The polymerase chain reaction was used for the detection ofHelicobacter pylorifrom subgingival plaque in 336 periodontitis patients. A pair of primers derived from theH. pyloriurease gene A served to amplify a targeted 411‐bp fragment of genomic DNA. This technique permitted the detection of as few as 60H. pyloricells. Paper point samples from 3 deep periodontal pockets per patient were immersed in 1 ml of phosphate‐buffered saline or distilled water, DNA was solubilized by detergent/protease method, 3.7 μl or 37 μl of lysate supernatant was used as template, and the amplification product was analyzed in 1% agarose gel containing ethidium bromide. Each experiment included purified DNA and cell lysate ofH. pylorias positive controls. The presence of bacteria in the sample was verified by a primer pair common to prokaryote 16S rRNA. The present study did not reveal the specific polymerase chain reaction amplification product characteristic ofH. pylori.We conclude that periodontal pockets do not constitute a natural reservoir forH. p
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