Murilo Priori Alcalde

Influence of ultrasonic activation of 4 root canal sealers on the filling quality.

INTRODUCTION The purpose of this study was to evaluate the effects of ultrasonic activation on the filling quality (intratubular sealer penetration, interfacial adaptation, and presence of voids) of 4 epoxy resin-based sealers. METHODS Eighty-four extracted human canines were divided into 4 groups (n = 20) according to the sealer used to obturate the root canals instrumented with F5 ProTaper instruments (50/05) (Dentsply Maillefer, Ballaigues, Switzerland). The canals were filled by the lateral compaction technique. Previously, the sealers were labeled with rhodamine B dye to allow analysis under a confocal microscope. At the time of obturation, the specimens were divided again into 2 groups (n = 10) according to the ultrasonic activation of the sealers: ultrasonically activated and nonultrasonically activated groups. All samples were sectioned at 2, 4, and 6 mm from the apex. The percentages of voids, gaps, and dentinal sealer penetration segments of the canal were analyzed. RESULTS Regarding the sealer penetration segments, there was a significant increase for the AH Plus (Dentsply Maillefer), Acroseal (Specialités Septodont, Saint Maur-des-Fossés, France), and Sealer 26 (Dentsply Maillefer) at the 4-mm level and the AH Plus and Sealer 26 at the 6-mm level with ultrasonic activation (P < .05). Concerning the gaps, the ultrasonic activation promoted a smaller presence for all sealers at the 4- and 6-mm levels (P < .05). No statistical significant differences were found for the percentages of voids (P < .05). CONCLUSIONS The use of ultrasonic activation of an epoxy resin-based sealer promoted greater dentinal sealer penetration and less presence of gaps.

Cyclic and Torsional Fatigue Resistance of Reciprocating Single Files Manufactured by Different Nickel-titanium Alloys

Introduction: The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the following reciprocating single‐file systems: ProDesign R 25.06 (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil), Reciproc R25 (VDW GmbH, Munich, Germany), and Unicone L25 (Medin SA, Nové Město in Moravě, Czech Republic). Methods: Sixty instruments of the ProDesign R, Reciproc R25, and Unicone L25 systems (n = 20) were used. Cyclic fatigue resistance was tested measuring the time to failure in an artificial stainless steel canal with a 60° angle and a 5‐mm radius of curvature (n = 10). Torque and angle of rotation at failure of new instruments (n = 10) in the 3 mm from the tip portion were measured during torsional testing according to ISO 3630–1. The fractured surface of each fragment was examined by scanning electron microscopy. Data were analyzed using 1‐way analysis of variance and Tukey tests, and the level of significance was set at 5%. Results: The cyclic fatigue resistance values of ProDesign R 25.06 were significantly higher than the other groups (P < .05). Reciproc R25 showed higher fatigue resistance than Unicone L25 (P < .05). In relation to the torsional test, the ProDesign R 25.06 and Unicone L25 systems showed higher angular rotation until fracture than Reciproc R25 (P < .05). However, Reciproc R25 and Unicone L25 showed higher torque load than ProDesign R 25.06 (P < .05). Scanning electron microscopic analysis showed similar and typical features of cyclic and torsional failure for all instruments tested. Conclusions: ProDesign R presented the highest cyclic fatigue resistance and angular rotation to failure compared with Reciproc and Unicone. However, Reciproc showed higher torsional strength to failure. HighlightsNew reciprocating systems were introduced using different designs and nickel‐titanium (NiTi) alloys.There are no studies regarding the cyclic and torsional fatigue resistance of ProDesign R.There is no report of the torsional properties of Unicone.Different cross‐sectional designs and the types of NiTi alloy affected the cyclic and torsional fatigue resistance of the reciprocating system.ProDesign R had the highest cyclic fatigue resistance values and angular rotation to fracture.Reciproc showed higher torsional strength to failure.

Evaluation of Physicochemical Properties of a New Root Canal Sealer

Introduction: The aim of this study was to evaluate some of the physicochemical properties of a new root canal sealer. Methods: The sealers tested were Sealer Plus compared with AH Plus. For the radiopacity, flow, solubility, and fabrication of test specimens relative to setting times, the American National Standards Institute/American Dental Association No. 57 (2000) and International Organization for Standardization 6876 (2012) specifications were followed. To measure the initial and final setting times, the ASTM C266/2008 standard was used. pH was evaluated in the time intervals of 3, 24, 72, and 168 hours. Statistical tests were applied to the results obtained at a level of significance of 5%. Results: The results demonstrated that the Sealer Plus sealer showed a lower radiopacity value than AH Plus sealer (P < .05); however, this was higher than the minimum value recommended by the specifications (ie, 3 mm Al). Relative to flow, the value for Sealer Plus was 19.19 mm and for AH Plus, 19.81 mm (P > .05). Sealer Plus presented initial and final setting times of 138 minutes and 210 minutes, respectively, whereas the values for AH Plus were 437 minutes and 849 minutes, respectively (P < .05). Relative to solubility, Sealer Plus presented 0.21% and AH Plus, 0.27% (P > .05). None of the sealers showed a significant increase in pH (P > .05). Conclusions: Sealer Plus sealer presented physicochemical properties in accordance with American National Standards Institute/American Dental Association (2000) No. 57 and International Organization for Standardization 6876 (2012) specifications.

