Evaluation of Students' Proficiency in Removing Gutta-Percha Prior to Fiber Post Placement: A Retrospective Study

INTRODUCTION

This retrospective study focuses on dental students' proficiency in removing gutta-percha during fiber post space preparation, which is important for maintaining apical seal integrity in endodontically treated teeth. Emphasizing the significance of preventing further reinfection. The primary objective of this study was to assess the proficiency of undergraduate dental students in the manipulation of gutta-percha during fiber post preparation, specifically focusing on the psychomotor skills involved. In addition, the study aims to determine the predictive value of these skills on the ultimate clinical outcomes of the procedure, with particular emphasis on variations attributable to tooth type.

MATERIALS AND METHODS

The analysis encompassed 290 periapical radiographs obtained from endodontically treated teeth, all of which had undergone fiber post placement by undergraduate students at the College of Dentistry, Taibah University, Saudi Arabia. Postoperatively, the length of the remaining gutta-percha was measured by two experts in the field, and subsequent outcomes were classified into three categories: optimal, suboptimal, and inadequate, based on the extent of gutta-percha remaining.

RESULTS

Students showed optimal removal rates ranging from 33.3% to 73.1%. Among the studied sample, upper anterior teeth were the highest included teeth (n=117, 40%). Remarkably, lower anterior teeth were more prone to suboptimal and inadequate gutta-percha remaining lengths (n=24, 33%). However, the chi-square test revealed no statistically significant difference in students' psychomotor skills while removing the gutta-percha and preparing the teeth to receive fiber posts across tooth types (p-value > 0.05).

CONCLUSION

With the limitations of this study, more than half of the included cases show that undergraduate students of the College of Dentistry at Taibah University, Saudi Arabia, possess an optimum level of psychomotor skills in removing gutta-percha while preparing the teeth for receiving fiber posts. This study suggests enhancing the preclinical training of students by considering more training on different tooth types in relation to dental arches.

A Comparative Evaluation of Push-Out Bond Strength of Six Different Root Canal Sealers: An In-Vitro Study

BACKGROUND

Adhesiveness with radicular dentin is absent with gutta-percha, leading to microleakage and hence re-infection. Root canal sealer helps to achieve an adhesive interface between gutta-percha and root dentin thereby resisting the displacement forces during the functioning of teeth which is evaluated by the push-out test. The aim of this study is to compare the push-out bond strength and to assess the relative bond failure between dentin-sealer, sealer-main cone of (1) epoxy resin, (2) silicon, (3) mineral trioxide aggregate (MTA), (4) calcium hydroxide, (5) bioceramic, (6) zinc oxide eugenol containing root canal sealers.

METHODOLOGY

Sixty human permanent lower premolars with one root were collected, disinfected, and decoronated at cemento-enamel junction. Instrumentation was done with a K3 40,0.06 Ni-Ti rotary file and obturated using the main cone and sealer. Based on the sealer utilized, six groups were created: Group 1: AH-Plus, Group 2: RoekoSeal, Group 3: MTA Fillapex, Group 4: Apexit, Group 5: Smart Paste Bio, and Group 6: Procosol. One slice each was obtained from the coronal, middle, and apicalsections of all the obturated canals. Push-out bond strength and failure modes were studied. Statistics involved analysis of variance (ANOVA) followed by the post hoc Tukey test.

RESULTS

All three sections exhibited the highest strength for Smart Paste Bio sealer and the least was for RoekoSeal. With all the sealers, the apical section had the highest strength followed by the middle and coronal.

CONCLUSION

The smart seal system was superior to all other sealers and displayed a good bond to dentin.

Tensile Strength and Elastic Modulus of Gutta-percha Cones Disinfected with Sodium Hypochlorite at Different Immersion Times: An In Vitro Comparative Study

Aim

The tensile strength and modulus of elasticity of gutta-percha cones can be chemically altered due to disinfectant solutions. Therefore, the aim of the present study was to compare tensile strength and elastic modulus of gutta-percha cones subjected to sodium hypochlorite (NaOCl) disinfection at different times.

Materials and Methods

This in vitro and longitudinal experimental study consisted of 45 gutta-percha cones, divided equally into three groups: Group 1 (disinfection with 2.5% NaOCl), Group 2 (disinfection with 5.25% NaOCl), and control group. All groups were subdivided according to immersion times for 1, 5, and 10 minutes. Tensile strength and elastic modulus were measured with a universal testing machine. For comparing more than two independent groups, parametric analysis of variance test with Sheffe's post hoc was used and for multivariate analysis, and multivariate analysis of variance test based on Pillai's Trace was used. In all statistical analysis, a significance level P ≤ 0.05 was considered.

Results

When comparing the tensile strength of gutta-percha cones, no significant differences were observed after being immersed at 1, 5, and 10 minutes in NaOCl 2.5% (P = 0.715) and 5.25% (P = 0.585). Regarding the elastic modulus, a significant decrease (P < 0.05) was observed in those that were immersed in NaOCl 2.5% and 5.25% for 1, 5, and 10 minutes. Furthermore, increased NaOCl concentration significantly reduced the elastic modulus (P < 0.001). However, there were no significant differences in tensile strength (P > 0.05) and elastic modulus (P > 0.05), when evaluating the interaction between NaOCl concentration and time.

Conclusion

Increasing NaOCl concentration significantly reduced the modulus of elasticity without affecting the tensile strength of gutta-percha cones, regardless of immersion time. Furthermore, the interaction of time and NaOCl concentration did not significantly affect the tensile strength and elastic modulus.

Effectiveness of root canal filling materials and techniques for treatment of apical periodontitis: A systematic review

BACKGROUND

Apical periodontitis (AP) is an inflammatory disease of the apical periodontium as sequelae of pulp death. It is managed by disinfection and filling of the root canal space.

OBJECTIVES

The aim of this systematic review was to investigate whether obturation techniques and materials used for root canal filling led to the management of AP.

METHODS

A systematic review protocol was written following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist and registered on the international prospective register of systematic reviews (PROSPERO; CRD42021260275) including two populations, interventions, comparisons, outcomes and time (PICOT) for the research questions querying the effectiveness of obturation techniques (PICOT 1) and materials (PICOT 2) for the management of AP. Electronic searches were conducted on PubMed, ScienceDirect, Scopus and Embase search engines. Searches on International Endodontic Journal, Journal of Endodontics, Clinical Oral Investigations, Journal of Dental Research and Journal of Dentistry websites were also conducted, until May 2021. Both primary (tooth survival) and secondary outcomes were evaluated. The risk of bias was assessed by Cochrane RoB2 for the randomized and ROBINS-I for the nonrandomized trials.

RESULTS

The search strategy identified 1652 studies, with 1600 excluded on the title and abstract screening, leaving 52 studies for full-text screening. In total, 10 studies met the inclusion criteria. The obturation technique and materials used did not affect the outcome of AP. Vertical compaction resulted in faster resolution of periapical lesions. The oral health-related quality of life of patients treated with lateral condensation exhibited poorer outcomes compared with single matched cone after 6 months of recall.

DISCUSSION

The inclusion and exclusion criteria used for this systematic review enabled the capture of all the literature available on the effect of obturation techniques and materials on the outcome of AP. The data were heterogenous, and a number of articles investigating obturation techniques had no information on the materials and techniques used as they looked at the quality of fill.

CONCLUSIONS

Included studies did not find any difference between different procedures (PICOT 1) and materials (PICOT 2). The risk of bias was high, thus the findings should be interpreted with caution.

REGISTRATION

PROSPERO registration number: CRD42021260275.

Comparison of the apical seal obtained by Adseal, Proseal, and AH26 sealers in root canal obturation with lateral compaction technique

Background

Root canal obturation is an important step in endodontic treatment, which is performed aiming to three-dimensionally seal the canal and prevent microleakage, reentry, and proliferation of microorganisms in the root canal system. On the other hand, microleakage eventually leads to root canal treatment failure. Sealing ability is an important property of endodontic sealers. This in vitro study aimed to compare the quality of apical seals obtained by three endodontic sealers.

Materials and Methods

This in vitro experimental study evaluated 48 extracted single-canal maxillary incisors. Hard- and soft-tissue residues were removed and the teeth were immersed in 5.25% of sodium hypochlorite for disinfection. The teeth were decoronated at the cementoenamel junction with a diamond disc such that 10 mm of root length remained. Canal patency was ensured using a #10 K-file. The canals were then instrumented with ProTaper rotary system. The canals were randomly divided into three experimental groups for the application of Adseal, Proseal, and AH26 sealers, and positive and negative control groups. Sealers were applied in the canals using lateral compaction technique. The external root surfaces were then coated with two layers of nail varnish except for the apical 3 mm. The amount of microleakage was quantified using the dye-penetration technique. The Tukey's test was used to compare the microleakage between the experimental and control groups. The Kruskal-Wallis test was applied to compare the microleakage of experimental groups (P < 0.05).

