Comparison of the effects of class II activatör combined with vertical chin - cap to those with posterior high pull headgear on skeletal and dentoalveolar structures

This study was performed to compare the effects of combined use of activator and vertical chin-cap in the cases who have increased vertical facial height and skeletal class II, division 1 malocclusion; and the combined use of activator and posterior high pull headgear which has been used commonly in such cases, on skeletal and dentoalveolar structures. Research material consisted of lateral cephalograms and hand-wrist radiographs taken at the beginning and at the end of the study from 25 individuals who have increased vertical facial height and skeletal and dental class II, division 1 malocclusions. The average chronological age at the beginning of the study was 12 years 4 months for the first treatment group( activator+high pull headgear), 12 years 2 months for the second treatment group (activator+vertical chin cap). Activator and high pull(occipital) headgear was applied to 12 individuals which consisted of 6 girls and 6 boys in the first treatment group, activator and vertical chin cap was applied to 13 individuals which consisted of 8 girls and 5 boys in the second treatment group. First treatment group was selected from the archives of the department of orthodontics. The members of the second treatment group were carefully matched by skeletal age, vertical and antero-posterior skeletal characterics to correspond to the subjects used in the first treatment group. The treatment time for the first group was between 7 and 26 months and for the second group between 3 and 9 months. Fifty-eight different parameters were evaluated in the lateral cephalograms using not only routine measurements but also Bjork's total, maxillary and mandibular local superimpositions as well. The initial and posttreatment records of both groups have been statistically analysed with "paired-t" test within the group and analysis of variance (ANOVA) between the groups.135 The findings; * In the first treatment group(activator+occipital headgear) posterior rotation was seen in the maxilla during the period of average 12.33 months treatment and the difference between the groups was statistically significant. In the second treatment group(activator+vertical chin-cap) anterior rotation tendency was seen during the period of average 5.23 months treatment. * While anterior rotation in the mandible was not found statistically significant in the first treatment group, it was found significant in the second treatment group but the difference between groups was not statistically important. * The use of activator+vertical chin-cap was found to be a more effective approach to prevent the increase in anterior facial height and downward movement of the chin. * There was not significant difference between the treatment groups according to the amount of improvement between the sagital relationship of the jaws. * There was more significant increase in mandibular length (Co-Pg) in the first treatment group than the second one. * By the effect of using vertical chin-cap there was found to be more significant protrusion in mandibular incisors.