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Maletin A, Knežević MJ, Koprivica DĐ, Veljović T, Puškar T, Milekić B, Ristić I. Dental Resin-Based Luting Materials-Review. Polymers (Basel) 2023; 15:4156. [PMID: 37896400 PMCID: PMC10610675 DOI: 10.3390/polym15204156] [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: 07/20/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
As cementation represents the last stage of the work involved in making various indirect restorations (metal ceramic crowns and bridges, full ceramic crowns and bridges, inlays, onlays, and fiber posts), its quality significantly contributes to the clinical success of the therapy performed. In the last two decades, the demand for ceramic indirect restorations in everyday dental practice has considerably increased primarily due to the growing significance of esthetics among patients, but also as a result of hypersensitivity reactions to dental alloys in some individuals. In this context, it is essential to ensure a permanent and reliable adhesive bond between the indirect restoration and the tooth structure, as this is the key to the success of aesthetic restorations. Resin-based luting materials benefit from excellent optical (aesthetic) and mechanical properties, as well as from providing a strong and durable adhesive bond between the restoration and the tooth. For this reason, resin cements are a reliable choice of material for cementing polycrystalline ceramic restorations. The current dental material market offers a wide range of resin cement with diverse and continually advancing properties. In response, we wish to note that the interest in the properties of resin-based cements among clinicians has existed for many years. Yet, despite extensive research on the subject and the resulting continued improvements in the quality of these materials, there is still no ideal resin-based cement on the market. The manuscript authors were guided by this fact when writing the article content, as the aim was to provide a concise overview of the composition, properties, and current trends, as well as some future guidelines for research in this field that would be beneficial for dental practitioners as well as the scientific community. It is extremely important to provide reliable and succinct information and guidelines for resin luting materials for dental dental practitioners.
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Affiliation(s)
- Aleksandra Maletin
- Faculty of Medicine, University of Novi Sad, 21000 Novi Sad, Serbia; (M.J.K.); (D.Đ.K.); (T.V.); (T.P.); (B.M.)
| | - Milica Jeremić Knežević
- Faculty of Medicine, University of Novi Sad, 21000 Novi Sad, Serbia; (M.J.K.); (D.Đ.K.); (T.V.); (T.P.); (B.M.)
| | - Daniela Đurović Koprivica
- Faculty of Medicine, University of Novi Sad, 21000 Novi Sad, Serbia; (M.J.K.); (D.Đ.K.); (T.V.); (T.P.); (B.M.)
| | - Tanja Veljović
- Faculty of Medicine, University of Novi Sad, 21000 Novi Sad, Serbia; (M.J.K.); (D.Đ.K.); (T.V.); (T.P.); (B.M.)
| | - Tatjana Puškar
- Faculty of Medicine, University of Novi Sad, 21000 Novi Sad, Serbia; (M.J.K.); (D.Đ.K.); (T.V.); (T.P.); (B.M.)
| | - Bojana Milekić
- Faculty of Medicine, University of Novi Sad, 21000 Novi Sad, Serbia; (M.J.K.); (D.Đ.K.); (T.V.); (T.P.); (B.M.)
| | - Ivan Ristić
- Faculty of Technology, University of Novi Sad, 21000 Novi Sad, Serbia;
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Lempel E, Szebeni D, Őri Z, Kiss T, Szalma J, Lovász BV, Kunsági-Máté S, Böddi K. The effect of high-irradiance rapid polymerization on degree of conversion, monomer elution, polymerization shrinkage and porosity of bulk-fill resin composites. Dent Mater 2023; 39:442-453. [PMID: 36918332 DOI: 10.1016/j.dental.2023.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 02/17/2023] [Accepted: 03/03/2023] [Indexed: 03/13/2023]
Abstract
OBJECTIVE The purpose was to compare the degree of conversion (DC), monomer elution (ME), polymerization shrinkage (PS) and porosity of two addition-fragmentation chain transfer (AFCT) modified resin-based composites (RBC) light-cured with rapid- (RP), turbo- (TP) or conventional polymerization (CP) settings. METHODS Cylindrical samples (6-mm wide, 4-mm thick) were prepared from Tetric PowerFill (TPF) and Filtek One Bulk (FOB). Four groups were established according to the polymerization settings: 3s-RP, 5s-TP, 10s-CP and 20s-CP. Samples in 1 mm thickness with 20s-CP settings served as controls. The DC at the top and bottom surfaces was measured with micro-Raman spectroscopy. ME was detected with high-performance liquid chromatography. PS and porosity were analyzed by micro-computed tomography. ANOVA and Tukey's post-hoc test, multivariate analysis and partial eta-squared statistics were used to analyze the data (p < 0.05). RESULTS FOB showed higher DC values (61.5-77.5 %) at the top compared to TPF (43.5-67.8 %). At the bottom TPF samples achieved higher DCs (39.9-58.5 %) than FOB (18.21-66.18 %). Extending the curing time increased DC (except the top of FOB) and decreased ME. BisGMA release was the highest among the detected monomers from both RBCs. The amount was three-fold more from TPF. The factor Material and Exposure significantly influenced DC and ME. PS (1.8-2.5 %) did not differ among the groups and RBCs except for the lowest value of TPF cured with the 3s_RP setting (p = 0.03). FOB showed 4.5-fold lower porosity (p < 0.001). Significantly higher pore volume was detected after polymerization in 3s_RP (p < 0.001). SIGNIFICANCE High-irradiance rapid 3-s curing of AFCT modified RBCs resulted in inferior results for some important material properties. A longer exposure time is recommended in a clinical situation.
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Affiliation(s)
- Edina Lempel
- Department of Restorative Dentistry and Periodontology, University of Pécs Medical School, Tüzér Street 1, Pécs 7623, Hungary.
| | - Donát Szebeni
- Department of Restorative Dentistry and Periodontology, University of Pécs Medical School, Tüzér Street 1, Pécs 7623, Hungary
| | - Zsuzsanna Őri
- János Szentágothai Research Center, Ifjúság Street 12, Pécs 7624, Hungary; Department of General and Physical Chemistry, University of Pécs, Ifjúság Street 6, Pécs 7624, Hungary
| | - Tamás Kiss
- János Szentágothai Research Center, Ifjúság Street 12, Pécs 7624, Hungary
| | - József Szalma
- Department of Oral and Maxillofacial Surgery, University of Pécs Medical School, Tüzér Street 1, Pécs 7623, Hungary
| | - Bálint Viktor Lovász
- Department of Oral and Maxillofacial Surgery, University of Pécs Medical School, Tüzér Street 1, Pécs 7623, Hungary
| | - Sándor Kunsági-Máté
- János Szentágothai Research Center, Ifjúság Street 12, Pécs 7624, Hungary; Department of Organic and Medicinal Chemistry, University of Pécs, Faculty of Pharmacy, Honvéd Street 1, Pécs 7624, Hungary
| | - Katalin Böddi
- Department of Biochemistry and Medical Chemistry, University of Pécs Medical School, Szigeti Street 12, Pécs 7624, Hungary
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Maucoski C, Price RB, Rocha MG, Roulet JF, Sullivan B. Ability of short exposures from laser and quad-wave curing lights to photo-cure bulk-fill resin-based composites. Dent Mater 2023; 39:275-292. [PMID: 36868892 DOI: 10.1016/j.dental.2023.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 01/10/2023] [Accepted: 01/25/2023] [Indexed: 03/05/2023]
Abstract
OBJECTIVE This study investigated the ability of a laser, and a 'quad-wave' LCU, to photo-cure paste and flowable bulk-fill resin-based composites (RBCs). METHODS Five LCUs and nine exposure conditions were used. The laser LCU (Monet) used for 1 s and 3 s, the quad-wave LCU (PinkWave) used for 3 s in the Boost and 20 s in the Standard modes, the the multi-peak LCU (Valo X) used for 5 s in the Xtra and 20 s in the Standard modes, were compared to the polywave PowerCure used in the 3 s mode and for 20 s in the Standard mode, and to the mono-peak SmartLite Pro used for 20 s. Two paste consistency bulk-fill RBCs: Filtek One Bulk Fill Shade A2 (3 M), Tetric PowerFill Shade IVA (Ivoclar Vivadent), and two flowable RBCs: Filtek Bulk Fill Flowable Shade A2 (3 M), Tetric PowerFlow Shade IVA (Ivoclar Vivadent) were photo-cured in 4-mm deep x 4-mm diameter metal molds. The light received by these specimens was measured using a spectrometer (Flame-T, Ocean Insight), and the radiant exposure delivered to the top surface of the RBCs was mapped. The immediate degree of conversion (DC) at the bottom, and the 24-hour Vickers Hardness (VH) at the top and bottom of the RBCs were measured and compared. RESULTS The irradiance received by the 4-mm diameter specimens ranged from 1035 mW/cm2 (SmartLite Pro) to 5303 mW/cm2 (Monet). The radiant exposures between 350 and 500 nm delivered to the top surface of the RBCs ranged from 5.3 J/cm2 (Monet in 1 s) to 26.4 J/cm2 (Valo X), although the PinkWave delivered 32.1 J/cm2 in 20 s 350 to 900 nm. All four RBCs achieved their maximum DC and VH values at the bottom when photo-cured for 20 s. The Monet used for 1 s and the PinkWave used for 3 s on the Boost setting delivered the lowest radiant exposures between 420 and 500 nm (5.3 J/cm2 and 3.5 J/cm2 respectively), and they produced the lowest DC and VH values. CONCLUSIONS Despite delivering a high irradiance, the short 1 or 3-s exposures delivered less energy to the RBC than 20-s exposures from LCUs that deliver> 1000 mW/cm2. There was an excellent linear correlation (r > 0.98) between the DC and the VH at the bottom. There was a logarithmic relationship between the DC and the radiant exposure (Pearson's r = 0.87-97) and between the VH and the radiant exposure (Pearson's r = 0.92-0.96) delivered in the 420-500 nm range.
