More time is often needed for adult orthodontic patients compared with juvenile counterparts due to lower tissue vitality. In some cases, the prolonged orthodontic treatment may cause a series of problems, such as enamel demineralization, dental caries, periodontitis and root resorption. Therefore, we aimed to accelerate tooth movement to avoid various adverse reactions by 3D-printing assisted micro-osteoperforations (MOPs) in difficult orthodontics cases.Twenty-eight adult patients (28.3 ± 3.4 years) with slow tooth movement after extraction of bilateral maxillary first premolars were included. The scheme of 3D-printing assisted MOPs was designed to perform bone punctures in the mesial and distal sides of canines.The average speed of the retraction of canines was 1.02 ± 0.41 mm per month after MOPs and significantly faster than that before the MOPs, 0.34 ± 0.16 mm per month (P < 0.05). Moreover, the evaluation of side effects including root resorption, periodontal damage did not reach statistical difference and pain level was acceptable generally.MOPs assisted by 3D-printing could significantly accelerate tooth movement while achieving greater precision, without notably increasing side effects.ChiCTR2100044685, date of registration: 25/03/2021.