Conventional root canal therapy relies on mechanical instrumentation and chemical irrigation; however, the complex anatomy of the root canal system often compromises complete disinfection, particularly of anaerobic bacterial biofilms, resulting in persistent or recurrent infections. Laser-assisted endodontic therapy has emerged as an effective adjunct, enhancing antimicrobial efficacy through photothermal effects, photodynamic action, and cavitation, thereby improving disinfection in anatomically inaccessible regions. In addition, laser therapy has been shown to stimulate stem cell proliferation, modulate inflammatory responses, reduce postoperative pain, and promote apical tissue regeneratiojn. Currently, Er:YAG, diode, Nd:YAG, and CO2 lasers are widely used for refractory infection control, smear layer removal, and dentin hypersensitivity reduction. Moreover, laser-nanoparticle interactions further enhance antibacterial efficacy. This narrative review summarizes the applications of laser technology in root canal disinfection, pulp regeneration, and pain management, providing a scientific and clinical basis for the treatment of persistent fistulas and refractory root canal infections.

The maxillary second premolar, while frequently single rooted, exhibits a high degree of morphological diversity in its internal canal system. This unpredictability can lead to clinical oversights if a simple anatomy is assumed. The aim of this study was to review current knowledge regarding the number of roots and root canal configurations in permanent maxillary second premolars across different populations. A comprehensive literature search was conducted using the PubMed database for studies published between 2015 and December 2025, with the keyword "maxillary second premolar anatomy." Out of 358 identified articles, 27 studies met the inclusion criteria and were analyzed. Only human-based studies on maxillary second premolars that used CBCT imaging and were written in English were included. The reviewed studies revealed that single-rooted maxillary second premolars are the most prevalent morphology, occurring in over 70% of cases, although significant variations exist among different ethnic groups. The presence of two roots was the second most common configuration, while three-rooted teeth were rare (<2%). Gender-related differences were also observed, with a higher prevalence of two-rooted teeth in males. Analysis of root canal configurations based on Vertucci's classification demonstrated that all eight types can occur, with Type I being the most frequent in most populations with a result of more than 50% of all teeth. However, substantial variability was noted, with certain studies reporting a higher prevalence of more complex configurations such as Types IV and V. The findings emphasize the importance of thorough knowledge of root canal anatomy and its variations to ensure successful endodontic outcomes. Advanced imaging techniques, particularly cone beam computed tomography (CBCT), play a crucial role in improving diagnostic accuracy and proper endodontic treatment. Further research is needed to better understand anatomical differences across populations and enhance clinical decision-making in endodontics.

The understanding of morphological variations in the canal along with the ability to detect and manage the root canal system are essential for achieving a satisfactory endodontic treatment outcome. This case report presents the endodontic management of a C‐shaped maxillary second molar with five canals. Cone‐beam computerised tomography coupled with a dental operating microscope exhibited remarkable efficacy in the diagnosis, detection and treatment of this irregular morphological root canal system. Clinicians should be alert to anatomic variations in C‐shaped maxillary molars during endodontic treatment, even though these variations rarely occur.

Potential of Trichloroacetic Acid in Smear Layer and Calcium Hydroxide Removal in Root Canals\u2013Exploratory Pilot Studies In Vitro

AIM. To conduct a clinical assessment of the capabilities and manipulation characteristics of a modified tungsten alloy endodontic finishing file. MATERIALS AND METHODS. The study design involved the participation of 7 dentists with at least 10 years of experience performing endodontic treatment at 7 different medical clinics. Each of the specialists performed endodontic treatment of 15 teeth, both primary and repeated, in accordance with established diagnoses for diseases of the pulp and periodontium with optic magnification. The irrigation stage of the root canal system was complemented by the use of a finishing file made by twisting wire from a modified tungsten alloy with a bundle of microbristles on the end part. The study used 105 instruments in 105 clinical cases. To standardize the assessment of capabilities and manipulation characteristics, a specially designed questionnaire was used to comprehensively evaluate the work with the instrument. Clinical photo documentation of the work stages, data collection and archiving, statistical processing and subsequent analysis were carried out. The consistency of expert opinions was studied by calculating the Kendall concordance coefficient (W). RESULTS. The clinical capabilities and manipulative characteristics of a finishing endodontic file made of a modified tungsten alloy based on a standardized profile questionnaire have been determined. The moderate consistency of expert opinions ( W = 0.54) is statistically significant at a very high level ( p &lt; 0.001), which allows us to consider the expert assessments to be objective. The advantages and limitations of using these files are outlined. Clinical recommendations for the use of this instrument have been formulated. CONCLUSIONS. The use of a twisted-type endodontic finishing file made of a modified tungsten alloy in the root canal irrigation algorithm forms a new approach in endodontics aimed at improving root canal treatment and increasing the success of treatment in clinical dentistry. The results obtained will form the basis for the development of methodological approaches to conducting both laboratory and clinical research in this area.

