Characterization of controlled trials on probiotic supplementation to dairy calves: A scoping review.

The objective of this scoping review was to identify, describe, and characterize the literature on probiotic supplementation in dairy calves. Eligible studies were nonrandomized, quasi-randomized and randomized controlled trials in English, Spanish, or Portuguese that evaluated the effect of probiotic supplementation on growth and health of dairy calves. The search strategies were based on a modification of the PICO (Population, Intervention, Comparator, Outcome) framework and used synonyms and words related to "dairy calves" (population), "probiotics" (intervention), and "growth and health measurements" (outcomes). No restrictions for publication year or language were applied. Searches were conducted in Biosis, CAB Abstracts, Medline, Scopus, and the Dissertations and Theses Database. In total, the search identified 4,467 records, of which 103 studies (110 controlled trials) met the inclusion criteria. The studies were published between 1980 and 2021 and originated from 28 countries. Trials were randomized (80.0%), nonrandomized (16.4%), and quasi-randomized (3.6%), ranging in sample size from 5 to 1,801 dairy calves (mode = 24; average = 64). Enrolled calves were frequently Holstein (74.5%), males (43.6%), and younger than 15 d at the beginning of probiotic supplementation (71.8%). Often, trials were conducted in research facilities (47.3%). Trials evaluated probiotics with single or multiple species of the same genus: Lactobacillus (26.4%), Saccharomyces (15.4%), Bacillus (10.0%), Enterococcus (3.6%), or multiple species of various genera (31.8%). Eight trials did not report the probiotic species used. Lactobacillus acidophilus and Enterococcus faecium were the species most supplemented to calves. The duration of probiotic supplementation ranged from 1 to 462 d (mode = 56; average = 50). In trials with a constant dose, it ranged from 4.0 × 106 to 3.7 × 1011 cfu/calf per day. Most probiotics were administered mixed solely into feed (88.5%; whole milk, milk replacer, starter, or total mixed ration) and less frequently orally as a drench or oral paste (7.9%). Most trials evaluated weight gain (88.2%) as a growth indicator and fecal consistency score (64.5%) as a health indicator. Our scoping review summarizes the breadth of controlled trials evaluating probiotic supplementation in dairy calves. Differences in intervention design (mode of probiotic administration, dose, and duration of probiotic supplementation) and outcomes evaluation (type and methods) justify future efforts toward standardized guidelines in clinical trials.

The ALR-RSI score can be used to evaluate psychological readiness to return to sport after acute Achilles tendon tear.

PURPOSE: The return to sport is one of the main goals following Achilles tendon tear repair. Several psychological factors influence the return to sport after a sports injury. The traditional tools to assess the return to sport do not take into account psychological factors. The ankle ligament reconstruction-return to sport injury (ALR-RSI), validated for ankle instability, is a score to evaluate psychological readiness to return to sport. The goal of this study was to validate the ALR-RSI score for the assessment of the readiness to return to sport after Achilles tendon repair. METHODS: The ALR-RSI score, adapted from the anterior cruciate ligament-return to sport injury (ACL-RSI) score used following knee ligament reconstruction, was validated according to the international COSMIN methodology. Patients operated for Achilles tendon repair responded to the questionnaire during the rehabilitation period. The EFAS, FAAM and VISA-A scores were used as reference questionnaires. RESULTS: A total of 50 patients were included. The ALR-RSI score was strongly (r > 0.5) correlated to the EFAS score: r = 0.68 [0.50-0.80] the FAMM sport score: r = 0.7 [0.52-0.84] the FAAM AVQ score (r = 0.6 [0.35-0.78]), and the VISA-A score (r = 0.54 [0.26-0.76]). The discriminant validity was good with the ALR-RSI, which was significantly lower in the patients that did not return to sport: 60.7 (40-81.4) compared to those that did: 83.2 (64.3-100) p = 0.001. Reproducibility was excellent with an intra-class correlation coefficient ρ of 0.99 [097-1.00]. The internal consistency was excellent (alpha coefficient = 0.95). CONCLUSION: The ALR-RSI score provides a valid, reproducible assessment of the psychological readiness to return to sport in patients who undergo surgical Achilles tendon suture repair. LEVEL OF EVIDENCE: III.

Higher preoperative range of motion is predictive of good mid-term results in the surgical management of osteochondral lesions of the talus: a prospective multicentric study.

