International endodontic journal最新文献

Aim

The study aims to experimentally characterize the flow inside lateral canals during ultrasonic irrigation. The effect of the canal angle as well as the relative position of the endodontic file with the inlet of the channel was quantified.

Methodology

An idealized endodontic geometry was 3D printed and used as a mould to fabricate a channel made of PEG-modified hydrophilic PDMS. The mould comprises a 20 mm tapered (6%) root canal with a 0.4 mm apical diameter and a 5 mm long lateral canal with a 200 μm square cross section, forming an angle of either 90° or 60° with the axis of the root canal and placed 6 mm from the apex. The channel was filled with a NaI-water solution and seeded with 1 μm particles. An ultrasonic instrument with a 15# K-file was employed for the irrigation. The flow field was characterized by Particle Image Velocimetry.

Results

The flow inside the lateral canals is notably affected by the position of the endodontic file. There is a competition between the impingement of the ultrasound-induced jets on the walls of the root canal and the recirculation flows around the file, leading to either flow into the lateral canal or suction phenomena that generate backflow towards the root canal. Aligning the jet with the axis of the lateral canal maximizes the magnitude of the velocities that can be achieved therein. This alignment can only be achieved in the 90° channel. Inclining the lateral canal to 60° leads to lower velocities and a domination of the backflows towards the root canal. In both cases, a recirculation zone forms near the inlet of the channel where transverse velocities are comparable with the axial ones. The recirculation zone length is affected by the inclination of the channel. Further inside the canal, the flow becomes uniaxial.

Conclusion

The flow during ultrasonic irrigation inside lateral features of the root canal is complex and considerably affected by the position of the endodontic file and the inclination of the channel. An optimum location of the file tip leads to maximization of the induced velocity inside the lateral canal, suggesting more effective cleaning.

Aim

A case report to describe the use of a novel 3D printed surgical decompression device to induce healing of large periapical lesions.

Summary

The development of periapical pathology is influenced by a variety of factors including local microbiology and pathophysiology. In large lesions, lone orthograde endodontic treatment is often insufficient in promoting healing of the periapical tissues and therefore is followed by apical surgery to reduce inflammation. While traditional surgical treatments often involve enucleation for cystic lesions, decompression techniques have shown to provide a less invasive alternative when combined with non-surgical and/or surgical endodontic treatment.

The case presented here is a 21-year-old male with a large periapical lesion involving a root canal-treated right maxillary central incisor and nasopalatine canal; extending from the maxillary right lateral incisor to the maxillary left central incisor and having perforated buccal and lingual cortical plates. Clinically, the patient reported an associated fluctuant, non-tender buccal swelling. CBCT confirmed a well-condensed root canal filling; hence, it was decided to first treat the lesion conservatively using only the surgical decompression technique. Following a discussion about treatment options, the patient consented to surgical decompression. CBCT imaging alongside digital software was used to fabricate a customised decompression device that was sutured in situ for 4 weeks. Nine months following the removal of the device, CBCT showed evidence of osseous deposition, with a significant reduction of the periapical radiolucency and separation from the nasopalatine canal, thus portraying the use of decompression in its own right as a treatment option.

Surgical decompression is not a novel technique, and the literature describes the use of various dental equipment such as suction tubing, needle hub, or dental dam material to facilitate decompression of a lesion. These devices have, however, shown to cause irritation, discomfort, and instability and are therefore not always effective in inducing healing. This case report describes the use of a novel digital workflow to fabricate a customised decompression device in the management of a large periapical lesion. The reduction of intra-cystic pressure alongside active irrigation reduced inflammatory compounds, contributing to a reduction in the lesion size and promoting osseous healing.

Aim

This study aimed to compare the shaping ability of 3 single-file systems in flat-shaped canals.

Methodology

Thirty-six extracted mandibular incisors with flat-shaped canals were anatomically matched using micro-CT technology and assigned to three groups (n = 12) based on the single-file system used for root canal preparation: 1.5-mm SAF Infinitum, Reciproc Blue R25, or XP-endo Rise Shaper. After a new micro-CT scan, pre- and post-preparation datasets were co-registered and analysed to quantify changes in canal volume, surface area, unprepared canal areas, dentine thickness and hard-tissue debris volume. Parametric (One-way ANOVA, Student's t-test for repeated measures) and non-parametric (Kruskal–Wallis and Wilcoxon Signed Rank) tests were applied for statistical comparisons (α = 5%).

