Journal of endodontics最新文献

Introduction: Advanced irrigation plays a crucial role in nonsurgical retreatment cases, as these procedures require the removal of existing obturation materials while preserving dentin. The aim of this study was to compare the effectiveness of laser-activated versus sonic-activated irrigation in removing residual obturation material in the mesial canals of mandibular molars with isthmuses during nonsurgical root canal retreatment.

Methods: Forty mesial canals of extracted mandibular molars were instrumented and obturated with gutta-percha and a bioceramic sealer. Retretments was performed using rotary instruments, followed by a final irrigation protocol consisting of 2.5% NaOCl, 17% EDTA, and a final rinse of 2.5% NaOCl using either sonic-activated or laser-activated irrigation (LAI). Micro-computed tomography scans were obtained before and after final irrigation. The volume of obturation material was measured to calculate the median percentage of remaining material in each group.

Results: The LAI group showed a significantly lower median percentage of remaining filling material than the sonic group (73.9% vs. 93.8%, P = .0165). However, neither irrigation protocol completely eliminates residual obturation material from the canals.

Conclusion: LAI was more effective at removing remaining obturation material compared to sonic-activated irrigation.

Introduction: In early stages of cracked teeth, pulpal inflammation is considered reversible. Cracked teeth with retained pulp vitality demonstrate higher survival rates whereas root canal treatment (RCT) negatively influences survival outcomes. The clinical challenge lies in discerning when RCT is required. This study aimed to develop and validate machine learning (ML) models for predicting pulp survival in cracked teeth with reversible pulpitis and investigating associations between patient- and tooth-related variables and treatment outcomes.

Methods: Data from 569 patients with 593 cracked teeth were analyzed using Logistic Regression, Gaussian Processes, Random Forests and Gradient Boosting. Input features included age, gender, tooth type and preoperative restorative material. The binary outcome represented pulp survival. A 10-fold stratified nested cross-validation approach was used: the outer loop estimated model performance and the inner loop optimized hyperparameters. Classification thresholds were tuned for probabilistic models. Performance metrics included AUC, F1-score, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

Results: Logistic Regression achieved the highest AUC (0.64) and F1-score (0.60), with strong PPV (0.76) and moderate NPV (0.48), indicating effective identification of patients requiring RCT. Other models showed similar but slightly lower performance (PPV: 0.74-0.77; NPV: 0.45-0.47). Significant predictors of pulp survival included age and presence of preoperative restorations. Older patients and those with existing restorations were less likely to require RCT.

Conclusion: ML models demonstrated a predictive accuracy of 74-77%. They could improve diagnostic precision and support timely decision-making for endodontic intervention in the management of cracked teeth with reversible pulpitis.

Introduction: This study assesses whether variations to cone-beam computed tomography (CBCT) slice thickness (ST) effect the detection accuracy and volume assessment of periapical lesions.

Methods: Forty periapical lesions were assessed on CBCT reconstructions with 0.125-mm, 0.25-mm, 0.50-mm, 1.00-mm, 1.50-mm, and 2.00-mm ST. Mimics Research was used to perform the semi-automatic segmentation technique to determine periapical lesion volume and CBCT periapical volume index (CBCTPAVI) score on each CBCT reconstruction. Diagnostic accuracy was assessed by determining the percentage of lesions detected on each reconstruction, and the Friedman test was conducted to assess for significant differences in lesion volume between the different CBCT reconstructions. Differences among CBCTPAVI scores were also assessed.

Results: Periapical lesion volume was significantly underestimated on CBCT reconstructions with ST above 1.00 mm. Variations in periapical lesion volume were the greatest among smaller lesions resulting in false negative diagnoses with the utilization of CBCTs with ST above 0.50 mm.

