Calcium Silicate-Based Cements in Restorative Dentistry: Vital Pulp Therapy Clinical, Radiographic, and Histological Outcomes on Deciduous and Permanent Dentition-A Systematic Review and Meta-Analysis.

Vital pulp therapy aims to preserve the vitality of dental pulp exposed due to caries, trauma, or restorative procedures. The aim of the present review was to evaluate the clinical, radiographic, and histological outcomes of different calcium silicate-based cements used in vital pulp therapy for both primary and permanent teeth. The review included 40 randomized controlled trials from a search across PubMed, LILACS, and the Cochrane Collaboration, as well as manual searches and author inquiries according to specific inclusion and exclusion criteria. A critical assessment of studies was conducted, and after data extraction the results were submitted to a quantitative statistical analysis using meta-analysis. The studies, involving 1701 patients and 3168 teeth, compared a total of 18 different calcium silicate-based cements in both dentitions. The qualitative synthesis showed no significant differences in short-term outcomes (up to 6 months) between different calcium silicate-based cements in primary teeth. ProRoot MTA and Biodentine showed similar clinical and radiographic success rates at 6 and 12 months. In permanent teeth, although the global results appeared to be well balanced, ProRoot MTA generally seemed to perform better than other calcium silicate-based cements except for Biodentine, which had comparable or superior results at 6 months. Meta-analyses for selected comparisons showed no significant differences in clinical and radiographic outcomes between ProRoot MTA and Biodentine over follow-up periods. The present review highlights the need for standardized definitions of success and follow-up periods in future studies to better guide clinical decisions. Despite the introduction of new calcium silicate-based cements aiming to address limitations of the original MTA. ProRoot MTA and Biodentine remain the most used and reliable materials for vital pulp therapy, although the results did not deviate that much from the other calcium silicate-based cements. Further long-term studies are required to establish the optimal CSC for each clinical scenario in both dentitions.

Multimethod Analysis of a Novel Multi-coloured Heat-treated Nickel-Titanium Rotary System: Design, Metallurgy, Mechanical Properties, and Shaping Ability.

INTRODUCTION: This study aimed to compare a new multicolored rotary system with four heat-treated rotary instruments using the multimethod approach. METHODS: Three-hundred instruments of RCS Rainbow, Rotate, RaCe EVO, OneCurve, and ProTaper Ultimate systems were evaluated regarding their design (stereomicroscopy, scanning electron microscopy, and 3D surface scanning), metallurgy, and mechanical performance (cyclic fatigue, torsional resistance, bending and buckling resistance, and cutting ability). Unprepared surfaces after canal preparation of maxillary molars were evaluated using micro-computed tomography. Kruskal-Wallis and one-way analysis of variance post hoc Tukey tests were used for statistical comparisons (α = 5%). RESULTS: Instruments exhibited variations in active blade length, number of spirals, and cross-sectional designs. RCS Rainbow showed specific phase transformation temperatures, highest bending (400.5gf) and buckling (286gf) resistance values, and lowest mean angle of rotation (529°) (P < .05). OneCurve exhibited superior cutting ability (8.4 mm) and longer time to fracture (112s). RaCe EVO displayed the lowest time to fracture (51s), maximum torque (1.2 N.cm), buckling (174gf), and bending resistance (261gf) values (P < .05). ProTaper Ultimate showed the highest torque (1.6 N.cm) and angle of rotation (611°) (P < .05), while its bending load (262gf) was comparable to RaCe EVO (P > .05). Rotate instrument showed intermediate values in the mechanical tests. No difference was observed regarding the unprepared canal surfaces (P > .05) CONCLUSIONS: RCS Rainbow demonstrates a trade-off between flexibility and other mechanical properties. Its dimensions exceeded those of other instruments, affording it higher torque resistance, yet concurrently reducing its flexibility, angle of rotation, and cutting ability. OneCurve stands out as a well-balanced choice by integrating geometric design and mechanical performance.

A qualitative exploration of the impact of the COVID-19 pandemic on gender-based violence against women living with HIV or tuberculosis in Timor Leste.