Results

All groups showed significant increases in canal volume and surface area and reductions in unprepared canal areas after each preparation step (p < 0.05), with no significant differences among SAF Infinitum, Reciproc Blue and XP-endo Rise Shaper in shaping parameters at any time point (p > 0.05). Dentine thickness significantly decreased over time in all groups (p < 0.001), except for Reciproc at the buccal pericervical region and lingual midroot (p > 0.05), with greater reductions in the lingual pericervical region (SAF Infinitum) and mesiodistal mid-root level (Reciproc Blue and XP-endo Rise Shaper) (p < 0.05). Critically thin dentine areas (< 0.5 mm) were only observed mesiodistally at the mid-root level after preparation. Hard-tissue debris volumes did not differ significantly among groups (p > 0.05).

Conclusions

SAF Infinitum, Reciproc Blue and XP-endo Rise Shaper systems provide comparable shaping performance and dentine preservation in flat-shaped canals. While all systems cause some dentine thinning, critically thin areas remained limited and localised.

Aim

To describe an unusual case of post-traumatic trigeminal neuropathy affecting an accessory canal of the canalis sinuosus related to a maxillary central incisor.

Summary

This case report presents a 48-year-old female patient who suffered from neuropathic pain following the crown placement and endodontic treatment of a left maxillary central incisor (tooth 21). A cone beam computed tomographic (CBCT) scan of the anterior maxilla revealed an accessory canal apical to tooth 21, with extruded sealer within the bony channel. A sustained resolution of the patient's symptoms was achieved following apicectomy of the tooth and surgical resection of the accessory canal. The tooth remained asymptomatic at the 5-year follow-up.

Aim

This prognostic study aims to develop a machine learning (ML) survival model for estimating the longevity (success and survival rate) of restorations in endodontically treated teeth (ETT).

Methodology

Data were consolidated from four controlled clinical trials conducted in the Netherlands and Brazil, involving 424 patients and 618 restorations with up to 17 years of follow-up. The evaluated predictive models included Gradient Boosting Survival, Random Survival Forests and Survival Support Vector Machine. The dataset was split into 70% for training and 30% for testing. Hyperparameter tuning was optimised via 10-fold cross-validation with 50 iterations using hyperopt. Performance was assessed through the time-dependent area under the ROC curve (AUC), concordance index (C-index), inverse probability of censoring weights (IPCW C-index) and time-dependent Brier score.

Results

The Gradient Boosting Survival model achieved the highest AUC mean (0.83, 95% confidence interval [CI], 0.81–0.78), C-index (0.80), IPCW C-index (0.78) and Brier score (0.06) for survival rate predictions, maintaining predictive stability over time. For success rate, the Random Survival Forest model outperformed others (AUC = 0.73, 95% CI [0.70–0.75]), C-index (0.66), IPCW C-index (0.64) and Brier score (0.14). SHAP analysis identified patient age and tooth type as having the highest variable importance for survival, while the dentist's experience was critical for success outcomes. Fairness analysis revealed performance disparities across sexes and countries in the models.

Conclusions

The models demonstrated high predictive performance, mainly in survival rate prediction. ML models show promise for developing a robust, data-driven framework to evaluate success and survival outcomes in ETT.

Aim

To determine whether the combined use of periapical radiography (PR) and cone beam computed tomography (CBCT) improves agreement among three endodontic experts compared with using either diagnostic tool alone.

Methodology

Sixty clinical records with CBCT scans were selected from cases performed by postgraduate and master's students in endodontics at the University of Barcelona Dental Hospital. Three endodontic experts independently evaluated each case using a standardised questionnaire. Initially, they assessed the PR images. After 4 months, they reassessed the cases using CBCT. One year later, they reviewed both PR and CBCT together. Agreement levels were analysed for pulpal and periradicular diagnoses, treatment recommendations and aetiological assessments.

