Ex vivo comparison of antibacterial efficacy of conventional chemomechanical debridement alone and in combination with light-activated disinfection and laser irradiation against Enterococcus faecalis biofilm.

BACKGROUND AND OBJECTIVES: Intracanal disinfection plays an important role in endodontic treatment success. Enterococcus faecalis (E. faecalis) is a resistant microorganism responsible for endodontic infections. We aimed to assess the bactericidal effects of three disinfection methods on E. faecalis biofilm. MATERIALS AND METHODS: Fifty-five freshly extracted single-rooted human teeth were evaluated. A barbed broach was used to extract the pulp tissue. No further root canal preparation was performed. Specimens were sterilized with gamma radiation, and inoculated with E. faecalis suspension. They were then incubated for 4 days and 4 weeks. Biofilm formation was confirmed using a scanning electron microscope (SEM). The teeth were randomly assigned to three subgroups (n = 7) to assess the antimicrobial efficacy of the following three disinfection methods against immature (4-day) and mature (4-week) biofilms: the conventional chemomechanical debridement (CCMD), CCMD + light-activated disinfection (LAD; 810 nm, 0.3 W, 120 J/cm2) with indocyanine Green (EmunDo) as photosensitizer and CCMD + diode laser irradiation (810 nm, 2 W). The teeth were then longitudinally split into two halves and the colony count was reported as colony forming units (CFUs) to assess bacterial viability after each disinfection protocol. RESULTS: None of the disinfection methods could completely remove the biofilm. CCMD + LAD caused the highest and CCMD + diode laser caused the lowest reduction in biofilm. Antibacterial efficacy was significantly lower against the mature (4-week) biofilm compared with immature (4-day) biofilm in all groups (P < 0.05). CONCLUSION: All three disinfection methods were effective for partial elimination of E. faecalis biofilm. But CCMD + LAD was significantly more efficacious in decreasing both mature and immature biofilms.

Extraoral Sinus Tracts of Odontogenic Origin: A Case Series.

Extraoral sinus tracts of odontogenic origin often develop as the result of misdiagnosis of persistent dental infections due to trauma, caries, or periodontal disease. Due to these lesions' imitation from cutaneous lesions, misdiagnosis, and mismanagement, which we frequently encounter, this article aims to describe four cases with manifestations in different parts of the face and the neck. Patients were referred to an endodontist with a history of several surgical procedures and/or antibiotic therapy due to misdiagnosis. After comprehensive examinations, root canal treatment was performed. The resolution of signs and symptoms during the follow-up period confirmed the correct diagnosis. Dermatologists and other physicians should be aware of the possibility of the relationship of extraoral sinus tracts with dental infections. Precise examination and taking a comprehensive history can aid to prevent unnecessary and incorrect therapeutic and/or pharmaceutical interventions. Elimination of dental infection leads to complete recovery in such patients.

Evaluation of the antibacterial efficacy of various root canal disinfection methods against Enterococcus faecalis biofilm. An ex-vivo study.

BACKGROUND: Complete elimination of bacteria and their by-products from the root canal system is very difficult with current techniques. The purpose of this study was to compare the antibacterial efficacy of different disinfection protocols against Enterococcus faecalis (E. faecalis) biofilms. METHODS: Seventy-six extracted single-rooted human teeth were selected. Root canal preparation was done by proTaper rotary instruments. The smear layer was removed by 17% EDTA, followed by 5.25% sodium hypochlorite. After sterilization using gamma irradiation, sterilized specimens were inoculated with an E. faecalis suspension, incubated for 4 days and 4 weeks and then randomly divided into two experimental groups (4 days, 4 weeks old biofilms). After the confirmation of biofilm formation with SEM, the specimens in the experimental groups were randomly divided into five experimental subgroups according to the method of disinfection applied, which included: Diode laser irradiation (810 nm, 2 W), Light activated disinfection (LAD) with Indocyanine Green, 0.2% Chlorhexidine gluconate (0.2% CHX), 0.2% CHX + LAD and 0.2% CHX + Diode groups. RESULTS: Complete biofilm bacterial elimination was not observed in either of the experimental groups. CHX + LAD (0.2%) method exhibited the highest reduction value in biofilm and only Diode alone revealed the lowest in all the root canal portions. Disinfection protocols also showed significantly lower antibacterial efficacy against 4-week old than the 4-day old matured biofilms (P < 0.05). CONCLUSION: All the evaluated methods in this study were effective in the relative elimination of the E. faecalis biofilms except diode laser alone. Nevertheless, 0.2% CHX + LAD exhibited significantly higher efficacy in reducing both 4-day and 4-week old biofilms.

