Comparison of Bisfenol-A levels from fixed lingual retainers, essix plates and hawley appliances used for retension after orthodontic treatment

Introduction: Bisphenol-A (BPA) is a chemical found in plastics and epoxy resins and exposure has increased with the increased use of polycarbonate plastics. In 1996, BPA release was detected in dental materials and numerous studies have been conducted on the subject since then. While no measurable levels of BPA were found in blood and urine, it was found in saliva samples, but below the daily intake dose. Materials that cause BPA release in dentistry include composite adhesives, acrylics and essix aligners exposed to heat. This study aims to compare BPA levels in patients using different retention methods after orthodontic treatment. Materials and Methods: This study was conducted at Aydın Adnan Menderes University Faculty of Dentistry and 120 volunteer participants were randomly divided into four groups. The groups received bis-GMA-containing composite retainer, bis-GMA-free composite retainer, essix plate and hawley appliance, respectively. Saliva samples were taken from the participants at four different times and BPA levels were measured. The samples were taken one day after the debonding procedure (T0), 1 hour after the application of the retainer (T1), 1 week (T2) and 1 month (T3). Laboratory analyses and statistical evaluations were performed. Results: Statistically significant differences were found between T0-T1, T0-T2, T1-T3, T2-T3 times in the retainer group applied with composite containing Bis-GMA and in the group of retainer applied with composite without Bis-GMA (p=0.001). The differences between T0-T1, T0-T2, T1-T2, T1-T3, T2-T3 in the Essix plaque group and the hawley appliance group were statistically significant (p=0.001). The highest BPA level was found at T2 time in all groups. In the comparison between the groups, the mean BPA level at T1 and T2 times; It was found statistically different between Group1-Group4, Group2-Group3, Group2-Group4 (p=0.001). Although the highest BPA level was found in the retainer group with Bis-GMA composite and the retainer group with Bis-GMA-free composite, there was no statistically significant difference between these two groups. Conclusion: The results show that there were significant increases in salivary BPA levels after retainer application in all groups. The retainer groups with composites with and without Bis-GMA showed the highest increase in BPA levels. Increases in salivary BPA levels were also detected in Essix plate and hawley appliances. Decreases in BPA levels were observed 1 month after the use of retainers. Although the study detected increases in BPA levels below the daily intake dose, it is of concern due to its potential effects on human health. The use of BPA-free materials and the design of retention appliances to minimize exposure are recommended. In addition, additional precautions should be taken by patients and healthcare personnel to protect against BPA exposure.