Poor elasticity, if the metal orthodontic device may also cause mucosal ulcers, invisible aligners using elastic diaphragms will not produce mucosal irritation, orthodontic strength is also relatively soft; 3, convenience, fixed aligners can not be removed at will, during the orthodontic period will bring embarrassment, worry, invisible aligners can be freely removed, wearing convenient does not affect normal life work, learning and social; 4, the maintenance of oral hygiene; 4, oral hygiene maintenance, fixed orthodontic appliance glued to the tooth surface, can not take it off, oral hygiene maintenance is difficult, easy to lead to demineralization of the tooth surface, and gingival inflammation and other complications, invisible orthodontic appliance is simple, in the brush teeth when eating can be taken down to maintain oral hygiene is very convenient; 5, the prediction of the effect, fixed orthodontic appliance is difficult to do for each patient to carry out three-dimensional simulation The effect of prediction, invisible aligners into the computer-aided design, you can foresee each stage of tooth alignment and movement and the effect of correction, fixed aligners although they can not be taken to wear, but has its advantages, that is, the force of correction lasting high correction effectiveness, the ability to make multiple teeth move as a whole, the ability to accurately control the direction of movement of orthodontic teeth, the effect of correction by the patient is small, and fixed aligners The range of application is greater than that of invisible aligners, while invisible orthodontics should still be strictly controlled for clinical indications.