Urs D.A. Müller-Richter

Freehand SPECT-guided sentinel lymph node biopsy in early oral squamous cell carcinoma.

In oral squamous cell carcinoma (OSCC), cervical lymph node status is the most important prognostic factor. Compared to elective neck dissection, reduced morbidity and better quality of life was demonstrated for sentinel lymph node biopsy, which is controversial because of the reduced detection rate of sentinel lymph nodes in close proximity to the injection site (also known as the shine‐through phenomenon).

Historical development of alloplastic temporomandibular joint replacement before 1945

Resections of the temporomandibular joint (TMJ) have been carried out for about 150 years. This article reviews the beginning of TMJ surgery technique before 1945 by carrying out extensive inquiries in public and private libraries and collections. Before 1945 the technique of alloplastic reconstruction of the TMJ was mainly influenced by German and French surgeons. Reconstruction was limited to replacement of the condyle. The role of the TMJ within the orofacial system was not considered. Interposition of alloplastic implants, resection dressings and prostheses were the dominant technique. The main concerns were sterilisation, biocompatibility and implant fixation. No evidence-based data on outcomes are available from that time. By 1945 reconstruction of the TMJ involved the close cooperation of surgeons and dentists.

Gene expression of nestin, collagen type I and type III in human dental follicle cells after cultivation in serum-free medium

BackgroundUndifferentiated human dental cells and especially human dental follicle cells are interesting for potential dental treatments. These somatic stem cells are cultured usually in cell culture medium containing bovine serum. In the age of bovine spongiform encephalopathy (BSE), a serum-free cell culture system for dental follicle cells are recommended, if these cells will be applied in dentistry.PurposeHowever, less is known about the cultivation of dental follicle cells in serum-replacement medium. In this study, we cultivated dental follicle cells in serum-free cell culture medium, which is normally applied for neuronal stem/progenitor cells.Materials and methodsDental follicle cells were cultivated in both serum-free and serum-containing cell culture media, and gene expression profiles were recorded for connective tissue markers collagen type I and type III and for the human dental follicle cell marker nestin.ResultsIt is interesting to note that the gene expressions of collagens and nestin were similar after applying both cell culture conditions.ConclusionAlthough the gene expression of dental follicle cell markers was unchanged, a more appropriate serum-free cell culture medium is recommended for cell proliferation of dental follicle cells.

MAGE-A antigens in lesions of the oral mucosa

Oral squamous cell carcinoma develops continuously out of predamaged oral mucosa. For the physician and pathologist, difficulties arise in distinguishing precancerous from cancerous lesions. MAGE-A antigens are tumor antigens that are found solely in malignant transformed cells. These antigens might be useful in distinguishing precancerous from cancerous lesions. The aim of this study was to verify this assumption by comparing MAGE-A expression in benign, precancerous, and cancerous lesions of the oral mucosa. Retrospectively, biopsies of different oral lesions were randomly selected. The lesions that were included are 64 benign oral lesions (25 traumatic lesions (oral ulcers), 13 dental follicles, and 26 epulis), 26 oral lichen planus, 123 epithelial precursor lesions (32 epithelial hyperplasia found in leukoplakias, 24 epithelial dysplasia found in leukoplakias, 26 erythroplasia with oral epithelial dysplasia, and 41 carcinomas in situ in erythroleukoplakias). The lesions were immunohistochemically stained with the poly-MAGE-A antibody 57B, and the results were compared. Biopsies of oral lichen planus, oral ulcers, dental follicles, epulis, and leukoplakia without dysplasia showed no positive staining for MAGE-A antigens. Leukoplakia with dysplasia, dysplasia, and carcinomata in situ displayed positive staining in 33%, 65%, and 56% of the cases, respectively. MAGE-A antigens were not detectable via immunohistochemistry in benign lesions of the oral mucosa. The staining rate of dysplastic precancerous lesions or malignant lesions ranged from 33% to 65%. The MAGE-A antigens might facilitate better differentiation between precancerous and cancerous lesions of the oral mucosa.

Influence of epidermal growth factor receptor expression on the cetuximab and panitumumab response rates of head and neck carcinoma cells

OBJECTIVES To examine the impact of epidermal growth factor receptor (EGFR) expression level on the efficacy of monoclonal antibodies against the EGFR. METHODS In four human head and neck carcinoma cell lines, epidermal growth factor expression was knocked down by lentiviral RNA interference. Next, the efficacies of cetuximab and panitumumab at concentrations of 4, 40, and 400 μg/ml were measured by real time cell analysis for a 48-h duration. Finally, the different response rates to the drugs were statistically analyzed. RESULTS The lentiviral EGFR knockdown efficiency ranged from 18 to 54 % across all of the cell lines. All original cell lines exhibited rather poor or inverse responses with regard to EGFR-AB treatment. In contrast, inhibiting EGFR expression in the same cell lines yielded statistically significant better responses to cetuximab or panitumumab treatment. CONCLUSIONS The cell lines used in this study responded poorly to cetuximab and panitumumab. Better anti-EGFR treatment efficacy was related to lower EGFR expression in head and neck cancer cell lines. These findings might influence the selection of patients to receive cetuximab and panitumumab treatment for head and neck cancer.

