Apical Sections Research Articles

1097 PROGNOSTIC IMPACT OF HISTOPATHOLOGIC CHARACTERISTICS OF POSITIVE APICAL MARGINS IN PATIENTS WITH CLINICALLY LOCALIZED PROSTATE CANCER

You have accessJournal of UrologyProstate Cancer: Localized1 Apr 20111097 PROGNOSTIC IMPACT OF HISTOPATHOLOGIC CHARACTERISTICS OF POSITIVE APICAL MARGINS IN PATIENTS WITH CLINICALLY LOCALIZED PROSTATE CANCER Ryan Dorin, Peter Nichols, Jie Cai, Donald Skinner, and Gary Lieskovsky Ryan DorinRyan Dorin Los Angeles, CA More articles by this author , Peter NicholsPeter Nichols Los Angeles, CA More articles by this author , Jie CaiJie Cai Los Angeles, CA More articles by this author , Donald SkinnerDonald Skinner Los Angeles, CA More articles by this author , and Gary LieskovskyGary Lieskovsky Los Angeles, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.2600AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Previous studies on radical prostatectomy (RP) patients have reported that the length of a positive surgical margin may be predictive of disease recurrence, but it is unknown if this finding is applicable to patients with a positive apical margin (AM+) only. We analyzed the impact on outcomes of several specific histopathologic characteristics of AM+ specimens in patients with clinically localized (cT1 / cT2) prostate cancer who underwent RP, with the aim of improving risk stratification for this patient population. METHODS Utilizing an IRB approved prospectively maintained database, we identified 1663 patients with clinically localized prostate cancer who underwent RP between 1988 and 2003 at our institution. There were 188 patients with an apical-only positive surgical margin, of whom 174 had apical margin (AM) sections available for detailed microscopic re-examination by a single urologic pathologist. Histopathologic characteristics of the AM sections were measured and recorded, including length and estimated area of margin involvement, primary Gleason grade of tumor at the margin, and the extent of tumor in the apical section. The risk of disease recurrence (biochemical or clinical) was calculated for each variable using a log rank test, and multivariate analyses were conducted to control for adjuvant radiation, pathologic tumor stage and Gleason grade. RESULTS Median follow up was 10.2 years and the estimated 10 year biochemical recurrence (BCR) free survival was 85%. AM tissue was sectioned using the “shave” technique in 151 specimens, and using the “cone” technique in 23 specimens. On univariate and multivariate analyses, primary Gleason grade at the AM (hazard ratio (HR)=1.7 for Gleason 4 vs. 3, HR=7.3 for Gleason 5 vs. 4, p= 0.018), and the area of tumor in contact with the AM (HR=12.4 for >27mm2, p<0.001) were significant predictors of BCR. In patients who did not receive adjuvant radiation (N=85), percent of the AM involved by tumor was also predictive of disease recurrence (HR=5.2 for >15%, p=0.024). However, length of the AM in contact with tumor was not predictive of recurrence on univariate or multivariate analyses. CONCLUSIONS In patients with clinically organ confined prostate cancer undergoing RP who have an isolated positive AM, the primary Gleason grade and area of tumor in contact with the margin may be useful in identifying patients at a higher risk of recurrence. The length of an isolated positive AM does not appear to be a significant predictive factor for disease progression. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e441 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ryan Dorin Los Angeles, CA More articles by this author Peter Nichols Los Angeles, CA More articles by this author Jie Cai Los Angeles, CA More articles by this author Donald Skinner Los Angeles, CA More articles by this author Gary Lieskovsky Los Angeles, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

The effect of post surface silanization and luting agents on the push-out bond strengths of adhesively inserted fiber reinforced posts