INTRODUCTION: Osteochondral lesions of the talus (OLT) are a frequent cause of pain in young patients and a new CT arthrographic classification system of OLT was recently proposed to help guide the choices of and standardize the indications for surgical treatment. The primary hypothesis was that this algorithm would result in a postoperative AOFAS score of ≥ 80/100. The secondary hypothesis was to identify the preoperative factors of successful surgery. METHODS: This was a prospective observational multicenter study. Eighty-six patients who underwent surgery for OLT after at least 6 months of unsuccessful conservative management were included for a mean follow-up of 15 months (12-36). Forty-nine patients with stage 1 OLT underwent microperforation, 2 patients with stage 2 OLT underwent a lift, drill, fill, and fix graft procedure with screw fixation, and 35 patients with stage 3 OLT were treated with mosaicplasty. RESULTS: After a follow-up of at least 1 year, 56 patients (65%) had an AOFAS score > 80 and the mean AOFAS score was 82 (16-100). A lower BMI (p = 0.038), a higher preoperative range of motion in the ankle (p = 0.033), higher preoperative AOFAS and FAOS scores (p = 0.001 and p = 0.011), and the presence of a preoperative bone bruise on MRI (p = 0.020) were good prognostic factors on univariate analysis. The presence of grade 1 osteoarthritis on the Van Dijk classification was predictive of a poor prognosis (p = 0.044). Multivariate analysis showed that a good preoperative range of motion (OR = 1.080 [1.020-1.150] p = 0.01) was predictive of a positive outcome, while grade 1 osteoarthritis was predictive of a poor outcome (OR = 0.147 [0.036-0.603] p = 0.008). The postoperative AOFAS decreased in six patients and 17 patients had at least one complication: six dysthesias of the superficial fibular nerve, two of the sural nerve, and nine stage 1 complex regional pain syndromes. CONCLUSION: The new algorithm for OLT resulted in a postoperative AOFAS score of ≥ 80/100 in 65% of cases. The positive predictive factors of a successful postoperative outcome were the presence of a good preoperative range of motion and the absence of preoperative osteoarthritis. LEVEL OF EVIDENCE: Level II.

Applicability of 'Toolkit for Safety Assessment' tool to interventional radiology using probabilistic risk assessment techniques.

Interventional radiology brings extensive benefits to patients. Nevertheless, certain procedures may result in high doses of radiation, leading to health risks to occupationally exposed individuals (OEIs). Therefore, a more comprehensive risk analysis is essential to ensuring safety and minimising radiation exposures for all OEIs. The Toolkit for Safety Assessment (TOKSA) tool performs risk assessments based on the concepts described in 'General Safety Requirements' Part 3 (Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards) and Part 4 (Safety Assessment for Facilities and Activities). This tool was developed based on the 'Ibero-American Forum of Radiological and Nuclear Regulatory Agencies' risk models and can promote the use of the risk assessment processes by OEIs. The aim of this study was to experimentally analyse the applicability of the TOKSA tool in interventional radiology with the use/support of probabilistic risk assessment techniques. The results were used to reduce the risks associated with a hemodynamics room in a hospital in Belo Horizonte, Brazil.

Machine learning-based prediction of insufficient contrast enhancement in coronary computed tomography angiography.

OBJECTIVES: Patient-tailored contrast delivery protocols strongly reduce the total iodine load and in general improve image quality in CT coronary angiography (CTCA). We aim to use machine learning to predict cases with insufficient contrast enhancement and to identify parameters with the highest predictive value. METHODS: Machine learning models were developed using data from 1,447 CTs. We included patient features, imaging settings, and test bolus features. The models were trained to predict CTCA images with a mean attenuation value in the ascending aorta below 400 HU. The accuracy was assessed by the area under the receiver operating characteristic (AUROC) and precision-recall curves (AUPRC). Shapley Additive exPlanations was used to assess the impact of features on the prediction of insufficient contrast enhancement. RESULTS: A total of 399 out of 1,447 scans revealed attenuation values in the ascending aorta below 400 HU. The best model trained using only patient features and CT settings achieved an AUROC of 0.78 (95% CI: 0.73-0.83) and AUPRC of 0.65 (95% CI: 0.58-0.71). With the inclusion of the test bolus features, it achieved an AUROC of 0.84 (95% CI: 0.81-0.87), an AUPRC of 0.71 (95% CI: 0.66-0.76), and a sensitivity of 0.66 and specificity of 0.88. The test bolus' peak height was the feature that impacted low attenuation prediction most. CONCLUSION: Prediction of insufficient contrast enhancement in CT coronary angiography scans can be achieved using machine learning models. Our experiments suggest that test bolus features are strongly predictive of low attenuation values and can be used to further improve patient-specific contrast delivery protocols. KEY POINTS: • Prediction of insufficient contrast enhancement in CT coronary angiography scans can be achieved using machine learning models. • The peak height of the test bolus curve is the most impacting feature for the best performing model.

