The objective of this study was to characterize the biomechanical properties of articular cartilage in the superior joint space of the porcine temporomadibular joint (TMJ). These properties and thickness of the disk and fossa cartilage were obtained from eight joints using creep indentation. Five sites per surface were tested to obtain the aggregate modulus, Poisson's ratio, permeability, creep, recovery percentage, and cartilage thickness. Histology was also performed to characterize the orientation of the collagen fibers and the proteoglycan content. It was found that the temporal fossa cartilage was 57% thinner and 50% stiffer than the disk. The aggregate modulus of the porcine TMJ disk and fossa was much smaller, but the permeability of the TMJ disk and fossa was much higher than those of articular cartilage in other joints. It was also noted that the TMJ disk did not fully recover following indentation testing unlike the articular cartilage in other joints. The biomechanical properties of the TMJ disk and temporal fossa obtained in this study are significantly different from those of cartilage present in other diarthrodial joints. This suggests that the function of the fibrocartilage in the superior TMJ space is substantially different from that of hyaline cartilage in other joints.

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Purpose To compare the effectiveness of 2 types of online learning methodologies for improving the patient-safety behaviours mandated in the Joint Commission National Patient Safety Goals (NPSG). Methods This randomized controlled trial was conducted in 2010 at Massachusetts General Hospital (MGH) and Brigham & Women’s Hospital (BWH) in Boston USA. Incoming interns were randomised to either receive an online Spaced Education program (SE) consisting of cases and questions that reinforce over time, or a program consisting of an online slide show followed by a quiz (SQ). The outcome measures included NPSG-knowledge improvement, NPSG-compliant behaviors in a simulation scenario, self reported confidence in safety and quality, program acceptability and program relevance. Results Both online learning programs improved knowledge retention. On four out of seven survey items measuring satisfaction and self reported confidence, the proportion of SE interns responding positively was significantly higher (p<0.05) than the fraction of SQ interns. SE interns demonstrated a mean 4.79 (36.6%) NPSG-compliant behaviors (out of 13 total), while SQ interns completed a mean 4.17 (32.0%) (p=0.09). Among those in surgical fields, SE interns demonstrated a mean 5.67 (43.6%) NPSG-compliant behaviors, while SQ interns completed a mean 2.33 (17.9%) (p=0.015). Focus group data indicates that SE was more contextually relevant than SQ and significantly more engaging. Conclusion While both online methodologies improved knowledge surrounding the NPSG, SE was more contextually relevant to trainees and engaging. SE impacted more significantly on both self reported confidence and the behaviour of surgical residents in a simulated scenario.

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