Chemomechanical Preparation Research Articles

Quantitative evaluation of debris extruded apically using reciprocating versus continuous rotation single file with rotary and hand glide path file

Chemomechanical root canal preparation (CMRCP) is an important step in root canal treatment. However, one of its negative consequences is apical extrusion of debris of the root canal system contributing to treatment failure and flare-ups. Glide path preparation (GPP) is the initial phase of CMRCP and is crucial for assessing root canal anatomy and establishing unobstructed access to the apical part of the canal. Materials and methods: Forty human mandibular permanent central and lateral incisors were selected; the debris collection apparatus was prepared and the teeth were then divided into four groups: Group 1: Rotary glide path preparation with ProGlider followed by instrumentation with Wave One files. Group 2: Rotary glide path preparation with ProGlider followed by instrumentation with One Shape files. Group 3: Hand glide path preparation with K-file followed by instrumentation with Wave One files. Group 4: Hand glide path preparation with K-file followed by instrumentation with One Shape files. The collected debris was weighed in an analytical digital balance and the collected data were statistically analyzed. Results: No significant difference was present between groups with the same method of glide path preparation or between Wave One and One Shape files. Rotary glide path preparation produced less debris than hand preparation (p≤0.05). Conclusions: Extrusion of debris was observed in all test groups. Rotary glide path preparation could be preferred in clinical practice as it is associated with less debris extrusion than the manual method.

Root Canal Disinfection by Single- and Multiple-instrument Systems: Effects of Sodium Hypochlorite Volume, Concentration, and Retention Time

IntroductionThis ex vivo study evaluated the intracanal bacterial reduction promoted by chemomechanical preparation using a single-file technique varying the volume, concentration, and retention time of sodium hypochlorite (NaOCl) irrigation in comparison with a multifile system. MethodsPalatal roots from extracted maxillary first molars were selected and anatomically matched based on microcomputed tomographic analysis for group distribution. The canals were contaminated with a fresh mixed bacterial culture grown in anaerobiosis and recently obtained from a tooth with apical periodontitis. Specimens were divided into 4 groups of 24 each according to the following preparation protocols: REC-6LOW (Reciproc R50 instrument [VDW, Munich, Germany], 6% NaOCl, low irrigant volume), REC-2.5LOW (R50, 2.5% NaOCl, low irrigant volume), REC-2.5HI (R50, 2.5% NaOCl, high irrigant volume), and BR-2.5HI (BioRaCe [FKG Dentaire, LaChaux-de-Fonds, Switzerland], 2.5% NaOCl, high irrigant volume). The total time of preparation was recorded. Intracanal bacteriologic samples were taken before and after preparation; DNA was extracted and subjected to quantitative polymerase chain reaction. ResultsBacteria were detected in 22 initial samples from the REC-2.5LOW group and in 23 from the other groups. Intragroup analysis showed that all tested preparation protocols were highly effective in significantly reducing the intracanal bacterial counts (P < .001). Intergroup comparison of bacterial reduction levels revealed a statistically significant difference between BR-2.5HI and REC-2.5LOW (P < .05). Counts of bacteria were 2.5 times significantly higher in REC-2.5LOW compared with BR-2.5HI. No other significant differences were found in quantitative findings (P > .05). ConclusionsThe concerted effects of multiple instruments, the high volume of irrigation, and the long retention time of NaOCl irrigant had a positive influence on intracanal disinfection during chemomechanical preparation.