Conclusions: Variations in CBCT ST can significantly influence measured periapical lesion volume, and failure to account for this may lead to misinterpretation of lesion progression or healing. A minimum ST of 0.50 mm was required for the reliable detection of all periapical lesions, and this threshold serves as a benchmark for optimizing CBCT acquisition protocols to preserve diagnostic accuracy while minimizing radiation exposure.

Introduction: There is a need for safe and potent antibiofilm agents for root canal irrigation. The aim of this study was to investigate the antibiofilm activity of enzymatic irrigants (Bromelain and Papain) and their cytocompatibility to mammalian cells.

Methods: Biofilms of Enterococcus faecalis were developed on dentin discs and treated with 0.05% bromelain, 4% papain, 2.5% sodium hypochlorite (NaOCl) or saline for 15 min. The antibiofilm effectiveness was characterized by quantifying the colony forming units (CFU) and confocal microscopic examination of the bacterial cells (live/dead staining) and extracellular matrix polysaccharide using a selective fluorophore binding assay. Cytotoxicity of 0.05% bromelain, 4% papain and 2.5% NaOCl to human periodontal ligament fibroblasts was investigated using a metabolic activity assay. Data were analyzed using analysis of variance and nonparametric tests, with significance set at P < .05.

Results: Papain (4%) and Bromelain (0.05%) demonstrated 5 log CFU reduction, which was comparable to 2.5% NaOCl (P > .05). Confocal microscopy further confirmed that bromelain, sodium hypochlorite, and papain caused significantly greater bacterial cell death compared to saline (P < .05). Papain significantly reduced the extracellular matrix polysaccharide content within the biofilm compared to all other groups (P < .05).

Conclusion: This study demonstrated that bromelain and papain showed comparable antibiofilm activity as 2.5% NaOCl and were more biocompatible than NaOCl, highlighting their potential to be developed as root canal irrigants.

This case report describes the extraction of 3 mandibular posterior teeth (teeth #19, 20 and 21) with extensive invasive external cervical resorption (ECR) followed by guided double auto-transplantation of immature mandibular third molars (teeth #17 and 32). A 17-year-old male with a history of orthodontic treatment reported with intermittent pain in the mandibular left posterior region. Clinical and radiographic examination revealed extensive tooth tissue loss in teeth #19, 20 and 21 that was diagnosed as class 3 ECR (Patel 3Dp for teeth #20 and 21, 3Bp for tooth #19). Guided double auto-transplantation of the immature molar tooth #17 was performed to replace premolar teeth 20 and 21, and tooth #32 to replace tooth #19. At the 6-month follow-up the donor tooth #32 had symptoms of pulpitis and was managed with a full pulpotomy using tricalcium silicate cement. Both teeth were followed-up for 36 months when they were asymptomatic, had no associated periodontal defects, had positive pulp sensibility tests as well as radiographic evidence of substantial periapical bony healing. The roots of tooth #17 had only a limited increase in length, with apical hard tissue barrier deposition, whereas tooth #32 (after pulpotomy) had continued root development. The 36 months follow-up of this case highlights the success of an interdisciplinary approach when integrating three-dimensional guides for double auto-transplantation of immature molars to successfully replace multiple teeth with extensive invasive ECR.

Introduction: The purpose of this study was to evaluate long-term outcomes of nonsurgical retreatment (NS-ReTx) procedures performed by a single endodontist in private practice.

Methods: This retrospective cohort study evaluated NS-ReTx procedures performed between the years 1986 and 2019, meeting the following inclusion criteria: minimum of 1-year follow-up and preoperative, postoperative, and follow-up radiographs available for analysis. Procedures were evaluated clinically and radiographically, and treatment outcomes were reported. A subset of cases included cone-beam computed tomography (CBCT) images and CBCT-assessed periapical healing was reported for these cases. The effect of clinical factors on radiographic healing was assessed using a Cox proportional hazard regression model. The Kaplan-Meier method estimated the probability of tooth survival at each year of follow-up.

