Dietary patterns are related to cognitive functioning in elderly enriched with individuals at increased risk for Alzheimer's disease.

PURPOSE: To investigate cross-sectional associations between dietary patterns and cognitive functioning in elderly free of dementia. METHODS: Data of 389 participants from the German DELCODE study (52% female, 69 ± 6 years, mean Mini Mental State Score 29 ± 1) were included. The sample was enriched with elderly at increased risk for Alzheimer's disease (AD) by including participants with subjective cognitive decline, mild cognitive impairment (MCI) and siblings of AD patients. Mediterranean and MIND diets were derived from 148 Food Frequency Questionnaire items, and data-driven patterns by principal component analysis (PCA) of 39 food groups. Associations between dietary patterns and five cognitive domain scores were analyzed with linear regression analyses adjusted for demographics (model 1), and additionally for energy intake, BMI, other lifestyle variables and APOe4-status (model 2). For PCA-derived dietary components, final model 3 included all other dietary components. RESULTS: In fully adjusted models, adherence to Mediterranean and MIND diet was associated with better memory. The 'alcoholic beverages' PCA component was positively associated with most cognitive domains. Exclusion of MCI subjects (n = 60) revealed that Mediterranean and MIND diet were also related to language functions; associations with the alcoholic beverages component were attenuated, but most remained significant. CONCLUSION: In line with data from elderly population samples, Mediterranean and MIND diet and some data-derived dietary patterns were related to memory and language function. Longitudinal data are needed to draw conclusions on the putative effect of nutrition on the rate of cognitive decline, and on the potential of dietary interventions in groups at increased risk for AD.

What is of interest in Endodontology? A bibliometric review of research published in the International Endodontic Journal and the Journal of Endodontics from 1980 to 2019.

AIM: To report the most common terminology used in titles of scientific papers published in the International Endodontic Journal (IEJ) and Journal of Endodontics (JOE) between 1980 and 2019 and to identify the most-cited papers in these journals. METHODOLOGY: The Web of Science database was searched to retrieve all the manuscripts published in the IEJ and JOE between 1980 and 2019. The articles were analysed using the VOS viewer software and the terms within the titles extracted. The top-10 terms were categorized according to the number of occurrences and the decade of publication. Maps were created using the text data for each decade of publication. Classic papers were identified when the number of citations was >400. During the same period of time, highly cited studies were identified including the authors, institutions and countries associated with these papers. RESULTS: Terms such as canal, molar and periapical lesion were the most commonly used in titles between 1980 and 1999. The terms instruments, expression, case report and cell were the most often terms used between 2000 and 2019. During the last 10 years, an increase in the number of reviews and papers on cone beam computed tomography occurred. The organizations with the largest number of citations in each decade were University of São Paulo, University College London, Loma Linda University and United States Army. The country with the largest number of citations and greatest number of top 10 and top 100 manuscripts was the United States. A paper had to be associated with more than 167 citations to be included in the top-100 most-cited list; at least 14 papers met the criteria to be categorized as a citation classic (>400 citations). CONCLUSION: While many diverse areas of endodontics have been explored in the last 40 years within the IEJ and JOE, only a relatively few topics are highly cited and can be considered as classics.

Methods for measurement of root canal curvature: a systematic and critical review.

The assessment of root canal curvature is essential for clinical and research purposes. This systematic review presents an overview of the published techniques for the measurement of root canal curvature features using imaging and to provide a critique of their clinical application. A database search in PubMed, PubMed Central, Embase, Scopus, EBSCO Dentistry & Oral Sciences Source and Virtual Health Library was conducted, using appropriate key words to identify measurement methods for root canal curvatures. The search strategy retrieved 10594 records in total, and 31 records fulfilled the inclusion criteria. From 2D image acquisitions, eleven studies measured exclusively the angle of curvature, an additional thirteen measured other curvature features (level, height, radius, length and shape). Seven reports described methods from 3D imaging (CBCT, µCT). Root canal curvatures should be measured, for clinical proposes, to facilitate endodontic treatment planning, and in research, to reduce the risk of selection bias. This review has revealed that there are many methods described in the literature; however, no consensus exists on which method should be used. Some of the methodologies have potential clinical translation, whereas others are suitable for research purpose only, as they require a specific software or radiographic exposure in the mesiodistal direction.