Evaluation of Marginal Adaptation of MTA, Biodentine, and MTA Plus as Root-End Filling Materials—An SEM Study

Abstract Objective This study aimed to evaluate adaptation of mineral trioxide aggregate (MTA), Biodentine, and MTA Plus when used as root-end restorative materials using scanning electron microscope. Materials and Methods Forty-five extracted teeth with one root canal were cleaned and sectioned at cementoenamel junction, maintaining a standardized length of 15 mm. Chemomechanical preparation and obturation was done in all the samples, and access was restored with glass ionomer cement (GIC). Root-end cavities were prepared in all the samples after 3-mm apical root end was resected. Forty-five samples were divided into three groups with 15 samples each. Root apices were filled with ProRoot MTA in group I, Biodentine in group II, and MTA Plus in group III. The sample teeth were sectioned for examination of gaps at the margins using scanning electron microscope. The data collected were put to statistical analysis by one-way ANOVA (analysis of variance) and post hoc tests. Results The minimum margin gap score of 2.44 μm was observed in group II (Biodentine), whereas maximum gap score of 5.63 μm was observed in group I (ProRoot MTA); 4.92 μm mean margin gap score was observed in group III (MTA Plus). Conclusion Biodentine showed least margin gap at the interface, so it can be considered as the best root-end filling material, whereas, MTA Plus can be considered as a substitute to ProRoot MTA as a root-end filling material.

Effect of Different Concentrations of Sodium Hypochlorite on Outcome of Primary Root Canal Treatment: A Randomized Controlled Trial

IntroductionThe aim of this study was to evaluate the effect of 2 different concentrations of sodium hypochlorite on healing and postoperative pain after primary endodontic treatment. MethodsOne hundred mandibular molars with pulp necrosis and chronic apical periodontitis were randomly assigned to 2 treatment groups: high-concentration (HC) 5% sodium hypochlorite and low-concentration (LC) 1% sodium hypochlorite. Root canal treatment was performed using a standardized protocol. Canals were prepared using equal volumes of respective irrigants after each instrument change. After chemomechanical preparation, the final flush was performed with 5 mL 17% EDTA solution followed by 5 mL 5% or 1% sodium hypochlorite depending on the group. All patients were asked to record the degree of pain on a visual analog scale every 24 hours for 1 week. At the second visit, canals were obturated, and the teeth were restored permanently. Clinical and radiographic evaluations were performed every 3 months for 12 months. The data collected were statistically analyzed. ResultsEighty-six teeth were available for evaluation at the 1-year follow-up. The overall healing rate observed was 76.7%. Greater healing was observed in the HC (81.4%) group compared with the LC group (72.1%), but the difference was not statistically significant (P > .05). No significant differences in pain incidence and pain scores were found between the 2 groups (P >.05), with lower values reported in the LC group. ConclusionsThe use of LC or HC sodium hypochlorite did not result in a significant difference in the clinical outcome.

Application of XP-Endo finisher files in the reduction of microbial load in oval-shaped root canals - An ex vivo study

The present study evaluated the effectiveness of XP-Endo Finisher (XPF) associated with XP-Endo Shaper (XPS) or Reciproc Blue (RB) files in the reduction of Enterococcus faecalis in oval-shaped root canals. Eighty mandibular incisors with single oval-shaped root canals were contaminated with E. faecalis for 10 days at 37°C with centrifugation on alternate days. The teeth were randomly assigned to eight experimental groups (n=10) as follows: G1 – XP-Endo Shaper, G2 – XP-Endo Shaper + XP-Endo Finisher, G3 – Reciproc Blue, and G4 – Reciproc Blue + XP-Endo Finisher. Chemomechanical preparation was performed with saline solution (NaCl) or 2.5% sodium hypochlorite (NaOCl). Microbial reduction was assessed by colony forming units (CFU/mL) count before (S1) and after (S2) CMP by using sterile paper points. ANOVA, Tukey’s test and Bonferroni’s post-hoc tests were used at 5% significance level. Bacteria were present in all initial samples (P&gt;.05). All instrumentation techniques reduced bacteria, irrespective of the irrigating solution (P&lt;.05). With the use of NaCl, Reciproc Blue was more effective than XP-Endo Shaper (P=.035). The association of XP-Endo Finisher improved the cleaning efficacy of both systems (P=.239). With the use of NaOCl, XP-Endo Shaper and Reciproc Blue presented similar effectiveness (P=.779). XP-Endo Finisher enhanced the bacterial reduction of both systems tested (P&lt;.05). The use of NaOCl improved the CMP, irrespective of the instrumentation technique used (P&lt;.05).

