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Xie Y, Chen R, Yao W, Ma L, Li B. Synergistic effect of ion-releasing fillers on the remineralization and mechanical properties of resin-dentin bonding interfaces. Biomed Phys Eng Express 2023; 9:062001. [PMID: 37832527 DOI: 10.1088/2057-1976/ad0300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 10/13/2023] [Indexed: 10/15/2023]
Abstract
In modern restorative dentistry, adhesive resin materials are vital for achieving minimally invasive, esthetic, and tooth-preserving restorations. However, exposed collagen fibers are found in the hybrid layer of the resin-dentin bonding interface due to incomplete resin penetration. As a result, the hybrid layer is susceptible to attack by internal and external factors such as hydrolysis and enzymatic degradation, and the durability of dentin bonding remains limited. Therefore, efforts have been made to improve the stability of the resin-dentin interface and achieve long-term clinical success. New ion-releasing adhesive resin materials are synthesized by introducing remineralizing ions such as calcium and phosphorus, which continuously release mineral ions into the bonding interface in resin-bonded restorations to achieve dentin biomimetic remineralization and improve bond durability. As an adhesive resin material capable of biomimetic mineralization, maintaining excellent bond strength and restoring the mechanical properties of demineralized dentin is the key to its function. This paper reviews whether ion-releasing dental adhesive materials can maintain the mechanical properties of the resin-dentin bonding interface by supplementing the various active ingredients required for dentin remineralization from three aspects: phosphate, silicate, and bioactive glass.
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Affiliation(s)
- Yimeng Xie
- Shanxi Medical University School and Hospital of Stomatology, Taiyuan, 030001, People's Republic of China
- Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, People's Republic of China
| | - Ruhua Chen
- Shanxi Medical University School and Hospital of Stomatology, Taiyuan, 030001, People's Republic of China
- Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, People's Republic of China
| | - Wei Yao
- Shanxi Medical University School and Hospital of Stomatology, Taiyuan, 030001, People's Republic of China
- Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, People's Republic of China
| | - Liang Ma
- Shanxi Medical University School and Hospital of Stomatology, Taiyuan, 030001, People's Republic of China
- Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, People's Republic of China
| | - Bing Li
- Shanxi Medical University School and Hospital of Stomatology, Taiyuan, 030001, People's Republic of China
- Shanxi Province Key Laboratory of Oral Diseases Prevention and New Materials, Taiyuan 030001, People's Republic of China
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Dorozhkin SV. Synthetic amorphous calcium phosphates (ACPs): preparation, structure, properties, and biomedical applications. Biomater Sci 2021; 9:7748-7798. [PMID: 34755730 DOI: 10.1039/d1bm01239h] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Amorphous calcium phosphates (ACPs) represent a metastable amorphous state of other calcium orthophosphates (abbreviated as CaPO4) possessing variable compositional but rather identical glass-like physical properties, in which there are neither translational nor orientational long-range orders of the atomic positions. In nature, ACPs of a biological origin are found in the calcified tissues of mammals, some parts of primitive organisms, as well as in the mammalian milk. Manmade ACPs can be synthesized in a laboratory by various methods including wet-chemical precipitation, in which they are the first solid phases, precipitated after a rapid mixing of aqueous solutions containing dissolved ions of Ca2+ and PO43- in sufficient amounts. Due to the amorphous nature, all types of synthetic ACPs appear to be thermodynamically unstable and, unless stored in dry conditions or doped by stabilizers, they tend to transform spontaneously to crystalline CaPO4, mainly to ones with an apatitic structure. This intrinsic metastability of the ACPs is of a great biological relevance. In particular, the initiating role that metastable ACPs play in matrix vesicle biomineralization raises their importance from a mere laboratory curiosity to that of a reasonable key intermediate in skeletal calcifications. In addition, synthetic ACPs appear to be very promising biomaterials both for manufacturing artificial bone grafts and for dental applications. In this review, the current knowledge on the occurrence, structural design, chemical composition, preparation, properties, and biomedical applications of the synthetic ACPs have been summarized.
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Eliaz N, Metoki N. Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications. MATERIALS (BASEL, SWITZERLAND) 2017; 10:E334. [PMID: 28772697 PMCID: PMC5506916 DOI: 10.3390/ma10040334] [Citation(s) in RCA: 393] [Impact Index Per Article: 56.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 03/15/2017] [Accepted: 03/22/2017] [Indexed: 02/06/2023]
Abstract
Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs.
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Affiliation(s)
- Noam Eliaz
- Biomaterials and Corrosion Lab, Department of Materials Science and Engineering, Tel-Aviv University, Ramat Aviv 6997801, Israel.
| | - Noah Metoki
- Biomaterials and Corrosion Lab, Department of Materials Science and Engineering, Tel-Aviv University, Ramat Aviv 6997801, Israel.
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Bartolozzi I, Solaro R, Chiellini E, Mari G. Polymeric Sorbents for Virucide Agents in Blood Treatments. J BIOACT COMPAT POL 2016. [DOI: 10.1177/0883911507080264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Hydrophilic polystyrene (PS) type resins displaying excellent adsorption capacity for aromatic molecules in water were obtained by chemical modification of mesoporous cross-linked PS-type resins with a variety of hydrophilic reagents. The vinyl groups available on the surface of the resin beads were utilized as reactive sites for free radical grafting of hydrophilic moieties. Qualitative and semi-quantitative assessments of the functionalization degree were performed by Fourier transformed infrared (FTIR) spectroscopic analysis. Wetting and water uptake tests confirmed the occurrence of functionalization. The removal of an acridine virucide agent using the modified PS resins was tested under physiological conditions at pH 7.4. The virucide uptake capacity of the modified resins was in some cases almost quantitative. Antipyrogen treatment at 180°C for 8 h did not significantly affect the resin hydrophilicity, although a slight decrease in the adsorption capacity was detected. These modified resins were evaluated in hemofiltration procedures as virucide sorbents during the antiviral stage.