A protocol for developing reporting guidelines for laboratory studies in Endodontology.

Laboratory-based research studies are the most common form of research endeavour and make up the majority of manuscripts that are submitted for publication in the field of Endodontology. The scientific information derived from laboratory studies can be used to design a wide range of subsequent studies and clinical trials and may have translational potential to benefit clinical practice. Unfortunately, the majority of laboratory-based articles submitted for publication fail the peer-review step, because unacceptable flaws or substantial limitations are identified. Even when apparently well-conducted laboratory-based articles are peer-reviewed, they can often require substantial corrections prior to the publication. It is apparent that some authors and reviewers may lack the training and experience to have developed a systematic approach to evaluate the quality of laboratory studies. Occasionally, even accepted manuscripts contain limitations that may compromise interpretation of data. To help authors avoid manuscript rejection and correction pitfalls, and to aid editors/reviewers to evaluate manuscripts systematically, the purpose of this project is to establish and publish quality guidelines for authors to report laboratory studies in the field of Endodontology so that the highest standards are achieved. The new guidelines will be named-'Preferred Reporting Items for Laboratory studies in Endodontology' (PRILE). A steering committee was assembled by the project leads to develop the guidelines through a five-phase consensus process. The committee will identify new items as well as review and adapt items from existing guidelines. The items forming the draft guidelines will be reviewed and refined by a PRILE Delphi Group (PDG). The items will be evaluated by the PDG on a nine-point Likert scale for relevance and inclusion. The agreed items will then be discussed by a PRILE face-to-face consensus meeting group (PFCMG) formed by 20 individuals to further refine the guidelines. This will be subject to final approval by the steering committee. The approved PRILE guidelines will be disseminated through publication in relevant journals, presented at congresses/meetings, and be freely available on a dedicated website. Feedback and comments will be solicited from researchers, editors and peer reviewers, who are invited to contact the steering committee with comments to help them update the guidelines periodically.

Genome-wide significant risk factors for Alzheimer's disease: role in progression to dementia due to Alzheimer's disease among subjects with mild cognitive impairment.

Few data are available concerning the role of risk markers for Alzheimer's disease (AD) in progression to AD dementia among subjects with mild cognitive impairment (MCI). We therefore investigated the role of well-known AD-associated single-nucleotide polymorphism (SNP) in the progression from MCI to AD dementia. Four independent MCI data sets were included in the analysis: (a) the German study on Aging, Cognition and Dementia in primary care patients (n=853); (b) the German Dementia Competence Network (n=812); (c) the Fundació ACE from Barcelona, Spain (n=1245); and (d) the MCI data set of the Amsterdam Dementia Cohort (n=306). The effects of single markers and combined polygenic scores were measured using Cox proportional hazards models and meta-analyses. The clusterin (CLU) locus was an independent genetic risk factor for MCI to AD progression (CLU rs9331888: hazard ratio (HR)=1.187 (1.054-1.32); P=0.0035). A polygenic score (PGS1) comprising nine established genome-wide AD risk loci predicted a small effect on the risk of MCI to AD progression in APOE-ɛ4 (apolipoprotein E-ɛ4) carriers (HR=1.746 (1.029-2.965); P=0.038). The novel AD loci reported by the International Genomics of Alzheimer's Project were not implicated in MCI to AD dementia progression. SNP-based polygenic risk scores comprising currently available AD genetic markers did not predict MCI to AD progression. We conclude that SNPs in CLU are potential markers for MCI to AD progression.

Lateral and axial cutting efficiency of instruments manufactured with conventional nickel-titanium and novel gold metallurgy.