The Effect of Root Canal Preparation Using Single Versus Multiple Endodontic Rotary Files on Post-operative Pain, a Randomised Clinical Trial.

OBJECTIVE: The purpose of this randomised clinical trial study was to compare the incidence and intensity of post-operative pain following the use of single-file and multi-file rotary instruments with continuous rotational motion for root canal preparation in asymptomatic permanent human teeth. METHODS: A total of 105 healthy consenting patients who fulfilled specific inclusion criteria and had premolar or molar teeth diagnosed with asymptomatic irreversible pulpitis without periapical pathosis requiring endodontic treatment participated in this study. The patients were randomly allocated by stratification into five groups of 21 according to the instruments and systems used for root canal preparation: (a) Neoniti A1 (#25) single file, (b) RaCe #25/.06 single file, (c) Mtwo #25/.06 single file, (d) Easy RaCe, (e) and Mtwo multifile. Endodontic treatment was carried out in a single appointment. The severity of post-operative pain was assessed by numerical rating scale scores until complete pain relief was achieved. Analgesic consumption and the incidence of pain were also evaluated. Data were analysed by one-way ANOVA and Tukey HSD tests. RESULTS: When comparing different instruments and systems for canal preparation, the analgesic consumption, incidence and intensity of post-operative pain did not differ (p>0.05). The highest levels of post-operative pain were experienced after 6 h in all groups. CONCLUSION: The post-operative pain did not differ between the single and multi-file root canal preparation techniques evaluated in this study.

Evaluation of the Fractured Surface of Five Endodontic Rotary Instruments: A Metallurgical Study.

INTRODUCTION: The aim of this study was to compare several metallurgic properties of Neoniti instrument with four other commonly used endodontic rotary files. METHODS AND MATERIALS: Neoniti A1 (25/0.08), RaCe (25/0.06), Mtwo (25/0.06), Twisted file (25/0.06) and ProTaper Next X2 (25/0.06) were examined by differential scanning calorimetry (DSC) before and after heat treatment at 500°C. X-ray diffraction (XRD) was also performed on the specimens. Furthermore, scanning electron microscopy (SEM) and x-ray energy-dispersive spectrometric (EDS) analyses were carried out on randomly selected fractured files. RESULTS: In SEM tests, dimpled ruptures, characteristic of ductile fracture, were seen in all evaluated cross sections of all files. The SEM results of all evaluated files were alike. EDS results revealed higher proportions of Nickel (Ni) rich intermetallic compounds in Neoniti; whereas, in all the other files the proportion of Titanium (Ti) rich precipitates was higher. DSC results indicated that the temperature present in the oral environment, the austenite phase existed in all files. Mtwo and RaCe files did not show austenite transformation in the temperature range evaluated in this study. Only Neoniti revealed rhombohedal phase (R-phase) transformation. After heat treatment. No significant difference was seen in the transformation temperatures of all evaluated files. XRD evaluations revealed that Neoniti contained both Ni-rich and Ti-rich precipitates. The amount of the martensite phase was higher in ProTaper Next. CONCLUSION: The metallurgic properties of Neoniti files were different from other evaluated rotary files. This file contained higher proportions of Ni-rich precipitates.

Penetration Depth of Sodium Hypochlorite in Dentinal Tubules after Conventional Irrigation, Passive Ultrasonic Agitation and Nd:YAG Laser Activated Irrigation.

INTRODUCTION: The penetration depth of irrigating solutions in dentinal tubules is limited; consequently, bacteria can remain inside dentinal tubules after the cleaning and shaping of the root canal system. Therefore, new irrigation systems are required to increase the penetration depth of irrigating solutions in dentinal tubules. METHODS: A comparative study regarding the penetration depth of sodium hypochlorite (NaOCl) solution in dentinal tubules using four methods, (1) conventional irrigation (CI), (2) smear layer removal plus conventional irrigation (gold standard), (3) passive ultrasonic agitation (PUA) and (4) Nd:YAG laser activated irrigation (LAI), took place on 144 extracted mandibular teeth with a single root canal. After decoronation with a diamond disc and working length determination, the apical foramen was sealed with wax. The canals were prepared up to #35 Mtwo rotary file and 5.25% NaOCl was used for irrigation during preparation. To study the penetration depth of NaOCl, smear layer was eliminated in all samples. Dentinal tubules were stained with crystal violet and after longitudinal sectioning of teeth, the two halves were reassembled and root canal preparation was performed up to #40 Mtwo rotary file. Then the samples were distributed into four experimental groups. Depth of the bleached zone was evaluated by stereomicroscope (20X). Data were analyzed by Kruskal-Wallis test. RESULTS: The highest and lowest average for NaOCl penetration depth in all three coronal, middle and apical sections belonged to CI + smear layer removal and CI. A statistically significant difference was seen when comparing the penetration depth of CI + smear layer removal group to CI and PUA groups in coronal and middle third, in which the average NaOCl penetration depth of the gold standard group was higher (P < 0.05). A statistically significant difference was seen between CI + smear layer removal group and the other three groups including CI, PUA and LAI in apical third, in which the average NaOCl penetration depth in the gold standard group was higher (P < 0.001). CONCLUSION: The standard protocol for smear layer removal led to more effective smear layer elimination and deeper penetration depth of irrigation solutions. PUA and LAI groups exhibited less smear layer elimination and penetration depth of irrigation solutions. Therefore, CI+smear layer removal should still be considered as the gold standard.

