Condensation Technique Research Articles

Photophysical and Physiochemical Study of New Pyrenyl Chalcone Derivatives as Sensitizers for Organic Solar Cells

Three pyrenyl chalcone derivatives namely, PCH1, PCH2, and PCH3 were synthesized by utilizing the Claisen-Schmidt condensation technique. Compound PCH1 was successfully recrystallized via the slow evaporation technique. To determine and refine the crystal structure, the single crystal is subjected to X-ray diffraction (XRD) analysis. Crystal packing reveals that intermolecular C-H···O interactions bind molecules in compound PCH1 in a head-to-head arrangement. Intramolecular charge transfer (ICT) between molecules has improved as a result of the compound’s C-H···O contacts. The compounds were then characterized using UV-Vis spectroscopy where all compounds have an energy gap that is within the low range, ranging from 2.89 to 2.94 nm. Furthermore, the HOMO-LUMO energy levels of the pyrenyl chalcones were examined by conducting CV analysis. The energy levels of the compounds essentially lie between the conduction band of TiO2 and the redox potential ( I − / I 3 − ) of the electrolyte. FESEM and EDX analyses were utilized in solar cell performance investigations to examine the surface topography and elemental mapping of the pyrenyl compound on the TiO2 layer, correspondingly. Compound PCH2 emerges as the most effective dye-sensitizer in DSSC applications due to the anchoring of strong substituent groups in the compound, even though all three compounds demonstrated suitability as dye-sensitizer materials.

Damage Identification of Full-Scale Steel Truss Structure Based on Model Condensation and Mean-Value Normalization Regularization Techniques

Structural health monitoring and damage identification aim to detect the internal damage and evaluate the health conditions of the practical engineering structure, which has been the most popular research field for several decades. The sensitivity-based method incorporated with the regularization techniques is the classical and useful approach, and it can obtain accurate damage detection results. However, with the development of civil engineering structures, this classical method faces two problems: one is it is only applied to simple structures rather than full-scale structures, and second is the iterative calculation efficiency is lower. Therefore, aiming at these drawbacks, the two improvement strategies have been introduced to the original method for its enhancement in the application potential and computational efficiency. The proposed method has been verified based on two examples, i.e., a numerical steel truss with 144 elements and a full-scale experimental steel truss with 160 elements. The results prove that the proposed method has better efficiency and good application potential in the practical full-scale engineering structure.

Three-Dimensional Measurement of Obturation Quality of Bioceramic Materials in Filling Artificial Internal Root Resorption Cavities Using Different Obturation Techniques: An In Vitro Comparative Study

IntroductionPathologic conditions such as internal root resorption (IRR) may complicate root canal filling. This study aimed to evaluate and compare the obturation quality by measuring the percentage of obturation volume (POV) in root canals with artificial IRR obturated with different materials and techniques using cone beam computed tomography (CBCT). MethodsForty single canal extracted mandibular premolars were decoronated to standardize their length to 14 mm. Following instrumentation, the roots were cut horizontally, and artificial IRR cavities were made at the level of 7 mm from the apex. The root halves were joined using cyanoacrylate adhesive. The samples were randomly assigned to 4 groups (n = 10), and the canals were filled as follows: single-cone technique (SC), bulk-fill Bio-C Sealer (BF), and Bio-C Repair for the coronal and middle third (BCR) + cold lateral condensation technique (CLC) for the apical third and continuous wave compaction technique (CWC). The pre- and postobturation volumes and the POV were measured in the total canal and for the apical, middle, and coronal thirds separately using CBCT and Mimics Medical software. The results were analyzed statistically using one-way ANOVA and Tukey HSD test, and statistical significance was set at P < .05. ResultsBF group resulted in significantly lower total, coronal, middle and apical POV values compared to SC, BCR + CLC, and CWC groups (P < .05), respectively. Also, at the apical third, the BCR + CLC group showed significantly lower POV than the SC and CWC groups (P < .05), respectively. The intra-group comparison showed that BF and BCR + CLC groups had a significantly lower POV in the apical third compared to the middle third (P < .05). Conversely, the CWC group had a significantly higher apical POV than the middle third (P < .05). ConclusionsThe maximum POV was obtained using the CWC technique, Bio-C Repair, and SC technique with Bio-C Sealer, making their application in IRR more preferable than the BF Bio-C Sealer.