Effects of stress exposure in captivity on physiology and infection in avian hosts: no evidence of increased Borrelia burgdorferi s.l. infectivity to vector ticks.

Exposure to environmental stressors, an increasingly recurring event in natural communities due to anthropogenic-induced environmental change, profoundly impacts disease emergence and spread. One mechanism through which this occurs is through stress-induced immunosuppression increasing disease susceptibility, prevalence, intensity and reactivation in hosts. We experimentally evaluated how exposure to stressors affected both the physiology of avian hosts and the prevalence of the zoonotic bacteria Borrelia burgdorferi sensu lato (s.l.), in two model species-the blackbird Turdus merula and the robin Erithacus rubecula captured in the wild, using xenodiagnoses and analysis of skin biopsies and blood. Although exposure to stressors in captivity induced physiological stress in birds (increased the number of circulating heterophils), there was no evidence of increased infectivity to xenodiagnostic ticks. However, Borrelia detection in the blood for both experimental groups of blackbirds was higher by the end of the captivity period. The infectivity and efficiency of transmission were higher for blackbirds than robins. When comparing different methodologies to determine infection status, xenodiagnosis was a more sensitive method than skin biopsies and blood samples, which could be attributed to mild levels of infection in these avian hosts and/or dynamics and timing of Borrelia infection relapses and redistribution in tissues.

Effects of postpartum milking strategy on plasma mineral concentrations and colostrum, transition milk, and milk yield and composition in multiparous dairy cows.

The effects of postpartum milking strategy on plasma mineral concentrations, blood ß-hydroxybutyrate (BHB) concentration, and colostrum, transition milk, and first monthly test milk yield and composition were evaluated in 90 multiparous Jersey and Jersey × Holstein crossbreed cows from a commercial farm. Before first postpartum milking, cows were randomly assigned to the following milking strategies, implemented during the first 2 d postpartum: twice-a-day milking (M2, standard industry practice, milking every 12 h; n = 22), once-a-day milking (M1, milking every 24 h; n = 24), restricted milking (MR, 3-L milking every 12 h; n = 21), and delayed milking (MD, no milking for the first 24 h, and milking every 12 h afterward; n = 23). Blood samples for total plasma Ca, P, and Mg determination were collected from enrollment every 4 h up to 48 h, and at 3 d in milk. Blood BHB concentration was determined at 3 and 11 d in milk. Colostrum and transition milk yields were recorded, and samples were collected at each study milking for IgG and somatic cell count (SCC) determinations. Information for first monthly test milk yield and composition was obtained from the Dairy Herd Improvement Association. Statistical analyses were conducted using generalized multiple linear and Poisson regressions with Dunnett adjustment and M2 as reference group for mean comparisons. Overall, plasma Ca concentration within 48 h after enrollment was higher for MD (2.17 mmol/L), tended to be higher for MR (2.15 mmol/L), and was similar for M1 (2.09 mmol/L) compared with M2 cows (2.06 mmol/L). No statistically significant differences compared with M2 cows were observed for plasma P and Mg concentrations. Colostrum and transition milk and total Ca harvested within 48 h after enrollment were lower for M1, MR, and MD compared with M2 cows. The MD strategy prevented harvesting colostrum with >50 g of IgG/L. No statistically significant effects were detected on plasma mineral concentrations at 3 DIM, blood BHB concentration, colostrum and transition milk SCC within 48 h after enrollment, or milk yield, energy-corrected milk yield, and SCC at first monthly test. Our results suggest that postpartum plasma Ca concentration may be influenced by postpartum milking strategy, without interfering with future milk yield and udder health. Further studies should evaluate whether the proposed milking strategies in early postpartum affect production, reproduction, or health.

Brief International Cognitive Assessment for Multiple Sclerosis scores are associated with the cortical thickness of specific cortical areas in relapsing-remitting patients.

BACKGROUND: Cognitive impairment is frequent and disabling in multiple sclerosis (MS). The Brief International Cognitive Assessment in MS (BICAMS) is a recent short battery usable in clinical practice for cognitive evaluation of MS patients. OBJECTIVE: To find cortical areas or brain volumes on magnetic resonance imaging (MRI) structural sequences associated with BICAMS scores in MS. METHODS: In this cross-sectional single-center study (NCT03656055, September 4, 2018), 96 relapsing remitting-MS patients under natalizumab and without recent clinical or radiological inflammation were included. Patients underwent brain MRI and the three BICAMS tests, evaluating information processing speed (SDMT), visuo-spatial memory (BVMT-R), and verbal memory (FVLT). RESULTS: Cortical thickness in the left frontal superior and the right precentral gyri was associated with BVMT-R scores whereas cortical thickness in the left Broca's area and the right superior temporal gyrus was associated with FVLT scores. We observed associations between white matter inflammatory lesions connected to these cortical regions and BICAMS subscores. CONCLUSIONS: BICAMS scores are associated with specific cortical areas, the cognitive domain matching the known functions of the cortical area. Specific cognitive impairments in MS may be associated with specific cortical regions, themselves influenced by white matter inflammatory lesions and demographical parameters (age, sex, education level).

