Preliminary Evaluation of the Use of Methylene Blue, a Redox Dye, in the Treatment of Chronic Periodontitis

Abstract

It is well established that chronic periodontitis is associated with the accumulation of subgingival plaque [1]. The microflora of this plaque is extremely complex and varies from niche to niche. Thus, the sparse subgingival flora of the healthy crevice consists largely of aerobic and facultative bacteria (mainly gram-positive cocci and rods). In gingivitis, the relative numbers of gram-negative cocci and rods increase, and in periodontitis, there is a further increase in the number of anaerobic gram-negative rods. [2]. Some of these organisms have been strongly implicated in the pathogenesis of periodontal disease; Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Wolinella recta, and spirochetes are examples. Current methods of treating periodontitis involve mechanical removal of plaque, with occasional adjunctive chemical therapy with agents such as chlorhexidine or the tetracyclines [3, 4]. However, antimicrobial agents are not the only means of controlling the growth of anaerobic bacteria. Survival and growth of such organisms in an ecosystem is, in part, dependent on the existence of a low redox potential [5-7]. Studies have shown that redox potentials as low as -300 mV exist in periodontal pockets, thereby enabling the survival of oral anaerobic bacteria in this ecosystem [8, 9]. The redox potential of the healthy gingival crevice has been measured by Kenney and Ash to be +70 mV [8], with a small population of anaerobic bacteria. Thus, by raising the redox potential of the periodontal pocket, it should be possible to create an environment incompatible with the growth of anaerobic periodontal pathogens. Various substances are available that might achieve this, such as redox dyes (like methylene blue) and transition metal ions (like ferric ions) [10, 11]. The aim of the present study was to determine whether