Results

The amount of microleakage in canals filled with Adseal, Proseal, and AH26 sealers with lateral compaction technique was 2.33 ± 0.64, 2.2 ± 0.81, and 2.22 ± 0.71 μm, respectively. No significant difference was noted among the three sealers regarding microleakage (P = 0.84). However, the amount of microleakage in the sealer groups was significantly lower than that in the control group (P < 0.001).

Conclusion

The application of Adseal, Proseal, and AH26 had equal efficacy for the provision of optimal apical seal in filling of root canals with lateral compaction technique. The application of sealers yielded a significantly superior apical seal compared with the control group.

Efficiency of diode laser and ultrasonic-activated irrigation in retreatment of gutta percha and bioceramic sealer: An in vitro study

This study was to determine the effectiveness of diode laser (LI) and ultrasonic (UI)-activated irrigation with or without a surfactant as adjunct techniques during the retreatment of gutta-percha and tricalcium silicate-based sealer (BC) sealer. Forty-two single-rooted premolars were instrumented and filled with gutta-percha and BC sealer, then retreated using NiTi retreatment rotary files. Teeth were randomly divided into three equal groups: Control (manual irrigation), UI and LI groups. Each group was subdivided into 2.5% NaOCl irrigant and ChlorCid™️ Surf subgroups. The amount of material removed following UI and LI was significantly greater than that of manual irrigation (p < 0.0001). However, there was no significant difference between the surfactant subgroups, irrespective of irrigation technique (p = 1.00, p = 0.535, p = 0.805). The use of UI and LI adjuncts to NiTi rotary retreatment techniques showed significant improvement in gutta-percha with BC sealer removal. However, surfactants had no effect on the efficacy.

Quantitative Assessment of Dimensional Evaluation and Artefacts from Filling Materials with CBCT Using Standard Phantom Roots

OBJECTIVE

To investigate the accuracy of dimensional evaluation and representation of artefacts generated by different gutta-percha (GP) cones with or without sealer with CBCT using a reproducible, standardised phantom root methodology.

METHODS

The reproducible artificial phantom roots with six root canal sizes from #25 to #50 and 0.04 taper were aligned according to the jaw curvature in a stone model for dimensional measurements. Each root was scanned while empty and filled with four types of filling materials. The specimens were scanned using the CS 9300 3D (Carestream Dental, Rochester, NY, USA) (at two different resolutions), 3D Accuitomo (J Morita, Kyoto, Japan) and NewTom VGi (Verona, Italy) CBCT systems. The hyperdense and hypodense axial slice artefacts from root canal sizes #40, #45 and #50 were recorded.

RESULTS

Dimensions were significantly smaller and more accurate with CS 9300/0.09 mm voxel size than with other protocols. The hypodense band was found mostly in the CS 9300 3D system with 0.18 mm voxel size, especially in the buccal-lingual (95%) and coronal (64%) sections. The 3D Accuitomo CBCT system showed the lowest presence of the hypodense band. Areas of both light and dark artefacts were significantly larger in the coronal third than in the apical and middle thirds.

CONCLUSION

Artefacts in the coronal locations and in buccal-lingual sections were more evident in the CS 9300 3D system with a 0.18-mm voxel size.

Determination of Antifungal Effect of Natural Oil and Synthetic Gutta Percha Solvents Against Candida Albicans: A Disc Diffusion Assay

Introduction

The practice of removing root canal fillings with solvent materials is frequently required to help an irrigation solution enter the tubules. The current research was aimed at assessing the antifungal properties specifically the candida albicans of the various solvent materials used for the gutta-percha (GP) material.

Materials and Methods

Current research was aimed at as a lab method using the disk diffusion technique where the zone of inhibition (ZOI) was calculated. The materials that were analyzed were: orange oil, xylene, turpentine oil, chloroform, and eucalyptus oil. Candida albicans was the test organism employed in the investigation. The agar plates were covered with approximately 500 μL of the suspension. The sterile and empty disks were impregnated with 10 μL of pure GP solvents. These plates were incubated for one day at room temperature. The ZOI's mean diameters were calculated for all five materials and quantified each solvent's fungicidal activity. For intergroup comparison, ANOVA was utilized. P values < 0.05 were deemed substantial.

Results

The maximum inhibition exhibited by the Eucalyptus Oil it was 19.01 ± 1.02 mm. This was followed by Xylene. The other three solvents Chloroform, Orange Oil, and Turpentine Oil exhibited a similar ZOI. When all the solvents were compared there was a significant variance of P < 0.001. However, there were significant variances for the Eucalyptus Oil and the Xylene to all the other solvents P < 0.001.

Conclusion

This investigation showed that, in comparison to other solvents, the use of eucalyptus oil considerably reduced the levels of Candida Albicans.

Endodontic Microsurgery on a Persistent Periapical Lesion

Extrusion of root filling material had been shown to reduce the success of endodontic treatment. This case report describes the management of a patient who reported prolonged, persistent, and increasing pain on an upper root filled central incisor with extruded root filling material. A 28-year-old female patient came with the chief complaint of pain and tenderness on the upper left central incisor. The pain was mostly triggered by mastication. Upon examination and investigation, the tooth of concern was tooth 21 which was a root treated many years ago. It appeared to have tenderness on percussion and palpation. Non-surgical root canal retreatment was completed on tooth 21. However, the patient complained of the same pain while biting even after six months post-obturation. Therefore, endodontic microsurgery was performed to remove the root filling material that was extruded and to enucleate the granulomatous lesion around the periapical region of tooth 21. After enucleation, apical root end resection was performed. Postoperatively, the patient reported comfort and no pain and was able to resume her daily activities. At six months of review, the radiograph showed evidence of complete healing. This case report captured the importance of endodontic microsurgery as a viable treatment option where nonsurgical root canal retreatment failed to relieve the patient's symptoms.

Clinical usability of vasundhara's transit for gutta-percha (V transit GP) - A questionnaire-based survey

Context

The lack of a suitable armamentarium to aid in the disinfection and handling of gutta-percha (GP) cones during obturation has been a common challenge amongst dentists.

Aims

This study assessed the clinical usability of 'Vasundhara's (V) Transit GP' through a questionnaire-based survey.

Settings and Design

This questionnaire-based study was conducted in Davanagere, Karnataka, in February 2021 for 4 months.

Methods and Material

The design was 3D printed using a heat-resistant polypropylene material and named 'Vasundhara's Transit for Gutta Percha (V Transit GP)'. Eighteen postgraduate students participated in the study. Fourteen cases were done by each student, seven without and seven with the use of 'V Transit GP'. The GP cones, before obturation, were transferred to their respective canal slots containing 5.25% sodium hypochlorite for one minute and then transferred to their respective distilled water slots. The cones were dried with sterile gauze and taken for obturation. At the end of the procedure, a questionnaire was handed out, the responses were recorded, and the results were tabulated and analysed using Statistical Package for the Social Sciences (SPSS) version 22.0 software.

Results

The results showed that without the use of 'V Transit GP', 84.2% of the dentists felt that the disinfection and handling of GP cones were difficult, whereas with the use of 'V Transit GP', 94.2% of the participants found it to be extremely easy.

Conclusions

'V Transit GP' proved to be an extremely efficient and user-friendly equipment for easy handling and disinfection of GP cones during obturation.

Evaluation of antimicrobial efficacy of nanocurcumin-coated gutta-percha against Enterococcus faecalis: An in vitro study

Background

Nanocurcumin has antimicrobial properties and it is to be tested as a coating on gutta-percha against Enterococcusi faecalis.

Aim

To evaluate the antimicrobial efficacy of nanocurcumin-coated gutta-percha against E. faecalis in comparison with conventional gutta-percha.

Materials and Methods

The broth dilution method and colony-forming unit count assay were chosen for the evaluation of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration of nanocurcumin against E. faecalis. ISO size 30, 4% taper gutta-percha cones were manually coated with nanocurcumin. All the coated and noncoated gutta-percha cones were examined under a scanning electron microscope to study the exterior surface. Antibacterial efficacy of nanocurcumin-coated gutta-percha and conventional gutta-percha was seen by agar diffusion method against E. faecalis.

Results

MIC of nanocurcumin was observed at 50 mg/ml for E. faecalis. Nanocurcumin-coated gutta-percha showed a larger zone of inhibition when compared to conventional gutta-percha which showed a smaller zone of inhibition (P < 0.0001). Nanocurcumin-coated gutta-percha showed moderate antimicrobial activity, while conventional gutta-percha showed weak activity.

