Enlarged Root Research Articles

Increasing the Apical Sizes of Root Enlarged for Root Canal Obturation Influences the Outcome of Single-Root-Canal Teeth Affected by Apical Periodontitis.

To investigate the effect of increasing the apical size of roots enlarged for root canal obturation on the outcome of non-surgical endodontic treatment for teeth with apical periodontitis. In this retrospective study, we included 210 cases of single-rooted canals treated at our dental units between October 2009 and January 2022. The clinical outcomes of teeth with enlarged root apical size from the International Organization for Standardization standard numbers 25 to 100 were investigated. The number of teeth with a root apical size of ≤50 and ≥ 55 were 158 and 52, respectively. In the former case, 144 (68.6%) teeth had good prognoses and 14 (6.7%) had poor prognoses. In the latter case, 28 (13.3%) teeth had good prognoses and 24 (11.4%) had poor prognoses. Unfavourable clinical outcomes were observed in root canal-filled teeth with an enlarged apical root size of ≥ 55. Thus, these sizes potentially indicate poor outcomes of nonsurgical endodontic treatments.

The Mechanism of Manganese Ferrite Nanomaterials Promoting Drought Resistance in Rice.

Strategies to reduce the risk of drought damage are urgently needed as intensified climate change threatens agricultural production. One potential strategy was using nanomaterials (NMs) to enhance plant resistance by regulating various physiological and biochemical processes. In the present study, 10 mg kg-1 manganese ferrite (MnFe2O4) NMs had the optimal enhancement to elevate the levels of biomass, photosynthesis, nutrient elements, and polysaccharide in rice by 10.9-525.0%, respectively, under drought stress. The MnFe2O4 NMs were internalized by rice plants, which provided the possibility for rice to better cope with drought. Furthermore, as compared with drought control and equivalent ion control, the introduction of MnFe2O4 NMs into the roots significantly upregulated the drought-sensing gene CLE25 (29.4%) and the receptor gene NCED3 (59.9%). This activation stimulated downstream abscisic acid, proline, malondialdehyde, and wax biosynthesis by 23.3%, 38.9%, 7.2%, and 26.2%, respectively. In addition, 10 mg·kg-1 MnFe2O4 NMs significantly upregulated the relative expressions of OR1, AUX2, AUX3, PIN1a, and PIN2, and increased IAA content significantly, resulting in an enlarged root angle and a deeper and denser root to help the plant withstand drought stresses. The nutritional quality of rice grains was also improved. Our study provides crucial insight for developing nano-enabled strategies to improve crop productivity and resilience to climate change.

Adapting rice to rising atmospheric carbon dioxide: A preliminary GMO approach to maintain nutritional integrity

Although there is extensive evidence that rising atmospheric carbon dioxide concentration, [CO2] can stimulate rice yields, such increases are also associated with a ubiquitous decline in nutrition, including protein, iron (Fe) and zinc (Zn). To determine the basis for these declines, we used gmo rice line pairs to test and compare the quantitative and qualitative metrics relative to their non-gmo counterparts at elevated [CO2] in situ. The gmo / non-gmo paired comparisons were associated with two phenological / metabolic characteristics associated with nutritional integrity: (1) an enlarged root system and (2) enhanced nitrate absorption. The two gmo lines showed a significantly higher percent stimulation of seed yield relative to their paired non-gmo cultivar at elevated [CO2]. However, relative to their non-gmo counterparts, leaf nitrogen and brown rice protein were not significantly reduced. In addition, the enlarged root system gmo line showed no decline in Fe and Zn at elevated [CO2]. While these findings are preliminary, they provide insight into specific traits associated with [CO2] induced declines in nutrition and could be fundamental in selecting and breeding qualitative and quantitative responses of global rice to maintain yield increases and nutritional integrity in response to projected increases in atmospheric [CO2].

Retention of Manually or CAD/CAM-customized Fiberglass Posts Luted to Enlarged Root Canals with Different Resin Cements.

