Apical Portion Research Articles

Hoverfly pollination enhances yield and fruit quality in mango under protected cultivation

Mango (Mangifera indica L.) is one of the main tropical fruit crops worldwide. Although mostly grown in open fields, protected cultivation of mango has recently increased. Pollination in mango mainly occurs by flies (myophily) among which the group of eristaline hoverflies (Diptera: Syrphidae) stands out. Greenhouse studies were conducted on the pollination services provided by Eristalinus aeneus released at three densities in a protected mango orchard in southern Spain, during two consecutive seasons (2019 and 2020). Medium and high densities (30 and 45 individuals per square meter, respectively) led to higher number of floral visits to the middle and apical portions of the inflorescences where hermaphrodite flowers are more common, which resulted in more pollen grains being transferred to the stigma of fertile flowers. Medium and high densities of E. aeneus increased yields and improved fruit quality compared to low density (15 individuals per square meter), no insect release, and conventional pollination management using bumblebees. Yield enhancement achieved by using hoverflies as pollinating agents at medium and high densities implies an economic gain for farmers ranging from 16% to 29% in 2019 and from 212% to 456% in 2020. Therefore, our results suggest that medium and high densities of E. aeneus are profitable pollination solutions for mango cultivated under greenhouses.

Antimicrobial effects of agitational irrigation on single- and multispecies biofilms in dentin canals.

This study aimed to compare the antibacterial effects of different agitation devices on single- and multispecies biofilms in dentin canals using confocal laser scanning microscopy (CLSM). Dentin blocks were prepared from human root dentin. Enterococcus faecalis and multiple species were introduced into the dentinal tubules via centrifugation and incubation. Two infected dentin samples were placed at 8 and 16mm in a customized model. Samples were randomly divided into eight groups according to the agitation device used: syringe needle irrigation, EndoActivator, passive ultrasonic irrigation (PUI), and EDDY, at 2.5% or 6% NaOCl concentrations. The samples were stained and observed using CLSM. Statistical analysis was performed using an independent sample t test and analysis of variance. Linear models were used to assess the joint impact of the experimental groups on the proportion of biofilms killed. No significant differences were observed between the killing rates of the single- and multispecies biofilms. Both concentrations of NaOCl significantly increased the percentage of dead bacteria compared with the control. Biofilms in dentin tubules was more effectively killed when NaOCl was agitated; however, the difference between PUI and EDDY was not significant. Significantly more bacteria were killed in dentin blocks placed at 8mm than at 16mm (p < 0.05). In conclusion, EDDY was as effective as PUI when combined with NaOCl. However, the apical portion, which had a low antimicrobial efficiency, remains a concern. Mechanical instrumentation is incapable of completely eradicating bacteria, and additional research is required to improve the efficacy of root canal disinfection.

Influence on Implant Bone Healing of a Collagen Membrane Placed Subjacent the Sinus Mucosa-A Randomized Clinical Trial on Sinus Floor Elevation.

Background: Perforation of the sinus mucosa is quite a frequent complication that might occur during sinus floor elevation. The perforation is often protected with a collagen membrane to avoid the extrusion of graft particles within the sinus. However, this procedure might hinder the innate osteogenic potential of the sinus mucosa. Hence, the aim of the study was to evaluate the influence of a placement of a collagen membrane subjacent the Schneiderian membrane during sinus floor elevation on implant bone healing. Methods: Twenty volunteers took part in the trial. Ten were randomly included in the group that received a collagen membrane subjacent the sinus mucosa (Mb group), and ten did not receive the membrane (non-Mb group). A collagenated corticocancellous porcine bone was used to fill the elevated space. Six 6 months after the sinus floor elevation, a mini implant was placed transcrestally and retrieved after a further 3 months. Histological analyses were then performed on the full body of the mini implant as well as on its coronal and apical portions. Results: The new bone apposition proportion onto the implant surface was similar in the Mb and non-Mb groups, both in the apical and coronal portions of the mini implants. A lesser amount of graft was found in contact with the surface. New bone density around the mini implants were similar both in the apical and coronal portions. However, a statistically higher proportion of graft particles was found in the Mb group compared to the non-membrane group. Conclusions: The placement of a collagen membrane subjacent the sinus mucosa did not affect bone healing at implants and bone density.