Conclusion

The results of the study reveal that nanocurcumin has an antimicrobial activity against E. faecalis. The use of herbal alternatives in endodontics might prove to be advantageous.

Influence of Gutta-Percha Surface on Enterococcus faecalis Initial Adhesion In Vitro: An Atomic Force Microscopy Study

The aim of this study was to evaluate the influence of surface topography of gutta-percha (GP) cones and plasticized disks of GP on the initial adhesion of Enterococcus faecalis (E. faecalis). The GP cones (Tanari and Dentsply brands) were cut 3 mm from the apical portion and fixed on a glass slide. To make the disks, the cones were thermoplasticized in standardized molds. The specimens were divided into groups according to the shape of the GP and the presence or absence of the bacteria. For contamination, the strain of E. faecalis (ATCC 29212) was used. The surface topography was analyzed using an atomic force microscope (AFM). The surface, roughness, and waviness parameters were evaluated by the Kruskal-Wallis and Dunn test. The comparison between disks and cones showed significant differences, where the cones were rougher, with a higher value attributed to the Dentsply cone (DC group). The same was observed for the waviness. After contamination, there was greater bacterial accumulation in cones, especially in their valleys, but both the surface and the topography became more homogeneous and smoother, with no differences between disks and cones of both brands. The topographic surface of the GP, at the micro and nanoscale, influences the initial adhesion of E. faecalis, with a greater tendency for contamination in regions associated with the presence of roughness and waviness. In this context, plasticization of GP is indicated, as it reduces surface irregularities compared to cones, contributing to less retention of bacteria.

Thermal and volumetric assessment of endodontic filling techniques using infrared thermography and micro-CT

PURPOSE

To assess root temperature during filling techniques and quantify the volume of endodontic filling materials using infrared thermography (IT) and micro-computed tomography (micro-CT).

METHODS

Ninety premolars were divided into three groups: lateral condensation (LC), single cone (SC) and thermomechanical compaction (TMC). For thermal analysis, 45 teeth were assessed using a FLIR T650sc IT camera during filling techniques and 45 teeth were scanned using a Nikon micro-CT to assess gutta-percha, cement, and void volumes. Descriptive and inferential statistical analyses were performed (non-parametric Mann-Whitney test, Kruskal-Wallis test, and Friedman test with Tukey's bidirectional analysis of variance).

RESULTS

TMC showed the highest temperature increase at 15 s after the procedure and a significant temperature decrease at 45 s after its completion. TMC showed the largest volume of gutta-percha and LC the highest void volume.

CONCLUSION

The temperature increase generated by gutta-percha endodontic filling techniques is within acceptable limits. A greater volume of endodontic cement was observed for the SL and LC filling techniques.

Filling Materials Efficacy on Preventing Biofilm Formation Inside Screw Access Channels of Implant Abutments

The choice of the material used to fill screw access channels in implant-supported prostheses depends, in most cases, on operator's preference, without considering the susceptibility of biofilm colonization. Therefore, the aim of this study was to determine and compare the total amount of biofilm formed on different materials used to fill screw access channels in implant abutments. For this propose, titanium implant analogs were attached on abutments and divided into 5 groups: positive control (no filling material); negative control (closed with resin); and filled with cotton, gutta-percha, or polytetrafluoroethylene (PTFE). The analogs with attached abutments were then immersed in a brain heart infusion medium containing Candida albicans (strain 10231 from American Type Culture Collection [ATCC]) and incubated aerobically at 37°C with gentle agitation. After 15 days, materials were removed, and total viable biofilm on each material was quantified by methyl tetrazolium reduction assay at 490 nm. All experiments were performed in triplicate. Data were processed by IBM SPSS Statistic software using 1-way analysis of variance and Bonferroni post hoc tests to analyze differences between groups, with an overall significance level of P < .001. A significant difference was observed between cotton and gutta-percha (P < .017) and between cotton and PTFE (P < .025). However, there was no statistical difference between gutta-percha and PTFE (P > .050). Thus, this in vitro experiment showed that gutta-percha and PTFE presented lower biofilm formation compared with cotton when used to fill screw access channels. These results can provide a basis for future clinical studies that can be a guide to decreasing the occurrence of gaps and bacterial growth inside the implant/abutment attachment site. In addition, controlled in vivo studies are necessary to confirm the clinical viability of findings of this study.

Micro-CT assessment of gap-containing areas along the gutta-percha-sealer interface in oval-shaped canals

AIM

To assess the interfacial adaptation (gap-containing areas) of two root canal sealers (EndoSequence BC Sealer and AH Plus) to a conventional gutta-percha (GP) cone (GP-sealer interface) in oval-shaped canals filled using the single cone technique.

METHODOLOGY

Sixteen teeth with oval-shaped canals were selected, scanned in a micro-computed tomographic device, and pair-matched according to the volume, aspect ratio and configuration of root canals. Root canals were then sequentially prepared with WaveOne Gold Primary and Large instruments, followed by filling with WaveOne Large GP points associated with either the premixed calcium-silicate EndoSequence BC Sealer or the epoxy resin-based AH Plus sealer (n = 8 per group) using the single cone technique. After 7 days stored in phosphate-buffered saline solution at 37°C, the specimens were rescanned and the reconstructed images segmented in order to differentiate the filling materials (sealer and GP cone) to the dentine. A total of 453 cross-sectional slices were assessed and categorized according to the presence or absence of gaps at the GP-sealer interface. Mann-Whitney U-test verified the differences between groups and were considered significant at alpha = 5%.

RESULTS

Gaps were non-homogenously distributed in two-dimensional axial cross-section images and none of the specimens showed completely gap-free areas along the entire GP-sealer interface. Root canals filled with EndoSequence BC Sealer and AH Plus displayed 171 (37.75%) and 136 (30.02%) slices with gaps in the GP-sealer interface and these frequencies were statistically significant (p = .000).

CONCLUSIONS

Although none of the specimens had a gap-free area along the entire GP-sealer interface, oval canals filled with AH Plus showed less gaps than the ones filled with EndoSequence BC Sealer.

Ability of two reciprocating Nickel-Titanium instruments for guttapercha/ sealer removal in simulated curved root canals

The aim of this study was to compare the capacity of two reciprocating NiTi instruments in removing gutta-percha/sealer material from simulated curved root canals (SCRC). The time required for filling material removal was also recorded. Twenty SCRCs were divided into two groups of 10 (n=10) samples each. In Group 1, the SCRC were prepared to a R25 Reciproc Blue instrument (RCPB; VDW, Munich, Germany). In Group 2 the SCRC were prepared to a Primary WaveOne Gold instrument (PWOG; Dentsply, Ballaigues, Switzerland). In both groups, the canals were filled with matched-taper single gutta-percha cones and AH Plus sealer. Filling materials were removed with R25 RCPB (Group 1) and PWOG (Group 2). The amount of remaining gutta-percha/sealer was calculated at three predetermined levels of evaluation located at 2, 6 and 10 mm from the WL and expressed in percentages. Canals re-treated with RCPB contained significantly less remaining gutta-percha/sealer compared tocanalspreparedwith PWOG (P=0.02). The RCPB instruments required significantly less time to complete the retreatment procedures (P<0.01). No unwinding or instrument separation was noted. RCPB instruments removed significantly more gutta-percha/sealer from simulated curved root canals than PWOG. However, neither of the tested instruments completely removed all filling materials.

[In vitro study of the effect of three commercial solvents on gutta-percha cones used for the cold and thermoplastic technique]

The objective of this research was to compare the solvent action of orange oil, eucalyptol and experimental lemongrass oil on gutta-percha cones for cold technique and thermoplastic technique.

Methodology

The sample consisted of 80 gutta-percha cones No. 80 Endomedic and F3 ProTaper Universal. The cones were divided into 4 groups (n = 20) according to the type of solvent, and each one was divided into two subgroups (n = 10) according to the exposure time (5 min and 10 min). The cones were immersed in the respective solvent for 5 or 10 minutes. Then, they were washed with 5 ml of alcohol for 5 minutes and rinsed with water. Finally, after drying at room temperature for one hour, the solvent action was recorded in grams (g) of weight loss. The results were analyzed and compared using Tukey's test (p<0.05).

Results

The Endomedic cone exposed for 5 min to eucalyptol obtained the lowest average weight (0.0625 ± 0.0009 g), followed by Lemongrass oil (0.0629 ± 0.0003 g) and orange oil (0.0629 ± 0.0010 g), although not a significant difference (p > 0.05) was found between each one.

