Does a Vascularized Fibula Free Bone Grafted Immediately After Hemimandibulectomy in a Child Grow or Relapse During Adolescence?

For young growing children before the end of skeletal maturity, the growth activity of the grafted bone after hemimandibulectomy is not well-known. After an adolescence, such a patient may have facial deformity because the anterior growth point of the mandible is in the condylar neck. A 13-year-old boy was performed hemimandibulectomy with immediate mandibular reconstruction by fibula free flap (FFF) because of a huge ameloblastic fibroma. The authors evaluated the length of FFF on the images of computed tomography (CT) at 5 and 60 months after the operation and compared them by calculating growth rates. Five years after surgery, his facial appearance was symmetry and mandibular function was satisfaction. Although the mandibular bone in the contralateral side grew during 5-year follow-up, the vascularized FFF grafted in the child patient did not significantly grow. Moreover, spontaneous regeneration (SR) and the gradual osteosclerosis were confirmed on the left distal edge of the FFF on the CT imaging. The arrival of SR at the left distal edge of the FFF was considered a part of the reason to compensate the unchanging growth rate of the grafted FFF and contribute for the postoperative good functional and esthetic results.

Impact of Coxsackievirus A6 emergence on hand, foot, and mouth disease epidemic in Osaka City, Japan.

Hand, foot, and mouth disease (HFMD) is an acute febrile illness characterized by fever; sore throat; and vesicular eruptions on the hands, feet, and oral mucosa. Until 2010, HFMD was predominantly associated with enterovirus (EV) A71 and coxsackievirus (CV) A16 in Japan. In 2011, CV-A6 emerged as a primary causative agent, causing the largest HFMD epidemic in Japan since 1981. Since then, CV-A6 has caused large HFMD epidemics every 2 years. The phylogenetic analysis of complete Viral Protein 1 (VP1) sequences revealed that most CV-A6 strains detected from 2011 to 2015 in Osaka City were classified into a different clade compared with CV-A6 strains detected from 1999 until 2009. The majority of CV-A6 strains detected in 2011 and most CV-A6 strains detected from 2013 to 2015 were mainly divided into two distinct genetic groups. Each epidemic strain carried unique amino acid substitutions in the presumed DE, EF, and GH loops of the VP1 protein that is exposed on the surface of the virion. There is a possibility that the appearance of substitutions on the surface of the virion and an accumulation of a susceptible population are significant factors in recent HFMD epidemics.

Retrospective analysis of odontogenic myxoma and odontogenic myxofibroma in the oral and maxillofacial region: a fibrous tissue-related differentiation.

The clinical differences between odontogenic myxoma (OM) and odontogenic myxofibroma (OMF), and the clinical significance of their classifications, remain unclear. This study reviewed the clinicopathological characteristics of patients with OM or OMF and evaluated the fibrous component of the specimens. Medical records of 21 patients with OM or OMF who underwent tumour resection were reviewed. The percentage of fibrous tissue on the representative sections was evaluated using haematoxylin and eosin- and Masson's trichrome-stained specimens. Histopathological diagnoses included 11 OMs and 10 OMFs with no tumour recurrence except for two cases in which the dredging method was applied. More cortical bone perforation was observed in OM than in OMF cases, without significant differences. Location-locularity and apparent diffusion coefficient value (ADC)-cortical bone perforation were significantly correlated in all OM and OMF cases. The percentage of fibrous tissue in specimens showed bimodal distribution bordered by 45%. There was a significant association between diagnosis based on 45% fibrous tissue criterion and the final pathological diagnosis. Our study showed a tendency for cortical bone perforation in OM compared to OMF and correlation between ADC and cortical bone perforation. According to the histopathological analyses, the fibrous component of each case was bimodal with 45%, which may be a criterion to distinguish between OM and OMF. Accumulating knowledge, such as significant differences in prognosis, may allow for minimal surgical treatment options based on the diagnosis according to this novel histopathological criterion.

Clinicopathological analysis of 134 patients with squamous cell carcinoma of the mandibular gingiva.

Objective: The accurate assessment of the involvement of mandibular gingival squamous cell carcinoma (SCC) is essential for determining the extent of resection and is also useful for predicting lymph node metastasis and prognosis. The purpose of this study was to investigate the factors for predicting the prognosis. Study design: We reviewed 134 patients with mandibular gingival SCC treated between 2008 and 2017. The clinical findings, TN stage, relationship between radiographical type and histological pattern, and factors affecting the survival rate were investigated. Results: The moth-eaten radiographic type was significantly associated with histologically infiltrative pattern. For all 134 cases, the 5-year OS was 89.5 %, and 5-year DSS was 93.9 %. The 5-year DSS was 95.0 % for cN0 and/or pN0 cases and 90.3 % for pN (+) cases, with a significant difference. The significant risk factors for lymph node metastasis were teeth extractions by previous physicians and moth-eaten radiographic type. Conclusion: The risk factor for poor prognosis was lymph node metastasis. In addition, teeth extractions by previous physicians and moth-eaten radiographic type were the risk factors for lymph node metastasis. It is recommended that these cases be treated considering the possibility of cervical lymph node metastasis.