The aim of this laboratory study was to evaluate the pull-out force of a prefabricated fiberglass post (PP), relined fiberglass post (RP), or milled fiberglass post (MP) luted with Multilink N (MN), RelyX Unicem 2 (RXU2) or RelyX Ultimate (RU) to enlarged root canals. The thickness of the resin cements and the presence of voids in the resin cement film were observed. The root canals of 90 bovine incisors were enlarged, endodontically treated, and randomly divided into 9 groups (n=10) according to the post type and resin cement. The specimens were scanned using micro-CT to analyze the thickness of the resin cement and the presence of voids. The specimens were submitted to mechanical cyclic loading (500,000 cycles at 50 N load) and subjected to pull-out force testing. Two-way ANOVA and Tukey's test analyzed the pull-out force and resin cement thickness data. Kruskal-Wallis and Bonferroni tests analyzed the void scores. The interaction between factors (post × resin cement) was significant (p=0.0001) for the pull-out force. Higher pull-out forces were obtained for RP and MP compared to PP. The post factor was significant (p=0.0001) for resin cement thickness, which was higher for PP (1054 μm), followed by MP (301 μm) and RP (194 μm). More void formation occurred for PP, being less for RP, differing significantly among the posts. Post customization (RP and MP) decreased resin cement thickness and void formation, favoring a higher pull-out force. Resin cements requiring an adhesive application (MN and RU) favored higher pull-out force than self-adhesive resin cement (RXU2).

Down-regulation of GhADF1 in cotton (Gossypium hirsutum) improves plant drought tolerance and increases fiber yield

Fiber productivity and quality of cotton are severely affected by abiotic stresses. In this study, we identified the role of GhADF1, an actin depolymerizing factor, in cotton response to drought stress. GhADF1 expression in cotton could be induced by PEG6000. GhADF1-RNAi transgenic cotton showed increased tolerance to drought stress during seed germination and seedling development as well as at the reproductive stage. In contrast, overexpression of GhADF1 led to a drought-sensitive phenotype in transgenic plants. GhADF1-RNAi plants produced an enlarged root system with longer primary roots, more lateral roots, increased root dry biomass, and increased cell size. In leaves of GhADF1-RNAi cotton, proline content and activities of reactive oxygen species-scavenging enzymes were increased following drought stress compared with those in wild type. GhADF1-RNAi lines showed higher water-use efficiency than the wild type, accompanied by reduced leaf stomatal density and conductance. GhADF1-RNAi cotton produced higher fiber yield in the field under both normal and drought conditions. Transcriptomic analyses identified 124 differentially expressed genes in leaves of GhADF1-RNAi lines compared with the wild type following drought treatment. Upregulated genes included those encoding transcription factors, protein kinases, heat shock proteins, and other proteins known to be involved in stress responses. We conclude that GhADF1 reduces the expression of abiotic stress-associated genes in cotton response to drought stress and may be a promising candidate gene for crop improvement by genetic manipulation.

"Roof" technique-a modified aortotomy closure in Y-incision aortic root enlargement upsizing 3-4 valve sizes.

"Roof" technique-a modified aortotomy closure in Y-incision aortic root enlargement upsizing 3-4 valve sizes.

Petrophysics and sediment variability in a mixed alluvial to lacustrine carbonate system (Miocene, Madrid Basin, Central Spain)

AbstractThis study evaluates variations in petrophysical properties within a mixed alluvial to lacustrine carbonate system (Miocene, Madrid Basin, Central Spain). The transition from alluvial environments to lake margins settings displays a shift from alluvial, siliciclastic red sandstones and mudstones to palustrine–lacustrine mudstones to packstones. Fluctuations in lake‐water level enabled land plants to occupy the lake margins during periods of low lake levels. The palustrine carbonates include features like pseudo‐microkarst, nodular and mottled limestones; the lacustrine deposits include enlarged root cavities, desiccation cracks and channel bodies. Scarce fresh water biota comprises charophytes, gastropods and ostracods. The sediments possess high natural, irregular varying, gamma‐ray values at the alluvial–lacustrine transition, and low, but constant values at full lacustrine sites. Acoustic properties agree with lithological variations within individual facies. Porosity is the most important parameter influencing P‐wave and S‐wave velocities. The scatter in the velocity–porosity relationship links to the porosity type; macro‐porosity or microporosity. The wide range of pore types and pore sizes results in a weak porosity to permeability relationship for the carbonate‐dominated rocks with low permeability for microporous and high permeability for macro‐porous carbonates. The sandstones (probably only inhibiting interparticle porosity), and to a lesser extent the sandy wackestones to packstones, show quite a strong relationship between porosity and permeability. Elastic properties of mixed alluvial–lacustrine deposits (this study) and marine deposits (literature data) overlap as variations in pore structures and porosity values are similar. Only 16% of the marine and lacustrine carbonate sediments display Equivalent Pore Aspect Ratio values above 0.2. In travertine deposits, 83% of the samples exceed Equivalent Pore Aspect Ratio values above 0.2, which highlights that travertine deposits are dominated by larger Equivalent Pore Aspect Ratios compared to lacustrine and marine carbonate deposits. Travertines display other rock frameworks with different pore types, pore distribution and amount of porosity.