Atomic Hong-Ou-Mandel experiment.

Two-particle interference is a fundamental feature of quantum mechanics, and is even less intuitive than wave-particle duality for a single particle. In this duality, classical concepts--wave or particle--are still referred to, and interference happens in ordinary space-time. On the other hand, two-particle interference takes place in a mathematical space that has no classical counterpart. Entanglement lies at the heart of this interference, as it does in the fundamental tests of quantum mechanics involving the violation of Bell's inequalities. The Hong, Ou and Mandel experiment is a conceptually simpler situation, in which the interference between two-photon amplitudes also leads to behaviour impossible to describe using a simple classical model. Here we report the realization of the Hong, Ou and Mandel experiment using atoms instead of photons. We create a source that emits pairs of atoms, and cause one atom of each pair to enter one of the two input channels of a beam-splitter, and the other atom to enter the other input channel. When the atoms are spatially overlapped so that the two inputs are indistinguishable, the atoms always emerge together in one of the output channels. This result opens the way to testing Bell's inequalities involving mechanical observables of massive particles, such as momentum, using methods inspired by quantum optics, and to testing theories of the quantum-to-classical transition. Our work also demonstrates a new way to benchmark non-classical atom sources that may be of interest for quantum information processing and quantum simulation.

Influence of ultraconservative access cavities on instrumentation efficacy with XP-endo Shaper and Reciproc, filling ability and load capacity of mandibular molars subjected to thermomechanical cycling.

AIM: To evaluate the influence of ultraconservative access cavities (UltraAC) on canal shaping and filling ability and load capacity of mandibular molars after root canal preparation with XP-endo Shaper (XP) or Reciproc (RC), under simulated clinical conditions. Traditional access cavities (TradAC) were used for comparison. METHODOLOGY: Forty extracted mandibular molars were scanned by micro-computed tomographic and, based on similar anatomical features, were divided into four groups (n = 10), according to the type of access cavity and canal instrumentation protocol: TradAC/RC, TradAC/XP, UltraAC/RC and UltraAC/XP. All root canal procedures were performed with the teeth placed in a dental mannequin. Teeth were scanned after root canal instrumentation and filling. Unprepared canal area, dentine removed, accumulated hard tissue debris (AHTD), canal transportation, presence of voids and filling material remnants within the pulp chamber were analysed. After restorative procedures, the teeth were subjected to thermomechanical cycling and to a load capacity test. Statistical analyses were performed using two-way anova test, considering the randomized blocks design (P < 0.05). RESULTS: The percentage of unprepared canal area was significantly lower in TradAC groups when compared to UltraAC groups (P < 0.05), regardless of the instrument used. The UltraAC/XP group had significantly lower percentage of root dentine removed when compared to other groups (P < 0.05). UltraAC/XP and TradAC/XP groups had significantly lower percentages of AHTD than UltraAC/RC and TradAC/RC groups (P < 0.05). Regarding canal transportation, in the MB root canals, the TradAC/XP group had significantly lower values than other groups (P < 0.05). In general, in ML and distal root canals, TradAC/XP and UltraAC/XP groups had significantly lower values of canal transportation when compared to other groups (P < 0.05). Moreover, the UltraAC/RC had the greatest canal transportation values in MB and distal canals. The UltraAC groups had significantly greater percentages of voids and volume of remaining root filling material within the pulp chamber after cleaning procedures than TradAC groups (P < 0.05). There was no difference in the load capacity amongst groups (P < 0.05). CONCLUSION: The UltraAC/XP and UltraAC/RC groups had significantly greater areas of unprepared canal walls, significantly more voids and volume of root filling material remnants within the pulp chamber after canal filling. UltraAC/XP was associated with significantly less root dentine removal and significantly more AHTD whilst TradAC/XP had overall significantly less canal transportation. No differences were observed in the load capacity amongst groups.

Preserving dentine in minimally invasive access cavities does not strength fracture resistance of restored mandibular molars.

