Z350, differences were only observed for the degree of conversion (p < 0.001), and a higher amount of radiant exposure allowed us to obtain higher values. The Tetric N-Ceram Bulk Fill analysis showed significant differences for the elastic modulus and water sorption (p < 0.001), and specimens that had been subject to a radiant exposure of 10 J/cm2 showed a higher elastic modulus. In most cases, the physical and mechanical properties analyzed were not affected by different radiant exposure values. Other resin-based composite (RBC) characteristics seem to have a greater influence on material properties.
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Soares CJ, Rodrigues MDP, Oliveira LRS, Braga SSL, Barcelos LM, Silva GRD, Giannini M, Price RB. An Evaluation of the Light Output from 22 Contemporary Light Curing Units. Braz Dent J 2018; 28:362-371. [PMID: 29297558 DOI: 10.1590/0103-6440201601466] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/14/2017] [Indexed: 11/21/2022] Open
Abstract
This study measured the radiant power (mW), irradiance (mW/cm2) and emission spectra (mW/cm2/nm) of 22 new, or almost new, light curing units (LCUs): - Alt Lux II, BioLux Standard, Bluephase G2, Curing Light XL 3000, Demetron LC, DX Turbo LED 1200, EC450, EC500, Emitter C, Emitter D, KON-LUX, LED 3M ESPE, Led Lux II, Optilight Color, Optilight Max, Optilux 501, Poly Wireless, Radii cal, Radii plus, TL-01, VALO Cordless. These LCUs were either monowave or multiple peak light emitting diode (LED) units or quartz-tungsten-halogen LCUs used in anterior and posterior teeth. The radiant power emitted by the LCUs was measured by a laboratory grade laser power meter. The tip area (cm²) of the LCUs was measured and used to calculate the irradiance from the measured radiant power source. The MARC-Patient Simulator (MARC-PS) with a laboratory grade spectrometer (USB4000, Ocean Optics) was used to measure the irradiance and emission spectrum from each LCU three times at the sensor located on the facial of the maxillary central incisors and then separately at the occlusal of a maxillary second molar. The minimum acceptable irradiance level was set as 500 mW/cm2. Irradiance data was analyzed using two-way ANOVA and the radiant power data was analyzed by one-way ANOVA followed by Tukey test (a=0.05). In general, the irradiance was reduced at the molar tooth for most LCUs. Only the Valo, Bluephase G2 and Radii Plus delivered an irradiance similar to the anterior and posterior sensors greater than 500 mW/cm2. KON-LUX, Altlux II, Biolux Standard, TL-01, Optilux 501, DX Turbo LED 1200 LCUs delivered lower irradiance values than the recommended one used in molar region, KON-LUX and Altlux II LCUs used at the maxillary incisors. Bluephase G2 and Optilight Max delivered the highest radiant power and KON-LUX, Altlux II and Biolux Standard delivered the lowest power. The emission spectrum from the various monowave LED LCUs varied greatly. The multi-peak LCUs delivered similar emission spectra to both sensors.
