Clinical Evaluation of Maxillary Incisors Intrusion: Mini-Screws Versus Burstone Intrusion Arch

Maxillary incisors intrusion is needed in cases with overeruption of these teeth in deep bite and gummy smile. True intrusion requires precise mechanical planning and clinical supervision. This study compares the mini-screw (MS) and Burstone intrusion arch (BIA) methods clinically and radiographically to assess their effectiveness.

Seventeen patients with deep bite were randomly assigned to two groups: the MS group (eight patients, aged 19.75 ± 2.48) treated with MS, and the BIA group (nine patients, aged 20.67 ± 5.41) treated with the BIA method. Ultra-low-dose CBCT (ULD CBCT) scans were taken at the start (T0), immediately after (T1), and 3 months after (T2) treatment. Intrusion amount, rate, inclination changes, overbite, gingival display, root resorption, and periodontal criteria were assessed at three-time intervals: T0-T1, T1-T2, and T0-T2. Data were analyzed using the independent T-test, with significance at p  < 0.05.

The MS group showed significantly greater intrusion than the BIA group at all three-time intervals (p  < 0.001). The active intrusion rate was also significantly higher in the MS method (p  < 0.001). No significant difference was found between the groups in the decrease of overbite. The BIA group showed some relapse during retention, whereas the MS group did not (p  < 0.001). The MS group also had a significantly greater decrease in gingival display than the BIA group (p  < 0.05).

Both MS and BIA methods were effective for maxillary incisor intrusion. The MS method resulted in more true intrusion and less gingival display. After 3 months of retention, the MS group showed no vertical relapse, while the BIA group had a significant relapse of 0.1 mm (p  < 0.001).