Effectiveness of XP-Endo Finisher in the reduction of bacterial load in oval-shaped root canals.

This study investigated the effectiveness of XP-Endo Finisher (XPF) associated with XP-Endo Shaper (XPS) or Reciproc Blue (RB) files in reducing bacterial load in oval-shaped root canals (RC) during chemomechanical preparation (CMP) using 0.9% saline solution (NaCl) or 2.5% sodium hypochlorite (NaOCl). Eighty mandibular incisors with single oval-shaped RC were contaminated with Enterococcus faecalis. The teeth were randomly assigned to eight experimental groups (n = 10) according to the CMP, as follows: G1: XPS, G2: XPS + XPF, G3: RB, and G4: RB + XPF. CMP was performed with NaCl or NaOCl. The reduction of bacterial load was assessed by colony-forming unit count before (S1) and after (S2) CMP. Data normality was verified by using Shapiro-Wilk test. ANOVA, Tukey's test, and Bonferroni post-hoc test were used at a 5% significance level. Culturable bacteria were present in all S1 samples (p>0.05). All instrumentation techniques were effective in reducing bacterial load, irrespective of the irrigating solution (p < 0.05). With the use of NaCl, RB was more effective than XPS (p = 0.035). With the use of NaOCl, XPS and RB presented similar effectiveness (p = 0.779). XPF enhanced the bacterial reduction of both systems tested (p < 0.05). The use of NaOCl improved the CMP, irrespective of the instrumentation technique used (p < 0.05). In conclusion, XPS and RB files are effective in reducing bacterial levels in oval-shaped RC. The use of XPF as a method of agitation of the irrigating solution improved the cleaning efficiency of both file systems tested. Mechanical preparation performed with saline solution decreased culturable bacteria from the root canal, but antimicrobial substances such as NaOCl should be used to achieve a significantly better disinfection.

Pattern of Disinfection of Root Canal Dentin by Alternated Acid-Base Irrigating Regimen.

Objective To quantify Enterococcus faecalis density in root canal dentin after chemomechanical preparation (CMP) using alternated irrigating regimen. Methodology Root canals (RC) were contaminated with E. faecalis (ATCC 19433) for 3 weeks and evident biofilms were obtained. After initial sampling (S1), the CMP was aided by irrigants: saline solution (control; n=12), a conventional regimen (CR) (group 1; n=12) using 5.25% NaOCl and a final rinse with 17% EDTA, and an alternating regimen (AR) of intercalated use of NaOCl and EDTA (group 2, n=12), followed by a second sampling (S2). After 2 weeks, S3 was obtained. Two roots were analyzed by scanning electron microscopy. Each root was divided into cervical, mild, and apical segments and sampling of the superficial (n=90) and deep (n=90) dentin layers was obtained using Gates-Glidden burs. The E. faecalis density (CFU/mg) in log10 was categorized as residual (0 > 0.2), moderate (0.2 ≥ 0.5), or elevated (> 0.5). The prevalence of positive samples in BHI and BHI-A was analyzed by Pearson's chi-square test. The data were normalized by a log10 transformation of CFU and were analyzed by one-way ANOVA and Tukey's tests. Results Biofilms were observed only in the control root canal walls. Topographically, the controls and CR showed similar distributions of E. faecalis in the dentin. Microbiologically positive root canals harbored much E. faecalis in the adjacent dentin (p < 0.05). Irrigating saline provided moderate density of E. faecalis in the dentin while CR and AR resulted in a residual density of microorganisms (p < 0.05). Conclusions The Enterococcus faecalis density in dentin was influenced by the irrigating regimen and the microbiological status of the root canal. The CMP aided by the alternating regimen interfered with the recolonization of the root canal and topographic distribution of Enterococcus in root dentin.

