Comparison of Easydo Activator, ultrasonic and needle irrigation techniques on sealer penetration and smear layer removal in vitro.

The effects of Easydo Activator (EA), a new sonic irrigation system, on sealer penetration at the root apex were compared to needle irrigation (NI) and passive ultrasonic irrigation (PUI) in this study. Forty-two single-rooted teeth were prepared and randomly divided into three groups (n = 14): group 1: NI; group 2: PUI; and group 3: EA. A solution of 3% sodium hypochlorite (NaOCl) was used for irrigation. Nine teeth in each group were filled with AH Plus sealer mixed with CY5 fluorescent dye and a single gutta-percha cone. The sealer penetration area, maximum penetration depth and percentage of sealer penetration at 5 mm and 1 mm from the apex were analyzed by confocal laser scanning microscopy (CLSM). The remaining 5 teeth in each group were subjected to test smear layer scores by scanning electron microscopy (SEM). The CLSM evaluation showed that increases in the area, depth and percentage of sealer penetration were detected at 1 and 5 mm from the root apex in the PUI group compared with the NI group, and greater increases were observed in the EA group (P < 0.05). The SEM experiment showed that the lowest scores for the smear layer and debris removal were achieved by the EA group when compared with the PUI and NI groups (P < 0.05). In conclusion, EA was superior to PUI and NI regarding sealer penetration at the root apex during endodontic treatment, and it could provide a new technical idea for clinical root canal therapy.

Comparison of EASYDO ACTIVATOR, passive ultrasonic, and needle irrigation techniques on the treatment of apical periodontitis: a study in rats.

OBJECTIVES: To evaluate the long-term therapeutic effect of EASYDO ACTIVATOR, passive ultrasonic irrigation, and needle irrigation in experimental apical periodontitis in rats. MATERIALS AND METHODS: Sprague-Dawley male rats were used to produce periapical lesions. The pulp chambers of the bilaterally first mandibular molars were exposed and left open for 21 days. The rats were divided into four groups according to different irrigation protocols. Seven days after irrigation, the mandibles were removed for micro-CT, histological, and immunohistochemical analysis. Serum levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were assessed by enzyme-linked immunosorbent assays (ELISA). Statistical data were analyzed by one-way analysis of variance (ANOVA) with LSD tests. RESULTS: The passive ultrasonic irrigation and EASYDO ACTIVATOR groups had the smallest apical lesions compared to the other groups (P < 0.05), while the needle irrigation group had smaller lesions than the control group (P < 0.05). The EASYDO ACTIVATOR group had less inflammation infiltration compared to the control and needle irrigation groups (P < 0.05). The control and needle irrigation groups had more TNF-α expression compared to the passive ultrasonic irrigation and EASYDO ACTIVATOR groups (P < 0.05). The lowest IL-6 expression was observed in the EASYDO ACTIVATOR group. The EASYDO ACTIVATOR group had the lowest serum level of TNF-α than other groups (P < 0.05). IL-6 expression was significantly lower in the EASYDO ACTIVATOR group in comparison with the control and needle irrigation groups (P < 0.05). CONCLUSIONS: EASYDO ACTIVATOR can significantly reduce the apical lesions and decrease the inflammatory response around the periapical area. CLINICAL RELEVANCE: EASYDO ACTIVATOR is recommended for clinical application.

Role of NOD2 and hepcidin in inflammatory periapical periodontitis.

The immunological response occurring during periapical inflammation includes expression of nucleotide binding oligomerization domain containing 2 and hepcidin. Nucleotide binding oligomerization domain containing 2 deficiency increases infiltration of inflammatory cells close to alveolar bone. Hepcidin has an important role in iron metabolism affecting bone metabolism.We investigated the role of nucleotide binding oligomerization domain containing 2 and hepcidin in inflammatory periapical periodontitis. Periapical periodontitis was induced in rats and confirmed by micro-computed tomography. Nucleotide binding oligomerization domain 2 and hepcidin were evaluated through immunohistochemistry. Bioinformatics analysis was undertaken usingthe Kyoto Encyclopedia of Genes and Genomes and Gene Ontology databases. Micro-computer tomography revealed alveolar bone resorption in the periapical region and furcation area of mandibular molars in rats of the periapical periodontitis group. Immunohistochemistry showed increased expressionof nucleotide binding oligomerization domain containing 2 and hepcidin around root apices in rats of the periapical periodontitis group. Bioinformatics analysis of differentially expressed genes in inflamed and non-inflamed tissues revealed enrichment in the NOD-like receptor signaling pathway. Our data suggest that nucleotide binding oligomization domain contain2 and hepcidin have important roles in periapical periodontitis severity because they can reduce alveolar bone loss.They could elicit new perspectives for development of novel strategies for periapical periodontitis treatment.

