Backgrounds: Both continuous and intermittent loadings are commonly applied in orthodontics.Clinical experiences and some studies believed that longer duration of force produce more effect(tooth movement,suture expansion,bone remodeling)than transient forces applied with the same magnitude.Alternatively,others indicated that interruption or recovery periods of various periods between loadings cause more bone remodeling and less root resorption.Therefore,which force is more favorable for osseointegration and stability of orthodontic mini-implant remains to be elucidated.Thus,the study was designed to evaluate the influence of continuous or intermittent loading on stability of titanium mini-implants.