Violence against women or gender-based violence (GBV) is a significant public health issue facing women and girls in different settings. It is reported to have worsened globally during the COVID-19 pandemic. Despite the impact of the COVID-19 pandemic on increased violence against women in general, which has been reported in many settings globally, there is a paucity of evidence of its impact on violence against highly vulnerable women living with HIV or tuberculosis (TB). Using a qualitative design, this study aimed to explore the views and experiences of women living with HIV (n = 19) or TB (n = 23) in Timor Leste regarding the GBV they faced during the COVID-19 pandemic. They were recruited using the snowballing sampling technique. Data were collected using one-on-one, in-depth interviews and focus group discussions. The five steps of qualitative data analysis suggested in Ritchie and Spencer's analysis framework were employed to guide the analysis of the findings. Findings indicated that women in this study experienced intensified physical, verbal, sexual and psychological violence by their partners, spouses, in-laws, and parents or other family members during the COVID-19 pandemic. Several prominent risk factors that worsened violence against women during the pandemic were (i) HIV or TB-positive status, (ii) traditional gender roles or responsibilities and expectations, (iii) economic and financial difficulties reflected in the loss of jobs and incomes due to the pandemic, and (iv) individual factors such as jealousy and increased alcohol drinking developed during the lockdowns. The women's experience of GBV during the pandemic also led to various negative psychological impacts. The findings underscore the urgent need for multifaceted interventions to address GBV, which should encompass challenging traditional gender norms, addressing economic inequalities, and targeting individual-level risk factors. The findings also indicate the need for the development of robust monitoring and evaluation systems to assess the effectiveness of policies and interventions addressing GBV where the results can inform future improvement. The findings also indicate the need to include GBV in the protocol or guidelines for HIV and TB management. Future large-scale quantitative studies to capture the magnitude and specific drivers of GBV against women living with HIV and TB during the pandemic are recommended.

Effect of Lignosulphonates on the Moisture Resistance of Phenol-Formaldehyde Resins for Exterior Plywood.

Phenol-formaldehyde (PF) resins remain the preferred adhesive for exterior plywood, as they confer these boards their extreme weather resistance. However, their high price and toxicity has made phenol alternatives, such as technical lignins, increasingly more attractive. While many works report the use of kraft lignin, the most commercially available form are lignosulphonates (LS). However, these lack industrial success and are associated with low moisture resistance. In the current study, lignosulphonate-phenol-formaldehyde (LPF) resoles were synthesized considering a phenol replacement of 30% (w/w). Two LS samples of softwood (SLS) and hardwood (HLS) origin were compared. These samples were previously methylolated to increase their reactivity. The effectiveness of the treatment was confirmed through the Automated Bonding Evaluation System. Plywood was manufactured and tested according to EN 314 class 3 for exterior conditions, which is seldom found in the literature. Although a 35% increase in shear strength is still necessary to comply with the standard, methylolated SLS was the most promising substitute, as it resulted in the highest board performance. Notably, when this sample was used without previous methylolation, the plywood boards suffered delamination during immersion in boiling water prior to shear testing. These results reinforce the need for the methylolation of LS to increase the weather resistance of plywood.

Worldwide Prevalence of Single-rooted with a Single Root Canal and Four-rooted Configurations in Maxillary Molars: A Multi-center Cross-sectional Study with Meta-analysis.