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Affiliation(s)
- Cristiane Maucoski
- Department of Restorative Dentistry, State University of Ponta Grossa, Ponta Grossa, Parana, Brazil; Department of Dental Clinical Sciences, Dalhousie University, Faculty of Dentistry, Halifax, Nova Scotia, Canada
| | - Richard Bengt Price
- Department of Dental Clinical Sciences, Dalhousie University, Faculty of Dentistry, Halifax, Nova Scotia, Canada.
| | - Mateus Garcia Rocha
- Department of Restorative Dental Science, Center of Dental Biomaterials College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Jean-François Roulet
- Department of Restorative Dental Science, Center of Dental Biomaterials College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Braden Sullivan
- Department of Restorative Dentistry, State University of Ponta Grossa, Ponta Grossa, Parana, Brazil
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Labrie D, Price RB, Sullivan B, Salazar AM, Gautam D, Stansbury JW, Ferracane JL. Effect of thickness on the degree of conversion of two bulk-fill and one conventional posterior resin-based composites at high irradiance and high temporal resolution. J Mech Behav Biomed Mater 2022; 136:105489. [PMID: 36206689 DOI: 10.1016/j.jmbbm.2022.105489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This study: 1) measures the effect of sample thickness and high irradiance on the depth-dependent time delay before photopolymerization reaction onset; 2) determines if exposure reciprocity exists; 3) measures the conversion rate at four irradiance levels; 4) determines the time, t0, at which the maximum DC rate is reached for two bulk-fill and one conventional posterior resin-based composites (RBCs). METHODS Tetric PowerFill IVA shade (Ivoclar Vivadent) and Aura bulk-fill ultra universal restorative (SDI), and one conventional posterior resin-based composite (RBC), Heliomolar A3 (Ivoclar Vivadent), that were either 0.2 mm, 2 mm, or 4 mm thick were photocured using a modified Bluephase G4 (Ivoclar Vivadent) light-curing unit (LCU) that delivered a single emission band (wavelength centered at 449 nm). The same radiant exposure of 24 J/cm2 was delivered at irradiances ranging from 0.5 to 3 W/cm2 by adjusting the exposure time. PowerFill was also photocured for 3 s or 6 s using a Bluephase PowerCure LCU (Ivoclar Vivadent) on the 3 s mode setting. The degree of conversion (DC) was measured in real-time at a high temporal resolution at 30 °C using Attenuated Total Reflection (ATR) FTIR spectroscopy with a sampling rate of 13 DC data points per second. The DC data were analyzed using a phenomenological autocatalytic model. The RBC viscosity was measured at 21 °C and 30 °C. Light transmission through the RBC samples at 22 °C was monitored with time to calculate the extinction coefficients of the RBCs. RESULTS The time delay before photopolymerization started increased as the RBC thickness increased and the irradiance decreased. An autocatalytic model described the DC data. The time t0 was less than 77 ms for the 0.2 mm thick samples of PowerFill irradiated using the highest irradiance of 3 W/cm2. Among the three RBCs for each sample thickness and irradiance level, the PowerFill had the smallest time t0. There was a time delay of 0.59 s and 1.25 s before the DC started to increase at the bottom of 4 mm thick samples for the PowerFill and Aura, respectively, when an irradiance of 1 W/cm2 was delivered. The time delay increased to 3.65 s for the Aura when an irradiance of 0.5 W/cm2 was delivered. The extinction coefficients near 449 nm were 0.78 mm-1, 0.76 mm-1, and 1.55 mm-1 during the first 2 s after the start of photocuring of PowerFill, Aura, and Heliomolar, respectively. Only PowerFill followed exposure reciprocity. At T = 30 °C, the viscosity was 3400, 17000, and 5200 Paˑs for PowerFill, Aura, and Heliomolar, respectively. SIGNIFICANCE The time delay between when photopolymerization starts at the top and bottom of 2- or 4-mm thick RBC restorations may affect the structural integrity of the bond between the tooth and the bottom of the restoration. Only PowerFill followed exposure reciprocity between irradiance levels of 0.5 to 3 W/cm2. Exposure reciprocity did not occur for Aura or Heliomolar, neither of which are optimized for short light exposure or high irradiance conditions.
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Affiliation(s)
- Daniel Labrie
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Richard B Price
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Braden Sullivan
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Austyn M Salazar
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0596, United States
| | - Dixa Gautam
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0596, United States
| | - Jeffrey W Stansbury
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO, 80309-0596, United States; Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Jack L Ferracane
- Department of Restorative Dentistry, Oregon Health & Science University, Portland, OR, United States
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Babaier R, Haider J, Silikas N, Watts DC. Effect of CAD/CAM aesthetic material thickness and translucency on the polymerisation of light- and dual-cured resin cements. Dent Mater 2022; 38:2073-2083. [DOI: 10.1016/j.dental.2022.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/11/2022] [Accepted: 11/11/2022] [Indexed: 11/27/2022]
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Lopes-Rocha L, Hernandez C, Gonçalves V, Pinho T, Tiritan ME. Analytical Methods for Determination of BPA Released from Dental Resin Composites and Related Materials: A Systematic Review. Crit Rev Anal Chem 2022; 54:653-668. [PMID: 35776702 DOI: 10.1080/10408347.2022.2093097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Knowing the impacts of bisphenol A (BPA) on human health, this systematic review aimed to gather the analytical methods for the quantification of BPA release of BPA in dental materials in in vitro and in vivo (biological fluids) studies. A brief critical discussion of the impacts of BPA on human health and the possible association with BPA in dental materials was also presented. The research was carried out by three independent researchers, (according to PRISMA guidelines) in PUBMED and SCOPUS databases, by searching for specific keywords and articles published between January 2011 and February 2022. Seventeen articles met the eligibility criteria and were included in this systematic review: 10 in vitro and 7 in vivo. In in vitro studies, the highest amounts of BPA released were from flowable to conventional resins, followed by resin-modified glass ionomer. In contrast, the smallest amount was released from "BPA-free" composites and CAD-CAM blocks. Regarding in vivo studies, a higher concentration of BPA were found in saliva than urine or blood. The best analytical method for trace quantifying BPA is LC-MS/MS (Liquid Chromatography with Tandem Mass Spectrometry) due to its selectivity, low quantification limits, and the unequivocal identification. However, further studies are required to develop faster and more sensitive methods, in order to obtain more reliable results.
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Affiliation(s)
- Lígia Lopes-Rocha
- UNIPRO-Oral Pathology and Rehabilitation Research Unit, University Institute of Health Sciences (IUCS), CESPU, Gandra, Portugal
| | - Clara Hernandez
- UNIPRO-Oral Pathology and Rehabilitation Research Unit, University Institute of Health Sciences (IUCS), CESPU, Gandra, Portugal
| | - Virgínia Gonçalves
- UNIPRO-Oral Pathology and Rehabilitation Research Unit, University Institute of Health Sciences (IUCS), CESPU, Gandra, Portugal
- TOXRUN-Toxicology Research Unit, University Institute of Health Sciences (IUCS), CESPU, Gandra, Portugal
| | - Teresa Pinho
- UNIPRO-Oral Pathology and Rehabilitation Research Unit, University Institute of Health Sciences (IUCS), CESPU, Gandra, Portugal
- IBMC-Institute of Molecular and Cellular Biology, i3S-Institute of Innovation and Research in Health, Oporto University, Porto, Portugal
| | - Maria Elizabeth Tiritan
- TOXRUN-Toxicology Research Unit, University Institute of Health Sciences (IUCS), CESPU, Gandra, Portugal
- Faculty of Pharmacy, University of Porto (FFUP), Portugal. Interdisciplinary Center of Marine and Environmental Research (CIIMAR), University of Porto, Edifício do Terminal de Cruzeiros do Porto de Leixões, Matosinhos, Portugal
- Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, Faculdade de Farmácia da, Universidade do Porto, Porto, Portugal
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German MJ. Developments in resin-based composites. Br Dent J 2022; 232:638-643. [PMID: 35562465 PMCID: PMC9106574 DOI: 10.1038/s41415-022-4240-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/21/2022] [Indexed: 11/10/2022]
Abstract
With the phasing down of dental amalgam use in response to the Minamata Convention, it is likely that resin-based composite restoratives will be the dental material of choice for the direct restoration of compromised dentition in the UK, at least for the foreseeable future. The current materials have a finite lifespan, with failures predominately due to either secondary caries or fracture. Consequently, there is considerable in vitro research reported each year with the intention of producing improved materials. This review describes the recent research in materials designed to have low polymerisation shrinkage and increased mechanical properties. Also described is research into materials that are either antimicrobial or are designed to release ions into the surrounding oral environment, with the aim of stimulating remineralisation of the surrounding dental tissues. It is hoped that by describing this recent research, clinicians will be able to gain some understanding of the current research that will potentially lead to new products that they can use to improve patient treatment in the future. Provides an overview of recent research developments aimed at improving the performance of resin-based composites. Details the recent developments in monomers and fillers to produce resin-based composites that either have lower polymerisation shrinkage or better mechanical properties compared to current commercially available products. Describes recent research on developing resin-based composites that can act as potential sources of antimicrobial or remineralising agents.
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Affiliation(s)
- Matthew J German
- School of Dental Sciences, Translational and Clinical Research Institute, Newcastle University, Framlington Place, Newcastle upon Tyne, UK.
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Depth of cure of 10 resin-based composites light-activated using a laser diode, multi-peak, and single-peak light-emitting diode curing lights. J Dent 2022; 122:104141. [PMID: 35483497 DOI: 10.1016/j.jdent.2022.104141] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVES To evaluate the depth of cure (DOC) of ten contemporary resin-based composites (RBCs), light-cured using different LCUs and exposure times. METHODS The power, radiant emittance, irradiance, radiant exposure (RE), and beam profiles from a laser (M, Monet), a multi-peak (V, Valo Grand), and single-peak (S, SmartLite Pro) LCU were measured. The DOC was measured using a 6-mm diameter metal mold and a solvent dissolution method to remove the uncured RBC. The length of the remaining RBC was divided by 2. The exposure times were: 1s and 3s for M, 10s and 20s for V, and 10s and 20s for S. Data were analyzed using: Bland-Altman distribution, Pearson's Correlation, and an artificial neural network (ANN) to establish the relative importance of the factors on the DOC (α=0.05; β=0.2). RESULTS Significant differences were found in the DOC of the different LCUs and composites. The laser LCU emitted the highest power, radiant emittance, and irradiance. However, this LCU used for 1 s delivered the lowest RE and produced the shortest DOC in all ten RBCs. The ANN demonstrated that the RE is the most critical factor for the DOC. Bland-Altman comparisons showed that the DOCs achieved with the laser LCU used for 1s were between 17 - 34 % shorter than the other conditions. CONCLUSIONS Although the laser LCU cured all 10 RBCs when used for 1s, it produced the shallowest DOC, and some RBCs did not achieve the minimum DOC threshold. The RE and not the irradiance was the most important factor in determining the DOC of RBCs. CLINICAL SIGNIFICANCE Despite delivering high power and irradiance, the laser used for l s delivered a lower radiant exposure than the conventional LCUs used for 10 s. This resulted in a shorter DOC.
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Influence of Dimethacrylate Monomer on the Polymerization Efficacy of Resin-Based Dental Cements-FTIR Analysis. Polymers (Basel) 2022; 14:polym14020247. [PMID: 35054654 PMCID: PMC8781089 DOI: 10.3390/polym14020247] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/12/2021] [Accepted: 09/14/2021] [Indexed: 01/27/2023] Open
Abstract
The degree of polymerization for dimethacrylate resin-based materials (BisGMA, TEGDMA, UDMA, HEMA) ranges from 55 to 75%. Literature data indicate that polymerization efficacy depends, among other factors, on the type of methacrylate resin comprising the material. The aim of this study was to evaluate the polymerization efficacy of four dental cement materials characterized by different polymerization mechanisms using FTIR analysis. In the present study, the FTIR method was adopted to analyze the degree of polymerization efficacy of four resin-based dental cement materials, two of which were self-cured and two were dual-cured cements. The IR spectral analysis was performed 24 h after the polymerization of the cementitious material. RelyX ARC cement exhibits the lowest polymerization efficacy (61.3%), while that of Variolink II (85.8%) and Maxcem Elite is the highest (90.1%). Although the efficacy of self-cured cements appears to be superior, the difference is not statistically significant (p = 0.280). Polymerization efficacy largely depends on the chemical structure of the material in terms of the presence of a particular methacrylate resin and less on the polymerization mechanism itself, i.e., whether it is a self-cured or dually cured dental cement. Thus, in clinical practice, cementitious materials with a higher proportion of TEGDMA compared with BisGMA are recommended.
