Mohannad Nassar

Aim: The use of antibiotics in clinical practice is shaped by the adequate knowledge acquired during professional education. The survey aimed to evaluate the knowledge of final‐year undergraduate and postgraduate endodontic students regarding the use of antibiotics in endodontic management. Methodology: The survey was distributed to final year undergraduates and postgraduate endodontic students across 10 dental schools in different countries. The questionnaire included demographic data and assessed the respondents' knowledge of current guidelines and antibiotic use in endodontic scenarios. The survey instrument was validated and piloted prior to distribution. Responses were summarised using frequencies and percentages. Undergraduate and postgraduate students were compared using Pearson's chi‐squared or Fisher's exact tests. An institution‐equalised sensitivity analysis assessed the influence of institutional participation, and a multivariable logistic generalised estimating equation (GEE) model evaluated factors associated with guideline‐concordant responses across clinical scenarios. Results: The overall response rate for undergraduate students was 37.3%, and for postgraduate students was 87.9%. Most respondents recognised that systemic antibiotics were generally not indicated for localised endodontic infections without systemic involvement but were indicated for acute apical abscess with systemic involvement and after replantation of an avulsed permanent tooth. Awareness of the European Society of Endodontology ( ESE ) guidelines was 49.1% among undergraduate and 82.6% among postgraduate respondents, whereas awareness of the American Association of Endodontists ( AAE ) guidelines was 70.4% and 91.7%, respectively ( p < 0.001 for both comparisons). Awareness of ESE guidelines was independently associated with greater odds of a guideline‐concordant response (adjusted OR = 1.39, 95% CI 1.03–1.88; p = 0.029), whereas postgraduate status was not (adjusted OR = 1.36, 95% CI 0.97–1.91; p = 0.070). Institution‐equalised estimates supported the qualitative interpretation of most outcomes, although the undergraduate estimate recommending prophylaxis before non‐surgical root canal treatment in patients with prosthetic joint replacement within the previous 3 months decreased from 52.5% to 37.2%. Conclusions: Among respondents from the participating dental schools, knowledge of appropriate antibiotic use was identified across clinical scenarios, with variability particularly in antibiotic selection for patients with true penicillin allergy, use of loading doses and prophylactic antibiotic recommendations. Continued integration of antimicrobial stewardship principles into dental education curricula is warranted.

This study evaluated the effects of chelating agents on the shear bond strength (SBS) of resin‐modified calcium‐silicate (RMCS) to dentine, as well as their impact on smear layer removal. Flat dentine surfaces from human molars were conditioned using 1% chitosan nanoparticles (CNP), 6% CNP, 9% etidronic acid (EA), 2.5% phytic acid (IP6), 7% malic acid (MA), 7% maleic acid (MeA), 10% citric acid (CA), 17% EDTA, 5.25% sodium hypochlorite (NaOCl), or distilled water (control). RMCS were applied and tested for SBS. Smear layer removal was examined using SEM, and tubule patency was digitally analysed. EDTA and IP6 showed the highest SBS, while NaOCl and EA were lowest without statistical significance. MeA, CA, IP6, and MA removed more smear layer; MA and IP6 resulted in higher dentinal tubules patency than the control group. Bond strength partly depends on the conditioning agent, and complete smear layer removal did not ensure the highest values.

Aim: To investigate the current status of education in vital pulp treatment (VPT) for the management of permanent teeth in relation to undergraduate/pre‐doctoral students at a range of dental schools worldwide. Methodology: The web‐based survey consisted of 28 questions that had been validated and piloted by a range of experienced endodontists. Faculty members who taught endodontics at one dental school in each selected country participated in the survey, which was completed in March 2025. Simple descriptive statistics were used to present the data. Results: Forty faculty members from various countries completed the survey; the majority of which (82.5%) worked at public universities. All participating dental schools included VPT teaching in their undergraduate/predoctoral curricula. The primary method of teaching VPT in the majority of dental schools was didactic lectures. VPT preclinical exercises were included in only 32.5% of the schools. The vast majority of dental schools did not require students to pass a preclinical or clinical competency examination in relation to VPT prior to graduation. Hydraulic calcium silicate materials were the most commonly used for exposed pulps but not for pulps that were not exposed. Conclusions: VPT has been integrated into the undergraduate/pre‐doctoral curriculum of all dental schools that participated in this survey. However, the majority of dental schools that were surveyed lacked preclinical teaching and competency assessments for VPT in both preclinical and clinical scenarios.

