Abstract
The aim of this study was to evaluate the influence of different passive ultrasonic irrigation protocols on the removal of debris in artificially created grooves in the cervical, middle and apical root thirds. Forty extracted bovine incisor roots were instrumented to 1 mm of the root apex with a R50 Reciproc instrument and irrigated with 2.5% sodium hypochlorite. The roots were then inserted in a muffle and cleaved into two hemisections. Grooves (3-mm long) were done at 2, 7 and 12 mm from the root apex in one hemisection and filled with dentinal debris. The hemisections were regrouped into the muffle and divided into 4 groups (n=10) according to the final irrigation protocol: Control group: 3x20 s using a #30 gauge needle without agitation of the irrigating solution; Group PUI-s (static passive ultrasonic irrigation): 3x20 s of passive ultrasonic irrigation with the tip of the insert maintained static on the apical third; Group PUI-t (passive ultrasonic irrigation per third): 20 s of PUI in each third; Group PUI-d (passive dynamic ultrasonic irrigation): 3x20 s of PUI dynamically moving the insert in the whole extent of the root canal. In all groups, was used a total of 6 mL of 2.5% sodium hypochlorite as irrigant. After these procedures, the grooves were analyzed with a stereomicroscope and assigned scores as regards removal of the debris. The data were analyzed statistically (a=0.05). The results showed a better cleaning in all the groups where the irrigating solution was agitated with ultrasonic device than in the control group (p<0.05). In the apical third, the PUI-d and PUI-s showed similar performance (p>0.05) and a better cleanness than PUI-t (p<0.05). The dynamic and static methods of agitation of the irrigating solution provided more effective cleaning. PUI-d provided the most completely clean grooves suggesting that its use is the most adequate in cases of teeth with complex canal anatomy.
Highlights
The anatomy of the root canal system is complex, with areas of irregularities, isthmuses, lateral canals and apical deltas, favoring the presence of microorganisms [1,2] and tissues, as well as the accumulation of dentinal debris after instrumentation [3]
The same was observed in the middle third, except for the Passive ultrasonic irrigation (PUI)-t group, which had no statistical difference to any group
The present study evaluated the ability of debris removal in artificial irregularities made in cervical, middle and apical thirds, depending on different methods of passive ultrasonic irrigation (PUI)
Summary
The anatomy of the root canal system is complex, with areas of irregularities, isthmuses, lateral canals and apical deltas, favoring the presence of microorganisms [1,2] and tissues, as well as the accumulation of dentinal debris after instrumentation [3]. Several studies made with agitation of the irrigant with ultrasonic tips advise that they be inserted 1 mm from the working length and perform 3x20 s agitations, being the most common protocol in Endodontics [14,15,16,17]. These studies used in vitro methodologies with grooves made only in the apical portion of the root canal. There is little information in The literature is scarce on data that evaluate whether the dynamic use of the ultrasonic insert (with movement of the tip), or agitation by thirds have similar or better results when the tip remains in a static position, 1 mm from the working length
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