To outline the biological and electrochemical principles supporting impedance-guided localisation of pulp chambers and canal orifices in calcified root canal systems, and to present an accessory concept relating to impedance patterns at the coronal dentine-gutta-percha interface, potentially serving as a surrogate marker of fluid leakage associated with deficient non-conductive root fillings. Calcific metamorphosis produces structural alterations that complicate localisation of pulp chambers and canal orifices. Adjunctive modalities such as CBCT, guided endodontics, microscopic magnification and ultrasonic troughing provide geometric information but lack real-time biological feedback. Electrical impedance behaviour differs significantly between sclerotic dentine and residual conductive pathways and offers a biological cue during access. The impedance-guided localisation concept applies these principles through a structured, conservative workflow. In addition, impedance patterns observed at coronal dentine-gutta-percha interfaces will, in theory, reflect electrochemical variations associated with potential fluid leakage and the reduced effectiveness of existing non-conductive root fillings to provide a fluid-tight seal. Impedance-guided localisation may provide a biologically grounded adjunct to visual and geometric strategies for locating pulp chambers and canal orifices when managing calcified root canal systems during root canal treatment. The interface-related impedance concept serves as an optional scientific extension, derived from established electrochemical principles, that may offer insight into potential fluid leakage or reduced sealing effectiveness associated with non-conductive root canal fillings. Impedance-guided pulp chamber and canal orifice localisation provides real-time biological feedback that reduces the risk of iatrogenic perforations and enhances conservative dentine management, particularly for inexperienced clinicians with potential relevance for preclinical training and early clinical education. The accessory interface-related impedance concept may offer surrogate insight into potential leakage or reduced sealing effectiveness of root fillings.

Evaluation of Organic Debris Removal by 2 Irrigant Activation Systems using a Novel Chairside Quantitative Assay.

Assessment of water quality in the main canal systems in Ho Chi Minh City, Vietnam

Multi-objective two-stage optimization of canal system scheduling in irrigation districts incorporating groundwater dynamic variations

Post-treatment Apical Periodontitis: Histobacteriologic and Histopathologic Findings.

BackgroundProper biomechanical preparation of the root canal system is fundamental to the success of endodontic therapy. Curved root canals represent a major clinical challenge, increasing the risk of procedural errors such as canal transportation, ledge formation, and instrument separation. This study aimed to evaluate the stress distribution in two single-file rotary systems subjected to different canal curvatures using three-dimensional finite element analysis (FEA).MethodsThree-dimensional CAD models of root canals with curvatures of 2°, 30°, and 45° were created, along with models of WaveOne Gold and One Curve rotary files. Finite element simulations were performed to replicate clinical instrumentation conditions, and the generated stresses were evaluated using the von Mises stress criterion.ResultsWaveOne Gold demonstrated maximum von Mises stress values of 375.42 MPa at 2°, 435.13 MPa at 30°, and 515.36 MPa at 45° curvature. Corresponding values for One Curve were 405.71 MPa, 472.87 MPa, and 565.17 MPa, respectively. Across all curvatures, WaveOne Gold exhibited lower stress values than One Curve.ConclusionWaveOne Gold produced lower von Mises stress values than One Curve across all tested canal curvatures. Increasing canal curvature significantly increased stress levels in both file systems.

