The effect of smear layer on bacterial penetration through roots obturated using zinc oxide eugenol-based sealer.

BACKGROUND: Smear layer removal has been shown to reduce bacterial penetration through root canal obturations when resin-based endodontic sealer is used. The purpose of this in vitro study was to test this effect when a non-resin-based sealer is used. MATERIAL AND METHODS: Thirty root segments were assigned to the following groups: Smear layer removed (n = 8); smear layer retained (n = 8); negative controls (n = 10; 5 with smear layer, 5 without); and positive controls (n = 4; 2 with smear layer, 2 without). After rotary instrumentation, smear layers were removed in the treatment group and half of controls using 17% ethylenediamenetetraacetic acid (EDTA) prior to obturation. Each obturated root was affixed into a dual-chamber leakage model employing Streptococcus mutans. Roots were incubated at 37 °C for 120 d. Days until lower chamber turbidity occurred was recorded for each sample, and data were analyzed using Kaplan-Meier survival curve analysis (p = 0.05). RESULTS: No negative controls leaked, while all positive controls were turbid within 1 day. Mean days to leakage for roots with smear layer intact was 82.75 (+/- 33.29, 95% CI), although three never leaked. Mean days to leakage through roots with smear layer removed was 46.25 (+/- 26.67, 95% CI), and all leaked. Treatment survival curves were significantly different (p = 0.048). CONCLUSIONS: Under the conditions and limitations of this study, retaining the smear layer reduced the rate of bacterial penetration through canals which had been obturated using zinc oxide eugenol (ZOE) -based sealer.

Knowledge and practice of, and attitudes toward, pulp therapy in deciduous teeth among pediatric dentists in India.

AIM: The aim of the present study was to assess the knowledge and practice of, and attitudes toward, pulp therapy in deciduous dentition among pediatric dentists. METHODS: A cross-sectional, observational survey was conducted using a closed-ended, multiple-choice questionnaire evaluating the knowledge and practice of, and attitudes toward, pulp therapy in deciduous dentition, which was formulated and sent to 360 pediatric dentists across India. Descriptive statistics were done, followed by χ2 -test to test the association between years of experience and the questionnaire items. RESULTS: A total of 3.5% of pediatric dentists performed their treatment using a rubber dam in all cases; 30% preferred to use local anesthesia prior to indirect pulp therapy (IPT). Traditional indirect pulp capping was preferred to IPT, and only 48% of them believed in not removing it completely. Pulpotomy was preferred over IPT (70%) when there was a probability of pulp exposure following complete caries excavation. Calcium hydroxide, along with iodoform, was the material of choice for the obturation of primary teeth (73.5%). A stainless steel crown was placed after pulp therapy in the primary tooth (86.3%). Most dentists believed requested immediate and 3-month follow up. CONCLUSION: The survey helps in assessing whether our views or approaches are in line with recent trends.

Effect of photodynamic therapy and non-thermal plasma on root canal filling: analysis of adhesion and sealer penetration.

OBJECTIVE: The aim of this study was to evaluate the effect of photodynamic therapy (PDT) and non-thermal plasma (NTP) on adhesion and sealer penetration in root canals. MATERIAL AND METHODS: Sixty single-rooted premolars were used. The teeth were prepared using a crown-down technique. NaOCl and EDTA were used for irrigation and smear layer removal, respectively. The root canals were divided into three groups: control, PDT, and NTP. After treatments, the roots were filled using gutta-percha and either AH Plus (AHP) or MTA Fillapex (MTAF) sealers. Samples were sectioned at 4, 8, and 12 mm from the apex (1-mm slices)and analyzed by the push-out bond strength test (adhesion) and confocal laser scanning microscopy (sealer penetration). Data were statistically evaluated using Kruskal-Wallis, Dunn's, and Spearman's tests. RESULTS: Regarding AHP, bond strength was similar in the NTP group and in the control group, but significantly lower in the PDT group. As to MTAF, both therapies showed lower values than the control group. In the confocal analysis of AHP, maximum and mean penetration, and penetrated area were statistically higher in the control group than in the PDT and NTP groups. Penetrated perimeter was similar among groups. Regarding MTAF, all parameters yielded better results in the NTP than in the control group. The PDT and control groups showed similar results except for penetrated area. CONCLUSION: PDT and plasma therapy affected the adhesion and sealer penetration of root canals filled with AH Plus and MTA Fillapex and there is no positive correlation between adhesion and sealer penetration.

