Fracture resistance of defective amalgam restorations repaired with a resin-based composite material.

BACKGROUND: Repair is used to increase the longevity of defective restorations, such as large amalgams. The aim of this study was to investigate the fracture resistance and fracture modes of mesio-occlusodistal (MOD) amalgam molar restorations with extensive cuspal fracture repaired or replaced using a bulk-fill resin-based composite material. METHODS: Amalgam restorations were placed in 84 permanent extracted molars and randomly assigned (n = 14) to groups: (1) MOD amalgam, (2) composite repair of 1-cusp fracture and adjacent proximal box, (3) composite repair of 1-cusp fracture, (4) composite repair of 2-cusp fracture, (5) replacement of 1-cusp defect and existing MOD amalgam, (6) replacement of 2-cusp defect and MOD amalgam. Each molar was prepared to simulate the assigned fracture and either repaired or replaced. Specimens were aged and then loaded to fracture. Fracture resistance and fracture modes were recorded. RESULTS: The authors found significant differences (P < .001) between group 4 (1,652.3 N) and groups 5 (3,095.0 N), 1 (2,669.8 N), 6 (2,658.6 N), and 2 (2,442.9 N) as well as between group 3 (2,133.5 N) and group 5 (3,095.0 N). The results of the Fisher exact test showed differences among groups (P < .001), with group 5 having the highest number of nonrestorable fractures as well as higher fracture resistance on average. CONCLUSIONS: Composite material is a viable option for the repair and replacement of cuspal defects, especially in the case of a 1-cusp fracture and 1-cusp fracture involving the adjacent proximal box. PRACTICAL IMPLICATIONS: Within the limitations of this study, the repair of cusp fractures in existing MOD amalgam-restored molars is an appropriate treatment option, although replacement of the defect and existing restoration with resin-based composite will withstand higher forces.

Analysis of the South Australian Aboriginal population using the Global AIMs Nano ancestry test.

We investigate the ability of the 31 SNP loci in the Global AIMs Nano set to distinguish self-declared Australian Aboriginal individuals from European, Oceanic, African, Native American and East Asian populations. Human evolution suggests that Australian Aboriginal individuals came to Australia approximately 50 000 years ago, during the time it made up part of Sahul. Since then the colonisation of Australia by Europeans has meant significant admixture within the Australian Aboriginal population. These two events present themselves in our study with the Aboriginal population creating a continuous genetic cline between the Oceanic and European groups. We also assigned the Aboriginal individuals into their traditional regional groups to determine whether there was any ability to distinguish these from each other. We found similar results to studies using other markers, namely that the more remote regions (that have been less affected by admixture) diverged from the rest. Overall, we found the ability of the GNano system to differentiate self-declared Australian Aboriginal individuals was reasonable but had limitations that need to be recognised if these assignments are applied to unknown individuals.

Improving the quality of the surgical preoperative assessment in a district general hospital.

At Leicester General Hospital, England, patients are assessed by a team of junior doctors for elective colorectal and hepatobiliary procedures. After a number of same day cancellations, a large discrepancy was identified between the findings at the preoperative assessment clinic and the anaesthetic assessment on the day of surgery. After a multidisciplinary meeting was held, three interventions were decided on with an aim to bring the preoperative assessment in line with the anaesthetic assessment. Firstly, a set of guidelines was written and introduced for the junior doctors to use as a reference when assessing patients. Secondly, a proforma was designed specifically to prompt users to include essential details which were being missed in the assessment, having audited 100 patients' notes. Thirdly, a preoperative investigation "calculator" was recommended for each patient to simplify compliance with the National Institute for Health and Care Excellence (NICE) guidance for preoperative assessment. Before and after each intervention was introduced, a cohort of 50 patients were followed looking for differences in findings in the history, examination, investigations, and fitness for surgery between the preoperative assessment in clinic and the anaesthetic assessment on the day of surgery. Initially 68% of patients were compliant for details in the history, 76% for examination, 32% for choice of preoperative investigations, and 100% for fitness for surgery decision. After all three interventions had been introduced, 96% of patients were compliant for history, 94% for examination findings, 88% had the correct choice of preoperative investigations, and 100% had the same decision on fitness for surgery. The interventions described proved to be cheap and effective methods of improving the quality of the preoperative assessment, bringing it in line with the anaesthetic assessment and reducing the risk of same day cancellations.

Medical training in school-based health centers: a collaboration among five medical schools.

School-based health centers (SBHCs) have tremendous untapped potential as models for learning about systems-based care of vulnerable children. SBHCs aim to provide comprehensive, community-based primary health care to primary and secondary schoolchildren who might not otherwise have ready access to that care. The staffing at SBHCs is multidisciplinary, including various combinations of nurse practitioners, physicians, dentists, nutritionists, and mental health providers. Although this unique environment provides obvious advantages to children and their families, medical students and residents receive little or no preparation for this type of practice. To address these deficiencies in medical education, five downstate New York state medical schools, funded by the New York State Department of Health, collaborated to define, develop, implement, and evaluate curricula that expose health professions students and residents to SBHCs. The schools identified core competencies and developed a comprehensive training model for the project, including clinical experiences, didactic sessions, and community service opportunities, and they developed goals, objectives, and learning materials for each competency for all types and levels of learners. Each school has implemented a wide range of learning activities based on the competencies. In this paper, the authors describe the development of the collaboration and illustrate the process undertaken to implement new curricula, including considerations made to address institutional needs, curricula development, and incorporation into existing curricula. In addition, they discuss the lessons learned from conducting this collaborative effort among medical schools, with the goal of providing guidance to establish effective cross-disciplinary curricula that address newly defined competencies.