Conclusion

The experimental solvent of Lemongrass, eucalyptol and orange oil presented a similar solvent effect on the guta-percha cone for cold and thermoplastic technique. At a clinical level, the three solvents studied could be used in endodontic retreatment as alternative solutions with a similar solvent effect.

Effect of a heat-based root canal obturation technique on push-out bond strength of the classical bioceramic and new HiFlow sealer

This study aimed to investigate the effect of the heat-based obturation technique on the push-out bond strength of the classical bioceramic and new HiFlow sealer. Fifty single-rooted human mandibular premolars were obturated using one of the following techniques: (1) BC-SC; (2) BC-W; (3) HiFlow-SC; (4) HiFlow-W; and (5) AH Plus-W. Following obturation, specimens were sectioned into 1-mm-thick root slices 4 and 8 mm from the working length and were subjected to a push-out bond test using a universal testing machine and examined for their modes of failure under an inverted phase-contrast microscope. At both distances tested, there was no difference in the push-out bond strength among the four bioceramic groups (P > 0.05). The AH Plus-W group had lower bond strength than every other group at both distances from the working length. The most common failure mode was mixed failure.

Antimicrobial efficacy of acacia Nilotica (Babul) extract and its effectiveness in disinfecting gutta percha cones - An in vitro study

Background

Gutta-percha cones used directly from the manufacturer's sealed packs harbour micro-organisms. During clinical use, the chances of contamination of gutta-percha increases. Hence, disinfection of gutta-percha cones before use is essential to prevent canal recontamination.

Aim

To evaluate the antimicrobial efficacy of babul against chemical disinfectants, and its effectiveness in disinfecting gutta-percha cones.

Materials and Methods

The extract of babul was used to assess its antimicrobial activity against E-faecalis, S. aureus and C. albicans using the agar diffusion method. A total of 120 cones acquired from freshly opened manufacturers' pack were cut into three equal parts and divided into group I which was directly placed into a nutrient broth, group II was clinically contaminated with gloves for 30 s and placed into a nutrient broth, and the third part was clinically contaminated with gloves and decontaminated for 5 min using the experimental disinfectants to check for the presence of turbidity.

Statistical Analysis

The data were analysed by an Unpaired t-test and Chi-square test at a significance level of P < 0.05 using software SPSS 20.

Results

Two percent chlorhexidine showed maximum antibacterial action against E. faecalis and S. aureus followed by babul extract. It was also found more efficacious in decontaminating gutta-percha cones followed by babul and 3% sodium hypochlorite in 5 min.

Conclusion

Babul herbal extract is indeed effective in decontaminating gutta-percha cones and is a better alternative to chemical disinfectants.

Ultrasonic Microwave-Assisted Micelle Combined with Fungal Pretreatment of Eucommia ulmoides Leaves Significantly Improved the Extraction Efficiency of Total Flavonoids and Gutta-Percha

A biological pretreatment of Eucommia ulmoides leaf biomass was carried out. Above all, the total flavonoids were isolated from Eucommia ulmoides leaves by the treatment of alkaline solution of sodium dodecyl benzene sulfonate combined with ultrasonic microwave. The extraction parameters were optimized by central composite design (CCD) software and were displayed as follows: surfactant concentration of 1.5%, microwave power of 700 W, extraction time of 30 min, and liquid-solid ratio of 50 mL/g. The actual yield of total flavonoids was 1.45%. The results of Sudan III color development showed that the cuticle of Eucommia ulmoides leaves was completely removed after dilute alkali pretreatment. Then, Eucommia ulmoides leaves were fermented by Trichoderma viride to remove the holocellulose and obtain gutta-percha. The content of cellulose and hemicellulose in Eucommia ulmoides leaves obviously decreased after Trichoderma viride fermentation. The optimum parameters were listed as follows: solid-liquid ratio of 0.06 g/mL, four extraction times, extraction time of 89.72 min, and extraction temperature of 85 °C. The actual yield of gutta-percha was 4.38%. The amount of extraction solvent per unit weight of gutta-percha from untreated Eucommia ulmoides leaves was 2.91 mL/mg, while that from leaves treated by Trichoderma viride was only 0.96 mL/mg. The amount of extraction solvent was grossly reduced, which is beneficial in terms of environmental protection. The characterizations of gutta-percha were verified by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and proton nuclear magnetic resonance (¹H NMR). This study laid a certain theoretical and experimental basis for the multi-stage extraction of Eucommia ulmoides leaves and the utilization of Eucommia ulmoides resources.

Evaluation of surface analysis of gutta-percha after disinfecting with sodium hypochlorite, silver nanoparticles, and chitosan nanoparticles by atomic force microscopy: An in vitro study

Aims and Objectives:

The purpose of this study is to evaluate the surface topography of gutta-percha (GP) after disinfecting with sodium hypochlorite (NaOCl) (5.25%), silver nanoparticles (AgNPs) (70 µg/ml), and chitosan nanoparticles (ChNPs) (1.5 mg/ml) by atomic force microscopy (AFM).

Materials and Methods:

Forty GP cones were taken in this in vitro study. These samples were divided into four different groups such as Group I – control group (untreated GP Points) and Group II, III, and IV were treated with 5.25% NaOCl, 70 µg/ml AgNPs, and 1.5 mg/ml ChNPs, respectively. The surface topography analysis of the samples was performed using AFM.

Statistical Analysis:

Root mean square (RMS) and surface roughness parameters were used to compare the structure of GP points with contact mode imaging. These values were tested by IBM SPSS-20.0 version statistical software using one-way ANOVA and post hoc (Tukey's honestly significant difference) tests. They were considered statistically significant when P < 0.05.

Results:

The RMS and surface roughness values are significantly higher for NaOCl group (5.25% NaOCl) when compared with AgNPs group (70 µg/ml AgNPs) and ChNPs group (1.5 mg/ml ChNPs).

Conclusion:

This study has shown more surface topography deterioration of GP treated with NaOCl and lesser deterioration with AgNPs and ChNPs which affects postoperative prognosis.

The investigation of thermal behaviour and physical properties of several types of contemporary gutta-percha points

Aim

To analyse the contents and thermal behaviour of several brands of contemporary gutta‐percha points due to the variable nature of the components of gutta‐percha, and the impact they can have on the physical properties of this unique material during canal filling.

Methodology

Six brands of gutta‐percha were investigated: Conform Fit ^TM Gutta‐Percha Points for ProTaper Gold® (PTG) (Dentsply Sirona), ProTaper® Universal Gutta‐Percha Points (PTU) (Dentsply Sirona), Autofit ^TM Feathered Tip Gutta Percha (Kerr), Mtwo® Gutta‐Percha (VDW), Gutta Percha Root Canal Points (GC, GC Corporation) and Gutta‐Percha Points ISO Color‐Coded (ISO; Dentsply Sirona). The organic and inorganic fractions of gutta‐percha points were separated by quantitative chemical analysis. Thermal conductivity was detected using a laser flash method. In addition, the thermal behaviour of gutta‐percha in response to temperature variations was analysed using differential scanning calorimetry (DSC). Kruskal–Wallis and Dunn tests were applied for comparisons amongst groups for chemical compositions and temperature obtained from DSC. The associations between compositions and thermal conductivity were determined using simple linear regression. A p value <.05 was considered to be statistically significant.

Results

There were significant difference in the inorganic fractions of the gutta‐percha points in percentage by weight amongst the groups (p < .05). PTG had the lowest thermal conductivity (0.42 W/m K). A positive correlation was observed between the percentage of inorganic fraction and thermal conductivity (r = 0.95). The initial phase changing temperature and peak temperature measured by DSC were significantly different when the β‐form transformed to α‐form (p < .05), whereas no significant difference was found during the α‐form to the amorphous‐phase transition (p > .05).

Conclusions

Chemical compositions and initial phase changing temperature by DSC varied according to the various brands of gutta‐percha points. Conform Fit ^TM gutta‐percha had the lowest percentage of inorganic fraction and thermal conductivity amongst these six brands of gutta‐percha. Thermal conductivity had the strongest positive correlation with the percentage of inorganic components and zinc, whilst there was a negative correlation to the amount (ratio) of gutta‐percha.

Methodological proposal for evaluation of adhesion of root canal sealers to gutta-percha

AIM

To compare the bond strength of an epoxy resin-based sealer and two calcium silicate-based sealers (CSS) to gutta-percha discs using a new method.

METHODOLOGY

Round discs of gutta-percha (n = 60), measuring 10 mm in diameter and 2 mm in thickness, were placed on a glass plate and a drop of each sealer (AH Plus, EndoSequence BC Sealer and EndoSeal MTA) was placed on their surface. Another identical disc was placed onto the first one and a standardized weight (0.0981 N) applied over them using a specially developed apparatus. Ten samples prepared for each sealer were submitted to a microshear bond strength test accomplished by a specially designed set-up coupled to a universal testing machine. The Kruskal-Wallis test followed by a post hoc procedure was used to compare groups considering the preliminary analysis of the raw data had indicated the nonadherence to a Gaussian distribution (Shapiro-Wilk, p < .05). Alpha error was set at 5%.