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Aldhafyan M, Silikas N, Watts DC. Influence of curing modes on conversion and shrinkage of dual-cure resin-cements. Dent Mater 2021; 38:194-203. [PMID: 34924201 DOI: 10.1016/j.dental.2021.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/03/2021] [Accepted: 12/03/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To explore the effect of curing modes of dual-cure resin cements on their degree of conversion (DC) and polymerization shrinkage (PS) over specific post-activation periods. METHODS Five self-adhesive (PANAVIA SA, RelyX Universal Resin, RelyX Unicem 2, Bifix SE, and SpeedCEM Plus) and three conventional (PANAVIA V5, Nexus Third Generation, and RelyX Ultimate Universal) dual-cure resin cements were studied. Four specimens (n = 4) were made per curing mode (light/self-cure) to measure either DC or PS. FTIR was utilized to measure real-time DC (%) over 24 h. The Bonded Disk method was used to measure shrinkage at 23 °C over 1 h. The data were analyzed using one-way ANOVA, Tukey post-hoc tests and independent/ paired sample t-tests (a = 0.05). RESULTS After 1 h post-activation, the DC of light-cured (LC) specimens ranged between 66.6% and 77.4%, whereas for self-cured (SC) specimens DC ranged between 44.4% and 73.2%. After 24 h, the DC of LC specimens ranged between 74.8% and 82.4% and between 62.7% and 81.7% for SC specimens. After 24 h, the DC of three cements (BSE, PV5, and RXU) were comparable between their curing modes (p > 0.05), whereas five cements (CEM, NX3, PSA, RXU2, RXL) had significantly lower DC for SC compared to LC specimens (p < 0.05). After 1 h post-activation, shrinkage ranged between 5.9% and 8.5% for LC and between 4.9% and 8.3% for SC specimens. Most cements were not significantly different between curing modes. However, light-cured PAS, RXL and RXU2 had significantly higher shrinkage (p < 0.05). After 1 h post-activation, a strong positive correlation existed between conversion and shrinkage (LC: r2 = 0.95 and SC: r2 = 0.93). SIGNIFICANCE Whenever light access is possible, light-curing of resin-cements remains beneficial to the overall efficacy of their conversion and thus all factors that depend on that. Conversion and shrinkage behavior are intrinsically important factors in clinical selection of resin-cement products.
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Affiliation(s)
- Mohammed Aldhafyan
- Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Division of Dental Biomaterials Science, College of Dentistry, King Saud University, Saudi Arabia
| | - Nikolaos Silikas
- Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK.
| | - David C Watts
- Biomaterials Science, Division of Dentistry, School of Medical Sciences, University of Manchester, UK; Photon Science Institute, University of Manchester, UK.
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Serino G, Comba A, Baldi A, Carossa M, Baldissara P, Bignardi C, Audenino A, Torres CGR, Scotti N. Could light-curing time, post-space region and cyclic fatigue affect the nanomechanical behavior of a dual-curing cement for fiber post luting? J Mech Behav Biomed Mater 2021; 125:104886. [PMID: 34695660 DOI: 10.1016/j.jmbbm.2021.104886] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/29/2021] [Accepted: 10/04/2021] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To evaluate the effects of curing time, post-space region and cyclic fatigue on the micromechanical properties of a fiber-post luting cement. The null hypotheses were that (1) curing time, (2) fatigue and (3) post-space region does not affect the nanoindentation modulus and hardness of the dual-curing cement. MATERIALS AND METHODS 48 premolars were endodontically treated and a class I cavity and 8 mm deep post space was prepared. Fiber posts were luted with a universal, dualized adhesive system and a dual-curing cement following manufacturer's instructions. Specimens were divided into three groups (16 specimens for each group) according to light-curing time (no light-curing, 20 s light-curing and 120 s light-curing), which was performed with a LED lamp at 1000 mW/cm 2. The coronal part of the cavity was restored using a nano-filled resin composite. After 24 h, 8 specimens for each group were randomly extract in order to undergo to fatigue test in wet condition through a chewing simulator, while the other specimens were kept in distilled water as benchmark. All the restored teeth were then sectioned in 1 mm thick slices perpendicularly to the fiber post axis. Specimen slices were classified in coronal and apical to be tested through a nanoindenter. Data were analyzed through Kruskal-Wallis test with a significance level of 1%, in order to evaluate the influence of treatments (i.e., curing time and cyclic loading) on the micromechanical properties of the tested luting cement. RESULTS Both fatigue and curing time significantly influenced nanoindentation modulus and hardness of dual-curing cement (p < 0.01). No significant differences were reported for post space region. A significant interaction was found among the analyzed factors (p < 0.01). SIGNIFICANCE 120 s light-curing time is recommended in order to achieve optimal mechanical proprieties, independently from post space region and cyclic fatigue. As matter of fact, 120 s light-curing allowed to prevent strain hardening induced by the fatigue simulation.
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Affiliation(s)
- Gianpaolo Serino
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy; Polito BIO Med Lab, Politecnico di Torino, Turin, Italy
| | - Allegra Comba
- Department of Surgical Sciences, Dental School, Turin, Italy
| | - Andrea Baldi
- Department of Surgical Sciences, Dental School, Turin, Italy
| | - Massimo Carossa
- Department of Surgical Sciences, Dental School, Turin, Italy
| | - Paolo Baldissara
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Cristina Bignardi
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy; Polito BIO Med Lab, Politecnico di Torino, Turin, Italy
| | - Alberto Audenino
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy; Polito BIO Med Lab, Politecnico di Torino, Turin, Italy
| | - Carlos Gomes Rocha Torres
- Department of Restorative Dentistry, Sao Paulo State University - UNESP, Sao Jose Dos Campos, Brazil
| | - Nicola Scotti
- Department of Surgical Sciences, Dental School, Turin, Italy.
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Ridha AM, Aidinis K, Suliman AH. Temperature Rise at the Pulp-Dentin Junction for a Multi-Layered Composite Restoration using the Finite Element Method. Open Dent J 2021. [DOI: 10.2174/1874210602115010487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objectives:
During the light-curing process of composite restoration, excessive heat can be produced, which can potentially lead to pulp necrosis (death). In this study, we aimed, based on the Finite Element Method (FEM), to assess the risk of pulp damage during the light-curing process by investigating the influence of light-curing devices, under various irradiation regimes, on the temperature increase at the pulp-dentin junction, during a one-layer or multi-layered deep composite restoration.
Methods:
A Three-dimensional finite element method model of typical geometry and material properties, as commonly reported in the literature, was employed in COMSOL Multiphysics simulations in order to determine the temperature increase in the pulp. Various combinations of light intensities, durations, and irradiation regimes were investigated for the two cases, of shallow and deep multi-layered composite restoration.
Results:
Results of light-curing composite resins within enamel; indicate that the temperature rise during the curing process was within the safety margins. Results of light-curing composite resin restorations closer to the pulp with thin remaining dentin, indicate a temperature increase that could be sufficient to cause thermal injury in the pulp. Modulating the light output marginally, reduced the temperature rise while reducing the intensity and increasing the curing duration which was consistently more effective in this respect.
Conclusion:
The results clearly demonstrate that with currently adopted standard procedures, there exists a risk of thermal injury during multi-layered composite restorations with thin remaining dentin; it is thus important to establish appropriate curing regimes that would lead to minimal temperature increase during deep composite restorations and hence reduce the risk of thermal injury to the pulp.
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13
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Lopes-Rocha L, Ribeiro-Gonçalves L, Henriques B, Özcan M, Tiritan ME, Souza JCM. An integrative review on the toxicity of Bisphenol A (BPA) released from resin composites used in dentistry. J Biomed Mater Res B Appl Biomater 2021; 109:1942-1952. [PMID: 33834604 DOI: 10.1002/jbm.b.34843] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/02/2021] [Accepted: 03/28/2021] [Indexed: 11/11/2022]
Abstract
The main aim of this study was to perform an integrative review on the release of bisphenol A (BPA) from resin-matrix composites and potential toxic effects. A bibliographic search was performed on the PubMed platform using the following keywords: "Bisphenol A" OR "BPA" AND "resin composite" OR "composite resin" AND "toxicity" OR "cytotoxicity" OR "release". Inclusion criteria involved in vitro and in vivo studies on the release and toxicity of BPA. Results highlighted the release of BPA from resin-matrix composites due to insufficient polymerization and/or degradation of the polymeric matrix. BPA is part of the organic matrix of resin-matrix composites and may be hydrolysed in human saliva, although studies report that low doses might not be detected by traditional chemical analysis. Studies exposing zebrafish embryos to different concentrations of Bis-GMA, showed 55% mortality at 10 μM Bis-GMA while 30% mortality was recorded at 1 μM Bis-GMA. In patients, a BPA concentration of around 2.09 × 10-2 μg/ml was found in the saliva after placement of lingual orthodontic retainers with resin-matrix composites. Also, the BPA molecule can be swallowed and absorbed by the oral/gastrointestinal mucosa, which might result in systemic toxicity. The degradation of resin-matrix composites and release of BPA in oral environment are dependent on the organic matrix content and on the polymerization method. A increased release of BPA can lead to the absorption into oral and gastrointestinal mucosa with high risks of local and systemic toxicity.