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Affiliation(s)
- I. Bartolozzi
- Department of Chemistry and Industrial Chemistry University of Pisa, Via Risorgimento 35, 56126 Pisa, Italy
| | - R. Solaro
- Department of Chemistry and Industrial Chemistry University of Pisa, Via Risorgimento 35, 56126 Pisa, Italy
| | - E. Chiellini
- Department of Chemistry and Industrial Chemistry University of Pisa, Via Risorgimento 35, 56126 Pisa, Italy,
| | - G. Mari
- Fresenius Hemocare Italia srl, via Santi 293 41032 Cavezzo (MO), Italy
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O'Donnell JNR, Antonucci JM, Skrtic D. Amorphous calcium phosphate composites with improved mechanical properties. J BIOACT COMPAT POL 2016; 21:169-184. [PMID: 18688290 DOI: 10.1177/0883911506064476] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hybridized zirconium amorphous calcium phosphate (ACP)-filled methacrylate composites make good calcium and phosphate releasing materials for anti-demineralizing/remineralizing applications with low mechanical demands. The objective of this study was to assess the effect of the particle size of the filler on the mechanical properties of these composites. Photo-curable resins were formulated from ethoxylated bisphenol A dimethacrylate, triethylene glycol dimethacrylate, 2-hydroxyethyl methacrylate and methacryloxyethyl phthalate. Camphorquinone and ethyl-4-N,N-dimethylaminobenzoate were utilized as components of the photoinitiator system. After 2 h of mechanical milling in isopropanol, an approximate 64 % reduction in the median particle diameter was observed [27.48 μm vs. 9.98 μm] for unmilled and milled wet ACP, respectively. Dry ACP showed a 43 % reduction in particle size from pre- to post-milling. As well as dry composites, those that had been immersed in aqueous media were evaluated for their Young's Modulus, water sorption, biaxial tensile, three-point flexural and diametral tensile strength. Mechanically milling the filler increased the volume of fine particles in the composite specimens, resulting in a more homogeneous intra-composite distribution of ACP and a reduction in voids. In turn, less water diffused into the milled composites upon aqueous exposure, and they showed a marked improvement in biaxial flexure strength and a moderate improvement in flexural strength over composites with unmilled ACP. The demonstrated improvement in the mechanical stability of milled Zr-ACP composites may help in extending their dental applicability.
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Affiliation(s)
- J N R O'Donnell
- Paffenbarger Research Center, American Dental Association Foundation, Gaithersburg, MD 20899, USA
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Dorozhkin SV. Calcium orthophosphates in dentistry. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2013; 24:1335-1363. [PMID: 23468163 DOI: 10.1007/s10856-013-4898-1] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/18/2013] [Indexed: 06/01/2023]
Abstract
Dental caries, also known as tooth decay or a cavity, remains a major public health problem in the most communities even though the prevalence of disease has decreased since the introduction of fluorides for dental care. Therefore, biomaterials to fill dental defects appear to be necessary to fulfill customers' needs regarding the properties and the processing of the products. Bioceramics and glass-ceramics are widely used for these purposes, as dental inlays, onlays, veneers, crowns or bridges. Calcium orthophosphates belong to bioceramics but they have some specific advantages over other types of bioceramics due to a chemical similarity to the inorganic part of both human and mammalian bones and teeth. Therefore, calcium orthophosphates (both alone and as components of various formulations) are used in dentistry as both dental fillers and implantable scaffolds. This review provides brief information on calcium orthophosphates and describes in details current state-of-the-art on their applications in dentistry and dentistry-related fields. Among the recognized dental specialties, calcium orthophosphates are most frequently used in periodontics; however, the majority of the publications on calcium orthophosphates in dentistry are devoted to unspecified "dental" fields.
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Mehdawi IM, Pratten J, Spratt DA, Knowles JC, Young AM. High strength re-mineralizing, antibacterial dental composites with reactive calcium phosphates. Dent Mater 2013; 29:473-84. [PMID: 23434447 DOI: 10.1016/j.dental.2013.01.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 09/12/2012] [Accepted: 01/25/2013] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Development of high strength dental composites with adhesive, antibacterial and re-mineralizing potential. MATERIALS Urethane and triethylene glycol dimethacrylates were combined with HEMA (10 or 20wt%) and 2MP (2 or 10wt%), antibacterial chlorhexidine (2.5wt%) and chemical cure initiators. Reactive mono/tri calcium phosphate (CP) mixed with silica/silicon carbide nanoparticles (S) (CP:S weight ratio 1:2 or 2:1) was added (50wt%). RESULTS Decreasing CP/S ratio and HEMA content reduced monomer conversion at 15min from 93 to 63%. Conversely, decreasing CP/S increased initial "dry" compressive (137-203MPa) and flexural (79-116MPa) strength. With high HEMA content, these decreased by ∼15-20MPa upon 24h water storage. With low HEMA content, average decline was <8MPa due to reduced water sorption. Early water sorption induced mass increase, volume expansion, mono calcium phosphate dissolution and chlorhexidine release, were proportional to the initial calcium phosphate content. Furthermore, they increased ∼1.5 fold upon raising HEMA wt%. These diffusion controlled processes and strength decline slowed after 24h as phosphates reaction bound water within the materials. Increasing 2MP concentration reduced calcium release but did not affect strength. Formulations with high CP/S indicated greater antibacterial activity in agar diffusion and in vitro biofilm tests. SIGNIFICANCE New material use beneath a conventional composite could potentially reduce high failure rates associated with residual caries and bacterial microleakage.
