Evaluation of salivary and oral cell collection methods for genomic DNA extraction

Abstract

The use of saliva and oral cells as sources of biological material has gained attention, due to advantages such as facility, non-invasiveness, and great patient acceptance. The objective of the study was to compare four different types of saliva and oral buccal cell collecting methods for genomic DNA extraction: (1)Expectoration of saliva, (2)Expectoration of saliva with lingual stimulation, (3)Scraping with cytological brush, and (4)Scraping with cytological brush and expectoration of saliva. The sample was composed of students and employees from the Dental School of the Federal University of Rio de Janeiro (n = 20, 10 men and 10 women with mean age of 47.60 ± 15.70 and 20.50 ± 2.1, respectively). The collections were performed with an interval of at least one day between them and the participants were instructed to stay for less than 30 minutes without eating food and brushing teeth. Samples were stored at -20°C until DNA extraction was performed using a commercially available kit (Qiagen®). Differences in DNA yield between methods were test for statistical significance with an alpha of 0.05. No sexual dimorphism was observed in relation to the concentration of DNA (p=0.76), age (p=0.91), and ethnicities (p=0.72). There was no significant difference between the collection methods in relation to the quantity and purity of the extracted DNA (p≥0.05). All methods gave lower DNA yields than the ones obtained from blood or saliva collected through comercial kits and may be carefully use for clinical diagnostic purposes or for research experiements requiring higher DNA concentrations.