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Affiliation(s)
- Lígia Lopes-Rocha
- Department of Dental Sciences, University Institute of Health Sciences (IUCS), CESPU, Gandra, PRD, Portugal.,Institute for Research and Advanced Training in Health Sciences and Technologies (IINFACTS), CESPU, Gandra PRD, Portugal
| | - Lara Ribeiro-Gonçalves
- Department of Dental Sciences, University Institute of Health Sciences (IUCS), CESPU, Gandra, PRD, Portugal
| | - Bruno Henriques
- Ceramic and Composite Materials Research Group (CERMAT), Dept. of Mechanical Engineering (EMC), Federal University of Santa Catarina (UFSC), Florianópolis, Brazil.,Centre for Microelectromechanical Systems (CMEMS-UMINHO), University of Minho, Campus Azurém, Guimarães, Braga, Portugal
| | - Mutlu Özcan
- Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Center of Dental Medicine, University of Zürich, Zürich, Switzerland
| | - Maria Elizabeth Tiritan
- Institute for Research and Advanced Training in Health Sciences and Technologies (IINFACTS), CESPU, Gandra PRD, Portugal.,Laboratory of Organic and Pharmaceutical Chemistry (LQOF), Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Júlio C M Souza
- Department of Dental Sciences, University Institute of Health Sciences (IUCS), CESPU, Gandra, PRD, Portugal.,Centre for Microelectromechanical Systems (CMEMS-UMINHO), University of Minho, Campus Azurém, Guimarães, Braga, Portugal
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14
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Impact of Fast High-Intensity versus Conventional Light-Curing Protocol on Selected Properties of Dental Composites. MATERIALS 2021; 14:ma14061381. [PMID: 33809096 PMCID: PMC8000385 DOI: 10.3390/ma14061381] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 11/16/2022]
Abstract
To study the influence of fast high-intensity (3-s) and conventional (20-s) light curing protocols on certain physical properties including light-transmission and surface wear of two nano-hybrid composite resins (Tetric PowerFill and Essentia U) specifically designed for both curing protocols. According to ISO standards, the following properties were investigated: flexural properties, fracture toughness and water sorption/solubility. FTIR-spectrometry was used to calculate the double bond conversion (DC%). A wear test using a chewing simulator was performed with 15,000 chewing cycles. A tensilometer was used to measure the shrinkage stress. Light transmission through various thicknesses (1, 2, 3 and 4 mm) of composite resins was quantified. The Vickers indenter was utilized for evaluating surface microhardness (VH) at the top and the bottom sides. Scanning electron microscopy was utilized to investigate the microstructure of each composite resin. The light curing protocol did not show a significant (p > 0.05) effect on the mechanical properties of tested composite resins and differences were material-dependent. Shrinkage stress, DC% and VH of both composite resins significantly increased with the conventional 20 s light curing protocol (p < 0.05). Light curing conventional composite resin with the fast high-intensity (3-s) curing protocol resulted in inferior results for some important material properties.
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15
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Degree of conversion and in vitro temperature rise of pulp chamber during polymerization of flowable and sculptable conventional, bulk-fill and short-fibre reinforced resin composites. Dent Mater 2021; 37:983-997. [PMID: 33714623 DOI: 10.1016/j.dental.2021.02.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/03/2021] [Accepted: 02/24/2021] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Determine the degree of conversion (DC) and in vitro pulpal temperature (PT) rise of low-viscosity (LV) and high-viscosity (HV) conventional resin-based composites (RBC), bulk-fill and short-fibre reinforced composites (SFRC). METHODS The occlusal surface of a mandibular molar was removed to obtain dentine thickness of 2 mm above the roof of the pulp chamber. LV and HV conventional (2 mm), bulk-fill RBCs (2-4 mm) and SFRCs (2-4 mm) were applied in a mold (6 mm inner diameter) placed on the occlusal surface. PT changes during the photo-polymerization were recorded with a thermocouple positioned in the pulp chamber. The DC at the top and bottom of the samples was measured with micro-Raman spectroscopy. ANOVA and Tukey's post-hoc test, multivariate analysis and partial eta-squared statistics were used to analyze the data (p < 0.05). RESULTS The PT changes ranged between 5.5-11.2 °C. All LV and 4 mm RBCs exhibited higher temperature changes. Higher DC were measured at the top (63-76%) of the samples as compared to the bottom (52-72.6%) in the 2 mm HV conventional and bulk-fill RBCs and in each 4 mm LV and HV materials. The SFRCs showed higher temperature changes and DC% as compared to the other investigated RBCs. The temperature and DC were influenced by the composition of the material followed by the thickness. SIGNIFICANCE Exothermic temperature rise and DC are mainly material dependent. Higher DC values are associated with a significant increase in PT. LV RBCs, 4 mm bulk-fills and SFRCs exhibited higher PTs. Bulk-fills and SFRCs applied in 4 mm showed lower DCs at the bottom.
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Butterhof M, Ilie N. Mathematical model for assessing true irradiance received by luting materials while curing through modern CAD/CAM resin composites. Dent Mater 2020; 36:e255-e265. [DOI: 10.1016/j.dental.2020.04.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/21/2020] [Accepted: 04/28/2020] [Indexed: 10/24/2022]
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17
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Shimokawa C, Turbino ML, Giannini M, Braga RR, Price RB. Effect of Curing Light and Exposure Time on the Polymerization of Bulk-Fill Resin-Based Composites in Molar Teeth. Oper Dent 2020; 45:E141-E155. [PMID: 32053458 DOI: 10.2341/19-126-l] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES This study examined the influence of different light-curing units (LCUs) and exposure times on the microhardness across bulk-fill resin-based composite (RBC) restorations in a molar tooth. METHODS AND MATERIALS Tip diameter, radiant power, radiant exitance, emission spectra, and light beam profile were measured on two single-emission-peak LCUs (Celalux 3 and DeepCure-S) and two multiple-peak LCUs (Bluephase 20i and Valo Grand). A mold was made using a human molar that had a 12-mm mesial-distal length, a 2.5-mm deep occlusal box, and two 4.5-mm deep proximal boxes. Two bulk-fill RBCs (Filtek Bulk Fill Posterior and Tetric EvoCeram Bulk Fill) were photoactivated for 10 seconds and for 20 seconds, with the light guide positioned at the center of the occlusal surface. Microhardness was then measured across the transverse surface of the restorations. The light that reached the bottom of the proximal boxes was examined. Data were statistically analyzed with the Student t-test, two-way analysis of variance, and the Tukey post hoc test (α=0.05). RESULTS The four LCUs were different regarding all the tested characteristics. Even when using LCUs with wide tips and a homogeneous beam profile, there were significant differences in the microhardness results obtained at the central and proximal regions of the RBCs (p<0.05). LCUs with wider tips used for 20 seconds produced higher microhardness values (p<0.05). The multiple-peak LCUs produced greater hardness values in Tetric EvoCeram Bulk Fill than did the single-emission-peak LCUs (Celalux 3 and DeepCure-S). Results for the light measured at the bottom of proximal boxes showed that little light reached these regions when the light tip was positioned at the center of restorations. CONCLUSIONS Curing lights with wide tips, homogeneous light beam profiles, and longer exposure times are preferred when light-curing large MOD restorations. Light curing from more than one position may be required for adequate photopolymerization.
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18
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Sirovica S, Guo Y, Guan R, Skoda MWA, Palin WM, Morrell AP, Romanyk DL, Martin RA, Addison O. Photo-polymerisation variables influence the structure and subsequent thermal response of dental resin matrices. Dent Mater 2020; 36:343-352. [PMID: 31924386 DOI: 10.1016/j.dental.2019.12.004] [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: 09/24/2019] [Revised: 11/20/2019] [Accepted: 12/11/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE The structure of the polymer phase of dental resin-based-composites is highly sensitive to photo-polymerisation variables. The objective of this study was to understand how different polymer structures, generated with different photo-polymerisation protocols, respond to thermal perturbation. METHODS Experimental resins were prepared from a series of Bis-GMA/TEGDMA blends (40/60, 50/50 and 60/40 wt.%), with either Camphorquinone/DMAEMA or Lucirin TPO as the photo-initiator system. Resins were photo-polymerised, in a disc geometry, at either relatively 'high' (3000 mW cm-2 for 6 s) or 'low' (300 mW cm-2 for 60 s) irradiances ensuring matched radiant exposures (18 J cm-2). Specimens were heated, from 20-160 °C at a rate of 5 °C min-1, whilst simultaneous synchrotron X-ray scattering measurements were taken at 5 °C increments to determine changes in polymer chain segment extension and medium-range order as a function of temperature. For each unique resin composition (n = 3), differential scanning calorimetry was used to measure glass transition temperatures using the same heating protocol. A paired t-test was used to determine significant differences in the glass transition temperature between irradiance protocols and photo-initiator chemistry at ɑ = 0.05. RESULTS Resins pre-polymerised through the use of TPO and or high irradiances demonstrated a reduced rate of chain extension indicative of lower thermal expansion and a larger decrease in relative order when heated below the glass transition temperature. Above the transition temperature, differences in the rate of chain extension were negligible, but slower converted systems showed greater relative order. There was no significant difference in the glass transition temperature between different photo-initiator systems or irradiance protocols. SIGNIFICANCE The evolution of chain extension and medium-range order during heating is dependent on the initial polymer structure which is influenced by photo-polymerisation variables. Less ordered systems, generated at faster rates of reactive group conversion displayed reduced chain extension below the glass transition temperature and maintained lower order throughout heating.
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Affiliation(s)
- Slobodan Sirovica
- Aston Institute of Materials Research, School of Engineering & Applied Science, Aston University, Birmingham, B4 7ET, UK; Faculty of Dental, Oral and Craniofacial Science, King's College London, Guy's Hospital, London, SE1 9RT, UK.
| | - Yilan Guo
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, T6G 1C9, Canada
| | - Raymond Guan
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, T6G 1C9, Canada
| | - Maximilian W A Skoda
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0QX, UK
| | - William M Palin
- College of Medical and Dental Sciences, Institute of Clinical Sciences, School of Dentistry, University of Birmingham, Mill Pool Way, Edgbaston, Birmingham, B5 7EG, UK
| | - Alexander P Morrell
- Aston Institute of Materials Research, School of Engineering & Applied Science, Aston University, Birmingham, B4 7ET, UK; Faculty of Dental, Oral and Craniofacial Science, King's College London, Guy's Hospital, London, SE1 9RT, UK
| | - Dan L Romanyk
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, T6G 1C9, Canada; Department of Mechanical Engineering, University of Alberta, Edmonton, T6G 1H9, Canada
| | - Richard A Martin
- Aston Institute of Materials Research, School of Engineering & Applied Science, Aston University, Birmingham, B4 7ET, UK
| | - Owen Addison
- Faculty of Dental, Oral and Craniofacial Science, King's College London, Guy's Hospital, London, SE1 9RT, UK; Faculty of Medicine and Dentistry, University of Alberta, Edmonton, T6G 1C9, Canada
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Palagummi SV, Hong T, Wang Z, Moon CK, Chiang MYM. Resin viscosity determines the condition for a valid exposure reciprocity law in dental composites. Dent Mater 2019; 36:310-319. [PMID: 31866065 DOI: 10.1016/j.dental.2019.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 12/04/2019] [Accepted: 12/04/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To provide conditions for the validity of the exposure reciprocity law as it pertains to the photopolymerization of dimethacrylate-based dental composites. METHODS Composites made from different mass ratios of resin blends (Bis-GMA/TEGDMA and UDMA/TEGDMA) and silanized micro-sized glass fillers were used. All the composites used camphorquinone and ethyl 4-dimethylaminobenzoate as the photo initiator system. A cantilever beam-based instrument (NIST SRI 6005) coupled with NIR spectroscopy and a microprobe thermocouple was used to simultaneously measure the degree of conversion (DC), the polymerization stress (PS) due to the shrinkage, and the temperature change (TC) in real time during the photocuring process. The instrument has an integrated LED light curing unit providing irradiances ranging from 0.01W/cm2 to 4W/cm2 at a peak wavelength of 460nm (blue light). Vickers hardness of the composites was also measured. RESULTS For every dental composite there exists a minimum radiant exposure required for an adequate polymerization (i.e., insignificant increase in polymerization with any further increase in the radiant exposure). This minimum predominantly depends on the resin viscosity of composite and can be predicted using an empirical equation established based on the test results. If the radiant exposure is above this minimum, the exposure reciprocity law is valid with respect to DC for high-fill composites (filler contents >50% by mass) while invalid for low-fill composites (that are clinically irrelevant). SIGNIFICANCE The study promotes better understanding on the applicability of the exposure reciprocity law for dental composites. It also provides a guidance for altering the radiant exposure, with the clinically available curing light unit, needed to adequately cure the dental composite in question.