BackgroundA three-dimensional obturation that provides a fluid tight seal of the root canal system is essential for long-term treatment success. Intracanal medicaments may hinder sealer penetration and/or affect its ability to bond with dentin. This study aimed to evaluate the sealer penetration and push-out bond strength after using Calcium hydroxide and a 2% nano-chitosan gel (CSNPs).MethodologyTwenty-four extracted single-canal lower premolars were randomly divided, according to the intra canal medicament used, into two groups: Group A, Ca(OH)2, and Group B, 2% CSNPs. After medication placement for 1 week, all canals were sealed with gutta-percha and AH Plus sealer, mixed with 0.1% fluorescent Rhodamine B isothiocyanate. Sealer penetration was evaluated with confocal laser microscopy and then push-out bond strength was measured for both groups.ResultsFor both groups, push-out bond strength varied significantly across root thirds (p < 0.001), with higher bond strength in the coronal third. The penetration radius values were significantly greater in the CSNPs group at all root levels (p ≤ 0.001). At the same time, no significant differences were found between groups or among root thirds in terms of penetration area ( p > 0.05).ConclusionsBoth Ca(OH)2 and CSNPs showed comparable push-out bond strength along the root sections, with deeper, more uniform sealer penetration with CSNPs.Clinical relevanceClinically, the choice between Ca(OH)2 and CSNPs should be guided by treatment objectives as both medicaments give comparable bond strength, while CSNPs offer advantages for deeper and more uniform tubular penetration.

A comprehensive understanding of both the external and internal anatomy of teeth is fundamental for the effective diagnosis and management of pulp and periapical pathoses. Recent progress in noninvasive, high-resolution imaging modalities, including cone-beam computed tomography and micro-computed tomography, has significantly enhanced the ability to examine the complex morphology of dental structures. These technological advancements have facilitated a level of anatomical detail that was previously unattainable, particularly in the assessment of crown, root, and canal systems. In response to this wealth of new anatomical data, a novel classification framework has been developed, enabling the systematic coding of root and canal configurations across all tooth types. This system offers a more nuanced and comprehensive representation of root canal anatomy compared to earlier classification models. This narrative review explores the implementation of this contemporary classification scheme in education, with a particular focus on its utility in recognizing anatomical variations and accessory canals for the benefit of undergraduate and postgraduate dental students as well as general dental practitioners.

Adequate irrigant penetration into dentinal tubules is essential for effective root canal disinfection, especially in anatomically complex areas of root canal system. Delivering irrigants into dentinal tubules, particularly in apical third, is frequently not possible with conventional needle irrigation. To improve irrigant penetration, irrigant activation methods such as passive ultrasonic and diode laser activation have been proposed. Super-oxidized water has shown potential as a less cytotoxic substitute irrigant for sodium hypochlorite; however, there is still little evidence on how well it penetrates dentinal tubules when used in conjunction with activation methods. This study used a diode laser and ultrasonic activation to assess and compare penetration of sodium hypochlorite and super-oxidized water into dentinal tubules. Sixty extracted human single-rooted permanent teeth with closed apices were utilized in this in-vitro study. Based on type of irrigant (5.25% sodium hypochlorite or super-oxidized water) and activation method (conventional needle irrigation, passive ultrasonic activation or diode laser activation), specimens were randomly allocated into 6 groups. 0.1% Rhodamine-B dye was used to label irrigants. Teeth were sectioned at coronal, middle, and apical levels following standardized canal preparation and irrigation protocols. Dentinal tubule penetration was measured using confocal laser scanning microscopy. Two-way ANOVA and repeated-measures ANOVA followed by Bonferroni-adjusted post hoc analysis were used for statistical evaluation, with p < 0.05 considered statistically significant. Compared to conventional needle irrigation, activated irrigation resulted in significantly increased dentinal tubule penetration. Across all canal levels, diode laser activation showed the highest penetration, followed by passive ultrasonic activation. Conventional irrigation showed the lowest penetration. Penetration decreased from coronal to apical third in every group. Super-oxidized water demonstrated dentinal tubule penetration similar to sodium hypochlorite when used in conjunction with activation procedures; under activated conditions, there was no statistically significant difference between two irrigants. Regardless of irrigant utilized, irrigant activation is essential for enhancing dentinal tubule penetration. The most successful method was diode laser activation, which was followed by passive ultrasonic activation. Super-oxidized water showed penetration comparable to sodium hypochlorite when activated, suggesting its potential for further investigation as an alternative irrigant under activated irrigation conditions.

