Article information
Year 2021 Volume 71 Issue 1 Page 44-52
Title:
Orthodontic Extraction of Impacted Mandibular Third Molar Using the Minimally Invasive Bracket System
Keyword(s):
Dental anchorage, Orthodontic extraction, Third molar, Uprighting
Abstract:
The purpose of this study was to introduce the application of an orthodontic extraction (OE) with a reinforced dental device, called “minimally invasive bracket (MIB)”, to an upright impacted mandibular third molar (MI8) before extraction. The performance of the MIB for OE of an MI8 was investigated. Twenty-four MI8s, planned for OE, were divided into two groups. In the MIB group (n= 12), the MI8s were uprighted with anchorage reinforcement of posterior teeth provided by the MIB. In the control group (n= 12), the MI8s were uprighted without any anchorage reinforcement. All MI8s were removed by simple extraction after the uprighting process. Lateral cephalograms and panoramic radiographs were taken at the beginning (T0) and by the end (T1) of the uprighting process. Using T0 and T1 radiographs, altered movement and angulation of the MI8 (moving unit) and adjacent second molars (anchorage unit) were monitored and compared between the two groups. For the moving unit, the amount and rate of MI8 distalization between the MIB (1.8±1.0 mm, 0.9±0.5 mm/month) and control (1.3±0.7 mm, 0.6±0.3 mm/ month) groups were significantly different (p=0.117, 0.041). For the anchorage unit, the amount and rate of second molar mesial tipping between the MIB (1.8±0.9º, 0.8±0.2º/month) and control (4.2±2.5º, 1.8±0.9º/month) groups were significantly different (p=0.008, 0.004). The amount and rate of second molar mesialization between the MIB (0.6±0.3 mm, 0.3±0.1 mm/month) and control (2.1±0.9 mm, 1.0±0.2 mm/month) groups were significantly different (p=0.000, 0.000). The amount and rate of second molar intrusion between the MIB (0.7±0.3 mm, 0.3±0.2 mm/month) and control (1.8±0.9 mm, 0.8±0.3 mm/month) groups were significantly different (p=0.002, 0.000). OE with the MIB efficiently uprights the MI8s and reinforces dental anchorage, thus avoiding undesirable dental movement.