A retrospective study of the malignant change of odontogenic keratocyst.

The odontogenic keratocyst (OKC) is a common cystic lesion of the maxilla and mandible. Squamous cell carcinoma (SCC) arising from OKC or dysplasia occurring in OKC is rare. This study aimed to explore the incidence and clinical features of the dysplasia and malignant transformation of OKC. In this study, 544 patients diagnosed with OKC were collected. Among them, 3 patients were diagnosed as SCC arising from OKC, and 12 patients were diagnosed as OKC with dysplasia. The incidence was calculated. Clinical features were analyzed by chi-square test. In addition, a representative case reconstructing mandible with vascularized fibula flap under general anesthesia was reported. And cases reported before were reviewed. The incidence of the dysplasia and malignant transformation of OKC, which are highly associated with the clinical features of swelling and chronic inflammation, is about 2.76%. But the relevance between the dysplasia and malignant transformation and age, gender together with pain is not statistically high. All in all, the clinical features of swelling and chronic inflammation can be considered as characteristics of the dysplasia and malignant transformation of OKC. Although the pain isn't statistically relevant, it may be a dangerous clew. Also, combined with earlier literatures, the dysplasia and malignant transformation of OKC shows unique features of radiographs and histopathology.

Myofascial iliac crest flap for reconstruction of combined oral mucosa-mandibular defects: A single-centre experience.

BACKGROUND: Deep circumflex iliac artery (DCIA) myofascial iliac crest flap has been used for combined oral mucosa-mandibular defects reconstruction. The bone component of this composite flap can reconstruct the mandible with superior contour match, and the muscle fascia which used for repairing the oral mucosa defect will transform into an oral mucosa-like appearance. To explore its scope of clinical application and how the fascia transformed into oral mucosa will give surgeons flexibility to reconstruct the combined oral mucosa-mandibular defects. METHODS: A retrospective review of 18 patients who received combined oral mucosa-mandibular defects reconstruction with DCIA myofascial iliac crest flaps from Dec 2016 to Dec 2020 was performed. The characteristics of the mandibular defects and the flaps were recorded. The postoperative dynamic changes of one graft's fascia were observed from serial photographs. RESULTS: All myofascial iliac crest flaps survived successfully. The bone grafts were from 4.0 to 9.5 cm (mean 7.6 ± 1.5 cm) in length and from 2.0 to 3.5 cm (mean 2.7 ± 0.4 cm) in height. The sizes of fascia were from 13.5 to 48.0 cm2 (mean 27.2 ± 9.4 cm2). The grafted fascia firstly changed into a yellow pseudomembrane-like appearance, and then experienced muscle oedema before finally transformed into an oral mucosa-like appearance at about 60 days after operation. CONCLUSION: Myofascial iliac crest flap is a good option for reconstruction of combined oral mucosa-mandibular defects because of its excellent bone and oral mucosa matches.

An investigation on the biotribocorrosion behaviour of CoCrMo alloy grafted with polyelectrolyte brush.

Surface grafting of polyelectrolyte brush, such as 3-sulfopropyl methacrylate potassium salt (SPMK), on hip implant materials has been reported to reduce the wear of the orthopaedic bearing surface. However, the biotribocorrosion behaviour of the SPMK brush has not been taken into consideration in previous research. In the present study, SPMK was grafted on Co28Cr6Mo alloy through photo-induced polymerization, and the biotribocorrosion behaviour was investigated by a series of frictional-electrochemical tests using a universal materials tester combined with an electrochemical measurement (three-electrode) system. Co28Cr6Mo disk and polyethylene (PE) pin were used as the contact pair, and the lubricants were 0.9% saline solution (NaCl) and 0.9% saline solution coupled with 25% bovine serum albumin (BSA). The results showed that SPMK was successfully grafted on Co28Cr6Mo alloy, which was confirmed by the comparison of Raman spectroscopy and static contact angle of the samples before and after surface modification. The greatly reduced electrochemical parameters such as corrosion current and pitting potential indicated that the corrosion rate of Co28Cr6Mo alloy was significantly reduced following SPMK grafting. Additionally, the frictional-electrochemical coupled measurement performed under reciprocating sliding demonstrated that the lowest corrosion current was obtained for the SPMK-grafted Co28Cr6Mo disk, with 0.9% NaCl coupled with 25% BSA as the electrolyte. It is indicated from the present study that SPMK polyelectrolyte brush can greatly improve the anti-biotribocorrosion properties of Co28Cr6Mo alloy, and thus has potential application on surface modification of hip implant materials.