Ultrasonic Tip Research Articles

Impact of different agitation methods on smear layer cleaning of mesial canals with accentuated curvature.

This study evaluated the impact of different methods of irrigant agitation on smear layer removal in the apical third of curved mesial canals of 3 dimensionally (D) printed mandibular molars. Sixty 3D-printed mandibular second molars were used, presenting a 70° curvature and a Vertucci type II configuration in the mesial root. A round cavity was cut 2 mm from the apex using a trephine of 2 mm in diameter, 60 bovine dentin disks were made, and a smear layer was formed. The dentin disks had the adaptation checked in the apical third of the teeth with wax. The dentin disks were evaluated in environmental scanning electron microscope before and after the following irrigant agitation methods: G1(PIK Ultrasonic Tip), G2 (Passive Ultrasonic Irrigation with Irrisonic- PUI), G3 (Easy Clean), G4 (HBW Ultrasonic Tip), G5 (Ultramint X Ultrasonic tip), and G6 (conventional irrigation-CI) (n = 10). All groups were irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. All dentin disks were 100% covered by the smear layer before treatment, and all groups significantly reduced the percentage of the smear layer after treatment. After the irrigation protocols, the Ultra-X group showed the lowest coverage percentage, statistically differing from the conventional, PIK, and HBW groups (p < 0.05). There was no significant difference among Ultramint X, PUI-Irrisonic, and Easy Clean (p > 0.05). None of the agitation methods could remove the smear layer altogether. Ultramint X resulted in the most significant number of completely clean specimens.

A Comparative Evaluation of Root Surface Roughness After Instrumentation with Gracey Curettes, Ultrasonic and Piezo-Surgery Driven Diamond Coated Tips: An In-Vitro SEM Study

Background To evaluate root surface roughness after instrumentation with Gracey curettes Ultrasonic scaler and diamond coated piezo-surgery tips using scanning electron microscope SEM.Methods Sixty-six mandibular premolar teeth indicated for extraction were collected stored mounted and analysed. These were divided randomly into three groups with 22 samples in each group. In Group A instrumentation was done with Gracey curettes Group B with ultrasonic scaler and Group C with piezosurgery driven diamond coated tips. The samples were then subjected to SEM analysis at a magnification of 1500x. The collected data was analysed using both descriptive and inferential statistics. Chi-square test t test ANOVA and other necessary statistical tests were used. P lt0.05 was considered to be significant. The analysis of the data was carried out using SPSS version 20 software.Results Multiple comparisons of mean surface roughness scores showed no significant difference between Gracey curette and Ultrasonic scaler tip P0.063. No statistical significant difference was found between Gracey curette and Piezo surgical unit P0.984. However there was a statistically significant difference between Ultrasonic scaler tip and Piezo surgical unit P lt0.004. It can be inferred from the results that the surface roughness is different in both Ultrasonic scaler tip and Piezo surgical unit groups.Conclusion The use of diamond-coated tips tends to produce more surface roughness than routinely used ultrasonic scaler tips and manual instrumentation.

Comparing the Efficiency of Single versus Dual Ultrasonic Devices for Metallic Post Removal in Endodontic Retreatment: A Clinical Study.

Ultrasonic vibration for metallic post removal seems to be a unanimous choice between endodontists and general practitioners for providing the best results and having the highest safety. This study compared the time required by ultrasonic vibration for removing metallic post (MP) when 1 or 2 ultrasonics devices are used. One hundred and fifteen teeth with MPs from 105 patients, indicated for nonsurgical endodontic retreatment were divided into 2 groups according to the number of ultrasonic devices used (G1-1 device) and (G2-2 devices). In G1, the MP was worn with a transmetal bur, alongside the wear of the cement line (around 2 mm deep). Then, an ultrasonic tip attached to an ultrasonic unit, with a power of 100% was activated at the level of the post, with constant water spray at a level of 1 mm above the axial surface of the tooth. The position of the tip was changed between buccal and lingual surfaces every 10 seconds until the MP was removed. In G2 the same procedures were performed as described in G1, but two ultrasonic tips were activated simultaneously at buccal and lingual surfaces until the MP was removed. The vibration time necessary for removing each MP was recorded using a chronometer. The mean time was 131.10±29.68 seconds (mean±standard error of the mean) for MP removal using one ultrasonic device, and 24.86±6.88 seconds for two devices. The time required for MP removal using two ultrasonic devices was significantly less than when using one ultrasonic device (P<0.001). The technique with 2 ultrasonic devices proved to be more efficient than the one using only 1 ultrasonic device.