Osteotomy combined with the trephine technique for invisible implant fracture: A case report

BACKGROUNDImplant fracture is one of the most serious mechanical complications of dental implants. Conventional treatment necessitates visibility of the apical portion of the fractured implant, whereas for deep and invisible implant fractures, the traditional trephine method has been ineffective. Surgical removal of the marginal bone to expose the fracture surface would be a time-consuming and extensively damaging procedure. Here, we propose a novel technique to address invisible implant fractures.CASE SUMMARYA 50-year-old woman was referred to our department with the chief complaint that her right mandibular implant tooth had fallen out 3 mo earlier. Cone-beam computed tomography examination showed an implant fracture with a fracture surface 5.1 mm below the crestal ridge. The patient was treated with osteotomy combined with the trephine technique to expose the surgical field and remove the implant. The invisible fractured implant was successfully removed, with minimal trauma. A modified Wafer technique-supported guided bone regeneration treatment was then administered to restore the buccal bone wall and preserve the bone mass. Six months later, fine regenerative bone and a wide alveolar crest in the edentulous area were observed, and a new implant was placed. Four months later, restoration was completed using a cemented ceramic prosthesis. Clinical and radiographic examinations 12 mo after loading fulfilled the success criteria. The patient reported no complaints and was satisfied.CONCLUSIONOsteotomy combined with the trephine technique can be effectively used to address deep and invisible implant fractures.

A New Species of Septuconularia (Hexangulaconulariidae, Cnidaria) from Cambrian Stage 2, South China

AbstractHexangulaconulariids, an extinct family of medusozoan small shelly fossils (SSFs), were a conspicuous component of early Cambrian, shallow marine platform communities in South China. Described herein is Septuconularia crassiformis sp. nov. from Bed 5 of the Yanjiahe Formation (Cambrian Stage 2) in the Three Gorges area of Hubei Province. The new species differs from the type and only other known species, S. yanjiaheensis, in the shape of the abapical portion and in the degree of curvature of the adapertural margin. The anatomy of the apical portion of the new species is unknown. The diagnosis of the genus Septuconularia is emended and the spatio‐temporal distribution of hexangulaconulariids in South China is summarized. Finally, S. yanjiaheensis, with its slit‐like aperture and very narrow transverse cross‐section, may have been better adapted to the shallow platform environment than the broader S. crassiformis, which appears to have been less common than the type species.

P116 GIANT LEFT ATRIAL MYXOMA CAUSING ACUTE ISCHEMIC STROKE

Abstract Aims Primary cardiac tumours are rare; most are benign, and around half are myxomas, often located in the left atrium. Clinical presentation is variable. Ischaemic stroke is a rare, although real and potentially fatal, complications of cardiac myxomas. Case Report We present a case of a 51–year–old man, ex– smoker, obese, with history of hypertension and COPD, presented to our emergency department with right–sided hemiplegia and aphasia caused by ischaemic stroke. Brain CT revealed cerebral perfusion deficit. The patient was underwent intravenous thrombolytic strategy. TTE showed a large left atrial mass attached to the interatrial septum, with a friable appearance, suggestive of myxoma. The 2D and 3D TEE detected a giant space–occupying mass in the left atrium, coral–like, and the most apical portion prolapsed into the left ventricle during diastole, causing fixed obstruction to flow in the left ventricular inflow tract. In view of the risk of imminent embolization, the emergent surgical excision of the tumour was performed. Subsequent histopathological findings confirmed the diagnosis of myxoma. Symptomatic cardiac myxoma may present with one of the three classic clinical presentations of the Goodwin’s triad, which include intracardiac obstruction, constitutional symptoms, and embolism. The obstructive pattern mimics atrioventricular valve obstruction. Constitutional manifestations include fatigue, fever, weight loss. Systemic embolization from myxoma occurs in around a third of cases. Of these, the most serious is cerebrovascular embolism, which may result in cerebral stroke. The tumour size, location, and macroscopic appearance, along with mean platelet volume and platelet count, are closely associated with embolic events. Echocardiography remains the method of choice for diagnosis and morphological characterization of myxoma. Two patterns have been established by echocardiography: round, with a solid appearance and a firm surface, and polypoid, with an irregular outline and a friable surface. The incidence of systemic embolization is higher in those with an irregular and friable surface and those that prolapse into the ventricle. Once a diagnosis of myxoma is established, surgical resection is the only effective treatment and should be performed immediately, in view of the risk of embolization. Conclusions With this case report, we stress the importance of echocardiography in new onset of neurological deficit to prevent potentially fatal outcomes.

