[The mesialization of molars of the lower jaw after performance surgical manipulation with using miniscrew anchorage approach].

Unlabelled: Process of the mesialization of molars in the lower jaw is long-time, moreover the molars are not frequently bodily translation. Conduction of the corticotomy reduce to regional acceleration phenomen that permit to accelerate the tooth movement avoiding negative inclination.

Purpose: To improve the effectiveness of the treatment using piezocorticotomy and miniscrew anchorage approach in cases of third and second molar mesialization when first molar is missing.

Material And Methods: 24 patients (10 men/14 women) aged 25-40 years with a fixed vestibular braces and the absence of molars on the lower jaw. Cone-beam computed tomography was performed before and after orthodontic treatment, as well as immediately after the piezokortikotomy (79 Cone-beam computed tomography). Miniscrews was placed in the area between roots of the first and second premolars (27 miniscrews) and surgical manipulations was performed using device VarioSurg (NSK, Japan). Depending on width of the alveolar ridge piezocorticotomy was performed (16 piezocorticotomies) or splitting using piezosurgery approach (11 splitting).

Results: Mesialization speed of molars in patients with support of piezocorticotomy is equal to 1.1±0.1 mm/mo that is higher than in patients without surgery only with miniscrew approach (0.33±0.006 mm/mo Roberts et al, 1996). Mesialization speed of molars in patients with support of splitting is equal to 1.6±0.15 mm/mo. However, we observed that after corticotomies surgery, the speed was increased only within the first 4.5 months, after splitting, the speed was increased only withing 2.5 months, after that period the speed gradually decreases. Bone density after surgery decreased, but at the end of treatment gradually restored.

Conclusion: Piezo surgery with corticotomies is an effective method to accelerate the mesialization of molars in the lower jaw, that conduce to reduction duration the treatement and to allow to almost bodily translation of the molars.