Abstract:
:This study aims at modifying dual-cure composite cements by adding thio-urethane oligomers to improve mechanical properties, especially fracture toughness, and reduce polymerization stress. Thiol-functionalized oligomers were synthesized by combining 1,3-bis(1-isocyanato-1-methylethyl)benzene with trimethylol-tris-3-mercaptopropionate, at 1:2 isocyanate:thiol. Oligomer was added at 0, 10 or 20 wt% to BisGMA-UDMA-TEGDMA (5:3:2, with 25 wt% silanated inorganic fillers) or to one commercial composite cement (Relyx Ultimate, 3M Espe). Near-IR was used to measure methacrylate conversion after photoactivation (700 mW/cm(2) × 60s) and after 72 h. Flexural strength and modulus, toughness, and fracture toughness were evaluated in three-point bending. Polymerization stress was measured with the Bioman. The microtensile bond strength of an indirect composite and a glass ceramic to dentin was also evaluated. Results were analyzed with analysis of variance and Tukey's test (α = 0.05). For BisGMA-UDMA-TEGDMA cements, conversion values were not affected by the addition of thio-urethanes. Flexural strength/modulus increased significantly for both oligomer concentrations, with a 3-fold increase in toughness at 20 wt%. Fracture toughness increased over 2-fold for the thio-urethane modified groups. Contraction stress was reduced by 40% to 50% with the addition of thio-urethanes. The addition of thio-urethane to the commercial cement led to similar flexural strength, toughness, and conversion at 72h compared to the control. Flexural modulus decreased for the 20 wt% group, due to the dilution of the overall filler volume, which also led to decreased stress. However, fracture toughness increased by up to 50%. The microtensile bond strength increased for the experimental composite cement with 20 wt% thio-urethane bonding for both an indirect composite and a glass ceramic. Novel dual-cured composite cements containing thio-urethanes showed increased toughness, fracture toughness and bond strength to dentin while demonstrating reduced contraction stress. All of these benefits are derived without compromising the methacrylate conversion of the resin component. The modification does not require changing the operatory technique.
journal_name
J Dent Resjournal_title
Journal of dental researchauthors
Bacchi A,Dobson A,Ferracane JL,Consani R,Pfeifer CSdoi
10.1177/0022034514551768subject
Has Abstractpub_date
2014-12-01 00:00:00pages
1320-5issue
12eissn
0022-0345issn
1544-0591pii
0022034514551768journal_volume
93pub_type
杂志文章abstract::Evaluation of long-term mechanical behavior of new types of restorations in clinical trials is time-consuming. A partial alternative can be found in experimental fatigue-testing, which simulates accelerated mechanical deterioration. The aim of this study was to determine the feasibility of using fatigue-testing of a c...
journal_title:Journal of dental research
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1177/00220345920710050301
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abstract::Previous studies have shown that therapeutic pulsed ultrasound (pulsed) has superior stimulatory effect on bone fracture healing compared with continuous ultrasound (continuous). Our predictive hypothesis was that pulsed ultrasound can produce better bone formation during mandibular osteodistraction than continuous ul...
journal_title:Journal of dental research
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journal_title:Journal of dental research
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abstract::In the absence of active pulmonary disease, mycobacterial infection frequently causes arthritis and can be considered to initiate autoimmune diseases such as rheumatoid arthritis. Temporomandibular disorder (TMD) is a disease in which pain and impaired mandibular movement appear to arise directly from degenerative or ...
journal_title:Journal of dental research
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doi:10.1177/00220345000790100401
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abstract::In this study, the differences in lesion remineralization and fluoride uptake after brushing with a 300 ppm F or a 1000 ppm F dentifrice (as NaF) were investigated. Twenty volunteers with partial dentures in their lower jaws were divided into two groups. Bovine enamel slabs with artificial lesions were mounted in the ...
journal_title:Journal of dental research
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journal_title:Journal of dental research
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更新日期:2011-12-01 00:00:00
abstract::Although a large body of scientific literature shows that background color and luminance affect color perception, previous measurements of tooth color difference thresholds have not taken the effects of viewing context into account. The present study tested the hypothesis that differences in skin/gingival color influe...
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doi:10.1177/0022034510376772
更新日期:2010-11-01 00:00:00
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pub_type: 传,历史文章,杂志文章
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更新日期:2010-07-01 00:00:00
abstract::In an attempt to make a dynamic study of the isoelectric point and the chargeability of human dental enamel, an electrochemical approach was utilized. Zeta potential of three kinds of the enamel was measured by a streaming potential method. As a result, these isoelectric points could be decided. ...
journal_title:Journal of dental research
pub_type: 杂志文章
doi:10.1177/00220345780570022701
更新日期:1978-02-01 00:00:00
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journal_title:Journal of dental research
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journal_title:Journal of dental research
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journal_title:Journal of dental research
pub_type: 杂志文章
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journal_title:Journal of dental research
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journal_title:Journal of dental research
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journal_title:Journal of dental research
pub_type: 杂志文章
doi:10.1177/00220345960750021301
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journal_title:Journal of dental research
pub_type: 杂志文章
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abstract::Diet is recognized as one of the most important factors affecting the equilibrium of the oral bacterial flora. Studies related to dental caries development have focused mainly on the effect of carbohydrates. In the present work, using swabbing coupled with an immuno-colony-blot assay, we followed the indigenous oral b...
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abstract::Acidic proline-rich proteins were localized histologically by means of the indirect immunoperoxidase technique in the acinar cells of parotid and submandibular gland sections of both man and Macaca fascicularis. These proteins were also identified as constituents of the long term in vivo-formed acquired pellicle on hu...
journal_title:Journal of dental research
pub_type: 杂志文章
doi:10.1177/00220345800590081201
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abstract::Tempering of dental porcelain by forced convective cooling in air has been shown previously to inhibit the sizes of cracks induced in porcelain surfaces. However, the depth of compressive stress that is produced by tempering of feldspathic porcelain has not been determined. It can be assumed that the potential of temp...
journal_title:Journal of dental research
pub_type: 杂志文章
doi:10.1177/00220345910700020701
更新日期:1991-02-01 00:00:00
abstract::The etiology of dental caries reflects a complex interplay of biochemical, microbial, genetic, social and physical environmental, and health-influencing behavioral factors. This review updates the literature on the efficacy of behavioral approaches to caries prevention for children up to 18 y of age. Included were stu...
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pub_type: 杂志文章,评审
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abstract::A quantitative microprobe analysis was conducted on three commercial amalgams to determine the nature of the phases present. The presence of tin in the Ag-Hg phase (gamma1) was confirmed and Cu-3Sn was found in the original alloy particles. In the dispersant amalgam studied, little Sn-Hg phase (gamma-2) was found and ...
journal_title:Journal of dental research
pub_type: 杂志文章
doi:
更新日期:1975-03-01 00:00:00
abstract::The remodeling of gingival tissue was measured by determining the incorporation of tritiated proline and the disappearance of tritium activity from proline and hydroxyproline for 18 days after administration of label. There was a rapid decrease in the tritium activity from gingiva which was paralleled by a decrease in...
journal_title:Journal of dental research
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abstract::The aim of this systematic review and network meta-analysis was to summarize the direct and indirect clinical evidence on the effectiveness of professionally applied and self-applied topical fluorides in preventing dental root caries. Controlled clinical trials with any follow-up duration were included. MEDLINE, PubMe...
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