Effects of ultrasonics and trephine burs on dentinal microcrack formation during broken instrument removal procedures: A micro-CT analysis.

The objective of this study was to compare the effects of ultrasonic and trephine burs on microcrack formation during the removal of broken instruments, utilising micro-computed tomography (Micro-CT). Twenty-five extracted human mandibular molars were used for this study. The hand files were fractured into the mesiobuccal canal, except in the control group. In the ultrasonic group (n = 10), ultrasonic tips were used to retrieve the instrument, while in the trephine group (n = 10), trephine burs (Meitrac, Meisinger) and an extractor device were utilised. For the control group (n = 5), only staging platform was prepared. After the removal procedures, micro-CT images were obtained from the specimens. The chi-squared test was used to analyse the data, and significance was considered to be p < 0.05. Overall, 15 736 cross sections were analysed. No significant differences were found between control and experimental groups. Removal of broken instruments with trephine burs caused significantly more dentinal microcracks compared with ultrasonics (p = 0.016).

Outcome of single-visit root canal treatment with or without MTAD: A randomized controlled clinical trial.

AIM: This study aimed to investigate 2-year changes in periapical trabecular patterns in single-rooted teeth with apical periodontitis using fractal analysis and periapical index (PAI) after root canal treatment performed with or without BioPure MTAD solution. METHODOLOGY: In this randomized clinical trial, 100 patients were selected and randomized to either the BioPure MTAD or the control groups. Initial periapical radiographs were obtained for each participant before and 2 years after root canal treatment. The region of interest in the periapical lesion around the root apex was selected from the paired periapical radiographs, and then, the fractal dimension (FD) was calculated. With regards to the classification of periapical status, PAI was labelled as "healed" (PAI ≤ 2) or "unhealed" (PAI ≥ 3). RESULTS: After 24 months, 28 patients did not comply with the follow-up and the data of 72 patients were compared. When the initial and the follow-up PAI scores were compared, the decrease was statistically significant in 33 of 37 teeth (89.2%) and 32 of 35 teeth (91.4%) in the BioPure MTAD and control group, respectively. In both groups, statistically significant increases were observed in FD values after 2 years in all patients (p < .001). No significant difference was found between the two groups amongst decreased PAI scores and increased FD values. CONCLUSIONS: Root canal treatments with or without BioPure MTAD irrigation contributed to periapical healing in single-visit root canal treatment. Two years after root canal treatment, the extent of the periapical trabecular bone radiographically increased, as the FD and PAI data revealed.

Effect of QMix as final irrigation protocol on periapical healing after single-visit root canal treatment: A randomised controlled clinical trial.

The aim of this study was to evaluate radiographic periapical repair after endodontic treatment using QMix or NaOCl irrigation in single-rooted teeth with apical periodontitis. In this randomised clinical trial, 60 patients were selected and randomised into two groups (n = 30). After instrumentation of root canals, QMix or NaOCl was used as a final irrigation and the canals obturated with gutta-percha and AH Plus sealer. All the participants were recalled after 12 months and 15 patients were lost to the study so 45 patients were evaluated radiographically according to periapical index (PAI) scores. A significant decrease was seen in PAI scores after 1 year in all patients (p < 0.001). In the QMix and NaOCl group, absence or reduction of radiolucency was observed in 23 of 25 teeth (92%) and 20 of 20 teeth (100%), respectively. There was no significant difference between two groups according to the decrease in PAI score (p = 0.508). Root canal treatments with or without QMix irrigation contributed equally to periapical healing.

Calcium hypochlorite on mouse embryonic fibroblast cells (NIH3T3) in vitro cytotoxicity and genotoxicity: MTT and comet assay.

Antimicrobial irrigation solutions are widely used under clinical settings. Their effect on dental tissue is a subject of recent research, which aims for a safer irrigant for clinical use. In this regard, here our goal was to evaluate the cytotoxicity and the genotoxicity of calcium hypochlorite (Ca(OCl)2) solution, along with NaOCl, on Mouse embryonic fibroblast cells (NIH3T3). First, Cells were treated either with NaOCl or Ca(OCl)2 in a time- and dose-dependent manner for cytotoxicity by 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, then cell viability was calculated according to cell proliferation plots. Secondly, genotoxicity was assessed by Comet assay. Data were statistically analyzed by Tukey's test (P < .05). NaOCl and Ca(OCl)2 had similar effects on cellular viability at 3 and 6 h treatments. Cell viability of Ca(OCl)2 at concentrations of 0.0125%, 0.025%, 0.05%, or 0.125% was significantly lower than that of NaOCl at 24 h treatment (P < .05).Comparing Ca(OCl)2 and NaOCl treatments at all time points and concentrations, the damaged cell number of Ca(OCl)2 was almost fourfold higher than that of NaOCl. In conclusion, both, NaOCl and Ca(OCl)2 solutions were cytotoxic and genotoxic to NIH3T3, however, Ca(OCl)2 had a significantly higher damaged cell percentage than NaOCl at all time points and concentrations investigated.

