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Ling L, Chen Y, Malyala R. Assessment of Degree of Conversion and Volumetric Shrinkage of Novel Self-Adhesive Cement. Polymers (Basel) 2024; 16:581. [PMID: 38475265 DOI: 10.3390/polym16050581] [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: 01/18/2024] [Revised: 02/10/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024] Open
Abstract
The degree of monomer conversion and polymerization shrinkage are two of the main reasons for potential adhesion failure between the tooth structure and the restoration substrate. To evaluate the degree of conversion and polymerization shrinkage of a newly developed self-adhesive resin cement, the degree of conversion (DC) was measured using FTIR under different activation modes, temperatures, and times. Volumetric shrinkage was tested using the AcuVol video imaging method. The experimental cement showed a higher DC than other cements under self-curing. The DC of the experimental cement was higher than that of other cements, except SpeedCem Plus under light curing. The experimental cement had a higher DC than other cements, except SpeedCem Plus in some conditions under dual curing. All self-adhesive cements had a higher DC at 37 °C than at 23 °C under self-curing, and there was no statistical difference between 23 °C and 37 °C under light curing. All self-adhesive cements showed a significantly higher DC at 10 min than at 5 min under self-curing. There was no statistical difference between 5 min and 10 min for most cements under dual curing. All self-adhesive cements statistically had the same volumetric shrinkage under light curing and self-curing. The newly developed self-adhesive resin cement exhibited a higher degree of conversion and similar volumetric shrinkage compared to these commercial self-adhesive resin cements.
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Affiliation(s)
- Long Ling
- Glidewell Dental, Irvine, CA 92612, USA
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Zhou W, Chen H, Weir MD, Oates TW, Zhou X, Wang S, Cheng L, Xu HH. Novel bioactive dental restorations to inhibit secondary caries in enamel and dentin under oral biofilms. J Dent 2023; 133:104497. [PMID: 37011782 DOI: 10.1016/j.jdent.2023.104497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 04/03/2023] Open
Abstract
OBJECTIVE To provide the first review on cutting-edge research on the development of new bioactive restorations to inhibit secondary caries in enamel and dentin under biofilms. State-of-the-art bioactive and therapeutic materials design, structure-property relationships, performance and efficacies in oral biofilm models. DATA, SOURCES AND STUDY SELECTION Researches on development and assessment new secondary caries inhibition restorations via in vitro and in vivo biofilm-based secondary caries models were included. The search of articles was carried out in Web of Science, PubMed, Medline and Scopus. CONCLUSIONS Based on the found articles, novel bioactive materials are divided into different categories according to their remineralization and antibacterial biofunctions. In vitro and in vivo biofilm-based secondary caries models are effective way of evaluating the materials efficacies. However, new intelligent and pH-responsive materials were still urgent need. And the materials evaluation should be performed via more clinical relevant biofilm-based secondary caries models. CLINICAL SIGNIFICANCE Secondary caries is a primary reason for dental restoration failures. Biofilms produce acids, causing demineralization and secondary caries. To inhibit dental caries and improve the health and quality of life for millions of people, it is necessary to summarize the present state of technologies and new advances in dental biomaterials for preventing secondary caries and protecting tooth structures against oral biofilm attacks. In addition, suggestions for future studies are provided.
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Kasraei S, Haghi S, Farzad A, Malek M, Nejadkarimi S. Comparative of flexural strength, hardness, and fluoride release of two bioactive restorative materials with RMGI and composite resin. BRAZILIAN JOURNAL OF ORAL SCIENCES 2022. [DOI: 10.20396/bjos.v21i00.8665263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Aim: This study was fulfilled to evaluate the flexural strength, micro-hardness, and release of two fluoride ions of bioactive restorative materials (Cention N and Activa Bioactive), a resin modified glass ionomer (Fuji II LC), and a resin composite (Filtek z250). Methods: Forty samples from four restorative materials (Activa Bioactive, Fuji II LC, Cention N, and Filtek Z250) were provided according to the current standards of ISO 4049/2000 guide lines. Subsequently, the samples were stored for 24 hours and 6 months in artificial saliva, and successively, flexural strength and micro-hardness of the samples were measured. For each studied groups the pH was decreased from 6.8 to 4 in storage solution. The rate of changes in fluoride ion release was measured after three different storage periods of 24 hours, 48 hours, and 6 months in distilled water, according to the previous studies’ method. Two-way ANOVA, One-way ANOVA, Tukey HSD Pair wise comparisons, and independent t-tests were used to analyze data (α= 0.05). Results: The highest flexural strength and surface micro-hardness after 24 hours and also after 6 month were observed for Cention N(p<0.001).Flexural strength of all samples stored for 6 months was significantly lower than the samples stored for 24 hours(p<0.001). The accumulative amount of the released fluoride ion in RMGI, after six-month storage period in distilled water was considerably higher (p<0.001) than 24 hours and 48 hours storage. The amount of fluoride ion release with increasing acidity of the environment (from pH 6.8 to 4) in Fuji II LC glass ionomer was higher than the bioactive materials (p<0.05). Conclusion: The flexural strength of RMGI was increased after storage against the Activa Bioactive,Cention N and Z250 composite. Storage of restorative materials in artificial saliva leads to a significant reduction in micro hardness. The behavior and amount of released fluoride ions in these restorative materials, which are stored in an acidic environment, were dependent on the type of restorative material.