Effect of the Association of Nonsteroidal Anti-inflammatory and Antibiotic Drugs on Antibiofilm Activity and pH of Calcium Hydroxide Pastes

Introduction: The objective of the present study was to evaluate the in vitro antibiofilm activity and pH of calcium hydroxide associated with different nonsteroidal anti‐inflammatory drugs (NSAIDs). Methods: The groups analyzed were as follows: group 1, calcium hydroxide paste with propylene glycol; group 2, calcium hydroxide paste with propylene glycol + 5% diclofenac sodium; group 3, calcium hydroxide paste with propylene glycol + 5% ibuprofen; group 4, calcium hydroxide paste with propylene glycol + 5% ciprofloxacin; and group 6, positive control (without medication). For analysis of the pH, the pastes were inserted into tubes and immersed in flasks containing ultrapure water. At the time intervals of 3, 24, 72, and 168 hours, the pH was measured with a calibrated pH meter. For microbial analysis, biofilm was induced in 30 bovine dentin blocks for 21 days. Subsequently, the pastes were placed on the blocks with biofilm for 7 days. Afterward, the pastes were removed by irrigation with sterile water, and the specimens were analyzed with a laser scanning confocal microscope with the 50 &mgr;L Live/Dead BacLight Bacterial Viability solution L7012 Kit (Molecular Probes, Inc, Eugene, OR). Data were subjected to statistical analysis at a significance level of 5%. Results: The highest pH values were found for calcium hydroxide associated with ciprofloxacin in all periods analyzed. With the exception of pure calcium hydroxide paste, the other groups showed statistically significant differences (P < .05) in comparison with the positive control. Conclusions: The association of NSAIDs or antibiotic did not interfere with the pH of calcium hydroxide paste and increased the antimicrobial action of calcium hydroxide paste against Enterococcus faecalis biofilm formation. Highlights:We evaluated the association of nonsteroidal anti‐inflammatory drugs (NSAIDs) with calcium hydroxide (CH) on the pH and antimicrobial action against Enterococcus faecalis.The association of NSAIDs or antibiotics did not interfere with the pH of CH paste.Diclofenac sodium promotes the antimicrobial action of CH against E. faecalis.

Correction to: Cyclic fatigue and torsional strength of three different thermally treated reciprocating nickel-titanium instruments

The original version of this article contained a mistake. The name Jader Carvalho Pinto should have been Jader Camilo Pinto.

Evaluation of Different Passive Ultrasonic Irrigation Protocols on the Removal of Dentinal Debris from Artificial Grooves.

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.

Effect of ultrasonic agitation on push-out bond strength and adaptation of root-end filling materials

Objectives This study evaluated the effect of ultrasonic agitation of mineral trioxide aggregate (MTA), calcium silicate-based cement (CSC), and Sealer 26 (S26) on adaptation at the cement/dentin interface and push-out bond strength. Materials and Methods Sixty maxillary canines were divided into 6 groups (n = 10): MTA, S26, and CSC, with or without ultrasonic activation (US). After obturation, the apical portions of the teeth were sectioned, and retrograde cavities were prepared and filled with cement by hand condensation. In the US groups, the cement was activated for 60 seconds: 30 seconds in the mesio-distal direction and 30 seconds in the buccal-lingual direction, using a mini Irrisonic insert coupled with the ultrasound transducer. After the materials set, 1.5-mm thick sections were obtained from the apexes. The presence of gaps and the bond between cement and dentin were analyzed using low-vacuum scanning electron microscopy. Push-out bond strength was measured using a universal testing machine. Results Ultrasonic agitation increased the interfacial adaptation of the cements. The S26 US group showed a higher adaptation value than MTA (p < 0.05). US improved the push-out bond strength for all the cements (p < 0.05). Conclusions The US of retrograde filling cements enhanced the bond to the dentin wall of the root-end filling materials tested.

