Release of calcium phosphate from modified orthodontic primer for prevention of white spot lesions

Background: One of the side effects of orthodontic treatment is the development of white spot lesions that can be prevented by promoting release of calcium and phosphate ions from orthodontic adhesive primer. Aims: This study aims to develop an orthodontic primer modified with nano-chitosan/calcium phosphate as a drug carrier to promote controlled and slow release of the loaded calcium phosphate for remineralization of demineralized enamel. Materials and methods: Transbond™ XT adhesive primer was modified by 5% and 10% nano-chitosan loaded with calcium phosphate and characterized by field emission scanning electron microscopy (FESEM). The cumulative release of calcium phosphate from modified orthodontic primer over 4 week intervals (7th, 14th, 21st, and 28th days) was measured by a double beam UV-visible spectrophotometer. The disc samples were immersed in 5 ml of distilled water in a plastic container. Cumulative material release was calculated using calibration graphs based on the λ max of calcium phosphate at 240 nm. The results were analyzed using descriptive statistics and independent samples t-test to compare the 5% and 10% Ch/CP concentrations at each week interval. Statistical significance was set at P < 0.05. Results: The mean value of both 5% and 10% nano-chitosan/ calcium phosphate primer groups showed an increase in the release of calcium phosphate concentration over time, indicating a controlled sustained release process. Furthermore, the cumulative release was higher by 10% compared to 5% chitosan/ calcium phosphate modified primer. The Independent samples t-test showed a higher significant mean value of 10%Ch/CP group than 5%Ch/CP group at each week interval. Conclusions: The orthodontic primer modified by nano-chitosan/ calcium phosphate can be considered as an effective method for preventing white spot lesion during orthodontic treatment by promoting release of essential elements required for enamel remineralization.