Evaluación de la penetración de cementos obturadores de canales mediante microscopía electrónica de barrido / Evaluation of the penetration of root canal filling cements through scanning electron microscopy

Antecedentes: la literatura odontológica demuestra que los tratamientos endodónticos fallidos, comúnmente son debidos a la persistencia de los microorganismos. Una característica importante de los cementos obturadores de canales es su habilidad para penetrar en los túbulos dentinarios, logrando así un sellado impermeable entre las paredes dentinarias y el material de obturación central, reduciendo las filtraciones potenciales y aumentando la resistencia a la fractura. Objetivo: Evaluar mediante microscopía electrónica de barrido (MEB) la penetración de MTA Fillapex, cemento de Grossman (CG) y top seal a lo largo del conducto radicular. Materiales y métodos: Estudio experimental in vitro, en 36 dientes premolares humanos divididos aleatoriamente en 3 grupos, (n= 12), los cuales fueron preparados con técnica endodóntica Step Back. Cada grupo se dividió en 2 subgrupos utilizando como irrigante NaOCl al 2,5%, al igual que NaOCl al 2,5% + EDTA al 17%. Los canales fueron obturados con técnica de condensación lateral, seccionados longitudinalmente para observar mediante microscopia electrónica de barrido a nivel de los tercios cervical, medio y apical, la penetración del cemento al interior de los túbulos dentinarios. Se realizó análisis estadístico con SPSS v 22 IBM con p< 0,05 y las pruebas Kruskal-Wallis y Mann-Whitney. Resultados: Mediante la prueba Kruskal-Wallis, los cementos de Grossman y top seal al utilizar NaOCl + EDTA presentaron valores de p= 0,025 y p= 0,002 en los tercios medio y apical respectivamente. La prueba de Mann Whitney mostró un valor p= 0,031 en el tercio apical para el cemento MTA Fillapex al utilizar NaOCl. Los valores de la mediana fueron MTA Fillapex tercio medio= 2,0000, tercio apical= 1,0000; top seal tercios medio y apical= 4,0000; cemento de Grossman tercios medio y apical= 4,0000. Al ser igual el valor de la mediana entre los cementos top seal y Grossman se utilizaron los valores de la varianza con un resultado estadísticamente significativo para el cemento de Grossman= 0,276 en el tercio medio y top seal= 0,176 en el tercio apical. La prueba de Mann Whitney arrojó un valor p= 0,031 en el tercio apical para el cemento MTA Fillapex. Con un valor de mediana de NaOCl= 3,0000, NaOCl + EDTA= 1,0000. Conclusiones: Al comparar los cementos obturadores MTA Fillapex, top seal y cemento de Grossman utilizando como irrigante NaOCl + EDTA se observó mayor penetración del cemento de Grossman. A nivel del tercio apical se observó mayor penetración con el cemento top seal. El cemento obturador MTA Fillapex presentó mayor penetración a nivel del tercio apical al utilizar como irrigante NaOC (AU)