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The Influence of Low-Molecular-Weight Monomers (TEGDMA, HDDMA, HEMA) on the Properties of Selected Matrices and Composites Based on Bis-GMA and UDMA. MATERIALS 2022; 15:ma15072649. [PMID: 35407980 PMCID: PMC9000443 DOI: 10.3390/ma15072649] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 01/05/2023]
Abstract
Bisphenol A-glycidyl methacrylate (bis-GMA) and urethane dimethacrylate (UDMA) are usually combined with low-viscosity monomers to obtain more desirable viscosity, handling characteristics and general properties. The present study determined the flexural strength (FS), flexural modulus (FM), diametral tensile strength (DTS), and hardness (HV) of five matrices and composites based on these resins. The polymerization shrinkage stress (PSS) was also studied for the composites. The polymer matrices were formed using bis-GMA and UDMA. TEGDMA, HEMA and HDDMA acted as co-monomers. The composites had 45 wt.% of filler content. The highest FS and FM were obtained from the UDMA/bis-GMA/TEGDMA/HEMA matrix and the composite (matrix + filler). The best DTS values were obtained from the UDMA/bis-GMA/HEMA matrix and the composite. One of the lowest values of FS, FM, and DTS was obtained from the UDMA/bis-GMA/HDDMA matrix and the composite. All the composites demonstrated similar hardness values. The lowest polymerization shrinkage stress was observed for the UDMA/bis-GMA/TEGDMA/HEMA composite, and the highest PSS was observed for the UDMA/bis-GMA/TEGDMA/HDDMA composite. The addition of HEMA had a positive effect on the properties of the tested materials, which may be related to the improved mobility of the bis-GMA and UDMA monomers.
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Monteferrante M, Tiribocchi A, Succi S, Pisignano D, Lauricella M. Capturing Free-Radical Polymerization by Synergetic Ab Initio Calculations and Topological Reactive Molecular Dynamics. Macromolecules 2022; 55:1474-1486. [PMID: 35287293 PMCID: PMC8909409 DOI: 10.1021/acs.macromol.1c01408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/08/2021] [Indexed: 11/30/2022]
Abstract
Photocurable polymers are used ubiquitously in 3D printing, coatings, adhesives, and composite fillers. In the present work, the free radical polymerization of photocurable compounds is studied using reactive classical molecular dynamics combined with a dynamical approach of the nonequilibrium molecular dynamics (D-NEMD). Different concentrations of radicals and reaction velocities are considered. The mechanical properties of the polymer resulting from 1,6-hexanediol dimethacrylate systems are characterized in terms of viscosity, diffusion constant, and activation energy, whereas the topological ones through the number of cycles (polymer loops) and cyclomatic complexity. Effects like volume shrinkage and delaying of the gel point for increasing monomer concentration are also predicted, as well as the stress-strain curve and Young's modulus. Combining ab initio, reactive molecular dynamics, and the D-NEMD method might lead to a novel and powerful tool to describe photopolymerization processes and to original routes to optimize additive manufacturing methods relying on photosensitive macromolecular systems.
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Affiliation(s)
| | - Adriano Tiribocchi
- Istituto
per le Applicazioni del Calcolo CNR, Via dei Taurini 19, 00185 Rome, Italy
| | - Sauro Succi
- Istituto
per le Applicazioni del Calcolo CNR, Via dei Taurini 19, 00185 Rome, Italy,Center
for Life Nano Science@La Sapienza, Istituto
Italiano di Tecnologia, Viale Regina Elena, 291, 00161 Rome, Italy
| | - Dario Pisignano
- Dipartimento
di Fisica, Università di Pisa, Largo B. Pontecorvo 16 3, 56127 Pisa, Italy,NEST,
Istituto Nanoscienze-CNR, Piazza S. Silvestro 12, 56127 Pisa, Italy
| | - Marco Lauricella
- Istituto
per le Applicazioni del Calcolo CNR, Via dei Taurini 19, 00185 Rome, Italy,
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A Novel Low-Shrinkage Resin for 3D Printing. J Dent 2022; 118:103957. [PMID: 35038476 DOI: 10.1016/j.jdent.2022.103957] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 01/08/2022] [Accepted: 01/12/2022] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE To evaluate the shrinkage, accuracy, and mechanical properties of a newly developed photo-polymerizable resin material for 3D printing dental applications and compare it with three commercially available resins. METHODS An experimental novel proprietary resin material for 3D printing was formulated. This new resin, Die and Model Tan (SprintRay), Formlabs Grey (FormLabs), and LCD Grey (Roxel 3D) were evaluated and tested for volumetric shrinkage, accuracy, and flexural and tensile properties. Volumetric shrinkage was measured using the AcuVol video imaging method. The accuracy of the 3D printed objects through the DLP (digital light processing) printing system was determined by the 3D deviation between the scanned model and the original CAD digital model. Parallelepiped specimens (2 × 2 × 25 mm, n= 5) were printed for flexural strength, flexural modulus, and modulus of resilience and measured in accordance with ISO-4049. Dumbbell-shaped specimens (Type V, n = 5) were printed to investigate the tensile strength and tested according to ASTM-D638. Data were analyzed using one-way ANOVA and post-hoc Tukey tests (p≤0.05). RESULTS The experimental resin exhibited significantly lower volumetric shrinkage and significantly higher accuracy than the other commercially available resins (p < 0.001). The experimental resin showed flexural strength, flexural modulus, and tensile strength similar to Die and Model Tan resin (SprintRay) (p > 0.05), and these parameters were significantly higher than those of Formlabs Grey resin (Formlabs) and lower than those of LCD Gray resin (Roxel3D)(p <0.001). CONCLUSION The newly formulated 3D printing resin demonstrated lower volumetric shrinkage, high accuracy, and adequate mechanical properties compared to the commercially available resin materials. CLINICAL SIGNIFICANCE The new 3D printed objects exhibited higher accuracy, good stability over time, and adequate mechanical properties. The new 3D printing resin is a good candidate for modeling applications for restoration, orthodontics and implants.