INTRODUCTION: To evaluate the prevalence of single root with a single root canal and four-root configurations in the maxillary first and second molars, and analyze how geographic region, ethnicity, sex, and age impact these outcomes. METHODS: Researchers from 44 nations examined 26,400 maxillary molars using cone-beam computed tomography scans to gather data on the proportions of single roots with single canals and four-root configurations. All observers underwent prior calibration regarding the step-by-step assessment protocol and anatomical concepts to ensure consistent evaluations across all assessed locations. Tests were conducted to evaluate the intraobserver and interobserver reliability. Demographic data including ethnicity, gender, and age were collected for each participant. The potential impact of imaging voxel size and field-of-view on bias was also assessed. The primary results were depicted as odds ratios and untransformed proportion forest plots with 95% confidence intervals. Additionally, a meta-analysis was performed to compare various subgroups and identify sources of variation among them. Statistical significance was set at 5%. RESULTS: The prevalence of single-rooted with a single canal and four-rooted configurations in the maxillary first molar was 0.16% and 0.28%, respectively, while in the maxillary second molar, it was 2.56% and 0.83%. Males tended to exhibit lower percentages of single roots with a single canal (P < .05) and higher percentages of four-rooted configurations (P > .05) in the second molar, whereas the African subgroup displayed lower proportions for both configurations. Additionally, in both teeth, single roots with a single canal were more prevalent among older patients. Voxel size and field-of-view did not significantly influence the results (P > .05). CONCLUSIONS: The proportions of single-rooted with a single canal and four-rooted configurations were low, and demographic factors such as geographic region, ethnicity, sex, and age may have influenced the outcomes for the maxillary second molar.

Brain correlates and functional connectivity linking stress, autonomic dysregulation, and alcohol motivation.

High stress is a key risk factor for alcohol use disorder (AUD) and often accompanied by physiological dysregulation including autonomic nervous system (ANS) disruptions. However, neural mechanisms underlying drinking behaviors associated with stress and ANS disruptions remain unclear. The current study aims to understand neural correlates of stress, ANS disruptions, and subsequent alcohol intake in social drinkers with risky drinking. Using functional magnetic resonance imaging (fMRI), we investigated brain and heart rate (HR) autonomic responses during brief exposure to stress, alcohol, and neutral cues utilizing a well-validated, individualized imagery paradigm in 48 social drinkers of which 26 reported high-risk drinking (HD) while 22 reported low-risk drinking (LD) patterns. Results indicated that HD individuals showed stress and ANS disruptions with increased basal HR, stress-induced craving, and decreased brain response to stress exposure in frontal-striatal regions including the ventromedial prefrontal cortex (VmPFC), anterior cingulate cortex, striatum, insula, and temporal gyrus. Furthermore, whole-brain correlation analysis indicated that greater basal HR was associated with hypoactive VmPFC, but hyperactive medulla oblongata (MOb) responses during stress, with an inverse association between activity in the VmPFC and Mob (whole-brain corrected (WBC), p < 0.05). Functional connectivity with the MOb as a seed to the whole brain indicated that HD versus LD had decreased functional connectivity between the VmPFC and MOb during stress (WBC, p < 0.05). In addition, those with more compromised functional connectivity between the VmPFC and MOb during stress consumed greater amount of alcohol beverage during an experimental alcohol taste test conducted on a separate day, as well as in their self-reported weekly alcohol intake. Together, these results indicate that stress-related, dysfunctional VmPFC control over brain regions of autonomic arousal contributes to greater alcohol motivation and may be a significant risk factor for hazardous alcohol use in non-dependent social drinkers. Findings also suggest that restoring VmPFC integrity in modulating autonomic arousal during stress may be critical for preventing the development of AUD.

Multi-Force Bio-Active™ Archwires and Various Contemporary NiTi Multi-Force Archwires: Properties and Characteristics-A Review.

The manufacturing of orthodontic archwires made from NiTi alloy has undergone numerous changes from the second half of the last century to modern times. Initially, superelastic-active austenitic NiTi alloys were predominant, followed by thermodynamic-active martensitic NiTi alloys, and, finally, the most recent development was graded thermodynamic alloys. These advancements have been the subject of extensive investigation in numerous studies, as they necessitated a deeper understanding of their properties. Furthermore, it is imperative that we validate the information provided by manufacturers regarding these archwires through independent studies. This review evaluates existing studies on the subject with a specific focus on the Bio-active multi-force NiTi archwire, by examining its mechanical, thermal, and physicochemical properties before and after clinical use. This archwire consists primarily of Ni and Ti, with traces of Fe and Cr, which release graduated, biologically tolerable forces which increase in a front-to-back direction and are affected by the temperature of the environment they are in. The review provides information to practicing orthodontists, facilitating informed decisions regarding the selection and use of Bio-active™ archwires for individual patient treatments.

