An in vitro evaluation of the WIRELE-x electronic apex locator.

This study evaluated the accuracy of the Wirele-X (Forum Tec, Ashkelon, Israel), a novel Bluetooth-enabled wireless electronic apex locator. Thirty-one extracted teeth with mature apices were used. Under 10X magnification, the actual canal lengths were determined. The teeth were embedded in alginate and electronic canal lengths were obtained using the Root ZX II and Wirele-X electronic apex locators. The actual canal lengths and electronic canal lengths were compared with Student's t-test. The average distance from the file tip to the actual canal length was -0.11 mm (±0.16) for the Root ZX II, and - 0.07 mm (±0.21) for the Wirele-X. There were no statistically significant differences between the two electronic apex locators in their ability to determine the actual canal length (p > 0.05). The wireless apex locator (Wirele-X) and the wired apex locator (Root ZX II) were found to be equally accurate.

The Influence of Cone Beam Computed Tomography-Derived 3D-Printed Models on Endodontic Microsurgical Treatment Planning and Confidence of the Operator.

INTRODUCTION: Currently, there are no studies evaluating the impact of 3-dimensional (3D) printed models on endodontic surgical treatment planning. The aims of this study were: 1) to determine if 3D models could influence treatment planning; and 2) to assess the effect of 3D supported planning on operator confidence. MATERIALS: Endodontic practitioners (n = 25) were asked to analyze a preselected cone beam computed tomography (CBCT) scan of an endodontic surgical case and answer a questionnaire that elucidated their surgical approach. After 30 days, the same participants were asked to analyze the same CBCT scan. Additionally, participants were asked to study and to perform a mock osteotomy on a 3D printed model. The participants responded to the same questionnaire along with a new set of questions. Responses were statistically analyzed using chi square test followed by either logistic or ordered regression analysis. Adjustment for multiple comparison analysis was done using a Bonferroni correction. Statistical significance was set at ≤0.005. RESULTS: The availability of both the 3D printed model and the CBCT scan resulted in statistically significant differences in the participants' responses to their ability to detect bone landmarks, predict the location of osteotomy, and to determine the following: size of osteotomy, angle of instrumentation, involvement of critical structures in flap reflection and involvement of vital structures during curettage. In addition, the participants' confidence in performing surgery was found to be significantly higher. CONCLUSIONS: The availability of 3D printed models did not alter the participants' surgical approach but it significantly improved their confidence for endodontic microsurgery.

Accuracy of the KontrolFlex AccuFile when used with the Root ZX electronic apex locator in vitro.

The aims of this study were to determine the efficacy of the KontrolFlex™ Accufile™ compared to the READY•STEEL™ Flexofile® using an electronic apex locator and to evaluate the instrument's design via scanning electron microscopy. Actual canal lengths of 30 extracted teeth were determined under magnification. An alginate model was used to determine experimental canal lengths with the Root ZX II apex locator (EAL) and size #10 Accufiles and Flexofiles. Differences between actual lengths and experimental lengths were compared with Student's t test. The average experimental lengths were short of the actual length by -0.10 mm (±0.34) and -0.12 mm (±0.16) for the Accufile and Flexofile, respectively with no statistical difference (p > 0.05). SEM images revealed similar non-cutting Batt tips and a square cross-section for the Accufile and triangular for the Flexofile. Both files provided similarly high levels of reliability when used with the Root ZX II EAL.

The micro-architecture of mitochondria at active zones: electron tomography reveals novel anchoring scaffolds and cristae structured for high-rate metabolism.

