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- Jefferies, Steven R., et al.
(author)
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Prospective Observation of a New Bioactive Luting Cement : 2-Year Follow-Up
- 2012
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In: Journal of Prosthodontics. - : John Wiley & Sons. - 1059-941X .- 1532-849X. ; 21:1, s. 33-41
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Journal article (peer-reviewed)abstract
- Purpose: A pilot study was conducted to determine the 2-year clinical performance of a new bioactive dental cement (Ceramir C&B, formerly XeraCem) for permanent cementation. Materials and Methods: The cement used in this study is a new formulation class, a hybrid material comprising calcium aluminate and glass ionomer. Thirty-eight crowns and fixed partial denture (FPD) abutments were cemented in 17 patients. Thirty-one of the abutment teeth were vital, 7 nonvital. Six reconstructions were FPDs comprising 14 abutment teeth (12 vital/2 nonvital). A two-unit fixed splint was also included. Preparation parameters and cement characteristics (dispensing, working time, seating characteristics, ease of cement removal) were recorded. Baseline and postcementation data were recorded for marginal integrity, marginal discoloration, secondary caries, retention, and gingival inflammation. Tooth sensitivity was assessed at pre- and postcementation time points using categorical and visual analogue scale (VAS) assessment measures. Results: Mixing of the cement was reported as “easy.” Clinical working time for this cement was deemed acceptable. Assessment of seating characteristics indicated all restorations were seated completely after cementation. Cement removal was determined to be “easy.” Fifteen of 17 subjects were available for 1-year recall examination; 13 patients were available for the 2-year recall examination. Restorations at 2-year recall examination included 17 single-unit, full-coverage crown restorations, four 3-unit FPDs comprising 8 abutments, and one 2-unit splint. No retentive failures or sensitivity were recorded at 2-year recall. Marginal integrities of all restorations/abutments at 2 years were rated in the “alpha” category. Average VAS score for tooth sensitivity decreased from 7.63 mm at baseline to 0.44 mm at 6-month recall, 0.20 mm at 1-year recall, and 0.00 mm at 2-year recall. The average gingival index score for gingival inflammation decreased from 0.56 at baseline to 0.11 at 6-month recall, then 0.16 at 1-year recall, and 0.21 at 2-year recall. Conclusions: Two-year recall data yielded no loss of retention, no secondary caries, no marginal discolorations, and no subjective sensitivity. All restorations rated “alpha” for marginal integrity at the 2-year recall. After periodic recalls up to 2 years, the new bioactive cement tested thus far has performed favorably as a luting agent for permanent cementation.
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- Lööf, Jesper, et al.
(author)
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A comparative study of the bioactivnity of three materials for dental applications
- 2008
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In: Dental Materials. - : Elsevier BV. - 0109-5641 .- 1879-0097. ; 24:5, s. 653-659
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Journal article (peer-reviewed)abstract
- Objectives. The aim of this work was to investigate the in vitro bioactivity of two different experimental dental luting cement formulations based on calcium aluminate (CA) in comparison with glass ionomer cement (GIC). One of the CA-based formulations was a hybrid between CA and GIC. Methods. Samples were submerged in phosphate buffered saline and stored at 37 degrees C for four periods of time: 1 h, 1 day, 7 days and 4 weeks. After storage the samples were analyzed in order to investigate if a surface layer of hydroxyapatite had formed. The analysis techniques used included grazing incidence X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and transmission electron microscopy. Results. Both the CA-containing formulations were found to be bioactive. The highest degree of bioactivity was found on the sample with only CA as active substance. A relatively thick and totally covering layer was already formed after 24 h. On the hybrid material hydroxyapatite was found after 7 days. The GIC showed no bioactivity during the test period. Significance. The utilization of a bioactive material for tooth restorations will give an opportunity for remineralization and a natural and durable seal of the tooth-material interface. Materials based on CA exhibit bioactivity.
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- Lööf, Jesper, 1977-
(author)
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Calcium-Aluminate as Biomaterial : Synthesis, Design and Evaluation
- 2008
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Doctoral thesis (other academic/artistic)abstract
- In this thesis different aspects of calcium-aluminate (CA) as biomaterial are presented. Calcium aluminate is a chemically bonded ceramic with inherent properties making it suitable for use as biomaterial in some applications. In this thesis the emphasis is put on the basic chemical, physical and mechanical properties that may be achieved using the CA system as well as synthesis of the CA raw material. The basis for using CA in any application is the synthesis of the raw material. Different synthesis routes for producing CA are presented with focus on high temperature routes and the micro-structural and phase development during synthesis. As a base for further understanding of the CA properties a thorough outline of the reaction chemistry for CA is presented also including a description of how the reactions may be controlled and how formulations can be designed. The surface reactions of CA when subjected to simulated body fluid showed that CA is in vitro bioactive. An in vivo study in teeth also indicates that CA produces apatite at the tooth material interface. Dental materials are subjected to a harsh environment in the mouth with high mechanical forces, erosion and thermal changes. Also the demands on precise handling characteristics are high. For these reasons the in vitro evaluation of physical and mechanical properties are important. In this work several mechanical and physical properties of Ca-based formulations for dental applications has been tested using different methods. Some attention is also put on the specific characteristics of CA and the difficulties that arise when new material classes needs to be tested according to consensus standard methods. Finally studies on a CA-based formulation intended for Vertebroplasty is presented. The studies include basic mechanical properties as well as testing the material in an in vitro model utilising synthetic cancellous bone.
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- Unosson, Erik, et al.
(author)
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Antibacterial Properties of Dental Luting Agents : Potential to Hinder the Development of Secondary Caries
- 2012
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In: International Journal of Dentistry. - : Hindawi Publishing Corporation. - 1687-8736 .- 1687-8728. ; 2012, s. 529495-
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Journal article (peer-reviewed)abstract
- A modified direct contact test was used to evaluate the antibacterial properties of four commercially available dental luting agents (RelyX Unicem, Ketac Cem, Ceramir Crown & Bridge and Harvard Cement) and two reference materials (glass-ionomer cement and calcium aluminate cement) compared to a negative-control material (PMMA). Streptococcus mutans bacteria were placed in direct contact with specimens that had been aged for 10 min, 1 day, and 7 days, in order to test the antibacterial properties of the materials. A metabolic assay containing resazurin was used to quantify the amount of viable bacteria remaining after the direct contact tests. The effects of pH and fluoride on bacteria proliferation were also evaluated. Strongest antibacterial properties were found for calcium aluminate cement, followed by Ceramir Crown & Bridge and RelyX Unicem. Ketac Cem, Harvard Cement, and the reference glass-ionomer cement showed bacteria content either higher than or not significantly different from the PMMA control in all instances. pH levels below 6.3 and above 9.0 were found to have negative effects on bacterial proliferation. No correlation between either acidic materials or fluoride release and antibacterial properties could be seen; rather, basic materials showed stronger antibacterial properties.
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