Background: the literature has shown that failed endodontic treatments are commonly due to the persistence of microorganisms. One important characteristic of root canal filling cements is their ability to penetrate the dentinal tubules, achieving an impermeable sealing between the dentinal walls and the central filling material, reducing potential filtrations and increasing the resistance to fracture. Objective: To evaluate through scanning electron microscopy (SEM) the penetration of MTA Fillapex, Grossman sealer and top seal all along the root canal. Methods: In vitro experimental study, in 36 human teeth randomly divided into 3 groups, (n= 12), which were prepared with the Step Back endodontic technique. Each group was divided into 2 subgroups using NaOCl 2.5%, and NaOCl 2.5% + EDTA 17% as irrigating solutions. The root canals were sealed using the lateral condensation technique, longitudinally sectioned to observe through scanning electron microscopy the cervical, medium and apical thirds, the penetration of the cement inside the dentinal tubules. The statistical analysis was performed with SPSS v22 IBM with p < 0.05 and the Kruskal-Wallis and Mann-Whitney tests. Results: through the Kruskal- Wallis test the Grossman sealer and top seal when using NaOCl + EDTA showed values of p= 0.025 and p= 0.002 in the medium and apical thirds respectively. The Mann-Whitney test showed a value of p= 0.031 in the apical third for the MTA Fillapex when using NaOCl. The median values were MTA Fillapex medium third= 2.000, apical third= 1.000; top seal medium and apical thirds= 4.000. Since the median values between the top seal and Grossman sealer were the same, the values from the variance were used, with a statistically significant result for the Grossman sealer= 0.276 in the medium third and top seal = 0.176 in the apical third. The Mann-Whitney test showed a value p= 0.031 in the apical third for the MTA Fillapex. With a median value of NaOCl= 3.000, NaOCl + EDTA= 1.000. Conclusions: When comparing the filling cements MTA Fillapex, top seal and Grossman sealer using NaOCl + EDTA as an irrigating solution, more penetration from the Grossman sealer was observed in medium third. At the apical third, more penetration from the top seal sealer was observed. The MTA Fillapex cement showed the greatest penetration at the apical third when using NaOCl as an irrigating solution (AU)

Effect of photodynamic therapy and non-thermal plasma on root canal filling: analysis of adhesion and sealer penetration

Abstract Objective The aim of this study was to evaluate the effect of photodynamic therapy (PDT) and non-thermal plasma (NTP) on adhesion and sealer penetration in root canals. Material and Methods Sixty single-rooted premolars were used. The teeth were prepared using a crown-down technique. NaOCl and EDTA were used for irrigation and smear layer removal, respectively. The root canals were divided into three groups: control, PDT, and NTP. After treatments, the roots were filled using gutta-percha and either AH Plus (AHP) or MTA Fillapex (MTAF) sealers. Samples were sectioned at 4, 8, and 12 mm from the apex (1-mm slices)and analyzed by the push-out bond strength test (adhesion) and confocal laser scanning microscopy (sealer penetration). Data were statistically evaluated using Kruskal-Wallis, Dunn's, and Spearman's tests. Results Regarding AHP, bond strength was similar in the NTP group and in the control group, but significantly lower in the PDT group. As to MTAF, both therapies showed lower values than the control group. In the confocal analysis of AHP, maximum and mean penetration, and penetrated area were statistically higher in the control group than in the PDT and NTP groups. Penetrated perimeter was similar among groups. Regarding MTAF, all parameters yielded better results in the NTP than in the control group. The PDT and control groups showed similar results except for penetrated area. Conclusion PDT and plasma therapy affected the adhesion and sealer penetration of root canals filled with AH Plus and MTA Fillapex and there is no positive correlation between adhesion and sealer penetration.

Assessment of Coronal Leakage of Temporary Restorations in Root Canal-treated Teeth: An in vitro Study.