Shaping Ability of Two-shape and ProTaper Gold Files by using Cone-beam Computed Tomography

T-Wire and rotating motion of two-shape (2S), M-wire and rotating motion of ProTaper Gold (PG) are the recent innovations of Nickle Titanium (NiTi) rotary file system by means of thermal treatment. Therefore, a study was planned to assess the shaping ability of 2 Shape and ProTaper Gold using cone beam computed tomography (CBCT) Materials and methods: Thirty freshly extracted mandibular first molars were selected, and Pre-instrumentation CBCT imaging was performed to attain mesial and distal dentin wall measurements followed by chemo-mechanical preparation using the following NiTi files: 2S and ProTaper Gold. Post instrumentation CBCT imaging was performed for evaluation of the volume of removed dentin, apical transportation, and centering ratio. Statistical analysis was confirmed by a suitable analysis test with significance set at 0.05r. In terms of the total volume of removed dentin, apical transportation, and centering ratio there was a significant difference noted between the tow-shape and ProTaper Gold. 2Shape performed better in all aspects compared to ProTaper Gold. Two-shape (2S) maintained better original canal anatomy and volume of removed dentin was also less during chemo-mechanical preparation when compared to ProTaper Gold. Two-shape (2S) system when used clinically in patients may perform better and produce less canal transportation and canal preparation will be more centered as compared to the ProTaper Gold system.

Evaluation of Antibacterial Effect of a new root canal irrigating Formula of Salvadora persica Roots Nanoparticles. An In vitro Study

Aim: The study was done to evaluate the antibacterial effect of a new formula of Salvadora persica roots Nanoparticles as compared to sodium hypochlorite irrigating solution. Methods: A total of 20 recently extracted single-rooted, with single root canal were selected to be used in the study. Decapitation of the selected teeth for 18 mm length standardization was done. The root canals were initially instrumented using manual instrumentation till reach file size 25 for apical preparation. Sterilization of the samples was done using gamma rays. Following sterilization, the samples were divided into two groups (n=10) according to the tested irrigating solution used as follow; Group H: For Salvadora persica roots nanoparticles. Group S: For 2% sodium hypochlorite. The chemo-mechanical preparation was accomplished using Revo-S rotary system in a crown-down technique with the file sequence that was recommended by the manufacturers. Pre and post-irrigation counting of the E. Fecalis was done by determining the Colony Forming Unit. Results: The highest mean value of percentage changes in bacterial reduction was found in (Group S) (95.99%) and the least bacterial reduction percentage was found in (Group H) (82.83% with no statistically significant difference between both groups (P-value=0.068). Conclusion: Under the condition of this study, the new formula of Salvadora persica roots nanoparticles is a promising irrigating solution of herbal origin instead of the synthetic irrigating solution.

An in vitro Comparative Evaluation of Volume of Removed Dentin, Canal Transportation, and Centering Ratio of 2Shape, WaveOne Gold, and ProTaper Gold Files Using Cone-Beam Computed Tomography.

Objectives:The aim of this study was to compare the shaping ability of three file systems – 2Shape (2S), WaveOne Gold (WOG), and ProTaper Gold – using cone-beam computed tomography (CBCT).Materials and Methods:Forty-five freshly extracted mandibular teeth were chosen and instrumented using the following brands of NiTi files: 2S, WOG, and ProTaper Gold. Pre- and post-instrumentation CBCT imaging was performed to measure mesial and distal distance of the dentin walls and calculate the volume of removed dentin, apical transportation, and centering ratio. A statistical analysis of the data was performed using independent t-test. Statistical significance was set at 5%.Results:There were no significant differences between the 2S and WOG in terms of the total volume of removed dentin, apical transportation, and centering ratio, whereas ProTaper showed a greater significant difference when compared to 2S and WOG.Conclusion:Both 2S and WOG maintained the original canal anatomy better and did not remove excess dentin while chemomechanical preparation as compared to ProTaper Gold. Instruments that use rotary movement achieved an effect similar to that of the reciprocating instruments in relation to change in angle. 2S which is a two-file system and WOG which is a single-file system might perform better clinically and might show enhanced shaping ability with less canal transportation and more centered preparation when compared to ProTaper Gold that is a multiple file-system.

