Aim: Although uncommon, medical emergencies arise in general dental practice. Inadequate data on their severity and frequency makes targeting medical education for general dental practitioners difficult. This also makes planning for unexpected events challenging for practitioners and makes collaborating with emergency physicians burdensome. We aimed to clarify the incidence and characteristics of a dental outpatient department’s medical emergencies.Methods: This single‐center, retrospective, observational study was undertaken with patients who visited the dental outpatient department of Okayama University Hospital during the 8‐year period. The primary outcome of the study was to identify the incidence and characteristics of medical emergencies in the dental outpatient department. Then we examined the timing of medical emergencies, administered medications, and final disposition (home/admission).Results: During the period, 1,146,929 patients were enrolled. Forty‐two patients (0.0037%) were consulted as medical emergencies. More than 60% of the incidents were vasovagal syncope, and dehydration and hypoglycemia were the second most prevalent at 9.5%. The most common types of dental treatments were tooth extraction (45.2%), followed by general dental treatment (28.6%), and other dental surgery such as implant placement (14.3%). Types of medical emergencies occurred equally before, during, and after dental treatment. Antihypertensive agents, sedatives, or glucose were used. For patients with emergencies, 90.5% recovered during the day and returned home, and 9.5% were hospitalized.Conclusion: The incidence of medical emergencies was low in our dental outpatient department. Knowledge of basic management principles, regular education for emergency care, and practicing first aid skills are mandatory for safe patient management.

Determining an appropriate sample size in human cadaveric studies remains a long‐standing and unresolved challenge. Unlike other basic science fields, anatomical research is constrained by factors such as limited human donor availability, cultural considerations, and ethical restrictions. Despite these limitations, researchers are often asked to justify sample sizes, yet no standardized guidelines currently exist. To quantitatively assess sample sizes in recent human cadaveric studies and propose evidence‐based recommendations for future research, a PubMed search was conducted on February 26, 2024, using the term human cadaveric study . The articles published in 2023 and 2024 were screened, yielding 770 eligible studies. Data extracted included the total sample size, number of classified groups, and journal impact factor (IF). Descriptive statistics, linear regression, and correlation analyses were performed. Continuous variables were summarized using medians and interquartile ranges (IQR). The median sample size was 11.5 (IQR: 7–20), and 47.9% of studies used 10 or fewer specimens. The median number of classified groups was 3 (IQR: 2–4). Linear regression showed that studies dividing specimens into 2–6 groups often failed to meet the recommended sample size per group based on regression modeling. No significant correlation was found between sample size and journal IF ( r = −0.062, p = 0.115). Most cadaveric studies rely on small sample sizes due to inherent constraints, yet many still attempt a subgroup analysis without sufficient statistical power. Although flexibility is essential in anatomical research, we recommend a minimum total sample size of 10 for basic studies and at least five samples per group for those involving classification. Cadaveric sample size alone does not predict journal impact, highlighting the importance of methodological rigor over quantity.

Sonic hedgehog (SHH) and its signaling have been identified in several human cancers, and increased levels of its expression appear to correlate with disease progression and metastasis. However, the role of SHH in bone destruction associated with oral squamous cell carcinomas is still unclear. In this study we analyzed SHH expression and the role played by SHH signaling in gingival carcinoma-induced jawbone destruction. From an analysis of surgically resected lower gingival squamous cell carcinoma mandible samples, we found that SHH was highly expressed in tumor cells that had invaded the bone matrix. On the other hand, the hedgehog receptor Patched and the signaling molecule Gli-2 were highly expressed in the osteoclasts and the progenitor cells. SHH stimulated osteoclast formation and pit formation in the presence of the receptor activator for nuclear factor-κB ligand (RANKL) in CD11b⁺ mouse bone marrow cells. SHH upregulated phosphorylation of ERK1/2 and p38 MAPK, NFATc1, tartrate-resistant acid phosphatase (TRAP), and Cathepsin K expression in RAW264.7 cells. Our results suggest that tumor-derived SHH stimulated the osteoclast formation and bone resorption in the tumor jawbone microenvironment.

