Journal of endodontics最新文献

Introduction: Laser activated irrigation (LAI) has enhanced the cleaning and disinfection of root canals. However, limited evidence exists regarding its effects on dentin's structural integrity. Although proven to enhance cleaning and disinfection results, it was anticipated that LAI use may alter the root dentin surface due to thermal effects.

Methods: Forty-two single-rooted human premolars were instrumented and randomly divided into 3 groups: A) control group (n = 14) no laser treatment; B) irrigant activation using diode laser (980 nm, 10 Hz, 200 μm, 21 mm) (n = 14); and C) irrigant activation using Er,Cr:YSGG laser (2940 nm, 25 mJ, 10 Hz, 60 μs 200 μm, 21 mm) (n = 14). The root canal dentin samples were subjected to scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy (FTIR), and nanoindentation analysis. Sample size was calculated using G∗Power, and data were statistically analyzed using one-way ANOVA and post hoc Tukey tests through SPSS software (IBM Corp. IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY).

Results: FTIR analysis of diode-treated dentin revealed structural degradation with new hydroxyl groups (3829.74, 3744.47 cm^-1) and strong carbonyl peak (1741.30 cm^-1). FTIR compositional analysis showed destruction of amide (collagen), phosphate, and carbonate contents in laser groups. Elemental analysis showed significantly increased Ca and P peaks. Structural examination revealed excessive thermal-stress-induced cracking in the diode group and moderate cracking in Er,Cr:YSGG group. Mean hardness (HIT, HVIT) and elastic modulus differed significantly between control and both laser groups. Traditional root canal disinfection produced minimal structural damage across all analyses.

Conclusions: LAI significantly altered the tested properties of root dentin. Er,Cr:YSGG showed comparatively lesser structural damage than diode laser based irrigant activation.

Introduction: The aim of this study was to compare the biomechanical effects of mineral trioxide aggregate (MTA) and Biodentine for repairing root perforations in conjunction with 2 obturation strategies (complete versus partial gutta-percha obturation) on the fracture resistance of maxillary first premolars. The incidence of these treatment modalities on the probability of fracture risk was evaluated quantitatively.

Methods: Seven three-dimensional finite element models were constructed from cone-beam computed tomography data. The tooth models that were used consisted of a sound tooth model (SD), a root canal-filled model, an unrepaired perforation model, and four treatment models consisting of MTA/Biodentine combined with complete (All GP) or partial gutta-percha obturation being Part GP. The stress distribution under a 300 newton (N) occlusal load was then analyzed, and the fracture probability (P_f) was assessed using a Weibull analysis over a load range of 0-600 N.

Results: Under a 300 N load, the unrepaired perforation model showed a significantly higher P_f (10.15%), which was 10.6 times greater than SD's. All treatment models restored dentin stress to near-SD levels (9.71-10.01 MPa). When combined with the All GP strategy, both MTA and Biodentine achieved P_f values comparable to root canal-filled model (2.84% at 300 N). In contrast, the Part GP strategy resulted in higher stress values in the coronal enamel and midroot dentin, and higher P_f values (3.24%-3.99% at 300 N).

Conclusion: Both MTA and Biodentine are effective at restoring the biomechanical performance of perforated teeth. The obturation strategy significantly influences the long-term fracture risk. The All GP strategy combined with either repair material optimizes fracture resistance and minimizes failure risk. As a result, it is recommended as the preferred clinical technique.

Introduction: This study aimed to evaluate the impact of mineral trioxide aggregate (MTA)- and putty-based regenerative and one-step apexification protocols on the fracture strength and failure patterns of immature teeth.

Methods: Seventy-two extracted human maxillary central incisors were decoronated and prepared to simulate immature root morphology. The samples were randomly divided into 8 groups (n = 10): negative control (sound teeth), positive control (simulated immature teeth with no intervention), full MTA, full putty, apical MTA barrier + warm vertical compaction (WVC), apical putty barrier + WVC, regenerative MTA, and regenerative putty groups. After material placement and restoration, all specimens were embedded in acrylic blocks and loaded at 135° to the long axis using a universal testing machine at a crosshead speed of 0.5 mm/min until fracture occurred. The maximum load at fracture (N/cm) and fracture location (above or below the cementoenamel junction) were recorded. Data were analyzed using the Kruskal-Wallis and Dunn tests, Fisher's exact test, and Weibull analysis (P < .05).

Results: Significant differences in fracture strength were observed among the groups (P < .05), whereas fracture location did not differ significantly (P > .05). The lowest mean fracture strength was found in the regenerative putty group, while the full MTA group exhibited the highest values. Weibull analysis revealed no significant difference in the shape parameter (P = .108), but the scale parameter differed significantly among the groups (P < .001), confirming greater reliability and characteristic strength in MTA-based protocols.

