A concept of restorative treatment during orthodontic therapy.

Orthodontic therapy with fixed appliances bears a high risk of plaque accumulation, resulting in demineralization and new carious lesions. Rather than treat incipient lesions in orthodontic patients, most general dental practitioners decide to await future developments. A new concept for comprehensive restorative and endodontic treatment is presented, and its orthodontic implications are discussed.

[An in-vitro study of the interference of orthodontic banding and filling materials]. / In-vitro-Studie der Interferenz von kieferorthopädischer Bebänderung und Füllungswerkstoffen.

Discoloring and layers on bands and restorations during fixed orthodontic therapy are well known clinical phenomenon. Because of the complexity of etiological factors an in-vitro model was used in this study. Aim of the study was to examine the amounts and sort of metals which are dissolved. Therefore, respectively 25 normed MOD-cavities in Frasaco-teeth were filled with a non-gamma-2-amalgam (Amalcap plus, Vivadent) and condensed manually or mechanically. In addition, ten crowns of a high golden (Maingold SG, Heraeus) as well as a palladium basis alloy (Albabond A, Heraeus) were casted. Then they were banded with stainless steel bands (Dentaurum) and cemented with a glass ionomer cement (Ketac Cem, Espe). The probes were given into a 0.1 molar lactic acid for seven days at 37 degrees C. Using ICP (ion coupled plasma) analysis the corrosion solution was examined for elements. High levels of Zn- and Al-ion contents were found, which are components of the used cements. The filling materials themselves mainly set free small amounts of Ag, Sn or Cu. The steel band released Fe, Cr, Ni and Ti. The combination of filling material and band resulted in a higher release of most ions.

[A temperature rise in the dental pulp during the electrothermal removal of ceramic brackets]. / Zur Temperaturerhöhung in der Zahnpulpa während elektrothermischer Abnahme von Keramikbrackets.

The aim of the present in-vitro study was to evaluate the changes in pulp temperature associated with thermal debonding of ceramic brackets using the Ceramic Debonding Unit (Dentaurum). In addition, several forms of false usage were simulated. Instead of thermoelements, the non-contact infrared thermography device SST/THETA 1000 (Heimann) was employed for the dynamic measurement of pulp temperature. Successful debonding after a single activation resulted in a maximal temperature change of 3 degrees C. These in vitro results indicate that the Ceramic Debonding Unit--properly applied--is gentle on the pulp tissue. If debonding fails, the increase in temperature is higher. The influence of differing bracket base morphologies and various resins on electrothermal debonding are discussed.

[Elemental analytical and quantitative morphometric determination of the synthetic resin residues and enamel avulsion after the removal of metal brackets]. / Elementanalytische und quantitativmorphometrische Bestimmung von Kunststoffresten und Schmelzausrissen nach der Abnahme von Metallbrackets.

A number of clinical and experimental studies were performed to assess the quality of the enamel-adhesive-bracket bond. The aim was to present a combined method that enables the investigator both to examine the surface of metal brackets quantitative-morphometrically and to detect the presence of enamel particles. To this end, 38 metal brackets were examined in the scanning electron microscope. An EDAX-detecting unit was used to analyze morphologically conspicuous structures and identified them as enamel particles. The extent of adhesive remnants and enamel particles was quantified using the image analysis system IBAS. In 24 brackets (53%) bonding adhesive residue was found on the bracket base. In 18 brackets (47%) enamel particles were identified on the adhesive-bearing brackets. This method is easier to carry out and enables a more accurate quantification of enamel particles than the Adhesive Remnant Index. Since it can be applied universally to examine recommended improvements to adhesive technique, it facilitates their assessment.

[A comparative study of the possibility of reducing the dosage in lateral teleradiographs]. / Vergleichende Untersuchung zur Möglichkeit der Dosisreduzierung von Fernröntgenseitenaufnahmen.

Thanks to their capability for post-processing of image data, the digital radiological techniques introduced from 1970 onwards permit dose reduction with no loss of clinical information. The aim of this study was to establish the extent of possible dose reduction in orthodontic lateral cephalography. For this purpose, lateral cephalograms of a head phantom taken with varying radiation doses (5 to 150 mAs, constant 70 kV) were evaluated. The evaluations of ten judges were compared statistically. Conventional lateral cephalograms showed a statistically proven superiority of a number of exposure parameters for the sagittal and vertical localisation of reference points. This correlated with the radiological density of the structures. In contrast to the conventional technique, the reference points in all images obtained by digital luminescence radiography showed no such tendency. Digital luminescence thus meets the clinical need to reduce radiation dose (to about 20% of the usual dose) while providing no less diagnostic information.

[Initial experience with digital luminescence radiography in the radiological diagnosis of the visceral cranium]. / Erste Erfahrungen mit der digitalen Lumineszenzradiographie bei der radiologischen Diagnostik des Gesichtsschädels.

The purpose of this study was the evaluation of digital luminescence radiography (PCR; Philips Computed Radiography) used in routine radiological analysis of the facial skull. Besides the standard radiographs additional PCR shots were taken in 16 cases. The subjective evaluation was carried out by three different people using clinical criteria. PCR films showed a significant advantage compared to standard radiographs for the above mentioned applications.