The effect of silane treatment on the push-out bond strengths of three different luting agents to fiber-reinforced composite (FRC) posts after thermocycling was evaluated. Sixty single-rooted human maxillary central incisors were sectioned below the cemento–enamel junction, and the roots were endodontically treated. RelyX Fiber Posts (size #2) were inserted using etch-and-rinse, self-etch, and self-adhesive luting agents (cementing agents). For half of the specimen in each group, the fiber posts were treated with a silane coupling agent. Bonded specimens were cut (2-mm-thick sections) and push-out tests were performed (crosshead speed, 0.5 mm/min). Failure modes were evaluated using a stereomicroscope at original magnification ×40. For each luting agent the use of silane did not result in any statistically significant difference at any level of the root compared to those of the control groups except for Variolink II and RelyX Unicem luting agents in apical root section ( p<0.05; one-way ANOVA). The post hoc analysis showed that regardless of the pre-treatment procedures, Variolink II achieved significantly higher bond strengths than Panavia F 2.0 and RelyX Unicem in all root sections ( p<0.05). The use of a silane coupling agent had no influence on bond strengths depending on the luting agent used, whereas the type of luting agent (etch-and-rinse, self-etch, and self-adhesive) appeared to be a significant influence on the push-out bond strength values independent of the pre-treatment used. Therefore, pre-treatment of fiber posts with a silane coupling agent does not seem to be mandatory, which saves time in the clinical situation.

Bacterial localization and viability assessment in human ex vivo dentinal tubules by fluorescence confocal laser scanning microscopy

To develop a convenient method for the localization and quantification of live and dead bacteria in human ex vivo mineralized dentinal tubules. The roots from human single-rooted teeth (n = 12) were infected with Enterococcus faecalis V583 and either treated with calcium hydroxide paste or left untreated; six control roots were uninoculated and untreated. Following further incubation, roots were stained with fluorescent DNA-binding reagents, washed thoroughly, sectioned and examined by confocal laser scanning microscopy. Computer-assisted determinations of fluorescence (bacterial viability) were compared statistically. Bacteria were distributed in the tubules throughout the length of the roots but tubule penetration distance was slightly reduced in the apical sections. There was no significant difference in bacterial tubule penetration between roots from different teeth and small standard deviations indicated reproducibility appropriate for experimental application. Following treatment with calcium hydroxide paste, live and dead bacteria were readily distinguishable by contrasting green and red fluorescence. Bacterial viability determinations amongst roots treated in the same way were not significantly different, and the small standard deviation is commensurate with experimental application. Fluorescent viability staining is a convenient, accurate and reproducible method for localizing and quantifying live and dead bacteria in human ex vivo mineralized dentinal tubules.

Effects of chitosan on dental bone repair

Objectives: Bone defects following tumor resection and osteolysis due to dental and bone lesions and periodentium tissue disorders are serious challenges. One of these materials used is chitosan, a derivative of crustaceans’ exoskeleton. The aim of this study was to assess effects of chitosan on socket repair after dental extraction. Methods: Twenty four dental sockets of 15-24 years old patients were visited by a maxillofacial surgeon for extracting premolar teeth for orthodontic purposes. The sockets in one side were filled-in by chitosan. In the other side, the sockets were left unfilled. After 10 weeks, periapical radiographs were obtained from the repair sites, were digitalized and then evaluated for densitometry using Adobe Photoshop Software. Each socket was divided into coronal, middle and apical. Dental density of each socket in case and control groups was recorded. The density of regenerated bone was compared against the maximum bone density of each individual. Wilcoxon signed range test and paired t-test were used for data analysis. Results: Bone density in middle and apical sections in case group was significantly more than control group. In apical section in case group regenerated bone reached up to 98.2% of normal bone density. In each patient, the bone density in epical and middle sections was increase 29.3% and 10.8% of normal bone density. Conclusions: Chitosan significantly increased bone density in epical and middle sections. Chitosan can be used for bone repair in cases of bone loss. Various densitometry studies for evaluating chitosan effects in different bone defects are suggested.

