Cyclic fatigue resistance, number of uses, and morphological/chemical analysis of RCS Rainbow Files, VDW Rotate and ProTaper Ultimate: in vitro study Tayná Lopes da Silva, Patrícia Carla Lopes, Mírian Galvão Bueno de Rezende, Amjad Abu Hasna BMC Oral Health, 2025 BACKGROUND: This in vitro study aimed to evaluate the cyclic fatigue resistance and number of uses post-sterilization of three rotary systems: ProTaper Ultimate, VDW Rotate, and RCS Rainbow Files. The study also sought to assess surface topography and chemical composition using scanning electron microscopy (SEM), and Energy-Dispersive Spectroscopy (EDS). METHODS: The cyclic fatigue resistance was evaluated using simulated artificial canal. The number of uses post-sterilization was evaluated using ninety extracted human upper and lower molars selected under strict inclusion criteria. Standardized root canal instrumentation was performed, followed by Scanning Electron Microscopy (SEM) at four moments including: unused instrument (baseline), after the 1st, 2nd and 3rd uses, and Energy-Dispersive Spectroscopy (EDS) analysis only for unused instruments. The data were subjected to a normality test, followed by one-way ANOVA and Tukey's post-hoc analysis, with a significance level set at α ≤ 0.05. RESULTS: It was found that RCS Rainbow One Files and VDW Rotate exhibited significantly greater cyclic fatigue resistance compared to ProTaper Ultimate (P = 0.0006). Despite this, all systems exhibited increased surface deterioration and susceptibility to fracture after repeated uses and autoclave sterilization, without significant difference in total fractures number among the groups; SEM analysis revealed progressive surface deterioration, microcrack formation, and deformation after each use, particularly after the second and third uses; and EDS analysis indicated the presence of residual elements such as carbon, aluminum, and oxygen, suggesting contamination and potential material instability. CONCLUSION: RCS Rainbow One Files and VDW Rotate demonstrated superior cyclic fatigue resistance compared to ProTaper Ultimate; however, all systems became increasingly prone to fracture following repeated clinical use and autoclave sterilization, without significant differences in total fractures. These findings reinforce the need for cautious reuse of NiTi rotary instruments, as repeated use may compromise safety and treatment outcomes.
Treatment outcomes of pulpotomy in primary molars utilizing 2.25% sodium hypochlorite gel: a randomized controlled trial Mawia Karkoutly, Amirah Alnour, Amjad Abu Hasna, Ok Hyung Nam, Saleh Al Kurdi, Nada Bshara BMC Oral Health, 2025 BACKGROUND: Sodium hypochlorite (NaOCl) gel can be a potential substitute in daily pediatric dentistry practice. Given its high antimicrobial efficacy, NaOCl gel is expected to induce healing and improve pulpotomy treatment outcomes. This study aimed to perform a histological, clinical, and radiographical evaluation of pulpotomy in human primary molars utilizing 2.25% (NaOCl) gel as a medicament, followed by white mineral trioxide aggregate (WMTA) as a base material. MATERIALS AND METHODS: A randomized, second-blinded, split-mouth clinical trial was conducted in cooperative patients aged 8-10 years with 48 carious first primary molars, which were treated by: (I) NaOCl gel group: following hemostasis, teeth were pulpotomized utilizing 2.25% NaOCl gel, and then WMTA paste was applied as a dressing material, and (II) control group: following hemostasis, WMTA paste was applied as a dressing material. Later, each group was sub-divided into three sub-groups (n = 8) according to the time planned for serial extraction: (I) 7 days, (II) 30 days, and (III) 90 days for histological evaluation. In addition, 40 s primary molars in cooperative patients aged 5-10 years indicated for pulpotomy were randomly allocated into two groups for clinical and radiographical evaluation at 3, 6, and 12 months follow-up. Data were analyzed by applying the chi-square test (p < 0.05). RESULTS: NaOCl gel improved odontoblastic integrity and dentin bridge formation (p < 0.001) without increasing pulp necrosis or calcifications. The NaOCl gel group showed a 90% clinical and radiographical success rate at 3, 6, and 12 months of follow-up. In the control group, the clinical success rate was 85% after 3, 6, and 12 months, whereas the radiographical success rate was 100% at 3 months and decreased to 85% after 6 and 12 months. CONCLUSIONS: Utilizing 2.25% NaOCl gel as a medicament in human primary molars pulpotomy improved the treatment outcomes of the WMTA. TRIAL REGISTRATION: ISRCTN registry, ISRCTN15908457, registered 22 July 2024.