Konsep Daur Belajar sebagai Implementasi Manajemen Kurikulum di Sanggar Anak Alam Yogyakarta

This research aims to describe the learning cycle concept as an implementation of curriculum management at Sanggar Anak Alam (SALAM) Yogyakarta. Indonesia's curriculum policy nomenclature changes from year to year, however, Sanggar Anak Alam (SALAM) itself consistently carries out learning cycle-based curriculum practices as a form of research. This curriculum practice has been running since the inception of SALAM in 1988 until now. Researchers use a case study approach with a qualitative type of research. Data was obtained through interviews, observation and documentation. The data is then analyzed using condensation techniques, presenting the data until conclusions are drawn. The results of the research include first, SALAM holistic education is carried out through a learning cycle and is supported by activities such as the Monday Legi market and minitrip. Second, learning cycle-based curriculum management practices with curriculum planning, implementation and evaluation. Curriculum management through the learning cycle positions students as real subjects, choosing to carry out and achieve goals with the help of facilitators so that holistic education is achieved.

Management of Separated Endodontic Instrument in Mandibular Second Molar with Bypass Technique

One of the most common mishaps in root canal treatment is a separated endodontic instrument. Bypass technique is an effective alternative besides file retrieval while clinical conditions have lack of access and visibility. Other than, this technique gives a more conservative outcome because it prevents more dentin removal. The aim of this case report was to describe management of separated endodontic instruments in the mandibular second molar with bypass technique during endodontic treatment. A 3,5 mm F1 ProTaper Hand Use file was separated in the mesiobuccal canal of the mandibular second molar. Radiograph examination was taken to make sure the level of fragment. Bypass was performed with #10 until #25 K-File to pass the separated instrument through the gap between it and the root canal wall. Obturation has been done with gutta percha and resin-based sealer using cold lateral condensation technique. Direct restoration was chosen as final restoration after 6 days follow up. Bypass technique can be performed as management of separated instrument considering the risks involved fragment extrusion to apical region, secondary separated instrument, and conservative aspect.

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 4mm from the WL; II-low-fusion cone with Downpack at 100°C up to 4mm from the WL; III-low-fusion cone with Downpack at 100°C up to 7mm 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 7mm Downpack showed higher bond strength (4.2 ± 2.7) compared with conventional cones (2.8 ± 1.6) and low-fusion cones with 4mm 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 7mm (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 7mm, 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.

Complicating the debate: Evaluating the potential of gas-chromatography-mass spectrometry for differentiating prehistoric aceramic tar production techniques

Birch bark tar was used extensively throughout human history. While later ceramic-based production technologies are known, prehistoric aceramic techniques leave little to no archaeological evidence. Experimental tar production attempts to fill this gap and suggest potential techniques. However, their archaeological relevance is unclear. Through an in-depth biomolecular analysis using Gas Chromatography-Mass Spectrometry, this study attempts to differentiate tars produced using four experimental aceramic techniques: condensation, ash mound, pit roll, and raised structure. In doing so we publish the largest collection of GC-MS results of aceramic birch tars. The results show that pentacyclic triterpenoids, characteristic of birch bark, vary between the production techniques in relation to heating exposure and perhaps the tar collection method. This allows for a tentative identification of tars produced through the condensation and ash mound techniques, which were formed consistently using short periods of heating and collected systematically by scraping. In contrast, tars produced using the pit roll and raised structure techniques do not have consistent molecular signatures. Despite the partial success of Gas Chromatography-Mass Spectrometry, the archaeological relevance is questioned because this technique is only applicable to samples from optimum lipid preservation conditions when a high number of pentacyclic triterpenoids are preserved. Therefore, using Gas Chromatography-Mass Spectrometry to determine the transformation methods of organics, like birch bark, may not be an appropriate standalone technique to fairly discuss the technological capabilities of past populations.

ProTaper universal retreatment retreatment potential in oval-shaped canals filled with different obturation techniques-A micro-computed tomography study.

