A comparative surface study of 3rd molar enamel from different subjects

Success of orthodontic treatment with fixed appliance relies on the ability to create a strong bond between the brackets and the enamel. Despite advances in dental material bond failure constitutes a major problem in the orthodontics practice. Anecdotal evidence from orthodontist points out that certain patients have a higher bond failure incidence than others. The purpose of this study was to identify surface characteristics of the enamel that may influence bond strength. Two by two millimeter enamel samples were obtained from the buccal aspects of third molars. The sections were then analyzed using X-Ray photoelectron spectroscopy (XPS) before and after 30 seconds etching with 37% phosphoric acid. Statistical significant differences were shown in surface enamel composition prior and after etching. Scanning electron Microscopy (SEM) and Krypton adsorption technique were performed to the etched samples. Enamel specific surface area was determined by applying the BET (Brunnauer, Emmet and Teller) equation to the Krypton adsorption data. A statistical correlation between the grading system utilized here and the specific surface area could not be established. However, a linear regression analysis demonstrated that the ratio between Calcium, Carbonate and phosphate before and after etching may play a role in determining etched enamel specific surface area.; Further studies should focus on establishing systems that would allow predicting bond strength on individual patients. With this information orthodontist would take the adequate steps to prevent bond failure in these patients.