AIM: To isolate the effect of metallurgy in lateral and axial cutting efficacy against plastic and bovine dentine substrates by comparing two rotary systems with identical design but manufactured with either conventional nickel-titanium or heat-treated gold alloy. METHODOLOGY: A total of 258 ProTaper Universal (PTU) and ProTaper Gold (PTG) Shaping instruments were used. Bending behaviour was assessed to determine the appropriate displacement associated with a 2 N force in lateral cutting. Ten instruments of each type were used in lateral action for 60 s against bovine dentine or plastic substrates four consecutive times producing four notches in each specimen. Ten further instruments of each type were used in on axial action in four standardized simulated root canals fabricated from 4-mm thick plastic or dentine discs. Both tests were performed at 300 rpm in a computer-controlled testing platform. Notch area and torsional load were compared with Student's t-tests. Repeated measures ANOVA was used to compare cutting efficiency across the four different time-points. Pearson correlation coefficients between substrates were also determined. RESULTS: For lateral action, all three PTG instruments cut significantly more effectively (P < 0.05) than PTU on the plastic substrate. S1 and S2 PTG cut significantly more after 120 and 180 s (P < 0.05) on bovine dentine substrate. For axial action, S1 and S2 PTG were significantly more efficient in cutting at 180 s on plastic and 120 s on bovine dentine (P < 0.05). CONCLUSION: Instruments made from heat-treated nickel-titanium gold alloy had equal or greater cutting efficiency when compared to those made from conventional nickel-titanium.

Association of manual or engine-driven glide path preparation with canal centring and apical transportation: a systematic review.

The role and effect of glide path preparation in root canal treatment remain controversial. This systematic review aims to compare apical transportation and canal centring of different glide path preparation techniques, with or without subsequent engine-driven root canal preparation. A database search in PubMed, PubMed Central, Embase, Scopus, EBSCO Dentistry & Oral Sciences Source and Virtual Health Library was conducted, using appropriate key words to identify the effect of glide path preparation (or its absence) on apical transportation and canal centring. An assessment for the risk of bias in included studies was carried out. Amongst 2146 studies, 18 satisfied the inclusion criteria. Nine studies assessed glide path preparation per se, comparing apical transportation and canal centring of rotary systems and/or manual files; eleven further investigations examined the efficacy of the glide path prior to final canal preparation with different engine-driven systems. Risk of bias and other study design features with potential influence on study outcomes and clinical implications were assessed. Based on the available evidence, and within the limitation of the studies included, preparation of a glide path using rotary sequences performs similarly (in most of the component studies) or significantly better than manual preparation when assessing apical transportation or canal centring. When compared to the absence of a glide path, canal shaping following glide path preparation was of similar, or significantly better quality, in regard to apical transportation or canal centring.

Influence of clinical use on physical-structural surface properties and electrochemical potential of NiTi endodontic instruments.

AIM: To investigate the surface morphology and electrochemical potential of superelastic (SE), M-Wire (MW) and shape memory technology (SMT) NiTi instruments before and after single clinical use in vivo. METHODOLOGY: A total of 60 ProTaper Universal F2 (PTU-SE), ProTaper Next X2 (PTN-MW), Typhoon (TYP), Hyflex (HF) and Vortex Blue (VB), the last three SMT, and size 25, .06 taper (n = 6 of each type) files were examined. Scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS) and electrochemical potential analysis were employed before and after clinical use. Statistical analysis was performed with one-way analysis of variance and Bonferroni's post hoc test. Significance was determined at the 95% confidence level for both tests. RESULTS: SEM observations of new instruments indicated the presence of marks left by the machining process during manufacturing and EDS revealed the existence of an oxide coating on shape memory instruments. After clinical use, the five types were associated with propagation of transverse cracks 3 mm from the tip. The surface oxide layer of TYP, HF and VB instruments had microcracks in multiple directions, whilst TYP and HF had fragmentation in chip form of the oxide layer. EDS analysis demonstrated a significant reduction of the oxide layer in shape memory instruments, except for VB. Electrochemical potentials were higher for shape memory instruments than for M-Wire and superelastic NiTi instruments, respectively (P < 0.05). CONCLUSIONS: It appears that shape memory technology NiTi instruments have a dysfunctional oxide layer after clinical use. Additionally, they featured higher electrochemical potential relative to NiTi instruments manufactured from M-Wire, and conventional superelastic NiTi alloy.

New curricular design in biostatistics to prepare residents for an evidence-based practice and lifelong learning education: a pilot approach.

