Comparative Evaluation of the Removal of Gutta Percha From the Root Canal Using Various Retreatment File Systems With and Without Magnification: An In Vitro Study.

AIM AND OBJECTIVE: The main goal was to compare the efficacy of gutta percha (GP) removal from the root canal using the Neo Endo Retreatment file system, Solite RS3, and ProTaper Universal Retreatment (PTUR) files with and without magnification under a direct operative microscope using stereomicroscopic evaluation. MATERIALS AND METHODS: Sixty single-rooted teeth were randomly assigned to one of three groups after obturation till F2 mastercone with resin sealer: Group 1 (n=20): Neo Endo Retreatment Files, Group 2 (n=20): Solite RS3, Group 3 (n=20): PTUR files. Each group was further separated into two subgroups: Subgroup 1: without magnification (no direct operative microscope) and Subgroup 2: with magnification under a direct operative microscope at 12× magnification. After retreatment, the roots were grooved buccolingually and split into two halves using a diamond disc with the help of a chisel. The samples were examined under a stereomicroscope. Images were captured in a digital camera and analyzed using image analyzing software Image Pro v10 (Media Cybernetics). RESULTS: The Neo Endo retreatment file system had a significantly greater percentage of remaining obturating material than the Solite RS3 Retreatment and PTUR file systems (p<0.05) in both groups with and without magnification. In the group without magnification, Solite RS3 showed a significant difference compared to ProTaper (p<0.05). In the group with magnification, there was no significant difference between the ProTaper Universal retreatment file system and Solite RS3 (p=0.589). Retreatment performed without magnification had more remnant GP when compared to the retreatment procedure performed under magnification of the direct operative microscope. CONCLUSION: Under stereomicroscopic evaluation, the remnant GP was higher in the Neo Endo File System both with and without magnification than in the Solite Retreatment and PTUR file systems. ProTaper showed moderate significance in removing the obturation than Solite RS3 in the magnification group. The Solite RS3 file system performed as efficiently as the PTUR file system.

Research on the Performance and Modification Mechanism of Gutta-Percha-Modified Asphalt.

Presently, there is a significant focus on the investigation and advancement of polymer-modified asphalt that is both high-performing and environmentally sustainable. This study thoroughly examined the performance and modification mechanism of gutta-percha (GP) as a novel asphalt modifier. The investigation was conducted using a combination of macro- and microscopic testing, as well as molecular dynamics simulations. This work primarily examined the compatibility of GP with asphalt molecular modeling. This paper used molecular dynamics to identify the most suitable mixing temperature. Next, the gray correlation theory was used to discuss the most effective method for preparing gutta-percha-modified asphalt (GPMA). The macro-rheological tests and microscopic performance analysis provided a full understanding of the impact of GP on asphalt properties and the process of alteration. The findings indicate that eucommia ulmoides gum (EUG) exhibits good compatibility with asphalt, while sulfur-vulcanized eucommia ulmoides gum (SEUG) does not demonstrate compatibility with asphalt. Both EUG and SEUG enhance the thermal stability and resistance to deformation of asphalt at high temperatures, with SEUG having a particularly notable effect. However, both additives do not improve the resistance of asphalt to cracking at low temperatures. The manufacturing method for EUG-modified asphalt (EUGMA) involves physical mixing, whereas sulfur-vulcanized eucommia ulmoides gum-modified asphalt (SEUGMA) involves physical mixing together with certain chemical processes. This research establishes a theoretical foundation for the advancement of GP as a novel environmentally friendly and highly effective asphalt modification.

Nanostructured ZnO thin film to enhance gutta-percha's adhesion to endodontic sealers.