Canal Transportation, Centering Ability, and Cyclic Fatigue Promoted by Twisted File Adaptive and Navigator EVO Instruments at Different Motions

Introduction This study compared the cyclic fatigue and the canal transportation promoted by Twisted File (TF) Adaptive and Navigator EVO systems when used with 2 different motions. Methods Forty mesiobuccal roots of maxillary molars were scanned by using micro–computed tomography imaging before and after root canal preparation with the 2 instrument systems used with 2 motions (adaptive and continuous rotation). Samples were divided into 4 groups: TFA, TF Adaptive instruments under adaptive motion; TFC, TF Adaptive instruments under continuous motion; NA, Navigator instruments under adaptive motion; and NC, Navigator instruments under continuous motion. Root canals were prepared until 35.04 instruments. Apical transportation was analyzed by using micro–computed tomography at 3 levels: 3, 6, and 9 mm from the apex. The cyclic fatigue tests were performed by using a custom‐made device. Ten instruments of each brand were activated by using a 6:1 reduction handpiece powered by a torque‐controlled motor using the preset programs “custom mode” and “TF Adaptive” to activate 25.06 and 35.04 instruments. Kruskal‐Wallis and Dunn tests were used to assess canal transportation, centering ability, and canal volume. The Student t test was used to evaluate cyclic fatigue (P = .05). Results At 3 and 9 mm, the canal transportation and centering ability were similar in all groups (P > .05). At 6 mm, TFC presented higher canal transportation toward furcal region than NA and NC (P < .05). After canal preparation, TFA promoted great dentinal excision, presenting higher canal volume than NA and NC (P < .05). Higher cyclic fatigue resistance was observed under continuous than adaptive motion regardless of system or tip/diameter of the instrument (P < .05). Conclusions Both systems can be used under adaptive or continuous rotation. However, the life span of the instruments was higher when used under continuous rotation. Small canal transportation occurred when mesiobuccal root canals from maxillary molars were prepared until 35.04 instruments. HighlightsTFC presented canal transportation toward furcal region at 6 mm from the apex.Higher canal volumes were observed in TFA.Centering ability was similar in all groups.Files presented higher cyclic fatigue resistance under continuous than adaptive motion.Both systems can be used under adaptive or continuous rotation.

A novel ultrasonic tip for removal of filling material in flattened/oval-shaped root canals: a microCT study

The aim of this study was to evaluate the influence of a novel ultrasonic tip as an auxiliary method for removing filling material from flattened/oval-shaped canals. The null hypothesis tested was that this method does not influence removing the filling material in flattened/oval-shaped canals. Forty-five mandibular incisors were selected and randomly divided into three experimental groups (n = 15) according to different protocols for removing root canal filling material. Group R: Reciproc R25/.08, Group RC: Reciproc R25/.08 + Clearsonic tip, and Group CR: Clearsonic tip + Reciproc R25/.08. The teeth were scanned pre and post-operatively by means of a micro-computed tomography system. Data were analyzed using non-parametric Kruskal-Wallis and Dunn tests (p < 0.05). The percentage of residual root canal filling material between the experimental groups was examined. Statistically significant differences between the experimental groups were found in the root canal. Group R had the highest percentage of residual root canal filling material when compared with Groups RC and CR. The lowest percentage of residual root canal filling material was observed in Group CR. In the apical third of the root canal, statistically significant differences were found between the different protocols. The use of the ClearSonic tip followed by the Reciproc 25/.08 file to remove filling material resulted in the lowest percentage of residuals in the whole root canal and in the apical third.

Intradentinal antimicrobial action and filling quality promoted by ultrasonic agitation of epoxy resin-based sealer in endodontic obturation

Abstract The aim of this study was evaluate the influence of ultrasonic activation (UA) of AH Plus to improve canal and isthmus filing, and analyse the antimicrobial effect against Enterococcus faecalis within dentinal tubules. Material and Methods: Thirty mesial roots of mandibular first molars were selected and divided into 2 groups (n = 15): with and without UA of the sealer. Then the root canals were filled by using the single cone technique, and the specimens were sectioned at 2, 4 and 6 mm from the apex for stereomicroscope and confocal laser scanner microscopy (CLSM) analysis. In addition, 30 bovine incisors were contaminated with Enterococcus faecalis and divided into 3 groups (n = 10). The specimens were obturated by using the single cone technique with (G1) and without (G2) UA of the sealer and G3 as the control group. All were sectioned into 6 mm-long cylinders and stained with LIVE/DEAD to assess bacterial viability by CLSM. Results: The UA of the sealer significantly reduced the presence of unfilled areas in the canal and isthmus area in all sections (p<0.05), and there was a significant increase in sealer penetration in both canals and isthmuses (p<0.05). As regards gaps, a significant reduction was found at 2 and 6 mm in the isthmus area of the UA group (p<0.05). Moreover, UA of the sealer significantly reduced bacterial viability in the superficial dentine when compared with the other groups (p<0.05). Conclusion: Ultrasonic activation of the AH Plus sealer promoted a better quality of root canal filling and increased the intratubular penetration of sealer, especially in the isthmus area. Additionally, ultrasonic activation of the sealer increased the intradentinal antimicrobial action against Enterococcus faecalis, mainly in the superficial dentine of the root canal.