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Chou YC, Chuang SF, Lin JC, Li CL, Liu BY, Lee CL. Application of near-infrared-to-blue upconversion luminescence for the polymerization of resin cements through zirconia discs. Dent Mater 2024; 40:1208-1215. [PMID: 38851964 DOI: 10.1016/j.dental.2024.06.005] [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: 01/18/2024] [Revised: 06/02/2024] [Accepted: 06/03/2024] [Indexed: 06/10/2024]
Abstract
OBJECTIVES To investigate a near-infrared-to-blue luminescence upconversion curing method for polymerizing resin cements under zirconia discs. METHODS Lava zirconia discs of different thicknesses (0.5-2.0 mm) were manufactured. First, the transmittances of the NIR and two blue lights (BLs) (LED and halogen lights) through these discs were measured. Second, NaYF4:Yb3+/Tm3+ upconversion phosphor (UP) powder was milled into 0.5-μm particle sizes. A light-curable resin cement VariolinkII base was chosen as the control (UP0), and an experimental cement (UP5) was prepared by adding 5 % UPs. These two cements were examined using multiphoton excitation microscopy for particle distribution. UP5 and UP0 were polymerized with or without zirconia shielding then subjected to a microhardness test. A multifold analysis was performed to examine the effects of zirconia thickness, curing protocols (pure BL or combined BL and NIR curing), and cement type. RESULTS The transmittance of NIR was superior to that of BL through zirconia discs of all thicknesses. UP particles were homogeneously distributed in UP5 and emitted blue luminescence under 980-nm NIR excitation. UP5 showed higher microhardness values than UP0 under any curing protocol or zirconia shielding condition. The combination of 20-s BL and 40-s NIR curing yielded the highest microhardness in uncovered UP5. However, combining 40-s BL and 20-s NIR curing surpassed the other groups when the zirconia discs were thicker than 0.5 mm. SIGNIFICANCE NIR exhibits higher transmission through zirconia than BL. UP particles work as strengthen fillers and photosensitizers in cements. NIR upconversion curing could be a new strategy for polymerizing resin cements under thick zirconia restorations.
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Affiliation(s)
- Yu-Cheng Chou
- School of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Stomatology, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Shu-Fen Chuang
- School of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Stomatology, National Cheng Kung University Hospital, Tainan, Taiwan.
| | - Jui-Che Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Chia-Ling Li
- School of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Bang-Yan Liu
- School of Dentistry and Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chung-Lin Lee
- Department of Stomatology, National Cheng Kung University Hospital, Tainan, Taiwan
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Alzahrani B, Alshabib A, Awliya W. Surface hardness and flexural strength of dual-cured bulk-fill restorative materials after solvent storage. BMC Oral Health 2023; 23:306. [PMID: 37208664 DOI: 10.1186/s12903-023-03047-2] [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: 03/25/2023] [Accepted: 05/15/2023] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND This study aimed to evaluate the surface hardness (VHN) and biaxial flexural strength (BFS) of dual-cured bulk-fill restorative materials after solvent storage. METHODS Two dual-cured bulk-fill composites (Surefil One® and Activa™ Bioactive), a light-cured bulk-fill composite (Filtek One Bulk-Fill) and a resin-modified glass ionomer (Fuji II LC) were investigated. Surefil One and Activa were used in the dual-cure mode, all materials were handled according to manufacturer's instructions. For VHN determination, 12 specimens were prepared from each material and measured after 1 h (baseline), 1 d, 7 d and 30 d of storage in either water or 75% ethanol-water. For BFS test, 120 specimens were prepared (n = 30/material) and stored in water for either 1, 7 or 30 d before testing. Repeated measures MANOVA, two-way and one-way ANOVA followed by the Tukey post hoc test (p ≤ 0.05) were used to analyze the data. RESULTS Filtek One had the highest VHN, while Activa had the lowest. All materials exhibited a significant increase in VHN after 1d of storage in water, except for Surefil One. After 30 d of storage, VHN increased significantly in water except for Activa, while ethanol storage caused a significant time-dependent reduction in all tested materials (p ≤ 0.05). Filtek One showed the highest BFS values (p ≤ 0.05). All the materials, except for Fuji II LC, exhibited no significant differences between 1 and 30 d BFS measurements (p > 0.05). CONCLUSIONS Dual-cured materials had significantly lower VHN and BFS compared to the light-cured bulk-fill material. The low results of Activa VHN and Surefil One BFS, indicate that these materials should not be recommended in posterior stress-bearing areas.
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Affiliation(s)
- Bashayer Alzahrani
- Department of Restorative Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
| | - Abdulrahman Alshabib
- Department of Restorative Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Wedad Awliya
- Department of Restorative Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
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Pieniak D, Niewczas AM, Pikuła K, Gil L, Krzyzak A, Przystupa K, Kordos P, Kochan O. Effect of Hydrothermal Factors on the Microhardness of Bulk-Fill and Nanohybrid Composites. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2130. [PMID: 36903245 PMCID: PMC10004216 DOI: 10.3390/ma16052130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/27/2023] [Accepted: 03/03/2023] [Indexed: 06/18/2023]
Abstract
This study evaluates the effect of aging in artificial saliva and thermal shocks on the microhardness of the bulk-fill composite compared to the nanohybrid composite. Two commercial composites, Filtek Z550 (3M ESPE) (Z550) and Filtek Bulk-Fill (3M ESPE) (B-F), were tested. The samples were exposed to artificial saliva (AS) for one month (control group). Then, 50% of the samples from each composite were subjected to thermal cycling (temperature range: 5-55 °C, cycle time: 30 s, number of cycles: 10,000) and another 50% were put back into the laboratory incubator for another 25 months of aging in artificial saliva. The samples' microhardness was measured using the Knoop method after each stage of conditioning (after 1 month, after 10,000 thermocycles, after another 25 months of aging). The two composites in the control group differed considerably in hardness (HK = 89 for Z550, HK = 61 for B-F). After thermocycling, the microhardness decrease was for Z550 approximately 22-24% and for B-F approximately 12-15%. Hardness after 26 months of aging decreased for Z550 (approximately 3-5%) and B-F (15-17%). B-F had a significantly lower initial hardness than Z550, but it showed an approximately 10% lower relative reduction in hardness.
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Affiliation(s)
- Daniel Pieniak
- Tribology Center, Łukasiewicz Research Network-Institute for Sustainable Technologies (L-ITEE), Ul. Pułaskiego 6/10, 26-600 Radom, Poland
- Faculty of Transport and Computer Science, WSEI University, Projektowa 4, 20-209 Lublin, Poland
| | - Agata M. Niewczas
- Department of Conservative Dentistry with Endodontics, Medical University of Lublin, W. Chodźki 6, 20-093 Lublin, Poland
| | - Konrad Pikuła
- Department of Conservative Dentistry with Endodontics, Medical University of Lublin, W. Chodźki 6, 20-093 Lublin, Poland
| | - Leszek Gil
- Faculty of Transport and Computer Science, WSEI University, Projektowa 4, 20-209 Lublin, Poland
| | - Aneta Krzyzak
- Faculty of Aeronautics, Military University of Aviation in Dęblin, 35 Dywizjonu 303, 08-521 Deblin, Poland
| | - Krzysztof Przystupa
- Department of Automation, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland
| | - Paweł Kordos
- Institute of Transport, Combustion Engines and Ecology, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland
| | - Orest Kochan
- School of Computer Science, Hubei University of Technology, Wuhan 430068, China
- Department of Measuring Information Technologies, Lviv Polytechnic National University, Bandery Str. 12, 79013 Lviv, Ukraine
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Daabash R, Alshabib A, Alqahtani MQ, Price RB, Silikas N, Alshaafi MM. Ion releasing direct restorative materials: Key mechanical properties and wear. Dent Mater 2022; 38:1866-1877. [DOI: 10.1016/j.dental.2022.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/18/2022] [Accepted: 09/22/2022] [Indexed: 11/15/2022]
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Piemjai M, Santiwarapan P. An Enamel Based Biopolymer Prosthesis for Dental Treatment with the Proper Bond Strength and Hardness and Biosafety. Polymers (Basel) 2022; 14:polym14030538. [PMID: 35160527 PMCID: PMC8839297 DOI: 10.3390/polym14030538] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 02/01/2023] Open
Abstract
Although dental prosthesis materials such as metal alloys, ceramics, and cured resin composite have long been utilized to restore teeth, their bond strength and hardness values are not well matched to human enamel. Prosthesis detachment and opposing enamel wear are major concerns in restorative dentistry. An experimental biopolymer, hybridized enamel, was synthesized and utilized as a dental prosthesis to compare hardness and tensile bond strength (TBS) with those of commercial materials. Vickers hardness (VHN) with a 100 g loading for 15 s at eight indentations on each specimen (n = 20) was measured. TBSs between prostheses and two types of resin luting agents (n = 10), Super-Bond C&B and All-Bond2 + Duo-Link, were tested. Fractured surfaces and the luting resin-prosthesis interface were examined under a stereomicroscope or a scanning electron microscope (SEM). Statistically significant differences in the TBS and hardness were revealed (p < 0.05). The experimental biopolymer provided a hardness value comparable with human enamel and the highest TBS for both luting agent types. The SEM micrograph demonstrated a honeycomb-like pattern interface between the experimental biopolymer and luting resin. These results suggest that this experimental biopolymer may be a better restorative material to protect from natural enamel loss from tooth reduction or attrition and prevent prosthesis detachment during mastication.
