Der Einsatz des Prophy-Jet®-Gerätes zur Schmelzpolitur nach der Bracketentfernung

Zusammenfassung In einer In-vitro-Studie wurde die Einsatzfähigkeit des Prophy-Jet-^®-Gerätes für die Schmelzpolitur nach Bracketentfernung untersucht. In die Studie wurden drei verschieden stark gefüllte orthodontische Kleber einbezogen: Concise^®, Genie^® und Mono Lok^®. Alle Proben wurden rasterelektronenoptisch untersucht und fotografisch dokumentiert in Vergrößerungen zwischen 20- und 10 000fach. Die Oberflächenanalyse ergab, daß das Prophy-Jet^®-Gerät allein zur Schmelzpolitur nach Bracketentfernung nicht ausreicht, um unter klinisch vertretbarem Zeitaufwand (1 Minute/Zahn) eine kunststofffreie Schmelzoberfläche zu erzielen. Nach konventioneller makroskopischer Vorreinigung mit Scalern oder rotierenden Hartmetallfinierern zeigten sich nach fünfsekündiger Prophy-Jet^®-Bestrahlung noch geringe Kleberreste. Nach zehnsekündiger Expositionsdauer waren beim Mono Lok^®-Adhäsiv keine Kleberreste mehr nachweisbar, beim Concise^®-bzw. Genie^®-Adhäsiv fanden sich noch vereinzelte geringe Kleberinseln. Das Prophy-Jet^®-Gerät erscheint zur Unterstützung der Schmelzpolitur nach Bracketentfernung sinnvoll; eine sorgfältige Vorreinigung mit Hand- oder rotierenden Instrumenten ist jedoch erforderlich, um eine weitgehende Adhäsivreduktion zu erreichen. Die konventionelle Gummi- und Bimssteinpolitur kann nach 20sekündiger Prophy-Jet^®-Bestrahlung entfallen.

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Summary The purpose of this in vitro investigation was to ascertain the effects of the Prophy-Jet^® air-powder abrasive system for enamel polishing after debonding. Three adhesives differing in filler content were included in this study: Concise^®, Genie^®, and Mono Lok^®. All specimens were examined by scanning electron microscopy and documented photographically at magnifications from 20 to 10 000. Surface analysis showed that using the Prophy-Jet^® exclusively is not sufficient to produce a clean and smooth enamel surface without residual adhesive after debonding and after one minute of exposure time, as might be justifiable in a clinical situation. After macroscopic conventional clean-up with scalers or rotary finishing instruments and five seconds of exposure time to the Prophy-Jet^® some occasional adhesive remnants could be located. After ten seconds of Prophy-Jet^® treatment all Mono Lok^®-adhesive was removed from the enamel surface; in the Concise^® and Genie^®-group few isolated adhesive remnants could be detected. The Prophy-Jet^® air-powder abrasive system was found to be efficient in supporting enamel polishing after debonding; but an accurate pretreatment with scalers or rotary finishing instruments is essential to achieve an extensive reduction of adhesive. Final polishing of the enamel surface with rubber wheels or prophy cup and pumice can be omitted after treatment with the Prophy-Jet^® for 20 seconds.

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Résumé Le but de ce travail était d'éxaminer à l'aide d'une étude in vitro, l'emploi du Prophy Jet^® pour le polissage de l'émail après l'arrachage des brackets. Dans l'étude on a analysé trois substances adhésives différentes: Concise^®, Genie^® et Mono Lok^®. Après avoir examiné les spécimens par le microscope électronique à balayage, on les a documentés à l'aide de photos d'un grossissement de 20 à 10 000. L'analyse de la surface montre que la seule application du Prophy Jet^® (après l'arrachage des brackets) ne suffit pas pour obtenir une surface d'émail sans substance adhésive en un temps clinique d'une minute par dent. Après prétraitement macroscopique selon la méthode conventionnelle (scaler ou instruments montés sur tour) il demeurait encore de petits restes de la substance adhésive après l'application du Prophy Jet^® pendant cinq secondes. Après une durée d'application de dix secondes, on ne pouvait pas déceler de restes de Mono Lok^®, tandis qu'il y avait sporadiquement des restes de Concise^® et Genie^®. Ces résultats indiquent, que le Prophy Jet^® est efficace pour le polissage de l'émail après l'arrachage des brackets, mais on a tout de même besoin d'un nettoyage précédent minutieux avec des instruments convenables (scaler ou instruments montés sur le tour) pour obtenir une réduction considérable de la substance adhésive. On peut renoncer au polissage conventionnel à l'aide de caoutchouc ou de la pierre ponce après l'application du Prophy Jet^® pendant 20 secondes.

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Vortrag auf der wissenschaftlichen Jahrestagung der Deutschen Gesellschaft für Kieferorthopädie 1985.     