Clinical and radiographic outcomes after pulpotomies using mineral trioxide aggregate mixed with distilled water or 2.25% sodium hypochlorite gel: a randomized controlled clinical trial Mawia Karkoutly, Amjad Abu Hasna, Ok Hyung Nam, Ricardo Machado, Saleh Al Kurdi, Nada Bshara Bdj Open, 2025 Objectives Sodium hypochlorite (NaOCl) gel is an effective additive for white mineral trioxide aggregate (WMTA) that enhances its chemical and physical characteristics and significantly reduces setting time while maintaining biocompatibility. The study sought to compare the outcomes of pulpotomies performed in primary teeth using WMTA mixed with 2.25% NaOCl gel or WMTA mixed with distilled water (DW). Materials and methods It was a randomized, triple-blinded, split-mouth, controlled clinical trial. Forty primary second molars from cooperative children aged 5–10 who required pulpotomy were randomly assigned to the control group—WMTA + DW or experimental group—WMTA + NaOCl gel for clinical and radiographic assessments at 3, 6, and 12 months of follow-up. The clinical evaluation involved checking for spontaneous pain, pain on percussion, tooth mobility, abscesses, sinus tracts, and the exfoliation of the treated tooth. The periapical radiographic evaluation identified whether there was furcal radiolucency, internal or external root resorption, and widening of the periodontal ligament. Canal obliteration was not considered a failure. Results The WMTA + NaOCl gel group showed a 90% and 95% clinical and radiographical success rate, respectively, at 3, 6, and 12 months of follow-up. In the control group, the clinical success rate was 90% after 3, 6, and 12 months, whereas the radiographical success rate was 100% at 3 months and decreased to 95% after 6 and to 85% after 12 months. No statistically significant difference was detected between the two groups (p > 0.05). Conclusions The present research validated WMTA + NaOCl gel as a potentially effective material for pulpotomy in primary molars.
Physicochemical evaluation of mineral trioxide aggregate and five mineral oxides calcium silicate-based cements Larissa Carvalho Novaes Batista, Jaqueline Martins Crivelari, João Vitor da Cruz Pegoraro, Ana Cristina Padilha Janini, Marina Angélica Marciano, Camila Soares Lopes, Maisour Ala Rachi, Amjad Abu Hasna, Bruno Martini Guimarães BMC Oral Health, 2025 BACKGROUND: Five mineral oxides (5MO, Golden Yatti LLC) is an endodontic calcium-silicate based repair cement. This study aimed to evaluate physicochemical properties, chemical composition and surface characterization of the 5MO material in comparison to White MTA (Angelus). METHODS: The setting time was evaluated using the Gillmore needle. The pH was measured with a pH-meter after 3, 12, 24 h, 3, 7, 14 and 21 days. Solubility was determined after immersion in phosphate-buffered saline (PBS) for 7 days. Surface analysis of the cements was conducted using scanning electron microscopy (SEM) and a coupled energy-dispersive spectroscopy (EDS), and other chemical analysis was performed through Fourier transform infrared spectroscopy (FTIR). Data were analyzed using Student's t test (p ≤ 0.05). RESULTS: Both materials had an alkaline pH in all periods analyzed; however, after 21 days, White MTA presented a higher pH (p ≤ 0.05). The 5MO material took longer to set and had greater solubility (p ≤ 0.05). Surface characterization using SEM/EDS highlighted distinct particle morphologies and elements, like carbon, oxygen, calcium, silicon, and other trace elements in 5MO and White MTA. FTIR analysis revealed an absorption band at 1400 cm⁻¹ associated with the C-O stretching of carbonate groups. The band at 3200 cm⁻¹ corresponds to the C-H vibrations, which is characteristic of hydrated ceramics. CONCLUSION: While the 5MO material exhibits promising alkalinity and elemental composition favorable for tissue regeneration, its longer setting time and greater solubility in comparison to White MTA may compromise the integrity of the seal, promoting bacterial recontamination.