RESULTS

Overall, no premature failure occurred. All sealers had some degree of adhesiveness to gutta-percha discs but with a significant difference amongst them (Kruskal-Wallis, p = .019). The epoxy resin-based sealer (AH Plus) had significantly higher median shear bond strength values (1.43 MPa; 1.40-1.83) compared to EndoSeal MTA (0.53 MPa; 0.46-0.73) (p = .021) and EndoSequence BC Sealer (0.45 MPa; 0.34-0.46) (p = .023), whilst the lowest median value was observed with EndoSequence BC Sealer (0.45 MPa; 0.34-0.46) (p < .05).

CONCLUSIONS

CSS sealers had weaker bonding to gutta-percha when compared to the epoxy resin-based AH Plus sealer. The proposed methodology is an innovative and reproducible method for testing the bond strength of root canal sealers to gutta-percha.

Retreatment in endodontics with plastic core obturators. A new technique

The aim of this study was to present a new technique for plastic carrier removal in retreatment situations. The gutta-percha technique that uses plastic carrier obturators is one of the most commonly used; however, removing this core is tedious and time-consuming. Two clinical cases were performed by an expert in the field of endodontics, to expose this technique, in which a conical ultrasonic tip with an active point and a Hëdstrom hand file allowed the removal of the plastic carrier quickly and effectively. The use of magnification is indispensable for a predictable success with this method.

Evaluation of Antibacterial Properties of Organic Gutta-percha Solvents and Synthetic Solvents Against Enterococcus faecalis

Background:

The use of solvents is necessary to remove remnants of filling materials within dentinal tubules to allow penetration of irrigating solution within the tubules.

Aim and Objectives:

We aimed at determining the antibacterial effect of various gutta-percha (GP) solvents against Enterococcus faecalis (E. faecalis).

Materials and Methods:

An in vitro study was conducted by measuring the zone of inhibition using the disk diffusion method. The test organism used for the study was E. faecalis, and the solvents were divided into five groups: eucalyptus oil, chloroform, turpentine oil, xylene, and orange oil. About 500 μL of the suspension was spread over the agar plates, and the empty sterilized disks were impregnated with 10 μL of pure essential oils (EOs). The inoculated plates were incubated at 37°C for 18 to 24 h. The antimicrobial activity of each solvent was expressed and measured in terms of the mean diameter of the zone of inhibition (in mm) produced by each solvent at the end of the incubation period. ANOVA was used for intergroup comparison. The P-value of <0.05 was considered significant.

Results:

The mean zone of inhibition for E. faecalis was 24.00 ± 1.21 for eucalyptus oil, 16.30 ± 0.92 for chloroform, 26.50 ± 1.24 for turpentine oil, 13.70 ± 1.26 for xylene, and 19.80 ± 1.32 for orange oil. The difference between the groups was statistically significant (P < 0.001).

Conclusion:

This study demonstrated that the use of turpentine oil during endodontic retreatment significantly reduced the levels of E. faecalis as compared with other solvents.

Evaluation of remaining dentin thickness around the prepared root canals and its influence on the temperature changes on the external root surfaces during different heated gutta-percha obturation techniques

Context

Temperature rise on external root surface has a deleterious effect on the periodontium.

Aims

To compare and evaluate the temperature changes on the external root surfaces using three different heated gutta-percha obturation techniques and also to evaluate the effect of remaining dentin thickness (RDT) on the temperature rise during obturation.

Settings and Design

In vitro study with a customized temperature measurement setup.

Materials and Methods

Thirty decoronated human maxillary central incisors were cleaned and shaped using standardized method. RDT was measured using cone beam computed tomography. They were divided into three groups of 10 samples each. Group 1 was obturated by traditional warm vertical compaction, Group 2 using solid core obturation, and Group 3 by warm vertical compaction technique using GP heater in vibration mode. AH Plus sealer was used as cement sealer. During obturation, the temperature rise was measured using K-type thermocouples in the coronal, middle, and apical thirds. The highest temperature rise during the procedure was recorded.

Statistical Analysis Used

Data were analyzed by one-way analysis of variance and post hoc Tukey's test.

Results

Traditional warm vertical compaction had the highest temperature change followed by warm vertical compaction using GP heater in vibration mode and solid core obturation.

Conclusion

There was a temperature rise on external root surfaces in the three techniques evaluated. Solid core obturation technique showed the least temperature change. There was no significance in the effect of RDT on temperature rise during obturation.

Management of Ductal Sialolith Simplified: A New Technique

Sialolithiasis is a common salivary gland disease. It may cause swelling of the gland, infection of the gland, or even death of glandular parenchymal cells. Various treatment modalities are available for management of sialolithiasis such as extracorporeal shock wave lithotripsy, sialoendoscopy, laser intracorporeal lithotripsy, interventional radiology, the video-assisted conservative surgical removal of the parotid, and submandibular calculi. These sophisticated procedures may not be available in all health-care centers. In this article, a new simple yet precise technique for management of ductal sialolith with minimum armamentarium is introduced.

The use of solvents for gutta-percha dissolution/removal during endodontic retreatments: A scoping review

This scoping review study aimed to map the evidence about solvents' use for gutta-percha dissolution and removal during endodontic retreatments. The study protocol followed the Joanna Briggs Institute guidelines, available online (https://osf.io/5vy8n/). Reporting was based on PRISMA Extension for Scoping Reviews. We selected dentistry studies that considered the effectiveness of solvents in gutta-percha dissolution in endodontic retreatments and compared their performance to the use of instrumentation techniques without solvents. The search and study screening were performed in PubMed and Scopus databases by two independent researchers. A descriptive analysis considered the study design, method/technique used for obturation, method/technique used for instrumentation during retreatment, solvent solutions tested, exposure time, and main findings. A total of 41 studies were included. Despite that, most studies suggested that solvents' use may complicate root canal cleanliness, regardless of the type of instrumentation used, and facilitate the presence of gutta-percha remnants in the root surface. Thus, the use of solvents should be avoided and its use should only be considered if the previous working length was not possible to access without it. Despite that, high heterogeneity was observed, further studies are still encouraged comparing the performance and effects of different solvents in different clinical scenarios.

The effect of tapered master gutta-percha cone on apical seal of straight and curved root canals prepared with nickel-titanium rotary files

BACKGROUND

Gutta-percha has been the predominant root canal filling material which is developed with different taper. Canal obturation fixed with nickel-titanium (NiTi) instruments and tapered gutta-percha master cone and lateral condensation is advantageous because it is clinically effectual and appears to result in a radiographically acceptable outcome. The aim of this in vitro study was to determine the effect of tapered master gutta-percha cone on apical seal of straight and curved root canals using NiTi rotary files.

MATERIALS AND METHODS

In this in vitro study total of 130 mandibular molars were selected and divided into six experimental groups (n = 20) based on the degree of root canal curvatures (0°-20°and 20°-40°) and the taper of master cones (0.02, 0.04, and 0.06). The roots were immersed in the bacterial leakage model and monitored daily for a period of 70 days. Data were analyzed using Kaplan-Meier approach, log-rank test, and Chi-square tests. P < 0.05 was considered statistically significant.

RESULTS

The microleakage in the 0°-20° canal curvature using 0.02- and 0.04-tapered master cones was similar and considerably <0.06-tapered master cone (P < 0.05). However, the microleakage in the 20°-40° canal curvature using 0.02- and 0.04-tapered master cones was more than 0°-20° and for 0.06-tapered master cone was <0°-20°, but there was no statistical difference between the use of 0.02-, 0.04-, and 0.06-tapered master cones (P > 0.05).

CONCLUSION

The lateral condensation filling technique using 0.02- and 0.04-tapered master cones is more effective in minimizing microbial leakage in straight canals than 0.06-tapered master cone.

Effect of Sonic Agitation of a Binary Mixture of Solvents on Filling Remnants Removal as an Alternative to Apical Enlargement-A Micro-CT Study

BACKGROUND

This work aimed to evaluate the efficacy of sonic agitation of a binary mixture of solvents (methyl ethyl ketone/tetrachloroethylene) on filling remnants removal and compare the effects of solvent agitation with the enlargement to the next instrument size.