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Novel Polymerization of Dental Composites Using Near-Infrared-Induced Internal Upconversion Blue Luminescence. Polymers (Basel) 2021; 13:polym13244304. [PMID: 34960853 PMCID: PMC8704827 DOI: 10.3390/polym13244304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 11/17/2022] Open
Abstract
Blue light (BL) curing on dental resin composites results in gradient polymerization. By incorporating upconversion phosphors (UP) in resin composites, near-infrared (NIR) irradiation may activate internal blue emission and a polymerization reaction. This study was aimed to evaluate the competency of the NIR-to-BL upconversion luminance in polymerizing dental composites and to assess the appropriate UP content and curing protocol. NaYF4 (Yb3+/Tm3+ co-doped) powder exhibiting 476-nm blue emission under 980-nm NIR was adapted and ball-milled for 4–8 h to obtain different particles. The bare particles were assessed for their emission intensities, and also added into a base composite Z100 (3M EPSE) to evaluate their ability in enhancing polymerization under NIR irradiation. Experimental composites were prepared by dispensing the selected powder and Z100 at different ratios (0, 5, 10 wt% UP). These composites were irradiated under different protocols (BL, NIR, or their combinations), and the microhardness at the irradiated surface and different depths were determined. The results showed that unground UP (d50 = 1.9 μm) exhibited the highest luminescence, while the incorporation of 0.4-μm particles obtained the highest microhardness. The combined 20-s BL and 20–120-s NIR significantly increased the microhardness on the surface and internal depths compared to BL correspondents. The 5% UP effectively enhanced the microhardness under 80-s NIR irradiation but was surpassed by 10% UP with longer NIR irradiation. The combined BL-NIR curing could be an effective approach to polymerize dental composites, while the intensity of upconversion luminescence was related to specific UP particle size and content. Incorporation of 5–10% UP facilitates NIR upconversion polymerization on dental composites.
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A Comparative Study of the Mechanical Properties of Selected Dental Composites with a Dual-Curing System with Light-Curing Composites. COATINGS 2021. [DOI: 10.3390/coatings11101255] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Dual-curing composites have a wide spectrum of use in practice (rebuilding, reconstruction, and luting). The characterization of this type of material and comparative study of selected mechanical properties with light-cured materials were carried out for this paper. In this study, we used six materials with a dual-cure system—Bulk EZ, Fill-Up!, StarFill 2B, Rebilda DC, MultiCore Flow, Activa Bioactive-Restorative—and three light-cured materials—Filtek Bulk Fill Posterior, Charisma Classic, and G-aenial Universal Flo. The materials were conditioned for 24 h in water at 37 °C before testing. Selected material properties were determined: three-point bending flexural strength, diametral tensile strength, hardness, microhardness, and shrinkage stress. The highest three-point bending flexural strength (TPB) was 137.0 MPa (G-aenial Universal Flo), while the lowest amounted to 86.5 MPa (Activa Bioactive). The diametral tensile strength (DTS) values were in a range from 39.2 MPa (Rebilda DC) to 54.1 MPa (Charisma Classic). The lowest hardness (HV) value of 26 was obtained by the Activa Bioactive material, while the highest values were recorded for Filtek Bulk Fill Posterior and Charisma Classic-53. The shrinkage stress of the tested materials ranged from 6.3 MPa (Charisma Classic) to 13.2 MPa (G-aenial Universal Flo). Dual-curing composites were found to have similar properties to light-cured composites.
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Yoon S, Jung HJ, Knowles JC, Lee HH. Digital image correlation in dental materials and related research: A review. Dent Mater 2021; 37:758-771. [PMID: 33715864 DOI: 10.1016/j.dental.2021.02.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Digital image correlation (DIC) is a non-contact image processing technique for full-field strain measurement. Although DIC has been widely used in engineering and biomechanical fields, it is in the spotlight only recently in dental materials. Therefore, the purpose of this review paper is introducing the working principle of the DIC technique with some modifications and providing further potential applications in various dental materials and related fields. METHODS The accuracy of the algorithm depending on the environmental characteristics of the DIC technique, as well as the advantages and disadvantages of strain measurement using optical measurements, have been elaborated in dental materials and related fields. Applications to those researches have been classified into the following categories: shrinkage behavior of light-cured resin composite, resin-tooth interface, mechanical properties of tooth structure, crack extension and elastic properties of dental materials, and deformation of dental restoration and prosthesis. This classification and discussion were performed using literature survey and review based on numerous papers in the international journals published over the past 20 years. The future directions for predicting the precise deformation of dental materials under various environments, as well as limitations of the DIC technique, was presented in this review. RESULTS The DIC technique was demonstrated as a more effective tool to measure full-field polymerization shrinkage of composite resin, even in a simulated clinical condition over the existing methods. Moreover, the DIC combined with other technologies can be useful to evaluate the mechanical behavior of material-tooth interface, dentine structure and restorative and prosthetic materials with high accuracy. Three-dimensional DIC using two cameras extended the measurement range in-plane to out-of-plane, enabling measure of the strain directly on the surface of dental restorations or prosthesis. SIGNIFICANCE DIC technique is a potential tool for measuring and predicting the full-field deformation/strain of dental materials and actual prostheses in diverse clinical conditions. The versatility of DIC can replace the existing complex sensor devices in those studies.
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Affiliation(s)
- Sungsik Yoon
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hyung-Jo Jung
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - J C Knowles
- UCL Eastman-Korea Dental Medicine Innovation Centre, Dankook University, 119 Dandaero, Cheonan, Chungnam 31116, Republic of Korea; Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, London, UK
| | - Hae-Hyoung Lee
- Department of Biomaterials Science, College of Dentistry, Dankook University, 119 Dandaero, Cheonan, Chungnam 31116, Republic of Korea; Institute of Tissue Regeneration Engineering, Dankook University, 119 Dandaero, Cheonan, Chungnam 31116, Republic of Korea.
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Misinterpretation of ISO 4049 standard recommendations: Impact on Young's modulus and conversion degree of dental composites. J Mech Behav Biomed Mater 2020; 110:103947. [DOI: 10.1016/j.jmbbm.2020.103947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 06/16/2020] [Accepted: 06/21/2020] [Indexed: 11/19/2022]
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Ruengrungsom C, Burrow MF, Parashos P, Palamara JEA. Evaluation of F, Ca, and P release and microhardness of eleven ion-leaching restorative materials and the recharge efficacy using a new Ca/P containing fluoride varnish. J Dent 2020; 102:103474. [PMID: 32941973 DOI: 10.1016/j.jdent.2020.103474] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 09/04/2020] [Accepted: 09/10/2020] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVES The objectives of this study were to evaluate fluoride (F), calcium (Ca), and phosphate (P) release of ion-leaching restorative materials (ILMs), their recharge efficacy with a Ca/P-containing F varnish, and relative microhardness. METHODS Thirteen groups of materials were investigated. Cylindrical-shaped specimens were fabricated. Deionised water or lactic-acid solution were used as the storage media. Solutions were changed after 1d, 4d, 7d, and 14d of ion release and at the same periods after recharge with MI Varnish (7 -h storage). F, Ca, and P measurements were accomplished using a fluoride-ion selective electrode, atomic absorption spectrometry, and colourimetric method by spectrophotometer, respectively. Relative Vickers hardness was proceeded with similar specimens used in the F assay (4 periods). SEM/EDS was additionally performed. Statistical analyses were calculated in each parameter (p < 0.05). RESULT Hardness of several ILMs immediately increased after recharge. After 28d, Ketac Universal [a high-viscosity glass-ionomer cement (HVGIC)] showed the highest hardness similar to the resin composite control. Although 2 HVGICs (Zirconomer and Equia Forte Fil) ranked as first and second for F release/re-release, some HVGICs had inferior or comparable F capacity to RMGICs (Fuji VIII and Fuji II LC) and a resin-based (RB) ILM (Cention N). Cention N, Activa-Restorative (RB-ILM), and Zirconomer were the top-3 ranking for Ca release/re-release. Activa-Restorative showed the highest P release, whereas Cention N displayed the greatest recharge ability for P. CONCLUSIONS Zirconomer showed a versatile performance for ion-release/re-release, especially for F. Cention N had excellent capacity in relation to Ca release and recharge ability of Ca/P. CLINICAL SIGNIFICANCE With the F varnish recharge protocol, Zirconomer, Equia Forte, and Fuji VIII seems to have an ability to inhibit initial caries initiation. Cention N is a promising resin-based material that could be an alternative for high caries risk patients due to the high Ca release/recharge with acceptable F release.
