Analysis of forces developed during mechanical preparation of extracted teeth using Profile NiTi rotary instruments.

AIM: The aim of this study was to analyse the vertical forces and torque developed in the root canal system of extracted teeth during mechanical preparation using ProFile NiTi instruments. METHODOLOGY: Instrument wear and fracture is in great part due to the repeated application of forces and torque during the course of root-canal preparation but research into the direct relationship has been hampered by the lack of adequate measuring devices. Measurements of these forces and torque were made with a new force analyser device, the Endographe, that was equipped with a holder to record and generate graphs of the vertical forces and torque exerted during the preparations. These preparations was performed by endodontists or students either with a series of instruments of increasing size or with the crown-down pressureless technique. RESULTS: The mean values for the endodontists of the generated vertical forces and torque varied, respectively, from 4 to 6N and from 7.105 to 12.105 Nm for the step-back technique and from 2.9 to 4.2 N and from 18.105 to 20.105 Nm for the crown-down technique. This suggested that the crown-down technique generated lower stresses (lower torque and lower vertical forces), although these findings also depend on the shape of individual canals. The students initially showed wide variations in generated forces, with significantly lower vertical force the torque values. By the end of the experimental sessions their values were similar to those of the endodontists, which indicated improvement in the efficiency of manipulation. CONCLUSIONS: Further work is needed to investigate the relationship between the force and the torque data from this study and the incidence of instrument fracture with the two techniques, as the clinical implications are considerable. It must be noted, however, that the Endographe is unable to take into account the cutting efficiency of the instruments. The use of graphs provides a new approach to the analysis of mechanical preparation.     

The bedtime pass: an approach to bedtime crying and leaving the room.

OBJECTIVE: To evaluate a novel intervention for bedtime problems. DESIGN: We used an ABAB withdrawal-type experimental design. SETTING: The intervention was prescribed in an outpatient primary health care context and evaluated in the home setting. PARTICIPANTS: Two normally developing boys aged 3 and 10 years were the primary participants. Twenty parents and 23 practicing pediatricians rated the acceptability of the intervention. INTERVENTION: A bedtime pass, exchangeable for 1 excused departure from the bedroom after bedtime. MAIN OUTCOME MEASURES: For both primary participants, instances of crying and/or coming out from the bedroom after bedtime; for the 20 parents and 23 pediatricians, comparative ratings of acceptability for the pass and 2 other commonly used approaches to bedtime problems (ignoring crying and letting children sleep with their parents). RESULTS: Crying and coming out from the bedroom reduced to zero rates in both children. Pediatricians rated using the pass as significantly more acceptable than letting children sleep with parents and equivalent to ignoring. Parents rated the pass as more acceptable than either alternative. CONCLUSION: The bedtime pass provides pediatricians with a readily usable, potentially effective, and highly acceptable novel intervention for bedtime problems, one of the most common complaints in outpatient pediatrics.     

Buchbesprechungen

Ohne Zusammenfassung     

Zur Frage der Unterscheidbarkeit vitaler und postmortaler Gewebsveränderungen am Beispiel der Strangfurchen beim Erhängungstod

Ohne Zusammenfassung     

Akute tödliche Quecksilberdermatitis durch weiße Praezipitatsalbe

Zusammenfassung Bei einem jungen Manne entwickelt sich nach viermaligem Bestreichen einer ungef?hr 3 qdm gro?en, durch eitrige Follikulitis krankhaft ver?nderten Hautoberfl?che mit 10proz. wei?er Praezipitatsalbe eine akute, vorerst lokalisierte, dann generalisierte Hg-Dermatitis. Nach vorübergehender Besserung kommt es zur Bildung subkutaner, nach au?en durchbrechender Abszesse, die schulie?lich über den ganzen K?rper ausgebreitet, 40 Tage nach Auftreten des Exanthems ad exitum führen.     

Nachprüfung der Siliquidreaktion nach Blumenthal und Schirakawa an 250 Fällen von Lues des Zentralnervensystems

Zusammenfassung Auf Grund unserer umfangreichen Untersuchungen möchten wir in Verbindung mit den anderen Liquorreaktionen auf die Siliquidreaktion nicht mehr verzichten; Gründe, die gegen eine Spezifität sprechen, haben wir nicht gefunden. In Anbetracht der leichten Ausführbarkeit dürfte die Reaktion auch für den Praktiker, soweit er überhaupt Liquorreaktionen ausführt, sehr zu empfehlen sein.