METHODS

Twenty-four mandibular incisors were prepared with ProTaper Next (X1, X2) and obturated with the single-cone technique and AH Plus sealer. The teeth were retreated with ProTaper Universal Retreatment and ProTaper Next and divided into two groups (n = 12) according to the final instrument (X3 or X4). All canals were submitted to a supplementary procedure consisting of a mixture of solvents-methyl ethyl ketone/tetrachloroethylene, agitated with EndoActivator. The volume of filling remnants was assessed through micro-computed tomography in the apical 5 mm. Statistical analysis was performed with a significance level of 5%.

RESULTS

The supplementary procedure of agitation of the solvent mixture was beneficial in both groups (p < 0.05). There were no statistically significant differences between canals re-prepared until X4 and canals re-prepared until X3 plus solvent (p > 0.05).

CONCLUSIONS

An additional step with a two-solvent solution potentiated by EndoActivator showed to be very effective for the removal of gutta-percha and resinous sealer remnants from apical root canals of mandibular incisors, avoiding further enlargement.

Efficacy and Cytotoxicity of Binary Mixtures as Root Canal Filling Solvents

OBJECTIVES

This study reports the efficacy of two solvent mixtures on the dissolution of gutta-percha and AH Plus sealer, together with the cytotoxicity.

METHODS

Methyl ethyl ketone (MEK), orange oil, tetrachloroethylene, MEK/tetrachloroethylene (1:1), MEK/orange oil (1:1), and chloroform (control) were tested. Twelve groups (n = 15) of standardized stainless-steel molds filled with softened gutta-percha cones and twelve (n = 15) filled with AH Plus were immersed in the corresponding mixture or individual solvent, in an ultrasonic bath, for either 2 or 5 min. The effect of the solvents was assessed qualitatively by a topographical analysis (scanning electron microscopy) and chemical analysis (Fourier transform infrared spectroscopy), and quantitatively by a weight loss and viscoelastic property (dynamic mechanical analysis) evaluation. The cytotoxicity was assessed on MG63 human osteoblastic cells.

RESULTS

The mixtures did not show the formation of new compounds. Both presented significantly higher efficacies compared to their individual solvents, suggesting a synergistic effect. Their dissolution efficacy was similar to that of chloroform, showing high cytocompatibility.

CONCLUSIONS

The proposed strategy, incorporating ultrasound agitation and profiting from the synergy of adequate solvents, might enhance root canal cleanliness allowing a single-step procedure to dissolve gutta-percha and the sealer remnants, while assuring cytocompatibility with the periapical tissues.

Decontamination of Gutta-percha Cones employed in Endodontics

The gutta-percha cones used in endodontic treatment are produced in aseptic conditions and their composition includes zinc oxide, which is responsible for antibacterial activity. However, there is the possibility of microbial contamination by manipulation, aerosol or during storage. Although several chemical agents have been tested for their decontamination, there is no consensus on the best disinfection protocol to be used. The aim of this study was to evaluate the decontamination of gutta-percha cones contaminated with the bacteria Enterococcus faecalis, by using chlorhexidine digluconate (CHX) and sodium hypochlorite (NaClO) at different concentrations for short exposure times. For this purpose, gutta-percha cones (size 40) were selected at random from a sealed box and immersed for 1 min in a microbial suspension. Then they were immersed in specific Petri dishes for different groups containing: CHX 2%, NaClO 1% or NaClO 2.5% for 30 s or 1 min, and subsequently placed in tubes containing BHI broth. After incubating the tubes for 48 h, it was observed that 1% and 2.5% NaClO and 2% CHX were effective for decontaminating the cones at those exposure time intervals. Microbial growth was detected in one of the replicates of the group with CHX applied for 30 s. To prevent the possibility of failures at this stage, the exposure time of gutta-percha cones to the decontaminating agent should not be reduced.

[Assessment of the efficiency of root canals sealing depending on the type of root dentin treatment (experimental study)]

Research objective was a comparative assessment of quality of sealing of root canals, subjected to a standard method of processing, processing by the laser and processing by LAI equipment, with sealer and the gutta-percha. The study included 20 teeth extracted because of chronic periodontitis and divided into four groups. Root canals were processed according to the traditional protocol using as an irrigant 3% NaOCl and 17% EDTA solution, LAI equipment, the Er laser; Cr; YSGG 2780 nm at a power 1W and 1,5W and sealed up using single protocol by means of an epoxy siler of AH+ and gutta-percha by continuous wave by means of the CalamusDual (DentsplayMaillefer) device. Scanning electronic microscopy was used to study the efficiency of sealing depending on a type of processing. The highest sealing of the obturation material to the canal walls was revealed in teeth processed by the laser at a power of 1.5 W confirmed by lack of emptiness between a material and a dentine. Conventional irrigation protocol did not result in an optimal obturation with the extent of empty spaces up to 13 microns. The results of the pilot research are the basis for more extensive studies.

Shear bond strengths of calcium silicate-based sealer to dentin and calcium silicate-impregnated gutta-percha

AIM

To compare the shear bond strengths of a calcium silicate-based root canal sealer (CSS), to dentin or calcium silicate-impregnated gutta-percha (CSGP), with the shear bond strengths of an epoxy resin-based sealer.

METHODS

For sealer/dentin testing, 40 hemisectioned roots were divided into 2 groups. Coronal root dentin discs were bonded with CSS or epoxy resin-based sealer. For sealer/core material testing, CSGP and conventional gutta-percha discs were bonded with a matching sealer (N = 20 per group). The shear bond strengths were tested using a universal testing machine. The failed modes were analyzed using stereomicroscopy and scanning electron microscopy.

RESULTS

The CSS sealer had significantly higher shear bond strength to dentin than did epoxy resin-based sealer (P < .01). However, shear bond strengths of the 2 sealers to core materials did not significantly differ (P = .74). The remnants of the CSS sealer adhering to dentin or calcium silicate gutta-percha disc were observed.

CONCLUSIONS

The CSS sealer had better adhesion to dentin than did epoxy resin-based sealer. However, the bond of the CSS sealer to impregnated gutta-percha was not superior to the epoxy resin-based sealer bonded to conventional gutta-percha.

Characterization of the latex clearing protein of the poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene) degrading bacterium Nocardia nova SH22a

Nocardia nova SH22a is an actinobacterium capable of degrading the polyisoprenes poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene). Sequencing and annotating the genome of this strain led to the identification of a single gene coding for the key enzyme for the degradation of rubber: the latex clearing protein (Lcp). In this study, we showed that Lcp_SH22a-contrary to other already characterized rubber cleaving enzymes-is responsible for the initial cleavage of both polyisoprene isomers. For this purpose, lcp_SH22a was heterologously expressed in an Escherichia coli strain and purified with a functional His₆- or Strep-tag. Applying liquid chromatography electrospray ionization time-of-flight mass spectrometry (LC/ESI-ToF-MS) and a spectrophotometric pyridine hemochrome assay, heme b was identified as a cofactor. Furthermore, heme-associated iron was identified using total reflection X-ray fluorescence (TXRF) analysis and inhibition tests. The enzyme's temperature and pH optima at 30°C and 7, respectively, were determined using an oxygen consumption assay. Cleavage of poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene) by the oxygenase was confirmed via detection of carbonyl functional groups containing cleavage products, using Schiff's reagent and electrospray ionization mass spectrometry (ESI-MS).

A fungal ball within a maxillary sinus with dental root canal filler and rare fungal propagules

A fungal ball of a maxillary sinus sometimes includes dental treatment-related foreign material because the sinus is close to the root of the upper teeth. We present a case of right maxillary sinus fungal ball with a gutta-percha point, a dental root canal filler. X-ray analysis of the foreign material in the paraffin section of the fungal ball successfully detected zinc, sulfur, and barium, all of which were constituents of the gutta-percha point. The gutta-percha point might have facilitated the formation of the fungal ball through disruption of the sinus-clearing mechanism. Another interesting histological feature of the fungal ball was the finding of calcium oxalate crystals and non-hyphal fungal elements such as cleistothecia, Hülle cells, and conidial heads. This is the first report of such a combination being found in a specimen of human fungal disease. Although fungal culture was not available in the present case, molecular analysis of the formalin-fixed paraffin-embedded tissue of the fungal ball succeeded in revealing only DNA sequences of Aspergillus nidulans and some other environmental Aspergillus spp.

Gutta-percha in endodontics - A comprehensive review of material science

The complete and three-dimensional fluid tight seal of the root canal system is the final component of the endodontic triad. The long-standing and closest material which has fulfilled this criterion is gutta-percha (GP). Several materials have been tried and tested as an endodontic filling material, of which GP has been most extensively used for years and has established itself as a gold standard. In addition, it has proved itself successful with different techniques of obturation while maintaining its basic requisites. This article deals briefly with the history and evolution of GP, source, chemical composition, manufacturing, disinfection, cross-reactivity, and advancements in the material.