AIM: To evaluate the correlation between the volume of dental hard tissues removed and the fracture resistance of mandibular molar teeth with ultraconservative (UltraAC) or traditional (TradAC) access cavity preparations. METHODOLOGY: Sixty recently extracted and intact mandibular first molars were scanned in a microcomputed tomographic (micro-CT) device, anatomically matched and assigned at random to 2 groups (n = 30), according to the access cavity type: UltraAC or TradAC. After access preparation, mesial and distal canals were prepared using Reciproc instruments and a new scan was taken. The volumes of pulp chamber and dental hard tissues in each specimen were measured before and after the experimental procedures, and the percentage volume reduction of hard tissues calculated for the entire tooth and for the crown separately. Teeth were then root filled, restored and subjected to fracture resistance tests in an universal testing machine. The force required to fracture was recorded in Newtons (N). The adherence of the variables to a Gaussian curve was verified using a Shapiro-Wilk test. Skewed data were analysed with nonparametric Wilcoxon signed rank or Spearman correlation tests, whilst the normally distributed data were analysed with a dependent samples Student t-test. Level of significance was set at 5%. RESULTS: Pre-operatively, no difference was observed between groups regarding the volume of pulp canal space or dental hard tissues (P > 0.05). After access preparation, volumes of the removed hard tissues from the entire tooth and from the crown were significantly greater in teeth prepared with TradAC than with UltraAC (P < 0.05). No significant difference was observed in the fracture resistance values between TradAC (902.9 ± 347.8 N) and UltraAC (948.7 ± 405.7 N) groups (P = 0.975). The Spearman test was unable to identify a correlation between fracture resistance and percentage volume of removed dental hard tissues in the entire root (P = 0.525, r = -0.084) or only in the crown (P = 0.152, r = -0.187). CONCLUSION: The volume of hard dental tissues removed, although greater in teeth with TradAC compared to UltraAC, did not correlate with the fracture resistance results, indicating that a minimally invasive access cavity did not increase the resistance of restored mandibular first molars to fracture.

Contrast-enhanced micro-CT to assess dental pulp tissue debridement in root canals of extracted teeth: a series of cascading experiments towards method validation.

AIM: To validate a new method for the evaluation of pulp tissue debridement in the root canals of extracted teeth using an impregnation protocol involving potassium triiodide, a radiocontrast solution known as Lugol's, combined with micro-computed tomographic (micro-CT) imaging. METHODOLOGY: The impact of NaOCl on the radiopacity of Lugol's solution was assessed using a two-fold dilution series of Lugol in distilled water and 5.25% NaOCl, which were then pipetted into transparent dishes and radiographed. To verify the influence of Lugol on the proteolytic effect of NaOCl, a dissolution test was performed using fresh bovine meat. Ten slices did not undergo any tissue processing, whilst twenty slices were fixed in formaldehyde for 24 h. After that, 10 of them were immersed in Lugol for another 24 h. Then, all specimens were placed in NaOCl and the time required for a complete tissue dissolution was recorded. For the last experiments (histological validation and micro-CT assessment), 8 extracted mandibular premolars with formerly vital pulps were immersed in buffered formalin, scanned in a micro-CT device, accessed, immersed in Lugol for 7 days and scanned again. Then, the root canals of 5 teeth were prepared and scanned, and the volume of remaining pulp tissue identified and quantified, whilst 3 teeth were histologically processed. The same specimens were subjected to histological assessment, and the images of the histologic sections were registered with the corresponding micro-CT images to verify whether the pulp tissue in the histological sections matched its counterpart in the Lugol-impregnated tissues identified in the micro-CT slices. RESULTS: There was no discernible effect on radiopacity when NaOCl was mixed with Lugol's solution. Tissue processing did not affect the time required for the complete dissolution of fresh bovine meat. Histological evaluation revealed a correlation between micro-CT and histological images confirming the identification of Lugol-impregnated pulp tissue in micro-CT images. CONCLUSIONS: The radiocontrast Lugol's solution was unaffected by NaOCl and did not interfere with its soft tissue dissolution capability. The impregnation protocol using Lugol's solution allowed the visualization of pulp tissue on the micro-CT images and the identification of pulp remnants after chemical-mechanical canal procedures.

Cardiac troponin is associated with cardiac outcomes in men and women with atrial fibrillation, insights from the ARISTOTLE trial.