INTRODUCTION: Coronal leakage is one of the constant concerns in routine dental practice. It is one of the factors responsible for the failure of root canal therapy. Permanent restorations should be given as soon as possible after the completion of root canal therapy. If unavoidable, provisional restoration should be given in such a way that it maximally reduced the leakage of microorganisms and fluids from the external environment into the canal space. Hence, we evaluated the effect of saliva on the coronal leakage of temporary restorations. MATERIALS AND METHODS: Biomechanical preparation of the root canals of 204 fresh mandibular first premolar teeth was done using endodontic files with intermittent irrigation of sodium hypochlorite solution and ethylenediaminetetraacetic acid. Alternate irrigation with normal saline was done periodically. After preparation, drying of the canals was done using paper points followed by sealing of the apical foramen. For the assessment of the microleakage, Siqueira et al apparatus and method was used. All the specimens were divided into four groups based on the provisional restorative material used. All the groups were further divided into three subgroups based on the presence and absence of intracanal medicaments. Verissimo et al's criteria were used to check the turbidity at 1-, 2-, 3-, and 4-week interval respectively. All the results were analyzed by Statistical Package for the Social Sciences (SPSS) software. Chi-square test was used to measure the level of significance, and p < 0.05 was considered to be significant. RESULTS: In group I, all the subgroups' specimens showed significant difference at 1 week's time. Only the subgroup with no intracanal medicaments in Cavit-containing provisional restoration showed nonsignificant alterations. Statistically significant alterations were seen at 1, 2, and 3 weeks' interval in all the subgroups except for one with intracanal medicaments. CONCLUSION: All the temporary restorative materials were not able to prevent microleakage after 1 week's time, with worst bacterial resistance shown by Ketac Molar and ionomer restorative material. Future studies are advocated for better prognosis of root canal therapy.

Effect of different gutta-percha solvents on the microtensile bond strength of various adhesive systems to pulp chamber dentin.

OBJECTIVES: The aim of this study was to evaluate the effect of different endodontic solvents on the microtensile bond strength (µTBS) of various adhesives to pulp chamber dentin. MATERIAL AND METHODS: A total of 120 human third molars were selected. Canals were prepared with the ProTaper Universal system and obturated. The access cavities were then restored with resin composite. After 1 week, a retreatment procedure was applied as follows: control, no solvent was applied to the pulp chamber and experimental groups, three different solvents (chloroform, eucalyptol, and orange oil) were applied to the pulp chamber for 2 min. The canal filling was removed and calcium hydroxide (Ca[OH]2) was placed into the canals. After 7 days, the Ca(OH)2 was removed from the canals and the canals were re-obturated. Teeth were then divided into three subgroups according to the adhesive used. The samples were restored with a nanohybrid resin composite using three different adhesives: Clearfil SE Bond (CSE), Adper Easy One (AEO), and Single Bond 2 (SB2). The samples were aged with thermocycling. Teeth were sectioned, and a total of 20 dentin sticks were obtained for each subgroup. µTBS testing was then performed. The debonded surfaces were evaluated using scanning electron microscopy (SEM) analysis. Data were analyzed using two-way ANOVA and Tukey's post hoc tests. RESULTS: Chloroform showed statistically lower mean µTBS values (14 ± 7.2 MPa) than control group did (19.2 ± 6.1 MPa) (p < 0.05). Orange oil (18.1 ± 6.3 MPa) and eucalyptol (16.9 ± 6.8 MPa) did not reduce the mean µTBS statistically (p > 0.05). Chloroform showed significantly lower bond strength for all adhesives (p < 0.05). Whereas orange oil did not reduce the mean µTBS values of all adhesive systems significantly (p > 0.05), eucalyptol reduced the µTBS values of all the groups, but the results were only statistically significant for SB2 (p < 0.05). CSE showed statistically higher bond strength (20.4 ± 6.8 MPa) than AEO (14.6 ± 5.3 MPa) and SB2 (16.3 ± 7.2 MPa) did (p < 0.05). There were no statistical differences between AEO and SB2 (p > 0.05). According to the SEM analysis of the debonded surfaces, adhesive failures were the most common type in all the groups, followed by mixed failures. CONCLUSIONS: While chloroform reduced the mean bond strength of the adhesive resins, orange oil did not affect the bond strength of the adhesives. The effect of eucalyptol on bond strength depended on the type of adhesive system. CLINICAL RELEVANCE: This study shows that endodontic solvents could affect the microtensile bond strength of adhesives to pulp chamber dentin.