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Affiliation(s)
- Chirayu Ruengrungsom
- Melbourne Dental School, The University of Melbourne, Melbourne, VIC, Australia.
| | - Michael F Burrow
- Faculty of Dentistry, Prince Philip Dental Hospital, University of Hong Kong, Hong Kong SAR, China.
| | - Peter Parashos
- Melbourne Dental School, The University of Melbourne, Melbourne, VIC, Australia.
| | - Joseph E A Palamara
- Melbourne Dental School, The University of Melbourne, Melbourne, VIC, Australia.
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Comba A, Scotti N, Maravić T, Mazzoni A, Carossa M, Breschi L, Cadenaro M. Vickers Hardness and Shrinkage Stress Evaluation of Low and High Viscosity Bulk-Fill Resin Composite. Polymers (Basel) 2020; 12:polym12071477. [PMID: 32630127 PMCID: PMC7407633 DOI: 10.3390/polym12071477] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/28/2020] [Accepted: 06/29/2020] [Indexed: 11/23/2022] Open
Abstract
The aim of this in vitro study was to evaluate the hardness and shrinkage stress (SS) of six bulk-fill resin composites. To evaluate microhardness (MH), ten 6 mm specimens were prepared using a metal mold for each selected bulk-fill resin composite and irradiated from the top side for 40 s using an LED light. After 24 h of storage, Vickers MH was evaluated on the upper, lower and lateral sides of the specimens. SS evaluation was then performed with a universal machine, which evaluated the contraction force generated by a bulk-fill composite specimen placed between two metal cylinders during and after light curing. The results were evaluated with a one-way ANOVA test with a post-hoc Bonferroni test and linear regression analysis (p < 0.05). All materials showed a significant MH decrease between the top and bottom surfaces. However, the bulk-fill materials tested performed differently when considering lateral depth progression. ANOVA tests for SS evaluation showed that both SDR and Venus Bulk Fill had significantly lower stress during irradiation than other tested materials. Further, MH decrease became significantly lower from the top surface at different depths in each tested group. Among the different resins, Venus Bulk Fill and SDR showed not only inferior hardness, but also a significant reduction in SS.
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Affiliation(s)
- Allegra Comba
- Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, Italy; (A.C.); (T.M.); (A.M.); (L.B.)
| | - Nicola Scotti
- Department of Surgical Science, CIR Dental School, University of Turin, Via Nizza 230, 10126 Turin, Italy;
- Correspondence: ; Tel.: +39-340-2861799
| | - Tatjana Maravić
- Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, Italy; (A.C.); (T.M.); (A.M.); (L.B.)
| | - Annalisa Mazzoni
- Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, Italy; (A.C.); (T.M.); (A.M.); (L.B.)
| | - Massimo Carossa
- Department of Surgical Science, CIR Dental School, University of Turin, Via Nizza 230, 10126 Turin, Italy;
| | - Lorenzo Breschi
- Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, Alma Mater Studiorum, Via San Vitale 59, 40125 Bologna, Italy; (A.C.); (T.M.); (A.M.); (L.B.)
| | - Milena Cadenaro
- Department of Medical Sciences, University of Trieste, Strada di Fiume 447, 34149 Trieste, Italy;
- Institute for Maternal and Child Health—IRCCS “Burlo Garofolo”, Via dell’Istria 65/1, 34137 Trieste, Italy
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12
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Limited reciprocity in curing efficiency of bulk-fill resin-composites. Dent Mater 2020; 36:997-1008. [PMID: 32499190 DOI: 10.1016/j.dental.2020.04.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/29/2020] [Accepted: 04/29/2020] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The aim of the study was to identify experimental limits of the general reciprocity hypothesis that the same photo-cure outcomes will result from applying essentially constant energy densities, despite reciprocal variations in the irradiance and irradiation time-period, for a representative set of bulk fill (BF) and non-BF resin composites. METHODS Six BF and two non-BF resin-composites were selected. The unset pastes were inserted into white acetal molds (5mm id) with (n=6) depths (1, 2, 3, 4, 5 and 6mm). Three light curing units (LCUs) of increasing radiant emittance capability: 1200, 2000 and 3200mW/cm2 were used. Composite specimen groups (n=3, per depth, per LCU) were irradiated on the upper surface only. For each specific composite, the irradiation times for each LCU were reduced reciprocally, as the LCU irradiance increased, to deliver a constant energy density (J/cm2) to that composite. However, the required energy density for a given composite differed in accordance with each composite manufacturer recommendations. After storing for 24h at 37°C, light transmission measurements were made through each specimen and re-expressed as Apparent Absorbance (A'). Vickers hardness (HV) measurements (n=10) were made on both top and bottom surfaces, for each specimen, and HVversus "depth" profile plots created. From the top-surface data, a Depth-of-Cure parameter could be derived. Data were statistically evaluated for differences between top and bottom HV values and for other predefined variables of interest. RESULTS Irradiation with the LCU of 1200mW/cm2 generally gave the highest HV/depth for most materials tested compared to the other curing lights with higher power output, regardless of top and bottom measurements (p<0.001). However, this difference was material-dependent. With one BF composite, 1200 and 2000mW/cm2 irradiance did not show a significant difference between top and bottom HV. Composites with higher translucency showed reduced differences in top/bottom HV than more opaque composites. SIGNIFICANCE Reciprocity was found to be limited with most materials examined, such that irradiance periods of 10s, gave generally better HV outcomes than by using LCUs of superior radiant emittance while reciprocally reducing irradiance time to maintain constant dose of energy density.
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Pieniak D, Walczak A, Walczak M, Przystupa K, Niewczas AM. Hardness and Wear Resistance of Dental Biomedical Nanomaterials in a Humid Environment with Non-Stationary Temperatures. MATERIALS 2020; 13:ma13051255. [PMID: 32164254 PMCID: PMC7085084 DOI: 10.3390/ma13051255] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/06/2020] [Accepted: 03/08/2020] [Indexed: 11/16/2022]
Abstract
This study discusses a quantitative fatigue evaluation of polymer-ceramic composites for dental restorations, i.e., commercial material (Filtek Z550) and experimental materials Ex-nano (G), Ex-flow (G). Their evaluation is based on the following descriptors: microhardness, scratch resistance, and sliding wear. In order to reflect factors of environmental degradation conditions, thermal fatigue was simulated with a special computer-controlled device performing algorithms of thermocycling. Specimens intended for the surface strength and wear tests underwent 104 hydrothermal fatigue cycles. Thermocycling was preceded by aging, which meant immersing the specimens in artificial saliva at 37 °C for 30 days. Microhardness tests were performed with the Vickers hardness test method. The scratch test was done with a Rockwell diamond cone indenter. Sliding ball-on-disc friction tests were performed against an alumina ball in the presence of artificial saliva. A direct positive correlation was found between thermocycling fatigue and microhardness. The dominant mechanism of the wear of the experimental composites after thermocycling is the removal of fragments of the materials in the form of flakes from the friction surface (spalling). Hydrothermal fatigue is synergistic with mechanical fatigue.
