Orthodontics Teaching Unit, Department of Stomatology, University of Valencia, Gascó Oliag 1, 46010, Valencia, Spain.
In private practice, Vitoria, Spain.
Prog Orthod. 2020 Sep 7;21(1):34. doi: 10.1186/s40510-020-00336-2.
Miniscrews are effective devices for performing upper incisor intrusion. Different mechanics can be applied depending on the treatment objectives. This study aimed to evaluate the efficacy of one or two anterior miniscrews for upper incisor correction in cases of overbite and angulation in adult patients.
Forty-four adults with deep overbite were divided into two groups: group 1 was treated with one miniscrew between upper central incisors and group 2 with two miniscrews between upper lateral incisors and canines. Incisor intrusion and length were measured from lateral cephalograms before treatment, after treatment and at least 12 months into retention (T0, T1 and T2). Forces were applied (90 g) from the miniscrews to the archwire using elastomeric chains. ANOVA analysis was used to determine whether differences between evaluation times were statistically significant.
Mean root resorption was 2.15 ± 0.85 mm, which ceased after active treatment. Overbite mean correction was - 3.23 ± 1.73 mm with no statistically significant relapse. Overbite correction and incisor intrusion were significantly greater in group 2 (- 3.80 ± 1.43 versus - 2.75 ± 1.63 for OB and 8.19 ± 3.66 versus 5.69 ± 2.66 for intrusion). Resorption and overbite correction were positively related. No counterclockwise rotation of the mandibular plane was observed.
Overbite correction can be performed by means of upper incisor intrusion without rotation of the mandibular plane. Correction of upper incisor intrusion and overbite is greater in patients treated with two miniscrews. The increase in upper incisor buccal angulation is greater with one miniscrew. Root resorption is positively related to the extent of intrusion. Stability is satisfactory regardless of whether one or two miniscrews are used.
微型种植钉是实现上颌切牙内收的有效装置。根据治疗目标的不同，可以采用不同的力学原理。本研究旨在评估在上颌前突和角度患者中，使用一颗或两颗前微型种植钉对上颌切牙进行矫正的效果。
44 名深覆患者分为两组：组 1 使用上颌中切牙之间的一颗微型种植钉，组 2 使用上颌侧切牙和尖牙之间的两颗微型种植钉。在治疗前（T0）、治疗后（T1）和保持至少 12 个月（T2）时，从侧位头颅侧位片上测量切牙内收和长度。使用弹性链将 90g 的力从微型种植钉传递到弓丝上。采用方差分析（ANOVA）来确定评价时间之间的差异是否具有统计学意义。
平均根吸收为 2.15 ± 0.85mm，在主动治疗后停止。平均深覆治疗后矫正值为-3.23 ± 1.73mm，无明显复发。组 2 的深覆治疗后矫正值和切牙内收量均显著大于组 1（OB 分别为-3.80 ± 1.43mm 和 5.69 ± 2.66mm），而组 2 的切牙内收量也显著大于组 1（8.19 ± 3.66mm）。根吸收与深覆矫正呈正相关。未观察到下颌平面逆时针旋转。
在上颌切牙内收的同时，不旋转下颌平面也可实现深覆矫正。使用两颗微型种植钉矫正上颌切牙内收和深覆的效果更好。使用一颗微型种植钉时，上颌切牙颊侧倾斜角的增加更大。根吸收与内收量呈正相关。无论使用一颗还是两颗微型种植钉，稳定性均令人满意。