The Effect of a Hyperdynamic Circulation on Tissue Doppler Values: A Simulation in Young Adults during Exercise

Left ventricular tissue Doppler imaging (TDI) velocities are used to monitor systolic and diastolic function, but it is not known how these may change in a hyperdynamic circulation, as often occurs in anesthesia and critical care medicine. Twenty-six healthy young volunteers were recruited and left ventricular systolic and diastolic tissue Doppler velocities measured at rest, light exercise, strenuous exercise, and recovery (10 minutes after exercise). At rest, TDI velocities significantly decreased from base to apex (P < .001). Within basal, mid, and apical sections, systolic and diastolic peak velocities differed between segments (P < .05), except for systolic middle (P = .094) and late diastolic apical velocities (P = .257). Basal septal velocities differed from basal lateral, for systolic (P = .041) but not diastolic peak values. Inferobasal radial values differed from basal lateral values for both systolic and diastolic velocities (P < .05). Both systolic and diastolic TDI velocities increased significantly in all segments in a proportionate manner with a hyperdynamic circulation.

CHANGES IN SUGAR AND TOTAL OXALIC ACID CONTENTS IN DIFFERENT SECTIONS OF BAMBOO SHOOTS HARVESTED AT DIFFERENT MATURITY

ISHS International Symposium Postharvest Pacifica 2009 - Pathways to Quality: V International Symposium on Managing Quality in Chains + Australasian Postharvest Horticultural Conference CHANGES IN SUGAR AND TOTAL OXALIC ACID CONTENTS IN DIFFERENT SECTIONS OF BAMBOO SHOOTS HARVESTED AT DIFFERENT MATURITY

Micro push-out bond strengths of 2 fiber post types luted using different adhesive strategies

The objective of this study was to evaluate the push-out bond strengths of carbon and glass fiber posts adhesively luted with Panavia F 2.0 and RelyX Unicem luting cements, as well as a modified application procedure using RelyX Unicem cement in combination with a single-bottle total-etch adhesive in 3 segments of teeth. Sixty single-rooted human maxillary central incisors and canines were sectioned below the cementoenamel junction, and the roots were endodontically treated. The roots were divided into 2 fiber-post groups, and then divided into 3 subgroups of 10 specimens each to test different luting strategies. Bonded specimens were cut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Failure modes were evaluated using a stereomicroscope at original magnification ×40. Micro push-out bond strengths were significantly affected by the type of luting agent and the type of post (P < .05). In all root sections, the push-out bond strength values of glass fiber posts were significantly higher than that of carbon fiber posts (P < .05). Moreover, the highest push-out bond strengths were measured for Panavia F 2.0 and RelyX Unicem cements. These values were significantly higher than that of modified application procedure in the medium section for both glass- and carbon-fiber posts, and in the apical root sections only for glass-fiber post (P < .05). In each region, the modified application procedure showed the lowest bond strength values. Adhesive failure between dentin and cement was the most frequent type of failure. In all root segments, the glass fiber post provided significantly increased post retention compared with the carbon fiber post, regardless of the luting strategy used.

Resistance and response of Pinus pinaster seedlings to Hylobius abietis after induction with methyl jasmonate

Experimental induction of plant chemical defences with methyl jasmonate (MeJa) is a valuable tool for understanding the ecology of plant defensive responses. However, few studies have examined whether MeJa-induced defences in conifers are effective against insect herbivores. We studied, in 17 half-sib Pinus pinaster families, (i) the effect of MeJa application on plant growth and on the induction of diterpenoid resin in different sections of the stem; (ii) whether MeJa-induced defences increase the resistance of living pine juveniles against the large pine weevil Hylobius abietis in an in vivo bioassay and (iii) the induction of resin content after weevil wounding. Resin concentration was greater in the upper section of the stem compared with basal sections in both MeJa-induced and non-induced seedlings. Sixty days after MeJa application, treated plants showed 40% greater resin content all along the stem, but reduced height growth compared to control plants. MeJa-induction was effective against the pine weevil, as induced seedlings were 21% less damaged than control plants. Wounding activity by H. abietis produced a strong local defensive response after 48 h, where resin concentration was double that observed in the basal and apical sections not exposed to the insects.