BACKGROUND: Gutta-percha (GP) combined with an endodontic sealer is still the core material most widely used for tridimensional obturation. The sealer acts as a bonding agent between the GP and the root dentinal walls. However, one of the main drawbacks of GP core material is the lack of adhesiveness to the sealer. ZnO thin films have many remarkable features due to their considerable bond strength, good optical quality, and excellent piezoelectric, antibacterial, and antifungal properties, offering many potential applications in various fields. This study aimed to explore the influence of GP surface's functionalization with a nanostructured ZnO thin film on its adhesiveness to endodontic sealers. METHODS: Conventional GP samples were divided randomly into three groups: (a) Untreated GP (control); (b) GP treated with argon plasma (PT); (c) Functionalized GP (PT followed by ZnO thin film deposition). GP's surface functionalization encompassed a multi-step process. First, a low-pressure argon PT was applied to modify the GP surface, followed by a ZnO thin film deposition via magnetron sputtering. The surface morphology was assessed using SEM and water contact angle analysis. Further comprehensive testing included tensile bond strength assessment evaluating Endoresin and AH Plus Bioceramic sealers' adhesion to GP. ANOVA procedures were used for data statistical analysis. RESULTS: The ZnO thin film reproduced the underlying surface topography produced by PT. ZnO thin film deposition decreased the water contact angle compared to the control (p < 0.001). Endoresin showed a statistically higher mean bond strength value than AH Plus Bioceramic (p < 0.001). There was a statistically significant difference between the control and the ZnO-functionalized GP (p = 0.006), with the latter presenting the highest mean bond strength value. CONCLUSIONS: The deposition of a nanostructured ZnO thin film on GP surface induced a shift towards hydrophilicity and an increased GP's adhesion to Endoresin and AH Bioceramic sealers.

Revamping the Perished: The Management of Internal Tooth Resorption.

Root resorption is a challenging endodontic case in terms of the management of both hard and soft tissues in patients. It requires thorough knowledge, the proper choice of material, and regular follow-ups. Several etiological factors are responsible for the susceptibility of the tooth to resorption. The most common are dental caries and trauma. This case report sheds light on the etiopathogenesis of the development of internal root resorption and the clinical management of the resorptive defect. It also focuses on the need for proper diagnostic methodology for treating such complex defects.

Comparative evaluation of the antibacterial activity of curcumin-coated gutta-percha versus nanocurcumin-coated gutta-percha against Escherichia coli: An in vitro study.

Introduction: Due to its biological and antibacterial qualities, many plants, including curcumin, are used as phytomedicines in dentistry. They are primarily used as intracanal medication in endodontics to prevent probable chemical side effects and also to address antimicrobial resistance. Curcumin nanoformulations have improved antibacterial activity and improved dispersion, making them the superior form of curcumin. The purpose of this study was to assess curcumin and nanocurcumin's antibacterial properties. As a gutta-percha coating, they are to be tested against Escherichia coli. Materials and Methods: The study employs the standard strain of E. coli, ATCC 25922. The antibacterial activity of gutta-percha cones against E. coli is assessed after coating them with suspensions of curcumin and nanocurcumin. Scanning electron microscopy is utilized to evaluate the coatings' continuity. Results: The gutta-percha cones that are untreated, coated with curcumin, and coated with nanocurcumin exhibit significantly different levels of antibacterial activity. There is statistically significant variation in their antibacterial activity. Conclusion: (1) Compared to curcumin-coated and untreated gutta-percha cones, those coated with nanocurcumin exhibit a stronger antibacterial activity. (2) Compared to uncoated gutta-percha cones, gutta-percha cones coated with curcumin exhibit more antibacterial action.

Non-surgical Endodontic Management of Multiple Mishaps: A Case Report.

The description of non-surgical retreatment is to eliminate all previous filling materials and correct any mishaps. An adequate understanding of root and canal morphology is a fundamental requirement for obtaining a favorable outcome in endodontic treatment. The endodontic diagnosis was previously treated through therapy with symptomatic apical periodontitis. Treatment was performed under a dental operative microscope. Gates Glidden (GG) drills size 2 and 3 were used to remove the coronal part of gutta-percha for all canals. A braiding technique with a Hedstrom file size 15 without a solvent was used to remove gutta-percha and separate the file together for the palatal canal whereas the mesiobuccal canal was retreated by ProTaper Retreatment Kit. Proper understanding of root canal morphology and using an endodontic armamentarium could reduce endodontic mishaps. This case report described the successful management of overextended gutta-percha, a separated file, and a missed canal.

Comparative Evaluation of Solite RS3 and HyFlex Remover Retreatment Files in Conserving Remaining Dentin Thickness During Endodontic Retreatment Using Cone Beam Computed Tomography: An In Vitro Analysis.