Comparación in vitro de la difusión iónica de pastas de hidróxido de calcio usadas como medicación intraconducto con diferentes vehículos / In vitro comparison of ionic diffusion of calcium hidroxide pastes used as intracanal medication with different vehicles

La medicación intraconducto consiste en la colocación de un medicamento en el interior del conducto radicular. En la actualidad, la pasta de hidróxido de calcio es la más utilizada. Su mecanismo de acción se basa en la disociación de iones oxhidrilos y calcio, responsables de efectos antibacterianos y de reparación tisular. El objetivo de este trabajo fue comparar la difusión de iones calcio y oxhidrilos de la pasta de hidróxido de calcio en el tiempo, utilizando como vehículo agua tridestilada, polietilenglicol y gel de aloe vera. Se utilizaron 45 caninos, se realizó radiografías preoperatorias, aperturas, determinación de la longitud de trabajo para la preparación biomecánica de los conductos. Se rellenaron los especímenes con cada una de las pastas tomando radiografías postoperatorias. Se colocaron las muestras en un medio de análisis almacenándolas en estufa a 37ºC durante 3, 24, 72,168 y 336 horas. Se realizó por triplicado la determinación del pH con pH-metro Metrohm 692 y de la concentración de calcio total utilizando el método espectrofotométrico (reacción del calcio con cresolftaleína complexona a pH 11). Los datos se analizaron estadísticamente por medio de ANOVA aplicando el test de LSD (alfa= 0,05). El comportamiento difusional de las pastas alcalinas con vehículo agua tridestilada y polietilenglicol fue similar en las primeras etapas de experimentación y difirió en las etapas finales. La pasta alcalina con gel de aloe vera mostró un comportamiento de iones oxhidrilos diferente en las primeras etapas de experimentación, el comportamiento de iones calcio fue similar hasta las 168 horas

The intracanal medication consists in placing a medication inside the root canal. At present, the calcium hydroxide paste is most often used. Its mechanism of action is based on the dissociation of calcium ions and hydroxyls responsible for antibacterial effects and tissue repair. The aim of this study was to compare the diffusion of calcium ions and hydroxyls of calcium hydroxide paste in time, using triple distilled water as a vehicle, polietilienglicol and aloe vera gel. 45 canine teeth were used, was performed preoperative radiographs, openings, determining the working length to the biomechanical canal preparation. Specimens with each of the pastes were filled and postoperative radiographs were taken. The samples were placed in a medium of analysis were stored in an oven at 37 ° C for 3, 24, 72,168 and 336 hours. Was performed triplicate pH determination with Metrohm 692 pH meter and the total calcium concentration using the spectrophotometric method (reaction of calcium with cresolphthalein complexone to pH 11). The data were statistically analyzed by ANOVA using the LSD test ( = 0.05). The diffusional behavior of alkaline pasta with water tridistilled -polyethylene vehicle was similar in the initial stages of experiment and in the final stages different. The alkaline paste with aloe vera gel showed a different behavior of hydroxyls ions in the early stages of testing, the behavior of calcium ions was similar up the 168 h

Bacterial penetration along different root canal fillings in the presence or absence of smear layer in primary teeth.

AIMS: To study the effect of the smear layer on the penetration of bacteria along different root canal fillings and to compare the sealing ability of new endodontic material Apexit plus as compared to Zinc Oxide Eugenol (ZOE) in primary teeth. STUDY DESIGN: A total of 60 human root segments were instrumented for endodontic treatment. Half of the sample size was irrigated with normal saline and in other half 3% NaOCl, 3% H2O2 and 17% EDTA was used alternatively as irrigant during instrumentation. The roots were rinsed thoroughly with distilled water and sterilized by autoclaving for 20 min at 121 +/- 2 degrees C. Roots with and without smear layer were obturated with Apexit plus, Zinc oxide eugenol. Following storage in humid conditions at 37 degrees C for 2 days, the specimens were mounted into a bacterial leakage test model for 180 days. RESULTS: At 180 days, there is statistically significant difference with a P value of < 0.05 among all groups except ZOE-smear and -nonsmear. In the presence of smear layer Apexit plus demonstrated more leakage. No leakage was observed in ZOE groups. ZOE demonstrated better sealing ability than Apexit plus. CONCLUSIONS: Removal of smear layer helps in better resistance to bacterial penetration along Apexit plus root canal fillings but no effect is seen along ZOE root canal fillings.

Effect of irrigation with Tetraclean on bacterial leakage of obturated root canals.

