Changes in dental arch dimensions by use of an orthopedic cervical headgear in Class II correction.

Orthopedic cervical headgears are commonly used in Finland for early treatment of the Class II malocclusion, but there is a lack of follow-up studies on the effect of this treatment. We have evaluated the effects of the cervical headgear therapy with an expanded inner bow to treat Class II malocclusion and dental arches. Forty children, 20 boys and 20 girls, with Class II, Division 1 malocclusion, were treated with the orthopedic cervical headgear. No other appliances were used. The mean age of the subjects in the beginning of the treatment was 9.3 +/- 1.3 years (range 6.6 to 12.4 years). The mean treatment time was 1.8 +/- 0.6 years (range 0.8 to 3.1 years). The cervical headgear was used with a 10 mm expanded inner bow and a 15 degrees upward bend of the long outer bow, 12 to 14 hours a day with a force of 500 gm per side. Class I relationships were achieved in all subjects. At the same time, the maxillary and mandibular dental arches were widened. The annual increment in the intercanine and intermolar distances was significantly greater than in healthy control subjects (literature data), except for the mandibular intercanine distance in boys. The maxillary arch lengths were also significantly increased; there were no consistent changes of the mandibular arch lengths. Class II malocclusion may be treated with the orthopedic cervical headgear. The treatment results in increased growth of the dental arch widths by expansion of the inner bow of the headgear. The widening of the maxilla is followed by spontaneous widening of the mandible.