Introduction Non-surgical retreatment is seen as a conservative choice for dealing with recurrent infections, instead of opting for periapical surgery. The retreatment processes should be promptly and efficiently carried out, utilizing a suitable armamentarium. The objective of this experiment is to evaluate the quantity of root dentin that remains following the removal of gutta-percha (GP) from the root canal employing two distinct retreatment files. Materials and methods Sixty single-rooted teeth were selected for the examination. The process of shaping and cleaning was performed using the step-back approach, with a master apical file size of 40. The smear layer was effectively eliminated by rinsing with a solution of 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Paper points were employed to desiccate the canals. The obturation process involved the utilization of the lateral compaction technique with the AH Plus sealer (Dentsply Sirona, NC, USA). The teeth were classified into two groups: Group I (n=30) underwent retreatment using HyFlex Remover (Coletene India, Pvt., Ltd.), whereas Group II (n=30) received therapy with Solite RS3 retreatment files (Solite Dental in Chennai, India). The remaining dentin thickness (RDT) was assessed by cone beam computed tomography at levels 3, 6, and 9 mm from the cemento enamel junction after the removal of GP. The acquired data underwent examination using an independent t-test to determine statistical significance. Results The findings demonstrate that the utilization of Solite RS3 files led to a higher level of dentin thickness remaining at 3 mm, 6 mm, and 9 mm on the mesial side in comparison to HyFlex Remover retreatment files. The observed difference was found to be statistically significant at a significance level of p<0.05 on the mesial side. Nevertheless, there was no notable disparity seen between the two file types at these three levels on the distal side (p>0.05). Conclusion Based on the obtained results of the study, it can be concluded that Solite RS3 files show promise in preserving the RDT. However, further studies encompassing diverse parameters are needed to establish a conclusive and definitive conclusion.

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.

Sealing Ability Comparison of Three Different Obturating Systems to Intraradicular Dentin-An In Vitro Stereomicroscopic Study.

Background: Different obturation techniques are being used to improve canal sealing, thereby minimizing marginal leakage. Aims and Objectives: To evaluate the marginal leakage of three different obturating materials and techniques using stereomicroscope. Materials and Methods: Thirty freshly extracted maxillary anterior teeth were collected and were divided into three groups of 10 each for which the biomechanical preparation was done. The teeth were divided into three experimental groups according to the obturation material and technique used, Group I: gutta-percha with AH Plus root canal sealer (lateral condensation): Group II: thermoplasticized gutta-percha technique-non-carrier-based (calamus) with AH Plus sealer (backfill): Group III: C point (self-sealing root canal obturating system) with bioceramic sealer (single cone). Each specimen was subjected for testing apical sealing ability. The values of microleakage associated with different root canal sealers were evaluated using a stereomicroscope. Results: There was no statistically significant difference in the mean scores of apical dye penetration/leakage among all the three groups (P = 0.091), whereas Group I showed a higher degree of apical leakage than the other techniques tested. Conclusion: None of the tested filling materials provided a gap-free or void-free root canal filling; however, thermoplasticized gutta-percha is used with AH Plus sealer exhibited less voids and gaps when compared to other tested materials.

Comparative Analysis of the Efficacy of Various Retreatment File Systems in the Removal of Gutta-Percha in Retreatment Cases and Time Taken During the Procedure: An In Vitro Cone Beam CT Study.

Background Removing gutta-percha manually can be a challenging task, especially when addressing densely packed root-filling material, particularly in cases where resin-based sealers are employed for obturation. The use of nickel-titanium (NiTi) rotary instruments not only effectively shapes the root canal but also efficiently removes the endodontic filling from the curved canal during retreatment. Hence, incorporating rotary NiTi instruments in retreatment cases can alleviate fatigue for both patients and operators. Objectives This study aims to compare the efficacy of Neo-Endo retreatment files, R-Endo retreatment files, and K and H files in the removal of endodontic filling material. Additionally, the remnants of gutta-percha in root canals are evaluated using cone beam computed tomography (CBCT). Materials and methods A total of 60 extracted first maxillary molar teeth were selected for this study. Canal preparation was conducted using the step-back method up to an apical size of 40 K-file. The obturation process involved the use of gutta-percha points and AH Plus sealer in a lateral compaction technique. Post-operative CBCT scans were taken. The samples were randomly divided according to the retreatment files used: group I included Neo-Endo retreatment files, group II included R-Endo retreatment files, and group III included conventional K-files and Hedstroem files (H-Files). The retreatment procedure was considered complete when the last instrument easily reached the working-length range and was physically clean. A stopwatch was used to record the time taken by each file to remove the obturating material. T1 represented the total time (including irrigation and change of file) required to reach the apex, while T2 indicated the complete removal of materials from the canal with the last instrument. The overall time recorded (TT) was calculated as T1 + T2. The removal process was analyzed with CBCT scans. Results The Neo-Endo retreatment files removed the filling materials better and more quickly than the other files. Conclusions Despite the presence of residual filling material in all samples, the Neo-Endo retreatment files left the least amount of residual filling material and achieved the shortest completion time.

