Reporting of statistical results in prosthodontic and implantology journals: p values or confidence intervals?

PURPOSE Confidence intervals (CIs) are integral to the interpretation of the precision and clinical relevance of research findings. The aim of this study was to ascertain the frequency of reporting of CIs in leading prosthodontic and dental implantology journals and to explore possible factors associated with improved reporting. MATERIALS AND METHODS Thirty issues of nine journals in prosthodontics and implant dentistry were accessed, covering the years 2005 to 2012: The Journal of Prosthetic Dentistry, Journal of Oral Rehabilitation, The International Journal of Prosthodontics, The International Journal of Periodontics & Restorative Dentistry, Clinical Oral Implants Research, Clinical Implant Dentistry and Related Research, The International Journal of Oral & Maxillofacial Implants, Implant Dentistry, and Journal of Dentistry. Articles were screened and the reporting of CIs and P values recorded. Other information including study design, region of authorship, involvement of methodologists, and ethical approval was also obtained. Univariable and multivariable logistic regression was used to identify characteristics associated with reporting of CIs. RESULTS Interrater agreement for the data extraction performed was excellent (kappa = 0.88; 95% CI: 0.87 to 0.89). CI reporting was limited, with mean reporting across journals of 14%. CI reporting was associated with journal type, study design, and involvement of a methodologist or statistician. CONCLUSIONS Reporting of CI in implant dentistry and prosthodontic journals requires improvement. Improved reporting will aid appraisal of the clinical relevance of research findings by providing a range of values within which the effect size lies, thus giving the end user the opportunity to interpret the results in relation to clinical practice.

Mechanical Loading Promoted Discogenic Differentiation of Human Mesenchymal Stem Cells Incorporated in 3D-PEG Scaffolds with RhGDF5 and RGD

Hydrogels have been described as ideal scaffolds for cells of 3D tissue constructs and hold strong promises with respect to in vitro 3D-cell-culture, where cells are isolated from native extracellular matrix (ECM). Synthesized polyethyleneglycol (PEG) hydrogels are appealing with regard to potential for cell therapy or as vehicles for drug delivery or even to regenerate tissue with similar hydrogel-like properties such as the nucleus pulposus of the intervertebral disc (IVD). Here, we tested whether incorporation of RGD motive would hinder discogenic differentiation of primary bone marrow-derived human mesenchymal stem cells (hMSCs) but favor proliferation of undifferentiated hMSCs. HMSCs were embedded in +RGD containing or without RGD PEG hydrogel and pre-conditioned with or without growth and differentiation factor-5 (rhGDF-5) for 13 days. Afterwards, all hMSCs-PEG gels were subsequently cyclically loaded (15% strain, 1Hz) for 5 consecutive days in a bioreactor to generate an IVD-like phenotype. Higher metabolic activity (resazurin assay) was found in groups with rhGDF5 in both gel types with and without RGD. Cell viability and morphology measured by confocal laser microscopy and DNA content showed decreased values (~60%) after 18 days of culture. Real-time RT-PCR of an array of 15 key genes suspected to be distinctive for IVD cells revealed moderate response to rhGDF5 and mechanical loading as also shown by histology staining. Preconditioning and mechanical loading showed relatively moderate responses revealed from both RT-PCR and histology although hMSCs were demonstrated to be potent to differentiate into chondrocyte-progenitor cells in micro- mass and 3D alginate bead culture.

Current State of Reporting Pain Outcomes in Cochrane Reviews of Chronic Musculoskeletal Pain Conditions and Considerations for an OMERACT Research Agenda.

OBJECTIVE To assess the current state of reporting of pain outcomes in Cochrane reviews on chronic musculoskeletal painful conditions and to elicit opinions of patients, healthcare practitioners, and methodologists on presenting pain outcomes to patients, clinicians, and policymakers. METHODS We identified all reviews in the Cochrane Library of chronic musculoskeletal pain conditions from Cochrane review groups (Back, Musculoskeletal, and Pain, Palliative, and Supportive Care) that contained a summary of findings (SoF) table. We extracted data on reported pain domains and instruments and conducted a survey and interviews on considerations for SoF tables (e.g., pain domains, presentation of results). RESULTS Fifty-seven SoF tables in 133 Cochrane reviews were eligible. SoF tables reported pain in 56/57, with all presenting results for pain intensity (20 different outcome instruments), pain interference in 8 SoF tables (5 different outcome instruments), and pain frequency in 1 multiple domain instrument. Other domains like pain quality or pain affect were not reported. From the survey and interviews [response rate 80% (36/45)], we derived 4 themes for a future research agenda: pain domains, considerations for assessing truth, discrimination, and feasibility; clinically important thresholds for responder analyses and presenting results; and establishing hierarchies of outcome instruments. CONCLUSION There is a lack of standardization in the domains of pain selected and the manner that pain outcomes are reported in SoF tables, hampering efforts to synthesize evidence. Future research should focus on the themes identified, building partnerships to achieve consensus and develop guidance on best practices for reporting pain outcomes.