Effects of MTAD on the bond strength of bioceramic root canal sealer

Aim: The aim of this in-vitro study was to investigate the effects of MTAD (a mixture of doxycycline, citric acid, and a detergent) on the bond strength of AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany) and EndoSequence BC sealer (Brasseler USA, Savannah, Georgia, USA). Materials & Methods: Eighty-four decoronated single-rooted human incisor teeth were prepared with Reciproc R25 files (VDW, Munich, Germany), and the canal was irrigated with 5 mL 1.3% NaOCl. The roots were randomly assigned to four groups (n = 21), according to the final irrigation protocol and sealer selection: Group 1: distilled water-AH Plus; Group 2: distilled water-EndoSequence BC; Group 3: MTAD-AH Plus; Group 4: MTAD-EndoSequence BC. For the final flush, in Groups 1 and 2, the root canals were irrigated with 5mL of distilled water; in Groups 3 and 4, 5mL of MTAD was used for 1 minute. After root canal obturation, specimens was embedded in an acrylic block and sectioned horizontally at three levels (coronal, middle, apical). Bond strength of sealer to root canal dentin was assessed via push-out test using a universal testing machine. Results: There were no significant differences among the groups in coronal and apical thirds. In the middle root third, Group 4 showed significantly lower push-out bond strength values than Group 2 (p=0.023). No significant difference was found between the two root canal sealers. Conclusions: Overall, MTAD final irrigation caused lower push-out bond strenght values than distilled water with no significancy.

Post-obturation pain following the use of carrier-based system with AH Plus or iRoot SP sealers: a randomized controlled clinical trial.

OBJECTIVES: The aim of this study was to compare the postoperative pain after root canal treatment using a carrier-based obturation system and two different sealers. MATERIALS AND METHODS: In this prospective randomized clinical trial, 160 patients were selected. Patients with vital and devital teeth were randomized into four groups using a randomized block design with block sizes of 10 patients each. The groups were devital/vital teeth treated with iRoot SP sealer and devital/vital teeth treated with AH Plus sealer. Patients were prescribed ibuprofen, a 200-mg analgesic, if needed, and postoperative pain was recorded by visual analogue scale at 6, 12, 24, and 72 h after obturation. Pain score and frequency of tablet intake were recorded and statistically analyzed. RESULTS: Results showed that there was no significant difference between groups in the incidence of postoperative pain; however, iRoot SP sealer was associated with less analgesic intake compared to AH Plus sealer. CONCLUSION: The use of different sealers did not significantly affect pain levels. CLINICAL RELEVANCE: iRoot SP sealer was associated with less analgesic intake compared to AH Plus sealer.

Effect of irrigation technique for removal of triple antibiotic paste on bond strength of MTA to root dentin.

This study evaluated the bond strength of mineral trioxide aggregate (MTA) to root canal dentin after the performance of various irrigation procedures to remove triple antibiotic paste (TAP). A total of 56 single-rooted human mandibular premolars were instrumented using a rotary system to size 40 and divided randomly into a control group (no intracanal dressing) and three experimental groups (TAP application for 28 days). TAP was then removed by rinsing with 10 mL 2.5% NaOCl using three irrigation systems (Vibringe sonic irrigation, CanalBrush, and syringe irrigation). The coronal and middle parts of root canals were then obturated with MTA. After storage for 1 week, each specimen was embedded in an acrylic block and sectioned horizontally (2-mm-thick slices) at two levels (coronal and middle). Bond strength of MTA to root canal dentin was assessed in 28 samples per group via push-out test using a universal testing machine. Data from the four groups were compared using one-way analysis of variance. Tukey's test was used for multiple comparisons. Push-out bond strength values were significantly higher in the control and Vibringe groups than in the CanalBrush and syringe irrigation groups (p < 0.001). TAP removal from root canals with the Vibringe irrigation system may increase the push-out bond strength of MTA compared with the use of the CanalBrush or syringe irrigation.

Antibacterial Efficacy of Calcium Hypochlorite with Vibringe Sonic Irrigation System on Enterococcus faecalis: An In Vitro Study.