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Affiliation(s)
- Sri Vikram Palagummi
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, United States
| | - Taeseung Hong
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, United States; Department of Materials Science and Engineering, Pukyong National University, Busan, Republic of Korea
| | - Zhengzhi Wang
- Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan, Hubei, China
| | - Chang Kwon Moon
- Department of Materials Science and Engineering, Pukyong National University, Busan, Republic of Korea
| | - Martin Y M Chiang
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, United States.
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HORI M, FUJIMOTO K, ASAKURA M, NAGASE Y, MIEKI A, KAWAI T. Measurement of exothermic heat released during polymerization of a lightcuring composite resin: Comparison of light irradiation modes. Dent Mater J 2019; 38:646-653. [DOI: 10.4012/dmj.2018-158] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Miki HORI
- Department of Dental Materials Science, School of Dentistry, Aichi Gakuin University
| | - Kotaro FUJIMOTO
- Department of Dental Materials Science, School of Dentistry, Aichi Gakuin University
| | - Masaki ASAKURA
- Department of Dental Materials Science, School of Dentistry, Aichi Gakuin University
| | - Yoshinori NAGASE
- Department of Dental Materials Science, School of Dentistry, Aichi Gakuin University
| | - Akimichi MIEKI
- Department of Dental Materials Science, School of Dentistry, Aichi Gakuin University
| | - Tatsushi KAWAI
- Department of Dental Materials Science, School of Dentistry, Aichi Gakuin University
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21
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Sirovica S, Skoda MWA, Podgorski M, Thompson PBJ, Palin WM, Guo Y, Smith AJ, Dewan K, Addison O, Martin RA. Structural Evidence That the Polymerization Rate Dictates Order and Intrinsic Strain Generation in Photocured Methacrylate Biomedical Polymers. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b00133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Slobodan Sirovica
- Aston Institute of Materials Research, School of Engineering & Applied Science, University of Aston, Birmingham B4 7ET, U.K
| | - Maximilian W. A. Skoda
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX, U.K
| | - Maciej Podgorski
- Department of Chemical and Biological Engineering, University of Colorado Boulder, 596 UCB Boulder, Colorado 80309, United States
- Faculty of Chemistry, Department of Polymer Chemistry, Maria Curie-Sklodowska University, Gliniana Street 33, 20-614 Lublin, Poland
| | | | - William M. Palin
- College of Medical and Dental Sciences, Institute of Clinical Sciences, School of Dentistry, University of Birmingham, Mill Pool Way,
Edgbaston, Birmingham B5 7EG, U.K
| | - Yilan Guo
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton T6G 1C9, Canada
| | - Andrew J. Smith
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K
| | - Karun Dewan
- College of Medical and Dental Sciences, Institute of Clinical Sciences, School of Dentistry, University of Birmingham, Mill Pool Way,
Edgbaston, Birmingham B5 7EG, U.K
| | - Owen Addison
- College of Medical and Dental Sciences, Institute of Clinical Sciences, School of Dentistry, University of Birmingham, Mill Pool Way,
Edgbaston, Birmingham B5 7EG, U.K
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton T6G 1C9, Canada
| | - Richard A. Martin
- Aston Institute of Materials Research, School of Engineering & Applied Science, University of Aston, Birmingham B4 7ET, U.K
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Long-term elution of monomers from resin-based dental composites. Dent Mater 2019; 35:477-485. [DOI: 10.1016/j.dental.2019.01.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/09/2019] [Accepted: 01/09/2019] [Indexed: 11/19/2022]
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Aldossary MS, Abu Hajia SS, Santini A. Transmission de l’énergie lumineuse au travers de six marques différentes d’attaches orthodontiques. Int Orthod 2018; 16:638-651. [DOI: 10.1016/j.ortho.2018.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ajaj RA, Nassar HM, Hasanain FA. Infection Control Barrier and Curing Time as Factors Affecting the Irradiance of Light-Cure Units. J Int Soc Prev Community Dent 2018; 8:523-528. [PMID: 30596043 PMCID: PMC6280572 DOI: 10.4103/jispcd.jispcd_226_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 09/18/2018] [Indexed: 11/04/2022] Open
Abstract
Objective The objective of the study is to investigate the effect of infection control barrier (ICB) and curing time on irradiance of light cure units (LCUs). Methods Irradiance (mW/cm2) of the LCUs at a government dental school were recorded with and without ICB at 0 (T0), 10 (T10), and 20 (T20) seconds using a digital radiometer. Data were analyzed using IBM® SPSS® Statistics Version 17 for Windows software for the analysis of variance and Bonferroni methods at 0.05 significance level. Results Using ICB resulted in a statistically significant effect on the irradiance mean (P < 0.01). A significant difference existed between the four different brands of LCUs at different time intervals, irrespective of the use of ICB. At T0 and T10, the mean output of Acteon mini-light-emitting diode (LED) was significantly higher than that of either the Kerr Demi Ultra or the Kavo Polylux II. At T20, E-Morlit's mean irradiance was significantly higher than that of Kerr Demi Ultra, which in turn was significantly higher than that of the Kavo PolyLux II. The mean irradiance of the LEDs was significantly higher than that of the halogens irrespective of barrier placement and at all-time points. Conclusion The ICB used in this study resulted in a statistically significant reduction in the irradiance output. No significant difference in the irradiance was found at different curing time intervals for the tested units regardless of ICB usage.
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Affiliation(s)
- Reem A Ajaj
- Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hani M Nassar
- Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Fatin A Hasanain
- Department of Restorative Dentistry, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia
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Abstract
OBJECTIVE To measure Total Light Energy (TLE) Transmission through six makes of ceramic orthodontic brackets alone and bracket-plus-adhesive samples, using the MARC™-Resin Calibrator (RC). METHODS Six makes, three each monocrystalline (M) and polycrystalline (P) were used; PureSapphire (M), SPA Aesthetic (M), Ghost (M), Mist (P), Reflections (P), and Dual Ceramic (P). The Ortholux™ Light Curing Unit (LCU) was used to cure the orthodontic adhesive Transbond™XT. The LCU's tip irradiance was measured and TLE transmitted through the ceramic bracket was obtained, then adhesive added to the bracket, and transmitted TLE measured through bracket-plus-adhesive samples. The LCU was set at five seconds as recommended for curing adhesive through ceramic brackets. RESULTS Mean tip irradiance was 1859.2±16.2mW/cm2. The TLE transmitted through brackets alone ranged 1.7 to 3.9J/cm2, in the descending order: Ghost>Pure Sapphire>Reflections>Mist>SPA Aesthetics>Dual Ceramic. The TLE transmitted through bracket-plus-adhesive samples ranged 1.6 to 3.7J/cm2, in the descending order: Ghost>Mist>Reflections>Pure Sapphire>SPA Aesthetics>Dual Ceramic. TLE was reduced with the addition of adhesive (range -0.1 to -0.7J/cm2). There was a significant difference for Pure Sapphire, Reflections, and Mist (P<0.05), but not for SPA Aesthetics, Ghost, and Dual Ceramic. There was no overall significant difference between the monocrystalline and polycrystalline makes. The two best makes were of the monocrystalline type, concerning TLE transmission, but with the exception of polycrystalline Dual Ceramic; the next worst make was a monocrystalline bracket, SPA Aesthetics. CONCLUSION Light energy attenuation through ceramic orthodontic brackets is make-dependent, with no overall difference between monocrystalline and polycrystalline brackets. Light energy is further attenuated with the addition of resin-based orthodontic adhesive.
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Daugherty MM, Lien W, Mansell MR, Risk DL, Savett DA, Vandewalle KS. Effect of high-intensity curing lights on the polymerization of bulk-fill composites. Dent Mater 2018; 34:1531-1541. [DOI: 10.1016/j.dental.2018.06.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 05/25/2018] [Accepted: 06/07/2018] [Indexed: 10/28/2022]
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Shim JS, Han SH, Jha N, Hwang ST, Ahn W, Lee JY, Ryu JJ. Effect of Irradiance and Exposure Duration on Temperature and Degree of Conversion of Dual-Cure Resin Cement for Ceramic Restorations. Oper Dent 2018; 43:E280-E287. [PMID: 30106334 DOI: 10.2341/17-283-l] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study investigated the effects of irradiance and exposure duration on dual-cured resin cements irradiated through ceramic restorative materials. A single light-curing unit was calibrated to three different irradiances (500, 1000, and 1500 mW/cm2) and irradiated to three different attenuating materials (transparent acryl, lithium disilicate, zirconia) with 1-mm thicknesses for 20 or 60 seconds. The changes in irradiance and temperature were measured with a radiometer (or digital thermometer) under the attenuating materials. The degree of conversion (DC) of dual-cure resin cement after irradiation at different irradiances and exposure durations was measured with Fourier transform near infrared spectroscopy. Two-way analysis of variance revealed that irradiance ( p<0.001) and exposure duration ( p<0.001) significantly affected temperature and DC. All groups showed higher DCs with increased exposure times ( p<0.05), but there were no statistically significant differences between the groups irradiated with 1000 mW/cm2 and 1500 mW/cm2 ( p>0.05). Higher-intensity irradiances yielded higher temperatures ( p<0.05), but exposure time did not affect temperature when materials were irradiated at 500 mW/cm2 ( p>0.05).
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Shimokawa CAK, Turbino ML, Giannini M, Braga RR, Price RB. Effect of light curing units on the polymerization of bulk fill resin-based composites. Dent Mater 2018; 34:1211-1221. [PMID: 29801683 DOI: 10.1016/j.dental.2018.05.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/15/2018] [Accepted: 05/02/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine the potential effect of four different light curing units (LCUs) on the curing profile of two bulk fill resin-based composites (RBCs). METHODS Four LCUs (Bluephase 20i, Celalux 3, Elipar DeepCure-S and Valo Grand) were used to light cure two RBCs (Filtek Bulk Fill Posterior Restorative and Tetric EvoCeram Bulk Fill). The effective tip diameter, radiant power, radiant emittance, emission spectrum and light beam profile of the LCUs were measured. Knoop microhardness was measured at the top and bottom surfaces of RBC specimens that were 12-mm in diameter and 4-mm deep (n=5). The distribution of the spectral radiant power that was delivered to the surface of the specimen and the light transmission through the 4-mm thick specimens was measured using an integrating sphere. Two-way ANOVA and Tukey tests (α=0.05) were applied. RESULTS The Valo Grand produced the most homogeneous microhardness across the surfaces of the RBCs (p>0.05). When the Celalux 3, Bluephase 20i and Elipar DeepCure-S lights were used, the center of the specimens achieved greater hardness values compared to their outer regions (p<0.05). Approximately 10% of the radiant power delivered to the top reached the bottom of the specimen, although almost no violet light passed through 4mm of either RBC. A positive correlation was observed between the radiant exposure and microhardness. SIGNIFICANCE The characteristics of the LCUs influenced the photoactivation of the RBCs. The use of a wide tip with a homogeneous light distribution is preferred when light curing RBCs using a bulk curing technique.