Aim: The microbiota of endodontic infections in patients from the Arabian Gulf region (AGR) is largely unexplored. While research in different global regions has investigated the microbial composition of such infections, studies using shotgun metagenomic sequencing (SMS) alongside culture‐dependent techniques (CDT) are limited. There are also few in vitro biofilm models that reflect the microbial profiles of endodontic infections. Therefore, by employing SMS and CDT, this research aimed to explore compositional and functional microbial profiles of endodontic infections from the AGR. The research also sought to develop ex vivo biofilms directly from endodontic infection samples. Methodology: SMS and CDT were used to analyze 32 root canal samples from necrotic pulp. Patients' samples were categorized into two cohorts: symptomatic ( n = 19) and asymptomatic ( n = 13). Samples underwent sequencing followed by bioinformatic analysis to investigate microbial composition, resistome, virulome, and functional differences. Two representative samples (8R, 15R) were selected to develop ex vivo biofilms on hydroxyapatite coupons. Similarity between inoculum and developed biofilms was assessed using SMS and CDT. The reproducibility of developed biofilms was assessed based on microbial composition and relative abundance at the species level using correlation coefficient analysis. Results: Endodontic samples had high bacterial diversity, with a total of 366 bacterial species detected across the two cohorts. Several antibiotic resistance ( n = 59) and virulence ( n = 82) genes were identified, with no significant differences between the cohorts. CDT identified 28 bacterial species, with 71.4% of the isolated bacteria having phenotypic resistance to clinically relevant antibiotics. SMS showed that the ex vivo biofilms were polymicrobial. Biofilm derived from sample 15R had 9 species and was dominated by Enterococcus faecalis , while sample 8R had 12 species and was dominated by Streptococcus mutans . Pearson correlation analysis demonstrated a significant positive correlation between biological biofilm replicates, confirming the reproducibility of biofilm formation. Conclusions: There was high bacterial diversity in root canal samples from necrotic pulp. Samples were shown to contain antibiotic resistance and virulence genes, with no differences evident between symptomatic and asymptomatic infections. A high number of isolated bacteria were resistant to clinically used antibiotics. Ex vivo biofilm models from clinical samples were successfully developed and reproducibly reflected a polymicrobial composition.

Aim: To evaluate the current status of endodontic education and assessment at an undergraduate/predoctoral level in dental schools worldwide. Methodology: The current survey comprised a 50‐item online questionnaire related to undergraduate endodontic education. The project leaders emailed the survey's details to faculty members responsible for endodontic teaching at one dental school in every country to seek their willingness to participate in the survey. After the faculty members accepted, the survey details were sent to participants along with the survey link. Simple descriptive statistics were used to represent the data. Results: Amongst the 44 faculty members from different countries who agreed to participate, 36 completed the survey. Endodontic training starts in 50% of dental schools from the third year of the curriculum. Each dental school employs a diverse range of educational methods. During pre‐clinical training, 19.4% of the participating dental schools used only natural teeth. Stainless‐steel hand instruments, syringe irrigation with a needle, resin‐based sealer and the cold lateral compaction technique are the most frequently used in pre‐clinical and clinical training. A significant percentage of dental institutions necessitate that students treat a predetermined quantity of canals or teeth throughout their pre‐clinical and clinical education. Dental institutions conduct formative, summative or a combination of the formative and summative throughout the clinical and pre‐clinical phases of endodontic training. Conclusions: According to the data collected from this survey, there are considerable variations in the curriculum for undergraduate/predoctoral endodontic programmes amongst the surveyed dental schools. Pre‐clinical and clinical education should integrate a larger array of modern tools and procedures.

This study investigated phytic acid (IP6) effect on chemical, structural, and mechanical characteristics of nickel–titanium (NiTi) files. The tested files were equally divided into groups according to the immersion protocol: sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), IP6, EDTA followed by NaOCl, and IP6 followed by NaOCl. These groups were then compared in terms of Ni, Ti, and chromium (Cr) ions release from the files. Microstructural changes using field emission scanning electron microscope (Fe-SEM) and energy dispersive X-ray spectroscopy (EDX) and surface roughness were analyzed. The mechanical characterization was conducted using cyclic fatigue resistance test. Fractured segments were scanned under SEM. Statistical analysis was performed using one-way ANOVA, Tukey test, Kruskal–Wallis test and Mann–Whitney U test. Results showed that NaOCl caused significant release of Cr, followed by IP6 and EDTA (P < 0.05). When files were pre-immersed in EDTA, NaOCl tended to induce less release of Ti and Cr. EDX evaluation revealed that the main surface elements were Ni, Ti, carbon, and oxygen. EDTA group contained the highest amount of carbon, while the control group showed the lowest. Surface roughness evaluation revealed no significant differences between groups despite the minor increases after immersion in certain groups. Black areas were observed in the NaOCl group which indicated corrosion. However, the cyclic fatigue test showed no significant differences between the groups.

We assessed the effect of non-protein thiols (NPSH), reduced glutathione (GSH) and n-acetylcysteine (NAC), on resin shear bond strength (SBS) to hydrogen peroxide (H₂O₂)-treated dentin, and their effects on the characteristics of dentin in comparison to ascorbic acid (AA) and sodium thiosulfate (STS). H₂O₂-treated dentin was conditioned with 5% AA, GSH, NAC, or STS applied for 1 or 5 min. The positive control group received H₂O₂ without antioxidant application, and the first negative control group received distilled water (DW). The specimens received resin bonding immediately after treatment except for the second negative control group (delayed bonding). Microhardness, roughness, and topography were studied. The SBS values of all antioxidants were statistically greater than the positive control group (p < 0.05); however, NAC and AA applied for 1 min demonstrated the highest values, which were comparable to delayed bonding. All treatments removed the smear layer except DW, H₂O₂, and STS. The negative effect of H₂O₂ on resin–dentin bonding was mitigated by the application of the antioxidants; however, their efficiencies were dependent on the antioxidant type and time of application. NAC was more effective in optimizing resin bonding to bleached dentin compared to GSH at 1 min application and STS at both application times but was comparable to AA. Negligible negative effects on the substrate’s roughness and microhardness were detected. The antioxidant properties of the agent and its capacity to remove the smear layer are the processes underpinning the ability of a certain antioxidant to reverse the effect of H₂O₂ on bonding.