The Effects of Different Agitation Techniques of Canal Irrigant on Tubular Penetration of a Bioceramic Sealer.

This study aimed to compare the effects of different agitation techniques of sodium hypochlorite (NaOCL) as the final irrigation with XP-Finisher file, passive ultrasonic irrigation (PUI), Er:YAG laser and irrigation with conventional syringes, on penetration of Sure Seal Root bioceramic sealer into dentinal tubules. Forty freshly extracted single-rooted human teeth were included in the present in vitro study. All the teeth were prepared up to #40 (4%) with Bio Race rotary file system, using crown-down technique. After chemomechanical preparation, the teeth were randomly assigned to 4 groups based on the agitation protocol: conventional needle irrigation (CNI) with a 30-G needle in a syringe, PUI, Er:YAG laser and XP-Finisher file, Subsequent to the agitation procedure, the root canals were obturated with tapered bioceramic-covered gutta-percha point and, bioceramic sealer, using the single-cone technique. The maximum penetration of the sealer into the dentinal tubules was determined in the coronal, middle and apical thirds using the scanning electron microscope (SEM) technique. After confirmation of the normal distribution of data with Shapiro-Wilk test, Data were analyzed using the one-way ANOVA and Tukey tests. The mean penetration depth of the bioceramic sealer into the dentinal tubules in the PUI group was greater than that of other groups; however, the difference between the two PUI and Er:YAG laser groups in the apical third was not significant (P=0.078). Er:YAG laser, PUI and XP-Finisher file agitation techniques resulted in significantly greater penetration of the bioceramic sealer into the dentinal tubules compared to the CNI (P<0.001). The XP-Finisher file technique in the apical (P=0.752) and middle thirds (P=0.339) and the Er:YAG laser technique in the apical thirds (P=0.086) were not significantly different from the conventional irrigation technique. The PUI technique resulted in significantly deeper penetration of the Bioceramic sealer into the dentinal tubules compared to the three other techniques.

In vitro assessment of interaction between lidocaine hydrochloride and sodium hypochlorite on root canal dentin before and after chemomechanical instrumentation procedures.

Introduction:To investigate the effect of resultant precipitate formed on interaction between 2% lidocaine hydrochloride with adrenaline (LA) and 2.5% sodium hypochlorite (NaOCl) on root canal dentin before and after chemomechanical preparation, using scanning electron microscopy (SEM).Methods:Sixty mandibular premolars were decoronated, and the root length was standardized. All specimens were randomly distributed into the following three groups: Group I (control): 2% LA mixed with sterile water without root canal instrumentation, Group II: 2% LA with 2.5% NaOCl and no instrumentation, and Group III: 2% LA with 2.5% NaOCl, followed by mechanical instrumentation with rotary files. Teeth samples were sectioned into three parts, split and SEM analysis of the root canal wall was done at cervical, middle, and apical root thirds.Results:SEM images revealed patent dentinal tubules with no precipitate occlusion in the control group, whereas there was occlusion of dentinal tubules with a precipitate in all the specimens in Group II and Group III at all the three root levels studied.Conclusions:The precipitate formed on the interaction between 2% LA solution and 2.5% NaOCl tends to occlude the dentinal tubules at the coronal, middle, and apical root thirds. The chemomechanical rotary instrumentation procedure did not effectively remove the precipitate from all the three levels of the root specimens studied. LA/sterile water group did not result in any precipitate formation on root canal dentin.