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Affiliation(s)
- Carlos José Soares
- Department of Operative Dentistry, UFU - Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
| | | | - Laís Rani Sales Oliveira
- Department of Operative Dentistry, UFU - Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
| | | | - Luciana Mendes Barcelos
- Department of Operative Dentistry, UFU - Universidade Federal de Uberlândia, Uberlândia, MG, Brazil
| | | | - Marcelo Giannini
- Department of Restorative Dentistry, Piracicaba Dental School, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil
| | - Richard Bengt Price
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
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Alkhudhairy FI. The effects of irradiance and exposure time on the surface roughness of bulk-fill composite resin restorative materials. Saudi Med J 2018; 39:197-202. [PMID: 29436570 PMCID: PMC5885098 DOI: 10.15537/smj.2018.2.21440] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVES To evaluate the surface roughness of 4 different bulk-fill resin-based composites cured using different irradiance levels. Methods: This in vitro study was performed in February 2017 to August 2017 at the College of Dentistry, King Saud University. Twenty-four specimens were prepared from each of the bulk-fill materials [Tetric N-Ceram (TNC), SonicFill (SF), Smart Dentin Replacement (SDR), and Filtek Bulk-Fill (FB)] using a brass metal mold, resulting in a total of 96 specimens, cured using a Bluephase N light curing unit. Half of the total number of specimens (N=48) were cured using high-power irradiance (1200 mW/cm2) for 20 seconds, while the remaining half (N=48) were cured using low power irradiance (650 mW/cm2) for 40 seconds. After 24 hours, baseline surface roughness of each specimen was analyzed using a profilometer, then polished using Sof-lex abrasive disks, and the surface roughness of all groups was assessed. Results: Post-polished SonicFill cured at high irradiance had the highest mean surface roughness (0.23±0.03), whereas pre-polished Smart Dentin Replacement (0.11±0.01) and SonicFill (0.11±0.02) cured at low irradiance had the lowest mean surface roughness. Conclusion: High curing irradiance (1,200 mW/cm2) had no positive influence on the surface roughness of Filtek Bulk Fill and Tetric N-Ceram bulk-fill RBCs compared with lower curing irradiance (650 mW/cm2). However, the difference of curing irradiance significantly affected the surface roughness in SDR and sonic fill RBCs.
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Affiliation(s)
- Fahad I Alkhudhairy
- Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia. E-mail.
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AlShaafi MM, AlQussier A, AlQahtani MQ, Price RB. Effect of Mold Type and Diameter on the Depth of Cure of Three Resin-Based Composites. Oper Dent 2018; 43:520-529. [DOI: 10.2341/17-122-l] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Objective:
To evaluate the effects of different mold materials, their diameters, and light-curing units on the mechanical properties of three resin-based composites (RBC).
Methods and Materials:
A conventional nano-filled resin composite (Filtek Supreme Ultra, 3M Oral Care, St Paul, MN, USA) and two bulk-fill composites materials, Tetric Evoceram Bulk fill (Ivoclar Vivadent, Schaan, Liechtenstein) and Aura Bulk Fill (SDI, Bayswater, VIC, Australia), were tested. A total of 240 specimens were fabricated using metal or white semitransparent Delrin molds that were 4 or 10 mm in diameter. The RBCs were light cured for 40 seconds on the high-power setting of either a monowave (DeepCure-S, 3M Oral Care) or polywave (Bluephase G2, Ivoclar Vivadent) light-emitting diode (LED) curing unit. The depth of cure was determined using a scraping test, according to the 2009 ISO 4049 test method. Data were analyzed using multivariate analysis of variance followed by Tukey multiple comparison test (p<0.05).
Results:
In general, when used for 40 seconds, both LED curing lights achieved the same depth of cure (p=0.157). However, the mold material and its diameter had a significant effect on the depth of cure of all three RBCs (p<0.0001).
Conclusion:
Curing with either the polywave or monowave LED curing light resulted in the same depth of cure in the composites. The greatest depth of cure was always achieved using the 10-mm-diameter Delrin mold. Of the three RBCs tested, both Tetric Bulk Fill and Aura achieved a 4-mm depth of cure when tested in the 10-mm-diameter metal mold. Tetric Bulk Fill was the most transparent and had the greatest depth of cure, and the conventional composite had the least depth of cure. Very little violet (<420 nm) light penetrated through 6 mm of any of the RBCs.