The objective of this in vitro micro-computed tomography investigation is to assess the efficacy of the ProTaper Universal Retreatment System in retreating oval-shaped root canals filled with three obturation procedures. Thirty-six lower incisors with a single oval root canal were prepared using XP-Endo Shaper up to size 30/0.04, and allocated into three equal groups based on the filling technique: Group 1: Warm vertical condensation technique; Group 2: GuttaCore obturators; Group 3: Cold lateral condensation technique. All samples were further retreated using the ProTaper Universal Retreatment system. Micro-CT analysis was performed before and after the retreatment procedure. Statistical analysis was performed with a significance level of 0.05. Data analysis was conducted using the Kolmogorov-Smirnov and Kruskal-Wallis H tests. The best performance of the files was achieved when the removal of the filling in the entire canal was considered. However, this outcome was not statistically significant when compared with the other observed root canal levels. The retreatment procedure could not ensure thorough cleanliness of the canal walls from filling remnants, regardless of the obturation technique and observational level. The ProTaper Universal Retreatment system used for the removal of gutta-percha and sealer in oval-shaped root canals demonstrated equal effectiveness, regardless of the obturation technique used.

Postoperative pain of minimally invasive root canal treatment:a randomized clinical trial.

This randomized clinical trial compared postoperative pain between a minimally invasive (MP) and conventional root canal treatment protocol (CP). A total of 170 mature permanent teeth (either with vital or necrotic pulp), were randomly assigned into two groups. In the CP group, ProTaper Gold (Dentsply Sirona, Ballaigues, Switzerland) and a continuous wave of condensation technique were used, whereas, in the MP group, TruNatomy (Dentsply Sirona), ultrasonic-assisted irrigation (UI), calcium hydroxide, and a sealer-based obturation technique were used. Patients recorded preoperative and postoperative pain using a 0-10 numerical rating scale (NRS) at 4h, 1, 2, 3, 4, 5, 6, and 7days after instrumentation and 1day after canal obturation, respectively. There were no significant differences in pain intensity at any time points assessed between the two groups (p > 0.05). The occurrence of moderate/intense pain after instrumentation was significantly associated with preoperative periapical index (PAI) (p = 0.017) and NRS scores (p < 0.001). Preoperative pulp status (p = 0.009) and NRS score (p = 0.006) were identified as significant factors in the occurrence of moderate/intense pain after obturation. Instrumentation unequivocally reduced pain severity for both groups. The post-endodontic pain associated with the use of MP, combined with UI, Ca(OH)2, and calcium-silicate cement, did not differ from that of CP. Preoperative pain score, PAI, and preoperative pulp status were determined to be prognostic factors for postoperative pain.

Retreatment Strategies for Cases Containing Calcium Silicate-Based Root Canal Sealers: A Comprehensive Review.

This review explores the field of retreatment strategies for cases filled with calcium silicate-based root canal sealers. Since the introduction of calcium silicate-based materials in dentistry, calcium silicate-based root canal sealers have become popular among dentists because of their biocompatibility, bioactivity, and sealing ability. Therefore, effective retreatment strategies are indispensable. This article aims to identify the challenges associated with the removal of calcium silicate-based sealers themselves and removal of gutta-percha with the sealers during retreatment, evaluate current techniques and materials, and provide future directions for research in this field. Regarding the strategies of removal of root canal sealers, calcium silicate-based sealers are still relatively new materials for clinicians compared with traditional sealers such as epoxy- or eugenol-based sealers. First, no clinically established solvents have been reported. Second, calcium silicate-based sealers are currently utilized by clinicians in either the cold sealer-based technique or the warm vertical condensation technique. Third, the setting process of calcium silicate-based sealers generates byproducts, primarily calcium hydroxide and secondarily hydroxyapatite, that could interact with dentine. Lastly, there is a lack of clinical studies evaluating the efficacy of retreatment protocols for teeth filled with calcium silicate-based sealers. Therefore, it is important to investigate the chemo-mechanical properties of calcium silicate-based sealers themselves and their reactions to solvents and/or mechanical instruments and identify the interfacial properties of calcium silicate-based sealers with respect to dentine and gutta-percha. In addition, researchers in the clinical field need to actively gather and report data on retreatments of teeth filled with calcium silicate-based sealers.

Comparative Evaluation of Push-out Bond Strength of Three Different Root Canal Sealers: An In Vitro Study.