Comparison of sealer penetration of sonic activation versus conventional needle irrigation: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Most existing studies comparing the efficiency of sonic irrigation (SI) and conventional needle irrigation (CNI) in increasing the penetration of sealers into dentine tubules are controversial; and this study aimed to determine whether the use of SI can lead to greater sealing ability than CNI, during the root canal treatment. METHODS: The EMBASE, PubMed, and Cochrane Library databases were used to find confocal laser scanning microscopy studies evaluating percentage and maximum depth of sealer penetration following the use of SI or CNI in mature permanent teeth until October 2022. The critical estimative checklist of randomized controlled trials of the standardized Joanna Briggs Institute was adopted to independently score the quality of each study. The random-effect model for meta-analysis was used to analyse for each canal segment (apical, middle, coronal). The results are shown in the forest plots as weighted mean differences (WMDs) with 95% confidence intervals (95% CIs). RESULTS: Ninety-seven articles were included in the preliminary screening, and nine of them were included in this study. Eight studies were included in the meta-analysis.The meta-analysis exhibited great increases in the coronal (WMD: 8.09, 95% CI 2.78-13.40/WMD: 165.32, 95% CI 128.85-201.80), and middle segments (WMD: 8.81, 95% CI 5.76-11.87/WMD: 132.98, 95% CI 68.71-197.25) for the percentage and maximum depth of sealer penetration, respectively. The percentage of sealer penetration in the apical thirds region was nonsignificant (WMD: 4.73, 95% CI - 2.34-11.80). However, the maximum depth of sealer penetration in the apical thirds region was significant (WMD: 121.46, 95% CI 86.55-156.38). Chi-squared analysis revealed heterogeneity scores of 0.0-70.0% and 44.0-90.0% for the percentage and maximum depth of sealer penetration, respectively. DISCUSSION: This review verified that SI significantly improves tubular dentin sealer penetration in most areas of the root canal; thus, SI may lead to better filling efficiency and anti-reinfection effects than CNI during and after the root canal therapy. Nevertheless, a large heterogeneity in the current data comparing the irrigation efficiency of SI versus CNI in the apical third of the root canal was found, implying the necessity to standardize root canal irrigation procedures and obtain more accurate results in this area. TRIAL REGISTRATION: INPLASY database (INPLASY202270116).

miR-124-3p increases in high glucose induced osteocyte-derived exosomes and regulates galectin-3 expression: A possible mechanism in bone remodeling alteration in diabetic periodontitis.

The mechanisms underlying the two-way relationship between diabetes mellitus (DM) and periodontitis are unclear. We examined a possible effect of galectin-3 (Gal-3), a factor in DM and bone metabolism, on periodontitis with or without DM. Using enzyme-linked immunosorbent assay, we detected saliva Gal-3 in patients with periodontitis, with or without type 2 diabetes mellitus (T2DM). In animal models, we measured periodontal bone microarchitecture via micro computed tomography, and detected Gal-3, Runt-related transcription factor 2 (Runx2), and interleukin-6 (IL-6) expression in alveolar bone. Applying dual luciferase reporter assay, we explored the target binding of miR-124-3p and Gal-3. We examined osteocyte-derived exosomes with transmission electron microscopy and detected miR-124-3p, Gal-3, and IL-6 expression in exosomes. Saliva Gal-3 was increased in DM compared with controls but decreased in patients with moderate periodontitis and DM compared with those who had moderate periodontitis only. Alveolar bone mass was increased in DM and exacerbated in DM with periodontitis. Gal-3 and Runx2 were both increased in periodontitis and DM compared with controls, but decreased in DM with periodontitis compared with DM alone. MiR-124-3p targeted and inhibited Gal-3 expression in vitro. Osteocytes secreted exosomes carrying miR-124-3p, Gal-3, and IL-6, which were influenced by high glucose. These findings indicate that osteocyte-derived exosomes carrying miR-124-3p may regulate Gal-3 expression of osteoblasts, especially under high-glucose conditions, suggesting a possible mechanism for DM-related alveolar bone pathologies.