Conclusions: Filling immature roots entirely with MTA or using an apical MTA plug followed by WVC provided superior and more consistent fracture resistance compared with putty-based regenerative protocols. Bioceramic putty may not be a good choice for regenerative applications when the reinforcement of immature teeth is desired.

Objective: To compare intraorifice barrier materials for reinforcing endodontically treated teeth using a network meta-analysis of in vitro studies.

Methods: EBSCO, PubMed, Virtual Health Library, Ovid, Web of Science, Scopus, Cochrane Library, and Google Scholar were searched to December 2025. Eligible studies compared at least 2 of the following: alkasite restorative material, composite resin, fiber-reinforced composite (FRC), resin-modified glass ionomer cement (RMGIC), flowable composite, Biodentine, mineral trioxide aggregate (MTA), and control. The primary outcome was fracture resistance (Newtons). The analysis was conducted in MetaInsight v6.4.0 (Complex Reviews Synthesis Unit, NIHR (Evidence Synthesis Group, University of Glasgow), Glasgow, United Kingdom) using its Bayesian option; results are reported as 95% credible intervals (CrIs). Treatment hierarchy was summarized with SUCRA. Small-study effects were assessed with funnel plot and Egger's test.

Results: Twenty studies met the eligibility criteria; 14 contributed to the network meta-analysis. Versus control, fracture resistance increased with alkasite restorative material (MD 406.37; 95% CrI 133.4-679.8), FRC (MD 370.83; 95% CrI 168.82- 574.27), composite resin (MD 360.62; 95% CrI 181.92-555.15), RMGIC (MD 310.82; 95% CrI 180.93-449.62), flowable composite (MD 285.5; 95% CrI 107.79-468.35) and Biodentine (MD 230.83; 95% CrI 66.55-401.34). MTA showed no clear benefit (MD 60.41; 95% CrI -123.08- 242.82). SUCRA ranking favored alkasite restorative material, followed by FRC, composite resin, RMGIC, flowable composite resin, Biodentine, MTA, and control. Node-split analyses indicated some local inconsistency across a subset of contrasts (2 of 28 contrasts; minimum P = .003). Funnel-plot inspection and Egger's test did not suggest small-study effects (P = .664).

Conclusions: Use of an intraorifice barrier generally improves the fracture resistance of endodontically treated teeth. Materials traditionally categorized as restorative materials (alkasite, resin composites, FRC, and RMGIC) tended to rank higher than calcium silicate-based barriers (Biodentine, MTA) in vitro. Standardized testing protocols are needed to optimize material selection.

The dental pulp is a highly vascularized and innervated connective tissue located at the central part of the tooth and composed of a diverse array of cell types, including fibroblasts, multipotent mesenchymal stem cell, odontoblasts, and immune cells. Traumatic injuries and carious lesions can lead to dental pulp pathologies that often require replacement of damaged tissue with inert materials. Despite significant progress in recent years, cell-based dental pulp regenerative therapies remain distant from clinical applications. The lack of platforms capable of accurately modeling the human dental pulp in all its complexity hampers the development of novel therapeutic strategies. In response, numerous efforts have been focused on the development of innovative microfluidic systems designed to emulate human dental pulp physiology. These "dental pulp-on-chip" platforms enable the recreation of structural and functional complexity in an in vivo-like environment, opening new horizons for patient-specific endodontic therapies and providing valuable tools for targeted drug testing. This review focuses on state-of-the-art microfluidic devices designed to emulate the dental pulp and their specific applications in dental materials testing, drug evaluation, and pulp regeneration. By integrating multiple cell types, biomaterials, and bioactive cues within dynamic microenvironments, "dental pulp-on-chip" devices overcome the constraints of traditional in vitro cultures and animal models and enable the assessment of treatment-induced systemic effects, an aspect often overlooked in dental research. Continued advancements in "dental pulp-on-chip" technology will be pivotal for bridging preclinical research and clinical practice in dental medicine.

Introduction: Endodontic kinematics are associated with varying levels of inflammatory response and postoperative pain. The effect of apical motion algorithms in integrated endodontic motors on this relationship has not been clinically evaluated. This study aimed to evaluate the effects of root canal preparation with continuous rotation (CR) and 2 different apical action algorithms on periapical inflammation mediator and patient-reported pain outcomes.

Methods: Sixty-six patients with asymptomatic pulpitis, symptomatic irreversible pulpitis, and normal pulps to be exposed for prosthetic preparation requiring endodontic treatment were randomly assigned to three groups: CR, auto apical reverse (AAR) and auto apical slow-down. Root canal instrumentation was performed and apical exudate samples were collected on postoperative Days 0 and 3 are analyzed for inflammatory mediators, including substance P (SP), tumor necrosis factor-α, interleukin-1β and interleukin-6. Preoperative and postoperative Day 3 visual analog scale pain scores were recorded.