P245 A RARE CAUSE OF OVERESTIMATION OF PULMONARY PRESSURE BY ECHOCARDIOGRAPHY: WHEN HEMODYNAMICS RELIEVES ECHOCARDIOGRAPHY AND ECHOCARDIOGRAPHY EXPLAINS HEMODYNAMICS

Abstract Echocardiography is the gatekeeper of the diagnostic workflow of pulmonary hypertension (PH). However, it lacks precision, and right heart catheterization (RHC) may be needed in selected cases. A morbidly obese 47–year–old woman (BMI= 58 Kg/m2) with dyspnea NYHA II was referred to our Center after a high probability of PH was found at echocardiography, this latter performed as a routine assessment before bariatric surgery. Despite a suboptimal acoustic window, the tricuspid regurgitant jet profile was well–defined, with an estimated systolic pulmonary artery pressure (PAP) of 100 mmHg. There were no overt echocardiographic signs of left heart disease. During RHC, mean PAP was just above normal values, with filling pressures at the upper limit of normal (Figure 1), high cardiac index (3.6 L/min/m2) and normal pulmonary vascular resistance (1.4 WU). The echocardiographic estimate of high systolic PAP was explained by an intraventricular RV pressure gradient of about 100 mmHg (Figure 2). Oximetry ruled out a significant intracardiac shunt. Since resting hemodynamics did not explain the patient’s symptoms, the patient pre–test probability of having heart failure with preserved ejection fraction (HFpEF) was intermediate–high, and PAWP was in a grey–zone. Accordingly, we performed an exercise RHC. The test eventually unmasked HFpEF, as witnessed by an abnormal increase of PAWP and LV end–diastolic pressure (Figure 1 panel C and D). Exercise capacity was mildly reduced (71% of predicted) due to peripheral limitation with normal cardiac and respiratory reserves. Transesophageal echocardiography was then performed. It showed a muscular obstruction below the infundibulum dividing the RV into a high–pressure apical portion and a low–pressure infundibulum (Figure 3). This rare congenital anomaly was also associated with a restrictive perimembranous ventricular septal defect. Double–chambered RV has been reported to present rarely in adults, but it might be a cause of false Doppler echocardiographic estimate of PAP. Based on a meticulous invasive hemodynamic characterization at rest and during exercise, integrated with cardiovascular imaging, we could perform such a diagnosis. This congenital anomaly did not fully explain the patient’s symptoms, which may better be attributed to cardiovascular complication of obesity (HFpEF). Accordingly, we referred the patient for bariatric surgery first, postponing the indication to cardiac surgery during the follow–up.

