A comparison of two types of electrospun chitosan membranes and a collagen membrane in vivo.

BACKGROUND: Electrospun chitosan membranes subjected to post-spinning processes using either triethylamine/tert-butyloxycarbonyl (TEA/tBOC) or butyryl-anhydride (BA) modifications to maintain nanofiber structure have exhibited potential for use in guided bone regeneration applications. The aim of this study was to evaluate ability of the modified membranes to support healing of bone-grafted defects as compared to a commercial collagen membrane. METHOD: TEA/tBOC-treated and BA-treated chitosan membranes were characterized for fiber morphology by electron microscopy, residual trifluoroacetic acid by19F NMR and endotoxin level using an endotoxin quantitation kit (ThermoScientific, US). Chitosan membranes were cut into 12 mm diameter disks. An 8 mm calvarial defect was created in each of 48 male rats and then filled with Bio-Oss (Geistlich, US) bone graft. The grafted defects were covered with either (1) TEA/tBOC-treated chitosan membrane (2) BA-treated chitosan membrane or (3) the control BioMend Extend (Zimmer Biomet, US) collagen membrane. After 3 and 8 weeks, the rats were euthanized and calvaria was retrieved for microCT and histological analyses (n = 8/group/time points). RESULTS: Both TEA/tBOC-treated and BA-treated membranes were composed of nanofibers in the ∼231 to ∼284 nm range respectively, exhibited no TFA salt residue and low endotoxin levels (≤0.1 ± 0.01 EU/membrane). All membranes supported increased bone growth from 3 weeks to 8 weeks though there was no significant difference among the membrane types. However, TEA/tBOC treated and BA treated chitosan membranes both showed significantly greater bone density (∼6% greater at 3 weeks and ∼8% greater at 8 weeks) as compared to BioMend Extend collagen membrane at both time points (p = 0.0002). CONCLUSIONS: Chitosan membranes supported better bone healing based on bone density than the collagen membrane.

Adenosquamous Carcinoma of the Tongue.

A 51-year-old white female presented with a painful ulcer of the left ventrolateral tongue. An incisional biopsy confirmed a diagnosis of adenosquamous carcinoma. The adenosquamous carcinoma is an uncommon malignant tumor with histopathological features of a squamous carcinoma and an adenocarcinoma. A definitive diagnosis requires histopathological examination of a deep biopsy involving the submucosal tissue. This malignant tumor shows aggressive behavior with early invasive growth and a poor prognosis. The histopathological findings and differential diagnosis of a case of adenosquamous carcinoma of the tongue are discussed.

Mechanically stable surface-hydrophobilized chitosan nanofibrous barrier membranes for guided bone regeneration.

The use of chitosan based nanofiber membranes in guided bone regeneration (GBR) is limited by its uncontrolled swelling and mechanical instability in aqueous environments. This paper describes the significantly improved stability and properties of surface butyrylated chitosan nanofiber (BCSNF) membranes that greatly enhance their potential in GBR. The BCSNF membranes exhibited an overall degree of substitution of 1.61, an average diameter of 99.3 ± 33.7 nm, and a 75% decrease in swelling with an approximate doubling in suture pull out strengths as compared to unmodified fibers in aqueous environment. In a five week phosphate-buffered saline-lysozyme degradation study, it was found that the remaining mass fraction of BCSNF membranes was 11.5% more than that of unmodified fibers. In vitro, the BCSNF membranes were found to support the adhesion and proliferation of fibroblasts and were cell occulusive. In vivo, the BCSNF membranes were found to significantly improve the regeneration of a rat calvarial critical size defect in a 12 week healing period and showed better barrier function than commercially available collagen membranes with little soft tissue penetration through the membranes. Taken together, these data provide strong scientific evidence for use of BCSNF membranes in GBR applications.

Pseudomyogenic Hemangioendothelioma: A Vascular Tumor Previously Undescribed in the Oral Cavity.

The pseudomyogenic hemangioendothelioma (PMH) is a low-grade malignant vascular neoplasm of different tissue planes including skin and soft tissue. Primary tumors in the skeletal muscle and bone have also been diagnosed. The PMH was introduced into the WHO classification of tumors of soft tissue and bone in 2013. This is the first description of oral involvement. A 21-year-old female presented with a 2-month old swelling of her gingiva. The swelling appeared red in color and was soft in consistency. A clinical diagnosis of a pyogenic granuloma was made and an incisional biopsy was submitted for histopathological evaluation. The lesion consisted of a proliferation of spindle and epithelioid looking cells. Cells were arranged in loose fascicles and sheets. Rhabdomyoblast-like cells were also seen. No mitotic figures were present. Lesional cells were reactive to cytokeratin AE1/AE3 and CD31. Lesional cell reactivity to S100 protein, HMB 45, SMA, Desmin and CD34 was negative. Following the diagnosis, a wide excision for clear margins was performed. No recurrence has been reported 2 years since the removal. The PMH is a cutaneous tumor that behaves in an indolent fashion. This is the first report of oral involvement by this neoplasm. Recognition of its histopathological features and immunohistochemical reactivity will prevent misadventures in the diagnosis of oral lesions.

In vitro and in vivo evaluations of a novel post-electrospinning treatment to improve the fibrous structure of chitosan membranes for guided bone regeneration.

