Ti-SrO metal matrix composites for bone implant materials

Titanium-strontia (Ti-SrO) metal matrix composites (MMCs) with 0, 1, 3 and 5% (weight ratio) of SrO have been fabricated through the powder metallurgy method. Increasing the weight ratio of SrO from 0 to 5%, the compressive strength of Ti-SrO MMCs increased from 982 MPa to 1753 MPa, while the ultimate strain decreased from 0.28 to 0.05. The elastic moduli of Ti-3SrO and Ti-5SrO MMCs were higher than those of Ti and Ti-1SrO MMC samples. Additionally, the micro hardness of Ti-SrO MMCs was enhanced from 59% to 190% with the addition of SrO. The enhanced compression strength and micro hardness of Ti-SrO MMCs were attributed to the Hall-Petch effect and the SrO dispersion strengthening in the Ti matrix. MTS assay results demonstrated that Ti-SrO MMCs with 3% SrO exhibited enhanced proliferation of osteoblast-like cells. Alkaline phosphatase activity of cells was not influenced significantly on the surface of Ti-SrO MMCs compared with pure Ti in a term longer than 10 days. The cell morphology on the Ti-SrO MMCs was observed using confocal microscopy and scanning electron microscopy, which confirmed that the Ti-3%SrO MMCs showed optimal in vitro biocompatibility. This journal is © the Partner Organisations 2014.

Systematic review and quality appraisal of economic evaluation publications in dentistry

Economic evaluation (EE) studies have been undertaken in dentistry since the late 20th century because economic data provide additional information to policy makers to develop guidelines and set future direction for oral health services. The objectives of this study were to assess the methodological quality of EEs in oral health. Electronic searching of Ovid MEDLINE, the Cochrane Library, and the NHS Economic Evaluation Database from 1975 to 2013 were undertaken to identify publications that include costs and outcomes in dentistry. Relevant reference lists were also searched for additional studies. Studies were retrieved and reviewed independently for inclusion by 3 authors. Furthermore, to appraise the EE methods, 1 author applied the Drummond 10-item (13-criteria) checklist tool to each study. Of the 114 publications identified, 79 studies were considered full EE and 35 partial. Twenty-eight studies (30%) were published between the years 2011 and 2013. Sixty-four (53%) studies focused on dental caries prevention or treatment. Median appraisal scores calculated for full and partial EE studies were 11 and 9 out of 13, respectively. Quality assessment scores showed that the quality of partial EE studies published after 2000 significantly improved (P = 0.02) compared to those published before 2000. Significant quality improvement was not found in full EE studies. Common methodological limitations were identified: absence of sensitivity analysis, discounting, and insufficient information on how costs and outcomes were measured and valued. EE studies in dentistry increased over the last 40 y in both quantity and quality, but a number of publications failed to satisfy some components of standard EE research methods, such as sensitivity analysis and discounting.