The aim of this present study was to compare the dislodgement resistance of calcium silicate-based sealer, zinc oxide sealer, and a new sealer combining both zinc oxide and calcium silicate-based sealer in vitro. 60 single-rooted human teeth were instrumented with F3 Protaper Gold. All endodontic canals were filled using gutta percha cones using the cold lateral condensation technique in combination using one of the mentioned sealers (n = 20 per group). The teeth were divided into three groups: group A consisted of Sealite® Ultra, group B consisted of K-Sealer®, and group C consisted of BioRoot® RC. After 2 months of incubation (37°C, 100% humidity) and after cutting out 2 mm from the most apical portion of the root apex, six slices of 1 mm thickness were generated. Mechanical dislodgement resistance was examined using a universal pressure-testing machine and the push-out bond strength (POBS) was calculated. Specimens were examined under 20× magnification to define the bond failure mode. Statistical analysis was executed using ANOVA, post hoc Turkey test for pairwise comparisons and Kruskal-Wallis tests. The POBS of BioRoot® was significantly higher than the POBS of the two other sealers with a mean of 10.54 MPa ± 2.10 and 5.73 MPa ± 2.34, respectively (p < 0.001). Sealite® and K-Sealer® showed similar results in the median and coronal part. K-Sealer® revealed highest POBS compared with Sealite® in the apical part (p < 0.05). The POBS of the zinc oxide and calcium silicate-based sealer was significantly lower compared with calcium silicate. Sealite® and K-Sealer® exhibited almost same results. BioRoot showed the highest POBS of all sealers. The current study was needed to evaluate the bond strength of three different cements to dentinal walls, by evaluating their respective POBS in vitro. The findings of this study may provide guidance for the clinician in the selection of an adequate endodontic sealer that guarantees an enhanced adhesive seal between the Gutta-percha and the dentinal canal walls. How to cite this article: Makhlouf MP, El Helou JD, Zogheib CE, et al. Comparative Evaluation of Push-out Bond Strength of Three Different Root Canal Sealers: An In Vitro Study. J Contemp Dent Pract 2024;25(1):15-19.

IMPLIKASI PEMBELAJARAN BERBASIS PROYEK DALAM MENINGKATKAN PRESTASI BELAJAR SISWA: STUDI KASUS DI MADRASAH IBTIDAIYAH AL ISLAH TIUDAN KABUPATEN TULUNGAGUNG

The educational system in Indonesia prioritizes learning methodologies that foster active student engagement, supported by the adoption of the Merdeka Belajar Curriculum across all educational levels. Among these methodologies, project-based learning stands out. This study aims to investigate the implications of implementing project-based learning in the subject of Qur'an Hadith, with the goal of improving student learning outcomes at Madrasah Ibtidaiyah Al Islah Tiudan, Tulungagung Regency. Conducted from April to August 2023, the research employed a qualitative approach using a case study design. Data collection methods included observation, interviews, and field documentation, with subsequent analysis carried out through condensation techniques, data presentation, and inference drawing. Data validity was ensured through triangulation. Findings suggest that project-based learning offers students more meaningful learning experiences by engaging them in real-world projects, which are more stimulating compared to traditional passive approaches. Evaluation results indicate a noteworthy enhancement in student learning achievement following the implementation of project-based learning. In summary, project-based learning emerges as an effective strategy for improving the educational process in schools.

Micro-CT determination of the porosity of two tricalcium silicate sealers applied using three obturation techniques.

Using X-ray micro-computed tomography (micro-CT), the aim of this study was to measure the porosity of two tricalcium silicate sealers (EndoSequence BC and NeoSealer Flo) applied using three obturation techniques (single-cone, warm-vertical, and cold-lateral) to six single-rooted human teeth. Six extracted, single-rooted human teeth were shaped with ProTaper Next rotary files and obturated with EndoSequence BC or NeoSealer Flo sealers and gutta-percha (GP) using one of the three techniques above. Micro-CT was used to map the full length of the canals. Deep learning cross-sectional segmentation was used to analyze image slices of the apical (0-2 mm) and coronal (14-16 mm from the apex) regions (n = 230-261 per tooth) for the areas of GP and sealer, as well as porosity. Median (%) with interquartile range of porosity were calculated , and the results were statistically analyzed with the Kruskal-Wallis test. In the apical region, EndoSequence BC had significantly fewer pores than NeoSealer Flo with the single-cone obturation (% median-interquartile range, IQR: 0.00-1.62) and warm-vertical condensation (5.57-10.32) techniques, whereas in the coronal region, NeoSealer Flo had significantly fewer pores than EndoSequence BC with these two techniques (0.39-5.02) and (0.10-0.19), respectively. There was no significant difference in porosity between the two sealers for the cold-lateral condensation technique in both the apical and coronal regions. For optimal obturation, the choice of technique and sealer is critical.

