Treatment effects of distal movement of lower arch with miniscrews in the retromolar area compared with miniscrews in the posterior area of the maxillary.
OBJECTIVE
The aim of this study was to compare the effects of group distal movement of lower teeth obtained with the aid of direct usage of miniscrews in the retromolar area and indirect usage of miniscrews in the posterior area of the maxillary.


METHODS
Nineteen patients with mild-to-moderate class III malocclusion (4 males and 15 females) were divided into 2 groups. Ten patients (2 males and 8 females; mean age, 20.7 ± 2.5 years) in group 1 were treated by miniscrews in the retromolar area. Nine patients (2 males and 7 females; mean age, 21.5 ± 3.7 years) in group 2 were treated by miniscrews in the posterior area of the maxillary. Lateral cephalometric headfilms were taken at the beginning of treatment and after distal movement of mandibular dentition for the evaluation of the treatment changes.


RESULTS
In group 1, the crown and root apex of lower first molars were moved distally by 3.4 mm and 1.2 mm with distal tipping of 8.7 degrees and intruded by 0.7 mm. In group 2, the crown and root apex of lower first molars were moved distally by 3.3 mm (P = 0.8976, P > 0.05) and 0.2 mm (P = 0.0124, P < 0.05) with distal tipping of 10.7 degrees (P = 0.0467, P < 0.05) and extruded by 0.2 mm (P = 0.0124, P < 0.05). Retraction of the mandibular arch lasted 6.31 ± 1.45 months for group 1 and 7.61 ± 1.46 months for group 2.


CONCLUSIONS
Direct usage of miniscrews in the retromolar area took less time and more bodily movement to retract the lower arch without cooperation of the patients and was a better choice for the patients with potential temporomandibular joint disorders problems.
From the *State Key Laboratory of Oral Diseases (Sichuan University), Department of Orthodontics, West China Stomatological Hospital, Sichuan University; and †Chinese Orthodontic Society, Chinese Stomatological Association, Orthodontic Department, West China School of Stomatology, Sichuan University, Chengdu, China.
Cui
C
Ye
Zhao
Z
Zhihe
Qing
Q
Zhao
Jun
J
Ye
D000293:Adolescent; D000328:Adult; D001863:Bone Screws; D002508:Cephalometry; D005260:Female; D006801:Humans; D008297:Male; D008313:Malocclusion, Angle Class III / Q000209:etiology / Q000628:therapy*; D008437:Maxilla; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D011378:Prognathism / Q000150:complications*; D016037:Single-Blind Method; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*; D055815:Young Adult