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Lai CC, Lin CP, Wang YL. Development of antibacterial composite resin containing chitosan/fluoride microparticles as pit and fissure sealant to prevent caries. J Oral Microbiol 2021; 14:2008615. [PMID: 34992735 PMCID: PMC8725701 DOI: 10.1080/20002297.2021.2008615] [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: 08/04/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Develop a fissure sealant containing chitosan/fluoride microparticles (C/F) with antibacterial, fluoride release and recharge ability. MATERIALS AND METHODS Chitosan/fluoride microparticles were synthesized and added to Bis-GMA as C/F. The experimental group comprised 0%, 2%, 4% C/F, with ClinproTM fissure sealant as control. Antibacterial activity was detected by Alamar Blue assay and colony-forming units (CFU). Biocompatibility was determined by WST-1 and LDH test. Curing depth, flowability, tensile strength and flexural strength were measured according to the ISO standard; microhardness by Vickers hardness test. Fluoride release and recharge were recorded through ionic chromatography. Statistical analysis was performed with an independent t-test, one-way and two-way ANOVA. P values less than 0.05 were considered significant. RESULTS 2% and 4% C/F showed antibacterial ability with CFU ratios decreasing to 10% and 25% respectively (P < 0.01). Nonetheless, 4% C/F was concerned because biocompatibility revealed cytotoxicity compared to medium (P < 0.001). 2% C/F had superior mechanical properties to ClinproTM fissure sealant in terms of curing depth (P < 0.001), microhardness and tensile strength (P < 0.01). It had good fluoride release and recharge ability (P = 0.67). CONCLUSIONS 2% C/F could be an antibacterial sealant with good mechanical strength, fluoride release and recharge ability.
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Affiliation(s)
- Chun-Cheng Lai
- Pediatric Dentistry, Far Eastern Memorial Hospital, Taipei, Taiwan
- Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan
| | - Chun-Pin Lin
- Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan
- College of Medicine, National Taiwan University Hospital, National Taiwan University, Taipei, Taiwan
| | - Yin-Lin Wang
- Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan
- College of Medicine, National Taiwan University Hospital, National Taiwan University, Taipei, Taiwan
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Dai Q, Weir MD, Ruan J, Liu J, Gao J, Lynch CD, Oates TW, Li Y, Chang X, Xu HHK. Effect of co-precipitation plus spray-drying of nano-CaF 2 on mechanical and fluoride properties of nanocomposite. Dent Mater 2021; 37:1009-1019. [PMID: 33879343 DOI: 10.1016/j.dental.2021.03.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 01/20/2021] [Accepted: 03/28/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Fluoride (F)-releasing restoratives typically are either weak mechanically or release only low levels of F ions. The objectives of this study were to: (1) develop a novel photo-cured nanocomposite with strong mechanical properties and high levels of sustained F ion release via a two-step "co-precipitation + spray-drying" technique to synthesize CaF2 nanoparticles (nCaF2); and (2) investigate the effect of spray-drying treatment after co-precipitation of nCaF2 on mechanical properties and F ion release of composite. METHODS Two types of CaF2 particles were synthesized: A co-precipitation method yielded CaF2cp; "co-precipitation + spray-drying" yielded nCaF2cpsd. Composites were fabricated with fillers of: (1) 0% CaF2 + 70% glass; (2) 10% CaF2cp + 60% glass; (3) 15% CaF2cp + 55% glass; (4) 20% CaF2cp + 50% glass; (5) 10% nCaF2cpsd + 60% glass; (6) 15% nCaF2cpsd + 55% glass; and (7) 20% nCaF2cpsd + 50% glass. A commercial F-releasing nanocomposite served as control. RESULTS The nCaF2cpsd had much smaller particle size (median = 32 nm) and narrower distribution (22-57 nm) than CaF2cp (median = 5.25 μm, 162 nm-67 μm). The composite containing nCaF2cpsd had greater flowability, flexural strength, elastic modulus and hardness than CaF2cp composite and commercial control composite. At 84-day immersion in water, the nanocomposites containing 20% nCaF2cpsd had 65 times higher cumulative F release, and 77 times greater long-term F-release rate, than commercial control. CONCLUSIONS A novel two-step "co-precipitation + spray-drying" technique of synthesizing nCaF2 was developed. The photo-cured nanocomposite containing 20% nCaF2cpsd possessed strong mechanical properties and excellent long-term F-release ability, and hence is promising for dental restoration applications to inhibit secondary caries.
