Morphogenetic response to activator treatment

Differential treatment planning for mandibular prognathism

The treatment records of thirty-eight cases of mandibular prognathism treated by orthodontics means only (ORTHO) were evaluated. The pretreatment records of twenty cases of mandibular subapical esteotomy (SUB) and twenty cases of mandibular setback (SET) were evaluated for comparison and contrast with the pretreatment ORTHO records and with each other. Dental, skeletal, and soft-tissue parameters in the vertical and horizontal planes of space were recorded. Statistical analysis of means of parameters of the pretreatment records provided documentation of the discriminant variables in each of the following paired groups: ORTHO-SUB, ORTHO-SET, and SUB-SET. Analysis of the data as indicated above led to the following conclusions: 1. Three discriminant groups of mandibular prognathism of various degrees of severity were discernible when comparisons of treatment categories simulating clinical decisions were made. The ORTHO group was distinguished from the SUB group in the horizontal plane and, more strongly, in the vertical plane. The ORTHO group was distinguished from the SET group in the vertical plane and, more strongly, in the horizontal plane. The SUB group was distinguished from the SET group in the horizontal plane. 2. The physiologic developmental status of the patient should be carefully evaluated. 3. Anteroposterior dysplasias should be assessed relative to the cant of the mandibular plane. True denture base discrepancies can be noted relative to the occlusal plane. 4. Documentation of vertical dysplasias should include measurements of craniofacial divergence (SN-MP, FH-MP, and OP-MP). 5. In assessing the profile evaluation of the patient with mandibular prognathism, particular attention should be focused on facial contour angle (FCA), nasolabial angle (NLA), and relative lower lip protrusion (LLP). 6. Any numerical values obtained in the evaluation of the dental, skeletal, or soft-tissue characteristics of mandibular prognathism should be considered only as descriptive, diagnostic guides and not as components of a diagnostic formula.

Vertical control: a multifactorial problem and its clinical implications

In this article we have tried to analyze the importance of vertical control in orthodontic cases, as well as the factors affecting it. From the cases presented, it can be assumed that: 1. In vertically growing or nongrowing persons (high-angle cases), the application of proper directional forces becomes extremely critical because a clockwise rotation of the mandible can occur very promptly and is very undesirable. 2. In cases with favorable growth potential, the results may be acceptable, even if the forces applied during treatment are not absolutely controlled; in other words, Mother Nature may often compensate for inappropriate or miscalculated treatment procedures.

Late results of activator-treatment: a cephalometric study

The purpose of this study was to analyse cephalometrically the long-term effect of Activator treatment on the dentofacial skeleton in 50 consecutively treated cases of postnormal and prenormal occlusion. Comparisons of dentofacial form between successful and unsuccessful cases were performed. The results of the study showed that the sagittal relationship between the jaws became normal in postnormal and prenormal cases during Activator treatment. The effect was achieved mainly by reciprocal dentoalveolar changes of the maxilla and mandible supported by a retardation of the forward growth of the maxilla in Class II cases and a stimulation of the forward growth of the maxilla in Class III cases. The normal downward-forward growth of the mandible appeared unaffected. The effect of Activator treatment on the vertical growth of the jaws was a significant increase in lower face height (bite-raising). No tendency to induce a harmful posterior growth rotation of the mandible was noted. Before treatment there was no highly significant difference in the morphology of the dentofacial skeleton between successfully and unsuccessfully treated Activator cases, except for the basal relationship between the jaws (ss-n-sm) which was larger in the successful cases. It would rather appear that good cooperation, high growth intensity and a favourable growth pattern of the patient together with a well constructed appliance is of decisive importance for a successful result of treatment.

The class II malocclusion: differential diagnosis and clinical application of activators, extraoral traction, and fixed appliances

The importance of an exact differential diagnosis of the Class II malocclusion and its indications for treatment with activators, extraoral forces, and fixed appliances has been shown. Four schematized malocclusions with their cephalometric characteristics and their individualized orthopedic therapeutics have been presented. Special attention has been given to the subsequent fixed mechanotherapy showing the limited need for fixed appliances. This approach is attractive, for it reduces considerably the stress imposed on the patient and the orthodontist, it bypasses the iatrogenic hazards entailed in extensive and prolonged mechanotherapy, and it consistently increases chances for long-term stability.

A systematic modification of edgewise therapy

This article describes a highly systematic modifcation of the edgewise technique that incorporates the principle of light continuous force application. It is a re-evaluation of our earlier article in view of the experience gained in applying this treatment approach in a teaching clinic. The classification of cases according to retraction requirements, the appliance designs, and the use of four basic phases of treatment remains largely the same as previously described. Some of the variations and modifications that have been necessary because of new information and pedogogical considerations are discussed. The treatment of typical orthodontic problems with differing retraction requirements is illustrated.