Comparative evaluation of push-out bond strength of root-end filling materials in root-end cavities prepared by laser or ultrasonic technique: An in vitro study.

Context:The use of mineral trioxide aggregate (MTA) and Biodentine as a root-end filling materials used in the root-end cavities prepared by laser or ultrasonic technique is a current topic in the branch of dentistry and push-out bond strength is used to measure the adhesiveness provided by the root-end filling materials.Aim:The aim of this study is to evaluate the push-out bond strength of MTA and Biodentine in root-end cavities prepared by erbium:yttrium-aluminium-garne (Er:YAG) laser and ultrasonic retrotip.Materials and Methods:A total of 40 extracted maxillary central incisors and canines were selected. Chemomechanical preparation and obturation were done. Root-end resections were performed followed by the root-end cavity preparation and root-end filling. Specimens were divided into four groups. Root-end cavities prepared by Er:YAG laser and filled with MTA, root-end cavities prepared by Er:YAG laser and filled with Biodentine, root-end cavities prepared by ultrasonic retrotip and filled with MTA and root-end cavities prepared by ultrasonic retrotip and filled with Biodentine, respectively. The apical end was again sectioned perpendicular to the long axis. The push-out bond strength was evaluated using a universal testing machine.Statistical Analysis Used:The data were analyzed using the analysis of variance and post hoc Tukey test.Results:Difference between push-out bond strength of root-end filling materials to root-end cavity walls prepared by laser and ultrasonic retrotips was statistically nonsignificant. Push-out bond strength of MTA and Biodentine did not differ significantly.Conclusion:Difference between push-out bond strength of MTA and Biodentine to root-end cavity walls prepared by Er:YAG Laser or ultrasonic retrotip were statistically nonsignificant.

Evaluation of the antibacterial effect of three irrigant solutions in treatment of root canals of primary anterior teeth

Purpose: To evaluate and compare the antibacterial effect of 0.5%Metronidazole, 2%Chlorhexidin e, and Normal saline irrigant solutions against Enterococcus Faecalis bacteria in treatment of root canals of primary anterior teeth. Materials and methods: This in-vivo study was carried out on Sixty, anterior, primary teeth of children ranging from three to five years of age. The teeth were equally divided into three groups (20 teeth each), based on the irrigant used during chemo mechanical preparation of the root canals. Result: There was no significance difference between the action of 2.0% Chlorhexidine and 0.5% Metronidazole against Enterococcus faecalis while there was a significant difference when they were compared with the action of normal saline. Conclusion: Both 0.5%Metronidazole and 2.0%Chlorhexidine appeared to be superior as final endodontic irrigants with higher antibacterial efficacy compared to saline.

Comparative Evaluation of Depth of Penetration of Root Canal Irrigant After Using Manual, Passive Ultrasonic, and Diode Laser-Assisted Irrigant Activation Technique.

AIM:The aim of this study was to compare and evaluate the penetration depth of irrigant after using manual, passive ultrasonic, and diode laser–assisted irrigant activation technique.Materials and Methods:Ninety extracted single-rooted human mandibular premolars were selected (N = 90). Teeth were decoronated and working length was standardized for 12 mm. Root canals were shaped using ProTaper Universal F3. Saline was used as an irrigant in between every successful instrumentation. After completion of chemomechanical preparation, root canals were filled with Rhodamine-B-labeled sodium hypochlorite (3%). Teeth samples were divided into three experimental groups. In Group 1 (n = 30), manual irrigant activation was performed for 30 seconds with master cone gutta-percha (F3) in gentle up and down motion. In Group 2 (n = 30), ultrasonic irrigant activation was performed using passive ultrasonic endo tips for 30 seconds. In Group 3 (n = 30), laser activation was performed using diode laser for 30 seconds with 200-µm tips. Transverse sections were made at 2, 5, and 8 mm from the root apex and were observed under confocal laser scanning microscopy. Maximum penetration depth of irrigant was recorded and statistically analyzed.Result:In the all three groups, coronal third (sections at 8 mm from root apex) showed the highest penetration depth of irrigant. Laser activation (Group 3) showed the highest penetration depth in all the three sections when compared with manual and passive ultrasonic irrigant activation. One-way analysis of variance and post hoc test showed there were significantly high differences among all the three groups and also at all three levels (P < 0.05).Conclusion:Diode laser–assisted irrigant activation technique had better penetration depth in all the three aspects of root dentin.