Disfigurement and psychosocial handicap of adults with extreme mandibular prognathism.

Questionnaires and psychological tests were used to assess the psychosocial impact of mandibular prognathism. Patients with mandibular prognathism were asked to assess the impediments caused by their dentofacial deformity. In addition, they were asked to rate their appearance and to report the effect that it had on their social contacts. The self-assessment revealed that patients felt esthetically impaired, but that they had a fairly positive autostereotype, as revealed by their self-descriptive choices on a personality scale. These results were compared with the assessments made by two different control groups composed of persons with no esthetic impairment. The attitudes of the control groups toward the patients were more negative than perceived by the patients, indicating that mandibular prognathism does result in a social handicap.

[The morphological results of the use of a pulsed krypton fluoride excimer laser for enamel conditioning]. / Morphologische Ergebnisse zur Anwendbarkeit eines gepulsten Kryptonfluorid-Excimerlasers im Rahmen der Schmelzkonditionierung.

Although there have been many advances in the field of acid etching, major problems still present. For the most part, these are the unpredictability of the effects of etching, the lack of control of the depth of etching over the long term, and the development of enamel fractures occurring on debonding. The aim of this study was to investigate the morphological effects of enamel conditioning using a pulsed krypton fluoride excimer laser (wavelength 248 nm). Scanning electron microscopic examination revealed a surface similar to that produced by peripheral etching; no signs of thermal damage were to be seen. The requirements that have to be met by a modern laser considered as a possible alternative to conventional acid etching, are discussed.

[Comparative study of the accuracy of localizing cephalometric reference points in using digital and conventional imaging technique]. / Vergleichende Untersuchung zur Genauigkeit der Lokalisierung kephalometrischer Referenzpunkte bei Anwendung digitaler und konventioneller Aufnahmetechnik.

The purpose of this study was to present possible advantages of digital luminescence radiography for cephalometry. Conventional and digitalized lateral headfilms were compared and evaluated. The first impression of an improved simultaneous presentation of bony structures and soft tissue profile in digital x-rays was statistically verified. A significant difference in identification of several reference points was proven by means of the F-test. The superior results of the digital luminescence radiography were evaluated in comparison with xeroradiography and experimental postdigitalization of conventional x-rays.

[Non-contact measurement of the increase in pulp temperature during thermal debonding]. / Mesure sans contact de l'augmentation de la température pulpaire pendant la dépose thermique.

Thermal debonding of ceramic brackets is now used for some time. In this context the possibility of a thermal damage of the pulp is one of the main questions. With the aid of a touchless infrared thermography device (SST/Theta 1,000; Heimann, FRG-Wiesbaden) the consequences of thermal debonding with the "Ceramic Debonding Unit" (Dentaurum, Pforzheim) have been studied. A use according to the manufacturer's device led to temperature changes up to 3 degrees C as maximum. Therefore our in vitro results indicate that the orderly use of the system is safe for the pulp. If the debonding fails, the temperature increase is much higher if the resistance wire is left in place. The influence of different composites is discussed.

[Perceptibility of details in conventional and digital teleradiography--a comparative study]. / Perceptibilité de détails en téléradiographie conventionnelle et digitale--une étude comparée.

By introduction of rare earth film-screen combinations instead of classical screens dose reduction has already been possible. By this study the extent of dose reduction without loss of clinical information was to be examined by comparing conventional radiographic rare earth film-screen combinations to digital radiography. Statistical analysis proves for conventional lateral cephalograms that soft tissue reference points can better be localized if small radiation doses are used. The localization of reference points in areas of less radiographic transparency is better when applying higher doses. These results were not found in images by digital radiographic technique. Reference points both of soft tissue and of more dense areas of the skull were equally to be localized independent from radiation dose by the linear sensibility characteristics of digital radiography. This enables reduction of radiation doses and therefore a contribution to radioprotection.

[Conservation concerns in multiband treatment]. / Konservierende Versorgung während Multibandbehandlung.

If (secondary) caries or amalgam fractures occur during fixed orthodontic treatment, the general dentist usually faces difficulties. Often temporary fillings are inadequate. Due to marginal leakage or break down they may jeopardize an orthodontic result. Step by step four cases of operative dentistry during fixed orthodontics are presented. A wait-and-see attitude or temporary measures for a longer period of time are definitely contraindicated.

Immunization of salmonids against Yersinia ruckeri: significance of humoral immunity and cross protection between serotypes.

Brook trout (Salvelinus fontinalis) were immunized with bacterins containing either Serotype 1 or 2 isolates of Yersinia ruckeri to determine the relative degree of cross-protection afforded when the fish were challenged with the homologous or heterologous serotype. While fish immunized with pH-lysed bacterins produced highly specific agglutinins that did not cross-react with antigens derived from a heterologous serotype of Y. ruckeri all fish were protected against experimental challenge, regardless of which serotype was used for bacterin production and experimental challenge. Other experiments indicated that brook trout injected intraperitoneally with highly specific antibodies could not be passively immunized against experimental challenge.