Results

Inter-observer agreement improved across the study phases, peaking in phase 3—particularly for treatment recommendations. In this final phase, where both PR and CBCT were evaluated together, the agreement rate for pulpal diagnosis was 73.33%, with substantial reliability (κ = 0.67). Periradicular diagnosis showed a 40.00% agreement rate, with moderate inter-observer concordance (κ = 0.44). The lowest agreement was observed in the aetiology category (28.33%), with moderate concordance (κ = 0.50). Agreement on treatment recommendations reached 43.33% (κ = 0.51) and was the only category to show statistically significant differences between phases (p = 0.01). No significant differences were found for pulpal diagnosis (p = 0.39), periradicular diagnosis (p = 0.19) or aetiology (p = 0.36). Intra-observer agreement varied among experts, with some showing lower consistency in their responses when evaluating PR, CBCT and the combination of both, highlighting the influence of imaging modality on clinical decision-making.

Conclusions

The combination of PR and CBCT improved inter-observer agreement across all categories compared to the use of a single imaging modality. However, this improvement reached statistical significance only for treatment recommendations. These findings suggest that, whereas combining PR and CBCT may support more consistent therapeutic decision-making, its impact on diagnostic agreement may vary depending on the specific diagnostic domain.

Aim

To evaluate the accuracy of guided access cavity preparation in calcified canals using a robotic system, compared to static and dynamic guided methods.

Methodology

Three 3D-printed mandibular models presenting with pulp canal obliteration were allocated into three groups for robot, static and dynamic-guided access cavity preparations. The primary outcomes measured were the coronal deviation, apical deviation and angular deviation between the planned and actual paths of access cavity preparation. Additionally, all access cavities were confirmed to determine whether the canal was located. The data were analysed using the one-way analysis of variance (ANOVA), Tukey's post hoc test and multilevel linear regression models. The significance level was set at 0.05.

Results

All canals (n = 12) in the robot-guided and static-guided groups were located. In the dynamic guided group, a total of 10 out of 12 canals were found, with 2 resulting in root perforations. The accuracy of access cavity preparation using a robotic system showed no significant difference compared to the static-guided group (p > 0.05). However, the apical and angular deviation results were significantly lower in the robot-guided group than the dynamic-guided group (p < 0.05).

Conclusions

The robotic system exhibited comparable accuracy to the static guide, whereas it significantly outperformed dynamic navigation in terms of guided access cavity preparation for calcified root canals. However, further clinical studies are needed to confirm these preliminary findings.

Aim

To characterise and evaluate mucoadhesive strength and antibacterial properties of a nanotechnological formulation for endodontic disinfection based on biodegradable nanoparticles dispersed in a thermosensitive gel containing calcium hydroxide (Ca(OH)₂-NPs-gel).

Methodology

Morphology of Ca(OH)₂-NPs-gel was studied using transmission electron microscopy. Moreover, Ca(OH)₂-NPs-gel was sterilised using gamma irradiation (25 kGy), and the stability after the sterilisation process was studied by measuring Ca(OH)₂-NPs-gel average size, polydispersity index, zeta potential and encapsulation efficiency. To assess the ex vivo mucoadhesive strength, extracted single-rooted human teeth were used to measure the force necessary to separate the formulation from the teeth. In addition, the short-time stability of Ca(OH)₂-NPs-gel was evaluated monthly, analysing entrapment efficacy, backscattering and transmittance of Ca(OH)₂-NPs-gel stored at different temperatures (4°C, 25°C and 37°C). Furthermore, the antibacterial analysis of Ca(OH)₂-NPs-gel was performed against Enterococcus faecalis inoculated in extracted human single-root teeth and evaluated by confocal and scanning electron microscopy. Finally, the metabolic activity of bacteria was studied through a resazurin assay to evaluate bacterial survival after treatment.

Results

Ca(OH)₂-NPs-gel owned a round shape and a smooth surface without particle aggregation. Sterilisation did not induce an alteration in Ca(OH)₂-NPs-gel physicochemical properties and Ca(OH)₂-NPs-gel presented a high adhesion strength. In addition, 4°C was the best temperature to store Ca(OH)₂-NPs-gel. Regarding the antibacterial therapeutic efficacy, Ca(OH)₂-NPs-gel possesses suitable antibacterial properties, indicating that it efficiently reduces bacterial biofilms.

Conclusion

Calcium hydroxide-loaded PLGA nanoparticles dispersed in a thermosensitive gel have been developed, optimised and characterised, obtaining excellent antibacterial properties and achieving bacterial disinfection levels similar to those of commercial formulations.