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Affiliation(s)
- Quan Dai
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA
| | - Michael D Weir
- Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA
| | - Jianping Ruan
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Jin Liu
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA
| | - Jianghong Gao
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China; Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA
| | - Christopher D Lynch
- Restorative Dentistry, University Dental School and Hospital, University College Cork, Wilton, Cork, Ireland
| | - Thomas W Oates
- Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA
| | - Yuncong Li
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China.
| | - Xiaofeng Chang
- Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Diseases, Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China.
| | - Hockin H K Xu
- Department of Advanced Oral Sciences and Therapeutics, School of Dentistry, University of Maryland, Baltimore, MD 21021, USA; Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA; Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
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Bastos NA, Bitencourt SB, Martins EA, De Souza GM. Review of nano-technology applications in resin-based restorative materials. J ESTHET RESTOR DENT 2020; 33:567-582. [PMID: 33368974 DOI: 10.1111/jerd.12699] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 12/09/2020] [Accepted: 12/14/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Nanotechnology has progressed significantly and particles as small as 3 nm are being employed in resin-based restorative materials to improve clinical performance. The goal of this review is to report the progress of nanotechnology in Restorative Dentistry by reviewing the advantages, limitations, and applications of resin-based restorative materials with nanoparticles. MATERIALS AND METHODS A literature review was conducted using PubMed/Medline, Scopus and Embase databases. In vitro, in vivo and in situ research studies published in English between 1999 and 2020, and which focused on the analysis of resin-based restorative materials containing nanoparticles were included. RESULTS A total of 140 studies were included in this review. Studies reported the effect of incorporating different types of nanoparticles on adhesive systems or resin composites. Mechanical, physical, and anti-bacterial properties were described. The clinical performance of resin-based restorative materials with nanoparticles was also reported. CONCLUSIONS The high surface area of nanoparticles exponentially increases the bioactivity of materials using bioactive nanofillers. However, the tendency of nanoparticles to agglomerate, the chemical instability of the developed materials and the decline of rheological properties when high ratios of nanoparticles are employed are some of the obstacles to overcome in the near future. CLINICAL SIGNIFICANCE In spite of the recent advancements of nanotechnology in resin-based restorative materials, some challenges need to be overcome before new nano-based restorative materials are considered permanent solutions to clinical problems.
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Affiliation(s)
- Natalia Almeida Bastos
- Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, Brazil
| | - Sandro Basso Bitencourt
- Department of Dental Materials and Prosthodontics, Sao Paulo State University (UNESP), Araçatuba, Brazil
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ZHANG N, XIE C. Polymerization shrinkage, shrinkage stress, and mechanical evaluation of novel prototype dental composite resin. Dent Mater J 2020; 39:1064-1071. [DOI: 10.4012/dmj.2019-286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Na ZHANG
- Department of Endodontics, School of Stomatology, Wannan Medical College
| | - Chao XIE
- Department of Oral Implantology, School of Stomatology, Fourth Military Medical University
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Tu J, Makarian K, Alvarez NJ, Palmese GR. Formulation of a Model Resin System for Benchmarking Processing-Property Relationships in High-Performance Photo 3D Printing Applications. MATERIALS 2020; 13:ma13184109. [PMID: 32947908 PMCID: PMC7560343 DOI: 10.3390/ma13184109] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/08/2020] [Accepted: 09/14/2020] [Indexed: 12/26/2022]
Abstract
A well-defined resin system is needed to serve as a benchmark for 3D printing of high-performance composites. This work describes the design and characterization of such a system that takes into account processability and performance considerations. The Grunberg-Nissan model for resin viscosity and the Fox equation for polymer Tg were used to determine proper monomer ratios. The target viscosity of the resin was below 500 cP, and the target final Tg of the cured polymer was 150 °C based on tan-δ peak from dynamic mechanical analysis. A tri-component model resin system, termed DA-2 resin, was determined and fully characterized. The printed polymer post-cure exhibited good thermal properties and high mechanical strength, but has a comparatively low fracture toughness. The model resin will be used in additive manufacturing of fiber reinforced composite materials as well as for understanding the fundamental processing-property relationships in light-based 3D printing.
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Kaawar Z, Paulus B. Adsorption of hydrogen fluoride on alkaline earth fluoride surfaces: A first-principles study. J Fluor Chem 2019. [DOI: 10.1016/j.jfluchem.2018.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Dental Resin Cements-The Influence of Water Sorption on Contraction Stress Changes and Hydroscopic Expansion. MATERIALS 2018; 11:ma11060973. [PMID: 29890684 PMCID: PMC6025551 DOI: 10.3390/ma11060973] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/05/2018] [Accepted: 06/06/2018] [Indexed: 11/16/2022]
Abstract
Resin matrix dental materials undergo contraction and expansion changes due to polymerization and water absorption. Both phenomena deform resin-dentin bonding and influence the stress state in restored tooth structure in two opposite directions. The study tested three composite resin cements (Cement-It, NX3, Variolink Esthetic DC), three adhesive resin cements (Estecem, Multilink Automix, Panavia 2.0), and seven self-adhesive resin cements (Breeze, Calibra Universal, MaxCem Elite Chroma, Panavia SA Cement Plus, RelyX U200, SmartCem 2, and SpeedCEM Plus). The stress generated at the restoration-tooth interface during water immersion was evaluated. The shrinkage stress was measured immediately after curing and after 0.5 h, 24 h, 72 h, 96 h, 168 h, 240 h, 336 h, 504 h, 672 h, and 1344 h by means of photoelastic study. Water sorption and solubility were also studied. All tested materials during polymerization generated shrinkage stress ranging from 4.8 MPa up to 15.1 MPa. The decrease in shrinkage strain (not less than 57%) was observed after water storage (56 days). Self-adhesive cements, i.e., MaxCem Elite Chroma, SpeedCem Plus, Panavia SA Plus, and Breeze exhibited high values of water expansion stress (from 0 up to almost 7 MPa). Among other tested materials only composite resin cement Cement It and adhesive resin cement Panavia 2.0 showed water expansion stress (1.6 and 4.8, respectively). The changes in stress value (decrease in contraction stress or built up of hydroscopic expansion) in time were material-dependent.
