Maxillary Molar Distalization in Treatment of Angle Class II Malocclusion Growing Patients: Uncontrolled Clinical Trial

Int Orthod. 2020 Mar;18(1):96-104. doi: 10.1016/j.ortho.2019.11.003. Epub 2020 Jan 20.


Objective: This study was conducted to evaluate the clinical effectiveness treatment effects of a simple buccal technique for maxillary molar distalization using direct buccal skeletal anchorage.

Materials and methods: After sample size calculation, fourteen female patients with bilateral Class II molar relationship (age 11-14 years) were selected from the clinic of the Department of Orthodontics, Faculty of Dentistry, Mansoura University, Egypt. After the application of the eligibility criteria, only eleven patients remained to final evaluation. The criteria included: erupted second maxillary molars, mild to moderate maxillary crowding not exceeding 6mm with/without increased overjet and non-extraction treatment in the lower arch. After alignment and levelling, a miniscrew (1. 8mm diameter - 0. 8mm long) was placed buccally between the maxillary second premolar and the first molar in each side. The maxillary molar distalization was done using 250 grams of force produced from NiTi closed coil spring stretched to a buccal miniscrew. Records including cephalometric x-rays and study casts were taken for all patients before and after molar distalization. Statistical evaluation was performed for the data obtained from analysis of cephalometric tracing and cast photocopies.

Results: The maxillary first molars were distalized with a rate of 0. 89±0. 30mm (95% CI 0.76-1.02) (P<0.001) and distalization amount of 4.09±0. 92mm (CI 3.68-4.50) (P<0.001). They were distally tipped by 2.48°±6. 16 (CI -0.26-5.21) (P=0.073) and rotated distopalatally by 11.89°±5.86 with negligible change in their vertical position about 0.11±0.63mm (CI -0.40-0.17) (P=0.411). There was no anchorage loss evident by the distal movement of all the maxillary teeth (P<0.001). Overjet significantly reduced by 0. 86±0. 50 (CI 0.52-1.20) (P=0.004).

Conclusions: Maxillary molar distalization using a closed coil and buccal miniscrew is an effective and non-compliance dependent technique in a relatively short time.

Keywords: Ancrage direct; Direct anchorage; Distalisation molaire; Mini-vis; Miniscrew; Molar Distalization; Orthodontics; Orthodontie.