Maturogenesis of Two Maxillary Central Incisors: A Case Report with 10 Years of Follow Up.

This case report describes the treatment of two immature maxillary central incisors in a 7-year-old female patient. She suffered complicated crown fracture because of trauma, and the root formation was incomplete. White mineral trioxide aggregate (MTA) was selected as the pulp-capping material after cervical pulpotomy to preserve the pulp tissue vitality and achieve maturogenesis. Follow-up evaluations showed successful treatment in terms of preservation of pulp vitality and demonstrated marked continuous physiological root development. During 10 years of follow-up, both teeth were clinically asymptomatic, and radiographic evaluations showed apparent root regeneration with apical root-end closure without pulp or periapical pathosis.

Comparison of Obturation Quality in Modified Continuous Wave Compaction, Continuous Wave Compaction, Lateral Compaction and Warm Vertical Compaction Techniques.

OBJECTIVES: The aim of this study was to introduce modified continuous wave compaction (MCWC) technique and compare its obturation quality with that of lateral compaction (LC), warm vertical compaction (WVC) and continuous wave compaction techniques (CWC). The obturation time was also compared among the four techniques. MATERIALS AND METHODS: Sixty-four single-rooted teeth with 0-5° root canal curve and 64 artificially created root canals with 15° curves in acrylic blocks were evaluated. The teeth and acrylic specimens were each divided into four subgroups of 16 for testing the obturation quality of four techniques namely LC, WVC, CWC and MCWC. Canals were prepared using the Mtwo rotary system and filled with respect to their group allocation. Obturation time was recorded. On digital radiographs, the ratio of area of voids to the total area of filled canals was calculated using the Image J software. Adaptation of the filling materials to the canal walls was assessed at three cross-sections under a stereomicroscope (X30). Data were statistically analyzed using ANOVA, Tukey's post hoc HSD test, the Kruskal Wallis test and t-test. RESULTS: No significant difference existed in adaptation of filling materials to canal walls among the four subgroups in teeth samples (P ≥ 0.139); but, in artificially created canals in acrylic blocks, the frequency of areas not adapted to the canal walls was significantly higher in LC technique compared to MCWC (P ≤ 0.02). The void areas were significantly more in the LC technique than in other techniques in teeth (P < 0.001). The longest obturation time belonged to WVC technique followed by LC, CW and MCWC techniques (P<0.05). The difference between the artificially created canals in blocks and teeth regarding the obturation time was not significant (P = 0.41). CONCLUSION: Within the limitations of this in vitro study, MCWC technique resulted in better adaptation of gutta-percha to canal walls than LC at all cross-sections with fewer voids and faster obturation time compared to other techniques.

Effect of Bacterial Lipopolysaccharide Contamination on Gutta Percha- versus Resilon-Induced Human Monocyte Cell Line Toxicity.

OBJECTIVES: Cytotoxic effects of obturation materials were tested in presence and absence of endotoxin on human monocytes in vitro. MATERIALS AND METHODS: Human monocytes from THP-1 cell line were cultured. Three millimeters from the tip of each Resilon and gutta percha points were cut and directly placed at the bottom of the culture wells. Cultured cells were exposed to gutta percha (groups G1 and G2) and Resilon (R1 and R2). Ten µg/ml bacterial lipopolysaccharide (LPS) was added to the culture wells in groups G1 and R1. Positive control included the bacterial LPS without the root canal filling material and the negative control contained the cells in culture medium only. Viability of cells was tested in all groups after 24, 48, and 72 hours using the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay for at least 3 times to obtain reproducible results. Optical density values were read and the data were analyzed using three-way ANOVA and post hoc statistical test. RESULTS: The results showed that cells in G2 had the lowest rate of viability at 24 hours, but the lowest rate of viable cells was recorded in G1 at 48 and 72 hours. The effect of LPS treatment was not statistically significant. Resilon groups showed cell viability values higher than those of gutta percha groups, although statistically non-significant (P=0.105). Cell viability values were lower in gutta percha than Resilon groups when LPS-treated and LPS-untreated groups were compared independently at each time point. CONCLUSION: It could be concluded that none of the tested root canal filling materials had toxic effects on cultured human monocyte cells whether in presence or absence of LPS contamination.