Comprehensive Assessment of Cyclic Fatigue Strength in Five Multiple-File Nickel-Titanium Endodontic Systems.

The resistance of nickel-titanium endodontic instruments against cyclic fatigue failure remains a significant concern in clinical settings. This study aimed to assess the cyclic fatigue strength of five nickel-titanium rotary systems, while correlating the results with the instruments' geometric and metallurgical characteristics. A total of 250 new instruments (sizes S1/A1, S2/A2, F1/B1, F2/B2, F3/B3) from ProTaper Gold, ProTaper Universal, Premium Taper Gold, Go-Taper Flex, and U-Files systems underwent mechanical testing. Prior to experimental procedures, all instruments were meticulously inspected to identify irregularities that could affect the investigation. Using a stereomicroscope, design characteristics such as the number of spirals, length, spirals per millimeter, and average helical angle of the active blade were determined. The surface finishing characteristics of the instruments were examined using a scanning electron microscope. Differential scanning calorimetry was employed to establish the instruments' phase transformation temperatures, while energy-dispersive X-ray spectroscopy was utilized to analyze the elemental composition of the alloy. The instruments were subjected to cyclic fatigue testing within a stainless steel non-tapered artificial canal featuring a 6 mm radius and 86 degrees of curvature. Appropriate statistical tests were applied to compare groups, considering a significance level of 0.05. The assessed design characteristics varied depending on the instrument type. The least irregular surface finishing was observed in U-Files and Premium Taper Gold files, while the most irregular surface was noted in Go-Taper Flex. All instruments exhibited near-equiatomic proportions of nickel and titanium elements, whereas ProTaper Universal and U-Files instruments demonstrated lower phase transformation temperatures compared to their counterparts. Larger-sized instruments, as well as ProTaper Universal and U-Files, tended to display lower cyclic fatigue strength results. Overall, the design, metallurgical, and cyclic fatigue outcomes varied among instruments and systems. Understanding these outcomes may assist clinicians in making more informed decisions regarding instrument selection.

Influence of root shape on canal complexity at the mandibular molar apical surgical resection level: A micro-CT study.

OBJECTIVES: This study aimed to investigate the relationship between the aspect ratios of mandibular molar roots at the apical 3-mm level and their root canal complexity. DESIGN: This study used micro-CT imaging to analyze 163 two-rooted mandibular molars. The aspect ratios of the roots at the apical 3-mm level were categorized as "< 2.75" or "≥ 2.75" (mesial) and "< 1.75" or "≥ 1.75" (distal). A two-dimensional (2D) analysis focused on four apical axial cross-section levels to determine the presence of main and accessory canals and isthmus. Additionally, a three-dimensional (3D) assessment of the apical 4-mm of both roots examined main and accessory canals, apical foramina, apical deltas, and middle mesial canals. RESULTS: Mesial roots with aspect ratios ≥ 2.75 showed a higher number of main canals at all levels compared to those with aspect ratios < 2.75 at the 3-mm level. Additionally, the ≥ 2.75 group exhibited more accessory canals and a higher average number of accessory canals. The 3D assessment confirmed significantly more accessory canals and apical foramina in the ≥ 2.75 group. The prevalence of roots with apical deltas was nearly double in the ≥ 2.75 group, and middle mesial canals were exclusively found in this group. In the distal root, the ≥ 1.75 group showed a significantly higher number of main canals at all axial levels. No significant differences were observed between groups in terms of accessory canals, apical foramina, or deltas. CONCLUSIONS: A higher root aspect ratio is related to higher anatomical complexity.

Comparative Analysis of Endodontic ISO Size 06, 08, and 10 Stainless Steel K-Files Used for Glide Path Procedures.

