Force delivery of Ni-Ti coil springs.

Sentalloy springs (GAC, Central Islip, N.Y.) of the open and closed type were investigated with a special designed device. The closed coil springs were subjected to a tensile and the open coil springs to a compression test. After a first measurement, the springs were activated for a period of 4 weeks and then reinvestigated with the same procedure. It could be shown distinctly that, with the different coil springs, the force delivery given by the producer could be achieved only within certain limits. To remain in the martensitic plateau, changed activation ranges, and for the Sentalloy coil springs white and red of the open and closed type, also changed force deliveries had to be taken into account. There was a distinct decrease in force delivery between the first and second measurement. After considering the loading curves of all the Sentalloy coil springs and choosing the right activation range respective to the force delivery, it was found that the coil springs deliver a superior clinical behavior and open new treatment possibilities.

[Corrective movement of a palatal impacted canine tooth: methodology and outcome of a combined oral surgery/orthodontic procedure]. / Zur Einreihung des palatinal impaktierten Eckzahnes: Methodik und Ergebnisse eines kombinierten kieferchirurgischen/kieferorthopädischen Vorgehens.

In 24 patients, 31 palatal impacted maxillary canines were brought in position using the same surgical and orthodontic concept. After temporal surgical exposure a little silver chain was attached at the crown of the canine, the mucoperiostal flap was repositioned, and the canine was moved into its position by innovative orthodontic treatment means. The combined method is described intensively. With respect to the applied technique the results indicate that according to the criteria of periodontal status, vitality, bone support, root resorption and occlusion no differences exist to free erupted canines despite a mean orthodontic correction of 36.7 degrees.

[Headgear-free molar distalization]. / Die headgearlose Molarendistalisation.

The difficulty in treating dentoalveolar class II disharmonies is briefly outlined. An innovative treatment method is presented which makes possible a distalization without the use of headgear. In the treatment method bands are cemented on the first molars, next impressions are made of the upper and lower dental arch, and then the impressions are poured with plaster. Following this the models are mounted in centric relationship in an articulator and the bite is opened 2 mm to 3 mm, so that the molars can be moved without making occlusal contact. The apparatus, an acrylic splint, is constructed in such a fashion as to cover the palatal surfaces from 2nd premolar to 2nd premolar. In addition, the premolars are also covered occlusally and buccally and the canine tips and the incisal edges are covered labially. A headgear tube is attached at the buccal surface in the premolar region of the acrylic splint. This acrylic splint, which is itself retentive, is cemented using glass ionomer cement. Combining this apparatus with a modified Nance Button makes it possible to establish an anchoring segment which is able to retain its position in the face of molar distalization. Molar distalization is then performed using a 0.032 inch stainless steel wire, which is placed between the headgear tube of the acrylic splint and the headgear tube of the band of the first molar. Highly elastic nickel-titanium open coil springs are used as the force elements.

[Measuring equipment for determining the elastic behavior of various wire configurations of orthodontic metal alloys]. / Messapparaturen zur Bestimmung des elastischen Verhaltens verschiedener Drahtkonfigurationen orthodontischer Metallegierungen.

The paper describes devices which enable the orthodontist (oral surgeon) to accurately determine the forces produced by orthodontic wire or spring constructions. An apparatus was developed with which the force applied by bent wires--various materials and bending methods--could be assessed. This device uses strain gauges arranged in the form of a semi-bridge as sensors. Measurements showed that the smallest application of force was achieved with braided stainless steel wires. With respect to the consistency of the force applied, nickel-titanium alloys (so-called Japanese Ni-Ti) proved the best material for wires bent with electric current. A second device was constructed which permits the evaluation of the compression and tensile forces applied by springs as a function of movement. Here, too, strain gauges were used as sensors. The freely adjustable range can be determined using a digital distance meter with an accuracy of 0.1 mm. Measurement of the elastic behaviour of these spring configurations revealed that in comparison with stainless steel, nickel-titanium alloys were much more consistent in terms of force applied. Using these devices, the orthodontist can fit calibrated configurations, thus avoiding unsuitable forces.

