Journal of endodontics最新文献

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.

Introduction: Medication-related osteonecrosis of the jaws (MRONJ) is a condition that causes progressive bone destruction and compromises patients' function, aesthetics, and quality of life.

Objectives: This study aims to investigate the role of untreated apical periodontitis (AP) in the development of MRONJ.

Methods: A comprehensive search was performed in PubMed/MEDLINE, Web of Science, Scopus, and Embase. Gray literature was assessed using the ProQuest database. The eligibility criteria consisted of (1) preclinical studies; (2) use of antiresorptive, antiangiogenics, or other drugs known to cause MRONJ; (3) studies evaluating the development of osteonecrosis in regions of AP lesions. The following studies were excluded: (1) non-animal studies. Two independent reviewers performed data extraction and the assessment of the risk of bias.

Results: From an initial dataset of 239 records, we included 11 studies. Induction of periapical lesions was performed most often after the administration of bisphosphonates. Zoledronic acid was the most used drug. Histologic or clinical evidence of MRONJ in areas of untreated AP was reported in 72.72% of the studies. Furthermore, areas with AP presented MRONJ more frequently, with or without clinical signs.

Conclusions: This systematic review of preclinical studies indicates that untreated AP, in the context of antiresorptive therapy, may increase the risk of MRONJ. Our findings provide mechanistic insights that clarify how AP may contribute to MRONJ pathogenesis, offering a theoretical background to support clinical observations. While human studies suggest a potential pathogenic interaction, they remain limited by heterogeneous designs, variable definitions of oral infections, and frequent grouping of AP with other conditions. These limitations underscore the translational significance of our preclinical analysis. Overall, our results reinforce the importance of early diagnosis and management of endodontic infections in patients receiving antiresorptive particularly cancer patients exposed to higher cumulative doses and highlight the need for well-designed prospective clinical studies to determine whether AP constitutes an independent risk factor for MRONJ.

Introduction: Although ultrasonic inserts are frequently used for the instrumentation of flat root canals, there is a lack of studies investigating whether instrument contact with the canal walls induces the formation of dentinal microcracks. This study aimed to evaluate the formation of apical microcracks, caused by ultrasonic instrumentation, using micro-computed tomography (microCT) and optical coherence tomography (OCT).

Method: Twenty maxillary second premolars were randomly divided into 2 groups (n = 10): ultrasonic group and brushing group. All specimens were initially prepared using Reciproc Blue files 25/.05 and 40/.06. The brushing group received additional brushing movements with Reciproc Blue 40/.06 and the ultrasonic group underwent instrumentation with a Clearsonic Black ultrasonic insert. Pre- and post-instrumentation images were obtained using both microCT and OCT and were analyzed with specialized software.

Results: Statistically significant difference was observed for the treatment variable regarding apical microcrack presence (P < .05). In the brushing group, all apical microcracks identified post-instrumentation were also present preoperatively. In contrast, new incidences were identified in the ultrasonic group via microCT. No significant differences were found for the evaluator (P > .05) or the imaging technique used (P > .05). Intra- and interexaminer agreement was nearly perfect, with kappa values ranging from 0.858 to 0.975.

Conclusion: The inclusion of an ultrasonic insert during biomechanical preparation did not significantly increase the incidence of apical microcracks when compared with a nonultrasonic protocol. OCT demonstrated high reliability for detecting apical microcracks in extracted teeth.

This case report describes the replacement of a missing maxillary right central incisor (tooth number 8) with a supernumerary tooth using cone beam computed tomography based digital planning, a three-dimensional printed donor replica tooth, osseodensification, and connective tissue grafting. A 36-year-old male presented with general periodontitis and a healed socket in the number 8 region 3 months postavulsion. Based on cone beam computed tomography scans, auto-transplantation of a single-rooted mandibular supernumerary tooth into a surgically created socket in the number 8 region was planned. Root canal treatment was performed on the donor tooth prior to its extraction. Digital planning was performed, and a three-dimensional replica of the donor tooth was designed and printed. The surgically created socket was prepared with an osseodensification technique. Extraction of the donor tooth was performed atraumatically, and soft tissue grafting and splint stabilization was performed after its placement in the socket. A definitive crown was placed at 12 months. At 30 months the transplanted tooth was functional and asymptomatic, with no clinical or radiographic signs of apical pathosis.