Results: A total of 241 NS-ReTx procedures from 202 patients met the inclusion criteria. The median patient age at time of NS-ReTx was 54 years. Molars were the most frequently treated tooth type, 57.68%. Radiographic healing at the median follow-up time, 9.14 years (n = 231) was 64.07% healed (148 of 231), 7.36% healing (17 of 231), and 28.57% unhealed (66 of 231). An additional 10 teeth were extracted before any radiographic follow-up. CBCT-assessed periapical healing ("strict" criteria) was 65.63% over a median follow-up time of 9.18 years. Tooth survival following NS-ReTx was 93.3% at 5 years and 85.3% at 10 years.

Conclusions: The study demonstrates that radiographic periapical healing and treatment success improve over time and that tooth survival following NS-ReTx is favorable long-term.

Introduction: Mineral trioxide aggregate is widely used for apexification in immature permanent teeth owing to sealing ability and biocompatibility; however, placement in teeth with open apices may result in void, potentially compromising the apical seal. This study compared mineral trioxide aggregate (MTA) apical plug quality and procedural time among 3 placement techniques.

Methods: Thirty extracted human mandibular premolars with simulated open apices (apical diameter, 0.8 mm) were randomly assigned to 3 groups (n = 10). Four-millimeter MTA apical plugs were placed using manual condensation, indirect ultrasonic activation, or sonic-activated rotary compaction. Micro-computed tomography quantified closed porosity (internal voids) and open porosity (interfacial gaps) as percentages of total apical plug volume. Procedural time was recorded, and data were analyzed statistically.

Results: Sonic-activated rotary compaction produced the lowest open porosity (0.001% ± 0.001%) and shortest procedural time (160.00 ± 6.50 s) but resulted in the highest closed porosity (0.412% ± 0.076%). Manual condensation demonstrated the highest open porosity (0.122% ± 0.063%) and moderate closed porosity (0.108% ± 0.076%), whereas indirect ultrasonic activation showed intermediate open porosity (0.006% ± 0.002%) and lowest closed porosity (0.079% ± 0.030%). Importantly, closed porosity did not differ significantly between the manual and ultrasonic groups (P = .523). Indirect ultrasonic activation required the longest procedural time (270.30 ± 7.27 s), followed by manual condensation (229.20 ± 6.34 s), whereas sonic-activated rotary compaction was the most time-efficient. All other intergroup differences were statistically significant (P < .001).

Conclusions: Sonic-activated rotary compaction demonstrated the lowest open porosity and greatest time efficiency among 3 techniques, although it produced the highest closed porosity.

Introduction: This study aimed to investigate how substrate stiffness and dimensionality regulate stemness, senescence, and subsequent odontogenic differentiation in dental pulp stem cells (DPSCs). It further examines the interplay of priming period and odontogenic induction and elucidates the role of NF-κB signaling in this process.

Methods: Mechano-variant PDMS substrates with tunable stiffness (2kPa to 50kPa) were fabricated for 2D and 3D cultures. DPSCs were primed on these substrates for 7 days and subsequently induced for odontogenesis. Analyses included gene expression, immunofluorescence imaging, and matrix mineralization.

Results: The 2kPa substrates significantly enhanced early odontogenic differentiation, evidenced by upregulation of DMP-1 and DSPP, along with higher expression of stemness markers (NANOG, SOX-2). This condition minimized senescence and promoted mixed nuclear and cytoplasmic NF-κB localization, suggesting a priming effect for efficient differentiation. In contrast, 3D substrates exhibited delayed but robust odontogenic responses, coupled with increased epigenetic regulation (HAT-1, HDAC-1) and elevated XRCC5 expression at day 21, indicating active DNA repair and intermediate senescence levels that stabilized over time.

Conclusions: Soft substrates (2kPa) preserve stemness and promote early differentiation, while 3D environments favor late-stage differentiation and balanced senescence. These findings emphasize the importance of priming period and dimensionality in optimizing MSC-based regenerative therapies.

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.