Filling ability of ready-to-use or powder-liquid calcium silicate-based sealers after ultrasonic agitation.

This study evaluated the effect of ultrasonic agitation on the filling capacity of ready-to-use calcium silicate-based sealer Bio-C Sealer (BCS, Angelus, Paraná, Brazil) or powder-liquid BioRoot RCS (BR, Septodont, Saint-Maur-des-Fossés, France) using curved artificial canals by micro-computed tomography (micro-CT). Additionally, flow (mm) and flow area (mm2) were evaluated for both materials. Acrylic resin main canal (60° curvature and 5 mm radius, with 3 lateral canals in the cervical, middle, and apical thirds) were prepared up to size 40/.05 (Prodesign Logic, Brazil). The agitation method was used with ultrasonic tip (US, Irrisonic, Helse, Brazil): BCS, BCS/US, BR, and BR/US. All specimens were filled using the single-cone technique. The samples were scanned by micro-CT (8,74 µm) after obturation. The percentage of filling material and voids were calculated. Flow was evaluated based on ISO 6876/2012 standards (mm) and area (mm2). The data were statistically analyzed using ANOVA and Tukey tests (α = 0.05). BR/US showed lower percentage of filling material in the lateral canals than and, BCS/US (p<0.05). BR/US resulted in a higher percentage of voids than BR in the lateral apical third (p<0.05). BCS showed higher flow than BR (p<0.05). BCS and BR presented proper filling capacity in the simulated curved canals regardless of the use of ultrasonic agitation. However, BR/US showed more voids in the apical third. BCS demonstrates higher filling ability.

Ultrasonically induced nanofatigue monitoring during nanoindentation

The ultrasonic nanoindentation tip integrated into a nanoindenter operates at hundreds of kHz, inducing millions of load cycles within seconds at the localized mechanical contact point. Then operating on brittle submicron thick films such as SiC, the resulting accumulated nanofatigue exhibits different contact fracture modes. During the process of quasi-static loading with ultrasonic excitation, the ultrasonic nanoindentation tip monitors associated acoustic waveforms, which can provide additional insights into the nanofatigue process dynamics via advanced acoustic waveform analysis and deep learning classifications.

The Effect of Combined Ultrasonic Tip and Mechanized Instrumentation on the Reduction of the Percentage of Non-Instrumented Surfaces in Oval/Flat Root Canals: A Systematic Review and Meta-Analysis.

This systematic review and meta-analysis aimed to evaluate the effectiveness of the ultrasonic tip associated with mechanized instrumentation in reducing the percentage of non-instrumented surfaces of human teeth with oval or flattened root canals. The study followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Pubmed/MEDLINE (Medical Literature Analysis and Retrieval System Online), Scopus, Embase, Web of Science, and Cochrane Library were searched for literature published till October 2022. Only in vitrostudies were included, which compared conventional mechanized endodontic treatment alone against conventional endodontic treatment in association with ultrasonic tips, evaluating the reduction in the percentage of non-instrumented walls (computed microtomography). Four studies were eligible for qualitative and quantitative analysis. The majority of the studies scored low for risk of bias. The meta-analysis comparing protocols demonstrated a reduced percentage of non-instrumented walls in groups using ultrasonic tips after the conventional mechanized technique (p<0.01) with a confidence interval of 1.04 (95%CI: 0.59, 1.50). The ultrasonic tip associated with mechanized instrumentation demonstrates a significant reduction in the percentage of non-instrumented surfaces in oval or flattened canals.

Periapical Pathologies Treated with Conservative Approach

Periapical pathologies are encountered routinely on an endodontically compromised tooth which may or may not be painful. The lesions resulting from few millimeters to centimeters can be a cyst, granuloma or an abscess combinedly comprising up to more than 90% of all periapical lesions. Various methods can be used for the treatment of the periapical lesions using modern endodontic techniques including endodontic microscopes, ultrasonic irrigation tips, intra canal calcium hydroxide medicaments, advanced cleaning and shaping endodontic files and advanced obturation techniques. The goal of the endodontic treatment is to provide a complete aseptic environment with complete sealing of root canal and coronal restoration with absolute eradication of any microbial growth for successful resolution of the lesions. We are reporting here multiple cases where we used calcium hydroxide as an intra-canal medicament for its antibacterial properties and intra-canal medicament for the treatment of periapical lesions.

