Molar distalization with pendulum and distal screw appliances
Caprioglio A, Cafagna A, Fontana M, Cozzani M. Comparative evaluation of molar distalization therapy using pendulum and distal screw appliances. Korean J Orthod 2015;45:171-9
Maxillary molar distalization may be indicated in the treatment of malocclusions with a Class II molar relationship. Common side effects of conventional molar distalization appliances are distal tipping and rotation of the distalized molars, as well as anchorage loss demonstrated as mesial movement of premolars and proclination of incisors. The use of mini-implants for direct anchorage helps to control some of these adverse effects. The authors of this study used lateral cephalograms before and after distalization to compare the skeletal and dentoalveolar changes produced by the pendulum appliance (PA) and the implant-supported distal screw appliance (DS) in patients with Class II malocclusion. Twenty-four patients treated with the PA and 19 with the DS were selected retrospectively. The amounts of molar distalization achieved in the PA and DS groups were comparable after distalization (4.7 and 4.2 mm, respectively). However, the PA group had more side effects with greater distal tipping and premolar anchorage loss and more incisor proclination. In the implant-supported DS group, the premolars moved distally, and changes in incisor position were insignificant. No significant sagittal or vertical skeletal changes were seen in either group. The mean distalizing times were 7 months for the PA group and 9 months for the DS group. These results indicate that maxillary molar distalization with direct anchorage and a rigid appliance is effective in distalizing molars and produces less distal tipping and anchorage loss, while remaining independent of patient compliance. Limitations of this study include the retrospective selection of patients from an existing sample and the inability to assess molar rotation because of the use of only cephalometric radiographs without the dental casts.
Reviewed by Sarah Habib
Radicular and coronal arch perimeter effects of bracket prescription
Pontes LF, Cecim RL, Machado SM, Normando D. Tooth angulation and dental arch perimeter—the effect of orthodontic bracket prescription. Eur J Orthod 2015:37:435-9
Variations in crown angulations of bracket prescriptions have been shown to cause changes in dental arch morphology, particularly the dental arch perimeter. The purpose of this study was to evaluate the effects of maxillary incisor and canine angulations caused by standard edgewise orthodontic brackets and brackets with 4 straight-wire prescriptions (Andrews, Capelozza, Roth, and MBT) on dental arch perimeter. Cone-beam computerized tomography scans of 31 (15 men, 16 women) nonsyndromic patients with complete dentitions and no restorations or prior orthodontic treatment, at a mean age of 23.4 years, were selected from a database of routine examinations of a clinical radiology center. A virtual dental model was constructed using the average dental dimensions of this sample to represent the real anterior dentition. These dimensions included the width of the tooth crown at its incisal, middle, and cervical thirds, and the clinical crown height. The largest linear distances of tooth crown (anterior arch) perimeter and root (radicular) distance were obtained for each bracket prescription using the AUTOCAD software tools. Increases in tooth angulation were found to produce a mild increase in the perimeter of the anterior arch at the crown level and a more significant increase in the radicular area. The consequences of the bracket prescription on the proximity of neighboring roots require further exploration, since it could affect the relationships with surrounding structures and influence the overall orthodontic treatment plan.
Reviewed by Michelle Kornbluth