Aim. The purpose of this study was to compare the in vitro efficacy of calcium hypochlorite (Ca[OCl]2) and sodium hypochlorite (NaOCl) associated with sonic (Vibringe) irrigation system in root canals which were contaminated with Enterococcus faecalis. Material and Methods. The root canals of 84 single-rooted premolars were enlarged up to a file 40, autoclaved, inoculated with Enterococcus faecalis, and incubated for 21 days. The samples were divided into 7 groups according to the irrigation protocol: G0: no treatment; G1: distilled water; G2: 2.5% NaOCl; G3: 2.5% Ca(OCl)2; G4: distilled water with sonic activation; G5: 2.5% NaOCl with sonic activation; and G6: 2.5% Ca(OCl)2 with sonic activation. Before and after decontamination procedures microbiological samples were collected and the colony-forming units were counted and the percentages of reduction were calculated. Results. Distilled water with syringe irrigation and sonic activation groups demonstrated poor antibacterial effect on Enterococcus faecalis compared to other experimental groups (p < 0.05). There was no statistically significant difference between syringe and sonic irrigation systems with Ca(OCl)2 and NaOCl. Conclusion. The antimicrobial property of Ca(OCl)2 has been investigated and compared with that of NaOCl. Both conventional syringe irrigation and sonic irrigation were found effective at removing E. faecalis from the root canal of extracted human teeth.

The effect of antibiotic pastes on microhardness of dentin.

AIM: The aim of this study was to evaluate the effect of various endodontic regeneration agents on the microhardness of human root dentin after contact for various time intervals. MATERIALS AND METHODS: Thirty-five extracted human maxillary incisors were selected. The canals were enlarged and fixed in acrylic resin blocks. Two sections were obtained from the middle-third of each root (n = 70). The root discs were divided randomly into three groups of 20 and a control group of 10. Baseline microhardness testing was completed using a microhardness tester. The root discs were placed in Petri dishes and then assigned randomly to triple antibiotic paste (TAP), double antibiotic paste (DAP), calcium hydroxide paste (CH) and the control group. The CH and two antibiotic pastes were placed in the Petri dishes, and the discs were covered completely with the mixtures. Microhardness tests were repeated in the same manner after weeks 1, 2 and 3. Data were analysed statistically with a chi-square and Fisher's exact test at the 5% significance level and post hoc analysis was performed. RESULTS: No significant change in dentin microhardness occurred in the control group (P > 0.05). Overall, the dentin microhardness values decreased after treatment with the CH and antibiotic pastes over all time intervals. The DAP group showed reduced Knoop hardness number (KHN) values compared with the TAP group at the 1 measurements (P < 0.01). Statistically significant differences were found among the control, DAP and TAP groups, but no difference was seen between the control and CH groups at the week 1 measurement. No significant difference was found between the DAP and TAP groups at the week 4 measurement. CONCLUSIONS: Applying DAP and TAP for 4 weeks significantly reduced the microhardness values of dentin discs compared with the baseline values.

Effect of irrigation technique for removal of triple antibiotic paste on bond strength of MTA to root dentin

Abstract This study evaluated the bond strength of mineral trioxide aggregate (MTA) to root canal dentin after the performance of various irrigation procedures to remove triple antibiotic paste (TAP). A total of 56 single-rooted human mandibular premolars were instrumented using a rotary system to size 40 and divided randomly into a control group (no intracanal dressing) and three experimental groups (TAP application for 28 days). TAP was then removed by rinsing with 10 mL 2.5% NaOCl using three irrigation systems (Vibringe sonic irrigation, CanalBrush, and syringe irrigation). The coronal and middle parts of root canals were then obturated with MTA. After storage for 1 week, each specimen was embedded in an acrylic block and sectioned horizontally (2-mm-thick slices) at two levels (coronal and middle). Bond strength of MTA to root canal dentin was assessed in 28 samples per group via push-out test using a universal testing machine. Data from the four groups were compared using one-way analysis of variance. Tukey's test was used for multiple comparisons. Push-out bond strength values were significantly higher in the control and Vibringe groups than in the CanalBrush and syringe irrigation groups (p < 0.001). TAP removal from root canals with the Vibringe irrigation system may increase the push-out bond strength of MTA compared with the use of the CanalBrush or syringe irrigation.

In vitro susceptibility of e.faecalis and c.albicans isolates from apical periodontitis to common antimicrobial agents, antibiotics and antifungal medicaments.

