Human herpesvirus 6 as a possible cause of pneumonia

BACKGROUND: In biological studies of periodontitis, there has been long-standing confusion between the ubiquitous phenomena of inflammation and the essential criterion of attachment loss. This is partly attributable to inadequate methods of clinical measurement, but seems also to be a consequence of an unproven and usually unstated assumption that the same biological processes underlie both inflammation and attachment loss. Developments in unidimensional clinical probing methods have helped in studies of periodontal treatment. However, such methods are intrinsically unsuitable in studies of periodontal diseases, and may have given them a false sense of security. the confusion has been compounded by inappropriate use of statistical techniques in an attempt to solve problems which do not arise from mathematical models but are intrinsic to measurement methods. OBJECTIVE: This paper is a clinician's attempt to state the current difficulties and suggest some ways forward, including the development of three-dimensional measurement, non-invasive probing, and several objectives for biochemical, microbiological and immunological research.