AIM: To develop, implement and evaluate an innovative curriculum in biostatistics in response to the need to foster critical thinking in graduate healthcare education for evidence-based practice and lifelong learning education. METHODOLOGY: The curriculum was designed for first-year residents in a postgraduate endodontic programme using a six-step approach to curriculum development to provide sufficient understanding to critically evaluate biomedical publications, to design the best research strategy to address a specific problem and to analyse data by appropriate statistical test selection. Multiple learner-centred instructional methods and formative and summative assessments (written tasks, simulation exercises, portfolios and pre-post knowledge tests) were used to accomplish the learning outcomes. The analysis of the achievement of the group of students and a satisfaction survey for further feedback provided to the residents at the end of the curriculum were used for curriculum evaluation. RESULTS: All residents demonstrated competency at the end of the curriculum. The correct answer rate changed from 36.9% in the pre-test to 79.8% in the post-test. No common errors were detected in the rest of the assessment activities. All participants completed the questionnaire demonstrating high satisfaction for each independent category and with the overall educational programme, instruction and course in general. CONCLUSIONS: The curriculum was validated by the assessment of students' performance and a satisfaction survey, offering an example of a practical approach to the teaching of statistics to prepare students for a successful evidence-based endodontic practice and lifelong learning education as practicing clinicians.

Effects of two calcium silicate cements on cell viability, angiogenic growth factor release and related gene expression in stem cells from the apical papilla.

AIM: To evaluate the effects of two types of calcium silicate cements on viability, angiogenic growth factor release, and angiogenic and inflammation-related gene expression in human stem cells from the apical papilla (SCAP). METHODOLOGY: SCAPs were grown for 7 days with either ProRoot mineral trioxide aggregate (MTA) or Biodentine (BD). Cell viability and media concentrations of vascular endothelial growth factor (VEGF/VEGFA) and angiopoietin 1 (ANGPT1) were measured. The expression of genes related to angiogenic potential and inflammatory response was measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). One-way and two-way analyses of variance with multiple comparisons Tukey's test were performed (P < 0.05). RESULTS: Cells in contact with either cement were associated with increased cell viability compared with the no-treatment group at day 1 but there were no differences amongst groups at days 3 and 7. Exposure to either cement significantly increased VEGF concentrations at day 3; however, ANGPT-1 levels decreased significantly compared with the no-treatment group at day 3. Exposure to MTA and BD stimulated expression of VEGFA and FIGF/VEGFD. Furthermore, exposure to both cements significantly decreased the mRNA levels of ANGPT1 and FGF2 relative to the no-treatment group. CONCLUSIONS: Both MTA and BD stimulated the expression of angiogenic genes and release of VEGF, inducing similar expression patterns; however, they appeared to inhibit the expression of specific genes, including ANGPT1 and FGF2.

Evaluating gambles using dynamics.

Gambles are random variables that model possible changes in wealth. Classic decision theory transforms money into utility through a utility function and defines the value of a gamble as the expectation value of utility changes. Utility functions aim to capture individual psychological characteristics, but their generality limits predictive power. Expectation value maximizers are defined as rational in economics, but expectation values are only meaningful in the presence of ensembles or in systems with ergodic properties, whereas decision-makers have no access to ensembles, and the variables representing wealth in the usual growth models do not have the relevant ergodic properties. Simultaneously addressing the shortcomings of utility and those of expectations, we propose to evaluate gambles by averaging wealth growth over time. No utility function is needed, but a dynamic must be specified to compute time averages. Linear and logarithmic "utility functions" appear as transformations that generate ergodic observables for purely additive and purely multiplicative dynamics, respectively. We highlight inconsistencies throughout the development of decision theory, whose correction clarifies that our perspective is legitimate. These invalidate a commonly cited argument for bounded utility functions.

Validated finite element analyses of WaveOne Endodontic Instruments: a comparison between M-Wire and NiTi alloys.