C44 VENTRICULAR TACHYCARDIA IN PATIENT WITH PSEUDOISCHEMIC VENTRICULAR SCAR

Abstract We describe a case of 76 years old men. He was referred to emergency room for chest pain and short of breath. The medical history escluded pre–existent miocardial infarction, no history of fever and chest pain has been declared,.The electrocardiogram (ECG) showed a 200 pbm tachycardia with right bundle branch and right axial deviation. The transition was in V4 (Fig. 1). The tachycardia was not tolerated and after ineffective administration of amiodarone, the tachycardia was terminated by DC shock (200 J synchronized). We performed an echocardiogram with evidence of minimal ventricular dilatation, the inferior–posterior–lateral akinesia, inferior–posterior scar and severe reduction of ejection fraction (about 30%). For better characterization of the scar, we performed cardio magnetic resonanc imaging with evidence of significative thinning of the left ventricle free wall and trasmural LGE of the of left ventricle free wall suggest ischemic myocardial injury (Fig. 2 a,b,c,d,e). The coronary arteriography was performed without evidence of critical coronary stenosis.We decide to implant a single lead ICD. After one month, because of recurrence of tachycardia, we performed the electrophysiological study. We induced clinical ventricular tachycardia and the electroanatomical mapping highlighted an area of anomalous potentials extended in the infero–posterior and lower–basal region more at the epicardial level. In these areas, at the epicardial level, late potentials were highlighted and the ablation performed making the tachycardia no longer inducible. Despite of evidence of pseudo–ischemic scar localized at the basal portion of ventricle at the cardiac MRI, no critical coronary stenosis has been demonstrated and the arrhythmogenic substrate was exclusively epicardic. The preliminary hypothesis was a MINOCA, not of recent onset considering the negativity of myocardial enzymes at the admission and the absence of acute ischemic changes on post cardioversion ECG.We have therefore also considered forms of previous extensive myocarditis however with the limited longitudinal extension. From what has been described in the literature, the MRI images could also be attributable to a form of left ventricle arrhythmogenic dysplasia even in the absence of involvement of the apical portions. Forms of infiltrative cardiomyopathies such as sarcoidosis should be excluded due to the lack of involvement of the interventricular septum.

The effectiveness of different irrigation strategies with laser activation on the bond strength of MTA as root end filling material: in vitro study

ObjectiveTo compare the push out bond strength of MTA apical plug in a simulated immature root, after using different irrigation protocols; NaOCl + 20% Etidronic acid (HEBP) and NaOCl + 17% Ethylenediaminetetraacetic acid (EDTA) with and without diode laser activation.MethodsTwenty-eight extracted single straight rooted permanent human teeth were selected. The root lengths were standardized (15 mm) by decronation of all samples. Instrumentation was done using the ProTaper Next system (Dentsply Sirona), the canals were flushed with 1 mL NaOCL after each instrument. Then, the apical 3 mm was cut perpendicular to the root’s long axis and the canals were prepared till file 90( master file) using the balanced force technique to simulate immature teeth. Samples were divided into four experimental groups (n = 7) in accordance with the irrigation protocol; G1 (NaOCl + HEBP), G2 (NaOCl + EDTA) both G1 and G2 were activated with diode laser, while G3 (NaOCl + HEBP) and G4 (NaOCl + EDTA) were activated with manual agitation. Canals were filled with a 5-mm MTA (ProRoot MTA, Dentsply Tulsa Dental) apical plug. Each root was transversely sectioned perpendicular to their long axis to have a 3 mm ± 0.1sections in thickness from the root apical portion. A push-out test was performed, and the failure pattern was assessed. Push out bond strength values were analyzed with student t test for compared pairs. Two-way ANOVA was used to detect the effect of each variable (chelating agent with/without laser activation).ResultEffect of diode laser activation in G1 and G2 showed no significant differences (p > 0.05) on the push out bond strength values of MTA, while in manual activated groups (G3 and G4), there was a statistically significant difference (p < 0.05) where G4 recorded higher push out bond strength mean values than G3.ConclusionsThe diode laser activation when used with NaOCL and HEBP increased the effect of HEBP as chelating agent and improved the push out strength values of MTA, rendering it an alternative mild chelating agent in comparison with the EDTA.