Endoplasmic reticulum stress remodels alveolar bone formation after tooth extraction.

Bone healing in tooth extraction sockets occurs in a complex environment containing saliva and many microorganisms and is affected by many factors. Endoplasmic reticulum (ER) stress affects bone metabolism, but the role of ER stress in bone healing after tooth extraction remains unclear. We utilized a rat tooth extraction model, in which we promoted wound healing by using salubrinal to regulate the ER stress response. Western blot analysis showed increased expression of p-eIF2α/eIF2α, Runx2 and alkaline phosphatase (ALP) in bone tissue, and histological assays showed irregularly arranged and new bone with more collagen fibres 14 days after tooth extraction and after modulating the degree of ER stress. Micro-CT showed that modulating ER stress to an appropriate degree increases bone filling in regards to the density in the bottom and the surrounding bone wall of the tooth extraction wounds. Transmission electron microscopy showed rough ER expansion and newly formed collagen fibrils in osteoblasts after modulating ER stress to an appropriate degree. We also used different concentrations of salubrinal to evaluate the resistance to tunicamycin-induced ER stress in an osteogenic induction environment. Salubrinal restored the tunicamycin-induced decrease in the viability of primary calvarial osteoblasts and increased the expression of Runx2 and ALP, and decreased p-eIF2α/eIF2α in a dose-dependent manner. Taken together, the results demonstrate that ER stress occurred after tooth extraction, and regulating the degree of ER stress can promote bone healing in tooth extraction sockets, providing clinical evidence for bone healing.

Oral cavity-derived stem cells and preclinical models of jaw-bone defects for bone tissue engineering.

BACKGROUND: Jaw-bone defects caused by various diseases lead to aesthetic and functional complications, which can seriously affect the life quality of patients. Current treatments cannot fully meet the needs of reconstruction of jaw-bone defects. Thus, the research and application of bone tissue engineering are a "hot topic." As seed cells for engineering of jaw-bone tissue, oral cavity-derived stem cells have been explored and used widely. Models of jaw-bone defect are excellent tools for the study of bone defect repair in vivo. Different types of bone defect repair require different stem cells and bone defect models. This review aimed to better understand the research status of oral and maxillofacial bone regeneration. MAIN TEXT: Data were gathered from PubMed searches and references from relevant studies using the search phrases "bone" AND ("PDLSC" OR "DPSC" OR "SCAP" OR "GMSC" OR "SHED" OR "DFSC" OR "ABMSC" OR "TGPC"); ("jaw" OR "alveolar") AND "bone defect." We screened studies that focus on "bone formation of oral cavity-derived stem cells" and "jaw bone defect models," and reviewed the advantages and disadvantages of oral cavity-derived stem cells and preclinical model of jaw-bone defect models. CONCLUSION: The type of cell and animal model should be selected according to the specific research purpose and disease type. This review can provide a foundation for the selection of oral cavity-derived stem cells and defect models in tissue engineering of the jaw bone.

Kangfuxin Accelerates Extraction Socket Healing by Promoting Angiogenesis Via Upregulation of CCL2 in Stem Cells.

Kangfuxin (KFX) shows potential in wound healing, but its role in socket healing is unclear. This research finds increased bone mass, mineralization, and collagen deposition in KFX-treated mice. Mouse bone marrow mesenchymal stem cells, human periodontal ligament stem cells (hPDLSCs), and human dental pulp stem cells (hDPSCs) are treated with KFX under osteogenic induction. RNA-sequencing reveals upregulated chemokine-related genes, with a threefold increase in chemokine (C-C motif) ligand 2 (Ccl2). The conditioned medium (CM) of hPDLSCs and hDPSCs treated with KFX promotes endothelial cell migration and angiogenesis. Ccl2 knockdown abolishes CM-induced endothelial cell migration and angiogenesis, which can be reversed by recombinant CCL2 treatment. KFX-treated mice showed increased vasculature. In conclusion, KFX increases the expression of CCL2 in stem cells, promoting bone formation and mineralization in the extraction socket by inducing endothelial cell angiogenesis. © 2023 American Society for Bone and Mineral Research (ASBMR).