Electrospun chitosan membranes have been investigated for guided bone regeneration but are susceptible to swelling, dissolution, and loss of biomimetic nanofiber structure due to residual acid salts. A novel process was investigated for acidic salt removal from chitosan electrospun in 70% trifluoroacetic acid (TFA) by treating with triethylamine (TEA)/acetone and di-tert-butyl dicarbonate (tBOC) instead of the common Na2CO3 treatment. TFA salt removal and nanofiber structure stabilization were confirmed by EDS, FTIR, 19F NMR and electron microscopy before and after soaking in water. Membrane degradation after 4 weeks in PBS with 100 µg ml-1 lysozyme and osteoblastic proliferation were similar between TEA/tBOC-treated and Na2CO3-treated membranes. A simulated surgical tear test using surgical tacks showed that the peak tensile tear strength of the TEA/tBOC-treated chitosan membranes (62.1 ± 1.9 N mm-1) was significantly greater than a commercial polylactic acid (PLA) membrane (13.4 ± 0.4 N mm-1), similar to one commercial collagen membrane (55.3 ± 7.5 N mm-1) but lower than another commercial collagen membrane (133.9 ± 21.5 N mm-1). Rat 8 mm critical-sized calvarial defects covered with TEA/tBOC-treated chitosan membranes prevented soft tissue infiltration and supported new bone growth (15.76 ± 10.28%) similar to a commercial collagen membrane (16.08 ± 10.69%) at 12 weeks based on microCT analyses. Hence our novel TEA/tBOC process significantly improved nanofiber structure and mechanical strengths of electrospun chitosan membranes as compared to Na2CO3 treated membranes, without affecting in vitro degradation or cytocompatibility, improved membrane mechanical properties to be greater than a commercial PLA membrane and to be in range of commercial collagen membranes and supported calvarial bone defect healing similar to collagen. Thus TEA/tBOC-treated chitosan membranes exhibit many characteristics and properties that strongly support their potential for use in guided bone regeneration.

Mandibular abnormalities in a patient with neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder characterized by the presence of cutaneous neurofibromas, multiple cafd-au-lait spots and pigmented nodules of the iris known as Lisch nodules. In some cases, the diagnosis can be made at birth while in others the diagnosis is made later in life based on the appearance of additional criteria. We describe radiographic abnormalities of the mandible in a young adult male with NF1.

Slow-growing gingival mass.

OBJECTIVES: A 33-year-old woman presented with a slow growing palatal gingival mass. The clinical differential diagnosis included benign tumors and tumor-like lesions, including the pyogenic granuloma, peripheral giant cell granuloma, peripheral ossifying fibroma, giant cell fibroma, peripheral odontogenic tumors, and oral focal mucinosis. STUDY DESIGN: The lesion was excised and histopathological examination followed by immunohistochemical staining was carried out. RESULTS: The microscopic findings and the immunohistochemical reactivity was diagnostic for a nerve sheath myxoma. CONCLUSIONS: The clinical features, microscopic findings, immunohistochemistry, and the differential diagnosis including the relationship to the neurothekeoma are discussed.

The epithelioid blue nevus: A rare intraoral nevomelanocytic tumor.

The epithelioid blue nevus (EBN) is considered a cutaneous marker of the Carney complex. Sporadic EBN has been reported in patients not exhibiting the Carney complex. The EBN does not exhibit unique clinical features that help to differentiate it from other lesions and is often provisionally diagnosed as an acquired melanocytic nevus, or a malignant melanoma. A 52-year-old African-American female had a 3-4 mm bluish macule of the left anterior hard palate. An excisional biopsy was performed to rule out an incipient melanoma. Formalin-fixed, hematoxylin and eosin-stained sections were examined microscopically. On the basis of histopathological features, a diagnosis of EBN was rendered. We document a case of the rare EBN affecting the oral mucosa. The patient did not exhibit any features associated with the Carney complex. Two years post-operatively, there is no evidence of a recurrent tumor.

Cancellous osteoma of the maxillary tuberosity: case report.

The osteoma is a benign, bone-forming lesion that is not considered a true neoplasm. It almost exclusively affects the flat bones of the skull and face. Jaw lesions may cause facial deformity and impair oral function. Multiple osteomas may be associated with Gardner's syndrome. Clinically and radiographically, osteomas may need to be differentiated from other bone-forming lesions. This article describes a cancellous osteoma of the left maxillary molar and tuberosity area and differentiates it from other benign and malignant lesions, including the parosteal osteosarcoma.

Third molar development in the estimation of chronologic age in american blacks as compared with whites.

Third molar (M3) development determined from dental radiographs in American blacks (African Americans; n=637) aged 14-24 years was contrasted against American whites (n=563) from a previous study using the method of Demirjian et al. Differences were assessed using descriptive statistics and the parametric proportional hazards model. For each developmental stage, the probability of an individual being at least 18 years old was evaluated. As in other M3 studies, there were highly significant modal differences, but the age ranges at each stage overlapped considerably. Black-white differences were highly significant with developmental stages occurring in blacks a year or so earlier. Gender differences also varied significantly, both with increasing age and between races. The empirical likelihood that an African American male with fully developed M3's is at least 18 years old is 93% and that for African American female is 84%. Corresponding risks for whites are 90% and 93%.