Francesco Mannocci

Aim: The primary aim of this study was to evaluate whether the volume of residual coronal tooth structure influences the survival of root canal‐retreated posterior teeth with up to 10‐year follow‐up. Secondary aims were to assess whether 12‐month radiographic findings and the Dental Practicality Index (DPI) could predict long‐term survival. Methodology: A total of 156 posterior teeth in 140 patients underwent clinical examination, baseline CBCT and PA prior to retreatment in a postgraduate endodontic unit under specialist supervision. Residual coronal tooth volume was quantified using intraoral scans following the completion of root canal retreatment and before core build‐up and placement of metal–ceramic crowns. The metal–ceramic crowns were cemented using RelyX Luting Plus (3 M ESPE, St. Paul, MN, USA). Follow‐up assessments were conducted at 12, 24, 36, 48, and 120 months (T12–T120). Periapical radiograph (PA) and cone beam computed tomography (CBCT) were obtained at T12, with additional periapical imaging at T48. Outcomes were categorized as ‘survived’ or ‘extracted’. The optimal cut‐off value for residual volume was identified using receiver operating characteristic (ROC) analysis and Youden's index. Associations between survival and clinical variables were analysed. Results: The 10‐year recall rate was 66.4%, with a Kaplan–Meier estimated 10‐year cumulative survival of 85.4%. The optimal threshold for residual tooth volume was 41%, with 58 teeth (40.8%) below this threshold and 84 (59.2%) at or above it. Teeth with < 41% volume had an extraction rate more than three times higher than those with ≥ 41% (20.7% vs. 5.9%; p = 0.016). Teeth with an unfavourable 12‐month CBCT result had a 4.5‐fold increased risk of extraction compared to those with favourable outcomes ( p = 0.004). DPI scores were not significantly associated with extraction risk ( p = 0.67). Conclusion: Root canal‐retreated posterior teeth demonstrated favourable long‐term survival. A residual coronal tooth volume ≥ 41% was strongly associated with improved survival. In addition, favourable PA and CBCT findings at 12 months were associated with improved long‐term outcomes. These findings support root canal retreatment as a reliable and biologically favourable treatment option for posterior teeth with persistent apical periodontitis.

Background: Calcium silicate sealers (CSS) have become the dominant approach to root canal obturation in many specialist practices, yet evidence on their performance in nonsurgical retreatment is sparse and CBCT‐based assessment remains uncommon. The behaviour of a CSS‐based retreatment protocol under three‐dimensional assessment is therefore poorly characterised. Aim: To evaluate the clinical and radiographic outcomes of nonsurgical retreatment with a calcium silicate sealer using both periapical (PAI) and CBCT (CBCT‐PAI) indices, and to identify factors associated with CBCT‐assessed success. Methodology: One hundred and thirty‐six previously root canal treated teeth in 97 patients were enrolled at Jaber Al‐Ahmed Dental Center, Kuwait, between March 2023 and December 2024. A single endodontist performed retreatment using a standardised sealer‐based obturation protocol with a calcium silicate sealer (CeraSeal). Teeth were re‐examined clinically at 12–24 months. Two calibrated specialists independently scored periapical radiographs (PAI) and small‐field‐of‐view CBCT (CBCT‐PAI), classifying each tooth as Healed, Healing or Diseased under both systems to yield four endpoints (PAI‐loose, PAI‐strict, CBCT‐loose, CBCT‐strict). The CBCT endpoints were primary and PAI endpoints descriptive. Multivariable analysis used Hosmer‐Lemeshow purposeful selection with generalised estimating equations (CBCT‐strict) and Firth's penalised logistic regression (CBCT‐loose). Results: Of 136 enrolled teeth, 118 in 80 patients were re‐examined (tooth‐level recall 86.8%, patient‐level recall 82.5%, mean follow‐up 13.9 months). Success rates were 93.2% (PAI‐loose), 89.0% (CBCT‐loose), 83.1% (PAI‐strict) and 64.4% (CBCT‐strict). Each one‐point increase in pre‐operative CBCT‐PAI reduced the adjusted odds of CBCT‐strict success (adjusted OR 0.57, 95% CI 0.41–0.81, p = 0.001). Non‐molar teeth had higher odds of CBCT‐loose success than molars (OR 4.69, 95% CI 1.30–25.01, p = 0.017). A pre‐specified sensitivity analysis recoding pre‐operative CBCT‐PAI as absence (≤ 1) versus presence (≥ 2) of periapical radiolucency confirmed the CBCT‐strict finding. Conclusions: In a cohort weighted toward large pre‐operative lesions (65% at CBCT‐PAI ≥ 4), nonsurgical retreatment with a calcium silicate sealer produced outcomes at the upper end of the pooled retreatment literature under both PAI‐ and CBCT‐based assessment at 12 to 24 months. Pre‐operative lesion size was the dominant predictor of complete healing (CBCT‐strict), while tooth type was the only independent predictor of CBCT‐loose success. Trial Registration: This study was registered on ClinicalTrials.gov (identifier NCT05714384)

