Syringe irrigation in confluent canals: A sequential computational fluid dynamics assessment

This study aims to assess the influence of root canal preparation, irrigation needle design and its placement depth in the irrigation flow of confluent canals during syringe irrigation. A mandibular molar presenting two confluent canals in its mesial root was sequentially prepared and scanned by micro-computed tomography after mechanical preparation up to ProTaper Next system sizes X2 (25/.06v), X3 (30/.07v) and X4 (40/.06v). In each of the root canal preparation models, a side-vented and an open-ended needle at 5, 3 and 2 mm from the working length were included, and irrigation flow was assessed by a validated computational fluid dynamics model. The results revealed that the irrigant flowed out of the confluent canals mainly through the canal that did not have the needle. Apical penetration and renewal of the irrigant were most efficiently achieved with the use of a 30G open-ended needle and a 30/.07v preparation.

Root canal debridement by negative pressure irrigation, ultrasonically activated irrigation and their combination

Despite scientific evidence that root canal debridement is the cornerstone for successful treatment, the effectiveness of a combination of delivery and activation systems in cleaning root canals remains unknown. This study is the first to demonstrate the remaining pulp tissue in root canals after irrigation with various techniques such as positive pressure syringe-and-needle irrigation, ultrasonic activation, negative pressure irrigation and ultrasonic activation after negative pressure irrigation. The results showed that negative pressure irrigation alone and its combination with ultrasonic activation resulted in significantly superior effectiveness than positive pressure irrigation and ultrasonic activation alone in the apical-third of root canals.

Comparison of Conventional Syringe, CanalBrush, EndoActivator, Photon-Induced Photoacoustic Streaming, and Manual Instrumentation in Removing Orange-Brown Precipitate: An In Vitro Study

OBJECTIVE

The aim of this in vitro study was to compare the various techniques for removing precipitate formed after irrigation with sodium hypochlorite (NaOCl) and chlorhexidine (CHX).

BACKGROUND DATA

It is still unclear whether different irrigant activation systems can effectively remove precipitate that is firmly attached to the root canal walls.

METHODS

Eighty-two extracted single-rooted human teeth were instrumented by using the ProTaper rotary system. The roots were irrigated with 5% NaOCl and then 2% CHX to form orange-brown precipitate on the root canal walls. The teeth were sectioned longitudinally, and the amount of precipitate on the canal walls was measured under a stereomicroscope at 15 × magnification before the root halves were reassembled. Then, conventional syringe irrigation (CSI), CanalBrush (CB), EndoActivator (EA) system, photon-induced photoacoustic streaming (PIPS), and manual instrumentation (MI) techniques were used to remove the precipitate, during which 5 mL of distilled water was used for 1 min. The amount of precipitate remaining on the canal walls was measured, and the percentage of precipitate removed was calculated. Data were analyzed by using the Kruskal-Wallis and Mann-Whitney U tests (p = 0.05).

RESULTS

All experimental groups contained residual precipitate. The precipitate was more effectively removed in the MI group than in the other groups (p < 0.05). The CB and EA groups showed better removal than the CSI and PIPS groups (p < 0.05), and there were no significant differences in removal between these latter two groups (p > 0.05).

CONCLUSIONS

None of the techniques used was able to completely remove the orange-brown precipitate from the root canal surfaces.

[Cleaning effect of ultrasonic activation as an adjunct to syringe irrigation of root canals: a systematic review]

OBJECTIVE

To investigate evidence supporting whether ultrasonic irrigation as a supplement is more effective than syringe irrigation in root canal cleaning.

METHODS

An electronic search was conducted in PubMed, Embase, Web of Science, Cochrane Library, ProQuest Dissertation and Theses, Database for Chinese Technical Periodicals, China National Knowledge Infrastructure, Wanfang Database, and Chinese Biomedical Literature Database. Studies were retrieved from January 1, 1985 to March 1, 2014. The Chinese journals on stomatology and the bibliography of all relevant articles were manually searched. Relevant clinical randomized controlled trial (RCT) and clinical controlled trial (CCT) were selected. Two investigators evaluated the risk of bias of the included trials in accordance with Cochrane risk of bias assessment tools and collected data of included studies. Meta-analysis was then performed in RevMan 5.2.

RESULTS

Nine articles that satisfied the eligibility criteria were included in this Meta-analysis. Seven studies showed low bias risk, and the remaining studies exhibited moderate bias risk. Histological results showed that ultrasonic irrigation supplement could significantly improve canal and isthmus debridement at the apical area (P < 0.01). Antibacterial efficacy was evaluated by bacterial culture (P = 0.26) and polymerase chain reaction (P = 0.99) methods, no significant differences in antibacterial efficacy were observed.

CONCLUSION

Ultrasonic irrigation supplement is more effective than syringe irrigation in root canal debridement at the apical area. However, antibacterial efficacy is not statistically significant.