The purpose of the study presented here was to evaluate the effect of Tetraclean, Hypoclean, Chlor-XTRA, 2% chlorhexidine and 6% sodium hypochlorite/17% EDTA as a final irrigant on bacterial leakage of the root canal. One hundred and fifty-five extracted human maxillary central incisors were randomly divided into five experimental groups of 25 teeth each and two control groups of 15 teeth each. The root canals in each group were irrigated with 2 ml of the relevant irrigant between each filing. The root canals in group 5 were irrigated with 5 ml of 17% EDTA at the end of root canal preparation. The teeth in each group were obturated with gutta-percha and AH-26 sealer. Positive control teeth were obturated with a single gutta-percha cone without sealer, and negative controls were obturated in the same way as experimental groups. The coronal portion of each root was placed in contact with inoculum of Enterococcus faecalis in Brain Heart Infusion (BHI) culture media. Findings showed that the mean number of days for bacterial penetration in the Tetraclean group was greater than for other experimental groups. On the other hand, the Chlor-XTRA Vista group showed the fewest mean number of days for bacterial leakage.

The effect of sodium hypochlorite and ginger extract on microorganisms and endotoxins in endodontic treatment of infected root canals.

This in vitro study sought to evaluate the biomechanical preparation action on microorganisms and endotoxins by using sodium hypochlorite (NaOCl) and an intracanal medication containing Zingiber officinale, with or without calcium hydroxide. Single-rooted teeth were contaminated, and root canal instrumentation (using 2.5% NaOCl) was performed. Samples were divided into 4 groups, according to the intracanal medication employed. The root canal content was gathered 28 days after contamination (baseline), immediately after biomechanical preparation, 7 days after biomechanical preparation, 14 days after intracanal medication, and 7 days after intracanal medication was removed. The results (submitted to Kruskal-Wallis and Dunn tests) showed that the NaOCl eliminated 100% of root canal microorganisms and reduced 88.8% of endotoxins immediately after biomechanical preparation, and 83.2% at 7 days after biomechanical preparation.

Clinical and radiographic evaluation of zinc oxide with aloe vera as an obturating material in pulpectomy: an in vivo study.

BACKGROUND: Pulp therapy for pulpally involved primary teeth continues to be a challenge to clinicians. One of the major areas of continued research is in the area of finding obturating materials to suit the specific properties of these teeth. Zinc oxide eugenol is used frequently in pulpectomy for the obturation of the primary teeth. AIMS: To evaluate clinically and radiographically a mixture of zinc oxide eugenol and aloe vera as an obturating material. MATERIALS AND METHODS: A total of 50 children, aged between 4 and 9 years, who were screened for unilateral or bilateral carious deciduous molars were studied. Out of these, 15 children were randomly selected for endodontic treatment. Obturation was done with a mixture of zinc oxide powder and aloe vera gel. Clinical and radiographic evaluation was done after 7 days, 1 month, 3 months, 6 months, and 9 months. The data were statistically analyzed. RESULTS AND CONCLUSION: Endodontic treatment using a mixture of zinc oxide powder and aloe vera gel in primary teeth has shown good clinical and radiographic success. A detailed observational study with longer follow-up will highlight the benefits of aloe vera in primary teeth as an obturating medium.

Impact of three radiographic methods in the outcome of nonsurgical endodontic treatment: a five-year follow-up.