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Affiliation(s)
- Idris M Mehdawi
- UCL Eastman Dental Institute, 256 Gray's Inn Road, London, UK
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Zhao J, Liu Y, Sun WB, Yang X. First detection, characterization, and application of amorphous calcium phosphate in dentistry. J Dent Sci 2012. [DOI: 10.1016/j.jds.2012.09.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Miao X, Li Y, Zhang Q, Zhu M, Wang H. Low shrinkage light curable dental nanocomposites using SiO2 microspheres as fillers. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012; 32:2115-2121. [DOI: 10.1016/j.msec.2012.05.053] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 05/27/2012] [Accepted: 05/31/2012] [Indexed: 10/28/2022]
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Zhao J, Liu Y, Sun WB, Zhang H. Amorphous calcium phosphate and its application in dentistry. Chem Cent J 2011; 5:40. [PMID: 21740535 PMCID: PMC3143077 DOI: 10.1186/1752-153x-5-40] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 07/08/2011] [Indexed: 11/10/2022] Open
Abstract
Amorphous Calcium Phosphate (ACP) is an essential mineral phase formed in mineralized tissues and the first commercial product as artificial hydroxyapatite. ACP is unique among all forms of calcium phosphates in that it lacks long-range, periodic atomic scale order of crystalline calcium phosphates. The X-ray diffraction pattern is broad and diffuse with a maximum at 25 degree 2 theta, and no other different features compared with well-crystallized hydroxyapatite. Under electron microscopy, its morphological form is shown as small spheroidal particles in the scale of tenths nanometer. In aqueous media, ACP is easily transformed into crystalline phases such as octacalcium phosphate and apatite due to the growing of microcrystalline. It has been demonstrated that ACP has better osteoconductivity and biodegradability than tricalcium phosphate and hydroxyapatite in vivo. Moreover, it can increase alkaline phosphatase activities of mesoblasts, enhance cell proliferation and promote cell adhesion. The unique role of ACP during the formation of mineralized tissues makes it a promising candidate material for tissue repair and regeneration. ACP may also be a potential remineralizing agent in dental applications. Recently developed ACP-filled bioactive composites are believed to be effective anti-demineralizing/remineralizing agents for the preservation and repair of tooth structures. This review provides an overview of the development, structure, chemical composition, morphological characterization, phase transformation and biomedical application of ACP in dentistry.
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Affiliation(s)
- Jie Zhao
- Stomatological Hospital, Nanjing University Medical School, 30 Zhongyang Road, Nanjing 210008, China.
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Fine-Tuning of Polymeric Resins and Their Interfaces with Amorphous Calcium Phosphate. A Strategy for Designing Effective Remineralizing Dental Composites. Polymers (Basel) 2010; 2:378-392. [PMID: 21283507 DOI: 10.3390/polym2040378] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
For over a decade our group has been designing, preparing and evaluating bioactive, remineralizing composites based on amorphous calcium phosphate (ACP) fillers embedded in polymerized methacrylate resin matrices. In these studies a major focus has been on exploring structure-property relationships of the matrix phase of these composites on their anti-cariogenic potential. The main challenges were to gain a better understanding of polymer matrix/filler interfacial properties through controlling the surface properties of the fillers or through fine-tuning of the resin matrix. In this work, we describe the effect of chemical structure and composition of the resin matrices on some of the critical physicochemical properties of the copolymers and their ACP composites. Such structure-property studies are essential in formulating clinically effective products, and this knowledge base is likely to have strong impact on the future design of therapeutic materials, appropriate for mineral restoration in defective tooth structures.
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Uysal T, Amasyali M, Ozcan S, Koyuturk AE, Akyol M, Sagdic D. In vivo effects of amorphous calcium phosphate-containing orthodontic composite on enamel demineralization around orthodontic brackets. Aust Dent J 2010; 55:285-91. [DOI: 10.1111/j.1834-7819.2010.01236.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Johns JI, O’Donnell JNR, Skrtic D. Selected physicochemical properties of the experimental endodontic sealer. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2010; 21:797-805. [PMID: 19768397 PMCID: PMC2836201 DOI: 10.1007/s10856-009-3873-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Accepted: 09/09/2009] [Indexed: 05/28/2023]
Abstract
This study explores water sorption, hygroscopic expansion, mechanical strength and ion release from the experimental amorphous calcium phosphate (ACP) composites formulated for application as endodontic sealers. Light-cure (LC) and dual-cure (DC; combined light and chemical cure) resins comprised urethane dimethacrylate (UDMA), 2-hydroxyethyl methacrylate (HEMA), methacryloyloxyethyl phthalate (MEP) and a high molecular mass oligomeric co-monomer, poly(ethyleneglycol)-extended UDMA (PEG-U) (designated UPHM resin). To fabricate composites, a mass fraction of 60% UPHM resin was blended with a mass fraction of 40% as-made (am-) or ground (g-) ACP. Glass-filled composites were used as controls. Both DC and LC ACP UPHM composites exhibited relatively high levels of water sorption accompanied by a significant hygroscopic expansion. The latter may potentially be useful to offset high polymerization stresses that develop in these materials. Ion release profiles of the experimental materials confirmed their potential for regeneration of mineral-deficient tooth structures. Their moderate to low mechanical strength after 3 months of aqueous immersion did not diminish the enthusiasm for the proposed use as endodontic sealers. For that application, DC g-ACP composites appear to be the most adequate, but micro-leakage and quantitative leachability studies are needed to fully establish their suitability.
