Composition characteristics of ceramic brackets

It is mainly polycrystalline or single crystal alumina. The main difference between the two materials is their light transmittance. Single crystal alumina has higher transparency, while polycrystalline alumina is usually white (tooth-colored). Single crystal alumina is sometimes called single crystal sapphire. The reason why alumina is used to make brackets is that it is strong, beautiful, and not easy to color or release odor.

There are two types of bottom surfaces for ceramic brackets. One kind has a groove-shaped bottom surface, which provides a mechanical lock for the adhesive. The bottom surface of this kind of bracket is flat, the surface is coated with silane, and there are small undercuts to increase mechanical support. Compared with other structures, the bottom surface of the bracket, which has both micro-mechanical bonding and chemical bonding, reduces its mechanical retention force. The other has a smooth bottom surface, and the chemical coating on its surface increases the bonding strength. Due to the presence of inert substances in the alumina ceramic bracket, the silane coupling group acts as an intermediate medium to connect the resin adhesive and the surface of the bracket. According to reports, the design of the bottom surface of this bracket can achieve a greater chemical bonding force than the mechanical retention force. In order to avoid potential damage to tooth enamel when removing the brackets, a polycarbonate film can be coated on the bottom surface of the brackets. In this way, the enamel surface is not directly combined with the adhesive, but in contact with the film, which makes it easier to remove the brackets, which reduces the damage to the enamel.