AIM: To validate torsional analysis, based on finite elements, of WaveOne instruments against in vitro tests and to model the effects of different nickel-titanium (NiTi) materials. METHODOLOGY: WaveOne reciprocating instruments (Small, Primary and Large, n = 8 each, M-Wire) were tested under torsion according to standard ISO 3630-1. Torsional profiles including torque and angle at fracture were determined. Test conditions were reproduced through Finite Element Analysis (FEA) simulations based on micro-CT scans at 10-µm resolution; results were compared to experimental data using analysis of variance and two-sided one sample t-tests. The same simulation was performed on virtual instruments with identical geometry and load condition, based on M-Wire or conventional NiTi alloy. RESULTS: Torsional profiles from FEA simulations were in significant agreement with the in vitro results. Therefore, the models developed in this study were accurate and able to provide reliable simulation of the torsional performance. Stock NiTi files under torsional tests had up to 44.9%, 44.9% and 44.1% less flexibility than virtual M-Wire files at small deflections for Small, Primary and Large instruments, respectively. As deflection levels increased, the differences in flexibility between the two sets of simulated instruments decreased until fracture. Stock NiTi instruments had a torsional fracture resistance up to 10.3%, 8.0% and 7.4% lower than the M-Wire instruments, for the Small, Primary and Large file, respectively. CONCLUSION: M-Wire instruments benefitted primarily through higher material flexibility while still at low deflection levels, compared with conventional NiTi alloy. At fracture, the instruments did not take complete advantage of the enhanced fractural resistance of the M-Wire material, which determines only limited improvements of the torsional performance.

Determining cutting efficiency of nickel-titanium coronal flaring instruments used in lateral action.

AIM: To develop a method to evaluate the cutting behaviour of nickel-titanium (NiTi) coronal flaring instruments. METHODOLOGY: BioRaCe BR0 (BR), HyFlex CM 1 (HY), ProFile OS No. 2 (PF) and ProTaper Sx (PT) instruments were used in simulated coronal flaring using a lateral action against bovine dentine blocks, at 250 and 500 rpm. Cutting efficiency was assessed by three methods: first, areas of notches produced by instruments were directly measured under a stereomicroscope. Second, dentine specimens were then analysed by surface profilometry to determine the maximum cutting depth and finally by microcomputed tomography to assess the volume of removed dentine. Data were compared using parametric tests with the significance level set at 0.05. RESULTS: For all three methods, HY and PF were the most and the least cutting-efficient instruments, respectively (P < 0.05). Significant differences were detected between 250 and 500 rpm for HY and PT (area); for BR, HY and PT (depth); and for BR and HY (volume). There were strong positive correlations between the results obtained with those three different methods with r-values ranging from 0.81 to 0.92. CONCLUSION: Measuring the amount of material removed in a specific time under stereomicroscopy is a simple and rational way to assess the cutting behaviour of NiTi rotary instruments in lateral action. HyFlex, manufactured with thermomechanically treated NiTi wire, was the most efficient instrument, and increased rotational speed was associated with increased cutting efficiency.

The Therapeutic Use of Dental Mesenchymal Stem Cells in Human Clinical Trials.

Mesenchymal stem cells (MSCs), characterized by their undifferentiated and multipotent nature, can be derived from various sources, including bone marrow, adipose, and dental tissues. Among these, dental MSCs (DSCs) exhibit universal MSC characteristics and are attracting considerable attention for regenerating oral and craniofacial tissues. This review provides a contemporary overview of recently published clinical studies using DSCs for various orodental and maxillofacial regenerative applications, including bone, periodontal, and endodontic regeneration. It also explores the utilization of DSCs in treating systemic conditions, exemplified by their application in managing conditions such as COVID-19 and osteoarthritis. The available evidence underscores the potential of DSCs and their secretome as efficacious tools in regenerative medicine for both dental and nondental clinical applications, supporting the continued promise of stem cell-based therapies. It is nevertheless evident that there are a number of important challenges that restrict the widespread utilization of DSCs, namely, difficulty in standardizing autologous preparations, insufficient cell surface marker characterization, high production costs, and regulatory compliance requirements. Further, the unique requirements of dental applications, especially complex structures such as the periodontium, where temporospatial control over the healing process is required, necessitate the combination of stem cells with appropriate scaffolds according to the principles of tissue engineering. There is currently insufficient evidence to support the clinical translation of DSCs into clinical practice, and phase 3 clinical trials with standardized protocols for cell sourcing, propagation, dosing, and delivery are required to move the field forward. In summary, this review provides a contemporary overview of the evolving landscape of stem cell therapy, offering insights into the latest developments and trends as well as the challenges that need to be addressed for the widespread application of DSC-based cell therapies.