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Biomedical subjects

R Noachtar

Publications and source records attributed to R Noachtar.

3 recordsLinked to original sources

Functional appliance therapy with the Bionator.

Since the early 20th century, functional appliance therapy has been a significant part of orthodontic treatment, especially in Europe, where functional appliances have been used to treat many malocclusions, including some skeletal discrepancies. Although the success of functional appliance therapy as reported in numerous short-term studies from 1930 to 1975 led to an euphoric acceptance of this method, the few long-term studies, especially those comparing treated with untreated homogeneous control groups, indicated that the specific skeletal and dentoalveolar effects depended on the individual growth period and pattern of the patient. In this article, a specific functional appliance, the Bionator, is presented. Long-term follow-up studies provide indications for its use. At the present time, functional orthopedic appliance therapy has a more limited but well-defined place in our therapeutic approach. The type and character of the malocclusion determines the indications and contraindications of the functional appliance. Scientific and clinical experience has shown the importance of a differential diagnosis for each patient, which integrates etiology and morphogenesis in the individual treatment objectives for special skeletal, dentoalveolar, and functional regions. Individualization in the construction of the appliance, taking the above-mentioned factors into consideration, is essential for optimal clinical results.

Activator Appliances↗

Age-related differences in mandibular ramus growth: a histologic study.

Histologic reconstructions of remodeling variations of the mandibular ramus are demonstrated. This is significant because morphogenic relationships between the ramus and corpus establish mandibular arch position. Ground and polished microscopic sections were obtained from the ramus of 30 well-preserved human mandibles, dental age 1 to 13 years. The distribution of the various types of endosteal and periosteal bone tissues and resorptive versus depository surfaces was recorded. Fourteen of the 30 specimens and the majority of the mandibles at all ages examined exhibited the classic pattern of deposition and resorption (Type A or classic pattern) described by Enlow. Nine mandibles followed a second variation (Type B or vertical variation) involving a gonial angle alignment change. Seven followed a pattern of deposition and resorption similar to what Björk might have called a forward rotating pattern (Type C or rotation variation). The differences in these patterns are large enough to suggest that a common description of one pattern of remodeling for all mandibles is incomplete. Unfortunately, the process of mandibular growth and remodeling does not appear to correlate well with dental age and the basis for changes in patterns may be more complex than first imagined. If temporal differences exist, they are not related directly to dental development. In theory, the differences in pattern are great enough to influence the outcome of mandibular orthopedic treatment.

Adolescent↗

Cephalometric evaluation of two treatment strategies for deep overbite correction.

This study compared the cephalometric changes achieved using fixed versus removable appliances to correct deep overbite in growing patients. Forty-five patients treated with cervical headgear/tandem mechanics and 50 patients treated with a bionator appliance were compared with 95 control subjects from the Bolton Study. Treatment differences were determined using a cephalometric analysis that isolated vertical changes in overbite as the composite result of 6 variables: maxillary skeletal change, tipping of the upper incisors, bodily movement of the upper incisors, mandibular skeletal change, lower incisor tipping, and bodily movement of the lower incisors. The interaction of treatment type with facial type was also examined. In the headgear/tandem group, overbite was corrected by a combination of intrusion of the upper incisors and increases in mandibular skeletal change. Treatment with the bionator resulted in correction of the overbite by relative intrusion of the upper and lower incisors and increases in mandibular skeletal change. There were no significant interactions with facial type in the headgear group. Gonial angle and lower tipping were influenced by facial type in the bionator group. These results demonstrate that fixed and removable appliances produce both qualitative and quantitative differences in treatment response. Further studies are planned to create a rational decision tree that can be used to aid the clinician in the differential diagnosis and treatment of deep overbite.

Activator Appliances↗