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.

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.

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.

Factors influencing treatment decisions in permanent mature teeth with irreversible pulpitis: a questionnaire-based study.

BACKGROUND: Decision-making in dentistry is a complex process, and this study evaluated factors that influence dentists' approaches in permanent mature teeth with irreversible pulpitis. METHODS: An online questionnaire was distributed to a group of dental practitioners. The questionnaire surveyed dentists' opinions about the management of vital permanent teeth with irreversible pulpitis including a case scenario. RESULTS: Data from 262 respondents were analysed. Barriers to perform vital pulp therapy (VPT) included presuming it an inappropriate long-term treatment (29.7%), lack of knowledge, insufficient access to materials, inadequate training and lack of confidence. Patient's preference (79.44%) and tooth restorability (91%) were the most frequently reported factors influencing treatment decisions. Dentists aged 25-35 years and who have 1-5 years of experience ranked extraction as a more successful treatment (P = 0.008; P = 0.003, respectively). Non-Australian graduates ranked pulpotomy to be a more successful procedure (P = 0.007), and public sector/hospital practitioners favoured extraction more than practitioners from other sectors (P = 0.003). Postgraduates/specialists preferred pulpotomy (P = 0.012) more than general dentists. Participants' clinical approaches for the management of symptomatic irreversible pulpitis: root canal treatment (45.0%), indirect pulp capping (22.9%), direct pulp capping (15.8%), pulpotomy (17.1%) and extraction (6.3%). CONCLUSIONS: Female, more experienced, overseas-educated dentists and endodontists preferred VPT for irreversible pulpitis in permanent mature teeth more than other participants. © 2024 Australian Dental Association.

Orifice barriers to prevent coronal microleakage after root canal treatment: systematic review and meta-analysis.

AIMS: This systematic review aimed to compare the efficiency of orifice barriers in preventing coronal microleakage in vitro. METHODS: Articles published in English, German and Chinese were searched for studies describing microleakage assays for the bacterial penetration of root canal-treated teeth in vitro. The final sample included 18 articles for review and meta-analysis. Risk ratios and confidence intervals were determined for dichotomous variables. Ten publications using bacterial leakage models contributed to the meta-analysis. RESULTS: The addition of orifice barriers to a root canal filling was overall effective, shown by risk ratios (RR) and 95% confidence intervals (CI) demonstrating reduced microleakage with glass ionomer cement (GIC) (RR 0.37, 95% CI 0.26-0.53, P < 0.001), resin-modified GIC (RR 0.32, 95% CI 0.15-0.67, P = 0.01), composite resin (RR 0.54, 95% CI 0.38-0.75, P < 0.001), mineral trioxide aggregate (MTA) (RR 0.25, 95% CI 0.12-0.52, P < 0.001) and Cavit (RR 0.23, 95% CI 0.14-0.39, P < 0.001). There were no significant differences between GIC, resin-modified GIC, composite resin and MTA orifice barriers. CONCLUSIONS: Placement of an orifice barrier over the root canal filling is effective in the prevention of coronal microleakage in vitro. Other parameters may also affect the effectiveness of orifice barriers, including thickness and duration of exposure to the oral environment. © 2023 Australian Dental Association.

Interactions between immune system and mesenchymal stem cells in dental pulp and periapical tissues.

The recent isolation and characterization of mesenchymal stem cells (MSCs) in dental tissues constitutes a major step forward in the development of new treatment strategies. MSCs are essential for dental pulp repair and the success of regenerative endodontic procedures. It is important to understand that immune cells and cytokines can affect stem cell function, which can impact their healing potential. On the other hand, stem cells are immunoprivileged and have the ability to modulate immune and inflammatory responses, which can be utilized to improve treatments outcome. This review addresses both aspects of this interaction and suggests that any change on both sides can tip the balance in favour of either persistence of inflammation or healing. Finally, the therapeutic relevance of the interaction between MSCs and immune system relative to current treatments is discussed, and future research and treatment perspectives are suggested.

An in vitro assessment of the physical properties of novel Hyflex nickel-titanium rotary instruments.

AIM: To determine several properties including torsional and fatigue limits, as well as torque during canal preparation, of Hyflex, a rotary instrument manufactured from so-called controlled memory nickel-titanium alloy. METHODOLOGY: The instruments were tested in vitro using a special torque bench that permits both stationary torque tests according to ISO3630-1 and fatigue limit determination, as well as measurement of torque (in Ncm) and apical force (in N) during canal preparation. Fatigue limit (in numbers of cycles to failure) was determined in a 90°, 5 mm radius block-and-rod assembly. Simulated canals in plastic blocks were prepared using both a manufacturer-recommended single-length technique as well as a generic crown-down approach. anova with Bonferroni post hoc procedures was used for statistical analysis. RESULTS: Torque at failure ranged from 0.47 to 1.38 Ncm, with significant differences between instrument sizes (P < 0.0001). Fatigue life ranged from 260 to 2565, with the shortest and longest lifespan for instruments size 20, .04 taper and size 25, .08 taper, respectively. Torque during canal preparation was significantly higher for small instruments used in the single-length technique but lower for the size 40, .04 taper, compared to a crown-down approach. No instrument fractured; 82% of the instruments used were plastically deformed; however, only 37% of these remained deformed after a sterilization cycle. CONCLUSIONS: Hyflex rotary instruments are bendable and flexible and have similar torsional resistance compared to instruments made of conventional NiTi. Fatigue resistance is much higher, and torque during preparation is less, compared to other rotary instruments tested previously under similar conditions.