Small-sized stainless steel hand files are conventionally employed in root canal treatment procedures for canal scouting and for glide path establishment, owing to their superior flexibility and proficiency in navigating confined spaces. Given the diversity of brands available in the market, there exists potential variability in their physical characteristics, thereby influencing clinical performance. Consequently, this study aims to conduct a comparative analysis of the design, metallurgy, and mechanical characteristics among seven stainless steel hand file brands across ISO sizes 06, 08, and 10. A total of 315 new 25 mm length stainless steel hand files with apical sizes of 0.06, 0.08, and 0.10 from seven distinct brands were included in the study. A meticulous inspection of all instruments was undertaken to identify any structural deformations that might render them ineligible for the study. The design inspection involved the random selection of instruments from each group, which were examined under various microscopes, including a dental operating microscope, optical microscope, and scanning electron microscope. Furthermore, two instruments from each group underwent energy-dispersive X-ray spectroscopy analysis for elemental composition documentation. Mechanical tests were conducted to evaluate the instruments' resistance to lateral deformation (buckling) and their microhardness. Statistical analysis was executed using the nonparametric Mood's median test, with a predetermined significance level of 0.05. Regarding the instruments design, all files exhibited an active blade length ranging from 16 to 17 mm. However, variations were observed in the number of spirals, tip designs, and sizes, with the API K-File notably larger in sizes 0.06 and 0.08 compared to the other instruments. Despite uniform elements composition, differences in geometric features and mechanical properties were evident. Concerning buckling strength, the API K-File demonstrated superior performance across all tested sizes, while the Dentsply ReadySteel, SybronEndo, and Mani K-Files exhibited lower results (p < 0.05). In microhardness assessments, both the API and Oro K-Files displayed the lowest outcomes, with medians of 531 HVN and 532 HVN, respectively, whereas the SybronEndo K-File exhibited the highest microhardness (657 HVN). Despite similar metallurgical composition, the observed distinctions in geometric features and mechanical properties underscore the impact of the manufacturing process on the characteristics of glide path stainless steel endodontic files. These disparities may ultimately influence their clinical performance.

Site selection for nature-based solutions for stormwater management in urban areas: An approach combining GIS and multi-criteria analysis.

In recent years, particularly following the definition of the UN Sustainable Development Goals (SDGs) for 2030, Nature-Based Solutions (NBS) have gained considerable attention, capturing the interest of both the scientific community and policymakers committed to addressing urban environmental issues. However, the need for studies to guide decision-makers in identifying suitable locations for NBS implementation within urban stormwater management is evident. To address this gap, the present study employs a methodological approach grounded in multi-criteria analysis integrated with Geographic Information Systems (GIS) to identify areas with potential for NBS implementation. In this process, ten NBS were proposed and tested in the drainage area of a shallow tropical urban lake in Londrina, southern Brazil. Additionally, the study investigates areas hosting lower-income populations, a relevant aspect for public managers given the diverse economic subsidies required to implement NBS. Furthermore, the study incorporates a preliminary analysis that evaluates the potential ecosystem benefits to determine the most suitable NBS for a specific site. The result shows that all the ten analyzed NBS were deemed suitable for the study area. Rain barrels had the highest percentage coverage in the study area (37.1%), followed by tree pits (27.9%), and rain gardens (25.4%). Despite having the highest distribution in the basin area, rain barrels exhibited only moderate ecosystem benefits, prompting the prioritization of other NBS with more significant ecological advantages in the final integrated map. In summary, the methodology proposed showed to be a robust approach to selecting optimal solutions in densely populated urban areas.

Sperm traits and seminal plasma proteome of locally adapted hairy rams subjected to intermittent scrotal insulation.

The present study evaluated the effects of heat stress on reproductive parameters of hairy rams. Six animals were subjected to scrotal insulation during four consecutive nights (6 PM - 6 AM). Day (D) 0 was the first day of insulation. Scrotal circumference increased from 30.5 ± 0.3 cm (at pre-insulation) to 31.8 ± 0.4 cm on D4, decreased 3.9 cm on D28, returning to 30.6 ± 0.6 cm on D57. Sperm concentration decreased from 3.7 ± 0.12 ×109 sperm/mL before insulation to 2.6 ± 0.1 ×109 on D23, returning to normal on D57. Sperm motility averaged 75 ± 2.9% before insulation, was undetectable on D23, and became normal on D77. Sperm with normal morphology reached 5.9 ± 2.6% on D35 but recovered (86.8 ± 2.1%) on D91. Sperm DNA integrity decreased from 86.5 ± 4.7% before insulation to 11.1 ± 3.7% on D63, returning to pre-insulation values on D120. Sperm BSP immunostaining was reduced after scrotal insulation. Variations in seminal protein abundances coincided with changes in sperm parameters. Seminal plasma superoxide dismutase, carboxypeptidase Q-precursor and NPC intracellular cholesterol transporter 2 decreased on D18, returning to normal after D28. Albumin, inhibitor of carbonic anhydrase precursor, EGF-like repeat and discoid I-like domain-containing protein 3 and polymeric immunoglobulin receptor increased after insulation. In summary, intermittent scrotal insulation drastically altered ram sperm attributes and seminal proteins, especially those associated with oxidative stress. Knowledge of animal´s response to thermal stress is vital in the scenario of climate changes.