Comparative Evaluation of Extrusion of Apical Debris in Primary Anterior Teeth using Two Different Rotary Systems and Hand Files

Background:The success of endodontic treatment depends on the chemomechanical preparation of the tooth. However, the debris produced during canal preparation may extrude through the apical foramen causing postoperative complications.Aim:The aim of this study is to compare the apical debris extrusion during root canal preparation in primary anterior teeth using hand files, rotary ProTaper files, and rotary Kedo-S files.Materials and Methods:Forty-five freshly extracted primary canine with mature apices and a single canal were randomly divided into three groups for instrumentation as follows (n = 15): Group 1: hand files; Group 2: rotary ProTaper files; and Group 3: rotary Kedo-S files. Myers and Montgomery experimental model was used for this study. Apically extruded debris collected in a preweighed Eppendorf tubes was placed in the incubator at 70°C for 5 days. The weight of the debris collected was determined by subtracting the pre- and post-instrumentation weight of the Eppendorf tubes. The data collected were analyzed using the analysis of variance and Tukey's post-hoc tests.Results:Hand files produced more apical debris extrusion than ProTaper and Kedo-S files (P < 0.05) while Kedo-S produced the least (P < 0.05).Conclusion:All instrumentation systems cause apical debris extrusion. Kedo-S produced less apical debris extrusion when compared to the hand files and ProTaper files.

Management of merged external/internal root resorption using CEM cement: a case report.

Chronic pulpal inflammation and infection are the main predisposing factors for internal and external root resorption (IRR &amp; ERR); however, merging of IRR and ERR is a rare lesion which rigorously alters the anatomy of root canals. This study reports a case of merged IRR and ERR in an asymptomatic maxillary left central incisor in a 33-year old Caucasian woman that was managed by one-visit root canal therapy (RCT) using calcium-enriched mixture (CEM) cement. Radiographic examination showed a short root with under-filled root canal obturation associated with ERR/IRR and an apical lesion. After thorough chemo-mechanical preparation, the root canal was obturated with CEM cement; one week later, the access cavity was permanently restored. Clinical/radiographic examinations at 1-year follow-up revealed uneventful healing, reestablishment of lamina dura and stabilization of the resorptive defects. The treatment outcome demonstrates that one-visit RCT using CEM cement may be a viable treatment option in cases with merged external/internal root resorption. Further clinical trials with a larger number of cases are suggested to document a higher level of evidence.

Effectiveness of calcium hydroxide-based intracanal medication on infectious/inflammatory contents in teeth with post-treatment apical periodontitis