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Affiliation(s)
- Daniel Pieniak
- Department of Mechanics and Machine Building, University of Economics and Innovations in Lublin, Projektowa 4, 20-209 Lublin, Poland;
| | - Agata Walczak
- The Main School of Fire Service, Faculty of Safety Engineering and Civil Protection, Slowackiego 52/54, 01-629 Warsaw, Poland;
| | - Mariusz Walczak
- Department of Materials Engineering, Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618, Lublin, Poland;
| | - Krzysztof Przystupa
- Department of Automation, Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618, Lublin, Poland
- Correspondence:
| | - Agata M. Niewczas
- Department of Conservative Dentistry with Endodontics, Medical University of Lublin, Karmelicka 7, 20-080 Lublin, Poland;
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Lin CH, Lin YM, Lai YL, Lee SY. Mechanical properties, accuracy, and cytotoxicity of UV-polymerized 3D printing resins composed of Bis-EMA, UDMA, and TEGDMA. J Prosthet Dent 2019; 123:349-354. [PMID: 31202550 DOI: 10.1016/j.prosdent.2019.05.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 04/02/2019] [Accepted: 05/01/2019] [Indexed: 12/21/2022]
Abstract
STATEMENT OF PROBLEM Three-dimensional printing has the potential for clinical applications, and additive manufacturing materials for dental use merit further investigation. PURPOSE The purpose of this in vitro study was to evaluate the properties of materials formulated with ethoxylated bisphenol A-dimethacrylate (Bis-EMA), urethane dimethacrylate (UDMA), and triethylene glycol dimethacrylate (TEGDMA) as 3D printing resins for ultraviolet digital light processing (UV-DLP) 3D printers and to characterize the mechanical and biological properties and accuracy of the printed objects. MATERIAL AND METHODS Ten different light-polymerized resins were formulated using Bis-EMA, UDMA, and TEGDMA. Their viscosities were measured, and only 7 resins with viscosities lower than 1500 centipoise (cP) were selected for 3D printing and further material characterization. The light-polymerized resins were printed into representative shapes using a custom-made 3D printer equipped with a 405-nm UV-DLP projector as the light source. The printed specimens were subjected to biologic, mechanical, and accuracy tests, and the data were submitted to 1-way ANOVA and Tukey post hoc comparisons (α=.05). RESULTS Photopolymerizable resins made of Bis-EMA, UDMA, and TEGDMA were successfully formulated for 3D printing to fabricate objects of various shapes and sizes. TEGDMA served as the diluent to reduce the viscosity and increase the degree of conversion, while UDMA and Bis-EMA provided strength as demonstrated by the mechanical testing. All the printed objects passed cytotoxicity testing. The flexural strengths of the printed specimens ranged between 60 MPa and 90 MPa; flexural modulus ranged between 1.7 GPa and 2.1 GPa; and surface hardness ranged between 14.5 HV and 24.6 HV. These represent similar mechanical properties to those of currently used clinical resin materials. In the accuracy test, the resin mixture composed of 80% Bis-EMA, 10% UDMA, and 10% TEGDMA had the highest accuracy, with a 0.051-mm deviation from the original design. CONCLUSIONS Bis-EMA, UDMA, and TEGDMA are good candidates for the formulation of 3D printing resins for dental use. The printed objects demonstrated favorable biological and mechanical properties. Further, the accuracy of the printed specimens showed potential for clinical application.
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Affiliation(s)
- Chih-Hsin Lin
- Postdoctoral Researcher, Department of Dentistry, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Yuan-Min Lin
- Associate Professor, Department of Dentistry, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Yu-Lin Lai
- Chairperson, Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China
| | - Shyh-Yuan Lee
- Professor, Department of Dentistry, National Yang-Ming University, Taipei, Taiwan; Attending Doctor, Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China; Researcher, Department of Dentistry, Taipei City Hospital, Taipei, Taiwan, Republic of China.
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Al-Zain AO, Eckert GJ, Platt JA. The Influence of Distance on Radiant Exposure and Degree of Conversion Using Different Light-Emitting-Diode Curing Units. Oper Dent 2019; 44:E133-E144. [DOI: 10.2341/18-004-l] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Objectives:
To investigate the influence of curing distance on the degree of conversion (DC) of a resin-based composite (RBC) when similar radiant exposure was achieved using six different light-curing units (LCUs) and to explore the correlation among irradiance, radiant exposure, and DC.
Methods and Materials:
A managing accurate resin curing-resin calibrator system was used to collect irradiance data for both top and bottom specimen surfaces with a curing distance of 2 mm and 8 mm while targeting a consistent top surface radiant exposure. Square nanohybrid-dual-photoinitiator RBC specimens (5 × 5 × 2 mm) were cured at each distance (n=6/LCU/distance). Irradiance and DC (micro-Raman spectroscopy) were determined for the top and bottom surfaces. The effect of distance and LCU on irradiance, radiant exposure, and DC as well as their linear associations were analyzed using analysis of variance and Pearson correlation coefficients, respectively (α=0.05).
Results:
While maintaining a similar radiant exposure, each LCU exhibited distinctive patterns in decreased irradiance and increased curing time. No significant differences in DC values (63.21%-70.28%) were observed between the 2- and 8-mm distances, except for a multiple-emission peak LCU. Significant differences in DC were detected among the LCUs. As expected, irradiance and radiant exposure were significantly lower on the bottom surfaces. However, a strong correlation between irradiance and radiant exposure did not necessarily result in a strong correlation with DC.
Conclusions:
The RBC exhibited DC values >63% when the top surface radiant exposure was maintained, although the same values were not reached for all lights. A moderate-strong correlation existed among irradiance, radiant exposure, and DC.
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Affiliation(s)
- AO Al-Zain
- Afnan O Al-Zain, BDS, MSD, PhD, King Abdulaziz University, Faculty of Dentistry, Restorative Dentistry Department, Jeddah, Saudi Arabia
| | - GJ Eckert
- George J Eckert, MS, Indiana University School of Medicine, Division of Biostatistics, Indianapolis, IN, USA
| | - JA Platt
- Jeffrey A Platt, DDS, MS, Indiana University, Department of Biomedical and Applied Sciences, Indianapolis, IN, USA
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Hassan MA, Zinelis S, Hersberger-Zurfluh M, Eliades T. Creep, Hardness, and Elastic Modulus of Lingual Fixed Retainers Adhesives. MATERIALS 2019; 12:ma12040646. [PMID: 30795503 PMCID: PMC6416616 DOI: 10.3390/ma12040646] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/04/2019] [Accepted: 02/19/2019] [Indexed: 11/16/2022]
Abstract
The aims of this study were twofold: a) to characterize a wide array of time-independent and -dependent properties and b) to find possible correlations among the properties tested. Seven commercially available orthodontic adhesives were included in this study and ten cylindrical specimens were prepared from each material. Five specimens from each material were used for the characterization of Martens Hardness (HM), indentation modulus (EIT), and elastic index (ηIT), and the remaining five for the determination of indentation creep (CIT). Al the aforementioned properties were identified by employing an Instrumented Indentations Testing (IIT) device with a Vickers indenter. The results of HM, EIT, ηIT, and CIT were statistically analyzed by one way ANOVA and Tukey post hoc test, while the possible correlations among the aforementioned properties were determined by Spearman correlation test. Statistical significant differences were identified for all properties among the materials tested. Spearman correlation reveals that HM has a positive correlation with EIT. Both properties demonstrated a negative correlation with ηIT and CIT, while no correlation was identified between ηIT and CIT. Significant differences in the mechanical properties tested may also imply differences in their clinical behavior and efficacy.
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Affiliation(s)
- Manar A Hassan
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
| | - Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
| | - Monika Hersberger-Zurfluh
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
| | - Theodore Eliades
- Clinic of Orthodontics and Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
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Najafi H, Akbari B, Najafi F, Shahabi S, Abrishamkar A, Moztarzadeh F, Yazdanpanah A. Characterization of the physical–mechanical properties of dental resin composites reinforced with novel micro-nano hybrid silica particles: An optimization study. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2019. [DOI: 10.1080/10601325.2018.1526040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Hamed Najafi
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Babak Akbari
- Division of Biomedical Engineering, Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran
| | - Farhood Najafi
- Department of Resin and Additives, Institute for Color Science and Technology, Tehran, Iran
| | - Sima Shahabi
- Laser Research Center of Dentistry, Tehran University of Medical Science, Tehran, Iran
| | | | - Fathollah Moztarzadeh
- Biomaterials Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran, Iran
| | - Abolfazl Yazdanpanah
- Biomaterials Group, Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran, Iran
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18
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Al-Zain AO, Eckert GJ, Lukic H, Megremis S, Platt JA. Polymerization pattern characterization within a resin-based composite cured using different curing units at two distances. Clin Oral Investig 2019; 23:3995-4010. [PMID: 30737620 DOI: 10.1007/s00784-019-02831-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 01/25/2019] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To investigate the relationship of the irradiance-beam-profile areas from six different light-curing units (LCUs) with the degree of conversion (DC), microhardness (KH), and cross-link density (CLD) throughout a resin-based composite (RBC) cured at two clinically relevant distances, and to explore the correlations among them. MATERIALS AND METHODS A mapping approach was used to measure DC using micro-Raman spectroscopy, KH using a Knoop indentor on a hardness tester, and %KH reduction after ethanol exposure, as an indicator for CLD within a nano-hybrid RBC increment (n = 3) at various depths. These sample composites were cured from two distances while maintaining the radiant exposure, using six different light-curing units: one quartz-tungsten-halogen; two single and three multiple-emission-peak light-emitting-diode units. Irradiance beam profiles were generated for each LCU at both distances, and localized irradiance values were calculated. Points across each depth were analyzed using repeated measures ANOVA. Correlations across multiple specimen locations and associations between beam uniformity corresponding with polymerization measurements were calculated using linear mixed models and Pearson correlation coefficients. RESULTS Significant non-uniform polymerization patterns occurred within the specimens at various locations and depths. At 2-mm curing distance, the localized DC = 52.7-76.8%, KH = 39.0-66.7 kg/mm2, and %KH reduction = 26.7-57.9%. At 8-mm curing distance, the localized DC = 50.4-78.6%, KH = 40.3-73.7 kg/mm2, and %KH reduction = 28.2-56.8%. The localized irradiance values were weakly correlated with the corresponding DC, KH, and %KH reduction, with only a few significant correlations (p < 0.05). CONCLUSIONS Although significant differences were observed at each depth within the specimens, the localized irradiance values for all LCUs did not reflect the polymerization pattern and did not seem to have a major influence on polymerization patterns within the RBC, regardless of the curing distance. CLINICAL RELEVANCE Commonly used LCUs do not produce uniform polymerization regardless of the curing distance, which may contribute to the risk of RBC fracture.