Active Learning in Remote Teaching from the Perspective of Brazilian Dentistry Students: an observational cross-sectional study Ellen Eduarda FERNANDES, Anderson de Oliveira NASCIMENTO, Jacqueline Maria FERREIRA, Amjad ABU HASNA, Miguel Angel Castillo SALGADO, Luana Marotta Reis de VASCONCELLOS, Marianne SPALDING Brazilian Dental Science, 2025 Objective: This study aimed to analyze the perceptions of first-year Dentistry students at a Brazilian public university, emphasizing the implementation of active methodologies during the remote teaching period. Material and Methods: Using a flipped classroom model combined with active methodologies and digital tools, the Histology and Embryology course integrated asynchronous video lectures, synchronous discussions, virtual microscopy, and diverse activities such as case studies and schematic drawings. Assessments included diagnostic tools and formative assessments, with individualized feedback and supplemental assignments for students who needed additional support. This cross-sectional study was conducted to assess student perceptions of these methodologies and their potential for future application. Results: Regarding the overall dynamic of the course, 63.5% of the students rated it as “excellent.” As for the tools employed, the positive percentage ranged from 87.55% to 94.4%. When asked about the challenges faced, issues related to internet connectivity and motivation were highlighted. Conclusion: This study concludes that the flipped classroom approach, combined with other active methodologies, provided a beneficial environment for the development of the course in the online format. This study’s limitations include the absence of a direct comparison between traditional teaching, flipped classroom methodologies, and hybrid approaches, highlighting the need for future research to evaluate their effectiveness comparatively. KEYWORDS Active learning; Education; eLearning; Histology; Perception.
Antibacterial and Antibiofilm Effect of Lavandula dentata L. Essential Oil as Endodontic Irrigant Against Standard and Clinical Strains of Enterococcus spp. Caroline Trefiglio Rocha, Patrícia Michelle Nagai de Lima, Thaís Cristine Pereira, Lara Steffany de Carvalho, Mariana Gadelho Gimenez Diamantino, Amjad Abu Hasna, João Carlos da Rocha, Luciane Dias de Oliveira, Cláudio Antonio Talge Carvalho Applied Sciences Switzerland, 2025 Enterococcus faecalis and Enterococcus faecium are frequently associated with persistent endodontic infections due to their ability to form biofilms and resist conventional treatments. The aim of this study was to evaluate the antibacterial and antibiofilm effects of Lavandula dentata L. essential oil at 100% against the standard and clinical strains of Enterococcus spp. The minimum bactericidal concentration (MBC) of L. dentata essential oil for each bacterial strain was determined. The antibiofilm effect was evaluated by an MTT assay. Data were statistically analyzed by the ANOVA and Tukey test, with a significance level of 5%. The MBC value was 32% (292.8 mg/mL) against all the tested strains. L. dentata significantly reduced E. faecalis and E. faecium biofilms at 16–64% (146.4–585.6 mg/mL) concentrations, with effects comparable to 2% chlorhexidine (CHX) (p ≥ 0.05). Biofilm reduction was strain-dependent at 30 min but showed broader efficacy after 24 h, particularly against E. faecium clinical strains (p ≤ 0.001). L. dentata demonstrated effective antimicrobial activity against planktonic and biofilm forms of E. faecalis and E. faecium as it reduced biofilm formation at a concentration of 16% and 64% (146.4 and 585.6 mg/mL), with results comparable to 2% CHX after 30 min and 24 h. L. dentata EO may serve as a potential alternative or adjunctive antimicrobial agent in endodontic treatment. However, the study’s limitations included the in vitro design and lack of cytotoxicity assessment.