Predictive scoring model for inferior alveolar nerve injury after lower third molar removal based on features of cone-beam computed tomography image

IntroductionThis study aimed to construct a predictive scoring system for inferior alveolar nerve injury (IANI) following lower third molar (LM3) surgery based on cone-beam computed tomography (CBCT) images. Material and MethodsOf the 1573 patients who underwent LM3 removal following the CBCT, 39 with IANI and 457 randomly selected patients without IANI were enrolled. We collected information regarding the demographic characteristics of the patients, surgical situations, and inferior alveolar canal (IAC)-related CBCT factors. The association with IANI-risk was evaluated with a backward stepwise logistic regression model as per the Akaike information criterion. Scoring models’ abilities of discrimination (area under the curve) and calibration (Hosmer–Lemeshow test and calibration plots) were assessed, followed by evaluation of the clinical usefulness using decision curve analysis. ResultsAs per the multivariate analysis, the coronal positioned IAC on the enlarged root (odds ratio [OR], 3.78; P = 0.001), the length of perforated IAC (>3.4 mm) (OR, 3.05; P = 0.012), lingual/inter-radicular position of the IAC (OR, 3.96; P = 0.001), multiple roots closed to the perforated IAC (OR, 2.78; P = 0.025), and age >30 y (OR, 2.31; P = 0.076) were identified in the extended scoring model ranging from 0 to 12. This model was compared with our previously constructed baseline model that involved the latter three variables mentioned above, resulting in superior performance than that of the baseline model. ConclusionThe extended model would be a useful tool for reliable determination of the preoperative probability of IANI.

MYB3R-mediated active repression of cell cycle and growth under salt stress in Arabidopsis thaliana.

Under environmental stress, plants are believed to actively repress their growth to save resource and alter its allocation to acquire tolerance against the stress. Although a lot of studies have uncovered precise mechanisms for responding to stress and acquiring tolerance, the mechanisms for regulating growth repression under stress are not as well understood. It is especially unclear which particular genes related to cell cycle control are involved in active growth repression. Here, we showed that decreased growth in plants exposed to moderate salt stress is mediated by MYB3R transcription factors that have been known to positively and negatively regulate the transcription of G2/M-specific genes. Our genome-wide gene expression analysis revealed occurrences of general downregulation of G2/M-specific genes in Arabidopsis under salt stress. Importantly, this downregulation is significantly and universally mitigated by the loss of MYB3R repressors by mutations. Accordingly, the growth performance of Arabidopsis plants under salt stress is significantly recovered in mutants lacking MYB3R repressors. This growth recovery involves improved cell proliferation that is possibly due to prolonging and accelerating cell proliferation, which were partly suggested by enlarged root meristem and increased number of cells positive for CYCB1;1-GUS. Our ploidy analysis further suggested that cell cycle progression at the G2 phase was delayed under salt stress, and this delay was recovered by loss of MYB3R repressors. Under salt stress, the changes in expression of MYB3R activators and repressors at both the mRNA and protein levels were not significant. This observation suggests novel mechanisms underlying MYB3R-mediated growth repression under salt stress that are different from the mechanisms operating under other stress conditions such as DNA damage and high temperature.

