To evaluate dento-skeletal changes following conventional anchorage molar distalization therapy in adult patients.
Thirty-three adult patients (25 females, mean age 23 years 1 month; and 8 males, mean age 28 years 3 months) were recruited from 4 Board Certified specialists (multicentre study). All subjects underwent molar distalization therapy using intraoral non-compliance distalizing appliances (Pendulum, Distal Jet, Fast Back: n=14; compressed nickel-titanium coil-spring: n=11; Loca-system wires: n=8). The average amount of class II molar relationship was 4.8 ± 1.2 mm, and the mean amount of overjet was 5.9 ± 1.7 mm at the beginning of treatment. Cephalometric headfilms were available for all subjects before (T1) and at the end of comprehensive orthodontic treatment (T2). The initial and final measurements and treatment changes were compared by means of a paired t-test.
Mean total treatment time was 3 years 2 months. Maxillary first molar distalized 2.9 mm contributing 59% to class II molar correction, whereas mandibular first molar showed a concomitant mesial movement of 2.1 mm.
Maxillary incisors retroclined an average of 5.8°, lower incisors proclined 5.1° and occlusal plane rotated down and backward 1.9°. Clockwise rotation of the mandible (1.9°) and increase in lower facial height (2.8 mm) were also observed.
Maxillary molar distalization therapy can be performed in adult patients, since maxillary molars can be found in a more distal position at the end of comprehensive treatment by the maxillary superimposition. However, these findings should be carefully evaluated; in fact, molar distalization contributed only 59% to the Class II molar correction, while 41% was due to the concomitant mesial movement of the mandibular molars.
Moreover, overjet was mostly corrected by dentoalveolar changes at maxillary and mandibular incisors, and a moderate increase in vertical facial dimension, as well as a slight clockwise rotation of the mandible, should be considered using this procedure.
M. Fontana, M. Cozzani, A. Caprioglio
Università Insubria – Varese, Italy
European Journal of Clinical Orthodontics (EJCO)