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

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

Endodontic Ultrasonic Tips: A Review

This review highlights the endodontic ultrasonic tips. Ultrasounds (US) were discovered within the 18th century thanks to their employment within the kingdom Animalia. Richman was the primary to supply this approach to endodontics in 1957. Endodontics now uses ultrasound to irrigate root canals, remove posts, damaged tools, and other obstacles from the foundation canal, distribute sealant across the root canal walls, condense gutta-percha root fillings, and improve dentin permeability during bleaching. Ultrasonics have progressed from primary instrumentation to a passive ultrasonic cleaning approach in root canals. Modern ultrasonic units must be capable of high power and precision cutting, further because of the ability to manage not only the frequency but also the amplitude of the vibrations. Ultrasonic tip designs range from basic curves to multiangled bends and are available in varying form of shapes and sizes. Over the previous 65 years, the evolution of ultrasound in dentistry has been examined.

A laboratory pilot study on voids in flowable bulk-fill composite restorations in bovine Class-II and endodontic access cavities after sonic vibration

This pilot study investigated whether sonic-powered application of a bulk-fill resin-based composite (RBC) in Class-II or endodontic access cavities reduces void formation. The crowns and roots of 60 bovine teeth with Class-II cavities (C) and endodontic access cavities (E) respectively, were assigned to ten groups (C1–C5, E1–E5). Cavities were filled with RBC (SDR flow + , one increment) using different application techniques: no adaptation (C1 + E1), spreading of RBC on the cavity surfaces with a dental explorer tip (C2 + E2), low (C3 + E3) or high frequency (C4 + E4) direct activation by inserting a sonic-powered tip into RBC and high frequency indirect activation with an ultrasonic insertion tip (C5 + E5). The restorations were light-cured and investigated for voids using microtomography. The number of voids and percentage of voids related to the volume were statistically analysed (α < 0.05). While most voids in Class-II restorations were observed in C4 (p ≤ 0.0031), no significant differences were found between the other groups (p > 0.05). The percentage of voids showed no differences in E1-E5 (p > 0.05). C4 showed a significantly higher percentage of voids compared to C2 (p < 0.001). There is no benefit in applying sonic vibration when filling Class-II or endodontic access cavities.

Effect of Endo-Z bur or Bladesonic ultrasonic tip on the adaptation of filling material. A micro-CT study.

This study aimed to evaluate the effect of apicoectomy performed with a bur or an ultrasonic tip on the adaptation of the filling material to root canal dentin. Twenty human mandibular incisors were selected and prepared with a ProDesign Logic system up to diameter 40/.05. The root canals were filled with Bio-C Sealer (Angelus, PR, Brazil) using the single cone technique and were stored at 37ºC and 95% relative humidity for 7 days. After this period, the apicoectomy of the 3 millimeters of the root apex was performed using Endo-Z bur (Dentsply Sirona) or Bladesonic ultrasonic tip (Helse Ultrasonic, Santa Rosa de Viterbo, Brazil) (n=10). The specimens were scanned by micro-computed tomography (micro-CT; SkyScan 1176) with a voxel size of 8.74 µm after obturation and after apicoectomy. The percentage of voids at the interface between the filling material and the root canal wall was evaluated in the apical 4 mm of the root after apicoectomy, besides the time cutting to both devices. The data obtained were submitted to paired and unpaired t-tests (α = 0.05). Endo-Z and Bladesonic increased the percentage of voids between the filling material and the dentin after apicectomy (p<0.05), and they were similar (p>0.05). Endo-Z has a shorter time to perform apicoectomy compared to Bladesonic (p<0.05). Apicectomies with Endo-Z or Bladesonic could harm the material/dentin interface, while the Endo-Z bur was faster than the Bladesonic ultrasonic tip.

Comparison of root end sealing ability of three retrograde filling materials in teeth with root apices resected at 900 using dye penetration method under fluorescent microscope

