MAXILLARY PROTRACTION - TREATMENT AND POSTTREATMENT EFFECTS

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.