Cytotoxic Effects and Osteogenic Activity of Calcium Sulfate with and without Recombinant Human Bone Morphogenetic Protein 2 and Nano-Hydroxyapatite Adjacent to MG-63 Cell Line.

OBJECTIVES: The aim of this study was to assess the cytotoxic effects and osteogenic activity of recombinant human bone morphogenetic protein (rhBMP2) and nano-hydroxyapatite (n-HA) adjacent to MG-63 cell line. MATERIALS AND METHODS: To assess cytotoxicity, the 4,5-dimethyl thiazolyl-2,5-diphenyl tetrazolium bromide (MTT) assay was used. Alkaline phosphatase (ALP) activity and osteogenic activity were evaluated using Alizarin red and the von Kossa staining and analyzed by one-way ANOVA followed by Tukey's post hoc test. RESULTS: The n-HA/calcium sulfate (CS) mixture significantly promoted cell growth in comparison to pure CS. Moreover, addition of rhBMP2 to CS (P=0.02) and also mixing CS with n-HA led to further increase in extracellular calcium production and ALP activity (P=0.03). CONCLUSION: This in vitro study indicates that a scaffold material in combination with an osteoinductive material is effective for bone matrix formation.

An In Vitro Comparison of Marginal Adaptation of MTA and MTA-Like Materials in the Presence of PBS at One-Week and Two-Month Intervals.

OBJECTIVE: This study compared the marginal adaptation of mineral trioxide aggregate (MTA) and MTA-like materials as root-end fillings after incubation in phosphate buffer saline (PBS), a synthetic tissue fluid, for either 1 week or 2 months. MATERIALS AND METHODS: In this experimental study, seventy-two extracted human single-rooted teeth were prepared and obturated with gutta-percha and AH26 sealer. The apical 3 mm of the roots were resected. Root-end cavities were prepared with an ultrasonic retrotip. The specimens were randomly divided into three groups (n=24) and filled with either ProRoot MTA, OrthoMTA, or RetroMTA. Half of the specimens in each group were stored in PBS for 1 week the other half for 2 months. Epoxy resin replicas from the resected root-end surfaces and longitudinally sectioned roots were fabricated. The gaps at the material/dentin interface were measured using a scanning electron microscope (SEM). Transversal, longitudinal, and overall gap sizes were measured. The data were analyzed using Kruskal-Wallis and Mann-Whitney tests. The significance level was set at p < 0.05. RESULTS: There were no significant differences between the marginal adaptation of ProRoot MTA, RetroMTA, and OrthoMTA in both transverse and longitudinal sections after incubation for either 1 week or 2 months (p > 0.05). In addition, the test groups were not significantly different regarding the overall mean gap values (p > 0.05). CONCLUSION: Under the conditions of this study, there was no difference between the marginal adaptation of ProRoot MTA, OrthoMTA, and RetroMTA as root-end filling materials after exposure to PBS for either 1 week or 2 months.

The effect of Er,Cr:YSGG laser irradiation on the push-out bond strength of RealSeal self-etch sealer.

OBJECTIVE: The aim of this study was to evaluate the effect of an erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the push-out bond strength of RealSeal Self-Etch (SE) sealer. BACKGROUND DATA: Various methods are used for smear layer removal in endodontics, such as the application of Er,Cr:YSGG lasers. This laser system may influence the bond strength of resin-based sealers. METHODS: Sixty single-rooted extracted teeth were selected. After root canal preparation, samples were divided into two experimental groups and one positive control group (n=20 per group). In group 1, the smear layer was removed by irrigation with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl). In group 2, the smear layer was removed using a 2.78 µm Er,Cr:YSGG laser with radial firing tips (RFT3) (parameters: 1.5 W, 140 µs, 20 Hz, and 15% water to 15% air ratio), moving at 2 mm/sec in an apico-coronal direction. Group 3 served as a positive control group. Five specimens from each group were selected for scanning electron microscope (SEM) observation. The remaining 45 roots were obturated with RealSeal SE/Resilon and subjected to push-out tests. Data were analyzed using one way analysis of variance (ANOVA) and Tamhane's test. RESULTS: The results showed no significant difference between push-out bond strength of root canal fillings in the EDTA+NaOCl group and the 1.5 W laser group (p>0.05). The positive control group showed the lowest push-out bond strength. CONCLUSIONS: The results of the present study indicate that the application of an Er,Cr:YSGG laser with radial firing tips did not adversely affect the push-out bond strength of RealSeal SE sealer to dentin.