Assessment of dental students' knowledge and performance of master gutta-percha cone selection and fitting during root canal treatment: a pilot study.

BACKGROUND: Misconceptions should be detected early in dental students' training to improve their clinical performance. Accordingly, this study aimed to assess undergraduate dental students' knowledge and performance of master gutta-percha (GP) cone selection and fitting during clinical endodontic courses at the College of Dentistry, King Saud University. METHODS: Ninety-nine undergraduate dental students completed an online survey about their knowledge of master GP cone selection. Forty-five of these students were observed by faculty members in clinical endodontic courses while they fitted master GP cones during root canal treatments. The observers recorded the details of each student's cone-fitting techniques. The data were analysed using t-tests, one-way analysis of variance, and chi-square tests (p < 0.05). Inter- and intra-observer reliability were tested using Fliess' Kappa. RESULTS SURVEY: All participants had good knowledge of over-extended cone management, while 80.8% knew how to properly manage a short cone. The proper flaring assessment method was selected by 86.9% of the female and 34.2% of the male students, and this difference was statistically significant (p = 0.0001). OBSERVATION: The students labelled the working length on the master GP cone with an indentation in 64.4% of the cases and by bending the cone 35.6% of the time. Of all students, 84.4% encountered an apical stop, and this rate correlated significantly with the length of the cone on the master apical cone radiograph (p = 0.001). Improper shaping of the canal was the most common cause of ill-fitting cones (83.3%), while 16.7% of the students chose the wrong cone size. The final obturation length was adequate in 80% of the cases; 57.8% of the students were helped by instructors. CONCLUSIONS: Most students had the basic knowledge required to solve problems related to the selection of master GP cones. However, in the clinical setting, more than half of the students required the assistance of an instructor to adjust their cone's fit. The presence of an apical stop had the most significant effect on the length of the fitted master GP cone on radiography. The most common cause of ill-fitting master cones was improper shaping of the canal.

Mental Nerve Neurectomy: A Comparison of Titanium Screw Versus Gutta-Percha Oburation of the Mental Foramen.

OBJECTIVE:  This study aims to compare the two mental foramen obturating techniques in parameters like operator's ease, postoperative displacement of obturation material, and remission of pain after peripheral neurectomy in patients with trigeminal neuralgia. STUDY DESIGN:  This study adopts a single-centered comparative analytical approach. PLACE AND DURATION OF STUDY: This study was performed in the Department of Oral and Maxillofacial Surgery, Armed Forces Institute of Dentistry (AFID), from October 1, 2023, to February 10, 2024. METHODOLOGY: Sixty patients fulfilling the inclusion criteria were included and divided into two groups (30 each), and peripheral neurectomy was performed under local anesthesia. In one group, gutta-percha sticks were used to obturate the foramina, and in the other group, titanium screws were used. Postoperatively, the operator's ease, postoperative displacement, and relapse of pain were recorded. RESULTS:  Titanium screws were easy to handle, and there was no relapse of pain because of no displacement postoperatively when compared with gutta-percha sticks, which were hard to manipulate and showed a relapse of pain. CONCLUSIONS:  Titanium screws have better postoperative outcomes when compared with gutta-percha sticks in terms of the operator's ease, relapse of pain, and postoperative displacement.

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.

Impact of low-fusion gutta-percha cones used in variations of the continuous wave condensation technique with filling sealers based on bioceramic compounds on the quality of root canal filling.