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Affiliation(s)
| | - Míriam Lacalle Turbino
- University of São Paulo, School of Dentistry, Restorative Dentistry, São Paulo, São Paulo, Brazil.
| | - Marcelo Giannini
- University of Campinas, Piracicaba Dental School, Restorative Dentistry, Piracicaba, São Paulo, Brazil.
| | - Roberto Ruggiero Braga
- University of São Paulo, School of Dentistry, Biomaterials and Oral Biology, São Paulo, São Paulo, Brazil.
| | - Richard Bengt Price
- Dalhousie University, Faculty of Dentistry, Dental Clinical Sciences, 5981 University Ave., Halifax, Nova Scotia, B3H 4R2, Canada.
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Guidelines for the selection, use, and maintenance of LED light-curing units - Part 1. Br Dent J 2018; 221:453-460. [PMID: 27767163 DOI: 10.1038/sj.bdj.2016.772] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2016] [Indexed: 11/08/2022]
Abstract
Light curing is a critical step in the restorative process when using light-activated resin-based composites, but it is frequently not given the attention it deserves. The selection of a reliable light curing unit (LCU) that meets the practitioner's needs is an important equipment purchase. Using an inappropriate LCU may seriously compromise the quality of care without the practitioner realising their mistake until years later. The importance of the subject is reflected by the rapidly increasing use of light-cured composites and the decline in the use of amalgam. Many changes have occurred in the equipment and materials available for making light-cured restorations in the last twenty years. This article is part of a two-part series that will describe those changes and recommend guidelines for the selection, use, and maintenance of light emitting diode light-curing units (LED LCUs). This paper (Part 1) discusses terminology, clinical studies, the development of LCUs in dentistry, the aims of light-curing, and the need to deliver an adequate amount of energy. The interaction between light source and material is briefly described to demonstrate the complex nature of the resin photopolymerisation process.
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Abstract
The ability to light cure resins 'on demand' in the mouth has revolutionized dentistry. However, there is a widespread lack of understanding of what is required for successful light curing in the mouth. Most instructions simply tell the user to 'light cure for xx seconds' without describing any of the nuances of how to successfully light cure a resin. This article provides a brief description of light curing. At the end, some recommendations are made to help when purchasing a curing light and how to improve the use of the curing light.
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Affiliation(s)
- Richard B T Price
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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Shimokawa C, Sullivan B, Turbino ML, Soares CJ, Price RB. Influence of Emission Spectrum and Irradiance on Light Curing of Resin-Based Composites. Oper Dent 2017; 42:537-547. [PMID: 28581917 DOI: 10.2341/16-349-l] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE This study examined the influence of different emission spectra (single-peak and broad-spectrum) light-curing units (LCUs) delivering the same radiant exposures at irradiance values of 1200 or 3600 mW/cm2 on the polymerization and light transmission of four resin-based composites (RBCs). METHODS AND MATERIALS Two prototype LCUs that used the same light tip, but were either a single-peak blue or a broad-spectrum LED, were used to deliver the same radiant exposures to the top surfaces of the RBCs using either standard (1200 mW/cm2) or high irradiance (3600 mW/cm2) settings. The emission spectrum and radiant power from the LCUs were measured with a laboratory-grade integrating sphere coupled to a spectrometer, and the light beam was assessed with a beam profiler camera. Four RBCs (Filtek Supreme Ultra A2, Tetric EvoCeram A2, Tetric EvoCeram T, and TPH Spectra High Viscosity A2) were photoactivated using four different light conditions: single-peak blue/standard irradiance, single-peak blue/high irradiance, broad-spectrum/standard irradiance, and broad-spectrum/high irradiance. The degree of conversion (N=5) and microhardness at the top and bottom of 2.3-mm-diameter by 2.5-mm-thick specimens (N=5) were analyzed with analysis of variance and Tukey tests. The real-time light transmission through the RBCs was also measured. RESULTS For all light conditions, the 2.3-mm-diameter specimens received a homogeneous irradiance and spectral distribution. Although similar radiant exposures were delivered to the top surfaces of the RBCs, the amount of light energy emitted from the bottom surfaces was different among the four RBCs, and was also greater for the single-peak lights. Very little violet light (wavelengths below 420 nm) reached the bottom of the 2.5-mm-thick specimens. The degree of conversion and microhardness results varied according to the RBC (p<0.05). The RBCs that included alternative photoinitiators had greater microhardness values at the top when cured with broad-spectrum lights, while at the bottom, where little violet light was observed, the results were equal or higher when they were photoactivated with single-peak blue lights. With the exception of the microhardness at the top of TPH, equivalent or higher microhardness and degree-of-conversion values were achieved at the bottom surface when the standard (1200 mW/cm2) irradiance levels were used compared to when high irradiance levels were used. CONCLUSIONS Considering the different behaviors of the tested RBCs, the emission spectrum and irradiance level influenced the polymerization of some RBCs. The RBCs that included alternative photoinitiators produced greater values at the top when cured with broad-spectrum lights, while at the bottom, results were equal or higher for the RBCs photoactivated with single-peak blue lights.
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Jang Y, Ferracane JL, Pfeifer CS, Park JW, Shin Y, Roh BD. Effect of Insufficient Light Exposure on Polymerization Kinetics of Conventional and Self-adhesive Dual-cure Resin Cements. Oper Dent 2017; 42:E1-E9. [DOI: 10.2341/15-278-l] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Objectives: The purpose of this study was to investigate the influence of insufficient light exposure on the polymerization of conventional and self-adhesive dual-cure resin cements under ceramic restorations.
Methods: Two conventional dual-cure resin cements (Rely-X ARC, Duolink) and two self-adhesive resin cements (Rely-X U200, Maxcem Elite) were polymerized under different curing modes (dual-cure or self-cure), curing times (20 and 120 seconds), and thickness of a ceramic overlay (2 and 4 mm). Polymerization kinetics was measured by Fourier transform infrared spectroscopy for the initial 10 minutes and after 24 hours. Data were analyzed using mixed model analysis of variance (ANOVA), one-way ANOVA/Student-Newman-Keuls post hoc test, and paired t-test (α=0.05).
Results: When light-curing time was set to 20 seconds, the presence of the ceramic block significantly affected the degree of conversion (DC) of all resin cements. Especially, the DC of the groups with 20 seconds of light-curing time under 4 mm of ceramic thickness was even lower than that of the self-cured groups at 24 hours after polymerization (p<0.05). However, when light-curing time was set to 120 seconds, a similar DC compared with the group with direct light exposure (p>0.05) was achieved in all dual-cure groups except Maxcem Elite, at 24 hours after polymerization.
Conclusions: For both conventional and self-adhesive dual-cure resin cements, insufficient light exposure (20 seconds of light-curing time) through thick ceramic restoration (4 mm thick) resulted in a DC even lower than that of self-curing alone.
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Affiliation(s)
- Y Jang
- Youngjune Jang, DDS, PhD, Yonsei University, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Seoul, Republic of Korea
| | - JL Ferracane
- Jack L Ferracane, PhD, Oregon Health & Science University, Restorative Dentistry, Portland, OR, USA
| | - CS Pfeifer
- Carmem Silvia Pfeifer, DDS, PhD, Oregon Health & Science University, Restorative Dentistry, Portland, OR, USA
| | - JW Park
- Jeong-Won Park, DDS, MSD, PhD, Yonsei University, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Gangnam Severance Hospital, Seoul, Republic of Korea
| | - Y Shin
- Yooseok Shin, DDS, MSD, PhD, Yonsei University, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Seoul, Republic of Korea
| | - BD Roh
- Byoung-Duck Roh, DDS, MSD, PhD, Yonsei University, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Seoul, Republic of Korea
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Effect of High-Irradiance Light-Curing on Micromechanical Properties of Resin Cements. BIOMED RESEARCH INTERNATIONAL 2016; 2016:4894653. [PMID: 28044129 PMCID: PMC5164896 DOI: 10.1155/2016/4894653] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/11/2016] [Accepted: 11/17/2016] [Indexed: 11/24/2022]
Abstract
This study investigated the influence of light-curing at high irradiances on micromechanical properties of resin cements. Three dual-curing resin cements and a light-curing flowable resin composite were light-cured with an LED curing unit in Standard mode (SM), High Power mode (HPM), or Xtra Power mode (XPM). Maximum irradiances were determined using a MARC PS radiometer, and exposure duration was varied to obtain two or three levels of radiant exposure (SM: 13.2 and 27.2 J/cm2; HPM: 15.0 and 30.4 J/cm2; XPM: 9.5, 19.3, and 29.7 J/cm2) (n = 17). Vickers hardness (HV) and indentation modulus (EIT) were measured at 15 min and 1 week. Data were analyzed with nonparametric ANOVA, Wilcoxon-Mann-Whitney tests, and Spearman correlation analyses (α = 0.05). Irradiation protocol, resin-based material, and storage time and all interactions influenced HV and EIT significantly (p ≤ 0.0001). Statistically significant correlations between radiant exposure and HV or EIT were found, indicating that high-irradiance light-curing has no detrimental effect on the polymerization of resin-based materials (p ≤ 0.0021). However, one resin cement was sensitive to the combination of irradiance and exposure duration, with high-irradiance light-curing resulting in a 20% drop in micromechanical properties. The results highlight the importance of manufacturers issuing specific recommendations for the light-curing procedure of each resin cement.
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Gonulol N, Ozer S, Tunc ES. Effect of a third-generation LED LCU on microhardness of tooth-colored restorative materials. Int J Paediatr Dent 2016; 26:376-82. [PMID: 26548449 DOI: 10.1111/ipd.12213] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To assess the effects of different modes of a third-generation light-curing unit (LCU) (VALO) on the microhardness of restorative materials. DESIGN A microhybrid composite resin (Filtek(™) Z550), a giomer (Beautifil II), a compomer (Dyract eXtra) and a RMGIC (Photac(™) Fil) were used in the study. Three different modes of VALO were tested and a second-generation LCU (Elipar S10) was used as a control. The microhardness (VHN) was measured using a Vickers Hardness tester. Data were analyzed using two-way anova and post hoc Tukey's test (P < 0.05). RESULTS The Filtek Z550 group had the highest VHN values followed by Photac Fil, Beautifil II and the Dyract eXtra at both top and bottom surfaces, however the difference between Filtek Z550 and Photac Fil was not statistically significant for the bottom surfaces (P > 0.05). Of the different curing protocols tested, the VALO LCU in Mode 3 resulted in the lowest VHN values at both top and bottom surfaces (P < 0.05). CONCLUSION Based on the results of this study, it can be concluded that the high-power mode of the VALO LCU can be recommended for clinical applications especially in pediatric patients, as it can shorten the time required to adequately polymerize resin-based tooth-colored restorative materials.