Comparative Evaluation of Fracture Resistance of Bioceramics as Obturating Material with and without Guttapercha

Background and Aim Bioceramic sealers have revolutionized endodontic practice. However their use as obturating materials has not yet been evaluated. Therefore the present study aimed to evaluate the fracture resistance of root filled teeth obturated with bioceramic-based sealer BioRoot RCS epoxy resin AH plus and Zinc oxide eugenol ZOE based sealers with and without guttapercha using various obturation techniques.Methods Ninety human single-rooted mandibular premolar teeth were extracted decoronated and standardized to a root length of 13 mm. The teeth were instrumented using the Neoendo flex rotary system up to an apical size of 25. Subsequently the specimens were divided into three groups n30 based on the obturation materials and techniques employed. Group 1 Lateral condensation with 0.02 guttapercha LC Group 2 Single cone obturation with 0.06 gutta-percha SC Group 3 Complete sealer obturation without gutta-percha CS. Each experimental group was divided into three sub-groups n10 using following sealersA ZOE B AH plus C BioRoot RCS. The specimens were coronally sealed with Cavit mounted in an acrylic mould and fracture resistance was determined using Universal testing machine and the obtained values were tabulated. Statistical analysis was done using One-way ANOVA and post hoc Tukey tests P le0.05.Results Among the experimental groups subgroup 1C Lateral condensation with bioceramic sealer showed the highest fracture resistance and no significant difference was found between 1C and 2C Single cone GP while subgroup A ZOE showed least resistance among all groups.Conclusion The absence of gutta-percha with bioceramic sealer resulted in reduced fracture resistance. Conversely the use of gutta-percha in conjunction with bioceramic sealer through lateral condensation and single cone techniques enhanced the resistance to fracture in endodontically treated teeth.

Experiment and modeling of an improvised atmospheric water harvester for arid and semi-arid conditions

Freshwater scarcity is a severe challenge in arid and semi-arid climatic conditions wherein the water harvesting from the atmosphere using active cooling condensation technique (ACC) is the only option. In this regard, we performed extensive experiments on a classical atmospheric water harvester (AWH) that relies on moisture condensation via a typical 1TR refrigeration cycle. We developed a MATLAB-SIMULINK based AWH model to note that the classical system has reasonable water harvesting rates in humid climates, but is inadequate for arid and semi-arid climatic conditions. We add an ultrasonic humidifier (160 W power input) before the evaporator section of the classical AWH system to address this issue. The modified system only needs a small amount of water (≈250 ml) for start-up, and further operates without perpetual water supply. We measure the water overflow from the humidifier tank (subtract the water added via the humidifier from the total water harvest) to show a net water harvesting in extremely hot and dry conditions (49 °C DBT and 12 % RH) resembling the weather conditions of Jaisalmer, India. A significant improvement of up to 70 % in water harvesting was also observed under warm and dry climates (35 °C DBT and 21 % RH) mimicking Jaipur, India. We believe that our system shows path for developing active AWH systems with substantial water harvesting in arid climates where active moisture condensation using the conventional strategy is otherwise not possible.

Root canal retreatment of root canals filled with "Neo MTA 2" and epoxy resin, using continuous and asymmetric reciprocal rotation systems: In vitro study.

The study aimed to compare the amount of extrusion, the time taken to achieve apical patency and duration for removing filling material during the retreatment of teeth filled with NeoMTA 2® (Avalon Biomed, Houston, TX, USA), a calcium silicate hydraulic cement and AHPlus™ (Denstsply, Konstanz, Germany), a resin-based cement, using continuous rotation and asymmetric reciprocating rotation instruments. 60 monoradicular human teeth were selected and instrumented with Race #35.06 (FKG Dentaire, La Chaux-de-Fonds, Switzerland). The teeth were randomly assigned to two groups based on the cement used for filling (n = 30 each) AHPlus™ and NeoMTA 2®. Both groups were obturated with gutta-percha, using the lateral condensation technique. During non-surgical retreatments, each group was further divided into two subgroups: D-Race (FKG) and Reciproc (VDW, Munich, Germany) (n = 15 each). The total time to achieve apical patency and complete the retreatment were recorded. Extruded debris were collected and weighted. Student t-tests were employed for mean comparisons to assess significant differences between variables. No statistically significant differences were found in terms of type of cement and apical extrusion. Regarding the rotation system, using the Reciproc system resulted in longer time to achieve patency and retreatment times compared to D-Race system, with statistically significant differences (P< 0.05). All systems used in retreatment led to apical extrusion. Apical patency was achieved in all cases. Key words:D-Race, Reciproc, calcium silicate-based cement, root canal retreatment.

