Hubbell et al. (1) estimated the number of Amazonian tree species threatened with extinction due to habitat loss predicted under 2 development scenarios for the Brazilian Amazon (2). Unfortunately, their analysis suffers from several critical weaknesses that render the results suspect, if not meaningless, for conservation. Hubbell et al. (1) model species ranges as circles or ellipses, the area...

Current literature supports the use of powered instrumentation over traditional hand instrumentation. The objective of scaling and root planing is the complete removal of plaque and calculus from root surfaces. While this is unrealistic, the accepted end-point is a smooth, glassy root surface during periodontal instrumentation. This often has resulted in overinstrumentation and excessive remova...