PROF. DR. PETER SCHOPF Maxilary Orthopedics Director Department of Maxilary Orthopedics, University of Frankfurt Frankfurt, Germany AMOM

The prognosis of the therapy of a Class II-malocclusion with increased overjet depends - more than at many other malocclusions - on the age in which the orthodontic treatment is started. For a successful correction of a retrognatic mandible, it is of essentiel importance, whether growth can be used for the treatment or- not. Therefore, for the choice of the best treatment-time the skeletal age is more important than the chronological age. Whithin the orthodontic diagnostic procedures, the skeletal development is normally determined by the evaluation of an x-ray of the hand and wrist. Since the growth-peak in boys is reached in average 2 years later than in girls, the prerequisites for a successful advancement of the mandible are better and longer existing in males than in females.

Beside the skeletal age, also the vertical structures of the cranium (in the sense of a brachy- as well as dolichifacia growth-pattern) are of prognostic importance. In principle - and independent from the inserted appliance - a brachyfacial growth-pattern is more favorable for the correction of a Class II-malocclusion than a dolichofacial pattern.

For the orthodontic treatment-planning it is furthermore important, which morphological deviations (for example a retrognathic or less growing mandible, a labialinclination of the upper as well as a lingualinclination of the lower anteriors, a maxillary prognathism etc.) are responsible for the Class llor for the increased overjet. Therefore, a cephalometric analysis is essential for the treatment-planning.

For the correction of a mandibular retrognathism a large number of different appliances can be used. In the deciduous as well as in the mixed dentition, in general removable appliances (functional orthodontic appliances, guided plates etc) are used, whereas in the permanent dentition predominantly fixed appliances (with intermaxillary elastics, Herbs-appliances, Jasper-Jumper, Headgear etc.) are used for a mandibular advancement, it this is still possible at that time. When a growth-supported correction of the mandibular position can be expected no longer, a surgical therapy can be discussed as compromisetreatment in the adulthood, with pre-and postsurgical orthodontics treatment.

In the lecture, and overwiew is given over.

-the diagnostic procedures for the differentiation of the increased overjet and their prognostic and therapeutic meanings.

-the determination of the skeletal age on the basis of the hand-x-rays and their influence on planning of the orthodontic therapy and the selection of effective appliances and.

-the appliances and therapeutic procedures for the correction of Class II-malocclusions in different age groups
November 26 1998 AMOM. A. C.

Activator-therapy: Basics, planning and realization.

.In 1935 Andresen and Haupl introduced the activator into orthodontics and established the era of functional orofacial orthopedics with the possibility of a biological,. function-supported correction of maloclusions. Afterwards, this classic treatmen-appliance was modified several times, for example by skeletization or insertion of elastic elements (Bionator [balters], kinetor [Stocktisch], GebiBformer [Bimler], Open activator [Klammt],U-Bügel-Akvitator [Karwetzky], etc. Up to this day, the activator -beside the bionator and the functional regulator, [Fraenkel] - is the most-used functional appliance in Europe.

The activator, like its modifications, uses the possibility to change the position of the teeth by an alteration of the functional pattern of the orofacial musculature, to correct Class II -malocc!usions by a (growth-supported) ventral-displacement of the mandible, to close an open bite by elimination of habits and to correct a deep overbity by use of the vertical growth of the posterior teeth. Furthermore, it is an appliance, which can be -used very well to correct dysfunctions of the orofacial musculature. Therefore, the main field of activator-therapy is the treatmen of Class II, div 1 anomalies, habitual open bites and deep bites in growing patients as well as the normalization of the functional pattern. This appliance allows further a good fitting of occlusion and is also to be used as retention-appliance. On the other hand, the activator is not very effective in the achievement of extensive tooth-movements (space closure, bodily tooth-moverrient, rotation), in treatment of adults, the therapy of Class III-malocclusions, for sagittal expansion, correction of a skeletal open bite, for patients with restricted nasal breathing as well as with incongruous dental arches.

The success of an activator-therapy essentially depends on a correct construction-bite and a correct, therapy-dependent grinding. For both actions, there are approved rules. In comparison to its modifications, the construction of an activator is more simple and the appliance is generally provided with only few elements.

With the activator, the orthodontist has han effective functional appliance to his disposal, which is simple to produce and to handle, has a low repair-susceptibility and a sparing, biological effect without damaging side-eftects,

The lecture presents the mechanism, of action as well as the indication and contraindication of functional appliances, the characteristics of the construction and production of the activator the differences to its modifications, the rules for the construction-bite as well as for the grinding in patients with differente malocclusions and for the handling of this appliance (insertion,controls).
November 29 1998 AMOM A. C