Synthesis of silver-palladium Janus nanoparticles using co-sputtering of independent sources: experimental and theorical study.

Janus-type nanoparticles are important because of their ability to combine distinct properties and functionalities in a single particle, making them extremely versatile and valuable in various scientific, technological, and industrial applications. In this work, bimetallic silver-palladium Janus nanoparticles were obtained for the first time using the inert gas condensation technique. In order to achieve this, an original synthesis equipment built by Mantis Ltd. was modified by the inclusion of an additional magnetron in a second chamber, which allowed us to use two monometallic targets to sputter the two metals independently. With this arrangement, we could find appropriate settings at room temperature to promote the synthesis of bimetallic Janus nanoparticles. The structural properties of the resulting nanoparticles were investigated by transmission electron microscopy (TEM), and the chemical composition was analyzed by TEM energy dispersive spectroscopy (TEM-EDS), which, together with structural analysis, confirmed the presence of Janus-type nanostructures. Results of molecular dynamics and TEM simulations show that the differences between the crystalline structures of the Pd and Ag regions observed in the TEM micrographs can be explained by small mismatches in the orientations of the two regions of the particle. A density functional theory structural aims to understand the atomic arrangement at the interface of the Janus particle.

Evaluation of the penetration depth of Guttaflow bioseal and Bioceramic sealers using scanning electron microscope (in vitro study).

Background and objective: Three- dimensional obturation of the canal is mandatory in root canal treatment to decrease failure rate, the major cause of root canal reinfection after obturation is insufficient obturation of the canal which later leads to a periapical lesion and reinfection.This study aimed to evaluate the penetration depth of Guttaflow bioseal and Bioceramic sealer. Methods: Twenty extracted single-rooted human teeth (mandibular first premolar) were used in this study, teeth were decornated leaving 10 mm root length. The chemico-mechanical preparation of the samples was done by using a protaper universal system till size F1 and then samples were divided into 2 groups (n = 10), according to the filling material in the first group Guttaflow bioseal used while in the second group Onefil bioceramic sealer used the sealers introduced into canals according to manufactures instructions and then obturated with gutta-percha size F1, single condensation technique used and finally samples were cross- sectioned at 3 and 7 mm, sealers penetration depth was measured by using scanning electron microscope. Result: Independent sample t-test shows that the difference between the penetration depth of guttaflow bioseal and bioceramic sealers are non-significant while the ANOVA test shows that the difference between the three sections of the root is highly significant for both sealer, coronal section shows the best result for Guttaflow bioseal while middle section for Bioceramic shows the best result of penetration. Keywords: penetration depth, Guttaflow bioseal, Bioceramic sealers, scanning electron microscope

Evaluation of the penetration depth of Guttaflow bioseal and Bioceramic sealers using scanning electron microscope (in vitro study).

Background and objective: Three-dimensional obturation of the canal is mandatory in root canal treatment to decrease failure rate, the major cause of root canal reinfection after obturation is insufficient obturation of the canal which later leads to a periapical lesion and reinfection.This study aimed to evaluate the penetration depth of Guttaflow bioseal and Bioceramic sealer. Methods: Twenty extracted single-rooted human teeth (mandibular first premolar) were used in this study, teeth were decornated leaving 10 mm root length. The chemico-mechanical preparation of the samples was done by using a protaper universal system till size F1 and then samples were divided into 2 groups (n = 10), according to the filling material in the first group Guttaflow bioseal used while in the second group Onefil bioceramic sealer used the sealers introduced into canals according to manufactures instructions and then obturated with gutta-percha size F1, single condensation technique used and finally samples were cross- sectioned at 3 and 7 mm, sealers penetration depth was measured by using scanning electron microscope. Result: Independent sample t-test shows that the difference between the penetration depth of guttaflow bioseal and bioceramic sealers are non-significant while the ANOVA test shows that the difference between the three sections of the root is highly significant for both sealer, coronal section shows the best result for Guttaflow bioseal while middle section for Bioceramic shows the best result of penetration. Conclusion: There are no difference in sealer penetration of both sealers Guttaflow bioseal and Onefil bioceramic, while regarding sealer penetration in each sections of root for Guttaflow bioseal in coronal section shows a best penetration, for Onefil bioceramic middle section shows a best penetration.