INTRODUCTION: The periapical film radiograph (PFR) and digital periapical radiograph (DPR) techniques have some limitations in the visualization of small periapical lesions (PLs) when compared with cone-beam computed tomography (CBCT). However, the evidence supporting their effectiveness is very limited. This retrospective longitudinal cohort study evaluated the outcome of endodontic treatments measured/monitored by PFR, DPR, and CBCT during a 5-year follow-up and also determined the prognostic factors that influenced treatment success. METHODS: A total of 132 teeth (208 roots) with vital pulps received endodontic treatment. The periapical indexes with scores ≥2 for PFR and DPR and ≥1 for CBCT indicated the presence of PLs. Prognostic factors were determined by bivariate and multivariate analyses. Statistical significance was defined at a P level <.05. RESULTS: CBCT detected a higher number of PLs (18.7%, n = 39 roots), followed by DPR (7.7%, n = 16 roots) and PFR (5.7%, n = 12 roots). Likewise, CBCT was more sensitive than PFR and DPR in detecting deficiencies in extension and density of the root canal filling (P ≤ .001). Of the 17 prognostic factors evaluated, 4 were significantly associated with poor outcome to the treatment (P < .05): root canal curvature, disinfection of gutta-percha, presence of missed canals, and the quality of definitive coronal restoration. CONCLUSIONS: The success outcome of endodontic treatment after 5 years in teeth with vital pulps varied with each radiographic method: 94.3%/PFR, 92.3%/DPR, and 81.3%/CBCT.

Use of fluid filtration method to evaluate the effect of master cone size on the apical seal of severely curved root canals.

The apical third of most root canals shows some degree of curvature, which is important in cleaning/shaping and obturation during root canal treatment. The present study evaluated the effect of master cone size on the apical seal of severely curved root canals. Thirty-eight mesial roots of human mandibular first molars were prepared using the crown-down technique. All samples were mature roots with closed apices, had no carious lesions or resorption, and had a canal curvature of > 45º to 60º. Two samples were used as a negative and positive control to evaluate the fluid filtration equipment, and the remaining 36 samples were equally divided into groups A, B, and C based on master cone size, namely, gutta-percha #20, #25, and #30, respectively. The fluid filtration method was used to evaluate microleakage. No significant difference in microleakage was observed among groups (P = 0.31). In conclusion, an increase in master cone size up to #30 does not significantly influence apical microleakage.

Evaluation of microleakage of root canal fillings irradiated with different output powers of erbium, chromium:yttrium-scandium-gallium-garnet laser.

This study evaluated the root canal seal achieved by irradiation with an erbium, chromium:yttrium-scandium-gallium-garnet laser, and the optimal output power to remove debris and the smear layer were determined. One hundred mandibular premolar teeth were prepared and divided into four groups. Group 1 was not lased but was irrigated with 5 mL of 5.25% NaOCl and 5 mL of 17% ethylenediaminetetraacetic acid. Group 2 was irradiated at a panel setting of 1 W, group 3 at 2 W and group 4 at 2.5 W, with a 50% water level and 48% air-cooling level. Root canals were obturated by cold lateral compaction, and apical microleakage was measured using a fluid filtration model. The remaining debris and smear layer were evaluated via scanning electron microscopy. Statistically significant differences were detected between groups. Irradiation at 1 and 2 W using an erbium, chromium:yttrium-scandium-gallium-garnet laser produced a seal superior to that of the other treatments.

Self-adjusting file cleaning-shaping-irrigation system improves root-filling bond strength.

INTRODUCTION: The aim of the present study was to assess the bond strength of root fillings in oval-shaped canals prepared with the self-adjusting file (SAF) system. METHODS: A careful specimen selection resulted in 2 equal groups, each consisting of 12 extracted mandibular canines with oval canals that had vital pulps before extraction. One group was subjected to the SAF protocol, and the other group underwent conventional protocol, which was the ProTaper system with syringe-needle irrigation. Full-strength sodium hypochlorite was used as an irrigant for both groups. The teeth were obturated in a standardized way, filled with a lentulo spiral as the root filling, and then prepared for micropush-out assessment by using root slices of 1-mm thickness. Loading was performed on a universal testing machine at a speed of 0.5 mm/min(-1). The Student's t test for pairwise comparisons was applied to assess the effect of each preparation technique on the push-out bond strength. RESULTS: All specimens showed measurable adhesive properties to root dentin. In addition, no premature failure occurred. The group-by-location interaction was significant (P = .0071); thus, the group comparisons were dependent on the canal third. Overall, the push-out bond strength was the highest in the coronal third and the lowest in the apical third. SAF-prepared specimens displayed significantly higher bond strengths (P = .0012, 0.51-5.9 MPa). CONCLUSIONS: The present study showed that SAF preparation markedly influenced root-filling push-out bond strength in oval-shaped canals. Further investigations are needed to provide a better understanding of the physicochemical modifications of the root dentin prepared with the SAF cleaning-shaping-irrigation system.