Evaluation of three methods in the diagnosis of dentin cracks caused by apical resection.

OBJECTIVE: To compare three various methods in the diagnosis of dentinal cracks formed in the apical third after root resection. MATERIALS AND METHODS: One hundred extracted human maxillary central incisors were selected. The root canals were prepared with step-back technique. Then 3mm from the apical end of all roots was cut perpendicular to the long axis of the tooth. The apical end of each root was evaluated to make sure there were no cracks. Fifty specimens were randomly chosen and connected to an apparatus especially designed for application of force (50-60N) by a universal testing machine for crack formation. The cracked (no=50) and non-cracked (no=50) specimens were examined by three methods of fiber optic transillumination, methylene blue staining and combination of the two. Sensitivity and specificity of the methods were evaluated. The most suitable method for detecting cracks was determined using Youden index. To compare agreement between studied methods with the gold standard, kappa statistics and odds ratio of McNemar were utilized. RESULTS: The sensitivity of transillumination, staining and the combination method were 82.0, 50.0 and 90.0%, respectively. The staining technique had the lowest sensitivity and the highest specificity. Both transillumination and the combination method had Youden index of 0.56, but the combination method diagnosed truly cracked samples more than the other techniques. CONCLUSION: The efficacy of transillumination in identification of apical root-end cracks undetectable by unaided vision was similar to the combination method. However, the efficacy of 2% methylene blue without transillumination was significantly lower than the other two methodologies.

Coronal microleakage in root canals obturated with lateral compaction, warm vertical compaction and guttaflow system.

INTRODUCTION: Root canal obturation seals the root canal system to prevent re-entry and/or growth of microorganisms. The provision of an appropriate restoration to coronally seal the access cavity affects the success of endodontic treatment. The purpose of this study was to evaluate the coronal microbial leakage in root canals that were either filled by lateral compaction, GuttaFlow or warm vertical compaction. MATERIALS AND METHODS: In this ex vivo study, 80 single-rooted human extracted teeth were randomly divided into three experimental groups (n=20) and two positive and negative control groups (n=10). The teeth in experimental groups were obturated with cold lateral compaction, GuttaFlow system or warm vertical compaction techniques. After sterilization of the whole system with gamma-ray, saliva leakage was tested using a split-chamber model. Specimens were monitored every 24 hours for 30 days. The data were analyzed using log-rank and Kaplan-Meier survival analysis tests. RESULTS: There were no significant differences in impeding saliva leakage between the three experimental groups (P>0.05). CONCLUSION: Under the conditions of this ex vivo study, it can be concluded that the sealing ability of cold lateral compaction, warm vertical compaction and GuttaFlow system was comparable.

Retreatment of a 6-canalled mandibular first molar with four mesial canals: a case report.

Successful root canal treatment requires adequate knowledge regarding morphologic variations in root canal system of teeth. This report describes a six-canalled mandibular first molar with four mesial root canals requiring endodontic retreatment. The two additional canals in the mesial root were found during retreatment with the aid of illumination and magnification. In conclusion, the possibility of atypical morphology and additional canals should never be overlooked.

Mandibular first and second molars with three mesial canals: a case series.

Adequate cleaning, shaping and filling of the root canal system are mandatory for successful root canal treatment. Thorough knowledge of root canal morphology and unusual anatomy of the tooth is critical for the practitioner. The occurrence and location of the third mesial canal (Middle Mesial Canal) in mandibular first and second molars in relation to other two mesial canals that were treated in private practice were studied. In 27 clinical cases, the presence of a middle mesial canal was demonstrated. The third canal was located in the middle of the distance between the mesiobuccal and mesiolingual canals. This canal configuration was found in six second lower molars and twenty one first molars. Middle mesial canal in all of our cases joined to mesiobuccal or mesiolingual canals. None of the teeth consisted of three independent canals with three apical foramina. In conclusion, every attempt should be made to find and treat all root canals of a tooth.