Study of the mandibular canal and its surrounding canals by multi-view cone-beam computed tomography.

OBJECTIVES: To determine the mandibular anatomical structures by observing cone-beam computed tomography (CBCT) from multiple angles. MATERIALS AND METHODS: This retrospective study analyzed 1593 consecutive CBCT images. Ultimately, 95 CBCTs met the inclusion criteria. The mandibular, inferior lingual, and bony canals at the tooth apex were studied by multi-angle observation CBCT. Descriptive statistics were used for statistical analysis. RESULTS: It is beneficial to further observe the anastomosis of the mandibular, lingual, and mandibular canals when the course of the mandibular lingual canal is observed on CBCT cross-section. The frequency of the inferior lingual canal anastomosis with the mandibular canal was 43.2% (95% confidence interval (CI) 33, 53.3) in the sample. The mental foramen was located below the long axis of the tooth in a few samples, with an occurrence rate of 29.5% (95% CI 20.1, 38.8). The occurrence rate of various types of the bony canal at the apex of the tooth in canines, first premolars, second premolars, first molars, and second molars under the root apex was recorded through the multi-angle observation of the dental volume reformat (DVR) and three-dimensional (3D) levels in CBCT. CONCLUSION: This study demonstrates the utility of CBCT imaging in examining mandibular anatomy from multiple angles, providing valuable insights into anatomical variations, and enhancing our understanding of mandibular structures. This research emphasizes the crucial role of meticulous CBCT examination in precisely identifying and understanding key anatomical structures, ultimately reducing the risk of surgical complications. CRITICAL RELEVANCE STATEMENT: By examining cone-beam computed tomography scans from various perspectives, it is possible to determine the precise position of anatomical structures within the jaw. This allows for a more accurate assessment, reducing the risk of harm to these structures during treatment. KEY POINTS: • It is crucial to utilize image data effectively to enhance the comprehension of human anatomy. • We captured detailed images of the mandible from different angles and orientations utilizing cone-beam computed tomography (CBCT). • This study provides essential anatomical information for procedural planning to ensure optimal outcomes and patient safety.

Evaluation of the distribution characteristics of the mandibular lingual foramen and its potential risks during implant surgery using cone-beam computed tomography a cross-sectional, retrospective study.

OBJECTIVES: The lingual foramen is a risk factor for implantation and other mandibular surgeries, but there are few systematic studies on the anatomical and distribution characteristics of the lingual foramen in the entire mandible. MATERIALS AND METHODS: A retrospective study was performed using 405 CBCT images. The anatomical characteristics and symmetrical distribution of the mandibular lingual foramen were analyzed. RESULTS: All patients had at least one lingual foramina. According to the positional relationship between the mandibular lingual foramen and the root apex of tooth, the mandibular lingual foramen is divided into the upper lingual foramen and the lower lingual foramen. Upper lingual foramen were divided into three types according to its running direction, namely Type 1 (Enters the mandible and descend in the direction of the lower edge of the mandible), Type 2 (Enters the mandible and descends in the direction of the lower edge of the mandible with branches), and Type 3 (It enters the mandible and divides into two branches, one ascends toward the crest of the alveolar ridge, and the other descends toward the lower edge of the mandible). And their respective prevalence are 84.0% [95% Tolerance Limit (TL) 81.2%-86.8%], 9.9% [95% TL 7.6%-12.1%], and 6.1% [95% TL 4.3%-8.0%]. In addition, the 81.8% [95% TL 79.0%-84.7%] of the upper lingual foramen is distributed in the central incisor area. Lower lingual foramen were divided into three categories according to the running direction, namely Category 1 (Enters the mandible and ascends toward the buccal bone plate), Category 2 (Enters the mandible and descends toward the buccal bone plate), and Category 3 (Go straight into the mandible toward the buccal bone plate). And their respective prevalence are 29.6% [95% TL 26.4%-32.7%], 50.9% [95% TL 47.5%-54.4%] and 19.5% [95% TL 16.8%-22.3%]. The frequency of lower lingual foramen distributed anteriorly to the mental foramen is 55.8% [95% TL 52.3%-59.2%], mid-mental foramen is 21.4%[95% TL 18.5%-24.2%], and posterior to the mental foramen is 22.8% [95% TL 20.0%-25.8%]. CONCLUSION: Both the upper and lower lingual foramina should be evaluated in the anterior, middle, and posterior regions of the mental foramen before implant surgeries.

[Effect and mechanism of testosterone level on inflammatory bone resorption in periodontitis with mice].