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Affiliation(s)
- Afnan O Al-Zain
- Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, P.O. Box: 80209, Jeddah, 21589, Saudi Arabia.
| | - George J Eckert
- Department of Biostatistics, Indiana University School of Medicine, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
| | - Henry Lukic
- Research and Standards, American Dental Association Science Institute, Chicago, IL, USA
| | - Spiro Megremis
- Research and Standards, American Dental Association Science Institute, Chicago, IL, USA
| | - Jeffrey A Platt
- Department of Biomedical and Applied Sciences, Indiana University School of Dentistry, Indiana University Purdue University Indianapolis, Indianapolis, IN, USA
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19
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Photo-calorimetry method optimization for the study of light-initiated radical polymerization of dental resins. POLYMER 2018. [DOI: 10.1016/j.polymer.2017.12.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Garoushi S, Vallittu PK, Lassila L. Characterization of fluoride releasing restorative dental materials. Dent Mater J 2017; 37:293-300. [PMID: 29279547 DOI: 10.4012/dmj.2017-161] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study aimed to evaluate and compare certain mechanical properties, Vickers-hardness, water sorption, fluoride-release, shrinkage-stress and wear of five commercial fluoride-releasing restorative materials (Dyract, CompGlass, BEAUTIFIL II, ACTIVA-Restorative, and GC Fuji II LC), in relation to their microstructural characteristics. Mechanical properties were determined for each material following ISO standards. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Daily fluoride-release was measured during the first 10 days by using a fluoride ion selective electrode. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Results were statistically analysed using ANOVA followed by post hoc Tukey's test. ACTIVA-Restorative exhibited the highest fracture toughness (1.1 MPa m1/2) among the materials tested. BEAUTIFIL II presented the highest flexural strength (145 MPa) which was not significantly different (p>0.05) from CompGlass and Dyract. Highest fluoride-release measurement was located for GC Fuji II LC among other tested materials.
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Affiliation(s)
- Sufyan Garoushi
- Department of Biomaterials Science and Turku Clinical Biomaterials Center -TCBC Institute of Dentistry, University of Turku
| | - Pekka K Vallittu
- Department of Biomaterials Science and Turku Clinical Biomaterials Center -TCBC Institute of Dentistry, University of Turku.,City of Turku Welfare Division, Oral Health Care
| | - Lippo Lassila
- Department of Biomaterials Science and Turku Clinical Biomaterials Center -TCBC Institute of Dentistry, University of Turku
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21
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Ferracane J, Hilton T, Stansbury J, Watts D, Silikas N, Ilie N, Heintze S, Cadenaro M, Hickel R. Academy of Dental Materials guidance—Resin composites: Part II—Technique sensitivity (handling, polymerization, dimensional changes). Dent Mater 2017; 33:1171-1191. [DOI: 10.1016/j.dental.2017.08.188] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 08/29/2017] [Indexed: 11/30/2022]
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Al-Zain AO, Eckert GJ, Lukic H, Megremis SJ, Platt JA. Degree of conversion and cross-link density within a resin-matrix composite. J Biomed Mater Res B Appl Biomater 2017; 106:1496-1504. [DOI: 10.1002/jbm.b.33960] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 06/22/2017] [Accepted: 07/04/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Afnan O. Al-Zain
- Department of Operative Dentistry; Faculty of Dentistry, King Abdulaziz University; Jeddah Kingdom of Saudi Arabia
- Department of Biomedical and Applied Sciences; Indiana University School of Dentistry, Indiana University Purdue University Indianapolis; Indianapolis IN
| | - George J. Eckert
- Biostatistician Supervisor; Department of Biostatistics, Indiana University School of Medicine, Indiana University Purdue University Indianapolis; Indianapolis IN
| | - Henry Lukic
- Research and Laboratories, American Dental Association Division of Science; Chicago IL
| | - Spiro J. Megremis
- Research and Laboratories, American Dental Association Division of Science; Chicago IL
| | - Jeffrey A. Platt
- Department of Biomedical and Applied Sciences; Indiana University School of Dentistry, Indiana University Purdue University Indianapolis; Indianapolis IN
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Van Ende A, Lise DP, De Munck J, Vanhulst J, Wevers M, Van Meerbeek B. Strain development in bulk-filled cavities of different depths characterized using a non-destructive acoustic emission approach. Dent Mater 2017; 33:e165-e177. [DOI: 10.1016/j.dental.2016.12.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 12/21/2016] [Accepted: 12/22/2016] [Indexed: 11/15/2022]
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Sifakakis I, Zinelis S, Patcas R, Eliades T. Mechanical properties of contemporary orthodontic adhesives used for lingual fixed retention. ACTA ACUST UNITED AC 2017; 62:289-294. [DOI: 10.1515/bmt-2015-0165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 05/11/2016] [Indexed: 11/15/2022]
Abstract
AbstractObjective:The aim of the present study was to test the mechanical properties of different adhesives used in orthodontics for fixed retainers and to investigate their possible interrelations.Materials and methods:Specimens of six different adhesive resins were prepared: Transbond XT, Transbond LR and an experimental BPA-free orthodontic adhesive, as well as IPS Empress Direct (IPS-ED), ZNano and Accolade. The mechanical properties tested were Martens hardness (HM), indentation modulus (EResults:Significant differences were identified among all the materials tested for HM, with Transbond LR presenting the highest value. This resin presented the highest EConclusions:The materials tested demonstrated significant differences in their mechanical properties, and thus differences in their clinical performance are anticipated.
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Shrinkage behaviors of dental composite restorations—The experimental–numerical hybrid analysis. Dent Mater 2016; 32:e362-e373. [DOI: 10.1016/j.dental.2016.09.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 02/15/2016] [Accepted: 09/03/2016] [Indexed: 11/20/2022]
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Price RBT, Labrie D, Rueggeberg FA, Sullivan B, Kostylev I, Fahey J. Correlation between the beam profile from a curing light and the microhardness of four resins. Dent Mater 2016; 30:1345-57. [PMID: 25460008 DOI: 10.1016/j.dental.2014.10.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 07/29/2014] [Accepted: 10/07/2014] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To demonstrate the effect of localized irradiance and spectral distribution inhomogeneities of one LED-based dental light-curing unit (LCU) on the corresponding microhardness values at the top, and bottom surfaces of four dental resin-based composites (RBCs), which contained either camphorquinone (CQ) alone or a combination of CQ and monoacylphosphine oxide (TPO) as photoinitiators. METHODS Localized irradiance beam profiles from a polywave LED-based LCU were recorded five times using a laser beam analyzer, without and with either a 400 nm or 460 nm narrow bandpass filter placed in front of the camera lens. Five specimens of each of the four RBCs (two containing CQ/TPO and two containing CQ-only) were exposed for 5-, 10-, or 30-s with the light guide directly on the top surface of the RBC. After 24 h, Knoop microhardness values were measured at 45 locations across the top and bottom surfaces of each specimen. Microhardness readings for each RBC surface and exposure time were correlated with localized patterns of the LCU beam profile, measured using the 400 nm and 460 nm bandpass filters. Spearman rank correlation was used to avoid relying on an assumption of a bivariate normal distribution for the KHN and irradiance. RESULTS The local irradiance and spectral emission values were not uniformly distributed across the light tip. There was a strong significant positive correlation with the irradiance beam profile values from the LCU taken through bandpass filters and the microhardness maps of the RBC surfaces exposed for 5 and 10 s. The strength of this correlation decreased with increasing exposure time for the RBCs containing CQ only, and increased for the RBCs containing both CQ and TPO. CONCLUSIONS Localized beam and spectral distributions across the tip end of the light guide strongly correlated with corresponding areas of microhardness in both the top and bottom surfaces among four RBCs with different photoinitiator contents. Significance: A light-curing unit with a highly inhomogeneous light output can adversely affect localized microhardness of resin-based composites and this may be a contributing factor for premature failure of a restoration.
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Affiliation(s)
- Richard B T Price
- Dental Clinical Sciences, Dalhousie University, Halifax, NS, Canada.
