No abstract

In young adults fixed functional appliances are a treatment alternative to extraction therapy but to a lesser extent to orthognathic surgery. Because of their limited skeletal effects and minor changes in the profile they are indicated only in patients with a moderately severe Class II malocclusion. Pre-treatment proclined mandibular incisors limit the scope of indications for fixed functional appliances, as they can cause an increase in lower incisor proclination. Significant reductions in profile convexity are achievable only by combined orthodontic and surgical treatment of the malocclusion. When performing camouflage orthodontics in conjunction with maxillary premolar extractions in adults, an increase in the nasolabial angle, which is often esthetically undesirable, has to be discussed as a potential side effect and has to be taken into account when considering the different therapeutic approaches.

No abstract

Treatment with a fixed functional appliance in Class II patients effected significant changes in mandibular growth and correction of the distal intermaxillary relationship even after the pubertal growth spurt in adolescents and young adults. While the proportion of the orthopedically-induced skeletal share is subject to substantial inter-individual variability in adolescents, the overall conclusion can be drawn that skeletal effects (= stimulation of mandibular growth) in general clearly lessen with increasing patient age. In young adult patients, the correction of a distal intermaxillary jaw relationship is manifested primarily as a dento-alveolar compensation for the skeletal malocclusion.

Upon assuming the therapeutically-desired position, the condyles were caudally and ventrally displaced from their centric position within the fossa. At the end of treatment, they had returned to their original position. When assessed laterally, statistical analysis revealed no significant differences between the joints on the right and left sides. Neither the anterior nor posterior joint space among all 40 joints exhibited significant changes in width compared to the baseline findings. Visual inspection in the axial, frontal, and sagittal planes revealed changes in the exterior form of 31 of the 40 condyles analyzed. On the whole, while morphologic changes were observed in all three planes, they were most marked in the axial plane. Metric analysis of the 2D-MRIs, on the other hand, revealed no significant changes in width, depth, or height in the plane in question. This is why we reconstructed the condyle structure three-dimensionally on a trial basis. For purposes of analysis, we super imposed the reconstructions of the condyle surfaces at the various control points on each other. By processing the data in this manner, an alternative approach for evaluating morphologic changes was created. CONCLUSIONS AND PROSPECTS: In patients treated with a rigid, fixed functional orthopedic appliance (FMA) for skeletal Class II malocclusion, both joints returned to a physiologic condyle-fossa relationship post-treatment. The improved occlusion was not achieved at the price of unphysiologic repositioning in the temporomandibular joint. Visual inspection suggested that morphologic changes in the condyle may have occurred as treatment progressed, but this was not confirmed by 2D metric analysis. However, by means of 3D-reconstruction of the condylar surfaces and their superposition, detailed visualization of adaptive mechanisms and their non-invasive evaluation in 3D may become feasible in clinical routine.