PURPOSE: To investigate the effect of testosterone level on inflammatory bone resorption in periodontitis with mice. METHODS: Forty-eight SD mice were randomly divided into unligated group, sham operation group, castration group, castration + testosterone group, 12 mice in each group. At 6 weeks after ligation, serum testosterone levels were measured, and alveolar bone loss (ABL) and alveolar bone absorption area were compared by hematoxylin - eosin staining and methylene blue staining. The expression of inflammatory cytokine messenger RNA(mRNA) in gingival tissue was measured by real-time fluorescence quantitative PCR. SPSS 20.0 software package was used to analyze the data. RESULTS: Serum testosterone level among four groups was the highest in the unligated group, followed by castration + testosterone group, sham operation group and castration group, with significant difference(P<0.05). The ABL of the castration + testosterone group was significantly larger than that of the unligated group, the sham operation group and the castration group(P<0.05). The ABL of the castration group was significantly smaller than that of the sham operation group (P<0.05). The alveolar bone resorption area of the castration + testosterone group was significantly larger than that of the unligated group, the sham operation group and the castration group(P<0.05). The alveolar bone resorption area of the castration group was significantly smaller than that of the sham operation group (P<0.05). Interleukin-1ß (IL-1ß) mRNA, interleukin-6(IL-6) mRNA and tumor necrosis factor-α(TNF-α) mRNA levels in gingival tissues of sham operation group, castration group and castration + testosterone group were significantly higher than the unligated group. The levels of interleukin-10(IL-10) mRNA in gingival tissues of sham operation group, castration group and castration + testosterone group were significantly lower than those in unligated group(P<0.05). The level of IL-1ß mRNA in gingival tissues among four groups was the the highest in the unligated group, followed by castration + testosterone group, sham operation group and castration group, with significant difference (P<0.05). Serum testosterone levels were positively correlated with ABL, alveolar bone resorption area, and IL-1ß (P<0.05). CONCLUSIONS: Periodontitis with mice have decreased testosterone levels, and long-term testosterone depletion can reduce inflammatory bone resorption in alveolar bone, which may be achieved by reducing the level of IL-1ß, indicating that reduction of the level of testosterone in periodontitis patients may be a new treatment target for alveolar bone resorption.

LncRNA LEF1-AS1 promotes osteogenic differentiation of dental pulp stem cells via sponging miR-24-3p.

The role of lncRNA LEF1-AS1 in the regulation of osteogenic differentiation of dental pulp stem cells (DPSCs) is still obscure. Here, we demonstrated that LncRNA LEF1-AS1 expression was associated with osteogenic differentiation of DPSCs and overexpression of LEF1-AS1 promoted osteogenic differentiation. Moreover, lncRNA LEF1-AS1 and miR-24-3p could directly regulate each other and LEF1-AS1 acted as sponge partner of miR-24-3p. Furthermore, LEF1-AS1 and miR-24-3p synergized to regulate osteogenic differentiation of DPSCs. Finally, we verified TGFBR1 was the direct target of miR-24-3p in osteogenic differentiation of DPSCs and miR-24-3p/LEF1-AS1 sponged to regulate TGFBR1 expression. Our study revealed a novel mechanism about how did lncRNA LEF1-AS1 execute function in osteogenesis of DPSCs and thus might serve as potential therapeutic target for the bone regeneration in the dental pulp.

miR-31-5p Is a Potential Circulating Biomarker and Therapeutic Target for Oral Cancer.

MicroRNAs have been proposed as novel biomarkers for the diagnosis and treatment of many types of cancer. The levels of five candidate microRNAs (miRNAs) (miR-99a-5p, miR-31-5p, miR-138-5p, miR-21-5p, and miR-375-3p) in sera from oral cancer patients and paired tumor and normal tissues were detected by real-time qPCR. The diagnostic power of these miRNAs was analyzed by receiver operating characteristic (ROC) curves. Patient-derived xenograft (PDX) models of oral cancer were established and utilized to verify the potential therapeutic effect of miR-31-5p. Candidate miRNAs were screened from our previous studies and verified in 11 paired oral cancer and adjacent normal tissues. Only serum miR-31-5p levels were significantly different between oral cancer patients and healthy controls and between pre- and postoperative patients. Based on the logistic regression model, this panel of five miRNAs distinguished oral cancer patients from healthy control, with an area under the ROC curve (AUC) of 0.776 (sensitivity = 76.8% and specificity = 73.6%). Furthermore, a miR-31-5p mimic enhanced the proliferation of normal epithelial cells, and antagomiR-31-5p inhibited the proliferation of oral cancer cells in vitro. In vivo, antagomiR-31-5p significantly inhibited tumor growth in oral cancer PDX models. Our findings suggest that circulating miR-31-5p might act as an independent biomarker for oral cancer diagnosis and could serve as a therapeutic target for oral cancer.

The serum biomarker chemerin promotes tumorigenesis and metastasis in oral squamous cell carcinoma.

Chemerin, which is encoded by retinoic acid receptor responder 2 (RARRES2), has been found to be related to malignant tumours, but its role in the development of oral squamous cell carcinoma (OSCC) is largely unexplored. In the present study, a higher serum level of chemerin was evident in patients with OSCC than in healthy individuals, and this high level of chemerin significantly decreased after tumour resection. In addition, high chemerin levels were positively associated with advanced tumour stage and lymph node metastasis. The expression levels of chemerin and Chemerin Receptor 23 (ChemR23) were positively correlated with the migration and invasion of OSCC cell lines. Recombinant chemerin (R-chemerin) enhanced the in vitro migration, invasion and proliferation of OSCC cells in a concentration-dependent manner, and short hairpin RNAs (shRNAs) targeting RARRES2 decreased chemerin expression and inhibited OSCC cell metastasis and proliferation both in vitro and in vivo Additionally, R-chemerin activated manganese superoxide dismutase (SOD2) and increased the amount of intracellular hydrogen peroxide (H2O2), leading to a significant decrease in E-cadherin expression and dramatic increase in the expression of phosphorylated ERK1/2 (p-ERK1/2), Slug, Vimentin and N-cadherin, but shRNAs targeting RARRES2 reversed these effects. Moreover, knockdown of ChemR23 with small interfering RNAs (siRNA) significantly inhibited chemerin-induced OSCC cell migration/invasion and SOD2 activity. Our results revealed that chemerin is a novel biomarker for OSCC. Chemerin/ChemR23 promotes tumorigenesis and metastasis in OSCC and may be a new therapeutic target for OSCC.