Effect Of Fixed Orthodontic Treatment On Oral Microbiome:Results From Next Generation 16S RRNA Sequencing

Objective: The aim of the present study was to investigate whether fixed orthodontic treatment influences the oral microbiome by using Next Generation 16 S r RNA Sequencing.Materials and Methods: This study was conducted on forty Chinese patients who undergone fixed orthodontic treatment at Dalian Stomatological hospital affiliated of Dalian Medical University between October 2017 and April 2018.The patients considered three consecutive follow-ups to collect one hundred twenty samples,with the average age 20.18 + 7.21.All subjects were examined,and the oral swabs were taken at three intervals.The first interval was at the baseline immediately before placing the fixed orthodontic appliances(Group A),the second interval was one month after placement of the fixed orthodontic appliances(Group B),and the third interval was three months after placement of the appliances(Group C).Genomic DNA was extracted from all the samples and subjected to Illumina Miseq for detection of the changes in the oral microbiome composition and structure.The V3-V4 hypervariable region of the 16 S r RNA was amplified from a genomic DNA using primers 515 F and 806 R.The amplicons were normalized,pooled as well as sequenced using the Illumina Miseq desktop sequencer(2 × 300)bp paired end run.Results This study showed that there was no significant difference in the oral microbiome among the three groups.During the follow-up period,we detected an increased in the oral microbiome abundance at Group B,but it was gradually return to its baseline range after 3 months of treatment.The increase may be due to difficulty in maintaining good oral hygiene at the beginning of fixed orthodontic treatment cause of dental pain or inappropriate tooth brushing.However,this increase was statistically non-significant(P> 0.05).The potentially bacterial pathogenic increased in(Group B)but without significant difference after one month of placing fixed orthodontic treatment comparing to the(Group A)but decreased in the relative abundance at(Group C).Furthermore,we did not observe a significant increase in the abundance of the well-known genus Selenomonas,Prevotella,Tannerella,Leptotrichia which oftentimes correlated with an unhealthy periodontium and are significantly enriched in the periodontal disease;Whilst,our findings observed a slightly increase in the bacterial genus Rothia,Lautropia,and Actinomyces which are generally associated with oral health.Conclusion: The present study revealed that fixed orthodontic treatment did not cause significant changes in the oral microbiome between the three intervals,as well as it did not increase the risk of high levels of bacterial genus linked with periodontal pathogens.However,a slight fluctuation in the abundance of oral microbiome.Therefore,proper daily oral hygiene should be recommended for orthodontic patients from the beginning of the fixed orthodontic treatment to overcome any possible detrimental effects that could produce by dental plaque accumulation...