Anti-Planktonic, Antibiofilm, and Synergistic Effects of Nasturtium officinale and Psidium guajava Hydroethanolic Extracts Against Standard and Clinical Strains of Enterococcus faecalis Lara Steffany de Carvalho, Livia Ramos Dorta da Silva, Cláudio Antonio Talge Carvalho, Maria Cristina Marcucci, Luciane Dias de Oliveira, Amjad Abu Hasna Applied Sciences Switzerland, 2025 Enterococcus faecalis is strongly associated with secondary/persistent root canal infections, being the most prevalent bacterium in cases of apical periodontitis in previously treated teeth. This study was elaborated to evaluate the anti-planktonic, antibiofilm, and synergistic effects of Nasturtium officinale and Psidium guajava hydroethanolic extracts against standard and clinical strains of E. faecalis. Firstly, the N. officinale extract was prepared from watercress leaves, and P. guajava extract was prepared from guava tree leaf shoots. Then, the content of soluble solids was quantified in both. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of the isolated N. officinale and P. guajava extracts for each bacterial strain were determined using the broth microdilution method, following the Clinical and Laboratory Standards Institute (CLSI) guideline M7-A9. The MTT assay was used to evaluate the antibiofilm activity, and the fractional bactericidal concentration index (FBCI) was utilized to evaluate the synergistic effect of the N. officinale and P. guajava extracts using the checkerboard technique. Again, the MTT assay was used to evaluate the antibiofilm activity of the combined extracts this time. The data were subjected to statistical analysis using ANOVA and Tukey’s test, with a significance level of p ≤ 0.05. It was found that the soluble solid content of N. officinale was 50 mg/mL, and of P. guajava was 33.5 mg/mL. The MBC value of N. officinale was 12.5 mg/mL, and of P. guajava was 0.52 mg/mL against all the tested strains of E. faecalis. The combined 0.1 mg/mL N. officinale + 0.1 mg/mL P. guajava, and 0.1 mg/mL N. officinale + 0.5 mg/mL P. guajava hydroethanolic extracts effectively reduced the biofilm formation of the standard and clinical strain 4 of E. faecalis. Therefore, these combined extracts may be considered as endodontic irrigants in future studies.
Psidium guajava L. hydroethanolic extract as endodontic irrigant: phytochemical analysis, antioxidant activity, antimicrobial action and biocompatibility Lara Steffany de Carvalho, Vanessa Marques Meccatti-Domiciano, Livia Ramos Dorta da Silva, Maria Cristina Marcucci, Cláudio Antonio Talge Carvalho, Amjad Abu Hasna, Luciane Dias de Oliveira Peerj, 2025 Background The search for novel antimicrobial agents in Endodontics is constant to overcoming persistent infections. Psidium guajava L. is a medicinal plant little explored in Endodontics. The aim of this study was to produce hydroethanolic extract of P. guajava L. and to evaluate its phytochemical composition, antimicrobial and antibiofilm action against standard and clinical strains of Enterococcus faecalis and Candida albicans, and cytotoxicity and genotoxicity on human keratinocyte cultures (HaCaT cells). The findings provide new insights into the potential of P. guajava as an alternative endodontic antimicrobial agent, contributing to the development of more effective and biocompatible therapeutic strategies. Methods P. guajava hydroethanolic extract was produced using young leaves of guajava and extracted using absolute ethanol and ultrapure water in a ratio (30 g:100 mL). The solid soluble, total flavonoid and total phenols content were determined. The chemical composition was determined via high-performance liquid chromatography (HPLC) analysis, then the free radical suppressive activity was assessed by determining the IC50 value, indicating the concentration required to eliminate 50% of free