Dimensional and morphologic characteristics of unilateral impacted maxillary central incisors

This cross-sectional study aimed to investigate the crown and root characteristics of impacted central incisors compared with spontaneously erupted contralateral incisors and the influence of etiologic and local factors on their dimensions. Forty-five patients (22 boys, 23 girls) who underwent orthodontic treatment for unilateral impaction of maxillary central incisors were referred for cone-beam imaging. Dimensions of the impacted and contralateral incisors were assessed using Dolphin 3D software (Dolphin Imaging & Management Solutions, Chatsworth, Calif). Paired t test and linear regression were used to compare the characteristics of the impacted and contralateral teeth. Contralateral and impacted central incisors showed statistically significant differences for root length (95% confidence interval [CI], 2.32-3.46; P<0.001), mesiodistal crown-root angulation (95% CI, 4.09-15.95; P= 0.001), and labiolingual crown-root angulation (95% CI, -18.69 to -4.70; P= 0.002). Etiologic factors did not alter the dimensions of incisors (95% CI, -1.17 to 0.76; P= 0.672). According to the multiple linear regression the independent variables associated with root length of contralateral and impacted incisors were sex (β= -0.904; 95% CI, -1.62 to - 0.19; P= 0.014) and the presence of impaction (β= -2.87; 95% CI, -3.67 to -2.07; P<0.001). Regardless of their etiology, the impacted incisors showed roots that were 2.89 mm shorter than the contralateral incisors and had greater angulation in the mesiodistal and labiolingual directions. Girls showed a reduction of 0.904 mm (7.6%) on the lengths of roots of both impacted and contralateral central incisors. The presence of impaction led to a reduction of 25% in incisor root lengths. Approximately 30% of the impacted teeth showed crown-root angulations>20° resulting in an increased distal and labial angulation of the root apical portion.

Current Trends in Root Canal Irrigation.

Chemical and mechanical root canal debridement are the primary methods used in endodontic therapy to remove all dead tissue, bacteria, and microbial byproducts from the canal. Sodium hypochlorite, a powerful organic tissue dissolver with a broad spectrum of antibacterial properties, is an excellent choice for disinfecting surfaces. Chelating agents, on the other hand, may be used to remove the inorganic components found on the smear layer. This irrigation method is capable of removing the smear layer; however, it is less effective in the apical third. While using irrigant activation devices, irrigating solutions need to be in direct contact with the whole root canal wall surfaces, especially in the apical portions of tiny root canals. The role of irrigants is extremely important because they help not only to clean the canal but also to allow the seepage of the medicaments into the canal system. Thus, the canal needs to be healthy before the obturation procedure. Nowadays, many irrigants have been studied and hence compilation of the various available sources and their effect has to be studied both in vivo and in vitro. The correlation between the irrigants and the canal cleanliness is of utmost importance, as the success of endodontic root canal treatment depends on its proper activation and characteristics. Hence, this review incorporates the current use of various irrigating solutions and their advantages and disadvantages. In the future, endodontists may employ the novel irrigants and irrigant activation devices that were discovered in this study.

Influence of Implant Diameter and Taper on Virtual Implant Placement in the Maxillary Central Incisor Position: A CBCT Analysis.