Diagnostic value of cone beam computed tomography for root canal morphology assessment - a micro-CT based comparison.

OBJECTIVES: The aim of this study was to assess cone beam computed tomography (CBCT) as a root canal anatomy diagnostic tool by comparison with micro-CT gold-standard. MATERIALS AND METHODS: 216 two-rooted mandibular molars were first scanned in a CBCT device (200 µm voxel size) and posteriorly in a micro-CT scanner (19.61 µm). The volumes were sequentially screened to classify main root canal anatomy according to Vertucci classification, and for the presence of lateral canals and apical deltas, in both mesial and distal roots. RESULTS: Both methods revealed a higher prevalence of Vertucci Type II and IV in the mesial root, and Vertucci Type I in the distal root. The percentage of agreement for main root canal anatomy classification between CBCT and micro-CT scores was high (85.2%). CONCLUSION: Sensibility to detect both lateral canals and apical deltas with CBCT was low. These results attest to the fact that minor anatomical changes might be difficult to identify with CBCT imaging, hampering its diagnostic value.

Multimethod analysis of large- and low-tapered single file reciprocating instruments: Design, metallurgy, mechanical performance, and irrigation flow.

AIM: To compare eight large- and low-tapered heat-treated reciprocating instruments regarding their design, metallurgy, mechanical properties, and irrigation flow through an in silico model. METHODOLOGY: A total of 472 new 25-mm E-Flex Rex (25/.04 and 25/.06), Excalibur (25/.05), Procodile (25/.06), Reciproc Blue R25 (25/.08v), WaveOne Gold Primary (25/.07v), and Univy Sense (25/.04 and 25/.06) instruments were evaluated regarding their design (stereomicroscopy, scanning electron microscopy, and 3D surface scanning), metallurgy (energy-dispersive X-ray spectroscopy and differential scanning calorimetry), and mechanical performance (cyclic fatigue, torsional resistance, cutting ability, bending and buckling resistance). Computational fluid dynamics assessment was also conducted to determine the irrigation flow pattern, apical pressure, and wall shear stress in simulated canal preparations. Kruskal-Wallis and one-way anova post hoc Tukey tests were used for statistical comparisons (α = 5%). RESULTS: Instruments presented variations in blade numbers, helical angles, and tip designs, with all featuring non-active tips, symmetrical blades, and equiatomic nickel-titanium ratios. Cross-sectional designs exhibited an S-shaped geometry, except for WaveOne Gold. Univy 25/.04 and Reciproc Blue displayed the smallest and largest core diameters at D3. Univy 25/.04 and E-Flex Rec 25/.04 demonstrated the longest time to fracture (p < .05). Reciproc Blue and Univy 25/.04 exhibited the highest and lowest torque to fracture, respectively (p < .05). Univy 25/.04 and Reciproc Blue had the highest rotation angles, whilst E-Flex Rec 25/.06 showed the lowest angle (p < .05). The better cutting ability was observed with E-Flex Rec 25/.06, Procodile, Excalibur, and Reciproc Blue (p > .05). Reciproc R25 and E-Flex Rec showed the highest buckling resistance values (p < .05), with WaveOne Gold being the least flexible instrument. The impact of instruments' size and taper on wall shear stress and apical pressure did not follow a distinct pattern, although Univy 25/.04 and E-Flex Rec 25/.06 yielded the highest and lowest values for both parameters, respectively. CONCLUSIONS: Low-tapered reciprocating instruments exhibit increased flexibility, higher time to fracture, and greater angles of rotation, coupled with reduced maximum bending loads and buckling strength compared to large-tapered instruments. Nevertheless, low-tapered systems also exhibit lower maximum torque to fracture and inferior cutting ability, contributing to a narrower apical canal enlargement that may compromise the penetration of irrigants in that region.