Comparison between two thermoplastic root canal obturation techniques regarding extrusion of root canal filling--a retrospective in vivo study.

OBJECTIVES: The aim of this study was to compare two different thermoplastic techniques--a core-carrier technique (Thermafil) and warm vertical compaction--in terms of overextension of root canal filling in vivo. MATERIALS AND METHODS: Flaring of 88 teeth was conducted using Pro Files .04 as finishing files, and the teeth were obturated using Thermafil. Flaring of 74 teeth was performed using Pro Files .06 as finishing files, and the teeth were obturated using warm vertical compaction. RESULTS: Seventy (80 %) of the teeth obturated using Thermafil and 31 (42 %) teeth obturated using warm vertical compaction show extruded root canal filling. In contrast to Thermafil, there is a higher rate of extruded root canal filling of teeth with more than one root canal using warm vertical compaction. CONCLUSION: Thermafil demonstrated a higher rate of extruded root canal filling compared to warm vertical compaction. Warm vertical compaction is a more predictable method of filling compared to Thermafil. CLINICAL RELEVANCE: Root canal filling extrusion will cause irritation of the surrounding tissue and impair repair processes. In the present in vivo study, there was a higher rate of root canal filling extrusion using Thermafil compared to warm vertical compaction.

Efficacy of articaine versus lidocaine in block and infiltration anesthesia administered in teeth with irreversible pulpitis: a prospective, randomized, double-blind study.

INTRODUCTION: Profound pulpal anesthesia in posterior mandibular teeth with irreversible pulpitis usually requires administering an inferior alveolar nerve block (IANB) plus other supplemental injections. The purpose of this prospective, randomized, double-blind study was to compare the anesthetic success rate of buccal infiltration injections of articaine and lidocaine when supplemented with an IANB. METHODS: One hundred twenty-five emergency patients who had their first or second mandibular molar diagnosed with irreversible pulpitis participated in the study and received the IANB by using either 2% lidocaine with 1:100,000 epinephrine or 4% articaine with 1:100,000 epinephrine. One hundred two of the patients reported moderate-to-severe pain upon initiation of their endodontic treatment or through filing of their tooth canals and received supplemental buccal infiltration injections by using the same anesthetic that the IANB had been performed. After the block or the supplemental buccal infiltration injections, success was achieved with no or mild pain during instrumentation of the tooth canals. RESULTS: The success rate after the administration of the infiltration injections after an incomplete IANB by using lidocaine was 29%, whereas by using articaine it was 71% (P < .001). No statistical differences were detected in the success rates between the 2 anesthetics after the block injections. CONCLUSIONS: Supplementing an incomplete articaine IANB with articaine infiltration raises the anesthetic success more effectively compared with lidocaine in mandibular molars with irreversible pulpitis.

Portland cement with additives in the repair of furcation perforations in dogs.

PURPOSE: To evaluate the use of Portland cements with additives as furcation perforation repair materials and assess their biocompatibility. METHODS: The four maxillary and mandibular premolars of ten male mongrel dogs (1-1.5 years old, weighing 10-15 kg) received endodontic treatment (n=80 teeth). The furcations were perforated with a round diamond bur (1016 HL). The perforations involved the dentin, cementum, periodontal ligament, and alveolar bone. A calcium sulfate barrier was placed into the perforated bone to prevent extrusion of obturation material into the periradicular space. The obturation materials MTA (control), white, Type II, and Type V Portland cements were randomly allocated to the teeth. Treated teeth were restored with composite resin. After 120 days, the animals were sacrificed and samples containing the teeth were collected and prepared for histological analysis. RESULTS: There were no significant differences in the amount of newly formed bone between teeth treated with the different obturation materials (p=0.879). CONCLUSION: Biomineralization occurred for all obturation materials tested, suggesting that these materials have similar biocompatibility.