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Roedel L, Bednarzig V, Belli R, Petschelt A, Lohbauer U, Zorzin J. Self-adhesive resin cements: pH-neutralization, hydrophilicity, and hygroscopic expansion stress. Clin Oral Investig 2016; 21:1735-1741. [PMID: 27664153 DOI: 10.1007/s00784-016-1947-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 08/23/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVES The objective of the study was to investigate the relationship between pH-neutralization, hydrophilicity, and free hygroscopic expansion stress of self-adhesive resin cements (SARCs) after storage in artificial saliva. MATERIALS AND METHODS The SARCs RelyX Unicem Automix 2 (RX2, 3 M ESPE), iCEM (iCEM, Heraeus) and Maxcem Elite (MCE, Kerr) were under investigation in this study. Cylinders (height × diameter, 6 × 4mm) were prepared from each material and stored in artificial saliva (7d at 37 °C). Cylinder height was measured at baseline and after 7 days. After storage, the compression modulus was measured to calculate the free hygroscopic expansion stress. For pH-neutralization and hydrophilicity assessment, disks (height × diameter, 1 × 1.5 mm) were prepared, covered with electrolyte, and monitored over 24 h at 37 °C. Hydrophilicity was assessed using the static sessile drop technique at baseline and at different time intervals up to 24 h. Data were analyzed using one-way ANOVA and post hoc Student-Newman-Keuls test (S-N-K, α = 0.05). RESULTS After 24 h, RX2 (pH24h 4.68) had a significantly higher (p < 0.05) pH-value than MCE (pH24h 4.2) and iCEM (pH24h 3.23). iCEM showed the significantly highest hydrophilicity (p < 0.05) after 24 h (θ24h 85.02°), while MCE resulted lower (θ24h 113.01°) in comparison with RX2 (θ24h 108.11°). The resulting hygroscopic expansion stress of iCEM (29.15 MPa) was significantly higher (p < 0.05) compared to RX2 (14.5 MPa) and MCE (21.02 MPa). CONCLUSIONS The material with lowest pH-neutralization capacity displayed higher hydrophilicity after 24 h and higher hygroscopic expansion stress after 7 days compared to those with high pH-neutralization. CLINICAL SIGNIFICANCE Remnant hydrophilicity due to low pH-neutralization of SARCs could lead to cement interface stress build-up and long-term failure of silicate ceramic restorations.
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Affiliation(s)
- Lena Roedel
- Dental Clinic 1-Operative Dentistry and Periodontology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Glückstr. 11, 91054, Erlangen, Germany
| | - Vera Bednarzig
- Dental Clinic 1-Operative Dentistry and Periodontology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Glückstr. 11, 91054, Erlangen, Germany
| | - Renan Belli
- Dental Clinic 1-Operative Dentistry and Periodontology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Glückstr. 11, 91054, Erlangen, Germany
| | - Anselm Petschelt
- Dental Clinic 1-Operative Dentistry and Periodontology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Glückstr. 11, 91054, Erlangen, Germany
| | - Ulrich Lohbauer
- Dental Clinic 1-Operative Dentistry and Periodontology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Glückstr. 11, 91054, Erlangen, Germany
| | - José Zorzin
- Dental Clinic 1-Operative Dentistry and Periodontology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Glückstr. 11, 91054, Erlangen, Germany.
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Effect of curing light emission spectrum on the nanohardness and elastic modulus of two bulk-fill resin composites. Dent Mater 2016; 32:535-50. [DOI: 10.1016/j.dental.2015.12.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 12/21/2015] [Accepted: 12/21/2015] [Indexed: 02/01/2023]
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Zhang L, Weir MD, Chow LC, Antonucci JM, Chen J, Xu HHK. Novel rechargeable calcium phosphate dental nanocomposite. Dent Mater 2015; 32:285-93. [PMID: 26743970 DOI: 10.1016/j.dental.2015.11.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 05/07/2015] [Accepted: 11/30/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVES Calcium phosphate (CaP) composites with Ca and P ion release can remineralize tooth lesions and inhibit caries. But the ion release lasts only a few months. The objectives of this study were to develop rechargeable CaP dental composite for the first time, and investigate the Ca and P recharge and re-release of composites with nanoparticles of amorphous calcium phosphate (NACP) to achieve long-term inhibition of caries. METHODS Three NACP nanocomposites were fabricated with resin matrix of: (1) bisphenol A glycidyl dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) at 1:1 mass ratio (referred to as BT group); (2) pyromellitic glycerol dimethacrylate (PMGDM) and ethoxylated bisphenol A dimethacrylate (EBPADMA) at 1:1 ratio (PE group); (3) BisGMA, TEGDMA, and Bis[2-(methacryloyloxy)ethyl] phosphate (BisMEP) at 2:1:1 ratio (BTM group). Each resin was filled with 20% NACP and 50% glass particles, and the composite was photo-cured. Specimens were tested for flexural strength and elastic modulus, Ca and P ion release, and Ca and P ion recharge and re-release. RESULTS NACP nanocomposites had strengths 3-fold of, and elastic moduli similar to, commercial resin-modified glass ionomer controls. CaP ion recharge capability was the greatest for PE group, followed by BTM group, with BT group being the lowest (p<0.05). For each recharge cycle, CaP re-release reached similarly high levels, showing that CaP re-release did not decrease with more recharge cycles. After six recharge/re-release cycles, NACP nanocomposites without further recharge had continuous CaP ion release for 42 d. SIGNIFICANCE Novel rechargeable CaP composites achieved long-term and sustained Ca and P ion release. Rechargeable NACP nanocomposite is promising for caries-inhibiting restorations, and the Ca and P ion recharge and re-release method has wide applicability to dental composites, adhesives, cements and sealants to achieve long-term caries-inhibition.
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Affiliation(s)
- Ling Zhang
- State Key laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an 710032, China; Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA
| | - Michael D Weir
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA
| | - Laurence C Chow
- Dr Anthony Volpe Research Center, American Dental Association Foundation (ADAF), National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Joseph M Antonucci
- Biomaterials Group, Biosystems & Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Jihua Chen
- State Key laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an 710032, China
| | - Hockin H K Xu
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA; Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Mechanical Engineering, University of Maryland, Baltimore County, MD 21250, USA.
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Effect of mold type, diameter, and uncured composite removal method on depth of cure. Clin Oral Investig 2015; 20:1699-707. [PMID: 26631060 DOI: 10.1007/s00784-015-1672-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 11/18/2015] [Indexed: 01/09/2023]
Abstract
OBJECTIVE This study compared the effects of mold material and diameter on the thickness of cured composite remnants and depth of cure (DOC) of resin-based composites (RBC). MATERIAL AND METHODS One Polywave® curing light was used to photo-cure two shades of the same "bulk-fill" RBC in 4, 6, or 10-mm internal diameter metal or white Delrin® molds. For 60 specimens, the uncured RBC was manually scraped away as described in the ISO 4049 depth of cure test. The remaining 60 specimens were immersed in tetrahydrofuran for 48 hours in the dark. Maximum lengths of remaining hard RBC and their DOC values were compared using analysis of variance (ANOVA) and Tukey-Kramer post hoc multiple comparison tests (α = 0.05). RESULTS Specimen thickness and DOC were always greater using the white Delrin® molds compared to metal molds (p < 0.001). Increase in mold diameter significantly increased specimen thickness and DOC when made in the metal molds and in the 6-mm diameter Delrin® molds (p < 0.01). Increasing the diameter of the Delrin® molds to 10-mm did not increase specimen thickness or DOC. Sectioning and staining of specimens revealed an internal, peripheral transition zone of porous RBC in the solvent-dissolved specimens only. CONCLUSION Mold material and internal diameter significantly influenced cured composite remnant thickness as well as depth of cure. The existence of an outer region of RBC that is hard, yet susceptible to solvent dissolution, requires further investigation. CLINICAL RELEVANCE The depth of cure results obtained from a 4-mm diameter metal mold may not represent the true potential for evaluating composite depth of cure. A universally acceptable mold material and diameter size need to be established if this type of testing is to be useful for evaluating the relative performance of a given type of LCU and RBC.
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ALShaafi MM, Haenel T, Sullivan B, Labrie D, Alqahtani MQ, Price RB. Effect of a broad-spectrum LED curing light on the Knoop microhardness of four posterior resin based composites at 2, 4 and 6-mm depths. J Dent 2015; 45:14-8. [PMID: 26593741 DOI: 10.1016/j.jdent.2015.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE To measure the Knoop microhardness at the bottom of four posterior resin-based composites (RBCs): Tetric EvoCeram Bulk Fill (Ivoclar Vivadent), SureFil SDR flow (DENTSPLY), SonicFill (Kerr), and x-tra fil (Voco). METHODS The RBCs were expressed into metal rings that were 2, 4, or 6-mm thick with a 4-mm internal diameter at 30°C. The uncured specimens were covered by a Mylar strip and a Bluephase 20i (Ivoclar Vivadent) polywave(®) LED light-curing unit was used in high power setting for 20s. The specimens were then removed and placed immediately on a Knoop microhardness-testing device and the microhardness was measured at 9 points across top and bottom surfaces of each specimen. Five specimens were made for each condition. RESULTS As expected, for each RBC there was no significant difference in the microhardness values at the top of the 2, 4 and 6-mm thick specimens. SureFil SDR Flow was the softest resin, but was the only resin that had no significant difference between the KHN values at the bottom of the 2 and 4-mm (Mixed Model ANOVA p<0.05). Although the KHN of SureFil SDR Flow was only marginally significantly different between the 2 and 6-mm thickness, the bottom at 6-mm was only 59% of the hardness measured at the top. CLINICAL SIGNIFICANCE This study highlights that clinicians need to consider how the depth of cure was evaluated when determining the depth of cure. SureFil SDR Flow was the softest material and, in accordance with manufacturer's instructions, this RBC should be overlaid with a conventional resin.