Spheroid co-culture of BMSCs with osteocytes yields ring-shaped bone-like tissue that enhances alveolar bone regeneration.

Oral and maxillofacial bone defects severely impair appearance and function, and bioactive materials are urgently needed for bone regeneration. Here, we spheroid co-cultured green fluorescent protein (GFP)-labeled bone marrow stromal cells (BMSCs) and osteocyte-like MLO-Y4 cells in different ratios (3:1, 2:1, 1:1, 1:2, 1:3) or as monoculture. Bone-like tissue was formed in the 3:1, 2:1, and 1:1 co-cultures and MLO-Y4 monoculture. We found a continuous dense calcium phosphate structure and spherical calcium phosphate similar to mouse femur with the 3:1, 2:1, and 1:1 co-cultures, along with GFP-positive osteocyte-like cells encircled by an osteoid-like matrix similar to cortical bone. Flake-like calcium phosphate, which is more mature than spherical calcium phosphate, was found with the 3:1 and 2:1 co-cultures. Phosphorus and calcium signals were highest with 3:1 co-culture, and this bone-like tissue was ring-shaped. In a murine tooth extraction model, implantation of the ring-shaped bone-like tissue yielded more bone mass, osteoid and mineralized bone, and collagen versus no implantation. This tissue fabricated by spheroid co-culturing BMSCs with osteocytes yields an internal structure and mineral composition similar to mouse femur and could promote bone formation and maturation, accelerating regeneration. These findings open the way to new strategies in bone tissue engineering.

Sex Variations in the Oral Microbiomes of Youths with Severe Periodontitis.

OBJECTIVE: Periodontitis is an inflammatory disease of microbial etiology caused primarily by dysbiosis of the oral microbiota. Our aim was to compare variations in the composition of the oral microbiomes of youths with severe periodontitis according to gender. METHODS: Subgingival plaque samples collected from 17 patients with severe periodontitis (11 males and 6 females) were split for 16S rRNA gene sequencing. The composition, α-diversity, and ß-diversity of the patients' oral microbiomes were compared between the males and the females. Linear discriminant analysis effect size (LEfSe) was used to analyze the specific taxa enriched in the two groups. Functional profiles (KEGG pathways) were obtained using PICRUSt based on 16S rRNA gene sequencing data. RESULTS: The Chao1 index and phylogenetic diversity whole tree were significantly higher in males than in females. The Simpson and Shannon indices were not significantly different between the two groups. ß-Diversity suggested that the samples were reasonably divided into groups. The Kruskal-Wallis test based on the relative abundance of species, combined with the LEfSe analysis showed that the dominant bacteria in males were Pseudomonas and Papillibacter, whereas the dominant bacteria in women were Fusobacteriales and Tannerella. KEGG analysis predicted that the variation in the oral microbiome may be related to the immune system in women, whereas immune system diseases were the dominant pathway in men. CONCLUSION: We found sex-specific differences in the oral microbiome in a sample of youths with severe periodontitis. The differences may be related to changes in immune homeostasis and lead to a better understanding of periodontitis.

Gender Variations in the Oral Microbiomes of Elderly Patients with Initial Periodontitis.

Periodontitis is a globally prevalent disease that imposes a functional and aesthetic burden on patients. The oral microbiome influences human health. The aim of this study was at assessing gender variation in the subgingival bacterial microbiome of elderly patients with initial periodontitis and to determine the causes of this variation. Twelve males and twenty females (range 50-68 years old) with initial periodontitis provided subgingival plaque samples. 16S rRNA gene sequencing, QIIME-based data processing, and statistical analyses were carried out using several different analytical approaches to detect differences in the oral microbiome between the two groups. Males had higher Chao1 index, observed species, and phylogenetic diversity whole tree values than females. Analysis of ß-diversity indicated that the samples were reasonably divided by the gender. The linear discriminant analysis effect size showed that the most representative biomarkers were the genus Haemophilus in males, whereas the dominant bacteria in females were Campylobacter. Kyoto Encyclopedia of Genes and Genomes analysis showed that predicting changes in the female oral microbiota may be related to the immune system and immune system diseases are the main factor in males. These data suggest that gender may be a differentiating factor in the microbial composition of subgingival plaques in elderly patients with initial periodontitis. These results could deepen our understanding of the role of gender in the oral microbiota present during initial periodontitis.