BackgroundCisplatin (CDDP) plays a central role in chemotherapy for head and neck squamous cell carcinoma (HNSCC), but drug resistance in HNSCC chemotherapy remains a problem, and the mechanism of CDDP resistance is unclear. We investigated CDDP-resistance mechanisms mediated by extracellular vesicles (EVs) and ATPase copper transporting beta (ATP7B) in HNSCC.MethodsWe established CDDP-resistant sublines of HNSCC cells and verified their ATP7B expression. We used an EV secretion inhibitor (GW4869) and ATP7B short hairpin (sh)RNA transfection to examine the correlation between EV secretion and ATP7B expression.ResultsThe CDDP-resistant HNSCC sublines showed decreased CDDP sensitivity and increased ATP7B expression. GW4869 suppressed ATP7B expression, and ATP7B shRNA transfection suppressed EV secretion. The suppressions of EV secretion and ATP7B expression both enhanced CDDP's cell-killing effect.ConclusionsEVs were involved in the ATP7B-mediated mechanism underlying CDDP resistance. Further clarification of the EV-induced CDDP-resistance mechanism may lead to novel therapeutic strategies for HNSCC.

Methotrexate-associated lymphoproliferative disorder (MTX-LPD) is an iatrogenic immunodeficiency-associated lymphoproliferative disorder that occurs mainly with MTX use. This disorder has been associated with Epstein-Barr virus (EBV) infection. In 2017, the WHO newly defined the disease concept of EBV-positive mucocutaneous ulcer (EBV-MCU) as a good-prognosis EBV-related disease. Here, we report 10 cases of MTX-LPD or EBV-MCU in the oral mucosa. This retrospective, observational study was conducted with MTX-LPD or EBV-MCU in the oral mucosa patients who visited us during the nine year period from 2012 to 2021. We gathered the basic information, underlying disease, histopathological evaluation, treatment and prognosis for the subjects. All were being treated with MTX for rheumatoid arthritis. EBV infection was positive in all cases by immunohistochemistry. A complete or partial response was obtained in all cases with the withdrawal of MTX. Our results suggests that the most common risk factor for developing EBV-MCU is the use of immunosuppressive drugs. The most common site of onset is the oral mucosa, which may be attributed to the mode of EBV infection and the high incidence of chronic irritation of the oral mucosa. A small number of patients had been diagnosed with MTX-LPD, but we consider that these cases were EBV-MCU based on our study.

Background/Aim: Oral squamous cell carcinoma (OSCC) is the most common malignancy in the head/neck region, and cervical lymph node (CLN) metastasis is a strong poor-prognosis factor. In addition, many patients with OSCC experience recurrence despite multidisciplinary treatment. We sought to identify factors associated with CLN metastasis and recurrence in patients with OSCC. Patients and Methods: We evaluated a total of 45 patients and 233 target CLNs. The longest diameter of the target CLN, the shortest diameter of the target CLN (LS), the area of the target CLN, and the relative computed tomography (CT) values of the target CLNs calculated based on the CT values of the internal jugular vein (LCT) were obtained from preoperative CT images, and the maximum standardized uptake values of the primary tumor (pSUV) and target CLN (nSUV) were obtained from preoperative ¹⁸F-fluorodeoxyglucose-positron emission tomography/CT images. We performed immunohistochemical staining for cytokeratin 13 (CK13) and 17 (CK17) on neck dissection tissues. Results: A discrimination equation was used that can predict CLN metastasis with a 92.2% discrimination rate using LS, LCT, pSUV, and nSUV. The CLNs were divided into discrimination and non-discrimination groups based on discriminant equations and CK13 and CK17 were used as the objective variables. A significantly higher recurrence rate was observed in the non-discrimination group (CK13: 5-year recurrence rate 28.6% vs. 64.3%, p<0.01; CK17: 5-year recurrence rate 28.0% vs. 76.0%, p<0.01). Conclusion: CLN metastases in OSCC can be assessed by combining preoperative imaging. The combined use of CK13 and CK17 expression with imaging findings offers an integrated approach to predict OSCC recurrence.