Rw. Gallagher et al., MAXILLARY PROTRACTION - TREATMENT AND POSTTREATMENT EFFECTS, American journal of orthodontics and dentofacial orthopedics, 113(6), 1998, pp. 612-619
This study evaluated the treatment response and posttreatment follow-u
p of children with Class III malocclusions treated with palatal expans
ion and reverse-pull face mask to the maxilla. The sample included 22
white children, 9 boys and 13 girls. Treatment began at a mean age of
9.8 years (range 5.6 to 13.3 years) and lasted 0.7 years (range 0.3 to
1.3 years). With a protraction force of 600 to 800 gm, the patients w
ere treated until a 2 mm positive overjet had been attained. Radiograp
hs were taken before treatment (T1), immediately after face mask treat
ment (T2), and 1.4 years after treatment (T3). An age and sex matched
sample of untreated white schoolchildren served as normal controls. Th
e results showed that the anterior maxilla was protracted forward 1.6
mm per year more than normal. The posterior maxilla dropped inferiorly
more than the anterior maxilla. The mandible was rotated downward and
backward, while the lower incisors were uprighted. The effects on the
mandible were attributed to a significant chincup effect exerted by t
he face mask. After treatment, the maxilla relapsed relatively backwar
d in the anterior and upward in the posterior, negating some of the tr
eatment results. The mandible resumed a normal growth direction, and t
he lower incisors flared more than normal.