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Affiliation(s)
- MM AlShaafi
- Maan M AlShaafi, BDS, MS, King Saud University, Restorative Dental Sciences, Riyadh, Saudi Arabia
| | - A AlQussier
- Anfal AlQussier, BDS, King Saud University, College of Dentistry, Restorative Dental Sciences, Riyadh, Saudi Arabia
| | - MQ AlQahtani
- Mohammed Q AlQahtani, BDS, MSD, King Saud University, College of Dentistry, Restorative Dental Sciences, Riyadh, Saudi Arabia
| | - RB Price
- Richard B Price, BDS, DDS, MS, PhD, FDS RCS (Edin), FRCD(C), Dalhousie University, Dental Clinical Sciences, Halifax, Canada
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Eshmawi YT, Al-Zain AO, Eckert GJ, Platt JA. Variation in composite degree of conversion and microflexural strength for different curing lights and surface locations. J Am Dent Assoc 2018; 149:893-902. [PMID: 30149887 DOI: 10.1016/j.adaj.2018.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 06/07/2018] [Accepted: 06/08/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND Lack of irradiance-beam profile uniformity across the emission area of light-curing units (LCUs) may result in suboptimal properties of composite restorations. The authors' objective for this study was to assess the variation in local cure of 1 composite at 3 different LCU emission area locations cured with 3 different LCUs by means of testing the degree of conversion (DC) and microflexural strength. METHODS The authors fabricated dual-photoinitiator composite specimens (n = 5), which were cured using either a quartz-tungsten-halogen, a multiple-emission peak, or a single-emission peak light-emitting diode LCU. The specimen's top surfaces received irradiation from either the center, 1.5 millimeters straight to the left of the center, or 1.5 mm straight to the right of the center of the LCU emission area. The authors measured irradiance and DC on top and bottom specimen surfaces using a spectrometer and attenuated total reflection-Fourier transform infrared spectroscopy, respectively. The authors performed micro 3-point bend tests using a universal mechanical testing machine. They used multifactorial analysis of variance (α = 0.05). RESULTS The irradiance ranged from 452 through 946 milliwatts per square centimeter, and DC ranged from 49.7% through 65.8% on top surfaces. Microflexural strength ranged from 313 through 458 megapascals. CONCLUSIONS The authors did not find correlations among the LCU irradiance-beam profile of the 3 emission area locations and the investigated material properties, although they found variations in the measured properties. PRACTICAL IMPLICATIONS The irradiance-beam profile from the different LCUs explored did not have a major influence on the DC and microflexural strength for the investigated composite.
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Almeida LF, Martins LP, Martins RP. Effects of reducing light-curing time of a high-power LED device on shear bond strength of brackets. J Orofac Orthop 2018; 79:352-358. [PMID: 30066016 DOI: 10.1007/s00056-018-0146-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 06/14/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE To assess the effects of reducing the curing time of a high-power light-emitting diode (LED) unit (Valo, Ultradent, South Jordan, UT, USA) on shear bond strength (SBS) of metal brackets and on the amount of adhesive remnant of two orthodontic composites. METHODS Eighty human premolars were divided into four groups (G1-4) according to curing time and composite: G1 (Transbond XT, 6 s), G2 (Opal Bond MV, 6 s), G3 (Transbond XT, 3 s), and G4 (Opal Bond MV, 3 s). Twenty-four hours after bonding, brackets were subject to a SBS test performed with a universal testing machine. Enamel surface was analyzed by SEM and the amount of adhesive remnant was assessed by the Image J software area calculation tool. Two-way analysis of variance was used for statistical analysis of SBS data, while Friedman and Mann-Whitney post hoc tests were used to analyze data on the amount of adhesive remnant. RESULTS Time and composite significantly affected SBS (p < 0.001). The 6 s curing showed a higher SBS value (21.56 MPa) in comparison to 3 s curing (15.79 MPa). Transbond XT composite showed a significantly higher SBS value (21.06 MPa) compared to Opal Bond MV (16.29 MPa). After the SBS test, Opal Bond MV showed a significantly greater amount of composite adhered to enamel (p < 0.001). CONCLUSION Reducing exposure time from 6 to 3 s significantly decreased mean values of SBS, even with the use of a high-power LED unit. Reduction in time did not affect the amount of adhesive remnant.
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Affiliation(s)
| | | | - Renato Parsekian Martins
- Department of Orthodontics, Universidade Estadual Paulista, Araraquara, Brazil. .,Private practice, Rua Carlos Gomes, 2158, 14801340, Araraquara, SP, Brazil.
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