Recovery of putative periodontal pathogens from curette sampling at different depths of periodontal lesions: an in vivo cross-sectional clinical study.

OBJECTIVE: The aim of this study was to evaluate the effect of the depth of curette sample collection from periodontal lesions on the recovery of putative periodontal pathogens using real-time polymerase chain reaction (PCR).

METHODS: Twenty-two periodontal pockets 6 to 8 mm deep with bleeding on probing at a single-rooted tooth were sampled, yielding 66 separate samples. Curette samples were obtained at three different levels of the periodontal lesion (orifice, shallow--2 mm into the pocket; or base of lesion), and processed using PCR to identify 10 periodontal pathogens. The chi-square procedure was used to determine whether probe depth affected the distribution of bacterial counts observed. A repeated measures analysis of variance tested the hypotheses related to level of probe and microorganism on mean rank of bacterial counts.

RESULTS: The effect of probe level on mean bacterial counts depends on the type of microorganism. Likewise, the effect of microorganism type on mean bacterial counts significantly depends on probe level, where sampling from 2 mm into the periodontal pocket was found to yield significantly higher results than sampling from the orifice. Overall mean counts of pathogenic microorganisms were found to differ significantly across the three probe depths. The microorganisms differed in their observed levels over all three probe levels. Further analysis found several significant differences that characterize the nature of the interaction between probe level and microorganism type.

CONCLUSION: There is significant difference in the amount of putative periodontal pathogens at varying depths of the pocket when sampled with a periodontal curette.