Background: The main factor contributing to surgical endodontic dissatisfaction is an inadequate seal at the apex. The material used for retrograde filling should prevent contaminants from penetrating periradicular tissue. So the objective of this study was to evaluate and compare the ability of Mineral Trioxide Aggregate (MTA), Zirconomer and bioactive bone cement to seal the root end as retrograde filling material with apices resected at 900 angles using dye penetration method under fluorescent microscope. Methods: 36 extracted teeth samples were cut at Cementoenamel junction horizontally. Following the customary protocols of, cleaning, shaping and obturation with gutta percha and AH Plus sealer, resection of samples was done 3mm at the apical end at 90 degree angle along the long axis of the tooth with the help of diamond disc. A depth of 3mm of root end cavity was made with diamond coated ultrasonic surgical tip. The samples were randomly allocated in 3 groups: Group I: MTA ; Group II : Zirconomer; Group III: Bioactive Bone Cement . Coating of nail varnish was done with the roots except at the tip. Each material was compacted in the retrocavity using small pluggers. All the retrofilled samples were kept in acridine orange for 24 hours, following which cleaning &amp; bucco-lingual sectioning (vertical) was carried out. Confocal laser scanning fluorescent microscope was used for checking the dye penetration in these samples thereby evaluating sealing ability. Results: Group III (Bioactive Bone Cement) had the highest root end sealing ability with mean (1.4 ± 0.51) followed by Group I (MTA) (2.3 ± 0.65) and lastly Group II (Zirconomer) (4.1 ± 0.57) as root end filling material with apices resected at 900 angle using dye penetration method under fluorescent microscopy which were statistically significant. Conclusions: Bioactive Bone cement can be recommended as an acceptable retrograde filling material.

The Effectiveness of a Novel Air-Barrier Device for Aerosol Reduction in a Dental Environment: Computational Fluid Dynamics Simulation.

The use of equipment such as dental handpieces and ultrasonic tips in the dental environment has potentially heightened the generation and spread of aerosols, which are dispersant particles contaminated by etiological factors. Although numerous types of personal protective equipment have been used to lower contact with contaminants, they generally do not exhibit excellent removal rates and user-friendliness in tandem. To solve this problem, we developed a prototype of an air-barrier device that forms an air curtain as well as performs suction and evaluated the effect of this newly developed device through a simulation study and experiments. The air-barrier device derived the improved design for reducing bioaerosols through the simulation results. The experiments also demonstrated that air-barrier devices are effective in reducing bioaerosols generated at a distance in a dental environment. In conclusion, this study demonstrates that air-barrier devices in dental environments can play an effective role in reducing contaminating particles.

Assessment of the root surface temperature during the use of intracanal agitation systems: In vitro study.

This study aimed to evaluate the temperature changes that the different methods of agitation of irrigants promote on the external dental root surface. Nine extracted human lower premolars were standardized by cone-beam computed tomography and used. The root canal was instrumented with a Reciproc 40.06 file. Temperature measurement was performed using K-type thermocouple sensors attached to the middle, cervical, and apical thirds of the teeth. The teeth had their roots immersed in distilled water at 37ºC, which were distributed into 3 experimental groups according to the mechanical agitation methods to be studied. US Group (n=3), Irrisonic Ultrasonic Tip activated through ultrasound; EC Group (n=3), Easyclean Tip coupled to a contra-angle low-speed handpiece; XP Group (n=3), XP-endo Finisher file coupled to an endodontic electrical motor. Temperature measurements were performed simultaneously with agitation and irrigation of intracanal irrigants. Statistical analysis was performed using SPSS software with a significance level of 5%. For multiple comparisons, the Tukey test was used. The association between mechanical agitation methods and root third was statistically significant. Regarding the temperatures recorded on the external surface of the roots, the ultrasonic tip was significantly higher than the XP-endo Finisher file and the Easyclean tip, which did not differ from each other. Regarding the ultrasonic tip, the external temperature in the middle third (39.46ºC) of the root was significantly lower than in the cervical (40.41ºC) and apical third (40.53ºC). None of the agitation methods of irrigants studied presented heating above 47ºC, and their use is safe for periodontal tissues.

