Real time polymerase chain reaction analysis in the patients treated with fixed appliances after the orthodontic treatment: A follow-up study

This study aimed to compare the changes in the salivary cariogenic bacteria levels using qPCR and oral hygiene status after orthodontic treatment with fixed appliances during the retention phase concerning the patient and treatment variables. In this study, saliva samples were collected from 35 patients before debonding (T₀) and after five weeks of debonding on retention (T₁). The saliva samples were collected to extract the genomic DNA, and using specific probes and primers using real-time polymerase chain reaction was performed to analyze the changes in S. mutants, S. sobrinus, L. Casei after orthodontic treatment with fixed appliances. Additionally, OHI levels were also measured. The current study confirms the statistical association between T0 and T1 groups of S. mutants (p = 0.028) and S. sobrinus (p = 0.049). However, a lack of association was observed with L. Casei (p > 0.05). The number of bacteria was decreased from the T₀ group and increased in the T₁ group in Streptococcus mutants (S. mutants) and Streptococcus Sobrinus (S. sobrinus) while in Lactobacillus Casei (L. Casei) it was vice versa between T₀ and T₁ groups. The Oral Hygiene Levels (OHI) levels were also found to be statistically associated (p = 0.003). This study concludes that comparing the salivary cariogenic bacterial levels at T₀ (before debonding of fixed orthodontic appliances), with T1 (Five weeks after the debonding), and despite better oral hygiene, there was increase in salivary S mutants and S sobrinus levels. The current study suggested that orthodontic patients need careful hygienic procedures during the retention period. Future studies are recommended with additional follow-up and a large sample size.