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Affiliation(s)
- J. I. Johns
- Paffenbarger Research Center, American Dental Association Foundation, National Institute of Standards and Technology, 100 Bureau Drive Stop 8546, Gaithersburg, MD 20899-8546, USA
| | - J. N. R. O’Donnell
- Paffenbarger Research Center, American Dental Association Foundation, National Institute of Standards and Technology, 100 Bureau Drive Stop 8546, Gaithersburg, MD 20899-8546, USA
| | - D. Skrtic
- Paffenbarger Research Center, American Dental Association Foundation, National Institute of Standards and Technology, 100 Bureau Drive Stop 8546, Gaithersburg, MD 20899-8546, USA
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Uysal T, Ustdal A, Nur M, Catalbas B. Bond strength of ceramic brackets bonded to enamel with amorphous calcium phosphate-containing orthodontic composite. Eur J Orthod 2010; 32:281-4. [DOI: 10.1093/ejo/cjp115] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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O'Donnell JNR, Skrtic D. Degree of vinyl conversion, polymerization shrinkage and stress development in experimental endodontic composite. JOURNAL OF BIOMIMETICS, BIOMATERIALS, AND TISSUE ENGINEERING 2009; 4:1-12. [PMID: 20411033 PMCID: PMC2856955 DOI: 10.4028/www.scientific.net/jbbte.4.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study explores degree of vinyl conversion (DVC), polymerization shrinkage (PS) and shrinkage stress (PSS) of the experimental amorphous calcium phosphate (ACP) composites intended for use as an endodontic sealer. Light-cure (LC), chemical cure (CC) or dual-cure (DC; combined light and chemical cure) resins comprised urethane dimethacrylate (UDMA), 2-hydroxyethyl methacrylate (HEMA), methacryloyloxyethyl phthalate (MEP) and a high molecular mass oligomeric co-monomer, poly(ethyleneglycol)-extended UDMA (PEG-U) (designated UPHM resin). To fabricate composites, a mass fraction of 60 % UPHM resin was blended with a mass fraction of 40 % as-made (am-ACP) or ground ACP (g-ACP). DVC values of copolymer (unfilled UPHM resin) and composite specimens were determined by infrared spectroscopy. Glass-filled composites were used as controls. PS and PSS of composites were determined by dilatometry and tensometry, respectively. LC copolymers attained extraordinary high DVC values at 24 h post-cure (95.7 %), compared to CC (52 %) and DC (79.3 %) copolymer specimens. While the DVC values of LC and DC am-ACP composites were reduced between 5 and 10 %, DVC values of DC g-ACP composites increased almost 8 % compared to the corresponding copolymers. High DVC attained in LC composites was, expectedly, accompanied with high PS values (on average 7 vol%). However, PSS developed in LC and especially DC composites did not exceed PSS values seen in other UDMA-based composites. Based on this initial evaluation, it is concluded that, DC, g-ACP filled UPHM composite shows promise as an endodontic sealer. However, further physicochemical evaluations, including water sorption, mechanical stability and ion release as well as a leachability studies need to be performed before this experimental material is tested for cellular responses and, eventually recommended for clinical utility.
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Affiliation(s)
- J N R O'Donnell
- Paffenbarger Research Center, American Dental association Foundation, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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Structure-Composition-Property Relationships in Polymeric Amorphous Calcium Phosphate-Based Dental Composites. MATERIALS 2009; 2:1929-1959. [PMID: 21966588 PMCID: PMC3182464 DOI: 10.3390/ma2041929] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Our studies of amorphous calcium phosphate (ACP)-based materials over the last decade have yielded bioactive polymeric composites capable of protecting teeth from demineralization or even regenerating lost tooth mineral. The anti-cariogenic/re-mineralizing potential of these ACP composites originates from their propensity, when exposed to the oral environment, to release in a sustained manner sufficient levels of mineral-forming calcium and phosphate ions to promote formation of stable apatitic tooth mineral. However, the less than optimal ACP filler/resin matrix cohesion, excessive polymerization shrinkage and water sorption of these experimental materials can adversely affect their physicochemical and mechanical properties, and, ultimately, limit their lifespan. This study demonstrates the effects of chemical structure and composition of the methacrylate monomers used to form the matrix phase of composites on degree of vinyl conversion (DVC) and water sorption of both copolymers and composites and the release of mineral ions from the composites. Modification of ACP surface via introducing cations and/or polymers ab initio during filler synthesis failed to yield mechanically improved composites. However, moderate improvement in composite’s mechanical stability without compromising its remineralization potential was achieved by silanization and/or milling of ACP filler. Using ethoxylated bisphenol A dimethacrylate or urethane dimethacrylate as base monomers and adding moderate amounts of hydrophilic 2-hydroxyethyl methacrylate or its isomer ethyl-α-hydroxymethacrylate appears to be a promising route to maximize the remineralizing ability of the filler while maintaining high DVC. Exploration of the structure/composition/property relationships of ACP fillers and polymer matrices is complex but essential for achieving a better understanding of the fundamental mechanisms that govern dissolution/re-precipitation of bioactive ACP fillers, and, ultimately, the suitability of the composites for clinical evaluation.
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Uysal T, Ulker M, Baysal A, Usumez S. Microleakage between composite-wire and composite-enamel interfaces of flexible spiral wire retainers. Part 2: comparison of amorphous calcium phosphate-containing adhesive with conventional lingual retainer composite. Eur J Orthod 2009; 31:652-7. [DOI: 10.1093/ejo/cjp039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Mehdawi I, Neel EAA, Valappil SP, Palmer G, Salih V, Pratten J, Spratt DA, Young AM. Development of remineralizing, antibacterial dental materials. Acta Biomater 2009; 5:2525-39. [PMID: 19410530 DOI: 10.1016/j.actbio.2009.03.030] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 03/17/2009] [Accepted: 03/24/2009] [Indexed: 11/28/2022]
Abstract
Light curable methacrylate dental monomers containing reactive calcium phosphate filler (monocalcium phosphate monohydrate (MCPM) with particle diameter of 29 or 90microm) and beta-tricalcium phosphate (beta-TCP) at 1:1 weight ratio in a powder:liquid ratio (PLR) of 1:1 or 3:1 and chlorhexidine diacetate (0 or 5 wt.%), were investigated. Upon light exposure, approximately 90% monomer conversion was gained irrespective of the formulation. Increasing the PLR promoted water sorption by the set material, induced expansion and enhanced calcium, phosphate and chlorhexidine release. Concomitantly, a decline in compressive and biaxial flexural strengths occurred. With a reduction in MCPM particle diameter, however, calcium and phosphate release was reduced and less deterioration in strength observed. After 24h, the remaining MCPM had reacted with water and beta-TCP, forming, within the set materials, brushite of lower solubility. This provided a novel means to control water sorption, component release and strength properties. Measurable chlorhexidine release was observed for 6weeks. Both diffusion rate and total percentage of chlorhexidine release decreased with lowering PLR or by adding buffer to the storage solutions. Higher chlorhexidine release was associated with reduced bacterial growth on agar plates and in a biofilm fermenter. In cell growth media, brushite and hydroxyapatite crystals precipitated on the composite material surfaces. Cells spread on both these crystals and the exposed polymer composite surfaces, indicating their cell compatibility. These formulations could be suitable antibacterial, biocompatible and remineralizing dental adhesives/liners.
