The association of carious dentin microflora with tissue changes in human pulpitis.

Correlations were sought between the number and type of microorganisms recovered from sampled carious dentin and the cellular responses observed in dental pulpal tissues from a sample of 65 vital, carious teeth extracted from adult humans who had declined the option of tooth restoration. Standardized homogenates of carious dentin were plated using selective and nonselective media under anaerobic and microaerophilic conditions. Pulpal responses were characterized histopathologically on the basis of the nature of the cellular infiltrate and the extent of degenerative changes. A significant association between the number of Prevotella intermedia and Prevotella melaninogenica in carious dentin and extensive, principally mononuclear, inflammatory infiltration was evident despite a high degree of complexity and intersubject variability in the microbial flora. There was no apparent association between other microorganisms or total microbial load and the histopathological category.