Chronic sinusitis of odontogenic origin due to an undiagnosed displaced root fragment in the maxillary sinus and the role of cone beam computed tomography in successful management

Radiographic imaging is an important criteria in diagnosis, treatment planning, and follow-up of an endodontic treatment. When clinicians encounter with diagnostic difficulties and persistent symptoms, the need for advanced diagnostic aids, especially imaging methods, become imperative and essential. This paper reports a case, in which primary endodontic therapy having failed, the patient had persisting symptoms such as pain, swelling, and draining sinus along with signs and symptoms of maxillary sinusitis. Advanced diagnostic aids such as Cone Beam Computed Tomography was useful in accurate identification of the etiology, which was a fractured mesiobuccal root tip of maxillary molar. This is the first reported case, in which the fractured root tip has migrated to the maxillary sinus, during primary endodontic treatment, through the perforated antral floor causing odontogenic sinusitis. The operating microscope helped in the successful completion of endodontic retreatment along with fractured root fragment retrieval.

Long-term Outcomes of Endodontic Treatment Performed with Resilon/Epiphany

INTRODUCTION

Resilon (Resilon Research LLC, Madison, CT) with Epiphany Sealer (Pentron Clinical Technologies, Wallingford, CT) was introduced into the market in 2004 as a new method of root canal obturation. This material as well as the traditionally used gutta-percha with AH Plus sealer (Dentsply Maillefer, Tulsa, OK) were in use over a 9-year span in the University of North Carolina endodontic clinics. Although Resilon was initially thought to create a "monoblock" seal between the material and the canal, in vitro studies later suggested this concept not to be true. The long-term outcome of Resilon using a validated radiographic index and a systematic approach has not been reported. The purpose of this retrospective cohort study was to radiographically evaluate the outcome of Resilon/Epiphany-treated root canals compared with traditional gutta-percha/AH Plus.

METHODS

One hundred twenty-five teeth were radiographically evaluated using the periapical index; 80 were treated with Resilon and 45 with gutta-percha. Age, sex, tooth position, and number of months to follow-up were documented, and a multivariate analysis with odds ratio was performed.

RESULTS

Resilon-treated teeth were 5.3 times more likely to have a periapical index of 3 to 5 at follow-up compared with gutta-percha (P = .009). Teeth presenting with preoperative lesions, regardless of the material used, were also more likely to present with a lesion at follow-up (P = .04).

CONCLUSIONS

Teeth obturated with Resilon were more likely to present with a lesion at follow-up compared with gutta-percha obturated teeth after controlling for the presence of a preoperative lesion and the length to follow-up.

Comparing the Ability of Different Materials and Techniques in Filling Artificial Internal Resorption Cavities

Objective

This ex vivo study aims to investigate the root filling quality of warm vertical technique, single-cone technique with GuttaFlow2, Endoseal MTA and EndoSequence BC sealer as a sealer in artificial internal resorption cavity.

Methods

For this study, 40 human single-root teeth were selected. After root preparation, the roots were horizontally sectioned 7 mm from the apex. The hemisphere cavities were created on both sides, and then they were re-approximated. According to filling methods and materials, the samples were randomly as-signed to four experimental groups: I: warm vertical compaction technique (WVC), II: single-cone technique with GuttaFlow2 (GF), III: single-cone technique with Endoseal MTA sealer (EM), IV: single-cone technique with EndoSequence BC sealer (ES). Filled roots were radiographed in buccolingual and mesiodistal views to check the obturation, and stored in humid environment at the room temperature for 7 days. Each tooth was sectioned 7 mm from the root apex at the level of the previous cut, and it was then photographed un-der stereomicroscope. The photographs and radiographs of all samples were imported to an image-analysis software to calculate the percentage of sealer, gutta-percha, and voids. The results were statistically analyzed using one-way ANOVA and Kruskal-Wallis Dunn's tests.

Results

In buccolingual view of radiographs, the WVC and EM groups showed significantly lower percent-age of voids (P value<0.05) compared to that in the GF group. In mesiodistal view, the WVC and EM groups showed significantly lower percentage of voids (P value<0.05) compared to that in the GF and ES groups. In stereomicroscope evaluation, the WVC and EM groups showed significantly lower percentage of voids (P value<0.05) compared to that in the GF and ES groups. The differences observed between the WVC and EM groups (P value>0.05) or between the GF and ES groups (P value>0.05) were not significant.

Conclusion

WVC technique and single-cone technique with EM sealer are the optimum methods to fill ar-tificial resorption cavities.

Comparison of the effectiveness of various rotary and reciprocating systems with different surface treatments to remove gutta-percha and an epoxy resin-based sealer from straight root canals

AIM

To compare the Reciproc Blue, Reciproc and ProTaper Universal Retreatment systems with regard to the effective removal of epoxy resin-based sealer and gutta-percha during the retreatment of oval, straight root canals.

METHODOLOGY

Forty-five extracted, human mandibular first premolars with single straight oval canals were selected on the basis of cone beam computed tomography evaluations. The root canals were instrumented with the ProTaper Next system up to the X2 file, and filled with gutta-percha and epoxy resin-based sealer using the cold lateral condensation technique. After 1 month, the samples were randomly divided into three groups (n = 15) according to the retreatment system used: Reciproc Blue R40, Reciproc R40 and ProTaper Universal. The specimens were scanned at the resolution of 1.2 μm by a microcomputed tomography device after the root filling and retreatment procedures, and the decrease in the volume of filling material after each retreatment protocol was measured. The results were analysed using the Kruskal-Wallis test and additional box-and-whisker plots.

RESULTS

Although the volume of the filling material decreased significantly in all three groups (P < 0.05), none of the systems removed the material completely. The Reciproc system removed significantly more material than the ProTaper Universal (P < 0.001) and Reciproc Blue (P = 0.005) systems, with the latter two exhibiting equal volumes of remaining material (P = 0.068).

CONCLUSION

The Reciproc system was more effective than the Reciproc Blue and ProTaper Universal Retreatment systems during the removal of filling material from oval, straight canals, although none of the systems completely removed the filling material.

In vitro evaluation of the contact angle formed between AH Plus, Hybrid Root Seal and mineral trioxide aggregate Plus sealer with dentin and gutta-percha

Aim:

The purpose of this study was evaluation and comparison of the contact angle of new root canal sealers – Hybrid Root Seal, mineral trioxide aggregate (MTA) Plus, and the conventional AH Plus sealer with dentin and gutta-percha.

Materials and Methods:

Two groups (Group D – dentin and Group G – gutta-percha) of 18 samples each were further randomly divided into 3 subgroups based on the type of sealer used, that is, AH Plus, Hybrid Root Seal, and MTA Plus. Contact angle measurement device (Phoenix 300) was used to measure the contact angle of the sealers on both dentin and gutta-percha. The results thus obtained were analyzed using one-way analysis of variance and Student's t-test.

Results:

MTA Plus recorded significantly higher values of contact angle on both the substrates, that is, dentin and gutta-percha when compared to AH Plus and Hybrid root canal sealer. The lowest value of contact angle in gutta-percha and dentin was shown by Hybrid root canal sealer and AH Plus, respectively.

Conclusion:

Both AH Plus and Hybrid Root Seal exhibited lower contact angle values, and hence, better wettability on both dentin and gutta-percha as compared to MTA Plus.

Stress distributions in internal resorption cavities restored with different materials at different root levels: A finite element analysis study

The aim of this study was to evaluate the stresses within simulated roots with internal resorption cavities at the apical, middle and coronal root levels, after obturation with gutta-percha and/or MTA utilising finite element analysis (FEA). Mandibular premolar teeth with internal resorption cavities at different root levels were modelled. Models were restored with gutta-percha and/or MTA. An oblique force of 300 N was applied and stress evaluations were carried out. In the MTA-filled resorption models, the stresses were distributed more homogeneously than the gutta-percha filled models, and the stress concentrations were lower in the remaining dentinal tissues. If the whole root is considered, the fully gutta-percha-filled models generated the highest stress values. Differences between the fully MTA-filled models and hybrid techniques were present only in the apical resorption models. Both the MTA and combination of MTA and gutta-percha can be suggested for use in clinical practice, in cases of internal root resorption cavity obturation.

Comparative evaluation of three different rotary instrumentation systems for removal of gutta-percha from root canal during endodontic retreatment: An in vitro study

Context:

Endodontic retreatment is performed in teeth with endodontic failures. The main goal of retreatment is cleaning and shaping of the root canal with removal of old root filling material. Hand instruments and rotary instruments are mainly used for removing this filling material.