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Affiliation(s)
- Maan M ALShaafi
- King Saud University, Restorative Dental Sciences, P.O. Box 60169, Riyadh 11545, Saudi Arabia
| | - Thomas Haenel
- Dental Clinical Sciences, Dalhousie University, P.O. Box 15000, Halifax, NS B3H4R2, Canada; University of Bonn-Rhein-Sieg, Applied Sciences, Department of Natural Sciences, von-Liebig-Strasse 20, 53359 Rhinebach, Germany; Tomas Bata University in Zlín, Faculty of Technology, náměstí T. G. Masaryka 275, 76272 Zlín, Czech Republic
| | - Braden Sullivan
- Dental Clinical Sciences, Dalhousie University, P.O. Box 15000, Halifax, NS B3H4R2, Canada
| | - Daniel Labrie
- Department of Physics and Atmospheric Science, Dalhousie University, P.O. BOX 15000, Halifax, NS B3H 4R2, Canada
| | - Mohammed Q Alqahtani
- King Saud University, Restorative Dental Sciences, P.O. Box 60169, Riyadh 11545, Saudi Arabia
| | - Richard B Price
- Dental Clinical Sciences, Dalhousie University, P.O. Box 15000, Halifax, NS B3H4R2, Canada.
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AlQahtani MQ, Michaud PL, Sullivan B, Labrie D, AlShaafi MM, Price RB. Effect of High Irradiance on Depth of Cure of a Conventional and a Bulk Fill Resin-based Composite. Oper Dent 2015; 40:662-72. [PMID: 26237638 DOI: 10.2341/14-244-l] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES This study evaluated the effect of using three commercial light curing units (LCUs) delivering a range of irradiance values, but delivering similar radiant exposures on the depth of cure of two different resin-based composites (RBCs). METHODS A conventional hybrid RBC (Z100 shade A2, 3M ESPE) or a bulk fill RBC (Tetric EvoCeram Bulk Fill shade IVA, Ivoclar Vivadent) was packed into a 10-mm deep semicircular metal mold with a 2-mm internal radius. The RBC was exposed to light from a plasma-arc-curing (PAC) light (Sapphire Plus, DenMat) for five seconds, a quartz-tungsten-halogen (QTH) light (Optilux 501, Kerr) for 40 seconds, or a light-emitting-diode (LED) light (S10, 3M ESPE) for 20 seconds and 40 seconds (control). The Knoop microhardness was then measured as soon as possible at the top surface and at three points every 0.5 mm down from the surface. For each RBC, a repeated measures analysis of variance (ANOVA) model was used to predict the Knoop hardness in a manner analogous to a standard regression model. This predicted value was used to determine at what depth the RBC reached 80% of the mean hardness achieved at the top surface with any light. RESULTS The PAC light delivered an irradiance and radiant exposure of 7328 mW/cm(2) and 36.6 J/cm(2), respectively, to the RBCs; the QTH light delivered 936 mW/cm(2) and 37.4 J/cm(2) and in 20 seconds the LED light delivered 1825 mW/cm(2) and 36.5 J/cm(2). In 40 seconds, the control LED light delivered a radiant exposure of 73.0 J/cm(2). For Z100, using 80% of the maximum hardness at the top surface as the criteria for adequate curing, all light exposure conditions achieved the 2.0-mm depth of cure claimed by the manufacturer. The LED light used for 40 seconds achieved the greatest depth of cure (5.0 mm), and the PAC light used for five seconds, the least (2.5 mm). Tetric EvoCeram Bulk Fill achieved a 3.5-mm depth of cure when the broad-spectrum QTH light was used for 40 seconds delivering 37.4 J/cm(2). It required a 40-second exposure time with the narrow-spectrum LED, delivering approximately 73 J/cm(2) to reach a depth of cure of 4 mm. CONCLUSIONS When delivering a similar radiant exposure of 37 J/cm(2), the QTH (40 seconds) and LED (20 seconds) units achieved a greater depth of cure than the PAC (five seconds) light. For both resins, the greatest depth of cure was achieved when the LED light was used for 40 seconds delivering 73 J/cm(2) (p<0.05).
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Zorzin J, Maier E, Harre S, Fey T, Belli R, Lohbauer U, Petschelt A, Taschner M. Bulk-fill resin composites: Polymerization properties and extended light curing. Dent Mater 2015; 31:293-301. [DOI: 10.1016/j.dental.2014.12.010] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 11/07/2014] [Accepted: 12/16/2014] [Indexed: 12/15/2022]
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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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Wang Z, Landis FA, Giuseppetti AAM, Lin-Gibson S, Chiang MYM. Simultaneous measurement of polymerization stress and curing kinetics for photo-polymerized composites with high filler contents. Dent Mater 2014; 30:1316-24. [PMID: 25443160 PMCID: PMC4573543 DOI: 10.1016/j.dental.2014.09.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/29/2014] [Accepted: 09/23/2014] [Indexed: 11/19/2022]
Abstract
OBJECTIVES Photopolymerized composites are used in a broad range of applications with their performance largely directed by reaction kinetics and contraction accompanying polymerization. The present study was to demonstrate an instrument capable of simultaneously collecting multiple kinetics parameters for a wide range of photopolymerizable systems: degree of conversion (DC), reaction exotherm, and polymerization stress (PS). METHODS Our system consisted of a cantilever beam-based instrument (tensometer) that has been optimized to capture a large range of stress generated by lightly-filled to highly-filled composites. The sample configuration allows the tensometer to be coupled to a fast near infrared (NIR) spectrometer collecting spectra in transmission mode. RESULTS Using our instrument design, simultaneous measurements of PS and DC are performed, for the first time, on a commercial composite with ≈80% (by mass) silica particle fillers. The in situ NIR spectrometer collects more than 10 spectra per second, allowing for thorough characterization of reaction kinetics. With increased instrument sensitivity coupled with the ability to collect real time reaction kinetics information, we show that the external constraint imposed by the cantilever beam during polymerization could affect the rate of cure and final degree of polymerization. SIGNIFICANCE The present simultaneous measurement technique is expected to provide new insights into kinetics and property relationships for photopolymerized composites with high filler content such as dental restorative composites.
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Affiliation(s)
- Zhengzhi Wang
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
| | - Forrest A Landis
- Department of Chemistry, Penn State University - York Campus, York, PA 17403, United States
| | - Anthony A M Giuseppetti
- American Dental Association Foundation, Dr. Anthony Volpe Research Center, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
| | - Sheng Lin-Gibson
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States
| | - Martin Y M Chiang
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, United States.
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Oguz Ahmet S, Mutluay MM, Seyfioglu Polat Z, Seseogullari Dirihan R, Bek B, Tezvergil-Mutluay A. Addition of benzalkonium chloride to self-adhesive resin-cements: some clinically relevant properties. Acta Odontol Scand 2014; 72:831-8. [PMID: 24823935 DOI: 10.3109/00016357.2014.913307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The clinical survival rates of the adhesive restorations are limited due to the deterioration of resin-dentin bonds over time, partly due to the endogenous enzymatic activity of dentin. Recently, benzalkonium chloride (BAC) has been shown to effectively inhibit endogenous protease activity of dentin. This study evaluated the effect of different concentrations of benzalkonium chloride (BAC) on the degree of conversion (DC), vickers hardness (VH), setting time (ST) and biaxial flexural strength (FS) of two self-adhesive resin luting cements (RC). METHODS Two RC SpeedCEM (Ivoclar-Vivadent) and BisCem (Bisco) were modified by addition of 0.1, 0.5, 1, 1.5, 2 wt% BAC. The luting cements without the addition of BAC served as control. The DC (FT-IR/ATR from the bottom of the resin disc), vickers hardness (from top and bottom of the light-cured specimen), setting time (ISO 4049) and biaxial flexural strength (0.6 × 6 mm discs) of the specimens were tested. Data were analyzed using ANOVA and Tukeys HSD. RESULTS DC results were in the range of 70-80%, with some significant changes in BisCem (p < 0.05). VH values of both materials increased significantly compared to control, with no significant change as the BAC percentage increases. BAC addition influenced the ST differently for both materials. For BisCem, a gradual decrease (p < 0.05) was observed whereas, for SpeedCEM, a gradual increase was observed until 1% BAC (p < 0.05). For FS values, a gradual decrease was observed for both materials with increased amounts of BAC (p < 0.05), compared to the control group. CONCLUSIONS BAC addition of up to 1% seems to be acceptable considering the properties tested. Clinical significance. Incorporation of benzalkonium chloride to self-adhesive resin luting cements during the mixing procedure does not significantly affect the degree of conversion or flexural strength of the luting agent and may be a good option to improve the durability of adhesive interface.
