Comparison of dentofacial effects of pendulum- K loop appliance and cervical headgear in molar distalization

ABSTRACT The aim of this study was to compare the dentoalveoler effects of "Pendulum- K Loop" appliance combination and Cervical Headgear. The study group consisted of 30 patients who had dental Class II malocclusion, without transversal deficiency and GoGn-SN angle within normal limits. Fifteen of the subjects used Pendulum-K loop appliance and the other 15 patients used Cervical Headgear for a period of 12 ± 2.93 weeks. At the beginning of the treatment; the mean age of the Pendulum-K loop group was 14.97 ± 3.36 years, and the mean age of Cervical Headgear group was 14.22 ± 2.93 years. Pendulum-K loop and Cervical Headgear groups were matched according to their GoGn-SN angles and the treatment period. Pre-treatment and post- treatment lateral cephalometric, panoramic radiographs and photocopies of models were obtained. Angular and linear 25 parameters were selected and "paired t test" and "student t test" were performed to evaluate the differences between the two groups. Also "Spearman" correlation test was used to evaluate the corelations between upper molar distalization and dentoskeletal parameters which changed significantly during treatment. The amount of distalization achieved with Pendulum- K loop and Cervical Headgear was 4.53 ± 1.46 mm, 2.23 ± 1.68 mm respectively in 12 ± 2.93 weeks. The amount of distal tipping was 5.13° ± 4.90° for the Pendulum-K loop group and the amount of mesial tipping was 0.80° ± 2.27° for the Cervical Headgear group. Maxillary first molar intrusion was 0.90 ± 1.04 mm for the Pendulum-K loop group and 0.20± 1.48 mm for the Cervical Headgear group. Furthermore, mesiobuccal rotation of the maxillary molars achieved in both groups. In the Pendulum-K loop group; the distance between mesiobuccal cusps of upper molars increased, however in the Cervical Headgear group, the distance between both mesiobuccal and distopalatinal cusps was increased. vııIn Pendulum- K loop group, maxillary first and second premolars, moved mesially 0.23 ±1.86 mm and 0.27 ±1.62 mm respectively. Maxillary first premolars tipped 1.67°± 3.44° and maxillary second premolars tipped 2.20° ±2.51° during mesialization. In the Cervical Headgear group maxillary first and second premolars, moved and tipped distally. The amount of distal movement and distal tipping was 0.23 ±1.86 mm and 1.67°±3.44° respectively for the first premolars and 0.27±1.62 mm with 2.20c± 2.51° respectively for the second premolars. The mesialization of anchorage teeth in Pendulum-K loop group was found statistically insignificant, but in the Cervical Headgear group the amount of distalization of these teeth was found to be statistically significant. In the Pendulum-K loop group, labial protrusion and tipping of maxillary incisors was found to be statistically insignificant. In the Cervical Headgear group, 1.09° of palatoversion and 1.57 mm of retrusion of maxillary incisors was found to be statistically significant. In the Pendulum-K loop group, the negative corelation was found between the maxillary molar distalization and the distance between the mesiobuccal cusps of molar teeth. The maxillary molar distalization caused an increase at the distance between the mesiobuccal cusps of molar teeth. In the Cervical Headgear group, positive corelation was found between maxillary molar distalization and maxillary first and second premolar distalization. Key Words: Molar distalization, class II malocclusion, patient cooperation. Vlll