Aim of Study:

To compare the relative efficacy of three rotary instrumentation systems for removal of gutta-percha from root canal during endodontic retreatment.

Objective of Study:

To find out which NiTi system is more efficacious in retreatment and to check out the efficacy of retreatment with and without use of solvent.

Materials and Methods:

Sixty freshly extracted, single-rooted human mandibular premolars were instrumented with K-files, and each root canal was filled with gutta-percha and AH Plus (Dentsply Detrey, Konstanz, Germany) sealer using lateral compaction. Specimens were then divided into three experimental groups with twenty specimens each. Groups were then subdivided into ten specimens each. Groups were then retreated either with or without solvent. The removal of gutta-percha was performed using ProTaper retreatment files, Mtwo retreatment files, and R-Endo files after 2 weeks. The amount of root canal filling material remnant in the coronal, middle, and apical thirds was measured using stereomicroscope and computer image analysis program.

Statistical Analysis Used:

Data were evaluated statistically using analysis of variance.

Results:

ProTaper group was found to have less remnant filling material as compared to the other groups in coronal and middle thirds, but a significant difference was observed between ProTaper and Mtwo and Mtwo and R-Endo in the nonsolvent groups (P < 0.05). Mtwo group demonstrated less amount of remaining filling material in the nonsolvent group.

Conclusions:

Both nickel–titanium systems and ProTaper and Mtwo retreatment file systems, were found to be effective in the removal of root canal filling material. However, complete removal of gutta-percha from root canals did not occur with any of the experimental groups.

Surface analysis of gutta percha after disinfecting with sodium hypochlorite and silver nanoparticles by atomic force microscopy: An in vitro study

BACKGROUND

Sodium hypochlorite (5.25% NaOCl) and silver nanoparticles (70 ug/ml AgNPs) have a broad spectrum of antimicrobial efficacy for disinfecting gutta percha (GP) point, so this study was conducted to analyze the assay surface topography of GP when disinfected with AgNPs and 5.25% of NaOCl using atomic force microscopy (AFM).

MATERIALS AND METHODS

In this in vitro study a total of thirty cones were taken. The samples were divided into three treatment groups: Group I and II with 70 μg/ml AgNPs and 5.25% NaOCl. The time duration was 1 min. Untreated GP points served as control group. After treatment of 1 min for each solution, the samples were positioned in the AFM. For comparison, the root mean square (RMS) was used to investigate the structure of the GP points. Unpaired t-test and ANOVA test were used. The differences among the groups were tested by Tukey's honestly significant difference test and were considered significant when P < 0.05.

RESULTS

5.25% NaOCl created RMS value of 202.48 nm at 1 min as compared to 70 μg/ml of AgNPs and control which produced RMS value of 44.48 nm and 24.1 nm, respectively (<0.0001).

CONCLUSION

The study showed irregularity in the surface of GP with NaOCl and lesser deterioration with AgNPs which could affect the postoperative prognosis. In this study, it was found that NaOCl causes 10 times more surface topography deterioration of GP when compared to AgNPs at 700 times lesser concentration.

Management of heat-induced bone necrosis following thermal removal of gutta-percha

Many endodontically treated teeth require a post to improve the retention of the coronal restoration, which necessitates removal of the coronal part of the gutta-percha from the canal by thermal method, among other techniques. However, this technique carries the risk of heat conduction to the attachment unit of the periodontium and infliction of permanent damage especially in cases where the remaining root's dentin walls are thin. The overall objective of this article is to report on the clinical manifestations, histologic description, and periodontal management of three cases of heat-induced damage following thermal removal of gutta-percha.

Cytocompatibility of a self-adhesive gutta-percha root-filling material

Context:

A novel root-filling material based on the incorporation of ultrafine alkaline bioactive glass particles (bioactive gutta-percha, [BGP]) was developed to work without sealer.

Aim:

In the present study, the objective was to verify the in vitro biological response to this material by assessing its cytocompatibility.

Materials and Methods:

Prototypes of BGP were compared to conventional gutta-percha (GP), dense polystyrene beads as a negative control and fragments of latex as a positive control. Extracts of each material were prepared according to ISO 10993-5:2009, and human osteoblast-like cells in primary culture were exposed to all extracts for 24 h. Cell viability was assayed sequentially for three different parameters: mitochondrial activity, membrane integrity, and cell density.

Statistical Analysis Used:

Nonparametric analysis (using Kruskal–Wallis test combined with post hoc Dunn's test) was performed for comparison among groups, with significance established at 5%.

Results:

BGP reduced mitochondrial activity to 62% of control, but presented no toxicity on membrane integrity and proliferation assays. BGP effect on metabolism was dose-dependent and reduced to acceptable levels with dilution.

Conclusion:

The novel GP material presented slight dose-dependent effects on cell metabolism but did not affect cell survival.

Comparative evaluation of fracture resistance of root canals obturated with four different obturating systems

Aim and Objectives

The aim of this study is to evaluate and compare the fracture resistance of root canals obturated with four different obturating systems in endodontically treated teeth.

Materials and Methods

One hundred and twenty single-rooted teeth were selected and decoronated at cementoenamel junction. Instrumentation of teeth (except control group) was done with Mtwo rotary files up to size 25/0.06 using a step-back technique. All teeth were divided into four experimental groups (n = 25) and two control groups (n = 10). In Group I (negative control), teeth were neither instrumented nor obturated, in Group II (positive control), instrumentation was done, but no obturation was performed, in Group III, obturation was done with cold lateral compaction technique, in Group IV, obturation was done with cold free-flow compaction technique, in Group V, obturation was done with warm vertical compaction technique, and in Group VI, obturation was done with injection-molded thermoplasticized technique. All prepared teeth were embedded in an acrylic resin block, and their fracture strength was measured using Universal Testing Machine. Statistical data were analyzed using one-way analysis of variance and Tukey's honestly significant difference test.

Results

Negative control Group I showed highest fracture resistance and positive control Group II had lowest fracture resistance. Among experimental groups, cold free-flow compaction technique with GuttaFlow2 (Group IV) showed higher fracture resistance as compared to the Group III, Group V, and Group VI.

Conclusion

GuttaFlow2 has the potential to strengthen the endodontically treated roots to a level that is similar to that of intact teeth.

Theoretical distribution of gutta-percha within root canals filled using cold lateral compaction based on numeric calculus

This study aimed to present a new method based on numeric calculus to provide data on the theoretical volume ratio of voids when using the cold lateral compaction technique in canals with various diameters and tapers. Twenty-one simulated mathematical root canal models were created with different tapers and sizes of apical diameter, and were filled with defined sizes of standardized accessory gutta-percha cones. The areas of each master and accessory gutta-percha cone as well as the depth of their insertion into the canals were determined mathematically in Microsoft Excel. When the first accessory gutta-percha cone had been positioned, the residual area of void was measured. The areas of the residual voids were then measured repeatedly upon insertion of additional accessary cones until no more could be inserted in the canal. The volume ratio of voids was calculated through measurement of the volume of the root canal and mass of gutta-percha cones. The theoretical volume ratio of voids was influenced by the taper of canal, the size of apical preparation and the size of accessory gutta-percha cones. Greater apical preparation size and larger taper together with the use of smaller accessory cones reduced the volume ratio of voids in the apical third. The mathematical model provided a precise method to determine the theoretical volume ratio of voids in root-filled canals when using cold lateral compaction.

Comparison of Push-out Bond Strength of Gutta-percha to Root Canal Dentin in Single-cone and Cold Lateral Compaction Techniques with AH Plus Sealer in Mandibular Premolars

Background and aims. The single-cone technique has gained some popularity in some European countries. The aim of the present study was to compare the push-out bond strength of gutta-percha to root canal dentin with the single-cone and cold lateral compaction canal obturation techniques.

Materials and methods. The root canals of 58 human mandibular premolars were prepared using modified crown-down technique with ProTaper rotary files up to #F3as a master apical file (MAF) and divided randomly into groups A and B based on canal obturation technique. In group A (n = 29) the root canals were obturated with single-cone technique with #F3(30/.09) ProTaper gutta-percha, which was matched with MAF in relation to diameter, taper and manufacturer; in group B (n = 29) the canals were obturated with gutta-percha using cold lateral compaction technique. In both groups AH plus sealer were used. After two weeks of incubation, three 2-mm slices were prepared at a distance of 2 mm from the coronal surface and push-out test was carried out. Data were analyzed with descriptive statistics using independent samples t-test.

Results. There were statistically significant differences between two groups. The mean push-out bond strength was higher in group B (lateral compaction technique) compared to group A (single-cone technique; P < 0.05).

Conclusion. Use of single-cone technique for obturation of root canals resulted in a lower bond strength compared to cold lateral compaction technique.