THE INFLUENCE OF ULTRASONIC ACTIVATION ON THE SETTING TIME AND FLOW OF FOUR ENDODONTIC SEALERS

The aim of the present study was to evaluate the influence of ultrasonic activation (UA) on the setting time and flow of four endodontic sealers: AH Plus (AH), Sealer Plus (SP), MTA Fillapex (MTAF), and BioRoot RCS (BIO). Properties were evaluated as required by ANSI/ADA Specification N° 57 (2008); only the size of the specimens was modified. UA was applied using a smooth tapered ultrasonic tip coupled to a piezoelectric ultrasonic device (30% power) on the freshly mixed materials in two cycles of 20 seconds. The results were statistically analyzed using the ANOVA and Kruskal-Wallis tests, followed by the Tukey and Dunn posthoc tests, respectively, depending on the normality of the data. The shortest setting times, initial and final, were, 115 (BIO/UA) and 148.6 (BIO/UA) min, whereas the longest were 1215 (AH) and 1928 (AH) min. The MTAF sealer did not set throughout the experimental period (2880 minutes). Significant differences were observed between BIO and MTAF and the other sealers, with or without UA, both in the initial and final setting time (P &lt; 0.05). UA did not change the initial setting times; however, it reduced the final setting of BIO (P &lt; 0.05). The highest and lowest flow values observed were 25.52 mm (AH/UA) and 18.66 mm (BIO/UA), respectively. The AH sealer, regardless of UA, exhibited higher flow values compared to the other sealers (P &lt; 0.05), except for the MTAF/UA group, which was the only sealer in which UA promoted a significant flow increase (P &lt; 0.05). Under the conditions of the study, it can be concluded that the BIO, under UA, presented the lowest setting time; however, it exhibited the lowest flow values. The MTAF sealer did not reach its final setting. Moreover, the SP groups exhibited intermediate results in all analyses. In summary, only the final setting time of the BIO group and the flow values of the MTAF group were influenced by UA.

Endodontic Clinical Outcome after Separated Instrument Removal Using a Spinal Needle Technique: A Retrospective Study of Thirty Years of Clinical Experience

IntroductionCurrent methods for the removal of separated endodontic instruments (RSI) are not predictable. MethodsThe primary outcome of this retrospective study was to assess the clinical and radiographic success (CRS) of teeth in case of RSI after a 5-year follow-up. Secondary outcomes were to evaluate (1) the effectiveness in RSI and (2) the risk of root fracture after RSI. The study protocol was registered at ClinicalTrials.gov (ID: NCT05128266). The patients were treated by the same endodontist between January 1991 and December 2019. The RSI was performed under the operative microscope as follows: first, the dentine surrounding the coronal part of the broken instrument was selectively removed by using a small ultrasonic tip to loosen the fragment; then, a modified spinal needle was used to catch and remove the instrument. The 1-, 3-, 5-, and >5-year CRS were recorded. Logistic regression analysis was performed to determine independent predictors of failure (ie, tooth number, type of root canal, shape of the root canal, type of broken instrument, apicocoronal level of the separated instrument, presence of periapical lesions, and root perforations). ResultsA total of 158 teeth were included in this study. Finally, 131 instruments underwent RSI (82.9%). RSI was an independent predictor of CRS after 1-year of treatment (odds ratio: 58.3; 95% confidence interval: 27.42–95.73, P < .05). At the 5-year follow-up, only 10 of 131 teeth (7.6%) failed. All failures were caused by root fracture (10/10) (χ2 test, P < .05). Separated instruments located in the apical third of the root were more difficult to remove (13/49 cases, 26.5%; χ2 test, P < .05). ConclusionsThe proposed technique can achieve excellent effectiveness in RSI, can achieve a high CRS rate when a periapical lesion is present, is not associated to a significant increase in root fracture incidence, and should be performed with the help of an operative microscope.

Intraradicular Dentinal Changes Following Fiber Postremoval: Micro-computed Tomography Analysis

Abstract Context: Excessive dentine wear during postremoval can occur due to the adhesion between the cement and the post. Aim: The aim is to evaluate dentine wear and microcrack occurrence following the removal of intraradicular fiberglass posts that were previously cemented with two types of resin cement. Methods: Distal roots (n = 38) of lower molars were instrumented, filled, prepared for intraradicular postinstallation, and divided into two groups according to the cement used for the posts: RelyX ARC or RelyX U200. The posts were removed through abrasion using ultrasonic diamond tips, after which the degrees of dentine wear (volume/mm3) and microcrack formation were assessed using microcomputed tomographic imaging. Statistical Analysis Used: The Mann–Whitney U (P ≤ 0.05) and Chi-squared tests (P ≤ 0.05) were used. Results: After the removal of the posts, no statistically significant difference in root canal volume or microcrack occurrence was observed between the groups (P &gt; 0.05). The procedure produced significant dentine wear regardless of the type of cement used (P &lt; 0.05). Conclusions: The removal of fiberglass posts caused extensive dentine wear but did not influence microcrack occurrence. The type of resin cement used did not affect the dentine loss or microcrack appearance that resulted from fiberglass postremoval.