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Affiliation(s)
- Idris Mehdawi
- UCL Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD, UK
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Uysal T, Ulker M, Akdogan G, Ramoglu SI, Yilmaz E. Bond Strength of Amorphous Calcium Phosphate–Containing Orthodontic Composite Used as a Lingual Retainer Adhesive. Angle Orthod 2009; 79:117-21. [DOI: 10.2319/112807-560.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Accepted: 01/01/2008] [Indexed: 11/23/2022] Open
Abstract
Abstract
Objective: To evaluate the shear bond strength and fracture mode difference between amorphous calcium phosphate (ACP)–containing adhesive and conventional resin-based composite material used as an orthodontic lingual retainer adhesive.
Materials and Methods: Forty crowns of extracted lower human incisors were mounted in acrylic resin, leaving the buccal surface of the crowns parallel to the base of the molds. The teeth were randomly divided into two groups: experimental and control, containing 20 teeth each. Conventional lingual retainer composite (Transbond-LR, 3M-Unitek) and ACP-containing orthodontic adhesive (Aegis-Ortho) were applied to the teeth surface by packing the material into the cylindrical plastic matrices with a 2.34-mm internal diameter and a 3-mm height (Ultradent) to simulate the lingual retainer bonding. For shear bond testing, the specimens were mounted in a universal testing machine, and an apparatus (Ultradent) attached to a compression load cell was applied to each specimen until failure occurred. The shear bond data were analyzed using Student's t-test. Fracture modes were analyzed by χ2 test.
Results: The statistical test showed that the bond strengths of group 1 (control Transbond-LR, mean: 24.77 ± 9.25 MPa) and group 2 (ACP-containing adhesive, mean: 8.49 ± 2.53 MPa) were significantly different from each other. In general, a greater percentage of the fractures were adhesive at the tooth-composite interface (60% in group 1 and 55% in group 2), and no statistically significant difference was found between groups.
Conclusion: The ACP-containing Aegis-Ortho adhesive resulted in a significant decrease in bond strength to the etched enamel surface.
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Affiliation(s)
- Tancan Uysal
- a Associate Professor and Department Chair, Department of Orthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey
| | - Mustafa Ulker
- b Assistant Professor, Department of Conservative Dentistry, Faculty of Dentistry, Erciyes University Kayseri, Turkey
| | - Gulsen Akdogan
- c Instructor, Department of Mechanics, Erciyes University, Kayseri Vocational College, Kayseri, Turkey
| | - Sabri Ilhan Ramoglu
- d Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Erciyes University Kayseri, Turkey
| | - Esra Yilmaz
- e Research Assistant, Department of Orthodontics, Erciyes University Kayseri, Turkey
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Antonucci JM, O'Donnell JNR, Schumacher GE, Skrtic D. AMORPHOUS CALCIUM PHOSPHATE COMPOSITES AND THEIR EFFECT ON COMPOSITE-ADHESIVE-DENTIN BONDING. JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY 2009; 23:1133-1147. [PMID: 19696914 PMCID: PMC2729202 DOI: 10.1163/156856109x432767] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This study evaluates the bond strength and related properties of photo-polymerizable, remineralizing amorphous calcium phosphate (ACP) polymeric composite-adhesive systems to dentin after various periods of aqueous aging at 37 °C. An experimental ACP base and lining composite was made from a photo-activated resin comprising 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA) and zirconyl dimethacrylate (ZrDMA); designated BTHZ. An experimental orthodontic composite was formulated from a photo-activated resin comprising ethoxylated bisphenol A dimethacrylate (EBPADMA), TEGDMA, HEMA and methacryloxyethyl phthalate (MEP); designated ETHM. In both composite series three fillers were compared: 1) freshly precipitated zirconium-modified ACP freshly precipitated (as-prepared Zr-ACP), 2) milled Zr-ACP and 3) an ion-leachable fluoride glass. In addition to the shear bond strength (SBS), work to fracture and failure modes of the orthodontic composites were determined. The SBS of the base and lining ACP composites appeared unaffected by filler type or immersion time. In the orthodontic ACP composite series, milled ACP composites showed initial mechanical advantages over as-prepared ACP composites, and produced higher incidence of a failure mode consistent with stronger adhesion. After six months of aqueous exposure, 80 % of specimens failed at the dentin-primer interface, with a 42 % overall reduction in bond strength. BTHZ and ETHM based ACP composites are potentially effective anti-demineralizing-remineralizing agents with possible clinical utility as protective base-liners and orthodontic cements, respectively. The analysis of the bond strength and failure modalities suggests that milled ACP composites may offer greater potential in clinical applications.