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Kaawar Z, Mahn S, Kemnitz E, Paulus B. On the Morphology of Group II Metal Fluoride Nanocrystals at Finite Temperature and Partial Pressure of HF. Molecules 2017; 22:molecules22040663. [PMID: 28430134 PMCID: PMC6154342 DOI: 10.3390/molecules22040663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/03/2017] [Accepted: 04/14/2017] [Indexed: 11/16/2022] Open
Abstract
We have investigated the bulk and surface properties of the group II metal fluorides CaF2, SrF2 and BaF2 using periodic density functional theory (DFT) calculations and surface thermodynamics. Our bulk results show that the best agreement with experiment is achieved with the B3LYP and PBE functionals. We determined the relative importance of the low index surfaces in vacuum and found that an fluoride microcrystal exposes only the (111) surface in which the undercoordinated cations are sevenfold coordinated. With methods of ab initio surface thermodynamics, we analyzed the stability of different surfaces under hydrogen fluoride (HF) pressure and determined the presumable shape of the crystals with respect to different HF concentrations and temperatures. In the case of CaF2 and SrF2, the calculated shapes of the crystals agree well with TEM images of fluorolytic sol-gel synthesized nanocrystals at room temperature and high HF concentration.
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Affiliation(s)
- Zeinab Kaawar
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.
| | - Stefan Mahn
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - Erhard Kemnitz
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - Beate Paulus
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.
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Esthetic judgments of palatally displaced canines 3 months postdebond after surgical exposure with either a closed or an open technique. Am J Orthod Dentofacial Orthop 2015; 147:173-81. [DOI: 10.1016/j.ajodo.2014.10.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 10/01/2014] [Accepted: 10/01/2014] [Indexed: 11/17/2022]
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Ilie N, Stark K. Effect of different curing protocols on the mechanical properties of low-viscosity bulk-fill composites. Clin Oral Investig 2014; 19:271-9. [DOI: 10.1007/s00784-014-1262-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 05/13/2014] [Indexed: 11/25/2022]
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17
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Schmidt L, Emmerling F, Kirmse H, Kemnitz E. Sol–gel synthesis and characterisation of nanoscopic strontium fluoride. RSC Adv 2014. [DOI: 10.1039/c3ra43769h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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18
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Melo MAS, Guedes SFF, Xu HHK, Rodrigues LKA. Nanotechnology-based restorative materials for dental caries management. Trends Biotechnol 2013; 31:459-67. [PMID: 23810638 PMCID: PMC3845439 DOI: 10.1016/j.tibtech.2013.05.010] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 05/24/2013] [Accepted: 05/28/2013] [Indexed: 11/29/2022]
Abstract
Nanotechnology has been applied to dental materials as an innovative concept for the development of materials with better properties and anticaries potential. In this review we discuss the current progress and future applications of functional nanoparticles incorporated in dental restorative materials as useful strategies to dental caries management. We also overview proposed antimicrobial and remineralizing mechanisms. Nanomaterials have great potential to decrease biofilm accumulation, inhibit the demineralization process, to be used for remineralizing tooth structure, and to combat caries-related bacteria. These results are encouraging and open the doors to future clinical studies that will allow the therapeutic value of nanotechnology-based restorative materials to be established.
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Affiliation(s)
- Mary A S Melo
- Biomaterials & Tissue Engineering Division, Dept of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, USA.
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19
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Chien JM, Chou CT, Lu YC, Lu T, Chi CC, Tseng LL, Liu SI, Cheng JS, Kuo CC, Liang WZ, Jan CR. Effect of the environmental pollutant bisphenol A dimethacylate (BAD) on Ca2+ movement and viability in OC2 human oral cancer cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2013; 35:178-184. [PMID: 23318710 DOI: 10.1016/j.etap.2012.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 11/24/2012] [Accepted: 12/14/2012] [Indexed: 06/01/2023]
Abstract
The environmental pollutant bisphenol A dimethacylate (BAD) has been used as a dental composite. The effect of BAD on cytosolic Ca(2+) concentrations ([Ca(2+)]i) and viability in OC2 human oral cancer cells was explored. The Ca(2+)-sensitive fluorescent dye fura-2 was applied to measure [Ca(2+)]i. BAD induced [Ca(2+)]i rises in a concentration-dependent manner. The response was reduced by removing extracellular Ca(2+). BAD-evoked Ca(2+) entry was suppressed by nifedipine, econazole, and SK&F96365. In Ca(2+)-free medium, incubation with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin abolished BAD-induced [Ca(2+)]i rise. Inhibition of phospholipase C with U73122 did not alter BAD-induced [Ca(2+)]i rise. At 10-30μM, BAD inhibited cell viability, which was not reversed by chelating cytosolic Ca(2+). BAD (20-30μM) also induced apoptosis. Collectively, in OC2 cells, BAD induced a [Ca(2+)]i rise by evoking phospholipase C-independent Ca(2+) release from the endoplasmic reticulum and Ca(2+) entry via store-operated Ca(2+) channels. BAD also caused apoptosis.