This study aimed to assess the influence of implant diameter and taper on the proximity of virtually planned maxillary central incisor implants to the nasopalatine canal and adjacent anatomical structures. Virtual implant planning was performed in the maxillary central incisor position. The distance between the implant and the incisive canal (IC) and the thickness of the surrounding buccal and palatal bone walls were measured. Implants were categorized as having an exposed implant surface, thin bone, or moderate/thick bone. Measurements were repeated for regular-/narrow-diameter and parallel/tapered implants. A total of 60 patients were included, and 240 implants (60 of each type: 3.3-bone level [BL], 3.3-bone level tapered [BLT], 4.1-BL, and 4.1-BLT) were planned. The percentages of implants with between 0 and 0.5 mm of remaining bone in the coronal aspect of the IC were 31.6% for 4.1-BL/BLT and 6.6% for 3.3-BL/BLT (P < .001). The percentage of implants with IC exposure was 13.3% for 4.1-BL/BLT and 6.6% for 3.3-BL/BLT (P < .001). The frequency of sites that required bone augmentation at the coronal facial aspect (< 1 mm) was 52.6% and 33.9% for 4.1-BL/BLT and 3.3-BL/BLT, respectively. At the apical portion, the percentages of sites requiring bone augmentation at the facial aspect were 59.9%, 49.9%, 31.6%, and 23.3% for 4.1-BL, 3.3-BL, 4.1-BLT, and 3.3-BLT, respectively (P < .001). The proximity of the nasopalatine canal is often < 0.5 mm from regular-diameter virtually planned implants at the most coronal aspect in the maxillary central incisor position. In these situations, the selection of narrowdiameter implants significantly lowers the incidence of implant exposure and the need for additional management of the nasopalatine canal and also results in greater residual buccal and lingual bone thicknesses surrounding the implant. As expected, tapered implants reduced the risk of implant exposure through the buccal cortex at the apical aspect.

Rab39 and its effector UACA regulate basolateral exosome release from polarized epithelial cells.

Exosomes are small extracellular vesicles that originate from the intraluminal vesicles of multivesicular bodies (MVBs). We previously reported that polarized Madin-Darby canine kidney (MDCK) epithelial cells secrete two types of exosomes, apical and basolateral exosomes, from different MVBs. However, how these MVBs are selectively targeted to the apical or basolateral membrane remained unknown. Here, we analyze members of the Rab family small GTPases and show that different sets of Rabs mediate asymmetrical exosome release. Rab27, the best-known regulator of MVB transport for exosome release, is specifically but partially involved in apical exosome release, and Rab37, a close homolog of Rab27, is an additional apical exosome regulator. By contrast, Rab39 functions as a specific regulator of basolateral exosome release. Mechanistically, Rab39 interacts with its effector UACA, and UACA then recruits Lyspersin, a component of BLOC-1-related complex (BORC). Our findings suggest that the Rab39-UACA-BORC complex specifically mediates basolateral exosome release.

Ventriculography for the study of TAKO-TSUBO Syndrome

Tako-Tsubo Cardiomyopathy (TTC) is an acute syndrome, identified in the early 1990s by Japanese researchers, which mimics an acute myocardial infarction. Cardiomyopathy is transient and begins with a clinical picture similar to that of an acute myocardial infarction. This pathology seems to be related to intense psychological and physical stress with a prevalence in the female sex (95%) in post-menopause. The term Tako-Tsubo means ‘octopus trap’ in Japanese: the left ventricle takes on a peculiar appearance in systole, similar to a narrow-necked amphora, morphologically identical to the vessel (tsubo) that Japanese fishermen use to catch octopuses (tako). The appearance of the left ventricle (tako-tsubo shape) is due to a ‘complete’ depletion of cardiac muscle activity (myocardial stunning), a kind of ‘stunning’ or paralysis of the middle and apical portions of the heart. Coronarography and ventriculography are an essential step in the diagnosis of TTC. The mere demonstration of a coronary tree free of angiographically significant stenosis is not sufficient for the diagnosis of TTC. The other key diagnostic element is, in fact, the demonstration of left ventricular hypokinesia or akinesia. Since left ventricular wall motility disorders change rapidly, ventriculography performed immediately after coronary examination is the gold standard examination to allow the characteristic appearance of the syndrome to be verified and, consequently, to distinguish it from an acute coronary syndrome with uninjured coronary arteries, thus avoiding a diagnostic error.