radicals. Later, the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) of the extract was evaluated against the strains using clinical and laboratory standards institute (CLSI) guidelines (M27-S4 and M7-A9). Then, the antibiofilm activity was evaluated via MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. Finally, the cytotoxicity of the extract was evaluated via Alamar Blue assay, and the genotoxicity via micronucleus assay on human keratinocyte cultures (HaCaT cells). Data were analyzed using ANOVA and Tukey’s test or Kruskal-Wallis and Dunn’s test. Results The soluble solids content in the extract was 3.35%. Using the quercetin standard curve, the total flavonoid concentration was 0.130 ± 0.110 mg/mL. In addition, using standard curve for phenolic acids, the total phenolic concentration was 1.770 ± 1.540 mg/mL. HPLC analysis revealed peaks of rutin, quercetin and kaempferol as major flavonoids in the P. guajava L. extract. The extract demonstrated notable antioxidant activity, with an IC50 value of 10.39 µg/mL. The MMC values ranged 1.04–8.37 mg/mL. The extract at 8.37 mg/mL was effective in reducing the biofilms of standard and clinical strains of E. faecalis and C. albicans after 10 min. Cytotoxicity analysis revealed that all tested concentrations exhibited relatively low toxicity toward HaCaT cells. Genotoxicity assessment via the micronucleus assay indicated minimal DNA damage at all tested concentrations. Overall, P. guajava L. hydroethanolic extract at 8.37 mg/mL is the most effective concentration in reducing the biofilm of the standard and clinical strains of E. faecalis and C. albicans, while maintaining biocompatibility with HaCaT cultures.
Analysis of pulp histological response to pulpotomy performed with white mineral trioxide aggregate mixed with 2.25% sodium hypochlorite gel in humans: a randomized controlled clinical trial Mawia Karkoutly, Amirah Alnour, Jamal Alabdullah, Amjad Abu Hasna, Ok Hyung Nam, Darin Jalloul, Saleh Al Kurdi, Nada Bshara Scientific Reports, 2024 This study aimed to evaluate the histological success of pulpotomy in primary molars using white mineral trioxide aggregate (WMTA) mixed with 2.25% sodium hypochlorite (NaOCl) gel and to evaluate in vitro its physical and chemical properties. The study had a clinical stage and an in-vitro stage. The clinical study was conducted with 24 patients aged 8-10 years. It was a randomized controlled trial to perform a histologic evaluation of pulp response following pulpotomy. Primary first molars were randomly assigned in split mouth model to control group-WMTA + distilled water (DW) or experimental group - WMTA + NaOCl gel. Teeth were extracted after 7, 30 or 90 days and submitted to histological analysis. The second stage was an in-vitro study to evaluate the physical and chemical properties of the two materials tested. SEM and EDX analyses and pH level evaluations were performed after 24 h and 28 days. The histological findings revealed that while WMTA + NaOCl gel group showed better odontoblastic integrity (P < 0.05), WMTA + DW group had more favorable outcomes in dentin bridge formation and pulp calcification (P < 0.05). Pulp tissue hemorrhage and pulp fibrosis were similar between them (P > 0.05). Regarding materials' in vitro evaluation, the pH level indicated a higher initial pH for the WMTA + NaOCl gel group, which equalized after 28 days. SEM analysis initially showed a less homogeneous surface for WMTA + NaOCl gel, but it became similar after 28 days. EDX analysis indicated higher calcium and silicon percentages in the WMTA + NaOCl gel group initially, which increased in both groups after 28 days. Adding 2.25% NaOCl gel to WMTA enhanced odontoblastic integrity in both the short and medium term. In addition, it had a similar chemical composition, surface morphology, and alkalinity when compared to WMTA + DW mixture.