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Affiliation(s)
- J M Antonucci
- Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
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21
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Antonucci JM, Fowler BO, Weir MD, Skrtic D, Stansbury JW. Effect of ethyl-alpha-hydroxymethylacrylate on selected properties of copolymers and ACP resin composites. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:3263-71. [PMID: 18470701 PMCID: PMC2561301 DOI: 10.1007/s10856-008-3463-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 04/23/2008] [Indexed: 05/26/2023]
Abstract
There is an increased interest in the development of bioactive polymeric dental composites and related materials that have potential for mineralized tissue regeneration and preservation. This study explores how the substitution of ethyl alpha-hydroxymethylacryate (EHMA) for 2-hydroxyethyl methacrylate (HEMA) in photo-activated 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA) and Bis-GMA/tri(ethylene glycol) dimethacrylate (TEGDMA) resins affected selected physicochemical properties of the polymers and their amorphous calcium phosphate (ACP) composites. Rate of polymerization and the degree of conversion (DC) of polymers {EHMA (E), HEMA (H), Bis-GMA/EHMA (BE), Bis-GMA/HEMA (BH), Bis-GMA/TEGDMA/EHMA (BTE) and Bis-GMA/TEGDMA/HEMA (BTH)} were assessed by photo-differential scanning calorimetry and Fourier-Transform Infrared (FTIR) spectroscopy. ACP/BTE and ACP/BTH composites were evaluated for DC, biaxial flexure strength (BFS), water sorption (WS) and mineral ion release. Mid-FTIR and near-IR measurements revealed the following order of decreasing DC: [E, H polymers (97.0%)] > [BE copolymer (89.9%)] > [BH copolymer (86.2%)] > [BTE, BTH copolymers (85.5%)] > [ACP/BTH composite (82.6%)] > [ACP/BTE composite (79.3%)]. Compared to HEMA, EHMA did not adversely affect the BFS of its copolymers and/or ACP composites. Lower WS of BTE copolymers and composites (28% and 14%, respectively, compared to the BTH copolymers and composites) only marginal reduced the ion release from ACP/BTE composites compared to ACP/BTH composites. More hydrophobic ACP composites with acceptable ion-releasing properties were developed by substituting the less hydrophilic EHMA for HEMA.
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Affiliation(s)
- Joseph M. Antonucci
- Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD
| | - Bruce O. Fowler
- Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD
| | - Michael D. Weir
- Paffenbarger Research Center, American Dental Association Foundation, MD
| | - Drago Skrtic
- Paffenbarger Research Center, American Dental Association Foundation, MD
| | - Jeffrey W. Stansbury
- Deparment of Chemical and Biological Engineering, University of Colorado, Boulder, CO
- Deparment of Craniofacial Biology, University of Colorado School of Dental Medicine, Aurora, CO
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22
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O'Donnell JNR, Langhorst SE, Fow MD, Antonucci JM, Skrtic D. Light-cured dimethacrylate-based resins and their composites: comparative study of mechanical strength, water sorption and ion release. J BIOACT COMPAT POL 2008; 23:207-226. [PMID: 18607513 DOI: 10.1177/0883911508089932] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study explored how resin type affects selected physicochemical properties of complex methacrylate copolymers and their amorphous calcium phosphate (ACP)-filled and glass-filled composites. Two series of photo-polymerizable resin matrices were formulated employing 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA) or an ethoxylated bisphenol A dimethacrylate (EBPADMA) as the base monomer, Unfilled copolymers and composites filled with a mass fraction with 40 %, 35 % and 30 %, respectively, of ACP or the un-silanized glass were assessed for biaxial flexure strength (BFS), water sorption (WS) and mineral ion release upon immersion in HEPES-buffered saline solution for up to six months. Substituting EBPADMA for Bis-GMA significantly reduced the WS while only marginally affected the BFS of both dry and wet copolymers. Independent of the filler level, both dry and wet ACP composites formulated with either BTHM or ETHM resins were mechanically weaker than the corresponding copolymers. The BFS of ACP composite specimens after 1 month in saline did not further decrease with further aqueous exposure. The BFS of glass-filled composites decreased with the increased level of the glass filler and the time of aqueous exposure. After 6 months of immersion, the BFS of glass-filled BTHM and ETHM composites, respectively, remained 58 % and 41 % higher than the BFS of the corresponding ACP composites. Ion release data indicated that a minimum mass fraction of 35 % ACP was required to attain the desired solution supersaturation with respect to hydroxyapatite for both the BTHM and ETHM derived composites.
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Affiliation(s)
- J N R O'Donnell
- Paffenbarger Research Center, American Dental Association Foundation, Gaithersburg, MD, USA
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23
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Regnault WF, Icenogle TB, Antonucci JM, Skrtic D. Amorphous calcium phosphate/urethane methacrylate resin composites. I. Physicochemical characterization. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:507-15. [PMID: 17619969 PMCID: PMC2391310 DOI: 10.1007/s10856-007-3178-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Accepted: 05/17/2007] [Indexed: 05/16/2023]
Abstract
Urethane dimethacrylate (UDMA), an oligomeric poly(ethylene glycol) extended UDMA (PEG-U) and a blend of UDMA/PEG-U were chosen as model systems for introducing both hydrophobic and hydrophilic segments and a range of compliances in their derived polymers. Experimental composites based on these three resins with amorphous calcium phosphate (ACP) as the filler phase were polymerized and evaluated for mechanical strength and ion release profiles in different aqueous media. Strength of all composites decreased upon immersion in saline (pH = 7.4). Both polymer matrix composition and the pH of the liquid environment strongly affected the ion release kinetics. In saline, the UDMA/PEG-U composite showed a sustained release for at least 350 h. The initially high ion release of the PEG-U composites decreased after 72 h, seemingly due to the mineral re-deposition at the composite surface. Internal conversion from ACP to poorly crystallized apatite could be observed by X-ray diffraction. In various lactic acid (LA) environments (initial pH = 5.1) ion release kinetics was much more complex. In LA medium without thymol and/or carboxymethylcellulose, as a result of unfavorable changes in the internal calcium/phosphate ion stoichiometry, the ion release rate greatly increased but without observable conversion of ACP to apatite.