Gas-diffusion microextraction combined with HPLC-DAD for the comprehensive analysis of volatile carbonyl compounds in wood-based panels.

This work presents a novel application of gas-diffusion microextraction (GDME) combined with high-performance liquid chromatography with diode-array detection (HPLC-DAD) for the comprehensive analysis of volatile carbonyl compounds released from wood-based panels. GDME is a simple, fast, and environmentally friendly technique that allows the simultaneous extraction and derivatization of volatile carbonyls directly from solid samples. Commercial particleboards were analysed together with particleboard panels specifically produced using controlled conditions, materials, and reagents, to evaluate the differences in the emission profile of volatile carbonyl compounds. The effect of different production parameters, such as the type of wood particle, resin, and moisture content, on the emission profile of volatile carbonyls from particleboards was investigated using principal component analysis (PCA). The results showed that GDME-HPLC-DAD could successfully differentiate particleboards according to their emission of carbonyl compounds, such as formaldehyde, furfural, benzaldehyde, and other aliphatic carbonyls. Besides the differences on the emission of formaldehyde caused by the type of resin used, UF (urea-formaldehyde) and mUF (UF fortified with melamine), it was found that pine (Pinus pinaster Ait.) particleboards exhibit higher emissions of compounds such as acetaldehyde or hexanal when compared to the higher emissions of compounds such as furfural or benzaldehyde on the recycled particleboards.

Comparative Analysis of Endodontic 0.15 Stainless-Steel K-Files: Exploring Design, Composition, and Mechanical Performance.

To establish a glide path, smaller files (up to size 0.15) with tapers of 2% are commonly used as pathfinding files. They pre-shape the root canal space before transitioning to larger taper endodontic instruments, aiming to prevent procedural errors. This study aimed to compare the design, metal wire composition, and mechanical characteristics of seven different ISO size 15 stainless-steel hand files (K-File and C-File+). Ninety-one new stainless-steel ISO 15 K-files were mechanically tested. All files were inspected for deformations before the assessment. Dental operating microscope, scanning electron microscope (SEM), and optical microscope analyses were conducted on four randomly selected instruments from each group, and two instruments per group underwent an energy-dispersive X-ray spectroscopy (EDS) analysis. Buckling mechanical tests were performed using an Instron universal testing machine, and microhardness was assessed using a Vickers hardness tester. The statistical analysis employed the nonparametric Mood's median test, with a significance level set at 0.05. The instrument design analysis unveiled variations in the active blade area length and the number of spirals, while maintaining consistent cross-sections and symmetrical blades. Distinct tip geometries and surface irregularities were observed. While the energy-dispersive X-ray spectroscopy confirmed similar compositions, the buckling strength and microhardness values exhibited variability across for all tested files. Notably, the Dentsply ReadySteel C-File+ recorded the highest buckling value (2.10 N), and the Dentsply ReadySteel K-File exhibited the lowest (1.00 N) (p < 0.05). Moreover, the Dentsply ReadySteel K-File recorded the highest microhardness value (703 HVN), while the SybronEndo Triple-Flex had the lowest (549 HVN) (p < 0.05). While similarities in cross-section design and metal wire composition were noted among the files, variations in the number of spirals and mechanical performance were also observed. Thus, all of these factors should be considered when selecting suitable files for an efficient root canal treatment.

Worldwide Anatomic Characteristics of the Mandibular Canine-A Multicenter Cross-Sectional Study with Meta-Analysis.

