Dr. Fire-stone complains that the key, at least to him, piece of information in our study (that is, the mean age of the sample) was not prominently mentioned in the abstract. His obvious concern highlights the risk if the dissemination of new clinical knowledge in dentistry continues to be based on information gleaned from abstracts and summaries, rather than on thorough review and consideration of full descriptions of scientific studies.
The information describing the sample age, which Dr. Fire-stone characterizes as "casually" mentioned "far into the body of the article," appears early (in the second paragraph) in the Methods section, the appropriate and expected location for information describing the sample for a study.
The conclusion that Dr. Fire-stone describes as presenting "this age-qualifying factor" and as appearing "only at the end of this seven-page article" appears by logical convention at the end of the paper and alerts the reader that the authors are unwilling to generalize the findings beyond the age range represented by the study sample.
That the actual age of the study sample is not described in the abstract should not be surprising, since the length of abstracts in JADA, as in all clinical journals, is severely restricted. The point is that almost any study will raise a number of key methodological issues, that these issues will be different for different readers and that not all will be addressed in a study’s abstract.
Abstracts are presented as a convenience to busy readers who wish to screen articles to identify those they wish to scrutinize more closely, not as a means of informing clinicians of new scientific information.
More broadly, Dr. Firestone’s letter highlights a pervasive problem in clinical dentistry. The problem is the quality of the evidence supporting much of clinical treatment. Dr. Firestone cites a case study presented in a 1963 letter as evidence that our findings cannot be applied to first molars extracted at an early age.
The assumption that the citation of a single case constitutes acceptable clinical evidence exemplifies the unstable basis for much of what Dr. Firestone refers to as "basic tenets" of dentistry. If dentistry is to progress as a scientifically based profession, it must begin to examine the evidence supporting each of these basic tenets. Often, as in our paper, the evidence is less than it appears.