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Affiliation(s)
- William F Regnault
- Center for Devices and Radiological Health, Food and Drug Administration, Rockville, MD, USA
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24
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Schumacher GE, Antonucci JM, O'Donnell JNR, Skrtic D. The use of amorphous calcium phosphate composites as bioactive basing materials: their effect on the strength of the composite/adhesive/dentin bond. J Am Dent Assoc 2007; 138:1476-84. [PMID: 17974645 PMCID: PMC2562752 DOI: 10.14219/jada.archive.2007.0084] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Amorphous calcium phosphate (ACP) composites release calcium and phosphate ions in aqueous environments, which may lead to deposition of apatitic mineral in tooth structure. The authors evaluate the strength of the composite/adhesive/dentin bond shear bond strength (SBS) for ACP basing-composites after various periods of water aging. METHODS The authors made the experimental composites by using two resin matrices with various ACPs or a commercial strontium ion-leachable glass. They applied successive coats of a dentin adhesive and basing composite to an acid-etched dentin surface and photopolymerized them. They added a commercial resin-based composite and light cured it. They determined the specimens' SBS after they were aged in water for various periods at 37 degrees C. RESULTS The SBS of the ACP composites was 18.3 +/- 3.5 megapascals, independent of filler type, resin composition and water-aging interval. After 24 hours of water aging, 92.6 percent of surfaces showed the adhesive failure. After two weeks of water aging, adhesive/cohesive failures were predominant in unmilled and milled ACP composites. CONCLUSIONS The SBS of ACP composites appears to be unaffected by filler type or immersion time for up to six months. The type of adhesive failure occurring with prolonged aqueous exposure is affected by filler type. CLINICAL IMPLICATIONS These materials may be effective remineralizing/antidemineralizing agents and may be clinically applicable as adhesives, protective liners and bases, orthodontic cements and pit-and-fissure sealants.
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Affiliation(s)
- Gary E Schumacher
- Paffenbarger Research Center, American Dental Association Foundation, 100 Bureau Drive, Gaithersburg, MD 20899, USA
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25
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Antonucci JM, Liu DW, Skrtic D. Amorphous Calcium Phosphate Based Composites: Effect of Surfactants and Poly(ethylene oxide) on Filler and Composite Properties. J DISPER SCI TECHNOL 2007; 28:819-824. [PMID: 18714365 DOI: 10.1080/01932690701346255] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The uncontrolled aggregation of amorphous calcium phosphate (ACP) particulate fillers and their uneven distribution within polymer matrices can have adverse effects on the properties of ACP composites. In this paper we assessed the influence of non-ionic and anionic surfactants and poly(ethylene oxide) (PEO) introduced during the preparation of ACP on the particle size distribution and compositional properties of ACP. In addition, the mechanical strength of polymeric composites utilizing such fillers with a photo-activated binary methacrylate resin was evaluated. Zirconia-hybridized ACP (Zr-ACP) filler and its corresponding composite served as controls for this study. Surfactant- and PEO-ACPs had an average water content of 16.8 % by mass. Introduction of the anionic surfactant reduced the median particle diameter about 45 % (4.1 μm vs. 7.4 μm for the Zr-ACP control). In the presence of PEO, however, the d(m) increased to 14.1 μm. There was no improvement in the biaxial flexure strength (BFS) in any of the dry composite specimens prepared with the surfactant- and/or PEO-ACPs compared to those formulated with Zr-ACP. The BFS of wet composite specimens decreased by 50 % or more after a month-long exposure to saline solutions. Other types of surfactants and/or polymers as well as alternative surface modification protocols need to be explored for their potential to provide better dispersion of ACP into the matrix resin and better mechanical performance ACP composites.
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Affiliation(s)
- J M Antonucci
- Polymers Division, National Institute of Standards and Technology, Gaithersburg, MD, USA
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26
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Skrtic D, Antonucci JM. Effect of Chemical Structure and Composition of the Resin Phase on Vinyl Conversion of Amorphous Calcium Phosphate-filled Composites. POLYM INT 2007; 56:497-505. [PMID: 18714369 PMCID: PMC2517860 DOI: 10.1002/pi.2129] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Accepted: 07/25/2006] [Indexed: 11/06/2022]
Abstract
The objective of this study was to elucidate the effect of chemical structure and composition of the polymer matrix on the degree of vinyl conversion (DC) of copolymers (unfilled resins) and their amorphous calcium phosphate (ACP) composites attained upon photo-polymerization. The DC can also be an indicator of the relative potential of these polymeric materials to leach out into the oral environment un-reacted monomers that could adversely affect their biocompatibility. The following resins were examined: 1) 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (1:1 mass ratio; BT resin) combined with hydroxyethyl methacrylate (HEMA; BTH resin) and with HEMA and zirconyl dimethacrylate (BTHZ resin), 2) urethane dimethacrylate (UDMA)/HEMA resins, and 3) pyromellitic glycerol dimethacrylate (PMGDMA)/TEGDMA (PT resin). To make composite specimens, resins were mixed with a mass fraction of 40 % zirconia-hybridized ACP. Copolymers and their composites were evaluated by near infra-red spectroscopy for DC after 1 d and 28 d post-cure at 23 °C. Inclusion of HEMA into the BT and UDMA resins yielded copolymers and composites with the highest DCs. The significantly lower DCs of PT copolymers and their composites are attributed to the rigid aromatic core structure, tetra-vinyl functionality and limited methacrylate side-chain flexibility of the surface-active PMGDMA monomer. There was, however, an increase in the 28 d DC for the PT materials as there was for the BTHZ system. Surprisingly, the usual decrease observed in DC in going from unfilled polymer to composite was reversed for the PT system.