Ventriculography for the study of TAKO-TSUBO Syndrome

Tako-Tsubo Cardiomyopathy (TTC) is an acute syndrome, identified in the early 1990s by Japanese researchers, which mimics an acute myocardial infarction. Cardiomyopathy is transient and begins with a clinical picture similar to that of an acute myocardial infarction. This pathology seems to be related to intense psychological and physical stress with a prevalence in the female sex (95%) in post-menopause. The term Tako-Tsubo means 'octopus trap' in Japanese: the left ventricle takes on a peculiar appearance in systole, similar to a narrow-necked amphora, morphologically identical to the vessel (tsubo) that Japanese fishermen use to catch octopuses (tako). The appearance of the left ventricle (tako-tsubo shape) is due to a 'complete' depletion of cardiac muscle activity (myocardial stunning), a kind of 'stunning' or paralysis of the middle and apical portions of the heart. Coronarography and ventriculography are an essential step in the diagnosis of TTC. The mere demonstration of a coronary tree free of angiographically significant stenosis is not sufficient for the diagnosis of TTC. The other key diagnostic element is, in fact, the demonstration of left ventricular hypokinesia or akinesia. Since left ventricular wall motility disorders change rapidly, ventriculography performed immediately after coronary examination is the gold standard examination to allow the characteristic appearance of the syndrome to be verified and, consequently, to distinguish it from an acute coronary syndrome with uninjured coronary arteries, thus avoiding a diagnostic error.

Present status and future directions of intracanal medicaments

Two fundamental goals of endodontic treatment are to prevent or treat apical periodontitis. From a predictive perspective, several variables can affect the outcome of root canal treatment. Some of these variables depend on intraoperative factors, which include irrigation technique, size of the apical preparation, use of intracanal medicaments or the number of appointments necessary to complete the treatment. However, the outcome may also be affected by host and microbial factors. The intensity of periradicular bone loss or tissue damage, the presence of preoperative pain and associated conditions such as mechanical allodynia and central sensitization, the anatomical complexity of the apical portion of the canal, and the virulence and longevity of the bacterial infection can all have a profound influence on the outcome. Furthermore, numerous medical conditions have been reported to decrease the capability of the immune system to heal the periapical tissues. It is the clinician's responsibility to analyse these variables and incorporate them into the disinfection strategy to maximize the chances of healing. This narrative review will focus on the present status of intracanal medicaments, the clinical indications for their use and future directions for research.

Comparison of Two Root Canal Filling Techniques: Obturation with Guttacore Carrier Based System and Obturation with Guttaflow2 Fluid Gutta-Percha.

Introduction: The aim of the present study was to compare the quality of the root canal obturation obtained with two different techniques, i.e., thermoplastic gutta-percha introduced through a carrier (GuttaCore) and fluid gutta-percha (GuttaFlow2). Materials and Methods: The study included 40 permanent single-rooted human teeth, divided into two groups and obturated with Guttaflow (group G) and with GuttaCore (group T). The teeth were fixed and transversely sectioned, they were examined by scanning electron microscopy. The dentin–cement–gutta–percha interface and the percentage of voids produced by the two techniques were statistically analyzed. Results: GuttaCore showed a better filling in the apical third of the canal with a percentage of voids equal to 5%. GuttaFlow showed a lower percentage of voids in the middle and coronal thirds of the canal, 1.6% of coronal voids. Statistical analysis showed a statistically significant difference in the percentage of voids in the two groups (GuttaCore and Guttaflow2) in each portion. Conclusions: GuttaFlow2 seems to flow optimally in the middle and coronal third of the canal, with greater difficulty in filling the apical third. Due to the rigidity of the carrier, GuttaCore is able to reach better the most apical portions of the canals, with greater difficulty in creating the three-dimensional seal at the level of the middle third and coronal third.

Shaping Ability of Reciprocating and Rotary Systems After Root Canal Retreatment: a CBCT Study.