The objective of this work was to investigate in vivo the effects of calcium hydroxide-based intracanal medication (ICM) on the levels of bacteria, pro-inflammatory cytokines (PICs), and matrix metalloproteinases (MMPs) in root canals and periradicular tissues of teeth with failure of the root canal treatment and apical periodontitis. Twenty infected root canals of single-rooted teeth were randomly assigned into two groups according to the irrigant used for chemomechanical preparation (CMP) (n= 10 per group): G1-2% chlorhexidine (CHX) gel and G2-6% sodium hypochlorite (NaOCl). Root canal contents were taken by using paper points before CMP (S1) and after 30days of calcium hydroxide-based ICM (S2). Microbial reduction was calculated by means of colony-forming unit count (CFU/mL), with PICs and MMPs (pg/mL) being measured by using enzyme-linked immunosorbent assay (ELISA). Culturable bacteria (101.2 ± 79.2), PICs (IL-1β 1.2 ± 0.4 and TNF-α 8.8 ± 4.7), MMP-2 (803.7 ± 96.4), MMP-3 (453.9 ± 229.3), MMP-8 (245.9 ± 122.4), MMP-9 (129.4 ± 29.6), and MMP-13 (70.8 ± 12.8) were present in all S1 samples. After 30days of ICM (S2), a 99.5% microbial reduction was observed, together with a significant reduction of PICs in all groups. Overall, it was observed a decrease in the levels of MMPs (S2), except MMP-13, which was found in increased levels after ICM (P< .05), independently of the groups. Calcium hydroxide-based intracanal medications have had a positive effect on the microbial reduction by decreasing the levels of PICs and MMPs. Both auxiliary chemical substances (i.e., 2% CHX and 6% NaOCl) presented similar effects when calcium hydroxide was used as intracanal medication. Teeth with failure of the root canal treatment and apical periodontitis, and consequently with high levels of bacteria, PIC, and MMP, may present a better prognosis after a 30days of a calcium hydroxide-based ICM.

Unprepared root canal surface areas: causes, clinical implications, and therapeutic strategies.

Chemomechanical preparation is intended to clean, disinfect, and shape the root canal. This step is of utmost importance during treatment of infected teeth with apical periodontitis, because treatment outcome depends on how effectively the clinician eliminates bacteria, their products, and necrotic tissue that would serve as substrate for bacterial regrowth. Nonetheless, curvatures and complex internal anatomical variations of the root canal system can pose a high degree of difficulty in reaching these goals. In infected teeth, bacteria may persist not only in difficult-to-reach areas such as isthmuses, ramifications, dentinal tubules, and recesses from C-shaped or oval/flattened canals, but also in areas of the main canal wall that remain untouched by instruments. If bacteria withstand chemomechanical procedures, there is an augmented risk for post-treatment apical periodontitis. This article discloses the reasons why some areas remain unprepared by instruments and discusses strategies to circumvent this issue and enhance infection control during endodontic treatment/retreatment of teeth with apical periodontitis.

Quantification by SIFT-MS of volatile compounds produced by the action of sodium hypochlorite on a model system of infected root canal content.

Root canal irrigation with sodium hypochlorite (NaOCl) is an indispensable part of the chemomechanical preparation of infected root canals in Endodontology. However, there is limited information on the emergence of toxic or hazardous volatile compounds (VOCs) from the interaction of NaOCl with the infected content of tooth biomaterials. The aim of this study was to assess the formation of VOCs and disinfection by-products (DBPs) following the interaction of NaOCl 2.5% v/v with a model system of different sources of natural organic matter (NOM) present in infected root canals, including dentine powder, planktonic multi-microbial suspensions (Propionibacterium acnes, Staphylococcus epidermidis, Actinomyces radicidentis, Streptococcus mitis and Enterococcus faecalis strain OMGS3202), bovine serum albumin 4%w/v and their combination. NaOCl was obtained from a stock solution with iodometric titration. Ultrapure water served as negative control. Samples were stirred at 37°C in aerobic and anaerobic conditions for 30min to approximate a clinically realistic time. Centrifugation was performed and the supernatants were collected and stored at -800 C until analysis. The reaction products were analysed in real time by selected ion flow tube mass spectrometry (SIFT-MS) in triplicates. SIFT-MS analysis showed that the released VOCs included chlorinated hydrocarbons, particularly chloroform, together with unexpected higher levels of some nitrogenous compounds, especially acetonitrile. No difference was observed between aerobic and anaerobic conditions. The chemical interaction of NaOCl with NOM resulted in the formation of toxic chlorinated VOCs and DBPs. SIFT-MS analysis proved to be an effective analytical method. The risks from the rise of toxic compounds require further consideration in dentistry.