Objectives <p>The aim of this study is to compare the biomechanical effects of maxillary first molar intrusion using the fixed appliance, microimplant, and clear aligner with or without 3D printed personalized device, and to demonstrate the effect of this device through a relevant clinical case.</p> Methods <p>A clinical patient with an overerupted maxillary molar was selected to construct a patient-oriented three-dimensional model of the four intrusion patterns. The initial displacement of the teeth and the stress distribution of the PDL were compared. The 3D printed personalized device was used in this case, and the data of the case was collected to assess the therapeutic effect.</p> Results <p>The side effects of target tooth tilt and adjacent tooth displacement were obvious in fixed appliance and clear aligner, while the side effects were smaller in 3D printed personalized device, and the intrusion efficiency is slightly higher than that of microimplant. In clinical practice of 3D printed personalized device, a favorable intrusion effect was achieved.</p> Conclusions <p>The 3D printed personalized device had relatively high intrusion efficiency and stress relaxation on the target tooth and reduced the displacement and stress concentration on the anchorage teeth to a certain extent.</p> Clinical relevance <p>In clinical practice, clear aligner with 3D printed personalized device has a good therapeutic effect on molar intrusion.</p>