Pulpectomy is the standard treatment for irreversibly inflamed or infected primary molars. It depends on effective root canal cleaning and shaping. Traditional manual preparation and irrigation techniques face challenges when dealing with complex root canal systems in primary teeth. This study aims to retrospectively evaluate the clinical and radiographic outcomes of two rotary nickel-titanium file systems with distinct tapers (M3 and S3) combined with ultrasonic irrigation, compared to conventional manual K-files and syringe irrigation,inpulpectomy for primary molars. A retrospective cohort study included patients aged 4- to 9-year who underwent RCT for mandibular primary molars at the Pediatric Dentistry Clinic of the Third Hospital of Hebei Medical University. Participants were categorized into three groups based on the instrumentation and irrigation protocol used: M3 rotary files with ultrasonic irrigation (n=98), S3 rotary files with ultrasonic irrigation (n=84), and manual K-files with syringe irrigation (n=78). Instrumentation time was measured using a digital stopwatch. Obturation quality was radiographically classified as optimal, underfilled, or overfilled. Postoperative pain was assessed at 24-, 48-, and 72 h using the Wong-Baker FACES scale. Clinical and radiographic outcomes at the 12-month follow-up were categorized as success, uncertain, or failure. The M3 rotary group showed the shortest instrumentation time (210.45 ± 6.85 s) and the highest rate of optimal obturation (87.1%), significantly outperforming the S3 and manual file groups (P<0.05). Both rotary systems led to significantly lower pain scores at 24 and 48 hours compared to manual instrumentation (P<0.01). No significant differences were observed in pain at 72 hours or in 12-month therapeutic success rates among the groups (P>0.05). This study demonstrates that combining modern NiTi rotary instrumentation (specifically the 0.04 tapered M3 system) with ultrasonic irrigation significantly outperforms conventional manual techniques in operative efficiency, obturation quality, and postoperative pain control. The integration of NiTi and ultrasound translates into a clinically superior, patient-beneficial protocol for primary teeth pulp therapy, optimizing procedural experience without compromising therapeutic success.

Complete removal of organic tissue and microorganisms from the root canal system is essential for successful endodontic therapy. Sodium hypochlorite (NaOCl) remains the gold standard irrigant for its tissue-dissolving and antimicrobial properties, but its cytotoxicity and adverse effects have encouraged exploration of safer herbal alternatives. Calotropis gigantea (milkweed) latex contains proteolytic enzymes such as calotropin and calotoxin, which may offer effective organic tissue dissolution with improved biocompatibility. To evaluate and compare the tissue-dissolving potential of C. gigantea latex at two concentrations (5 and 10%) with 5.25% NaOCl at different exposure times. An in vitro experimental study was conducted on pulp tissues extracted from freshly removed human teeth (n = 30). Samples were equally divided into three groups: 5% C. gigantea latex, 10% C. gigantea latex, and 5.25% NaOCl. Tissue samples were immersed for 10 minutes and 15 minutes, and weight reduction was measured using an analytical balance. Data were analysed using one-way analysis of variance and Tukey's post hoc test with a significance level of p < 0.05. The mean initial tissue weights were comparable among groups (p = 0.656). After 10 minutes, significant differences in weight reduction were observed (p < 0.001). Tukey's post hoc test showed that 10% C. gigantea latex dissolved significantly more tissue than both 5% latex and NaOCl (p < 0.001). After 15 minutes, this difference persisted (p < 0.001). The 10% latex achieved the highest mean weight loss at both intervals, while no significant difference was observed between 5% latex and NaOCl. The 10% C. gigantea latex solution showed higher tissue-dissolving ability compared to 5.25% NaOCl under static in vitro conditions. Clinical applicability requires further evaluation of activation methods, cytotoxicity, dentin interaction, and antimicrobial efficacy.