An epitope shared by central nervous system myelin and peripheral blood macrophages

Lewis rats were immunized with a homogenate of human spinal cord. Splenocytes from the immunized rats were fused with cells from the SP2/0-Ag14 cell line to form hybrids that were subsequently screened immunohistochemically for secretion of antibodies against myelin. Thirty hybrids secreting anti-myelin antibodies were cloned. One secreted antibody (774) that immunohistochemically stained central nervous system (CNS) myelin but not peripheral nervous system (PNS) myelin also bound to the surface of peripheral blood macrophages. Hence we have identified an epitope that is shared by peripheral blood macrophages and CNS myelin.     

Necrosis of the femoral head following fracture of the femoral neck

One hundred and thirty fractures of the femoral neck treated with sliding screw-plate or sliding nail-plate were followed for up to 65 months postoperatively. Throughout the observation period the yearly incidence of necrosis of the femoral head was between 5 and 10 per cent, as estimated by the life table method, and after 5 years 37 per cent of the patients with united fractures had developed necrosis of the femoral head. The cases of necrosis were all characterized radiographically by one or more areas of subchondral cortical depression, generalized subchondral fragmentation or isolated patches of sclerosis. It is concluded that estimation of the frequency of femoral head necrosis after fracture of the femoral neck requires long-term follow-up and reliable, reproducible radiographical criteria for necrosis of the head. Because of the high mortality of patients sustaining these fractures, statistical methods employing censored data should be used.     

Is vasoactive intestinal polypeptide the principal transmitter involved in human penile erection?

Previous work from this laboratory reported on the effects of several autacoids and other agents on strips of human corpus cavernosum (cc) muscle. These investigations indicated the presence in the cc muscle of a) atropine-sensitive cholinoceptors, b) alpha- and beta-adrenoceptors and c) a non-adrenergic non-cholinergic mechanism. Several recent publications have presented evidence in support of the possibility that vasoactive intestinal polypeptide (VIP) is an important, or the chief, transmitter in human penile erection. This paper describes the actions of VIP and other compounds on the cc muscle and the effect of intracavernous injection of VIP in volunteers. Among the agents tested, VIP was the most potent relaxant of the cc muscle. This effect, which was seen at a dose as low as 0.03 nM, was suppressed by VIP antiserum. The response of the isolated penile vasculature to VIP was similar. VIP antiserum had no effect on the relaxation of the cc muscle produced by field stimulation. In five of the seven subjects given intracavernous VIP (1.0 micrograms.) some degree of penile enlargement was evident, but none had an erection. It is suggested that local release of VIP, withdrawal of the alpha-adrenoceptor mediated tonic supply to the penis and the activation of the latter's beta-adrenoceptors are all probably involved in penile erection in man.     

Digital tourniquets: a pressure study with clinical relevance

This study measured the pressures under the three most commonly used digital tourniquets--the Penrose drain, the rolled rubber glove, and the rubber band. A miniature pressure transducer and a digital strain indicator were used to measure pressures generated by the various tourniquets. The rolled rubber glove technique was highly consistent, irrespective of the clinical experience of the subject, and uniformly generated pressures of less than 500 mm Hg. Pressures generated by Penrose drains and rubber bands were highly variable and were significantly greater than 500 mm Hg. The so-called calibrated Penrose drain generated the highest pressures in the study. The relationship between tourniquet pressures and neurovascular injury in the human digit is not clearly defined.     

Pharmacological analysis of the interaction between Bay K 8644 and 5-HT in rabbit aorta

Bay K 8644 potentiated and augmented 5-hydroxytryptamine (5-HT)-induced contractions in the rabbit, isolated aorta preparation, as manifested in leftward shift and increase in the asymptote of 5-HT E/[A] (effect vs concentration) curves. The operational model of agonism (Black & Leff, 1983) was used to analyse this interaction and the concomitant effects of irreversible receptor alkylation by phenoxybenzamine. The competitive effects of spiperone in the presence and absence of Bay K 8644 were also examined. From these analyses it is concluded that Bay K 8644 elicits its potentiating effects by increasing the efficacy of 5-HT at the 5-HT2 receptor with no alteration in affinity. This is consistent with the known effect of Bay K 8644 of causing an increase in the functional concentration of plasmalemmal calcium channels coupled to the 5-HT2 receptors in this preparation. The positively co-operative shape of the 5-HT E/[A] curves obtained in the aorta and the quantitative nature of their potentiation by Bay K 8644 indicated that the coupling of 5-HT2 receptor occupancy to intracellular calcium concentration is linear and that the co-operativity resides in the subsequent relation between intracellular calcium and pharmacological effect. Bay K 8644 may serve as a probe for differentiating between the types of calcium channels that transduce 5-HT receptor-mediated effects in different systems. Such information would be useful in the classification of agonist interactions with 5-HT receptors.