Comparison of Easydo Activator, Ultrasonic and Needle Irrigation Techniques on Sealer Penetration in Extracted Human Teeth

This study compared the effects of different irrigation systems on sealer penetration at the root apex. Forty-two single-rooted teeth were prepared and randomly divided into three groups (n = 14): group 1: needle irrigation (NI); group 2: passive ultrasonic irrigation (PUI); and group 3: Easydo Activator (EA). A solution of 3% sodium hypochlorite (NaOCl) was used for irrigation. Nine teeth in each group were filled with AH Plus sealer mixed with CY5 fluorescent dye and a single gutta-percha cone. The sealer penetration area, maximum penetration depth and percentage of sealer penetration at 5 mm and 1 mm from the apex were analyzed by confocal laser scanning microscopy (CLSM). The remaining 5 teeth in each group were subjected to test smear layer scores by scanning electron microscopy (SEM). The CLSM evaluation showed that increases in the area, depth and percentage of sealer penetration were detected at 1 mm and 5 mm from the root apex in the PUI group compared with the NI group, and greater increases were observed in the EA group (P < 0.05). The SEM experiment showed that the lowest scores for the smear layer and debris removal were achieved by the EA group when compared with the PUI and NI groups (P < 0.05). Our study supports EA was superior to PUI and NI regarding sealer penetration at the root apex during endodontic treatment, and it could provide a new technical idea for clinical root canal therapy.

Hypoxia-Induced Ethanol Production in Arabidopsis Root Apex Cells Affects Endocytic Vesicle Recycling and F-Actin Organisation

Ethanol (EtOH) is a short-chain alcohol that is abundant in nature. EtOH is endogenously produced by plants under hypoxic conditions, and exogenously applied EtOH improves plant stress tolerance at low concentrations (<1%). However, no direct observations have shown how EtOH affects cellular events in plants. In intact Arabidopsis roots, 0.1% EtOH promoted reactive oxygen species production in root apex cells. EtOH also accelerated exocytic vesicle recycling and altered F-actin organisation, both of which are closely related to cell membrane properties. In addition to exogenous EtOH application, hypoxic treatment resulted in EtOH production in roots and degradation of the cross-wall actin cytoskeleton in root epidermal cells. We conclude that hypoxia-induced EtOH production affects endocytic vesicle recycling and associated signalling pathways.

Cellular and gene expression patterns associated with root bifurcation in Selaginella

The roots of lycophytes branch through dichotomy or bifurcation, which means that the root apex splits into two daughter roots. This is morphologically distinct from lateral root (LR) branching in the extant euphyllophytes, where LRs develop along the root axis at different distances from the apex. The process of root bifurcation is poorly understood, while such knowledge can be important, as it may represent an evolutionarily ancient strategy that roots recruited to form new stem cells or meristems. In this study, we examined root bifurcation in the lycophyte Selaginella moellendorffii. We characterized an in vitro developmental time-frame based on repetitive apex bifurcations, allowing us to sample different stages of dichotomous root branching and analyze the root meristem and root branching in S. moellendorffii at the microscopical and transcriptional level. Our results show that, in contrast to previous assumptions, initial cells in the root meristem are mostly not tetrahedral but rather show an irregular shape. Tracking down the early stages during root branching argues for the occurrence of a symmetric division of the single initial cell resulting in two apical stem cells allowing for root meristem bifurcation. Moreover, we generated a S. moellendorffii root branching transcriptome, which resulted in the delineation of a subset of core meristem genes. The occurrence of multiple meristem-related orthologues in this dataset, including inversely correlated expression profiles of a SCARECROW (SCR) versus a RETINOBLASTOMA-RELATED1 (RBR1) homologue suggests the presence of conserved pathways in the control of meristem and root stem cell establishment or maintenance.

In vitro mutagenesis in anthurium induced by colchicine

Developing new varieties of anthurium by hybridization can take 8-10 years; therefore, induced mutagenesis can be an alternative strategy to hybridization. The objective of this work was to induce mutations in A. andreanum by exposing explants obtained from vitroplants to colchicine. Explants of leaves, nodes and roots obtained from vitroplants were exposed to 0.1 % colchicine for 0, 2, 3 and 4 h. The mean lethal dose (LD50), survival, number of explants that generated callus, number of explants that formed shoots and the number of shoots per explant were evaluated. The karyotype of the presumed mutated regenerated plants was determined by the root apex squash technique. The leaves showed the highest sensitivity to cochicine. The survival of the root explants treated with colchicine was 100 %; 4 % of roots exposed for 2 and 3 h formed adventitious shoots (120 shoots). For nodes, the LD50 was found at 3.98 h; 76 and 56 % of the nodes cultivated for 2 and 3 h with colchicine formed adventitious shoots (4.4 and 3.6 shoots). The plants regenerated from the explants exposed to colchicine showed morphological changes. The chromosomal number of the regenerated vitroplants from the explants exposed for 2 and 3 h to colchicine was 2n = 29, while that of those obtained from the explants that remained on the colchicine for 4 h was 2n = 31. The sensitivity to colchicine was a function of the type of explant and the dose used. Colchicine caused the loss (monosomy) or gain of chromosomes (trisomy).

