Comparative Evaluation of Salivary Bisphenol-A Levels in Patients With Fixed Lingual, Hawley and Vacuum-formed Retainers

The aim of this study; to measure the BPA release amount of fixed lingual retainers applied with Bis-GMA-containing composite , fixed lingual retainers applied with Bis-GMA-free composite, vacuum-formed and hawley retainers which used for retention after orthodontic treatment to evaluate whether they are risk factors for the patient and to compare BPA releases.

Study method and data collection techniques: In this study, individuals will be selected from the patients who will be treated at Aydın Adnan Menderes University Faculty of Dentistry, Department of Orthodontics between July 2021 and July 2022, whose orthodontic treatment will be completed. These patients will be randomly divided into four groups according to the type of retention appliance to be chosen: those who are applied a fixed lingual retainer with a bis-GMA-containing composite, those with a fixed lingual retainer with a bis-GMA-free composite, those with an vacuum formed retainers, and those with a hawley retainers. After the debonding of the fixed attachments at the end of the treatment appointment, the retention appliances will be applied 1 day later so that BPA, which is released from the resin adhesives used to bond the attachments, does not affect the study data. Saliva samples will be taken from the patients before the appliance is inserted, 1 hour, 7 days and 30 days after the appliance is inserted.

Patients who are scheduled to complete their orthodontic treatment between July 2021 and July 2022 and will be debonded will be included in the study. Inclusion criteria for the study; not to have any systemic diseases, not to smoke, not to work in jobs where they will be exposed to chronic BPA release, such as gas station-construction site or acrylic-related jobs. Selected patients will be randomly divided into four groups. Randomization will be done through the website www.random.org. Fixed lingual retainer applied with composite containing Bis-GMA will be applied in the first group, fixed lingual retainer applied with composite without Bis-GMA in the second group, vacuum formed retainers in the third group and hawley retainers in the fourth group. 120 patients, including 30 individuals in each group, will be included in the study. The number of men and women in each group will be equal. Patients who have undergone debonding will be given an appointment to wear retention appliances one day later. Patients will be advised to brush their teeth routinely, including the appointment day, and not to consume any food or drink at least 2 hours before the application. In addition, due to the effect of many drugs on salivary secretion, if patients use drugs, they will be told to take them at least 8 hours before the application. Saliva samples for BPA release will be taken before appliance insertion, 1 hour after, 7 days and 30 days after insertion. Samples taken will be stored in polypropylene tubes. All samples taken will be stored at -80 degrees until analysis. The sample will be processed by mixing 5ml saliva with an equal amount of ethanol and vortexing it. It will be centrifuged at 3000 rpm for 15 minutes. The ultimately processed sample will be injected into the instrument and analyzed by liquid chromatography.

Eligibility Criteria:
Inclusion Criteria:

* be between the ages 10-18
* absence of any systemic disease
* good oral hygiene
* completion of orthodontic treatment
* non smoker
* Not working in jobs where they will be exposed to chronic BPA release, such as gas station construction site or acrylic related jobs

Exclusion Criteria:

* be under 10 years or over 18 years
* any systemic disease
* poor oral hygiene
* ıncomplete orthodontic treatment
* being a smoker
* working in jobs where they will e exposed to chronic BPA release, such as gas station construction site or acrylic related jobs