Mitochondria are integral elements of many nerve terminals. They must be appropriately positioned to regulate microdomains of Ca(2+) concentration and metabolic demand, but structures that anchor them in place have not been described. By applying the high resolution of electron tomography (ET) to the study of a central terminal, the calyx of Held, we revealed an elaborate cytoskeletal superstructure that connected a subset of mitochondria to the presynaptic membrane near active zones. This cytoskeletal network extended laterally and was well integrated into the nerve terminal cytoskeleton, which included filamentous linkages among synaptic vesicles. ET revealed novel features of inner membrane for these mitochondria. Crista structure was polarized in that crista junctions, circular openings of the inner membrane under the outer membrane, were aligned with the cytoskeletal superstructure and occurred at higher density in mitochondrial membrane facing the presynaptic membrane. These characteristics represent the first instance where a subcomponent of an organelle is shown to have a specific orientation relative to the polarized structure of a cell. The ratio of cristae to outer membrane surface area is large in these mitochondria relative to other tissues, indicating a high metabolic capacity. These observations suggest general principles for cytoskeletal anchoring of mitochondria in all tissues, reveal potential routes for nonsynaptic communication between presynaptic and postsynaptic partners using this novel cytoskeletal framework, and indicate that crista structure can be specialized for particular functions within cellular microdomains.

A survey of current trends in root canal treatment: access cavity design and cleaning and shaping practices.

The purpose of this study was to evaluate current trends in access cavity design and cleaning and shaping among endodontists. A survey was e-mailed to active members of the American Association of Endodontists. Data showed that most respondents used traditional (57%) or conservative (43%) access cavities; less than 1% reported using ultraconservative access cavities. A glide path was created by 93% of respondents; NaOCl was used as lubricant by 51% of respondents, while 28% used RC Prep, 9% used liquid EDTA, 7% used Glyde, and 2% did not use any lubricant. Most respondents used NaOCl at 5.25% or higher concentration. Smear layer was removed by 92% of endodontists. Apical gauging was mostly accomplished with hand files. Clinical preferences varied among surveyed endodontists and among different age groups. Currently, very few endodontists use ultraconservative access preparations. There was large variation among the respondents suggesting a possible need for quality guidelines.

Evaluation of Dental Students' Skills Acquisition in Endodontics Using a 3D Printed Tooth Model.

OBJECTIVE: The purpose of this prospective quantitative study was to assess the improvement of skills among pre-clinical dental students who practiced root canal obturation on a 3D-printed tooth model. METHODS: Preclinical students at the dental school (n=145) enrolled in the 2-week endodontic rotation course were invited to participate in the study. Four alphabetically distributed intact groups of first-year students were randomly allocated to either the control or the experimental group that obturated canals of a 3D-printed tooth. The plastic model was obtained from a microCT scan and based on an STL data set. The model was an identical replica of a natural mandibular molar that had been instrumented, ready for obturation. The control group did not obturate the tooth model but received identical instruction. Later in the course all students obturated an extracted human mandibular molar tooth. Technical obturation quality was assessed by two blinded evaluators. Radiographs were used to evaluate obturation length and density. Inter-observer reliability of average performance scores was calculated with the intra-class correlation coefficient for both consistency and absolute agreement. Obturation skills of those who practiced with the model were statistically compared to students who did not use the model with the Mann-Whitney U-test. RESULTS: Inter-observer reliability was very high for both consistency and absolute agreement. No significant differences were found in obturation skills between the experimental and control group (P>0.05). CONCLUSION: Under the condition of this study, dental students' obturation skills did not significantly improve by further practicing obturation using a 3D-printed model.

Current Trends in Use and Reuse of Nickel-Titanium Engine-driven Instruments: A Survey of Endodontists in the United States.

INTRODUCTION: Information is scarce regarding current usage practices of nickel-titanium (NiTi) engine-driven instruments in clinical practice. Therefore, the specific purpose of this survey was to assess trends among endodontists regarding the use and reuse of NiTi instruments. METHODS: A 16-question survey was sent by e-mail to about 4000 active members of the American Association of Endodontists. Data were collected over a 6-month period and compared using chi-square tests. RESULTS: A total of 957 surveys were collected (response rate = 23%). Of the respondents, 40.2% worked in solo practices; among them, there were significantly fewer recent graduates (<10 years) compared with those who graduated more than 10 years ago. Furthermore, 41.7% were in a group practice, 4.3% in corporate practice, 10.7% in university settings, and 3% in the military. Overall, 98.3% of respondents reported using NiTi instruments. Respondents who graduated less than 25 years ago use NiTi instruments significantly more (99%) than those who graduated more than 25 years ago (92.6%). Although 22.9% of respondents buy presterilized instruments, 41.6% sterilize them before use, and 35.5% do not sterilize new instruments before use; dental officers in the military reported that they use sterile new instruments in 100% of cases. NiTi instruments were reused by 74% of respondents. The 2 largest segments of the specialist endodontic instrument market belonged to Dentsply (York, PA; 56.9%) and EdgeEndo (Albuquerque, NM; 28.8%). CONCLUSIONS: There are significant differences in the use of NiTi instruments among types of practice and years since graduation. There were noticeable changes compared with findings reported about 10 years ago.