Effects of root radius and pitch difference on fatigue strength and anti-loosening performance for high strength bolt–nut connections

The fatigue strength improvement and anti-loosening performance are studied experimentally and analytically for JIS M16 bolt–nut connections. Three different root radii are considered coupled with three different pitch differences. The enlarging the bolt root radius improves the fatigue limit of the bolt by more than 30% because both stress amplitude and mean stress can be reduced. Furthermore, suitable pitch difference improves the fatigue limit by more than 25%. This is because under no pitch difference the crack initiation always occurs at No.1 or No.2 threads close to the bolt head causing the final failure; however, under a suitable pitch difference the crack initiation occurs at No.6 or No.7 threads far away from the bolt head. Good anti-loosening performance can be expected for the bolt–nut connections having enlarged root radius because the prevailing torque [Formula: see text] = 19 Nm and the residual prevailing torque [Formula: see text] are not smaller compared to other special bolt–nut connections.

A novel simple technique to enlarge the aortic annulus by two valve sizes.

A novel simple technique to enlarge the aortic annulus by two valve sizes.

Cell Dynamics in WOX5-Overexpressing Root Tips: The Impact of Local Auxin Biosynthesis.

Root stem cell niche functioning requires the formation and maintenance of the specific “auxin-rich domain” governed by directional auxin transport and local auxin production. Auxin maximum co-localizes with the WOX5 expression domain in the quiescent center that separates mitotically active proximal and distal root meristems. Here we unravel the interconnected processes happening under WOX5 overexpression by combining in vivo experiments and mathematical modeling. We showed that WOX5-induced TAA1-mediated auxin biosynthesis is the cause, whereas auxin accumulation, PIN transporters relocation, and auxin redistribution between proximal and distal root meristems are its subsequent effects that influence the formation of the well-described phenotype with an enlarged root cap. These findings helped us to clarify the role of WOX5, which serves as a local QC-specific regulator that activates biosynthesis of non-cell-autonomous signal auxin to regulate the distal meristem functioning. The mathematical model with WOX5-mediated auxin biosynthesis and auxin-regulated cell growth, division, and detachment reproduces the columella cells dynamics in both wild type and under WOX5 dysregulation.

The HK5 and HK6 cytokinin receptors mediate diverse developmental pathways in rice.

The phytohormone cytokinin regulates diverse aspects of plant growth and development. Our understanding of the metabolism and perception of cytokinin has made great strides in recent years, mostly from studies of the model dicot Arabidopsis Here, we employed a CRISPR/Cas9-based approach to disrupt a subset of cytokinin histidine kinase (HK) receptors in rice (Oryza sativa) in order to explore the role of cytokinin in a monocot species. In hk5 and hk6 single mutants, the root growth, leaf width, inflorescence architecture and/or floral development were affected. The double hk5 hk6 mutant showed more substantial defects, including severely reduced root and shoot growth, a smaller shoot apical meristem, and an enlarged root cap. Flowering was delayed in the hk5 hk6 mutant and the panicle was significantly reduced in size and infertile due to multiple defects in floral development. The hk5 hk6 mutant also exhibited a severely reduced cytokinin response, consistent with the developmental phenotypes arising from a defect in cytokinin signaling. These results indicate that HK5 and HK6 act as cytokinin receptors, with overlapping functions to regulate diverse aspects of rice growth and development.

The Medicago truncatula nodule identity gene MtNOOT1 is required for coordinated apical-basal development of the root

BackgroundLegumes can utilize atmospheric nitrogen by hosting nitrogen-fixing bacteria in special lateral root organs, called nodules. Legume nodules have a unique ontology, despite similarities in the gene networks controlling nodule and lateral root development. It has been shown that Medicago truncatula NODULE ROOT1 (MtNOOT1) is required for the maintenance of nodule identity, preventing the conversion to lateral root development. MtNOOT1 and its orthologs in other plant species -collectively called the NOOT-BOP-COCH-LIKE (NBCL) family- specify boundary formation in various aerial organs. However, MtNOOT1 is not only expressed in nodules and aerial organs, but also in developing roots, where its function remains elusive.ResultsWe show that Mtnoot1 mutant seedlings display accelerated root elongation due to an enlarged root apical meristem. Also, Mtnoot1 mutant roots are thinner than wild-type and are delayed in xylem cell differentiation. We provide molecular evidence that the affected spatial development of Mtnoot1 mutant roots correlates with delayed induction of genes involved in xylem cell differentiation. This coincides with a basipetal shift of the root zone that is susceptible to rhizobium-secreted symbiotic signal molecules.ConclusionsOur data show that MtNOOT1 regulates the size of the root apical meristem and vascular differentiation. Our data demonstrate that MtNOOT1 not only functions as a homeotic gene in nodule development but also coordinates the spatial development of the root.