Results: SP levels on Day 0 (P < .001) and Day 3 (P = .001) were significantly higher in the AAR group. No significant differences were found between the groups regarding postoperative pain scores. When cytokines were assessed in terms of percent change, only tumor necrosis factor-α showed a significant increase in the auto apical slow-down group compared to the CR group (P = .035).

Conclusion: This study demonstrated that different apical actions influence the levels of inflammatory mediators in periapical tissues. AAR was found to be associated with higher SP release on both sampling times. However, the variations in mediator levels didn't translate into differences in pain outcomes. Further research is needed to clarify the effects of apical actions on inflammation, pain, and overall clinical outcomes.

Introduction: To investigate the geometric angle method of "danger zone" (DZ) position in the mesial roots of mandibular first molars (MFMs) using cone-beam computed tomography (CBCT) and micro-computed tomography (Micro-CT).

Methods: The CBCT images of 949 MFMs with mesial roots of single root and 2 root canals were collected and analyzed with DZ and α_D (the angle between the line extending from the center of buccal/lingual root canal to DZ and the line connecting the centers of the buccal and lingual root canals) of the mesial roots in the coronal and middle thirds of roots. Thirty-four MFMs with similar root canal morphologies were analyzed using Micro-CT to validate the geometric positioning method based on CBCT. The association of α_D with the root lengths, inter-orifice canal distance (D_R-R), age and gender were subsequently investigated. Values with P < .05 were considered statistically significant.

Results: The DZ of MFMs was mainly located in the middle thirds of the distal wall, with an average thickness of 0.818 ± 0.143 mm. The average α_D was 71.9 ± 9.0°, ranging from 42.7° to 99.9° and showed approximately 87.8% of value concentrated within the range of 60.1°-86.2°. The α_D was negatively correlated with the D_R-R (P < .01) and had no correlation with age or gender (P > .05). Results of the Micro-CT analyses showed that the α_D was 70.4 ± 7.3°, ranging from 48.9° to 85.6°, and 92.7% of the α_D were also within the range of 60.1°-86.2° established by CBCT.

Conclusions: From a geometric perspective, the distribution of DZ in the mesial roots of MFMs demonstrated a relatively consistent spatial pattern. This predictable localization may assist clinicians in accurately identifying DZ positions and improving treatment planning.

Introduction: This study compared the quality of placement and removal of a bioceramic intracanal medication (Bio-C Temp) and a calcium hydroxide-based medication (UltraCal XS) using micro-computed tomography (micro-CT) analysis.

Methods: Mandibular molars with Vertucci type II mesial root configuration were selected based on micro-CT evaluation. Teeth were allocated into 2 matched groups according to root canal anatomy and volume as similar as possible. Canals were instrumented using WaveOne Gold Primary files. Medications were injected into the canal using a syringe according to the manufacturer's instructions: UltraCal XS (Ultradent, USA) or Bio-C Temp (Angelus, Brazil). After 15 days, the medication was removed by using ultrasonic activation of 2.5% NaOCl. Micro-CT scans were taken after instrumentation, and medication placement and removal to quantify the canal volume and medication volume.

Results: No significant differences in medication filling or removal were observed between groups at either the 4-mm or 8-mm canal levels from the apical foramen (P > .05). After placement, Bio-C Temp filled 73% of the full canal length and 30% of the apical 4-mm segment, while UltraCal XS filled 57% and 25%, respectively. The removal protocol substantially reduced medication volumes in both groups, with mean reductions of 91.9% and 88.5% for Bio-C Temp and 82.6% and 81.3% for UltraCal XS in the full canal and apical segments, respectively. Complete elimination was observed in only a few specimens from both groups.

Conclusion: UltraCal XS and Bio-C Temp exhibited similar results in terms of placement and removal. Neither material completely filled the prepared canal, and removal with ultrasonic activation also failed to achieve complete elimination in most specimens.

Introduction: Dental pulp stem cells have been explored as a potential source for dentin-pulp complex regeneration because of their pluripotency and differentiation capacity. However, cell-based approaches require enzymatic digestion and in vitro expansion, which may alter cell properties and hinder clinical translation. This preliminary proof-of-principle study examines a tissue-based alternative using freshly minced pulp (MP) in an ectopic mouse model as a potentially translatable approach for regenerative endodontics.

Methods: Human dental pulp tissue was either minced or enzymatically digested, seeded onto collagen type I scaffolds, inserted into root fragments, and implanted subcutaneously into immunocompromised mice.

Results: Histology revealed that MP grafting generated well-organized dentin-pulp-like tissue with high cellularity, vascularization, mineralization, and odontoblast-like cells extending processes into dentinal tubules, whereas dental pulp stem cell grafts formed less organized tissue and mineral deposits. MP-derived tissues also exhibited angiogenic potential, forming vessel-like structures containing pericytes and endothelial cells.

Conclusions: This preliminary in vivo mouse study suggests the feasibility of MP transplantation and its potential for dentin-pulp complex regeneration, though further studies are needed to assess long-term outcomes and clinical applicability.