Effect of F‐File on removal of the smear layer: A scanning electron microscope study

The aim of this study was to evaluate the effectiveness of F-File with NaOCl on removal of the smear layer. A total of 48 single-rooted teeth were instrumented using crown-down technique with one of the irrigation agents: distilled water, 5.25% NaOCl, RC-Prep, Glyde, MTAD or F-File with NaOCl. The remaining smear layer was scored at cervical, middle and apical thirds of the roots with SEM. In all the canals of experimental groups the coronal sections were cleaner than the middle and apical sections except with distilled water (P<0.001). In the coronal third, intensive smear layer was observed in distilled water, NaOCl and F-File groups and less smear layer in MTAD (P<0.05) and least in RC-Prep and Glyde groups. In the middle third, RC-Prep and Glyde groups had less smear layer than the other groups (P<0.001). In the apical third, there was intensive smear layer in all specimens and statistical analyses showed no significant difference among the groups (P>0.05). The F-file failed to improve the effect of NaOCl in removing smear layer.

Comparison of dentine removal using V‐taper and K‐Flexofile instruments

To compare the dentine removal ability of V-Taper and K-Flexofile instruments in mesiobuccal canals of extracted mandibular first molar teeth. Preoperative images of 40 mesiobuccal canals of mandibular first molars (with a curvature between 20° and 35°) were obtained at 2, 4.5, and 7 mm from the root apices by CT-scan and divided into two groups. Group F was prepared with K-Flexofiles and Gates Glidden drills and Group V with V-Taper Ni-Ti rotary and stainless steel hand instruments. Post-instrumentation images were then obtained and compared with the preoperative images. The ratio of dentine removal based on pre- and postoperative images was calculated, and data was analysed by anova and Tukey post hoc test. In group F in the coronal sections, the least ratio of the dentine removal to the initial root thickness was on the buccal aspect (15.14% ± 6.72), and the greatest ratio was found on the distolingual (29.38% ± 8.19). In group V in the coronal, the least ratio of the dentine removal to the initial root thickness was on the buccal aspect (9.81% ± 3.26); the greatest ratio was found on the distolingual surface in the coronal sections (34.38% ± 10.51). In the middle sections, the least ratio was on the buccal (10.51% ± 3.39) and the greatest on the distolingual aspects (27.46% ± 12.34) of the roots. In the apical sections, the amount of the dentine removed from the mesial and distal surfaces in group V was significantly more than group F (P < 0.01). The distolingual aspect of the root canal is a danger zone for the mesiobuccal canal of the mesial root in mandibular molar teeth, and preparation of that area should be performed with caution. Except the apical part of the canal, no significant difference was found between the two preparation files or techniques used. Apart from the apical part of the canal, neither instrument maintained the original shape of the coronal and middle parts of the canal.

In vitro regeneration of Lycaste aromatica (Graham ex Hook) Lindl. (Orchidaceae) from pseudobulb sections

A protocol for in vitro propagation from pseudobulb sections of Lycaste armomatica (Graham ex Hook) Lindl., an ornamental and fragrant orchid, was developed. The effect of four cytokinins: kinetin (K), meta-topolin (mT), N 6-benzyladenine (BA), and thidiazuron (TDZ), in equimolar concentrations, was investigated. Shoot formation from apical and basal pseudobulb sections was obtained in all treatments. A few medial sections cultured in media supplemented with BA formed protocorm-like bodies. Shoot formation was greater from the basal section than the apical, and mainly occurred in explants cultured in media containing TDZ. The highest average numbers of shoots per explant were achieved from basal sections cultured in media supplemented with TDZ at 4.4, 8.87 and 2.2 µM, forming on average 9.9, 8.6 and 7.3 shoots per explant, respectively. Since the medial pseudobulb section was the worst explant for propagation of L. aromatica, we recommend that pseudobulbs be divided into two sections; the basal half should be cultured in MS medium supplemented with TDZ at 4.4 µM and the apical half with TDZ at 2.2 µM. Subculturing individual shoots in MS medium without plant growth regulators allows further development and rooting. A survival rate of more than 90% under greenhouse conditions was achieved. This research represents a direct contribution to the conservation and sustainable use of this valuable natural resource.