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Affiliation(s)
- Jau-Min Chien
- Department of Pediatrics, Ping Tung Christian Hospital, Ping Tung 900, Taiwan
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20
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Fan Y, Townsend J, Wang Y, Lee EC, Evans K, Hender E, Hagan JL, Xu X. Formulation and characterization of antibacterial fluoride-releasing sealants. Pediatr Dent 2013; 35:E13-E18. [PMID: 23635887 PMCID: PMC3644993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PURPOSE The purpose of this study was to formulate and characterize experimental antibacterial fluoride-releasing sealants and compare them with commercial sealants for fluoride release, recharge, adhesion, and microleakage. METHODS Two experimental sealants (Exp-1, Exp-2) containing a synthesized antibacterial fluoride-releasing monomer and fluoride-releasing filler were formulated. Exp-2 also contained NovaMin nanoparticles. Commercial sealants Clinpro (CL) FluroShield (FS), and SeLECT Defense (E34) were also included. Fluoride release from disk samples in deionized water was measured daily using an ion-selective electrode for 14 days, and after recharging with Neutra-Foam (2.0% sodium fluoride), fluoride was measured for 5 days. Microtensile bonding strengths (MTBS) to enamel were tested after 24-hour storage in water at 37°C or thermocycling 5-55°C for 1,000 cycles. A microleakage test was conducted on extracted teeth using a dye-penetration method. The data were analyzed using analysis of variance with the Tukey's honestly significant difference test and Kruskal-Wallis test. RESULTS Exp-1 and Exp-2 had significantly higher fluoride release and recharge capabilities than CL and FL (P<.05). All tested sealants had similar MTBS before and after thermocycling. Exp-2 and Exp-1 had significantly lower microleakage scores (P<.05) than other groups. CONCLUSION The experimental sealants had higher fluoride release and recharge capabilities and similar or better retention than commercial sealants.
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Affiliation(s)
- Yuwei Fan
- Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, La., USA
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22
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Wang Y, Samoei GK, Lallier TE, Xu X. Synthesis and Characterization of New Antibacterial Fluoride-Releasing Monomer and Dental Composite. ACS Macro Lett 2012; 2:59-62. [PMID: 23336090 DOI: 10.1021/mz300579y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A new dimethacrylate chelating monomer containing a BisGMA-like backbone structure and a bis(carboxymethyl)-L-lysine chelating group and its ternary zirconium-fluoride complex (antibacterial fluoride-releasing monomer) have been synthesized. The monomer structures were confirmed by (1)H-NMR, (13)C-NMR, and ES-MS analysis. Several experimental fluoride-releasing dental composites containing different quantities of the new antibacterial fluoride-releasing monomer were formulated and tested for fluoride release, fluoride recharge, compressive and flexural strengths, water sorption and solubility. These composites displayed high fluoride release and recharge capabilities, as well as good physical and mechanical properties.
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Affiliation(s)
- Yapin Wang
- Department
of Comprehensive Dentistry and
Biomaterials, Louisiana State University Health Science, School of Dentistry, 1100 Florida Avenue,
New Orleans, Louisiana 70119, United States
| | - George K. Samoei
- Department
of Comprehensive Dentistry and
Biomaterials, Louisiana State University Health Science, School of Dentistry, 1100 Florida Avenue,
New Orleans, Louisiana 70119, United States
| | - Thomas E. Lallier
- Department
of Comprehensive Dentistry and
Biomaterials, Louisiana State University Health Science, School of Dentistry, 1100 Florida Avenue,
New Orleans, Louisiana 70119, United States
| | - Xiaoming Xu
- Department
of Comprehensive Dentistry and
Biomaterials, Louisiana State University Health Science, School of Dentistry, 1100 Florida Avenue,
New Orleans, Louisiana 70119, United States
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23
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Xu X, Wang Y, Liao S, Wen ZT, Fan Y. Synthesis and characterization of antibacterial dental monomers and composites. J Biomed Mater Res B Appl Biomater 2012; 100:1151-62. [PMID: 22447582 DOI: 10.1002/jbm.b.32683] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 12/22/2011] [Accepted: 01/02/2012] [Indexed: 11/08/2022]
Abstract
The objective of this study is to synthesize antibacterial methacrylate and methacrylamide monomers and formulate antibacterial fluoride-releasing dental composites. Three antibacterial methacrylate or methacrylamide monomers containing long-chain quaternary ammonium fluoride, 1,2-methacrylamido-N,N,N-trimethyldodecan-1-aminium fluoride (monomer I), N-benzyl-11-(methacryloyloxy)-N,N-dimethylundecan-1-aminium fluoride (monomer II), and methacryloxyldecylpyridinium fluoride (monomer III) have been synthesized and analyzed by nuclear magnetic resonance (NMR) and mass spectrometry (MS). The cytotoxicity test and bactericidal test against Streptococcus mutans indicate that antibacterial monomer II is superior to monomers I and III. A series of dental composites containing 0-6% of antibacterial monomer II have been formulated and tested for degree of conversion (DC), flexure strength, water sorption, solubility, and inhibition of S. mutans biofilms. An antibacterial fluoride-releasing dental composite has also been formulated and tested for flexure strength and fluoride release. The dental composite containing 3% of monomer II has a significant effect against S. mutans biofilm formation without major adverse effects on its physical and mechanical properties. The new antibacterial monomers can be used together with the fluoride-releasing monomers containing a ternary zirconiun-fluoride chelate to formulate a new antibacterial fluoride-releasing dental composite. Such a new dental composite is expected to have higher anticaries efficacy and longer service life.
