Journal of endodontics
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Journal of endodontics · Jun 2013
Hypotonic-induced stretching of plasma membrane activates transient receptor potential vanilloid channels and sodium-calcium exchangers in mouse odontoblasts.
A number of transient receptor potential (TRP) channels have been identified as membrane-bound sensory proteins in odontoblasts. However, the activation properties of these channels remain to be clarified. The purpose of this study was to investigate hypotonic stimulation-induced Ca(2+) entry via TRP vanilloid subfamily member (TRPV) 1, TRPV2, and TRPV4 channels, which are sensitive to osmotic and mechanical stimuli, and their functional coupling with Na(+)-Ca(2+) exchangers (NCXs) in mouse odontoblast lineage cells. ⋯ These results indicate that stretching of the odontoblast membrane activates TRPV1-, TRPV2-, and TRPV4-mediated Ca(2+) entry, and increased intracellular-free Ca(2+) concentration is extruded via NCXs. These results suggest that odontoblasts can act as sensors that detect stimuli applied to exposed dentin and drive a number of cellular functions including dentinogenesis and/or sensory transduction.
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Journal of endodontics · May 2013
Randomized Controlled Trial Comparative StudyA prospective, randomized, double-blind comparison of the injection pain and anesthetic onset of 2% lidocaine with 1:100,000 epinephrine buffered with 5% and 10% sodium bicarbonate in maxillary infiltrations.
Local anesthetics can be buffered to a physiological pH before injection to decrease the time of onset and reduce injection pain. ⋯ Two percent lidocaine with 1:100,000 epinephrine buffered with 5% or 10% sodium bicarbonate did not differ from nonbuffered solutions in anesthetic onset or injection pain in maxillary infiltrations of canines with healthy pulps.
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Journal of endodontics · May 2013
Second canal in mesiobuccal root of maxillary molars is correlated with root third and patient age: a cone-beam computed tomographic study.
There is little evidence supporting the use of cone-beam computed tomographic (CBCT) scanning in root canal anatomy investigation. This study aimed to investigate the presence of second mesiobuccal canals (MB2) in different thirds of the mesiobuccal root of first and second maxillary molars using CBCT scanning and to correlate findings with patient sex and age. ⋯ The prevalence of MB2 canals decreases as the root canal approaches the apical third and as age increases. No association with sex was observed. CBCT scanning proved effective in mapping MB2 canals present in different thirds of the root.
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Journal of endodontics · Apr 2013
Apical pressure and extent of irrigant flow beyond the needle tip during positive-pressure irrigation in an in vitro root canal model.
This study aimed to measure the pressure generated during positive-pressure irrigation at the periapex of an in vitro tooth model using a novel method of measurement, investigating the effect of flow rate and needle design. Apical pressure was correlated with the extent of dye clearance from the end of a needle tip in a plastic root canal model with similar dimensions. ⋯ If apical clearance of dye beyond the needle tip is a measure of irrigation effectiveness, then maximum effectiveness with safe apical pressures can be gained at specific flow rates using specific needle tip designs. The use of an irrigation flow rate of 4 mL/min was able to achieve maximum effectiveness in this study.
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Journal of endodontics · Apr 2013
Periapical pressures developed by nonbinding irrigation needles at various irrigation delivery rates.
Injection of sodium hypochlorite (NaOCl) from the root canal into periapical tissues may result in a NaOCl incident. The purpose of this study was to examine the fluid pressure generated by canal cleansing devices at the apical interface, when the tip of the irrigation device was not binding to the canal walls. ⋯ Positive apical irrigation pressures in excess of the central venous pressure may be generated by some canal cleansing devices when irrigants are delivered at flow rates higher than 1 mL/min, even when the irrigation needle is not wedged into the canal walls.