Retrograde Migration of an Au-198 Grain to the Submandibular Gland Post Brachytherapy Treatment of Floor of Mouth Cancer.

At our institution, radiation oncologists routinely treat early-stage oral cancer with low-dose-rate brachytherapy (LDR-BRT) using Au-198 grains. In this report, we show a unique case of a patient with a gold grain located within the submandibular gland, found incidentally during follow-up after LDR-BRT for floor of mouth cancer. One month after the implant, he showed sialadenitis-like symptoms, but the pain resolved two months later. All the grains were detected around the anterior sublingual area by computed tomography (CT) four months after the implant. Unexpectedly, 11 months after the implant, CT revealed that a grain was located in an intraglandular site of the submandibular gland. This finding clearly demonstrates that the grain entered Wharton's duct and retrogradely migrated to the submandibular gland through the duct. As a mechanism of the calculus formation within Wharton's duct, retrograde migration of foreign bodies to the inside of the duct has been proposed. Our incidental finding after LDR-BRT highlights the need for monitoring post-LDR-BRT using Au-198 grains for the treatment of floor of mouth cancer and sheds additional light on retrograde theory within Wharton's duct.

Differences in the stemness characteristics and molecular markers of distinct human oral tissue neural crest-derived multilineage cells.

OBJECTIVES: Although multilineage cells derived from oral tissues, especially the dental pulp, apical papilla, periodontal ligament, and oral mucosa, have neural crest-derived stem cell (NCSC)-like properties, the differences in the characteristics of these progenitor cell compartments remain unknown. The current study aimed to elucidate these differences. MATERIAL AND METHODS: Sphere-forming apical papilla-derived cells (APDCs), periodontal ligament-derived cells (PDLDCs), and oral mucosa stroma-derived cells (OMSDCs) from the same individuals were isolated from impacted developing teeth. All sphere-forming cells were characterized through biological analyses of stem cells. RESULTS: All sphere-forming cells expressed neural crest-related markers. The expression of certain tissue-specific markers such as CD24 and CD56 (NCAM1) differed among tissue-derived cells. Surprisingly, the expression of only CD24 and CD56 could be discriminated in human tissues. Although APDCs and PDLDCs exhibited greater mineralized cell differentiation than OMSDCs, they exhibited poorer differentiation into adipocytes in vitro. In immunocompromised mice, APDCs formed hard tissues better than PDLDCs and OMSDCs. CONCLUSIONS: Although cells with NCSC-like properties present the same phenotype, they differ in the expression of certain markers and differentiation abilities. This study is the first to demonstrate the differences in the differentiation ability and molecular markers among multilineage human APDCs, PDLDCs, and OMSDCs obtained from the same patients, and to identify tissue-specific markers that distinguish tissues in the developing stage of the human tooth with immature apex.

An Epidemic of Hand, Foot, and Mouth Disease Caused by Coxsackievirus A6 in Osaka City, Japan, in 2017.

The second largest epidemic of hand, foot, and mouth disease since 1982 occurred in 2017, which involved 6,173 cases in Osaka City, Japan. The main causative agent was coxsackievirus A6 (CV-A6). Phylogenetic analysis revealed that the detected CV-A6 strains belonged to genetic groups A3 and A4 in clade A.

Clinical study on mandibular fracture after marginal resection of the mandible.

OBJECTIVES: Postoperative mandibular fracture (PMF) after marginal resection (MR) of the mandible remains an unresolved issue, and it has been reported that at least 10 mm of postoperative mandibular body height (PMBH) is required to prevent PMF. This study evaluated the clinical, physical, and structural risk factors for PMF in MR patients and determined appropriate preventive measures for PMF. STUDY DESIGN: This retrospective study included 44 patients with lower gingival carcinoma who underwent MR. PMF occurred in four of these patients. Thirteen associated factors identified from medical records and radiographs were statistically analyzed. RESULTS: Mandibular body height (MBH) preservation ratio originally evaluated as less than 0.3, more than 20 remaining teeth after surgery, and inferior alveolar canal (IAC) exposure were significant risk factors for PMF. Prostheses and number of remaining teeth were also correlated with PMF. CONCLUSIONS: The preserved mandibular bone should be reinforced in patients with an MBH preservation ratio of less than 0.3, more than 20 remaining teeth after surgery, and intraoperative IAC exposure. Patients with prostheses are at an increased risk of PMF compared with those without because of stable occlusion and a strong occlusal force. Our novel findings provide useful reference standards for PMF prevention in MR patients.