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Affiliation(s)
- Xiaoming Xu
- Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, School of Dentistry, New Orleans, Louisiana 70119, USA.
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Nanocomposite containing CaF(2) nanoparticles: thermal cycling, wear and long-term water-aging. Dent Mater 2012; 28:642-52. [PMID: 22429937 DOI: 10.1016/j.dental.2012.02.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 02/16/2012] [Accepted: 02/17/2012] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Fluoride (F) releasing dental restoratives are promising to promote remineralization and combat caries. The objectives of this study were to develop nanocomposite containing calcium fluoride nanoparticles (nCaF(2)), and to investigate the long-term mechanical durability including wear, thermal-cycling and long-term water-aging behavior. METHODS Two types of fillers were used: nCaF(2) with a diameter of 53 nm, and glass particles of 1.4 μm. Four composites were fabricated with fillers of: (1) 0% nCaF(2)+65% glass; (2) 10% nCaF(2)+55% glass; (3) 20% nCaF(2)+45% glass; (4) 30% nCaF(2)+35% glass. Three commercial materials were also tested. Specimens were subjected to thermal-cycling between 5°C and 60°C for 10(5) cycles, three-body wear for 4×10(5) cycles, and water-aging for 2 years. RESULTS After thermal-cycling, the nCaF(2) nanocomposites had flexural strengths in the range of 100-150 MPa, five times higher than the 20-30 MPa for resin-modified glass ionomer (RMGI). The wear scar depth showed an increasing trend with increasing nCaF(2) filler level. Wear of nCaF(2) nanocomposites was within the range of wear for commercial controls. Water-aging decreased the strength of all materials. At 2 years, flexural strength was 94 MPa for nanocomposite with 10% nCaF(2), 60 MPa with 20% nCaF(2), and 48 MPa with 30% nCaF(2). They are 3-6 fold higher than the 15 MPa for RMGI (p<0.05). SEM revealed air bubbles and cracks in a RMGI, while composite control and nCaF(2) nanocomposites appeared dense and solid. SIGNIFICANCE Combining nCaF(2) with glass particles yielded nanocomposites with long-term mechanical properties that were comparable to those of a commercial composite with little F release, and much better than those of RMGI controls. These strong long-term properties, together with their F release being comparable to RMGI as previously reported, indicate that the nCaF(2) nanocomposites are promising for load-bearing and caries-inhibiting restorations.
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25
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In vitro comparison of mechanical properties and degree of cure of bulk fill composites. Clin Oral Investig 2012; 17:227-35. [DOI: 10.1007/s00784-012-0702-8] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 02/21/2012] [Indexed: 11/28/2022]
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Use of NIR light and upconversion phosphors in light-curable polymers. Dent Mater 2012; 28:304-11. [DOI: 10.1016/j.dental.2011.11.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 11/22/2011] [Indexed: 11/18/2022]
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Guo G, Fan Y, Zhang JF, Hagan JL, Xu X. Novel dental composites reinforced with zirconia-silica ceramic nanofibers. Dent Mater 2011; 28:360-8. [PMID: 22153326 DOI: 10.1016/j.dental.2011.11.006] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 08/30/2011] [Accepted: 11/07/2011] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To fabricate and characterize dental composites reinforced with various amounts of zirconia-silica (ZS) or zirconia-yttria-silica (ZYS) ceramic nanofibers. METHODS Control composites (70 wt% glass particle filler, no nanofibers) and experimental composites (2.5, 5.0, and 7.5 wt% ZS or ZYS nanofibers replacing glass particle filler) were prepared by blending 29 wt% dental resin monomers, 70 wt% filler, and 1.0 wt% initiator, and polymerized by either heat or dental curing light. Flexural strength (FS), flexural modulus (FM), energy at break (EAB), and fracture toughness (FT) were tested after the specimens were stored in 37°C deionized water for 24h, 3 months, or 6 months. Degree of conversion (DC) of monomers in composites was measured using Fourier transformed near-infrared (FT-NIR) spectroscopy. Fractured surfaces were observed by field-emission scanning electron microscope (FE-SEM). The data were analyzed using ANOVA with Tukey's Honestly Significant Differences test used for post hoc analysis. RESULTS Reinforcement of dental composites with ZS or ZYS nanofibers (2.5% or 5.0%) can significantly increase the FS, FM and EAB of dental composites over the control. Further increase the content of ZS nanofiber (7.5%), however, decreases these properties (although they are still higher than those of the control). Addition of nanofibers did not decrease the long-term mechanical properties of these composites. All ZS reinforced composites (containing 2.5%, 5.0% and 7.5% ZS nanofibers) exhibit significantly higher fracture toughness than the control. The DC of the composites decreases with ZS nanofiber content. SIGNIFICANCE Incorporation of ceramic nanofibers in dental composites can significantly improve their mechanical properties and fracture toughness and thus may extend their service life.