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Affiliation(s)
- Nihan Gonulol
- Department of Restorative Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey
| | - Sezin Ozer
- Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey
| | - Emine Sen Tunc
- Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey
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Study of energy transfer by different light curing units into a class III restoration as a function of tilt angle and distance, using a MARC Patient Simulator (PS). Dent Mater 2016; 32:676-86. [DOI: 10.1016/j.dental.2016.02.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/23/2016] [Accepted: 02/24/2016] [Indexed: 11/24/2022]
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Pereira AG, Raposo L, Teixeira D, Gonzaga R, Cardoso IO, Soares CJ, Soares PV. Influence of Battery Level of a Cordless LED Unit on the Properties of a Nanofilled Composite Resin. Oper Dent 2016; 41:409-16. [PMID: 26919084 DOI: 10.2341/15-200-l] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The properties of composite resins can be influenced by light activation, depending primarily on the performance of the curing unit. The aim of this study was to evaluate how different battery levels of a cordless light-emitting diode (LED) unit influence the properties of a nanofilled composite resin. First, the battery voltage and light intensity of the cordless LED unit were individually checked for all light-curing cycles. Then, composite resin discs were prepared and light-cured at different battery levels: high level (HL, 100%), medium level (ML, 50%), and low level (LL, 10%). The degree of conversion, diametral tensile strength, sorption, and solubility of the specimens were tested. Data were checked for homoscedasticity and submitted to one-way analysis of variance followed by Tukey honestly significant difference and Pearson correlation tests (p<0.05). The battery voltage and light intensity varied significantly among the groups (p<0.001). The LL group presented a lower degree of conversion than the HL and ML groups (p<0.001), which shower similar results (p=0.182). Lower diametral tensile strength was also verified for the LL group when compared with the HL and ML groups (p<0.001), which presented no difference (p=0.052). Positive correlation was observed between the light intensity and the parameters studied, with the exception of sorption and solubility (p<0.001). The ML and LL groups showed higher sorption than the HL group (p <0.001), but no difference was verified between the first two groups (p=0.535). No significant differences were found for solubility between the ML and LL groups (p=0.104), but the HL group presented lower values (p<0.001). The different battery levels of the cordless LED curing unit influenced all the properties of the nanofilled composite resin evaluated.
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Selig D, Haenel T, Hausnerová B, Moeginger B, Labrie D, Sullivan B, Price RBT. Examining exposure reciprocity in a resin based composite using high irradiance levels and real-time degree of conversion values. Dent Mater 2015; 31:583-93. [PMID: 25804190 DOI: 10.1016/j.dental.2015.02.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 12/10/2014] [Accepted: 02/16/2015] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Exposure reciprocity suggests that, as long as the same radiant exposure is delivered, different combinations of irradiance and exposure time will achieve the same degree of resin polymerization. This study examined the validity of exposure reciprocity using real time degree of conversion results from one commercial flowable dental resin. Additionally a new fitting function to describe the polymerization kinetics is proposed. METHODS A Plasma Arc Light Curing Unit (LCU) was used to deliver 0.75, 1.2, 1.5, 3.7 or 7.5 W/cm(2) to 2mm thick samples of Tetric EvoFlow (Ivoclar Vivadent). The irradiances and radiant exposures received by the resin were determined using an integrating sphere connected to a fiber-optic spectrometer. The degree of conversion (DC) was recorded at a rate of 8.5 measurements a second at the bottom of the resin using attenuated total reflectance Fourier Transform mid-infrared spectroscopy (FT-MIR). Five specimens were exposed at each irradiance level. The DC reached after 170s and after 5, 10 and 15 J/cm(2) had been delivered was compared using analysis of variance and Fisher's PLSD post hoc multiple comparison tests (alpha=0.05). RESULTS The same DC values were not reached after the same radiant exposures of 5, 10 and 15 J/cm(2) had been delivered at an irradiance of 3.7 and 7.5 W/cm(2). Thus exposure reciprocity was not supported for Tetric EvoFlow (p<0.05). SIGNIFICANCE For Tetric EvoFlow, there was no significant difference in the DC when 5, 10 and 15J/cm(2) were delivered at irradiance levels of 0.75, 1.2 and 1.5 W/cm(2). The optimum combination of irradiance and exposure time for this commercial dental resin may be close to 1.5 W/cm(2) for 12s.
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Affiliation(s)
- Daniela Selig
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada; Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany; FH Aachen University of Applied Sciences, Department of Natural Sciences, Jülich, Germany
| | - Thomas Haenel
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada; Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany; Tomas Bata University in Zlin, Faculty of Technology, Department of Production Engineering, Zlin, Czech Republic; Tomas Bata University in Zlin, University Institute, Centre of Polymer Systems, Zlin, Czech Republic
| | - Berenika Hausnerová
- Tomas Bata University in Zlin, Faculty of Technology, Department of Production Engineering, Zlin, Czech Republic; Tomas Bata University in Zlin, University Institute, Centre of Polymer Systems, Zlin, Czech Republic
| | - Bernhard Moeginger
- Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany
| | - Daniel Labrie
- Dalhousie University, Department of Physics and Atmospheric Sciences, Halifax, Canada
| | - Braden Sullivan
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada
| | - Richard B T Price
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada.
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Haenel T, Hausnerová B, Steinhaus J, Price RBT, Sullivan B, Moeginger B. Effect of the irradiance distribution from light curing units on the local micro-hardness of the surface of dental resins. Dent Mater 2014; 31:93-104. [PMID: 25483935 DOI: 10.1016/j.dental.2014.11.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 07/10/2014] [Accepted: 11/03/2014] [Indexed: 11/27/2022]
Abstract
OBJECTIVE An inhomogeneous irradiance distribution from a light-curing unit (LCU) can locally cause inhomogeneous curing with locally inadequately cured and/or over-cured areas causing e.g. monomer elution or internal shrinkage stresses, and thus reduce the lifetime of dental resin based composite (RBC) restorations. The aim of the study is to determine both the irradiance distribution of two light curing units (LCUs) and its influence on the local mechanical properties of a RBC. METHODS Specimens of Arabesk TOP OA2 were irradiated for 5, 20, and 80s using a Bluephase® 20i LCU in the Low mode (666mW/cm(2)), in the Turbo mode (2222mW/cm(2)) and a Celalux® 2 (1264mW/cm(2)). The degree of conversion (DC) was determined with an ATR-FTIR. The Knoop micro-hardness (average of five specimens) was measured on the specimen surface after 24h of dark and dry storage at room temperature. RESULTS The irradiance distribution affected the hardness distribution across the surface of the specimens. The hardness distribution corresponded well to the inhomogeneous irradiance distributions of the LCU. The highest reaction rates occurred after approximately 2s light exposure. A DC of 40% was reached after 3.6 or 5.7s, depending on the LCU. The inhomogeneous hardness distribution was still evident after 80s of light exposure. SIGNIFICANCE The irradiance distribution from a LCU is reflected in the hardness distribution across the surface. Irradiance level of the LCU and light exposure time do not affect the pattern of the hardness distribution--only the hardness level. In areas of low irradiation this may result in inadequate resin polymerization, poor physical properties, and hence premature failure of the restorations as they are usually much smaller than the investigated specimens. It has to be stressed that inhomogeneous does not necessarily mean poor if in all areas of the restoration enough light intensity is introduced to achieve a high degree of cure.
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Affiliation(s)
- Thomas Haenel
- Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Zlin, Czech Republic; Bonn-Rhein-Sieg, University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany
| | - Berenika Hausnerová
- Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Zlin, Czech Republic; Tomas Bata University in Zlin, Faculty of Technology, Department of Production Engineering, Zlin, Czech Republic
| | - Johannes Steinhaus
- Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Zlin, Czech Republic; Bonn-Rhein-Sieg, University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany
| | - Richard B T Price
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada
| | - Braden Sullivan
- Dalhousie University, Department of Dental Clinical Sciences, Faculty of Dentistry, Halifax, Canada
| | - Bernhard Moeginger
- Bonn-Rhein-Sieg, University of Applied Sciences, Department of Natural Sciences, Rheinbach, Germany.
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Zingler S, Matthei B, Kohl A, Saure D, Ludwig B, Diercke K, Lux CJ, Erber R. In vitro studies on the cytotoxic potential of surface sealants. J Orofac Orthop 2014; 76:66-78. [PMID: 25420945 DOI: 10.1007/s00056-014-0269-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/23/2014] [Indexed: 11/24/2022]
Abstract
OBJECTIVE The objective of this in vitro study was an initial screening of the cytotoxic potential of widely used smooth enamel surface sealants. MATERIALS AND METHODS A total of 20 products were allocated to four groups based on their chemical composition: (1) filled resin-based sealants, (2) unfilled resin-based sealants, (3) a resin-modified, glass ionomer-based sealant, and (4) silicone-based sealants. All materials were applied to human enamel slices both in accordance with manufacturers' instructions and in additional experiments applying 50% undercuring and 50% overcuring. An agar overlay assay was then used to test the specimens following ISO 10933. The cytotoxic potential of each material was interpreted based on a reaction index that summarized the decolorization and lysis scores obtained. RESULTS The cytotoxic potential decreased as follows: unfilled resin-based sealants > filled resin-based sealants > resin-modified, glass ionomer-based sealant > silicone-based sealants. In 75% of the resin-based products, deliberate undercuring was associated with more extensive decolorization zones, leading to higher rates of cytotoxic potential in two of those products. Overcuring, by contrast, was associated with a tendency for smaller decolorization zones in 50% of the resin-based products. CONCLUSION Surface sealants derived from resin monomers exhibited cytotoxic potential in the agar overlay assay. There is also evidence of a possible association with curing, as undercuring can increase the cytotoxic potential, whereas normal curing (as per manufacturers' instructions) or overcuring may help minimize such effects. More research into the biological implications of these materials is needed, especially with regard to their potential impact on the adjacent gingiva.