Morphological Assessments of Root Apex of Permanent Mandibular First and Second Premolars in a Turkish Population

There is no apical morphological data being available for mandibular first or second premolars in the Turkish population. The aims of the study were (I) to assess apical morphological data of mandibular first and second premolars in a Turkish population at a young-adult age range (II) to analyze potential correlations between the size and position of the apical foramina (AF). Extracted sound teeth were collected from an adult volunteer population as willing to donate. Morphological data were obtained from specimens using a stereomicroscope. The number, size, shape, and position of AF and frequency of accessory foramina were quantified. Mann-Whitney U and Spearman's rank correlation tests were performed (α=0.05). A total of 237 teeth were investigated. The majority of the specimens had one major AF. The frequency of major AF was between 1–3 for both groups. The median AF size in mandibular first and second premolars were 55,180 µm2 and 67,483 µm2, respectively. The majority of foramina shape was irregular for the mandibular first premolars whereas, was oval for the second premolars. The median location of AF with respect to the anatomic apex was 664 µm in mandibular first premolars and 677 µm in mandibular second premolars. The size and location of AF mostly overlap between the mandibular first and second premolars. The shape of the AF might be the only relevant variation concerning the apical morphology between the mandibular first and second premolars in young adults. The interaction between the size and location of AF in mandibular premolars of young adults seems not significant

Structural Features of the Mental Foramen in a Saudi Subpopulation: A Retrospective CBCT Study

Introduction. Accurate and precise knowledge about the position, size, and shape of the mental foramen (MF) are critical in avoiding procedural complications. The MF’s anatomical features vary among different ethnic groups, and various radiographic techniques have been used to determine these variations. Aims. To evaluate the MF’s shape, vertical and horizontal positions, and distance from the border of the mandible. To evaluate the differences among genders as they pertain to the right and left sides of the mandible and research the bilateral symmetry regarding the same variables. Materials and Methods. Cone beam computer tomography (CBCT) scans of 155 Saudi patients (69 males and 86 females) who visited the college of dentistry’s clinics were obtained from the college database for this retrospective study. All the scans were analyzed by 3 calibrated examiners. The data collected was analyzed statistically, and results were obtained. Results. The MF was located under the mandibular second premolar in 56.9% of cases, whereas in 26.9% of cases, it was located between the first and second mandibular premolar. The most prevalent position was below the level of the apices of the mandibular premolar teeth (87.2%). The round shape was most frequent (44.9%) compared to the H-oval (34.7%) and V-oval (20.4%). The V-oval shape was more frequent in males, while the H-oval shape was more frequent in females. The average distance from the center of the MF to the mandibular border was 14.03 ± 1.58 mm , with males exhibiting a greater distance than females. Overall, there were no significant differences between the bilateral symmetry and the right and left sides for all parameters. Conclusion. The most common position of the MF was under the root apex of the mandibular second premolar, with an average distance of about 14 mm from the border of the mandible. The position and shape of the MF were the same bilaterally in the majority of individuals.

Genome-Wide Identification and Gene Expression Analysis of Acyl-Activating Enzymes Superfamily in Tomato (Solanum lycopersicum) Under Aluminum Stress

In response to changing environments, plants regulate gene expression and subsequent metabolism to acclimate and survive. A superfamily of acyl-activating enzymes (AAEs) has been observed in every class of creatures on planet. Some of plant AAE genes have been identified and functionally characterized to be involved in growth, development, biotic, and abiotic stresses via mediating diverse metabolic pathways. However, less information is available about AAEs superfamily in tomato (Solanum lycopersicum), the highest value fruit and vegetable crop globally. In this study, we aimed to identify tomato AAEs superfamily and investigate potential functions with respect to aluminum (Al) stress that represents one of the major factors limiting crop productivity on acid soils worldwide. Fifty-three AAE genes of tomato were identified and named on the basis of phylogenetic relationships between Arabidopsis and tomato. The phylogenetic analysis showed that AAEs could be classified into six clades; however, clade III contains no AAE genes of tomato. Synteny analyses revealed tomato vegetable paralogs and Arabidopsis orthologs. The RNA-seq and quantitative reverse-transcriptase PCR (qRT-PCR) analysis indicated that 9 out of 53 AAEs genes were significantly up- or downregulated by Al stress. Numerous cis-acting elements implicated in biotic and abiotic stresses were detected in the promoter regions of SlAAEs. As the most abundantly expressed gene in root apex and highly induced by Al, there are many potential STOP1 cis-acting elements present in the promoter of SlAAE3-1, and its expression in root apex was specific to Al. Finally, transgenic tobacco lines overexpressing SlAAE3-1 displayed increased tolerance to Al. Altogether, our results pave the way for further studies on the functional characterization of SlAAE genes in tomato with a wish of improvement in tomato crop in the future.