BACKGROUND: Cardiac troponin T (cTnT) and I (cTnI) concentrations provide strong prognostic information in anticoagulated patients with atrial fibrillation (AF). Whether the associations between cardiac troponin concentrations and mortality and morbidity differ by sex is not known. OBJECTIVES: To assess whether men and women have different concentrations and prognostic value of cTnT and cTnI measurements in anticoagulated patients with AF. METHODS: cTnT and cTnI concentrations were measured with high-sensitivity (hs) assays in EDTA plasma samples obtained from the multicentre ARISTOTLE trial, which randomized patients with AF and at least one risk factor for stroke or systemic embolic event to warfarin or apixaban. Patients were stratified according to sex and the associations between hs-troponin concentrations, and all-cause death, cardiac death, myocardial infarction, stroke or systemic embolic event and major bleeding were assessed in multivariable regression models. RESULTS: We found higher cardiac troponin concentrations in men (n = 9649) compared to women (n = 5331), both for hs-cTnT (median 11.8 [Q1-3 8.1-18.0] vs. 9.6 [6.7-14.3] ng L-1 , P < 0.001) and hs-cTnI (5.8 [3.4-10.8] vs. 4.9 [3.1-8.8] ng L-1 , P < 0.001). Adjusting for baseline demographics, comorbidities and medications, men still had significantly higher hs-troponin concentrations than women. C-reactive protein and N-terminal pro-B-type natriuretic peptide concentrations were higher in female patients. Both hs-cTnT and hs-cTnI concentrations were associated with all clinical outcomes similarly in men and women (p-value for interaction >0.05 for all end-points). CONCLUSION: Men have higher hs-troponin concentrations than women in AF. Regardless of sex, hs-troponin concentrations remain similarly associated with adverse clinical outcomes in anticoagulated patients with AF.

Electrochemical dissolution of nickel-titanium instrument fragments in root canals of extracted human maxillary molars using a small reservoir of electrolyte.

AIM: To evaluate the viability of the electrochemical dissolution of fragments of fractured NiTi instruments in root canals of extracted human maxillary molars, using two electrodes and the solution restricted to a small reservoir coupled to the pulp chamber. The primary hypothesis was that this method enables the reduction of fragment volume and re-establishment of the root canal path with a size 08 K-file, both in simulated canals and in extracted human maxillary molars. METHODOLOGY: Fragments of F1 ProTaper instruments were polarized in simulated root canals and in distobuccal root canals of extracted maxillary molars using a new method, with the solution restricted to a small acrylic microcell coupled to each resin block or pulp chamber. Two electrodes were used, where one was kept in contact with the intracanal fragment and another was positioned in the solution present in the acrylic microcell. After the tests, a size 08 K-file was used passively to verify the possibility of bypassing the fragment, which was also confirmed by radiographic analysis. Micro-CT analysis of the teeth was used before and after fragment dissolution to evaluate the volume, length and porosity of the fragments. The D'Agostino-Pearson normality test was used to verify the distribution of the data. A paired t-test (P < 0.05) was used to compare the volume, length and porosity of the fragments before and after the dissolution tests. RESULTS: After dissolution, all fragments could be bypassed with a size 08 K-file in both simulated canals and in extracted teeth. The dissolution process did not result in significant reduction of neither the fragment length nor the fragment porosity. However, it resulted in a significant reduction of fragment volume (paired t-test, P < 0.05). CONCLUSION: The electrochemical dissolution of fragments of NiTi files in root canals of extracted human maxillary molars using two electrodes, and the solution restricted to a small reservoir coupled to the pulp chamber resulted in a significant reduction of fragment volume. The re-establishment of the root canal path with the passive insertion of size 08 K-files was possible in all samples after the tests, both in simulated canals and in extracted teeth.

Do pre-existing microcracks play a role in the fracture resistance of roots in a laboratory setting?

AIM: To investigate a potential cause-effect relationship between dentinal microcracks and fracture resistance of mandibular incisors that had not been endodontically treated. METHODOLOGY: Sixty mandibular incisors with circular-shaped canals were selected based on micro-computed tomographic scans to create a homogeneous sample. The cross-sectional images of the specimens were screened to identify and quantify the presence of dentinal microcracks. Then, teeth were embedded in polystyrene resin and subjected to axial compressive loading using a universal testing machine. After fracture, the roots were re-scanned and fractography analysis was performed by inspection of 3D models to verify crack propagation. Spearman's rank correlation was used to assess the correlation between the number of microcracks and force required to fracture. RESULTS: Dentinal microcracks were detected in 79% of the specimens (n = 44). The incidence of microcracks varied between teeth from 6% to 42% of the total slices per sample (average of 14 ± 17%). The number of microcracks per sample varied from 0 to 1605, with an average of 412 ± 484 (median = 221 and IQR 25% = 15/75% = 658). The load at failure values varied from 227 to 924 N, with an average of 560.3 ± 168.1 N (median = 561 and IQR 25% = 458/75% = 694). The Spearman correlation coefficient (rho) equalled 0.065. CONCLUSIONS: There was no cause-effect relationship between the number of dentinal microcracks and the fracture resistance of nonendodontically treated mandibular incisors. The presence and quantity of microcracks did not make these roots more prone to fracture.