A new giant species of placented worm and the mechanism by which onychophorans weave their nets (Onychophora: Peripatidae)

Onychophorans, or velvet worms, are poorly known and rare animals. Here we report the discovery of a new species that is also the largest onychophoran found so far, a 22 cm long female from the Caribbean coastal forest of Costa Rica. Specimens were examined with Scanning Electron Microscopy; Peripatus solorzanoi sp. nov., is diagnosed as follows: primary papillae convex and conical with rounded bases, with more than 18 scale ranks. Apical section large, spherical, with a basal diameter of at least 20 ranks. Apical piece with 6-7 scale ranks. Outer blade 1 principal tooth, 1 accessory tooth, 1 vestigial accessory tooth (formula: 1/1/1); inner blade 1 principal tooth, 1 accessory tooth, 1 rudimentary accessory tooth, 9 to 10 denticles (formula: 1/1/1/9-10). Accessory tooth blunt in both blades. Four pads in the fourth and fifth oncopods; 4th. pad arched. The previously unknown mechanism by which onychophorans weave their adhesive is simple: muscular action produces a swinging movement of the adhesive-spelling organs; as a result, the streams cross in mid air, weaving the net. Like all onychophorans, P. solorzanoi is a rare species: active protection of the habitat of the largest onychophoran ever described, is considered urgent.

Effect of Final Irrigation Regimen on Sealer Penetration in Curved Root Canals

IntroductionThe purpose of this study was to evaluate the effect of different final irrigation regimens on the sealer penetration into dentinal tubules of curved root canals. MethodsThe mesiobuccal canals from 45 extracted maxillary and mandibular molars were instrumented with sodium hypochlorite (NaOCl) irrigation. The samples were divided into 3 groups according to the final irrigation used: group N (control), 3.5% NaOCl; group E, 17% ethylenediaminetetraacetic acid (EDTA); and group EN, 17% EDTA followed by 3.5% NaOCl. All teeth were obturated with gutta-percha and AH Plus sealer labeled with fluorescent dye. Transverse sections at 2 mm (apical) and 5 mm (coronal) from root apex were examined by using confocal laser scanning microscopy. Then, total percentage and maximum depth of sealer penetration were measured. ResultsThe apical sections in each group showed significantly lower percentage and maximum depth of sealer penetration than the coronal sections (P < .05). In apical levels, group E and EN resulted in a higher percentage of sealer penetration than the control group (P < .05), but there was no significant difference of maximum depth between group E and the control group (P > .05). ConclusionsIn curved canal, final rinse with NaOCl after the use of EDTA had no additional effect on sealer penetration. Complete debridement with a 1-minute application of EDTA remains a challenge in the apical area of curved canals.

Effects of radicular dentin treatments and luting materials on the bond of quartz fiber posts: scanning electron microscope study

To investigate the effects of radicular dentin treatments of sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) on the regional root canal bonding interface of quartz fiber posts using 2 luting materials with SEM analysis. Nine intact maxillary central incisors were sectioned and endodontically treated. Standardized post space preparations and acid etch were performed. All specimens were randomly divided into 3 groups (n = 3). D.T.LIGHT posts were placed into the root canal using one of three radicular dentin treatments (0.9% NaCl for 60 s, 10% NaOCl for 60 s, 17% EDTA for 60 s followed by 5.25% NaOCl for 60 s) in combination of one of two luting materials (DuoLink, LuxaCore) respectively (factorial design). Cervical, middle, apical sections of each teeth are used for SEM study and spectroscopy of dispersion energy (EDS) microanalysis. With the radicular dentin treatment with 10% NaOCl alone or with 17% EDTA followed by 5.25% NaOCl, longer and increased number of penetration of resin tags into the dentinal tubules were observed at the resin-dentin interfaces, and adhesive lateral branches could be found easily. EDS microanalysis showed increase in the infiltration behavior of the luting cement. Radicular dentin treatments provide good resin infiltration, which can produce a three-dimensional interlocking micronetwork of resin tags in the dentin tubules with multiple lateral branches that penetrate the intertubular dentin, thus positively influence the adhesion between dentin and the luting materials.