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Affiliation(s)
- D Skrtic
- Paffenbarger Research Center, American Dental Association Foundation, Gaithersburg, MD 20899, USA
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27
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Whited BM, Skrtic D, Love BJ, Goldstein AS. Osteoblast response to zirconia-hybridized pyrophosphate-stabilized amorphous calcium phosphate. J Biomed Mater Res A 2006; 76:596-604. [PMID: 16278876 PMCID: PMC1477539 DOI: 10.1002/jbm.a.30573] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Calcium phosphate bioceramics, such as hydroxyapatite, have long been used as bone substitutes because of their proven biocompatibility and bone binding properties in vivo. Recently, a zirconia-hybridized pyrophosphate-stabilized amorphous calcium phosphate (Zr-ACP) has been synthesized, which is more soluble than hydroxyapatite and allows for controlled release of calcium and phosphate ions. These ions have been postulated to increase osteoblast differentiation and mineralization in vitro. The focus of this work is to elucidate the physicochemical properties of Zr-ACP and to measure cell response to Zr-ACP in vitro using a MC3T3-E1 mouse calvarial-derived osteoprogenitor cell line. Cells were cultured in osteogenic medium and mineral was added to culture at different stages in cell maturation. Culture in the presence of Zr-ACP showed significant increases in cell proliferation, alkaline phosphatase activity (ALP), and osteopontin (OPN) synthesis, whereas collagen synthesis was unaffected. In addition, calcium and phosphate ion concentrations and medium pH were found to transiently increase with the addition of Zr-ACP, and are hypothesized to be responsible for the osteogenic effect of Zr-ACP.
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Affiliation(s)
- Bryce M Whited
- School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0298, USA
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28
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Skrtic D, Antonucci JM. Dental composites based on amorphous calcium phosphate - resin composition/physicochemical properties study. J Biomater Appl 2006; 21:375-93. [PMID: 16684798 PMCID: PMC2424213 DOI: 10.1177/0885328206064823] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study explores how the resin composition/structure affects the physicochemical properties of copolymers and their amorphous calcium phosphate (ACP)-filled composites. A series of photo-polymerizable binary and ternary matrices are formulated utilizing 2,2-bis[ p-(2(')-hydroxy-3(')methacryloxypropoxy)phenyl]propane, 2,2-bis[ p-(2(')-methacryloxypropoxy)phenyl]-propane (EBPADMA), or a urethane dimethacrylate as base monomers, and triethylene glycol dimethacrylate or hexamethylene dimethacrylate (HmDMA) with or without 2-hydroxyethyl methacrylate (HEMA) as diluent monomer. Unfilled copolymers and composites filled with 40% by mass zirconia-hybridized ACP are evaluated for biaxial flexure strength (BFS), degree of conversion (DC), mineral ion release, polymerization shrinkage (PS), and water sorption (WS). The average DC values are 82-94% and 74-91% for copolymers and composites, respectively. Unrelated to the resin composition, the PS values of composites are up to 8.4 vol. % and the BFS values of wet composite specimens are on average 51 +/- 8 MPa. The maximum WS values attained in copolymers and composites reach 4.8 mass%. Inclusion of hydrophobic HmDMA monomer in the matrices significantly reduces the WS. The levels of Ca and PO(4) released from all types of composites are significantly above the minimum necessary for the re-deposition of apatite to occur. Elevated Ca, and to a lesser extent PO(4) release, is observed in HEMA-containing, ternary EBPADMA formulations. Further resin reformulations may be needed to improve the PS of composite specimens. Poor dispersion of ;as-synthesized' ACP within the composite contributes to their inferior mechanical performance.
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Affiliation(s)
- D Skrtic
- Paffenbarger Research Center, American Dental Association Foundation, National Institute of Standards and Technology Gaithersburg, MD 20899, USA. drago.skrtic@nist. gov
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29
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Skrtic D, Antonucci JM, Liu DW. Ethoxylated bisphenol dimethacrylate-based amorphous calcium phosphate composites. Acta Biomater 2006; 2:85-94. [PMID: 16701862 PMCID: PMC1839056 DOI: 10.1016/j.actbio.2005.10.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 10/07/2005] [Accepted: 10/19/2005] [Indexed: 11/20/2022]
Abstract
Improving the anti-demineralizing/remineralizing and mechanical properties of amorphous calcium phosphate (ACP) composites has been the focus of our recent research. In this study, an ethoxylated bisphenol A dimethacrylate (EBPADMA) was blended with triethylene glycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA) and methacryloxyethyl phthalate (MEP) to form experimental resins with different EBPADMA/TEGDMA molar ratios (0.50, 0.85 and 1.35) and a constant HEMA/MEP molar ratio (8.26). Composites were prepared by admixture of either unmilled or milled zirconia-ACP filler (40% by mass) and photo-activated resin (60% by mass). One aim was to test if improved ion release can be achieved by elevating the EBPADMA/TEGDMA ratio while lowering the level of surface active methacryloxyethyl phthalate in the resin without adversely affecting the biaxial flexure strength (BFS), degree of vinyl conversion (DC) and water sorption (WS) of composites. A second aim was to assess the effect of using milled vs. unmilled ACP on these properties. Ion release of all composites was significantly above the theoretical minimum necessary for remineralization. Calcium ion release was not impeded by binding with the carboxylic acid groups of MEP. Increased supersaturation was attained with increasing EBPADMA/TEGDMA ratio in the resin. Variations in resin composition had no effect on BFS or DC of composites. The BFS of the milled ACP composites was higher than the BFS of unmilled ACP composites (56% and 79%, respectively for dry and wet specimens). DC of composites was only moderately reduced (13.6% and 7.3%, for unmilled and milled ACP, respectively) compared to unfilled resins. WS decreased in the following order: unmilled ACP composites>milled ACP composites>copolymers. Fine-tuning of the resin and utilizing milled ACP filler improved the remineralizing potential of ACP composites without impeding their DC, BFS or WS.
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Affiliation(s)
- Drago Skrtic
- National Institute of Standards and Technology, Paffenbarger Research Center, Gaithersburg, MD, USA.
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