The impact of minimally invasive root canal preparation strategies on the ability to shape root canals of mandibular molars.

AIM: To evaluate the use of a reduced taper endodontic instrument system (Bassi Logic™ .03 taper) and expandable heat-treated system (XP-endo Shaper) on the ability to shape canals in mandibular molars, by means of microcomputed tomography (micro-CT) analysis. The Reciproc system was used as the reference for comparison. METHODOLOGY: Twenty-four mandibular molars were scanned in a micro-CT, matched based on similar anatomical features and sorted into three groups (n = 8 per group), according to root canal preparation system: Bassi Logic™ .03, XP-endo Shaper and Reciproc. The teeth were mounted onto a mannequin and the pulp chambers were accessed with traditional access cavities. In Bassi Logic™ .03 and Reciproc groups, mesial canals were prepared with size 25, .03 taper or R25 (size 25, .08v taper) instruments and the distal root canal with size 25, .03 taper and size 40, .03 taper or R25 and R40 (size 40, .06v taper), respectively. In XP-endo Shaper groups, all root canals were prepared with XP-endo Shaper (size 30, .04v taper). After root canal preparation, the teeth were rescanned. The percentage of untouched canal areas and the percentage of removed dentine were evaluated separately for mesial and distal root canals. The data were analysed using one-way anova and Tukey tests (P < 0.05). RESULTS: The Bassi Logic™ .03 group was associated with a greater percentage of untouched canal areas when compared to XP-endo Shaper and Reciproc groups for mesial and distal root canals (P < 0.05), but no differences were found between XP-endo Shaper and Reciproc groups (P > 0.05). No significant difference was observed in the percentage of dentine removed amongst the groups for mesial and distal root canals (P > 0.05). CONCLUSION: The use of a reduced taper system (Bassi Logic™ .03) during root canal preparation resulted in a greater percentage of untouched canal areas when compared to XP-endo Shaper and Reciproc instruments. No differences were observed amongst the systems regarding the percentage of dentine removed.

Does ultraconservative access affect the efficacy of root canal treatment and the fracture resistance of two-rooted maxillary premolars?

AIM: To evaluate the influence of ultraconservative endodontic cavities (UEC) on canal shaping and filling ability, cleaning of the pulp chamber, time required to perform root canal treatment and fracture resistance of 2-rooted maxillary premolars in comparison with traditional endodontic access cavities (TEC) in extracted teeth placed in a phantom head to simulate clinical conditions. METHODOLOGY: Twenty extracted intact 2-rooted maxillary premolars were scanned in a micro-computed tomographic device, matched based on similar anatomical features of the canals and assigned to UEC or TEC groups (n = 10). Then, teeth were mounted on a mannequin head and their pulp chamber accessed. After canal preparation, filling and cavity restoration, the time required to perform root canal treatment was recorded and the specimens were loaded to fracture in a universal testing machine. The maximum load at fracture was recorded. The sample was scanned after root canal instrumentation, filling and restoration procedures. Untouched canal areas, accumulation of hard-tissue debris (AHTD), voids in root fillings and cleaning of the pulp chamber were analysed. Data were analysed statistically using Shapiro-Wilk and Student's t-tests with a significance level of 5%. RESULTS: The percentage of untouched canal area did not differ significantly between UEC and TEC groups (P > 0.05). However, UECs were associated with a greater percentage of AHTD after canal preparation (P < 0.05). No differences were observed in terms of voids in root fillings between the groups (P > 0.05). Nonetheless, UEC had a greater percentage of root filling remnants in the pulp chamber after cleaning procedures (P < 0.05). The time required to perform root canal treatment was significantly longer in the UEC group (P < 0.05). There was no difference regarding the mean load at fracture between the groups (P > 0.05). Unrestorable fractures were observed in all specimens of both groups. CONCLUSIONS: There was no true benefit associated with ultraconservative endodontic cavities. UEC resulted in more AHTD remaining inside the root canals. UEC did not influence the quality of root fillings; however, UEC made the cleaning procedure of the pulp chamber more difficult, thus increasing the total time required to perform root canal treatment. Moreover, UEC were not associated with an increase in fracture resistance of root filled 2-rooted maxillary premolars.

Arrowhead design ultrasonic tip as a supplementary tool for canal debridement.