Characteristics of Sugar Content in Different Sections and Harvest Maturity of Bamboo Shoots

Bamboo shoots (Phyllostachys pubescens Mazel) harvested from two cultivation areas were used to investigate the amount of accumulated sugars (sucrose, glucose, and fructose) in four sections along the length of a bamboo shoot. Bamboo shoots harvested from above ground (emerged bamboo shoot) and underground of the same cultivation area were also used to study the changes in sugar content during storage at both 5 and 25 °C. The amounts of sucrose, glucose, fructose, and total sugar of underground bamboo shoots were higher than those of emerged shoots. Sucrose content in the apical section was significantly higher than that in other sections. Meanwhile, higher amounts of glucose, fructose, and total sugar (the sum of sucrose, glucose, and fructose) were observed in the basal section. Changes in sugar content were also observed during storage. The fresh, unpeeled bamboo shoots have particular cellular chemical properties and respond differently to storage duration and condition depending on harvest maturity.

Description of Pseudocirrhipathes (Cnidaria: Anthozoa: Hexacorallia: Antipathidae), a new genus of whip black corals from the Indo‐Pacific

The new species, Pseudocirrhipathes mapia, is herein described from specimens coming from the coral reefs of the Bunaken Marine Park (North Sulawesi, Indonesia). The species is characterized by an unbranched thin corallum up to 1 m high (maximum basal thickness 4 mm), with large polyps arranged irregularly on one side of the stem, and by tentacles that are not completely contractile. The skeleton shows an array of spine morphologies along the stem, although most are typically verticillated in the apical section and highly tuberculated in the central portion. The study of its cnidome revealed the presence of an extremely long basitrich isorhiza. The morphological analysis has been coupled with a molecular study of the rDNA ITS sequences confirming the existence of the new genus Pseudocirrhipathes and its inclusion, together with the genus Allopathes, in a separate clade related to the Antipathidae.

Pulmonary arterial medial smooth muscle thickness in sudden infant death syndrome: an analysis of subsets of 73 cases

Previous studies addressing pulmonary artery morphology have compared cases of sudden infant death syndrome (SIDS) to controls but none have compared demographic profiles, exposure to potentially hypoxic risk factors and other pathologic variables in SIDS cases grouped according to pulmonary artery medial smooth muscle thickness. Aims: To compare the relative medial thickness (RMT) in alveolar wall arteries (AW) in SIDS cases with that in age-matched controls and 2. Compare demographic, clinical, and pathologic characteristics among three subsets of SIDS cases based upon alveolar wall (AW) RMT. Retrospective morphometric planimetry of all muscularized arteries in standardized right apical lung sections in 73 SIDS cases divided into three groups based on increasing AW RMT as well as 19 controls age-matched to 19 of the SIDS cases. SIDS and age-matched control cases did not differ with respect to AW RMT or other demographic variables. The SIDS group with the thickest AW RMT had significantly more males and premature birth than the other groups, but the groups did not differ for known clinical risk factors that would potentially expose them to hypoxia. Pathologic variables, including pulmonary inflammation, gastric aspiration, intra-alveolar siderophages, cardiac valve circumferences, and heart and liver weights, were not different between groups. Age was not significantly correlated with RMT of alveolar wall and pre-acinar arteries but was significant at p = .018 for small intra-acinar arteries. The groups were different for RMT of small pre-acinar and intra-acinar arteries, which increased with increasing AW RMT. Statistical differences should not necessarily be equated with clinical importance, however future research incorporating more quantified historical data is recommended.

Effectiveness of HERO 642 versus Hedström files for removing gutta‐percha fillings in curved root canals: an ex vivo study

