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Accuracy of two root canal length measurement devices integrated into rotary endodontic motors when removing gutta-percha from root-filled teeth

Uzun, Orhan, Topuz, O., Tinaz, C., Nekoofar, Mohammad Hossein and Dummer, Paul Michael Howell ORCID: https://orcid.org/0000-0002-0726-7467 2008. Accuracy of two root canal length measurement devices integrated into rotary endodontic motors when removing gutta-percha from root-filled teeth. International Endodontic Journal 41 (9) , pp. 725-732. 10.1111/j.1365-2591.2008.01416.x

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Abstract

Using monomethoxy poly(ethylene glycol) (mPEG)-trypsin conjugates we recently showed that both PEG molecular weight (1100-5000 g/mol) and linker chemistry affect the rate of protein autolysis and thermal stability. These important factors are often overlooked but they can guide the early choice of optimal polymer/chemistry for synthesis of a lead polymer therapeutic suitable for later formulation development. As we are currently developing dextrin- and semi-telechelic poly[N-(2-hydroxypropyl)methacrylamide] (ST-HPMA)-protein conjugates as new therapeutics, the aim of this study was to examine the effect of polymer on activity, autolysis and its thermal stability using trypsin conjugates as a model and compare to the data obtained for mPEG conjugates. Trypsin conjugates were first synthesized using succinoylated dextrin (Mw ∼ 8000 g/mol, dextrin I; or ∼61,000 g/mol, dextrin II), and a ST-HPMA-COOH (Mw ∼ 10,100 g/mol). The conjugates had a trypsin content of ∼54, 17 and 3 wt% respectively with <5% free protein. When amidase activity (KM, Vmax and Kcat) was determined by using N-benzoyl-l-arginine p-nitroanilide (BAPNA) as substrate, trypsin KM values were not altered by conjugation, but the Vmax was ∼6-7-fold lower, and the substrate turnover rate (Kcat) decreased by ∼5-7-fold. The dextrin II-trypsin conjugate was more stable than the other conjugates and native trypsin at all temperatures between 30 and 70 °C, and also exhibited improved thermal stability in the autolysis assays at 40 °C. © 2009 Elsevier B.V. All rights reserved.

Item Type: Article
Status: Published
Schools: Dentistry
Medicine
Uncontrolled Keywords: automated root canal preparation; electronic apex locator; electronic root canal length measurement devices; retreatment; TCM Endo V®; Tri Auto ZX®
Publisher: Wiley & Sons
ISSN: 1365-2591
Last Modified: 18 Oct 2022 13:59
URI: https://orca.cardiff.ac.uk/id/eprint/16103

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