Exploring the variation of oral microbiota in supragingival plaque during and after head-and-neck radiotherapy using pyrosequencing

Abstract Objective The aim of this article was to study the variation in oral microflora of the subgingival plaque during and after radiotherapy. Design During and after radiotherapy, microbial samples were collected at seven time points (early stage, medium stage, and later stage of radiotherapy, and 1 month, 3 months, 6 months, and 1 year after radiotherapy) in three subjects for a total of 21 samples. Polymerase chain reaction (PCR) amplification was carried out on the 16S rDNA hypervariable V1–V3 region, and then the PCR products were determined by high-throughput pyrosequencing. Results The rarefaction curve indicating the richness of the microflora demonstrated that the number of operational taxonomic units (OTUs) was in decline from the early stage of radiotherapy to the time point 1 month after radiotherapy and then trended upward. The Shannon diversity index declined during radiotherapy (ranging from 4.59 to 3.73), and generally rose after radiotherapy, with the lowest value of 3.5 (1 month after radiotherapy) and highest value of 4.75 (6 months after radiotherapy). A total of 120 genera were found; five genera ( Actinomyces , Veillonella , Prevotella , Streptococcus , Campylobacter ) were found in all subjects across all time points. Conclusion The richness and diversity of oral ecology decreased with increased radiation dose, and it was gradually restored with time.