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Affiliation(s)
- S Zingler
- Department of Orthodontics, University of Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany,
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Zingler S, Matthei B, Diercke K, Frese C, Ludwig B, Kohl A, Lux CJ, Erber R. Biological evaluation of enamel sealants in an organotypic model of the human gingiva. Dent Mater 2014; 30:1039-51. [PMID: 24993810 DOI: 10.1016/j.dental.2014.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 04/03/2014] [Accepted: 06/05/2014] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Various sealant materials have been suggested to decrease decalcification during orthodontic treatment. However, only a few in vitro studies on the cytotoxicity of resinous pit and fissure sealants have been published, and to the best of our knowledge no similar studies are available for the enamel sealants used in orthodontics. Therefore, we aimed to characterize the possible adverse effects of enamel sealants, especially on the gingival epithelium. METHODS Organotypic cultures of the human gingival mucosa were used to assess the possible impact of six enamel sealants. Differentiation and apoptosis were determined by immunofluorescent staining. The pro-inflammatory cytokines IL-1β and IL-6 were quantified by ELISA. Cytotoxicity was measured using MTS assays in monolayer cultures of human gingival fibroblasts. Leaching of monomers from enamel sealants was quantified using HPLC. RESULTS The differentiation of the organotypic gingival mucosa remained unaffected. All under-cured and several standard-cured sealants (Light Bond™ Sealant, Light Bond™ Filled Sealant, and L.E.D. Pro Seal®) significantly induced apoptosis in the organotypic model. Light Bond™ Sealant, Light Bond™ Filled Sealant, and L.E.D. Pro Seal® caused a significant induction of pro-inflammatory cytokines. Reducing curing time had an influence on cytotoxicity in monolayer cultures of primary human oral cells. All resin-based sealants leached monomers. SIGNIFICANCE Enamel sealants might exert adverse effects on the gingival epithelium. Due to the vicinity of the enamel sealant to the gingival epithelium, and the large surface area of applied sealants, these materials should be carefully applied and sufficiently cured.
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Affiliation(s)
- Sebastian Zingler
- Department of Orthodontics and Dentofacial Orthopedics, Dental School, University of Heidelberg, Heidelberg, Germany
| | - Byron Matthei
- Department of Orthodontics and Dentofacial Orthopedics, Dental School, University of Heidelberg, Heidelberg, Germany
| | - Katja Diercke
- Department of Orthodontics and Dentofacial Orthopedics, Dental School, University of Heidelberg, Heidelberg, Germany
| | - Cornelia Frese
- Department of Conservative Dentistry, Dental School, University of Heidelberg, Heidelberg, Germany
| | - Björn Ludwig
- Department of Orthodontics and Dentofacial Orthopedics, Dental School, University of Heidelberg, Heidelberg, Germany; Private Practice, Traben-Trarbach, Germany
| | - Annette Kohl
- Department of Orthodontics and Dentofacial Orthopedics, Dental School, University of Heidelberg, Heidelberg, Germany
| | - Christopher J Lux
- Department of Orthodontics and Dentofacial Orthopedics, Dental School, University of Heidelberg, Heidelberg, Germany
| | - Ralf Erber
- Department of Orthodontics and Dentofacial Orthopedics, Dental School, University of Heidelberg, Heidelberg, Germany.
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Erickson RL, Barkmeier WW, Halvorson RH. Curing characteristics of a composite – Part 1: Cure depth relationship to conversion, hardness and radiant exposure. Dent Mater 2014; 30:e125-33. [DOI: 10.1016/j.dental.2014.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 11/20/2013] [Accepted: 02/13/2014] [Indexed: 10/25/2022]
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Wegehaupt FJ, Tauböck TT, Attin T, Belibasakis GN. Influence of light-curing mode on the cytotoxicity of resin-based surface sealants. BMC Oral Health 2014; 14:48. [PMID: 24885810 PMCID: PMC4019812 DOI: 10.1186/1472-6831-14-48] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 05/01/2014] [Indexed: 11/10/2022] Open
Abstract
Background Surface sealants have been successfully used in the prevention of erosive tooth wear. However, when multiple tooth surfaces should be sealed, the light-curing procedure is very time-consuming. Therefore, the aim of this study was to investigate whether reduced light-curing time (while maintaining similar energy density) has an influence on resin-based surface sealant cytotoxicity. Methods Bovine dentine discs were treated as follows: group 1: untreated, groups 2–5: Seal&Protect and groups 6–9: experimental sealer. Groups 2 and 6 were light-cured (VALO LED light-curing device) for 40 s (1000 mW/cm2), groups 3 and 7 for 10 s (1000 mW/cm2), groups 4 and 8 for 7 s (1400 mW/cm2) and groups 5 and 9 for 3 s (3200 mW/cm2). Later, materials were extracted in culture medium for 24 h, and released lactate dehydrogenase (LDH) activity as a measure of cytotoxicity was determined photometrically after cells (dental pulp cells and gingival fibroblasts) were exposed to the extracts for 24 h. Three independent experiments, for both sample preparation and cytotoxicity testing, were performed. Results Overall, lowest cytotoxicity was observed for the unsealed control group. No significant influence of light-curing settings on the cytotoxicity was observed (p = 0.537 and 0.838 for pulp cells and gingival fibroblasts, respectively). No significant difference in the cytotoxicity of the two sealants was observed after light-curing with same light-curing settings (group 2 vs. 6, 3 vs. 7, 4 vs. 8 and 5 vs. 9: p > 0.05, respectively). Conclusions Shortening the light-curing time, while maintaining constant energy density, resulted in no higher cytotoxicity of the investigated sealants.
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Affiliation(s)
- Florian J Wegehaupt
- Clinic for Preventive Dentistry, Periodontology and Cariology, University of Zurich, Plattenstrasse 11, 8032 Zürich, Switzerland.
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Influence of light-activation protocol on methacrylate resin-composite evaluated by dynamic mechanical analysis and degree of conversion. Lasers Med Sci 2014; 30:1219-23. [PMID: 24740520 DOI: 10.1007/s10103-014-1572-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 03/30/2014] [Indexed: 10/25/2022]
Abstract
The aim of this study was to evaluate the degree of conversion (DC) and to identify the viscoelastic properties: storage modulus (E'), loss modulus (E"), tangent delta (tan δ), and glass transition temperature (T g ) of a microhybrid resin-composite light-activated by three different protocols. A Filtek Z250 (3 M ESPE) shade A3 was inserted in a Teflon mold (21 mm × 5 mm × 1 mm for viscoelastic properties; and 5 mm × 1 mm for DC) and light-activated according to the following light-activation protocols: (S) 1,000 mW/cm(2) × 19 s, (HP) 1,400 mW/cm(2) × 14 s, and (PE) 3,200 mW/cm(2) × 6 s, all set up to deliver 19 J/cm(2). Viscoelastic properties was assessed by dynamic mechanical analysis (DMA) (n = 3), performed in single cantilever clamped mode. DC (n = 5) was measured by FTIR on top (T) and bottom (B) surfaces, and the data was submitted to a split-plot one-way ANOVA. For DC, there was a significant effect for surface factor and light-activation protocols factor. Top surface showed higher DC than B in all experimental conditions. Light-activation protocols S and HP resulted in higher DC than PE and were similar between them. Viscoelastic properties (E', E", tan δ, T g ) were not affected by light-activation protocols. It could be concluded that light-activation protocols influenced DC but not influenced the viscoelastic properties.
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Bortolotto T, Dagon C, Krejci I. Light polymerization during cavity filling: effect of 'exposure reciprocity law' and the resulted shrinkage forces on restoration margins. Acta Odontol Scand 2013; 71:1296-302. [PMID: 23796309 DOI: 10.3109/00016357.2012.762988] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To evaluate shrinkage development and marginal integrity of a micro hybrid restorative composite as a function of irradiance. MATERIALS AND METHODS Linear displacement and shrinkage were measured with custom-made devices for irradiances of 100, 200, 400, 800 and 1600 mW/cm(2) at a constant radiant exposure of 16 J/cm(2). Marginal adaptation (MA) of composite restorations performed with a self-etch adhesive (Syntac Classic, Ivoclar Vivadent) and a micro hybrid composite (Tetric, Ivoclar Vivadent) was evaluated before and after mechanical loading with 300,000 cycles at 70 N. RESULTS The highest percentage of MA was attained by the group light cured with an irradiance of 100 mW/cm(2) for 160 s. No significant differences were observed between the rest of the groups. Shrinkage development was similar in all groups. CONCLUSIONS For the material tested in this study, the reciprocal relationship between irradiance and time of exposure had no significant effect on restoration margins and shrinkage stress development within the range of 200-1600 mW/cm(2) with a constant radiant exposure of 16 J/cm(2).
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Affiliation(s)
- Tissiana Bortolotto
- Division of Cariology and Endodontics, School of Dental Medicine, University of Geneva , Switzerland.
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Light polymerization during cavity filling: influence of total energy density on shrinkage and marginal adaptation. Odontology 2013; 102:184-8. [DOI: 10.1007/s10266-013-0123-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 06/02/2013] [Indexed: 10/26/2022]
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Abstract
This review article will help clinicians understand the important role of the light curing unit (LCU) in their offices. The importance of irradiance uniformity, spectral emission, monitoring the LCU, infection control methods, recommended light exposure times, and learning the correct light curing technique are reviewed. Additionally, the consequences of delivering too little or too much light energy, the concern over leachates from undercured resins, and the ocular hazards are discussed. Practical recommendations are provided to help clinicians improve their use of the LCU so that their patients can receive safe and potentially longer lasting resin restorations.
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A survey of power density of light-curing units used in private dental offices in Changchun City, China. Lasers Med Sci 2013; 30:493-7. [PMID: 23700081 DOI: 10.1007/s10103-013-1351-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 05/13/2013] [Indexed: 10/26/2022]
Abstract
This study investigated power density and relevant information related to light-curing units used in private dental offices in Changchun City, China. The power density of 196 light-curing units used in private dental offices in Changchun City was measured using a simple random sampling method. Relevant information included the brand, type, years of operation, frequency of use, model numbers and types of light guide, resin buildup on the light guides, damage caused by the light guides, required maintenance of the curing lights, and ratio of the unit and chair number. There were 132 quartz tungsten halogen (QTH) units and 64 light-emitting diode units. The power density range was defined as 0-1,730 mW/cm(2). The mean power density was 453.1 mW/cm(2). The mean years of operation of the light-curing units were 3.96. The majority of dentists never tested the power density of the light-curing units and a considerable number of light guide surfaces showed resin buildup and damage. In Changchun City, the majority of light-curing units were QTH. Some units needed to be replaced due to aging. The majority of dentists were not aware that the light-curing units require periodic testing and maintenance. The data herein indicate the importance of periodic testing of the power density of light-curing units and timely replacement of the components and then guarantee the quality of medical services and their benefits to patients.
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Shortall A, El-Mahy W, Stewardson D, Addison O, Palin W. Initial fracture resistance and curing temperature rise of ten contemporary resin-based composites with increasing radiant exposure. J Dent 2013; 41:455-63. [DOI: 10.1016/j.jdent.2013.02.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 02/01/2013] [Accepted: 02/02/2013] [Indexed: 10/27/2022] Open
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Passos SP, Souza ROA, Michida SMA, Zamboni SC, Oliveira SHGD. Effects of cement-curing mode and light-curing unit on the bond durability of ceramic cemented to dentin. Braz Oral Res 2013; 27:169-75. [DOI: 10.1590/s1806-83242013005000005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 12/21/2012] [Indexed: 11/22/2022] Open
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Leprince JG, Palin WM, Hadis MA, Devaux J, Leloup G. Progress in dimethacrylate-based dental composite technology and curing efficiency. Dent Mater 2013. [PMID: 23199807 DOI: 10.1016/j.dental.2012.11.005] [Citation(s) in RCA: 324] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Julian G Leprince
- School of Dentistry and Stomatology, Université catholique de Louvain, Brussels, Belgium.
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