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Affiliation(s)
- Serra Oguz Ahmet
- Medipol University, Faculty of Dentistry, Department of Prosthodontics , Turkey
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Fok ASL. Shrinkage stress development in dental composites--an analytical treatment. Dent Mater 2013; 29:1108-15. [PMID: 24029101 DOI: 10.1016/j.dental.2013.08.198] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 07/23/2013] [Accepted: 08/06/2013] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The aim of this paper is to develop a comprehensive mathematical model for shrinkage stress development in dental composites that can account for the combined effect of material properties, specimen geometry and external constraints. METHODS A viscoelastic model that includes the composite's elastic, creep and shrinkage strains, and their interaction with the sample's dimensions and the external constraint is developed. The model contains two dimensionless parameters. The first one represents the compliance of the external constraint relative to that of the composite sample, and the second controls the rate of shrinkage stress decay through creep. The resulting differential equation is solved for two special cases: zero compliance and zero creep. Predictions for shrinkage stress measurements are then made using the analytical solutions for instruments with different compliances, samples with different thicknesses and composites with different filler fractions. RESULTS The model correctly predicts how shrinkage stress increases with time, its dependence on the interaction between the entire system's compliance and the material properties, and the effect of the filler fraction on its maximum value. Comparisons with reported shrinkage stress measurements have provided very good agreement between theory and experiments. SIGNIFICANCE The results provided by the model can help to resolve most, if not all, of the seemingly conflicting experimental observations reported in the literature. They can also provide some useful guidelines for optimizing the mechanical performance of dental composite restorations. The compliance ratio, a new parameter derived from the model, represents a fuller description of the constraints of the system.
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Affiliation(s)
- Alex S L Fok
- Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, United States.
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Martinsen M, El-Hajjar RF, Berzins DW. 3D full field strain analysis of polymerization shrinkage in a dental composite. Dent Mater 2013; 29:e161-7. [PMID: 23735752 DOI: 10.1016/j.dental.2013.04.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 10/15/2012] [Accepted: 04/25/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Michael Martinsen
- Department of Civil Engineering & Mechanics, University of Wisconsin-Milwaukee, WI 53211, USA
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Thomaidis S, Kakaboura A, Mueller WD, Zinelis S. Mechanical properties of contemporary composite resins and their interrelations. Dent Mater 2013; 29:e132-41. [DOI: 10.1016/j.dental.2013.04.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/31/2013] [Accepted: 04/25/2013] [Indexed: 10/26/2022]
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Wang R, Lu C, Arola D, Zhang D. Plastic Damage Induced Fracture Behaviors of Dental Ceramic Layer Structures Subjected to Monotonic Load. J Prosthodont 2013; 22:456-64. [DOI: 10.1111/jopr.12035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2012] [Indexed: 11/28/2022] Open
Affiliation(s)
- Raorao Wang
- The Tenth People's Hospital of Tongji University; Shanghai PR China
| | - Chenglin Lu
- Weigao Orthopeadic Device Co. Ltd., Weihai, Shandong; PRChina
| | - Dwayne Arola
- Department of Mechanical Engineering; University of Maryland Baltimore County; Baltimore MD
- Department of Endodontics, Prosthodontics, and Operative Dentistry, Baltimore College of Dental Surgery; University of Maryland; Baltimore MD
| | - Dongsheng Zhang
- Department of Mechanics; Shanghai University; Shanghai PR China
- Shanghai Key Laboratory of Mechanics in Energy Engineering; Shanghai China
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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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Moszner N, Hirt T. New polymer-chemical developments in clinical dental polymer materials: Enamel-dentin adhesives and restorative composites. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/pola.26260] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Frassetto A, Navarra CO, Marchesi G, Turco G, Di Lenarda R, Breschi L, Ferracane JL, Cadenaro M. Kinetics of polymerization and contraction stress development in self-adhesive resin cements. Dent Mater 2012; 28:1032-9. [PMID: 22770674 DOI: 10.1016/j.dental.2012.06.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 04/27/2012] [Accepted: 06/14/2012] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The aim of the study was to evaluate the contraction stress, microhardness and polymerization kinetics of three self-adhesive cements vs. conventional dual-cure resin cement. METHODS Cements tested were: RelyX Unicem (3M ESPE, St. Paul, MN, USA), MaxCem Elite (Kerr, Orange, CA, USA), Clearfil SA Cement (Kuraray, Tokyo, Japan) and Duolink (Bisco Inc., Schaumburg, IL, USA). Cements were irradiated with a LED-curing unit (bluephase, IvoclarVivadent) for 20 or 40 s and the contraction forces (N) generated during polymerization were continuously recorded for 6 h with a universal testing machine. Polymerization kinetics were monitored using micro-Raman spectroscopy and degree of conversion was calculated. Vickers microhardness was also recorded. All measurements were performed at 10 min and 6h. Data were statistically analyzed by three-way ANOVA with repeated measures and Tukey's post hoc test (α=0.05). RESULTS Irrespective of exposure time, stress analysis ranked in the following order: Clearfil SA Cement<MaxCem<RelyX Unicem≤Duolink (p<0.05). Stress was correlated with microhardness values (p<0.05). Kinetic curves showed that maximum degree of conversion was attained more quickly than maximum stress after light activation. SIGNIFICANCE The conventional resin-based cement showed higher stress values than the self-adhesive cements. The results were material-dependent and probably correlated to the composition of each material.
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Affiliation(s)
- A Frassetto
- Department of Medical Sciences, University of Trieste, Italy
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Liu X, Li H, Li J, Lu P, Fok ASL. An acoustic emission study on interfacial debonding in composite restorations. Dent Mater 2011; 27:934-41. [DOI: 10.1016/j.dental.2011.05.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 04/22/2011] [Accepted: 05/18/2011] [Indexed: 11/26/2022]
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Price RB, Whalen JM, Price TB, Felix CM, Fahey J. The effect of specimen temperature on the polymerization of a resin-composite. Dent Mater 2011; 27:983-9. [PMID: 21798590 DOI: 10.1016/j.dental.2011.06.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 04/20/2011] [Accepted: 06/21/2011] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To use rapid scan FT-IR and Knoop microhardness to determine the effect of specimen temperature on the rate and extent of polymerization of a dental resin. METHODS Two-millimeter thick specimens of shade A2 Tetric EvoCeram were light cured for 20s at 22, 26, 30, and 35°C. The IR spectrum was obtained at the bottom of the specimens at a rate of 3 measurements per second for the first 5 min, and then again 2h later. The Knoop microhardness was measured at the bottom of the samples in the region where the IR spectrum was recorded at 5 min and 2h after light curing. Data were statistically analyzed using mixed model ANOVA (with Fisher's PLSD) to examine the effect of temperature, time and their interaction. The rate of conversion was determined using first differences and smoothed using a cubic spline procedure. RESULTS The bottom surfaces of the samples light cured at 22, 26, 30 and 35°C were all significantly different from each other (p<0.05). The higher temperature resulted in higher degree of conversion and Knoop microhardness values, and faster maximum rate of polymerization, which also occurred sooner. One second after the light was turned on, the rate of conversion was 106% faster at 35°C than at 22°C (p=0.003). Regression analysis showed a positive linear correlation between the degree of conversion and Knoop microhardness (r²=0.93). SIGNIFICANCE A relatively small difference in temperature can have a large and significant effect on the rate and extent of polymerization of dental resin. Consequently laboratory studies comparing the performance of resins should be conducted at clinically relevant temperatures.
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Affiliation(s)
- Richard B Price
- Department of Dental Clinical Sciences, Dalhousie University, Halifax, Nova Scotia, Canada.
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Takahashi H, Finger WJ, Wegner K, Utterodt A, Komatsu M, Wöstmann B, Balkenhol M. Factors influencing marginal cavity adaptation of nanofiller containing resin composite restorations. Dent Mater 2010; 26:1166-75. [DOI: 10.1016/j.dental.2010.08.189] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 02/01/2010] [Accepted: 08/27/2010] [Indexed: 11/17/2022]
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47
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Lien W, Vandewalle KS. Physical properties of a new silorane-based restorative system. Dent Mater 2010; 26:337-44. [DOI: 10.1016/j.dental.2009.12.004] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 11/25/2009] [Accepted: 12/03/2009] [Indexed: 10/20/2022]
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