Effect of Various Acid Solutions as an Aid in Removing the OrthoMTA-Based Root Canal Filling

The objectives of this study were to compare the effects of various acid solutions combined with ultrasonics as an aid to remove mineral trioxide aggregate (MTA)-based root canal filling and to assess their effect on the surface topography and microhardness of root canal dentin. Materials and Method: Fifty human permanent single rooted and single canaled freshly extracted teeth were decoronated and sectioned apically to prepare the middle third of root sections of 5 mm length. The canals were prepared in a step-back manner. OrthoMTA was packed throughout the prepared canals. These root sections were incubated for one week and subsequently randomly allocated to five groups (n = 10) according to the OrthoMTA removal method: No treatment (NT); 5% glycolic acid + ultrasonics (5% GA+U); 10% glycolic acid + ultrasonics (10% GA+U); 10% citric acid + ultrasonics (10% CA+U); Distilled water + ultrasonics (DW+U). A 1 mm deep well was created within the coronal end of the set OrthoMTA. Wells were filled with each respective test solution and left for 5 min. Thereafter, further removal of OrthoMTA used a specific ultrasonic tip. Finally, the canals were flushed using 1 mL of the respective test solutions and activated with a Controlled Memory ultrasonic tip for two cycles of 20 s each followed by flushing with 1 mL of distilled water and paper point drying of the canals. Then, specimens were longitudinally split into two halves and examined under a scanning electron microscope (1000×) to assess the residual OrthoMTA and surface topography of root canal dentin. The Vickers surface microhardness of treated radicular dentin was measured using the HMV-2 microhardness tester. Result: Data were analysed using one-way ANOVA followed by Tukey’s post hoc test. Significant differences for residual OrthoMTA were observed between (10% GA+U) with (5% GA+U), (10% CA+U), (DW+U) and (NT) (p value &lt; 0.01). In the context of microhardness, (5% GA+U) and (10% GA+U) showed statistically significant difference compared to (NT), (10% CA+U) and (DW+U) (p value &lt; 0.01). Conclusion: 10% GA+U was superior to other tested groups in removing OrthoMTA, but it substantially reduced dentin microhardness.

Comparison of the Microleakages of Four Root-End Filling Materials: An In Vitro Study.

When a nonsurgical endodontic treatment is ineffective, surgery is necessary. This entails putting a retrofilling to seal the tooth's apex. Exposing the lesion, performing a curettage, exposing the root apex, resecting it, preparing the root end, and lastly filling the cavity with the proper material are all steps in endodontic surgery. Thus, the aim of this study is to compare the apical microleakage of four root-end filling materials in cavities prepared using ultrasonic retro tip in in vitro conditions. An in vitrostudy was conducted on 60 extracted single-rooted teeth and was cut at the cementoenamel junction (CEJ). They were biomechanically prepared and obturated. Apical 3 mm root-end resection was done using a diamond disc. Root-end cavities were made using an ultrasonic retro tip. Teeth were separated into four groups and filled with SuperEBA®️ ethoxy-benzoic acid (EBA; Keystone Industries, New Jersey), mineral trioxide aggregate (MTA), Biodentine (Septodont, France), and TotalFill Bioceramic Root Repair Material (BC RRM; FKG Dentaire Sàrl, Switzerland). The samples were kept in methylene blue dye and split longitudinally. The degree of dye penetration was observed under a stereomicroscope and scored. Finally, the results were analyzed. TotalFill BC RRM and Biodentine showed the least apical microleakage (p <0.05).Group 1 samples had the highest mean microleakage, followed by Group 2, Group 3, and Group 4 samples. All of the sample groups showed some evidence of microleakage, but not all of the samples showed leaking. SuperEBA (Group 1) demonstrated the highest microleakage when compared to the other groups.

Experimental study on the reliability of thermal analysis techniques in the in-situ combustion of heavy oil

ABSTRACT In situ combustion (ISC) is an effective method to enhance heavy oil (HO) recovery. Thermal analysis (TA) techniques are considered ideal tools for study the HO oxidation. However, the reliability of TA data has been affected by the strong adhesion of high viscosity HO to the substrate and crucible. Consequently, there has been a deviation in the DTA peak temperature for both low and high-temperature oxidation of HO and HO/clay mixtures at 7°C, 19°C, and 8°C, 11°C respectively. Additionally, negative values of reaction activation energy (E α ) were observed, reaching up to −1395.94 ± 836.2 kJ mol−1. This study aimed to identify factors that impact TA data reliability and oxidation kinetics. By implementing solutions such as ultrasonic stirring and needle tip loading, this study was able to improve the accuracy and reproducibility of TA data and E α value. The results of this investigation provide valuable insight for future ISC.