The aim of this study was to evaluate in vitro antimicrobial activity of 4 antibiotic agents (for E.faecalis) and 4 antifungal agents (for C.albicans) by agar dilution method. Additionally, modified strip diffusion method was used for detection of in vitro antimicrobial activities of 5% NaOCl, 2.5% NaOCl, 17% EDTA and 2% CHX and agar diffusion method for detection of in vitro susceptibilities of three intracanal medicaments for 18 E.faecalis and 18 C.albicans isolates from primary and secondary root canal infection. Isolates were recovered from 231 endodontic samples of patients, with the need of root canal treatment and retreatment. All tested E.faecalis isolates showed resistance to antibiotics. For irrigation solutions, 2% CHX was more effective in eliminating E.faecalis but 5% NaOCl showed larger inhibition zone than 2.5% NaOCl, 17% EDTA and 2% CHX. For intracanal medication, Ca(OH)2-CHX worked efficiently in killing E.faecalis isolates compared to Ca(OH)2-Steril saline solution, Ca(OH)2-Glycerin. For C.albicans, 18 isolates were susceptible to amphotericin B, nistatin, fluconazole but showed resistance to ketoconazole. 5% NaOCl was more effective in eliminating and produced larger inhibition zone compared to 2.5% NaOCl, 17% EDTA and 2% CHX. Ca(OH)2-Glycerin intracanal medication was better in eliminating C.albicans isolates and produced larger inhibition zone compared to other Ca(OH)2 medicaments. Key words:E.faecalis, C.albicans, antimicrobial, antibiotic, antifungal.

Polymerase chain reaction of enterococcus faecalis and candida albicans in apical periodontitis from Turkish patients.

AIM: The aim of this study was to determine the frequency of two important pathogenic microorganisms associated with endodontic infections, Enterococcus faecalis and Candida albicans, in root canal samples from patients with necrotic pulps or failed canal therapy by polymerase chain reaction method. METHOD: Microbial samples were obtained from 117 teeth with necrotic pulp tissues and 114 teeth with failed endodontic treatment. RESULTS: E.faecalis were identified in 16% of the necrotic and 10% of the retreated root canal infections by PCR. C.albicans genome were identified in 20% and 11% of the necrotic and retreated root canal infections, respectively, by PCR. The frequencies of microbiota were not statistically different between necrotic and retreatment groups (p > 0.05, chi squared test). CONCLUSIONS: PCR analysis of teeth with periapical lesions revealed that E.faecalis was found in fewer patients than in previous studies. The C.albicans prevelance was consistent with previous reports. No statistical difference was found between primary and secondary root canal infections for C.albicans or E.faecalis. Key words:Primary root canal infection, secondary root canal infection, E.faecalis, C.albicans.

Disinfection of artificially contaminated Resilon cones with chlorhexidine and sodium hypochlorite at different time exposures.

OBJECTIVE: The aim of this study was to evaluate the efficiency of chlorhexidine (CHX) and sodium hypochlorite (NaOCl) solutions on Resilon cones that were artificially contaminated with microbial samples of Enterococcus faecalis or Candida albicans at various concentrations and time exposures. STUDY DESIGN: Resilon cones artificially contaminated with E faecalis or C albicans were left in contact with 1% NaOCl, 5% NaOCl, and 2% CHX disinfecting solutions for 1 and 5 minutes. The cones were then individually transferred to the test tubes, which contained 10 mL of thioglycollate media, and were incubated at 37 degrees C for 7 days. The antimicrobial activities of tested agents were determined by microbial growth. RESULTS: All of the Resilon cones contaminated with E faecalis or C albicans could be disinfected with 1% and 5% NaOCl for 1 and 5 minutes and with 2% CHX for 5 minutes. Three of 7 Resilon cones contaminated with E faecalis and 1 of 7 Resilon cones contaminated with C albicans could not be disinfected with 2% CHX at 1 minute of treatment. CONCLUSIONS: In conclusion, these results demonstrated that 1% and 5% NaOCl solutions are effective agents for disinfecting Resilon cones in 1- or 5-minute treatments. Two percent CHX was only effective after 5 minutes of treatment.

Effects of sodium hypochlorite and chlorhexidine solutions on Resilon (synthetic polymer based root canal filling material) cones: an atomic force microscopy study.

The aim of the present study is to evaluate the effects of 2% chlorhexidine and 5.25% sodium hypochlorite on the surface properties of Resilon cones with the atomic force microscopy. The Resilon cones were immersed in disinfecting agents (5.25% sodium hypochlorite and 2% chlorhexidine) at 1 and 5 min time intervals. Atomic force microscopy was used to evaluate topographical deviations of Resilon cones. Root mean square (RMS) parameters for topographic amplitudes were calculated. The cones exhibited statistically significant low RMS values at 5-min immersion in sodium hypochlorite and chlorhexidine groups compared to the all other groups (p < 0.05). One-minute immersion did not show any significant deterioration on the Resilon surface (p > 0.05). In conclusion, sodium hypochlorite and chlorhexidine solutions used for disinfection significantly decreased (p < 0.05) the RMS values of Resilon cones at 5-min applications.