Physics-guided networks for probabilistic hydrodynamic forecasting in canal systems

Biological invasions by free-floating macrophytes are emerging as a major threat to lowland freshwater systems in Central Europe, particularly where thermally influenced canal networks create novel habitat conditions. Here, we provide the first detailed account of the distribution, habitat characteristics, and reproductive performance of Pistia stratiotes along the Élővíz Canal system near Békés and Békéscsaba (SE Hungary), situated close to the northern margin of the species' European range. In September 2022, we surveyed 71 sampling points along the canal and its tributaries; P. stratiotes was recorded at 35 sites (49.3%; Table1). Sampling locations where P. stratiotes was not detected are provided in TableS1. Occupied localities were characterised by chemically relatively homogeneous, strongly alkaline waters (pH 9.28-9.69) with low to moderate conductivity and slow flow (0.05-0.32 m s-1). Drift counts revealed that higher current velocities substantially enhanced downstream transport of rosettes, indicating that flow-mediated dispersal is a key mechanism of spread within the canal network. Of 126 individuals examined, 12.7% were flowering. Reproductive plants had markedly larger leaves and produced significantly more vegetative ramets than non-flowering individuals, suggesting a size-dependent threshold for sexual reproduction coupled with enhanced clonal propagation under favourable conditions. Our findings demonstrate that partially thermally influenced lowland canals can support persistent P. stratiotes populations under temperate climatic conditions and may potentially act as invasion hubs, although this role was not explicitly tested in the present study. These systems, therefore, warrant priority for monitoring and early management interventions.

Accurate determination of the working length is critical for the success of root canal treatment, as it ensures effective cleaning, shaping, and obturation of the root canal system. Electronic apex locators are widely used for this purpose; however, their accuracy may be influenced by intracanal conditions, particularly the presence or absence of irrigation solutions. This study aimed to evaluate and compare the accuracy of a third-generation apex locator under dry, normal saline, and 3% sodium hypochlorite canal conditions. This in vitro study was conducted on 45 extracted human single-rooted teeth randomly divided into three groups (n = 15 each) based on canal conditions: dry, normal saline, and 3% sodium hypochlorite. The actual working length (AWL) was determined visually and was used as the gold standard. The electronic working length (EWL) was measured using a Root ZX Mini. The difference between the EWL and AWL was calculated. Data were analyzed using one-way analysis of variance (ANOVA) followed by Tukey's post-hoc test, and categorical accuracy was assessed using the chi-square test, with significance set at p < 0.05. The normal saline group demonstrated the lowest mean deviation (0.21 ± 0.14 mm; 95% CI: 0.13-0.29), followed by the sodium hypochlorite group (0.34 ± 0.19 mm; 95% CI: 0.23-0.45), while the dry canal group showed the highest deviation (0.58 ± 0.22 mm; 95% CI: 0.46-0.70). A one-way ANOVA revealed a statistically significant difference between the groups (F = 18.74, p < 0.001). Post hoc analysis revealed significant differences between all groups (p < 0.05). The proportion of accurate measurements (±0.5 mm) was highest in the normal saline group, followed by the sodium hypochlorite and dry canal groups, although the chi-square test was not statistically significant (p = 0.071). Intracanal conditions significantly influenced the apex locator accuracy. Normal saline provided the most accurate measurements, whereas the dry conditions showed greater variability. Maintaining a moist canal environment may enhance clinical reliability.

Dens invaginatus (DI) is a developmental anomaly characterized by the invagination of enamel and dentin into the pulp space, predisposing affected teeth to pulpal and periapical pathologies. The complex and irregular canal anatomy often complicates endodontic management. This case report describes the nonsurgical endodontic retreatment of a maxillary lateral incisor (22) with Oehler's Type II DI in a 32-year-old female patient presenting with chronic apical periodontitis. Cone beam computed tomography revealed a highly complex root canal anatomy, consisting of a large, irregular main canal, numerous fine accessory canals, and multiple foramina associated with an extensive latero-radicular lesion. Treatment was performed under magnification and rubber dam isolation. The preexisting obturation material and part of the distal wall of the invagination were selectively removed to gain access to the root canal system. Owing to the inaccessibility of the true canal for mechanical instrumentation, disinfection was achieved exclusively through sonically activated irrigation. To manage the anatomical complexity, a novel dual-viscosity calcium silicate-based obturation technique was used, consisting of a low-viscosity tricalcium silicate sealer (BioRoot RCS), followed by incremental compaction of a high-viscosity tricalcium silicate cement (Biodentine). This approach aimed to allow the high-viscosity cement to obturate the large, irregular main canal while simultaneously driving the sealer into canal irregularities and accessory canals through the hydraulic pressure generated during its condensation. Clinical and radiographic follow-up at 18 months demonstrated evidence of periapical healing, supporting the success of the approach.