Stress Relaxation of Extremely-Thin-Body Ge-on-Insulator p-Type Metal-Oxide-Semiconductor Field-Effect Transistor Along and Observed By Oil-Immersion Raman Spectroscopy

Background and purpose Strain techniques and channel materials with high carrier mobility are the principal technology boosters for the realization of high-performance logic devices composed of group IV semiconductors such as silicon (Si). In particular, strain engineering plays an important role in improving the performance of metal-oxide semiconductor field-effect transistors (MOSFETs) from the viewpoint of reducing the effective carrier mass. It is important to evaluate the stress relaxation in group IV semiconductor devices for the optimization of the carrier mobility and the device structure. In this paper, we demonstrated the stress evaluation of extremely-thin-body Ge-on-insulator (ETB GOI) p-type MOSFET along the <110> and <100> longitudinal directions by oil-immersion Raman spectroscopy with the high-numerical-aperture (high-NA) lens to realize precise evaluation of strain states in the Ge channels. Experiments Biaxially-strained (001) GOI layer was prepared by applying optimized Ge condensation technique on epitaxially-grown Si/Si0.75Ge0.25/Si-on-insulator substrates with 4-hour slow cooling [1, 2]. After the removal of the thermal oxide, narrow channel patterning was performed by electron-beam (EB) lithography. GOI channel was further thinned down by the cyclic digital etching process (plasma oxidation and wet etching). Surface passivation process was then immediately performed to fabricate GeO x and Al2O3 by plasma oxidation and atomic layer deposition at 300oC, respectively. The source-drain regions were formed with EB evaporated Ni through a lift-off process and Al deposition was performed as the back gate electrode.We used the Raman spectrometer with spectrograph focal length of 2,000 mm. The numbers of grating grooves were 2,400 mm-1 and a visible laser was used as the incident excitation light source whose wavelength was 532 nm. To realize anisotropic stress evaluation assuming the channel region of the ETB GOI MOSFET, we used a high-NA immersion lens for the selective excitation of both LO and TO phonon modes [3]. The high-NA and refractive index n of the oil were approximately 1.4 and 1.5, respectively. Using a high-NA immersion lens, a z-polarized light component can be effectively obtained owing to the aperture angle. Therefore, TO phonons can be excited on the basis of Raman selection rules for (001)-oriented GOI [3, 4]. Results and discussion Figure 1 shows the channel width dependence of the anisotropic biaxial stress of ETB GOI MOSFET along the <100> longitudinal direction obtained by the oil-immersion Raman spectra. Anisotropic biaxial compressive stress at the GOI channel width direction of the GOI channels was observed even when the GOI channel width is wide (GOI channel width ~ 630 nm). The stress along the GOI channel length (the <100> longitudinal direction) is relatively high. These results are clearly different from the stress relaxation in the ETB GOI MOSFET along the <110> longitudinal direction. In previous studies, a clear stress relaxation at the GOI channel width direction was observed as the GOI channel width becomes narrower of the ETB GOI MOSFET along the <110> longitudinal direction (from channel width ~ 200 nm) [5]. The results observed in this study are generally well correlated with the results obtained in strain relaxation measurements of carbon-doped Si nanowires along <100> by X-ray diffraction with synchrotron radiation [6]. The difference in the strain relaxation mechanism depending on the GOI channel direction may affect the electrical properties, and we consider that it is useful to be physical elucidation of the carrier mobility enhancement. Acknowledgements This work was supported by JSPS KAKENHI Grant Number 22H00208, Japan. A part of this work was con-ducted at Takeda Sentanchi Supercleanroom, The University of Tokyo, supported by "Nanotechnology Platform Program" of MEXT, Japan, Grant Number JPMXP09F-20-UT-0007.