Feasibility of Nurse-Led Multidimensional Outcome Assessments in the Neuroscience Intensive Care Unit.

BACKGROUND: The outcome focus for survivors of critical care has shifted from mortality to patient-centered outcomes. Multidimensional outcome assessments performed in critically ill patients typically exclude those with primary neurological injuries. OBJECTIVE: To determine the feasibility of measurements of physical function, cognition, and quality of life in patients requiring neurocritical care. METHODS: This evaluation of a quality improvement initiative involved all patients admitted to the neuroscience intensive care unit at the University of Cincinnati Medical Center. INTERVENTIONS: Telephone assessments of physical function (Glasgow Outcome Scale-Extended and modified Rankin Scale scores), cognition (modified Telephone Interview for Cognitive Status), and quality of life (5-level EQ-5D) were conducted between 3 and 6 months after admission. RESULTS: During the 2-week pilot phase, the authors contacted and completed data entry for all patients admitted to the neuroscience intensive care unit over a 2-week period in approximately 11 hours. During the 18-month implementation phase, the authors followed 1324 patients at a mean (SD) time of 4.4 (0.8) months after admission. Mortality at follow-up was 38.9%; 74.8% of these patients underwent withdrawal of care. The overall loss to follow-up rate was 23.6%. Among all patients contacted, 94% were available by the second attempt to interview them by telephone. CONCLUSIONS: Obtaining multidimensional outcome assessments by telephone across a diverse population of neurocritically ill patients was feasible and efficient. The sample was similar to those in other cohort studies in the neurocritical care population, and the loss to follow-up rate was comparable with that of the general critical care population.

tappAS: a comprehensive computational framework for the analysis of the functional impact of differential splicing.

Recent advances in long-read sequencing solve inaccuracies in alternative transcript identification of full-length transcripts in short-read RNA-Seq data, which encourages the development of methods for isoform-centered functional analysis. Here, we present tappAS, the first framework to enable a comprehensive Functional Iso-Transcriptomics (FIT) analysis, which is effective at revealing the functional impact of context-specific post-transcriptional regulation. tappAS uses isoform-resolved annotation of coding and non-coding functional domains, motifs, and sites, in combination with novel analysis methods to interrogate different aspects of the functional readout of transcript variants and isoform regulation. tappAS software and documentation are available at https://app.tappas.org.

Resistance to cyclic fatigue of reciprocating instruments determined at body temperature and phase transformation analysis.

The purpose of this study was to compare cyclic fatigue (CF) resistance of reciprocating instruments at body temperature and relate the findings to their martensitic transformation temperatures. Contemporary nickel-titanium (NiTi) reciprocating instruments WaveOne Primary, WaveOne Gold Primary and EdgeFile X1 (n = 20 each and #25 tip diameter) were tested for CF resistance at body temperature (37 ± 1°C). Instruments were actioned according to manufacturer guidelines until fracture occurred in a simulated canal (angle of curvature = 60°, radius of curvature = 3 mm and centre of curvature = 5 mm from the tip). Time to fracture was recorded, and data analysed using Weibull analysis. Two instruments of each were tested using differential scanning calorimetry (DSC) to assess phase transformation temperatures. Reciprocating instruments manufactured with new alloys seem to be safer to CF than those manufactured with traditional M-Wire at body temperature. Martensitic transformation temperatures seem not to relate with fatigue behaviour for reciprocating motions.

Detecting Dentinal Microcracks Using Different Preparation Techniques: An In Situ Study with Cadaver Mandibles.