Background: Nickel-titanium (Ni-Ti) endodontic files are revolutionizing root canal therapy because of their remarkable flexibility, shape memory, and corrosion resistance. Nonetheless, cyclic fatigue, corrosion-related fractures, and biofilm development have restricted their clinical efficacy. Recent developments in nanotechnology provide solutions using surface coatings with nanoparticles to enhance the mechanical, chemical, and biological properties of Ni-Ti alloys. Materials and Methods: Current developments in nanoparticle coatings for Ni-Ti alloy are investigated in this narrative study. Of the 57 papers generated from a preliminary literature assessment, only 10 fit the inclusion criteria for relevance, approach, and scientific interest. Results: The selected studies highlight a spectrum of nanoparticles: Titanium dioxide (TiO₂), Zirconia (ZrO₂), Silver (Ag), Silicon carbide (SiC), Graphene oxide (GO), Hydroxyapatite (HA), Carbon nanotubes (CNTs), and Fullerene-like tungsten disulfide (IF-WS₂). Fatigue resistance, wear resistance, corrosion resistance, and antibacterial properties of Ni-Ti alloy coated with these nanoparticles have shown significant development. These coatings not only extend the lifetime of Ni-Ti alloy but also reduce bacterial colonization, therefore improving the possible rates of root canal treatment success. Physical vapor deposition, sol-gel dip coating, electrodeposition, chemical deposition technique and direct current magnetron reactive sputtering have been evaluated among several coating techniques. These coatings have therapeutic value depending on homogeneity, adhesive strength, and biocompatibility. Excellent coating performance is thought to depend critically on the eradication of the natural titanium oxide layer from Ni-Ti alloys. Conclusion: Despite these positive advancements, numerous challenges still exist, including regulatory approval, coating durability, and the need for long-term clinical validation. Self-healing coatings, bioactive layers for regenerative endodontics, and intelligent coatings with antimicrobial release driven by environmental changes should be the main focus of further studies. Bringing these discoveries into practical application depends on cooperation among materials scientists, nanotechnologists, and endodontists, thereby improving the performance and durability of Ni-Ti endodontic files.

Deep carious lesions often lead to pulp exposure, highlighting the need for effective pulp preservation strategies. While root canal treatment was the conv

Aim To compare the prevalence of apical periodontitis (AP), endodontic treatments, quality of endodontic treatments and their association with apical radiolucencies, and decayed, missing and filled teeth (DMFT) scores in patients attending a British NHS hospital in 2008–2009 (Cohort 1/C1) and 2018–2019 (Cohort 2/C2). Methodology Randomly selected panoramic radiographs of 980 patients, evenly distributed into two cohorts: C1 (2008–2009) and C2 (2018–2019) were retrospectively analysed. Patient demographics, number of teeth, presence and quality of endodontic treatments, apical radiolucencies in treated and untreated teeth, endodontic treatment quality, AP prevalence by tooth type, and DMFT scores were compared. Results C1 had significantly higher DMFT scores ( p p p = 0.015), less apical disease (51%, versus 44%; p = 0.04) and fewer endodontically treated teeth (5.5% versus 4.2%; p = 0.007). The percentage of endodontically treated teeth with AP was similar (29.3% versus 27.9%). C2 patients had less unsatisfactorily obturated teeth (63.7% versus 57.6%) though this was not statically significant ( p = 0.072). Conclusion A reduction of caries and endodontic disease burden and a slight improvement in the quality of endodontic treatments in the 2018/2019 cohort was observed. This was not accompanied by increased tooth retention suggesting that more extractions of salvageable teeth were undertaken in the latter cohort

