INTRODUCTION: This study aims to evaluate the biocompatibility of a new light-curable hydrogel-based root canal obturation material, OdneFill, through in vivo and in vitro analyses. METHODS: Intentional overinstrumentation and overobturation were performed on the mandibular first molars of 10-week-old male rats, divided into 4 groups: group 1 (instrumentation only), group 2 (OdneFill), group 3 (gutta-percha + AH Plus), and group 4 (sound teeth). Mandibles were dissected after 3, 28, and 90 days for micro-computed tomography, histological analysis, and immunohistochemical staining and analyzed by two-way analysis of variance and post hoc Tukey test. Cytotoxicity and proinflammatory cytokine expression were assessed using RAW 264.7 cells and analyzed by 1-way analysis of variance and Tukey test (α = 0.05). RESULTS: Micro-computed tomographic analysis showed no significant difference in bone resorption (P > .05). However, AH Plus exhibited a higher inflammatory score (score: 1%-90%, score: 2%-10%) with increased neutrophil and macrophage infiltration in immunostaining (P < .05) compared to the instrumentation only group at day 90. In contrast, Odnefill showed comparable results (score: 0%-50%, score: 1%-30%, score: 2%-20%) to the instrumentation-only group (P > .05). Moreover, Odnefill did not affect the viability of RAW 264.7 cells, whereas the AH Plus extract decreased cell viability and upregulated inflammatory cytokines such as interleukin-1 beta and interleukin-6. CONCLUSIONS: OdneFill demonstrated superior biocompatibility, and a minimal inflammatory response compared to AH Plus.

With increasing life expectancy and an aging population, the demand for dental treatments that preserve natural teeth has grown significantly. Among these treatments, endodontic therapies for pulpitis and apical periodontitis play a vital role, not only in keeping occlusal function, but also in preventing the exacerbation of systemic diseases. Both pulpitis and apical periodontitis are primarily caused by infections of the oral pathobiont within the root canal, leading to inflammation and destruction of the pulp, apical periodontal tissue, and bone. Standard root canal therapy aims to remove the infection source and facilitate natural tissue healing through the body's regenerative capacity. However, challenges remain, including limited tooth functionality after complete pulp removal in pulpitis and insufficient recovery of the large bone defect in apical periodontitis. To address these limitations, endodontic regenerative therapies have emerged as promising alternatives. Pulp regeneration therapy seeks to restore the functionality of dental pulp, while bone regeneration therapy aims to repair and regenerate large bone defects affected by apical periodontal tissue.

BACKGROUND: There is increasing evidence that diagnostic salivary tests measuring inflammatory biomarkers are being developed to assess inflammatory status for early detection, prevention, and progression of periodontal disease. Therefore, the aim of the present study was to investigate and identify the salivary biomarker that can predict the inflammatory status of periodontal disease. METHODS: A total of 36 patients (28 women and 8 men) with an average age of 57 years were investigated. Unstimulated saliva was collected from the recruited subjects and analyzed using SillHa, a saliva-testing device that measures bacteria count, saliva buffer capacity, acidity, leukocyte esterase, protein, and ammonia. Periodontal parameters were then obtained by clinical examination and initial periodontal therapy was performed. Data obtained with SillHa were compared with clinical periodontal parameters at baseline, re-examination (three months from baseline), and final examination (six months from re-examination). RESULTS: Leukocyte esterase activity in saliva measured by SillHa; BOP and PCR measured by clinical examination showed a significant difference between baseline and final examination and between re-examination and final examination. Patients in the lower median group (group 1) had a significant difference in leukocyte esterase activity between baseline and final examination and re-examination and final examination. In addition, patients in Group 1 had significantly lower BOP between baseline and final examination. While patients in the higher median group (group 2) showed a modest decrease in leukocyte esterase activity, which was significant only between baseline and final examination, no significant changes were observed concerning BOP. Furthermore, the associated systemic disease was observed in 30% and 81.2% of group 1 and 2 patients, respectively. CONCLUSION: The results suggest that leukocyte esterase activity in saliva measured by SillHa could serve as a reliable diagnostic marker for monitoring inflammatory status in periodontal disease.

Bone tissue engineering has been developed using a combination of mesenchymal stem cells (MSCs) and calcium phosphate-based scaffolds. However, these complexes cannot regenerate large jawbone defects. To overcome this limitation of MSCs and ceramic scaffolds, a novel bone regeneration technology must be developed using cells possessing high bone forming ability and a scaffold that provides space for vertical bone augmentation. To approach this problem in our study, we developed alveolar bone-derived immature osteoblast-like cells (HAOBs), which have the bone regenerative capacity to correct a large bone defect when used as a grafting material in combination with polylactic acid fibers that organize the 3D structure and increase the strength of the scaffold material (3DPL). HAOB-3DPL constructs could not regenerate bone via xenogeneic transplantation in a micromini pig alveolar bone defect model. However, the autogenic transplantation of mouse calvaria-derived immature osteoblast-like cells (MCOBs) isolated using the identical protocol for HAOBs and mixed with 3DPL scaffolds successfully regenerated the bone in a large jawbone defect mouse model, compared to the 3DPL scaffold alone. Nanoindentation analysis indicated that the regenerated bone had a similar micromechanical strength to native bone. In addition, this MCOB-3DPL regenerated bone possesses osseointegration ability wherein a direct structural connection is established with the titanium implant surface. Hence, a complex formed between a 3DPL scaffold and immature osteoblast-like cells such as MCOBs represents a novel bone tissue engineering approach that enables the formation of vertical bone with the micromechanical properties required to treat large bone defects.