Synthesis of PH sensitive polymer and evaluation of its efficiency in controlled loading and release of fluoride

Abstract

Introduction: Studies have shown that orthodontic treatments increase the incidence of caries lesions. Today, various studies have suggested adding fluoride to various dental materials such as dental composites, glass ionomer, orthodontic adhesives, or fluoride coating on the surface of orthodontic appliances. One of the best ways to improve this situation is the slow release of fluoride in the oral environment. The purpose of this study is to prepare poly(2-dimethylaminoethyl) methacrylate polymer and to evaluate the ability of carrying and releasing fluoride by this compound.

Materials and methods: Poly (2-dimethylaminoethyl) methacrylate polymer was prepared by atom transfer radical polymerization (ATRP). FT-IR, NMR and SEM tests were used to evaluate the chemical properties and surface properties and morphology of the resulting compound. AT-FTIR in the range of cm-¹ 400-4000 and scanning speed cm-¹ 16 was used to investigate functional groups. MMT was used to investigate toxicity. For the initial load, from poly(2-dimethylaminoethyl) methacrylate samples, 0.02 grams of polymer was added to 10 cc of 0.2% fluoride mouthwash and placed in a shaking incubator at 37°C for 10 minutes. The polymer loaded in the mouthwash was separated using a centrifuge. The loaded polymer was added to artificial saliva (pH=7). The amount of fluoride released was evaluated every day for 10 days. After the initial evaluation, the polymer was recharged with the previous method and separated by centrifugation, and then the amount of fluoride release was evaluated in three cycles and pH 4 and 7 in different time intervals.

Results: The release rate of fluoride at pH 4 was higher than at pH 7. that this difference is significant in the first and second hour. (p value < 0.05)) The maximum release of fluoride in both pH is in the first hour Also, the ability of the polymer to release fluoride does not decrease or increase significantly after each charge in different cycles This polymer has the ability to release fluoride for at least ten days with a single charge, and the process of fluoride release is decreasing during ten days.

Conclusion: The release rate of fluoride from the polymer synthesized at pH 4 was higher than at pH 7; With a single charge, it can release fluoride for at least ten days. Also, the ability to release fluoride does not decrease with recharging.