The purpose of this in vitro study was to evaluate the shaping ability of reciprocating and continuous rotary systems after root canal retreatment. After preparation and root canal filling, mesial canals of 54 mandibular molars were distributed into 3 groups (n=18), according to the filling material removal and re-instrumentation protocols: WOG group - WaveOne Gold system; PTN group - ProTaper Next system; and PTU group - ProTaper Universal system. Cone-beam computed tomographic (CBCT) images acquisition of the mesial root canals was performed at different moments: (1) before instrumentation (unprepared root canals), (2) after preparation and filling, (3) after filling material removal and (4) re-instrumentation. The apical transportation (AT), centering ability (CA) and change in root canal diameter were assessed by CBCT analysis. The remaining filling material quantification was performed by radiographic examination. The statistical analyses were performed using the 3-way ANOVA, Tukey-Kramer, Kruskal-Wallis and Dunn multiple Comparison tests (p<0.05). The tested instruments did not show full CA (=1.0). PTN group had greater AT at the 5th mm in comparison with the WOG group (p<0.05). After re-instrumentation, WOG group had greater root canal diameter change at the 1st and 5th mm than PTN and PTU groups (p<0.05). There was no significant difference among groups when comparing the amount of remaining filling material after re-instrumentation (p>0.05). The tested systems provided minimal alteration in root canal morphology at the apical portion after root canal retreatment. However, WOG promoted greater change in root canal diameter.

Effect of bioceramic root canal sealers on the bond strength of fiber posts cemented with resin cements.

This study aimed to evaluate the influence of calcium silicate-based sealers on the bond strength of fiber posts using conventional and self-adhesive resin cement. Sixty single-rooted teeth were selected. The canals were prepared with a reciprocating instrument 40.06. The roots were randomly distributed in six groups (n = 10) according to the strategies for root canal filling and fiber posts cementation: AH Plus/RelyX ARC; AH Plus/RelyX U200; Bio C Sealer/RelyX ARC; Bio C Sealer/RealyX U200; Sealer Plus BC/RelyX ARC; and Sealer Plus BC/RelyX U200. The roots were transversally sectioned, and one slice per post-third was obtained. The push-out test was performed at a crosshead speed of 1mm/min. The failure patterns were described after assessment with a stereomicroscope with a 10× magnification. Bond strength was calculated and analyzed using the ANOVA and Tukey test. AH Plus did not influence the bond strength of fiber posts cemented with conventional (RelyX ARC) or with self-adhesive resin cement (RelyX U200). The lowest bond strength values were obtained when calcium silicate-based sealers were associated with conventional resin cement (Bio C Sealer/RelyX ARC and Sealer Plus BC/RelyX ARC). Except for Sealer Plus BC/RelyX ARC, all groups presented lower bond strength at the apical portion compared to the cervical portion of the post. Adhesive failures between cement and post and cement and dentin were predominant (55.3%). Calcium silicate-based sealers decreased the bond strength of fiber posts cemented with conventional resin cement.

Using ultrasound multiple scattering to determine severity of pulmonary edema

Conventional ultrasound (US) cannot quantitatively evaluate lung tissue because of US multiple scattering (USMS). Pulmonary edema causes vertical artifacts -B-lines- which provide qualitative information about alveolar flooding. We showed that Scattering mean free path (SMFP), a measure of the density of air-filled alveoli, is longer in edematous than normal lungs. Here, we show that SMFP correlates with wet:dry weight ratio of lung tissue (W/D) and CT-scan assessment of edema. Ischemia-reperfusion injury (IRI) was created in lungs of anesthetized rats. The left lung hilum was clamped for 20, 40, or 60 minutes (n = 6/group) then reperfused for 60 minutes before ligating the apical portion of each lung to measure W/D, removing inflated lung blocks, then measuring SMFP and backscatter frequency shift (BFS) with a Verasonics scanner and L11-4v US probe. Six lung blocks were removed from healthy rats as Controls. Inflated lung blocks had ex vivo CT scans, followed by inflation-fixed histology. By logistic regression, there was a correlation between SMFP and W/D in 18 edematous and 12 Control lungs (r2 = 0.27, p &amp;lt; 0.004) and a significant correlation between edema extent by CT and SMFP and W/D. BFS was larger, and histology confirmed edema in IRI lungs. SMFP may be useful to quantify lung edema.