To compare the effectiveness of gutta-percha removal and the maintenance of canal anatomy when using the HERO 642 system or Hedström files (H-files) in mandibular molar teeth. The root canals of 40 mandibular molar teeth were instrumented using H-files and filled with gutta-percha and sealer. After 1 year in storage, the roots were sectioned horizontally to provide apical, middle and coronal root thirds. Sections were photographed, and an individual muffle was produced for each tooth. Teeth were randomly divided into four groups (n = 10) and the gutta-percha removed using either the HERO 642 system or H-files, with or without solvent. Digital images of the root canals were then re-taken. Root thirds were inspected for lateral perforations, and the percentage of the residual canal filling was determined on postoperative images. Transportation and centring ratio were calculated using preoperative and postoperative images of the cross-sections of root thirds. H-files groups were associated with less filling material than the HERO 642 system (H-files-HERO 642 P = 0.056, H-files-HERO 642+solvent P = 0.041, H-files + solvent-HERO 642 P = 0.018, H-files + solvent-HERO 642 + solvent P = 0.016). The percentage of residual filling material was similar in the apical thirds, and the contribution of solvent to canal debridement was not statistically significant (P > 0.05). Perforation occurred mesiobuccally in 48% of specimens in the apical sections of mesial roots. There were no significant differences for centring ratio, transportation and perforation rate between groups. H-files left less gutta-percha overall; however, there was no difference in the apical third. The effect of solvent was not remarkable. Both instrument systems created a large number of perforations.

Evaluation of Dentinal Tubule Penetration after the Use of Dentin Bonding Agent as a Root Canal Sealer

Introduction The purpose of this study was to compare the effectiveness of Excite DSC (Ivoclar Vivadent, Schaan, Liechtenstein), a dentin bonding agent, with AH-26 (Dentsply, Detrey, Germany) as a root canal sealer by evaluating the penetration depth into the dentinal tubules and the tag density of the two compounds. Methods Forty-two extracted, single-rooted premolars were prepared and randomly obturated with either Excite DSC ( n = 20) or AH-26 ( n = 20). Two teeth were filled without sealer and used as controls. Randomly, one half of the specimens in each group ( n = 10) was sectioned 3 days after obturation (short-term), and the other half ( n = 10) was sectioned after 3 months (long-term). The specimens were sectioned perpendicular to the long axis in two regions and prepared for observation using scanning electron microscopy. Results In the short-term evaluation, the mean penetration depth of AH-26 in the apical sections (520.48 μmol/L) was significantly higher than that of Excite DSC (0.00 μmol/L). In the long-term evaluation, AH-26 exhibited a significantly greater depth of penetration in both the apical (797.74 μmol/L) and middle sections (1162.11 μmol/L) than Excite DSC (321.43 μmol/L and 657.72 μmol/L, respectively). Conclusion AH-26 showed more dentinal tubule penetration depth than Excite DSC in both evaluation periods.

Deposição da calda de pulverização em cultivares de soja no estádio R1

Com o objetivo de quantificar a quantidade e a uniformidade dos depósitos da calda de pulverização em duas cultivares de soja ('CD 208' e 'CD 216'), no estádio R1, por meio de diferentes pontas e volumes de pulverização, foram conduzidos dois experimentos na área, na Faculdade de Ciências Agronômicas UNESP- Botucatu, São Paulo (SP). Os tratamentos avaliados foram: pontas de jato plano (AI 110015 a 150L ha-1, AI 11002 a 200 e 250L ha-1); pontas de jato plano duplo (TJ 60 11002 a 150, 200 e 250L ha-1); pontas de jato cônico (TX-6 a 150, TX-8 a 200 e TX-10 a 250L ha-1) e pontas de jato plano duplo e baixa deriva (DGTJ 11002 a 200L ha-1). O delineamento utilizado foi de blocos ao acaso com quatro repetições. Para a avaliação da deposição, foi utilizado na pulverização o corante Azul Brilhante FDC- 1 (500mg L-1). Foram coletadas 25 plantas em cada repetição, divididas em região basal e apical. A determinação do conteúdo depositado foi realizada com a leitura de absorbância no comprimento de onda de 630nm, e os dados transformados em depósitos por grama de matéria seca foram ajustados às curvas de regressão, por meio do modelo de Gompertz. Os maiores depósitos avaliados nas cultivares 'CD 208' e 'CD 216' corresponderam aos tratamentos AI 11002 250L ha-1 e TJ 60 11002 250L ha-1, respectivamente. Os resultados da uniformidade da distribuição da calda de pulverização foram contraditórios aos da quantidade de depósitos. Em todas as avaliações, o tratamento de maiores depósitos apresentou menor uniformidade na distribuição.