To evaluate the impact on the quality of filling with of low-fusion and conventional gutta-percha cones. Thirty-six maxillary canines were prepared and divided into three groups: I-conventional cone with Downpack at 200 °C at 4 mm from the WL; II-low-fusion cone with Downpack at 100 °C up to 4 mm from the WL; III-low-fusion cone with Downpack at 100 °C up to 7 mm from the WL. Temperature variations were measured in thirds on the external surface of the root. The bond strength was evaluated using the push-out test. The adhesive interface was analyzed by scanning electron microscopy. The bond strength and the temperature variation data were analyzed using analysis of variance and the failure type using the chi-square test. The low-fusion cone group with 7 mm Downpack showed higher bond strength (4.2 ± 2.7) compared with conventional cones (2.8 ± 1.6) and low-fusion cones with 4 mm Downpack (2.9 ± 1.6) (p < 0.05), with occurrence of a higher number of adhesive failures to the filling material and mixed failures. Relative to temperature variation, there was less temperature change in the apical third, in the low-fusion cone with Downpack 7 mm (1.0 ± 1.0) (p < 0.05). The use of low-fusion cones allowed the continuous wave condensation technique to be performed at a lower depth of Downpack at 100 °C at 7 mm, with less heating in the apical third, without compromising the quality of filling. Using gutta-percha cones with low fusion, which permits a lower condensation temperature and reduced Downpack depth, maintains the quality of filling, in order to minimize possible damage to the periapical tissues.

Effect of various disinfectant solutions on the tensile strength of gutta-percha using the rapid sterilization technique.

Context: Gutta-percha (GP) gets contaminated during handling. It becomes imperative to ensure GP is sterile before placement in root canal space. Aims: The aim of the study was to evaluate and compare the tensile strength of GP treated with four different disinfectant solutions: 3% sodium hypochlorite (NaOCl), amla juice (AJ), Aloe vera (AV) juice, and pancha tulsi (PT). Settings and Design: The study design was an in vitro study. Materials and Methods: Fifty GP cones with a size of 30 were procured from sealed packages in five different groups. Experimental groups were disinfected for 1 min with 3% NaOCl, AJ, AV, and PT except the control group. Tensile and Brinell Testing Machine is used to measure the tensile strengths of GP. Statistical Analysis Used: Results were subjected to statistical analysis using the Kruskal-Wallis test followed by Dunn's post hoc test. Results: The mean tensile strength values for Groups A, B, C, D, and E are 9.49 Mpa, 13.33 Mpa, 12.58 Mpa, 12.69 MPa, and 13.56 MPa, respectively. In the herbal disinfectant group, such as AJ, AV, and PT, the tensile strength was not significantly altered, whereas in the 3% NaOCl group, it was reduced considerably. Conclusions: AJ, AV juice, and PT as a GP disinfectant do not alter the tensile strength of GP cones.

Comparing the softening effect of three gutta-percha solvents on different types of gutta-percha with different application durations.

Introduction: During non-surgical endodontic retreatment, gutta-percha (GP) solvents are indispensable in difficult cases when used with mechanical removal, however studies comparing their efficacy against different types of GP are limited. The purpose of this study was to investigate the softening effect of three solvents on the conventional (CGP), cross-linked carrier-based (CLGP), and thermoplasticized (TGP) and compare the effect of time on the softening effect of the solvents. Methods: Tested GP were embedded in cuboidal blocks of stone with their upper surfaces exposed (1 mm diameter). Three commercial GP solvents based on D-Limonene (DL), Eucalyptol oil (EO), and orange oil (OO) were added to the exposed GP before an indenter (weight = 1Kg) was applied. Using a digital camera, the indentation depth was measured (mm) directly after applying the solvent and indenter (T = 0), and after 1, 2, and 3 min of application (T = 1,2,3). The means of indentation depth were calculated and compared using a two-way analysis of variance and Tukey's post-hoc test to assess the effect of the types of solvent, GP for each application duration, and Friedman's test to evaluate the effect of application duration on the softening effect of solvents. Results: The type of GP (F = 261.43, p < 0.001), type of solvent (F = 3.57, p = 0.015), and application duration (F = 53.088, p < 0.001) were all found to significantly affect GP softening. DL exhibited the highest and only significant effect on CGP after 1 min (p < 0.05), while OO had the only significant effect against CLGP when applied for at least 2 min (p < 0.05). Both OO and EO had significant softening effects on TGP instantly or after 1 min of application, respectively. Conclusions: The results of this study revealed that the softening effect of GP solvents varies depending on their type, their application duration, and the type of GP.

Comparative analysis of novel heat-treated retreatment file system on the removal of obturating material using nano-computed tomography.

