Comparative evaluation of salivary microbial levels of red complex bacteria in patients wearing three different types of fixed lingual retainers: a clinical study

Abstract

Introduction: One of the major challenges for orthodontists is the long-term stability of orthodontic treatment. This has urged orthodontists to seek methods to ensure stable results following the completion of orthodontic treatment. Incisor crowding is reported to occur in follow-up stages of orthodontically treated patients. Maintenance of incisor alignment following orthodontic treatment has led to the development of retainers (removable and fixed). Fixed lingual retainers have been criticized for their potential to compromise the periodontal status, due to accumulation of plaque and calculus along the retainer wire. Objectives: The aim of this study was to evaluate and compare salivary microbial levels of the “Red Complex Bacteria” after orthodontic treatment with fixed appliances, during the retention period using three different types of fixed lingual retainer wires. Materials and methods: 30 patients who have completed orthodontic treatment and met the inclusion criteria were randomly divided into 3 groups with 10 patients each. Fixed lingual retainers (Retainium or Penta-One or Bond-a-Braid wire) were bonded to the lingual surfaces of the six anterior teeth. Saliva samples were collected at debonding (T0), 4 weeks after debonding (T1) and 8 weeks after debonding (T2). Saliva samples were stored at -80o Celsius followed by PCR testing, One- way ANOVA test followed by Tukey's post hoc Test was used to compare the mean PCR values of P. gingivalis, T. denticola and T. forsythia (Red Complex Bacteria) between 3 groups at different time intervals. Repeated measures of ANOVA test followed by Bonferroni's post hoc Test was used to compare the mean PCR values of various microorganisms between different time intervals in each group. Results: The PCR test results demonstrated that the highest Red Complex Bacterial growth was observed in Group 3 (Bond-a-Braid wire) followed by Group 2 (Penta-One wire). Whereas the least Red Complex Bacterial growth was observed in Group 1 (Retainium wire) at different time intervals (T0, T1, T2). The maximum growth of P. gingivalis was observed at debonding (T0). The least growth of P. gingivalis was seen at 8 weeks after debonding (T2). Similarly, T. denticola and T. forsythia showed highest values at debonding (T0), while lowest values were observed at 8 weeks after debonding (T2). Conclusion: The present study concluded that there is statistically significant difference (p<0.001) in the salivary microbial levels (Red Complex Bacteria) with different types of fixed lingual retainer wires at three time intervals (T0, T1 and T2).