Questions 1 – 5, and 7 above were addressed using saliva and dental plaque inoculums obtained from four adult subjects, all of whom were authors of this manuscript. All four were in good general health, and none had taken antibiotics within the past three months. Three subjects were in good oral health, as determined by the study dentist at the time of initial sampling. However one subject was found to have periodontal disease. We decided to retain the data from that person in the analyses described below, reasoning that his/her clinical status was not likely to bias our ability to validate our oral microcosm model.
A different and larger population of subjects was obtained for the second phase of studies to address Questions 5 – 7. That group consisted of a convenience sample of 10 pediatric patients already participating in a larger ongoing study using HOMIM to compare oral biofilms associated with the margins of amalgam and composite restorations. Each child was examined by the study pediatric dentist, who made a formal caries risk assessment (CAMBRA) (Ramos-Gomez et al., 2010 (link)), which found them to be at high risk for future caries. Two children had active carious lesions at the time of sampling for this study. All children were otherwise in good general health, and had not taken antibiotics within three months of saliva and plaque sampling. Their average age was 8.5 years.
Resting whole saliva was collected by expectoration. The study dentist collected dental plaque inoculums from either the occlusal or buccal margin of existing restorations. A sterile sickle scaler was used, and each sample was immediately deposited into a vial containing 1 ml pre-reduced anaerobic transfer medium (Anaerobe Systems, Morgan Hill, CA, USA). All procedures involving human subjects were approved by the University of Minnesota Institutional Review Board.