ORAL ENDOTOXIN IN HEALTHY-ADULTS

This article presents a study that measured oral endotoxin levels in h ealthy persons with the Limulus amoebocyte lysate microassay. Only you ng nonsmoking adults with a healthy dentition measured with the plaque index and a good level of oral hygiene based on a twice-daily (mornin g and evening) tooth-brushing regimen were admitted to this open study . Each person was required to provide two oral washings of 10 mi steri le saline solution 1 week apart. Only those volunteers without oral ca rriage of aerobic gram-negative bacilli were enrolled in the baseline study. A total of 15 healthy adults with a median age of 29 years (ran ge, 25 to 43 years) were included in the trial. The mean plaque score of the group was 1.2 +/- 0.1. They all maintained a twice-daily tooth- brushing regimen unaltered throughout the sampling period. A total of 30 mouth rinses were studied. None of the samples yielded potential pa thogens including aerobic gram-negative bacilli, Staphylococcus aureus and yeasts; a culturing technique based on preenrichment in nutrient medium was used. Data showed mean oral endotoxin levels of 20 ng per m i of mouth rinse; the aerobic E. coli endotoxin was used as the classi cal standard. This is equivalent to 1 mg of anaerobic endotoxin per mi of undiluted saliva after correcting for the 10 to 10(2) dilution fac tor of the mouth rinse itself and for the 10(3) times less sensitivity of anaerobic endotoxin in the Limulus amoebocyte lysate-assay. The di scussion includes the physiologic and clinical benefit of the low endo toxicity of anaerobic gram-negative flora apart from the technical asp ects of both culture and endotoxin assays used in the study.