Longitudinal Pattern of Aerenchyma Formation Using the Ti-Gompertz Model in Rice Adventitious Roots

The longitudinal pattern of root aerenchyma formation of its relationship with the function of adventitious roots in rice remains unclear. In this study, the percentage of the aerenchyma area to the cross-sectional area (i.e., aerenchyma percentage) was fit with four non-linear models, namely, W0-Gompertz, Ti-Gompertz, logistic, and von Bertalanffy. Goodness-of-fit criteria such as the R2, the Akaike information criterion (AIC), and the Bayesian information criterion (BIC) were used to select the model. The bias of the parameters was evaluated using the difference between the ordinary least squares-based parameter estimates and the mean of 1,000 bootstrap-based parameter estimates and the symmetry of the distributions of these parameters. The results showed that the Ti-Gompertz model, which had a high goodness-of-fit with an R2 close to 1, lower AIC and BIC values, parameter estimates close to being unbiased, and good linear approximation, provided the best fit for the longitude pattern of rice aerenchyma formation with different root lengths among the competing models. Using the second- and third-order derivatives according to the distance from the root apex, the critical points of Ti-Gompertz were calculated. The rapid stage for aerenchyma formation was from the maximum acceleration point (1.38–1.76 cm from the root apex) to the maximum deceleration point (3.13–4.19 cm from the root apex). In this stage, the aerenchyma percentage increased by 5.3–15.7% per cm, suggesting that the cortical cells tended to die rapidly for the aerenchyma formation rather than for the respiration cost during this stage. Meanwhile, the volume of the aerenchyma of the entire roots could be computed using the integral function of the Ti-Gompertz model. We proposed that the longitudinal pattern of root aerenchyma formation modeled by the Ti-Gompertz model helped to deeply understand the relationship between the anatomical traits and physiological function in rice adventitious roots.

Technical Quality of Endodontic Treatment Performed by Underperforming Undergraduate Dental Students

Objectives: This study aimed to evaluate the technical quality of root canal treatment performed by fifth-year underperforming students, in the extra sessions of the 2018–2019 academic year. Methods: Periapical radiographs of teeth endodontically treated by underperforming undergraduate students at King Abdulaziz University Faculty of Dentistry, were collected. The quality of obturation was evaluated radiographically in relation to the length of obturation to root apex, homogeneity and density of obturation, root canal tapering, and incidence of mishaps (such as perforation, ledge, missed canal, separated instruments). The data were subjected to descriptive analysis. Results: The periapical radiographs of 70 treated teeth showed acceptable length, filling density and root canal taper in 96 (80%),50 (41.7%) and 66 (55%) root canals, respectively. Only four teeth were subjected to mishaps. Conclusion: Under the circumstances of this study, the quality of endodontic treatment performed by underperforming students at the extra session was low. More studies are needed to address the student underperformance source and hence amend the quality of root canal filling.

Reconstructing the childhood diet of individuals buried with the Pictish monastic community at Portmahomack

This research aims to reconstruct the childhood diets (aged 9–10 years) of the individuals buried during the active years of the Pictish monastic community (hereafter referred to as PMC) from early medieval (7th–11th century) Portmahomack in north-east Scotland, using 13C and 15N isotopes. Dietary reconstructions were achieved by isotope analysis of δ13C and δ15N on the tooth root apex from permanent first molars (M1) of 26 adult male individuals. The results indicate that the indi-viduals in PMC predominantly consumed terrestrial C3 resources during childhood, with a rich terrestrial protein diet and some marine resource consumption. Statistically significant differences were observed between childhood and adulthood diets (the latter derived from previous research), suggesting that when these individuals were children, they consumed more marine protein than in later years as adults. This is true for all individuals, whether or not they spent significant time in Portmahomack during their childhoods. This is the most extensive study of the childhood diet of in-dividuals from the PMC and so makes a significant contribution to augmenting information on diet and lifestyles in Pictish Scotland.