Comparative study between two different molar distalisation appliances

Abstract

Class II malocclusion with moderate space deficiency in the maxillary arch and a relatively well aligned mandibular dental arch can be treated in many ways. One possibility to treat without extraction is to distalize the maxillary first molars to a class I molar relationship in order to gain space in the lateral segments, for retraction of cuspids and anteriorteeth. The aim of this study was to compare the clinical effects of these two different molardistalization devices, envolving 29 patients having class II malocclusion with low angle or normal angle. The I.B.M.D, which is a fixed appliance that consisted of two pre-activated molar distalization springs bent in TMA wire 0.032 x 0.032 inch and a modified Nance tomaintain anchorage, was used in 14 patients. The A.C.C.O appliance being a combination of fixed and removable appliance consisting of an acrylic plate with 2 finger springs and a modified labial section containing groove for the anerior elastic as well as cervical head gear was given in 15 patients. The I.B.M.D and A.C.C.O were used for the mean period of 7.2 months and 11 months respectively. Measurments were made from the lateral cephalogram tracings before and after molar distalization. Our results showed that with. I.B.M.D maxillary first molar distalized bodily on anaverage of 4.5 mm and the anchorage loss was 4.75 mm on an average. Where as with A.C.C.O mean distal movement of the maxillary first molar was 4.38 mm with mesial tip of 3.03 degree. However, the anchorage loss with. A.C.C.O appliance was less being 2.1 mm on an average due to the use of the head gear. In I.B.M.D the distalization spring being composed of TMA wire rectangular in cross section distalized the maxillary first molar bodily without any rotation. While with A.C.C.O appliance tipping was seen. However in the maxilla the use of head gear may be effective for orthoaedic purpose. More over the I.B.M.D. appliance was not patient dependent whereas with A.C.C.O. patient's compiance was found to be a must.