[The biomechanics of space closure and its dependence on the periodontal attachment]. / Die Biomechanik des Lückenschlusses und ihre Abhängigkeit vom parodontalen Attachment.

The biomechanics of space closure in adult patients with loss of periodontal attachment is described. In order to achieve an even force distribution in the periodontium, force was reduced and the moment to force relationship was increased. beta-TMA-T Loops of 0.016 inch x 0.022 inch and 0.017 inch x 0.025 inch cross sections were investigated. With an automatic testing device force and moment values were determined.

[Long-lasting treatment technic in the periodontally reduced dentition]. / Die festsitzende Behandlungstechnik im parodontal reduzierten Gebiss.

A precondition for satisfactory (long-lasting) prosthetic results is a good occlusion. This can sometimes only be achieved with the aid of orthodontics. This article concludes that orthodontics can be carried out in patients with reduced periodontal support provided thorough periodontal treatment is carried out initially and treatment goals and biomechanics are carefully considered.

[Comparative studies of fiberglass and metal brackets]. / Vergleichende Untersuchungen von Fiberglas- und Metallbrackets.

The demand by patients considered for better esthetics during treatment should be seriously considered. With the introduction of fiberglass brackets one has tried to solve that problem. The purpose of this investigation was: 1. a microscopic examination of the slots of these fiberglass brackets after various periods of wearing; 2. an in vitro investigation of the adhesion of the fiberglass brackets in comparison to metal brackets; The following results were obtained: 1. There are remarkable differences in the slot dimensions between new fiberglass brackets and those which have been in the mouth for varying periods of time. 2. Ligating wires into fiberglass brackets may be difficult because of wing fractures. 3. There are significant differences regarding the adhesion of fiberglass brackets compared with metal brackets. Results of tests carried out under defined conditions (bonding, storage, time-factor) concluded that metal brackets behaved much more favourably; the adhesion of metal brackets was nearly ten times greater than that for fiberglass brackets.

[The use of modern ceramics for inlays and onlays]. / Die Anwendung moderner keramischer Materialien in der Inlay-Onlay-Technik.

If ceramic inlays and onlays are considered in restorative work, some operations which, more than in other areas of dental engineering, decide upon the success or failure should be given special attention. During the preparation of ceramic inlays care should be taken to produce well rounded rather than rectangular edges approximally. In the case of onlays there should ideally be a smooth circular step rounded axially with a sharp-edged near-rectangular interface with the non-ground tooth. Ceramic inlays and onlays are best inserted with the adhesive technique, which provides for an improved strength of the ceramic material, an adequate marginal adaptation and a satisfactory cosmetic appearance. As long-term results are not yet available, the use of ceramic inlays and onlays is still experimental.

[Free mucosal grafting--clinical experiences]. / Klinische Erfahrungen mit dem freien Schleimhauttransplantat.

Free mucosal grafting is a simple, safe and predictable procedure. It is indicated in the treatment of progressive recessions in patients with reduced attached gingiva, in recurrent traumatic marginal lesions inspite of correct tooth brushing, in refractory dental neck hypersensitivity and for cosmetic reasons in patients with recessions. In these situations advancement grafting is done as a secondary procedure. To prevent the potential occurrence of recessions free mucosal grafting may also be indicated prophylactically before orthodontic or prosthetic management. The management concept in patients with recessions as well as the indications of the procedure, the technique used at our department and aspects of planning surgery are discussed.

Space closure in adult patients using the segmented arch technique.

Periodontally compromised adult patients may benefit from modified appliance designs for space closure. TMA T-loops of .016" x .022" and .017" x .025" cross sections, with angulations incorporated via concentrated bends and gradual curvature bends are presented. The force systems these appliances produce are measured, and their clinical performances discussed. Templates for these T-loops are presented. By producing lower forces and higher moment to force ratios, this type of T-loop may benefit patients with bony loss.