INTRODUCTION: This study assessed the frequency of dentinal microcracks using a cadaver mandible model in teeth instrumented with TRUShape (TS; Dentsply Sirona, York, PA), WaveOne Gold (WO, Dentsply Sirona), or K-files (KF) compared with an uninstrumented control group (CG). METHODS: Fifteen human mandibles with 95 single-rooted teeth were randomly distributed into the following groups: CG (no preparation, n = 11), TS (n = 28), WO (n = 28), and KF (step-back preparation with K-Flex-o-files [Dentsply Sirona], n = 28). Teeth were prepared to apical sizes of #25/.06 or #25/.07; overlying bone was removed, and then teeth were lifted out of the socket and sectioned at 3, 6, and 9 mm from the apex using a low-speed saw. Resulting slices were photographed at 20× and 25× magnification. Three independent and blinded evaluators assessed the images for the presence of dentinal microcracks and their extension, direction, and location. The chi-square test was used for statistical analysis (P < .05). RESULTS: In the final sample of 83 teeth for the 4 groups, microcracks were found in 10 of 33, 13 of 66, 16 of 69, and 21 of 81 sections for CG, TS, WO, and KF, respectively. There were no significant differences in the frequency of microcracks among the CG, TS, WO, or KF instruments overall or when comparing section levels (3 mm [P = .9], 6 mm [P = .18], or 9 mm [P = .69], respectively, from the apex). There were also no significant differences in the extension, direction, or location of the dentinal microcracks among all groups (P > .05). CONCLUSIONS: There was no difference in the frequency of microcracks among the experimental groups instrumented with TS, WO, and KF or uninstrumented controls.

Educational Outcomes of Small-Group Discussion Versus Traditional Lecture Format in Dental Students' Learning and Skills Acquisition.

The aim of this prospective quantitative study was to compare the effect of different instructional formats on dental students' skills and knowledge acquisition for access cavity preparation. All first-year dental students were invited to participate in this study conducted during the four consecutive two-week endodontic rotation courses at the University of the Pacific Arthur A. Dugoni School of Dentistry in spring semester 2015. Four alphabetically distributed intact groups of students were randomly allocated to two groups (n=70 each) that participated in either small-group discussion or a traditional lecture on access preparation. The first outcome measure was skill acquisition, measured by the quality of access cavities prepared in extracted teeth at the conclusion of the session. Two blinded raters scored direct observations on a continuous scale. Knowledge, the second outcome measure, was scored with a multiple-choice and open-ended question test at the end of each two-week session. Data were obtained for 134 of the 140 students, for a 96% response rate. The results showed that students in the small-group discussion groups scored significantly higher than those in the lecture groups when skill performance was tested (p=8.9 × 10(-7)). However, no significant differences were found in the acquisition of knowledge between the two groups on the written test. Active student participation was significantly related to improved manual skill acquisition, but the format of the session does not seem to have had a direct influence on acquired knowledge.

Microbiome shifts and the inhibition of quorum sensing by Black Band Disease cyanobacteria.

Disruption of the microbiome often correlates with the appearance of disease symptoms in metaorganisms such as corals. In Black Band Disease (BBD), a polymicrobial disease consortium dominated by the filamentous cyanobacterium Roseofilum reptotaenium displaces members of the epibiotic microbiome. We examined both normal surface microbiomes and BBD consortia on Caribbean corals and found that the microbiomes of healthy corals were dominated by Gammaproteobacteria, in particular Halomonas spp., and were remarkably stable across spatial and temporal scales. In contrast, the microbial community structure in black band consortia was more variable and more diverse. Nevertheless, deep sequencing revealed that members of the disease consortium were present in every sampled surface microbiome of Montastraea, Orbicella and Pseudodiploria corals, regardless of the health status. Within the BBD consortium, we identified lyngbic acid, a cyanobacterial secondary metabolite. It strongly inhibited quorum sensing (QS) in the Vibrio harveyi QS reporters. The effects of lyngbic acid on the QS reporters depended on the presence of the CAI-1 receptor CqsS. Lyngbic acid inhibited luminescence in native coral Vibrio spp. that also possess the CAI-1-mediated QS. The effects of this naturally occurring QS inhibitor on bacterial regulatory networks potentially contribute to the structuring of the interactions within BBD consortia.