Overexpression of the Cytokinin Oxidase/dehydrogenase (CKX) from Medicago sativa Enhanced Salt Stress Tolerance of Arabidopsis

Cytokinin oxidase/dehydrogenase (CKXs) are involved in various physiological processes, including cytokinins (CKs) catabolism, root system architecture and response to abiotic stresses in plants. Alfalfa (Medicago sativa) is a widely cultivated forage which is frequently threatened by high salinity, and the potential role of CKXs in alleviating the salt stress in alfalfa lacked attention. In this study, we isolated a CKX gene from alfalfa, MsCKX (MK177192), and identified its biological functions by overexpressing it in Arabidopsis. MsCKX shares high sequence identity with CKX from other legume plants, especially Medicago truncatula (98%). MsCKX was clearly tissue-specific, and it was mainly expressed in roots. In addition, the expression of MsCKX increased under salt stress and abscisic acid (ABA) treatment. Overexpression of MsCKX gene increased the activity of CKX, which led to an enlarged root system in transgenic Arabidopsis plants. Overexpression of MsCKX gene enhanced salt tolerance of transgenic plants by maintaining a higher K+/Na+ ratio, enhancing the activities of antioxidant enzymes to scavenge ROS and increasing the expression levels of stress-related genes (P5CS1, DREB2, ion transporters and H+ pumps). Taken together, these results shed light on the roles of MsCKX involved in salt tolerance and may have applications in salt-resistant breeding of alfalfa.

Evaluating the risk of post-extraction inferior alveolar nerve injury through the relative position of the lower third molar root and inferior alveolar canal

The aim of this study was to introduce a method to evaluate the risk of inferior alveolar nerve (IAN) injury following the extraction of impacted lower third molars. Two hundred impacted lower third molars adjacent to the IAN were evaluated. These were divided into four classification groups according to preoperative cone beam computed tomography (CBCT) findings: AR, apical region; LT, lateral region of the tapered root; LE, lateral region of the enlarged root; AE, adjacent to the enlarged root. All teeth were dislocated along the long axis or arc of the root by tooth sectioning technique and extracted by a single surgeon. The primary outcome variable was postoperative neurosensory impairment of the IAN. The χ2 test was used to evaluate differences in postoperative IAN injury between the classifications. Logistic regression analysis was used to evaluate the risk factors for postoperative IAN injury. The overall incidence of postoperative IAN injury was 7%. Specifically, most injuries involved classification AE (AE 36%, LE 8.6%, LT 3.6%, AR 0%), and the difference was statistically significant (P< 0.05). Logistic regression showed that classification AE was the only risk factor for postoperative IAN injury (P< 0.001). According to preoperative CBCT, the risk of postoperative IAN injury is higher when the IAN is adjacent to the enlarged part of the root.

Release of Transforming Growth Factor Beta 1 from Human Tooth Dentin after Application of Either ProRoot MTA or Biodentine as a Coronal Barrier

IntroductionVarious factors may influence intracanal calcification in teeth treated with regenerative endodontic procedures. Bioactive materials, including ProRoot MTA (MTA; Dentsply Tulsa Dental Specialties, Memphis, TN) and Biodentine (BD; Septodont, Saint-Maur-des-Fossés, France), have been widely used as a coronal barrier in the final step of regenerative endodontic procedures. The purposes of this study were to evaluate the effect of either MTA or BD after application as a coronal barrier on transforming growth factor beta 1 (TGF-β1) release from root canal dentin and to observe the impact of these materials on human apical papilla cell (APC) mineralization. MethodsEither MTA or BD was applied in enlarged root canals of human root segments. After storing for 14 days in phosphate-buffered saline, TGF-β1 release was evaluated using an enzyme-linked immunosorbent assay. To investigate the effect of the materials on APC mineralization, APCs were grown in the presence of either the materials alone or material-filled root segments. Cell mineralization was quantified after 14 and 21 days using alizarin red S staining. Calcium deposits were quantitatively analyzed. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U tests with the significance level at .05. ResultsThe greatest amount of TGF-β1 release was observed in the root segments treated with BD. BD, used either alone or as a coronal barrier, promoted greater APC mineralization than did MTA on both days 14 and 21. Interestingly, when BD was applied as a coronal barrier, the mineralization effect was significantly reduced compared with the use of the materials alone (P < .05). ConclusionsWhen used as a coronal barrier, BD promoted the release of TGF-β1 from the root canal dentin. A higher mineralization effect was observed with BD than with MTA.