AIM: To investigate the shaping and cleaning performance of the Clearsonic ultrasonic tip as a supplementary tool during the preparation of long oval-shaped root canals through micro-computed tomographic (micro-CT) imaging technology. The Reciproc M-Wire R40 instrument was used as a reference instrumentation technique for comparison. METHODOLOGY: Twenty mandibular incisors with single, straight and long oval-shaped canals were selected and pair-matched by micro-CT scanning. The root canals were prepared with Reciproc R25 and R40 instruments, scanned again in a micro-CT device and randomly allocated into one of the two experimental groups (n = 10), according to the supplementary debridement protocol used: Clearsonic or Reciproc R40 used in a brushing motion against buccal and lingual walls. Noninstrumented canal areas, accumulation of hard-tissue debris (AHTD) and volume of removed dentine were assessed using micro-CT imaging following the supplementary debridement protocols. Data were analysed statistically in two phases using a t-test with a significance level of 5%. RESULTS: In phase-1, there was a significant similarity between the samples regarding the evaluated micro-CT baseline parameters (P > 0.05), validating the anatomical similarity between the tooth pairs. In phase-2, there was a significant difference between the groups for canal volume, surface area, noninstrumented root canal walls and the amount of removed dentine for both absolute and percentage values (P < 0.05), but not for AHTD (P = 0.759). CONCLUSIONS: The Clearsonic tip outperformed the Reciproc R40 instrument as a supplementary debridement protocol as it was associated with significantly greater reduction of noninstrumented root canals walls and consequently a larger amount of removed dentine. Both groups performed similarly regarding the AHTD.

Dentinal microcracks on freshly extracted teeth: the impact of the extraction technique.

AIM: To evaluate the incidence of root dentinal microcracks after two extraction techniques through micro-computed tomographic (micro-CT) analysis. METHODOLOGY: Thirty pairs of premolars, extracted for orthodontic reasons, were assigned to two experimental groups, following a split-mouth design (n = 30): traumatic technique group (TTG) - teeth extracted following a conventional protocol using forceps, and an atraumatic technique group (ATG) - teeth extracted following an atraumatic technique protocol in which the root was gently detached from the periodontal ligament using a periotome. All teeth were immediately immersed in distilled water and scanned in a micro-CT device within 72 h following the extraction. The assessment of the images was completed on cross-section images by two masked evaluators. The Mann-Whitney test was used to assess the significant differences between the groups regarding the number of cross-sections displaying microcracks whilst the Fischer's exact test was used to assess differences in the frequency of specimens with defects (P < 0.05). RESULTS: A total of 52 750 micro-CT cross-sectional images were evaluated. A total of 352 cross-sections had at least one dentinal defect. Microcracks were observed in five teeth of the TTG group (n = 352 slices) and in two teeth of the ATG group (n = 103 slices). The statistical analysis used was unable to detect a significant difference between the groups in terms of the number of dentinal microcracks (P = 0.233) and in the frequency of teeth displaying microcracks (P = 0.424). CONCLUSION: A small number of sound teeth without endodontic treatment had dentinal microcracks regardless of the extraction technique applied. No difference was noticed between the traumatic and atraumatic techniques in the incidence of microcracks.

A nonconventional two-stage fermentation system for the production of aerial conidia of entomopathogenic fungi utilizing surface tension.

AIM: To describe a new approach in which production of conidia of an entomopathogenic fungus takes place on the surface of an unstirred shallow liquid culture kept in nonabsorbent wells distributed in plastic sheets resembling a honeycomb. METHODS AND RESULTS: First, liquid incubation time and medium composition for production of Beauveria bassiana aerial conidia were optimized. Wells inoculated with Sabouraud dextrose yeast extract produced 2·2 × 108 conidia per cm2 of liquid surface following 5 days of incubation. Finally, tests were carried out in a prototype comprised of stacked plastic sheets in a cylindrical container. Conidia production on liquid culture surface varied from 1·2 to 1·6 × 109 conidia per ml of fermented broth. Germination rates and insect activity towards Tenebrio molitor larvae were not negatively affected when compared to conidia produced on solid medium. CONCLUSIONS: The two-stage fermentation process here described, based on a simple nonabsorbent inert support, has potential for the application in the production of aerial conidia of B. bassiana and other fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: Aerial conidia are the most extensive propagule type used in commercial mycopesticides, traditionally produced by solid-state fermentation (SSF). The industrial applications and other important benefits of the two-stage fermentation process here described may overcome some hurdles inherent to SSF aiming for the production of aerial conidia. Additionally, production consistency is increased by the use of chemically defined medium, and the better control of the environmental conditions could allow for more reproducible industrial batches.