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Affiliation(s)
- Guangqing Guo
- Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, School of Dentistry, New Orleans, LA 70119, USA
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28
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Benson PE. Fluoride-Containing Materials and the Prevention of Demineralization During Orthodontic Treatment—Which Research Method Should We Now Use? Semin Orthod 2010. [DOI: 10.1053/j.sodo.2010.06.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Moreau JL, Xu HHK. Fluoride releasing restorative materials: Effects of pH on mechanical properties and ion release. Dent Mater 2010; 26:e227-35. [PMID: 20708253 DOI: 10.1016/j.dental.2010.07.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 07/07/2010] [Indexed: 12/21/2022]
Abstract
OBJECTIVES Secondary caries and restorative fracture are the two main reasons for restoration failures. Fluoride ion (F) release can help inhibit caries. Plaque pH after a sucrose rinse can decrease to a cariogenic pH of 4-4.5. The objective of this study was to investigate the effects of solution pH and immersion time on the mechanical properties and F release of restorative materials. METHODS Three resin-modified glass ionomers (Viremer, Fuji II LC, Ketac Nano), one compomer (Dyract Flow), and one composite (Heliomolar), were tested. Flexural strength and elastic modulus were measured before and after 84d of immersion in solutions of pH 4, 5.5, and 7. F release was measured as a function of pH and immersion time. RESULTS Immersion and material type had significant effects on mechanical properties. Vitremer had a flexural strength (mean±sd; n=6) of 99±25MPa before immersion; it decreased to 32±9MPa after 84d of immersion (p<0.05). In comparison, Heliomolar had a smaller strength loss, decreasing from 99±9MPa to 65±7MPa (p<0.05). Solution pH had little effect on mechanical properties. For example, Fuji II LC had a strength of 63±15MPa at pH 4, similar to 61±30MPa at pH 5.5, and 56±22MPa at pH 7 (p>0.1). In contrast, solution pH had a significant effect on F release. F release at 84d for Fuji was 609±25μg/cm(2) at pH 4, much higher than 258±36μg/cm(2) at pH 5.5, and 188±9μg/cm(2) at pH 7. SIGNIFICANCE The restoratives tested were able to greatly increase the F release at acidic, cariogenic pH, when these ions are most needed to inhibit caries. However, mechanical properties of these F-releasing restoratives degraded significantly in immersion. Efforts are needed to develop F-releasing restoratives with high levels of sustained F release, as well as improved durability of mechanical properties for large stress-bearing restorations.
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Affiliation(s)
- Jennifer L Moreau
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, MD 21201, United States
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Xu HHK, Moreau JL, Sun L, Chow LC. Novel CaF(2) nanocomposite with high strength and fluoride ion release. J Dent Res 2010; 89:739-45. [PMID: 20439933 DOI: 10.1177/0022034510364490] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Secondary caries and restoration fracture remain common problems in dentistry. This study tested the hypothesis that combining nano-CaF(2) and glass fillers would yield nanocomposites with high mechanical properties and F release. Novel CaF(2) nanoparticles (56-nm) were synthesized via spray-drying and incorporated into resin. F release increased with increasing the nano-CaF(2) content, or with decreasing pH (p < 0.05). F-release rates at 70-84 days were 1.13 microg/(cm(2) x day) and 0.50 microg/(cm(2) x day) for nanocomposites containing 30% and 20% nano-CaF(2), respectively. They matched the 0.65 microg/(cm(2) x day) of resin-modified glass ionomer (p > 0.1). The nanocomposites had flexural strengths of 70-120 MPa, after 84-day immersion at pH 4, pH 5.5, and pH 7. These strengths were nearly three-fold that of resin-modified glass ionomer, and matched/exceeded a composite with little F release. In summary, novel CaF(2) nanoparticles produced high F release at low filler levels, thereby making room in resin for reinforcement glass. This yielded nanocomposites with high F-release and stress-bearing properties, which may help reduce secondary caries and restoration fracture.
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Affiliation(s)
- H H K Xu
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201, USA.
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Xu HHK, Weir MD, Sun L, Moreau JL, Takagi S, Chow LC, Antonucci JM. Strong nanocomposites with Ca, PO(4), and F release for caries inhibition. J Dent Res 2010; 89:19-28. [PMID: 19948941 DOI: 10.1177/0022034509351969] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This article reviews recent studies on: (1) the synthesis of novel calcium phosphate and calcium fluoride nanoparticles and their incorporation into dental resins to develop nanocomposites; (2) the effects of key microstructural parameters on Ca, PO(4), and F ion release from nanocomposites, including the effects of nanofiller volume fraction, particle size, and silanization; and (3) mechanical properties of nanocomposites, including water-aging effects, flexural strength, fracture toughness, and three-body wear. This article demonstrates that a major advantage of using the new nanoparticles is that high levels of Ca, PO(4), and F release can be achieved at low filler levels in the resin, because of the high surface areas of the nanoparticles. This leaves room in the resin for substantial reinforcement fillers. The combination of releasing nanofillers with stable and strong reinforcing fillers is promising to yield a nanocomposite with both stress-bearing and caries-inhibiting capabilities, a combination not yet available in current materials.
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Affiliation(s)
- H H K Xu
- Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, 650 West Baltimore Street, Baltimore, MD 21201, USA.
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