INTRODUCTION: This study aimed to examine the global prevalence of root and root canal morphologies in mandibular canines and analyze potential influences of region, ethnicity, sex, and age on the proportion of a second root and root canal configuration. METHODS: Observers from 44 countries screened 13,200 canines using cone-beam computed tomographic exams and gathered data on the percentages of 2 root canal morphologies and 2-rooted configurations (primary outcomes), as well as the root canal configurations (secondary outcome). Demographic factors (ethnicity, sex, and age) were collected for each participant. Primary outcomes were represented as odds ratios and untransformed proportions accompanied by 95% confidence interval (CI) forest plots. Meta-analysis compared subgroups and identified sources of heterogeneity. Intra- and inter-rater tests were conducted. Statistical significance was set at 5%. RESULTS: The worldwide prevalence of a second canal was 7.5% (95% CI, 6.3%-8.7%), ranging from 0.7% in Nigeria to 17.7% in Uruguay. The meta-analysis also revealed significant variations when comparing ethnicity, gender, and age (P < .05). The global prevalence of a second root was 1.9% (95% CI, 1.5%-2.3%), with the highest proportion observed in Spain (6.7%). Caucasian and Indian (south Asian) ethnic groups, females, and older patients exhibited higher proportions of 2 roots (P < .05). Meta-regression excluded side, voxel size, and field of view as sources of heterogeneity (P > .05). CONCLUSIONS: The prevalence of 2 root canals and 2-rooted configurations in the mandibular canine exhibited variations based on geographic location, ethnicity, sex, and age. The global prevalence of 2 root canals and 2-root configuration was 7.5% and 1.9%, respectively.

Syringe irrigation in confluent canals: A sequential computational fluid dynamics assessment.

This study aims to assess the influence of root canal preparation, irrigation needle design and its placement depth in the irrigation flow of confluent canals during syringe irrigation. A mandibular molar presenting two confluent canals in its mesial root was sequentially prepared and scanned by micro-computed tomography after mechanical preparation up to ProTaper Next system sizes X2 (25/.06v), X3 (30/.07v) and X4 (40/.06v). In each of the root canal preparation models, a side-vented and an open-ended needle at 5, 3 and 2 mm from the working length were included, and irrigation flow was assessed by a validated computational fluid dynamics model. The results revealed that the irrigant flowed out of the confluent canals mainly through the canal that did not have the needle. Apical penetration and renewal of the irrigant were most efficiently achieved with the use of a 30G open-ended needle and a 30/.07v preparation.

Worldwide Assessment of the Root and Root Canal Characteristics of Maxillary Premolars - A Multi-center Cone-beam Computed Tomography Cross-sectional Study With Meta-analysis.

INTRODUCTION: This worldwide study examined the root and root canal characteristics of maxillary premolars and explored how demographic factors impact the outcomes. METHODS: Observers from 44 countries assessed 26,400 maxillary premolars using cone-beam computed tomography and employed a standardized screening method to gather data on multiple canal morphology and 3-rooted configuration (primary outcomes), as well as secondary outcomes related to root and root canal anatomies. Demographic factors such as ethnicity, sex, and age were collected for each participant. The intra- and inter-observer tests ensured observer reliability. Primary outcomes were represented as odds ratios and untransformed proportions accompanied by 95% confidence interval (CI) forest plots. Meta-analysis compared sub-groups and identified sources of heterogeneity (α = 5%). RESULTS: The overall prevalence of multiple canal morphology in the first premolar was 93.5% (95% CI, 93.3%-94.7%), while in the second premolar, it was 49.7% (95% CI, 44.9%-54.6%). The proportion of 3-rooted configuration was 1.8% (95% CI, 1.4%-2.1%) in the first premolar and 0.4% (95% CI, 0.3%-0.5%) in the second. Asian countries generally displayed fewer roots and root canals, while European nations showed higher counts (P < .05). Males exhibited higher percentages and odds ratios for both outcomes in both premolars. Younger patients demonstrated lower percentages of multiple root canal morphologies (P < .05). Factors such as tooth side, voxel size and field-of-view did not influence the outcomes (P > .05). CONCLUSIONS: The worldwide assessment of root and root canal characteristics of maxillary premolars has revealed a discernible influence of various factors such as tooth type, geographical region, ethnicity, sex, and age.