comparative study between two molar distalization 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 anterior teeth. The aim of this study was to compare the clinical dental effects of these two different molar distalization devices, involving 29 patients having class IImalocclusion with low angle or normal angle. The Intra-oral Bodily Distalizer [I.B.M.D], which is a fixed appliance that consisted oftwopre-activated molar distalization springs bent in TMA wire 0.032 x 0.032 inch and a modified Nance to maintain anchorage, was used in 14 patients. The Acrylic Cervical Occipital Anchorage [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 anterior elastic as well as cervical headgear 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. Measurements were made from the lateral cephalogram tracings before and after molar distalization. The results showed that with I.B.M.D maxillary first molar distalized bodily on an average of 4.5 mm and the mean anchorage loss was 4.75 mm. 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, anchorage loss with A.C.C.O appliance was less being 2.11 mm on an average due to the use of the headgear. In I.B.M.D the distalization spring being composed of square sectioned TMA wire 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 headgear may be effective for orthopedic purpose. Moreover the I.B.M.D. appliance was not patient dependent whereas for A.C.C.O. patient's compliance was found to be a must