Introduction: The aim of nonsurgical retreatment is to remove the previous filling material followed by chemo-mechanical preparation of the canal to achieve proper disinfection of the root canal system. This is then followed by re-obturation. This study evaluates the time taken to retrieve the gutta-percha and the quantity of remaining filling material after retreatment with two different file systems. The quantity of remaining filling material was assessed using nano-computed tomography (CT) due to its increased accuracy. Materials and Methods: Forty extracted single-rooted teeth were split into two groups at random and decoronated and obturated at a standard root length of 16 mm. Solite RS3 (SRS-3) Retreatment and ProTaper Universal Retreatment (PTUR) systems were used to retrieve the gutta-percha after a preoperative nano-CT scan. Postoperative nano-CT scan was taken and both the scans were superimposed to quantify the remaining filling material. The time taken to remove gutta-percha was measured using a stopwatch. The statistical analysis comparing the two groups was conducted using the independent t-test. Results: The quantitative analysis of remaining filling material using nano-CT showed no statistical difference between both the file systems used (P > 0.05). However, SRS-3 took significantly less time in the removal of gutta-percha (P < 0.05). Conclusion: Hence, we can conclude that there is no significant difference in the amount of remaining filling material between both the file systems. However, time taken to remove the gutta-percha was lesser in SRS-3 compared to PTUR file system.

Efficacy of calcium hypochlorite in disinfection of gutta-percha cones contaminated with Candida albicans.

This study aimed to compare the efficacy of 2.5% sodium hypochlorite (NaOCl), 2.5% calcium hypochlorite [Ca(OCl)2], and 2% chlorhexidine (CHX) in the rapid disinfection of gutta-percha cones contaminated with Candida albicans. The minimum inhibitory and minimum fungicidal concentrations of each solution for C. albicans were determined and the ability of each solution to destroy and inhibit biofilm in culture wells was tested. In addition, ninety-eight gutta-percha cones contaminated with the fungal suspension were disinfected according to the type of solution (2.5% NaOCl, 2.5% Ca(OCl)2 or 2% CHX) in its different application methods (without agitation, ultrasonic agitation or agitation with Easy Clean), and regarding the exposure time to each irrigating solution (1 or 5 min). Next, the samples were checked for turbidity and evaluation of viable colonies. The compounds that showed the best performance in biofilm destruction were NaOCl and Ca(OCl)2 at a concentration of 2xMIC (p < 0.001). Regarding inhibited biofilm, the only compound that was effective at all MIC concentrations tested was 2.5% Ca(OCl)2 (p < 0.0001). Regarding the viable colonies, all solutions were effective concerning the control group, for all application methods, in 1 and 5 min (p < 0.05). The densitometer reading showed that CHX was the only effective solution in all application methods performed (p < 0.05). The results demonstrate that all tested solutions were effective in the rapid decontamination of cones contaminated with C. albicans.

Performance of obturation techniques in anatomical irregularities located at different thirds of the root canal system

Abstract This study aimed to compare the quality of root canal obturation (ratio of area occupied by gutta-percha (G), sealer (S), and presence of voids (V)) in different anatomical irregularities (intercanal communications, lateral irregularities, and accessory canals) located at different thirds of the root canal system of mandibular molar replicas. Sixty-seven 3D printed replicas of an accessed mandibular molar were prepared using ProGlider and ProTaper Gold rotatory systems. Three specimens were randomly selected to be used as controls and did not receive further treatment. The rest were randomly distributed in 4 experimental groups to be obturated using either cold lateral compaction (LC), continuous wave of condensation (CW), and core-carrier obturation (ThermafilPlus (TH) or GuttaCore (GC)) (n=16 per group). AHPlus® sealer was used in all groups. The three controls and a specimen from each experimental group were scanned using micro-computed tomography. The rest of the replicas were sectioned at the sites of anatomical irregularities and examined at 30× magnification. The G, S, and V ratios were calculated dividing the area occupied with each element by the total root canal area and then compared among groups using the Kruskal-Wallis test. Voids were present in all obturation techniques with ratios from 0.01 to 0.15. CW obtained a significantly higher G ratio in the irregularity located in the coronal third (0.882) than LC (0.681), TH (0.773), and GC (0.801) (p<0.05). TH and GC achieved significantly higher G ratios in those located in the apical third (p<0.05). The worst quality of obturation was observed in the loop accessory canal with all obturation techniques. Whitin the limitations of this study, it can be concluded that CW and core-carrier obturation are respectively the most effective techniques for obturating anatomical irregularities located in the coronal and the apical third.