Relationship between Canal Enlargement and Fracture Load of Root Dentin Sections

ObjectiveTo investigate the effect of endodontic instrumentation on fracture susceptibility of rootdentin using experiments and stress analysis. MethodsRoot canals of lower premolars were enlarged with different tapers. After, teeth were cut into 2-mm sections. A metal rod of the same taper was pushed through the center of the sections using a universal test system to fracture them. The fracture load was determined from the peak load on the load-displacement curve. To determine fracture-causing stress, an axisymmetric FE model was created. An analytical solution was developed to understand the relationship between fracture load, geometrical and material parameters. ResultsFor the same taper, increased root canal diameter did not lead to reduced fracture load. Both analytical and FE solutions showed positive linear relationship between fracture load and enlarged root canal diameter. The hoop stress was maximum at inner surface of enlarged root canal and reduced with increasing radial distance from the center. Bending of sections introduced further nonuniform stresses along the depth. Predictions for the fracture load based on the maximum hoop stress were closest to experimental values; however, account must be taken of the variation in fracture stress of dentin along the root length.Significance Our results rejected the hypothesis that fracture load of root dentin sections reduced with endodontic instrumentation size. However, the stress distributions in whole endodontically treated teeth are more complicated. Thus, caution is necessary when using thin root sections to investigate the effect of endodontic instruments on vertical root fracture.

Maximizing seedling and root tuber production in Polygonum multiflorum for use in ethnomedicine

There is need for a robust production mechanisms to meet the ever increasing demand for herbal medicine in the world today. In this study, we developed a standard protocol for the in vitro culture of Polygonum multiflorum to rapidly produce seedlings and promote the enlargement of its medicinal root tubers. Seeds were grown on Murashige and Skoog (MS) basal medium to obtain 1-week-old microseedlings. The ideal growth medium for these seedlings was determined by subculturing in different culture media. Maximal growth was observed on WPM, with a growth index of 160% after 5 weeks. Wood Plant Medium (WPM) supplemented with the kinetin and indole-3-acetic acid hormones yielded the highest average seedling shoot elongation, root initiation, and root elongation after 6 weeks. At 16 weeks after planting in the field, seedlings cultured in WPM + kinetin (1.0 mg/l) and IAA (1.0 mg/l) produced enlarged root tubers with an average dry weight of 31.10 g, as compared to 10.10 and 16.80 g for root tubers from plants propagated from P. multiflorum seed and stem cuttings, respectively. Fourier-transform infrared spectroscopy and hierarchical cluster analyses of the enlarged root tubers revealed that their chemical composition was the same as that of tubers sold on the market and from plants propagated through seeds and stem cuttings. Our findings provide a basis for large-scale in vitro propagation of P. multiflorum as a resource for traditional Chinese medicine.

Root Engineering in Barley: Increasing Cytokinin Degradation Produces a Larger Root System, Mineral Enrichment in the Shoot and Improved Drought Tolerance

Root size and architecture are important crop plant traits, as they determine access to water and soil nutrients. The plant hormone cytokinin is a negative regulator of root growth and branching. Here, we generated transgenic barley (Hordeum vulgare) plants with an enlarged root system by enhancing cytokinin degradation in roots to explore the potential of cytokinin modulations in improving root functions. This was achieved through root-specific expression of a CYTOKININ OXIDASE/DEHYDROGENASE gene. Enhanced biomass allocation to roots did not penalize shoot growth or seed yield, indicating that these plants were not source limited. In leaves of transgenic lines, the concentrations of several macroelements and microelements were increased, particularly those with low soil mobility (phosphorus, manganese, and zinc). Importantly, seeds contained up to 44% more zinc, which is beneficial for human nutrition. Transgenic lines also demonstrated dampened stress responses to long-term drought conditions, indicating lower drought sensitivity. Taken together, this work demonstrates that root engineering of cereals is a promising strategy to improve nutrient efficiency, biofortification, and drought tolerance.