Background/Objectives: This study aimed to assess and compare the elimination of the smear layer and microhardness of dentin in root canals after sequential versus continuous chelation using different agitation techniques. Methods: Sixty-four palatal roots of upper first molars were instrumented to size X3 (Protaper Next files). According to the irrigant solution, samples were assigned to two groups (N = 32/group), 3% NaOCl irrigation followed by 17% EDTA (sequential chelation (SC)), or dual-rinse (3% NaOCl/9% HEDP) irrigation (continuous chelation (CC)). Each group has been divided into four subgroups (n = 8/subgroup), based on agitation techniques used: conventional needle (CN) (control group), EndoActivator (EA), ultrasonic agitation (UAI), and Er.Cr.YSGG 2780 nm (laser). SEM images assessed the smear layer, and Vicker microhardness (VHN) was performed at 50 and 100 µm depths. Data were analyzed using: Kruskal–Wallis, Wilcoxon, and the Mann–Whitney U test. Statistical significance was set at p < 0.05. Results: In the UAI and laser agitation, CC significantly reduced the smear layer presence compared to SC in the apical and coronal thirds, respectively (p < 0.05), and no significant differences were observed in the CN and EA groups between SC and CC (p > 0.05). There were significantly higher VHNs of dentine in CC groups than in SC groups in all sections and depths, except in the apical of the CN group at 50 µm and the coronal section of EA and UAI groups at 100 µm. Conclusions: CC was comparable to SC in smear layer removal. CC had a less detrimental effect on dentin compared with SC.

Aim: Accurate detection of periapical radiolucent lesions (PARLs) is crucial for endodontic diagnosis. While cone beam computed tomography (CBCT) is considered the radiographic gold standard for detecting PARLs in non‐root filled teeth, its use is often limited by cost and radiation exposure. Artificial Intelligence (AI)‐based radiographic analysis has shown the potential to enhance the diagnostic capability of periapical (PA) radiographs, but its accuracy, compared with CBCT, needs further evaluation. The aim of this paper is to assess the diagnostic accuracy of Diagnocat, a commercial AI‐driven platform in detecting PARLs on PA radiographs of teeth diagnosed with irreversible pulpitis or pulp necrosis and scheduled for primary root canal treatment, using CBCT as the reference standard, and to compare Diagnocat's performance with that of experienced clinicians. Methodology: This retrospective diagnostic accuracy study analysed 339 teeth (796 roots). PA radiographs were independently assessed by two experienced, calibrated endodontists and by Diagnocat. CBCT scans, serving as the reference standard, were evaluated by two different endodontists, blinded to the PA radiograph results. Sensitivity, specificity, accuracy and area under the receiver‐operating characteristic curve (AUC‐ROC) were calculated for Diagnocat and clinicians at both tooth and root levels. Results: CBCT identified PARLs in 121 (35.7%) teeth and 240 (30.2%) roots. Diagnocat displayed a high level of correlation with clinicians in determining lesion status, with an agreement of 89%. Clinicians demonstrated significantly higher accuracy at the tooth level (86.1% vs. 78.5%, p < .001) and greater sensitivity (65.3% vs. 47.9%, p < .001) than Diagnocat, while specificity was comparable (97.7% vs. 95.4%, p = .3). Similar trends were observed at the root level. AUC‐ROC values were higher for clinicians than Diagnocat at both tooth (0.81 vs. 0.72) and root (0.77 vs. 0.68) levels, although these differences were not statistically significant. Conclusion: While Diagnocat exhibited high agreement with clinicians in detecting PARLs on PA radiographs, clinicians demonstrated superior accuracy and sensitivity overall. Notably, Diagnocat performed comparably to experienced clinicians in cases without PARLs, highlighting its potential utility for reliably ruling out disease. However, further refinement is required before it can reliably complement clinical judgment in endodontic practice.