Parkinson disease (PD) and Alzheimer disease (AD), the two most common neurodegenerative disorders in American adults, are of purely genetic origin in a minority of cases and appear in most instances to arise through interactions among genetic and environmental factors. In this article we hypothesize that environmental exposures in early life may be of particular etiologic importance and review evidence for the early environmental origins of neurodegeneration. For PD the first recognized environmental cause, MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), was identified in epidemiologic studies of drug abusers. Chemicals experimentally linked to PD include the insecticide rotenone and the herbicides paraquat and maneb; interaction has been observed between paraquat and maneb. In epidemiologic studies, manganese has been linked to parkinsonism. In dementia, lead is associated with increased risk in chronically exposed workers. Exposures of children in early life to lead, polychlorinated biphenyls, and methylmercury have been followed by persistent decrements in intelligence that may presage dementia. To discover new environmental causes of AD and PD, and to characterize relevant gene–environment interactions, we recommend that a large, prospective genetic and epidemiologic study be undertaken that will follow thousands of children from conception (or before) to old age. Additional approaches to etiologic discovery include establishing incidence registries for AD and PD, conducting targeted investigations in high-risk populations, and improving testing of the potential neurologic toxicity of chemicals.

As teaching institutions, it is vital for dental schools to collect data on accidental injuries to identify potential problems, improve the quality of care of patients, and educate future practitioners about risk management. Our data reveal important trends concerning such injuries. These data were compiled over a two-year period (2001-03) from accident reports at one dental school. We categorized the accidents as follows: source (instrument causing the injury), recipient of injury, time of day, location within the dental school where the injury occurred, and body part injured. The population examined in this study consisted of predoctoral and postdoctoral dental students, staff, faculty, and patients of the dental school. The majority of injuries occurred in the predoctoral clinic toward the middle to the end of the scheduled clinic periods. The instrument most likely involved was a needle, and the body part most commonly injured was a finger. The collection and analysis of injury data may be used to identify trends that will aid in the prediction and prevention of these injuries and, at a national level, serve as a benchmark that other dental schools can employ to assess their relative frequency of injury.

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Recent efforts have been directed towards utilizing CAD/CAM technology in the education of future dentists. The purpose of this pilot study was to investigate the feasibility of implementing CAD/CAM technology in instruction on preparing a tooth for restoration. Students at one dental school were assigned access to CAD/CAM technology vs. traditional preparation methods in a randomized, crossover design. In a convenience sample of a second-year class, seventy-six of the seventy-nine students volunteered to participate, for a response rate of 96 percent. Two analyses were performed on this pilot data: a primary effectiveness analysis comparing students' competency exam scores by intervention group (intention-to-treat analysis) and a secondary eficacy analysis comparing competency exam scores among students who reported using CAD/CAM versus those who did not. The effectiveness analysis showed no difference in outcomes by intervention group assignment. While student survey results indicated interest in utilizing the technology, the actual utilization rate was much less than one might anticipate, yielding a sample size that limited statistical power. The secondary analysis demonstrated higher mean competency exam scores for students reporting use of CAD/CAM compared to those who did not use the technology, but these results did not reach statistical signiicance (p=0.075). Prior research has investigated the eficacy of CAD/CAM in a controlled educational trial, but this study adds to the literature by investigating student use of CAD/CAM in a real-world, self-study fashion. Further studies should investigate ways in which to increase student utilization of CAD/CAM and whether or not increased utilization, with a larger sample size, would yield signiicant outcomes.