Treatment of Intracapsular Condylar Fractures With Resorbable Pins

J Oral Maxillofac Surg 2011. The surgical treatment of intracapsular condylar fractures (ICFs) of the mandible is complex. Type A and B fractures (classified by Neff et al and others), in particular, are difficult to treat. These fracture types are characterized by laterocranial to mediocaudal fracture lines with ventromedial dislocation of the fragments. The Axhausen and Bockenheimer retroauricular approaches or the Rasse and preauricular approach are usually performed. The complications associated with these surgical approaches include facial nerve injury, impaired circulation in the ear, bleeding, and scarring. In the past, several surgical and conservative treatment options have been used. Titanium minilate osteosynthesis with lag screws has been perormed, and resorbable osteosynthesis materials ave also been used. Postoperative complicaions have included malposition of the fragment, racture redislocation, or malocclusion. The indiations for the surgical treatment of ICFs have long een debated because of the lack of evidence-based esults. Because of these risks, secondary operations should be avoided. Plate or screw removal in titanium osteosynthesis necessitates surgery; therefore, resorbable osteosynthesis materials are preferable. In a previous in vitro study, the retention forces achieved with ultrasound-activated resorbable pins were compared with those of titanium screws. A retention force of 900 N was obtained for titanium screws compared with 300 N for ultra-

Hemimandibulectomy after bisphosphonate treatment for complex regional pain syndrome: a case report and review on the prevention and treatment of bisphosphonate-related osteonecrosis of the jaw.

BACKGROUND The increase in reported cases of osteonecrosis of the jaw has increased the clinical significance of bisphosphonate therapeutic agents in the dentistry field. METHODS We present a rare and severe case of bisphosphonate-related osteonecrosis of the jaw caused by medicamentous treatment of complex regional pain syndrome. This article reviews the current international prevention and treatment guidelines with regard to bisphosphonate treatment. RESULTS Even rare indications for bisphosphonate treatment may lead to devastating effects on the patient. CONCLUSIONS Dentists and physicians who prescribe bisphosphonates should be familiar with the side effects of these drugs and the management of these side effects. To prevent negative outcomes, it is important that there be a close collaboration among the doctors involved and that a thorough medical history is obtained; this is especially true because the range of indications for bisphosphonate treatment increases every year.

Mucormycosis of the head and neck.

INTRODUCTION Mucormycosis of the head and neck is a rare disease increasingly occurring in immunocompromised patients. We report on two cases with different outcomes. CASE REPORTS A 63-year-old female presented with a recently developed deformation of her right cheek and nose combined with a loosening of the teeth. Further examination revealed mucormycosis of the maxilla. Hemimaxillectomy and secondary bony reconstruction with oral rehabilitation were performed. The second patient was a 54-year-old male who suffered from multiple myeloma. After receiving an allogeneic haematopoietic stem cell transplant, he developed a necrotizing infection of the right midface. Histopathological investigation confirmed the diagnosis of mucormycosis. The patient died one day after radical surgical resection. DISCUSSION These two cases demonstrate the variability of mucormycosis. Although slow progression of the disease is possible, a high level of attentiveness and expedient treatment are necessary due to the high risk of a devastating course.

The human HECA interacts with cyclins and CDKs to antagonize Wnt-mediated proliferation and chemoresistance of head and neck cancer cells.

There is a growing evidence that the human homologue of the Drosophila headcase (HECA) plays an important role in human carcinogenesis. So far specific protein interaction partners and affected signaling pathways of HECA are still elusive. In a recent study we showed that HECA overexpression in oral squamous-cell carcinoma (OSCC) keratinocytes has tumor suppressive effects resulting in a recuperation of cell cycle control concerning the entry and progression of S-phase, G2- and M-phase. Currently, quantitative RT-PCR and immunohistochemical analysis of primary tumor tissue from OSCC patients demonstrate that HECA expression is markedly decreased compared to normal control patients with abundant HECA expression. Additionally, there is nearly no HECA expression in OSCC metastases. Here, we show that HECA expression is negatively controlled by the Wnt-pathway and TCF4, a Wnt related transcription factor, binds to the HECA promoter. Furthermore, immunocytochemistry reveals colocalization of HECA with the cyclin dependent kinase CDK9. Immunoprecipitation experiments and proximity ligation assays further reveal an interaction of HECA with CDK2, CDK9, Cyclin A and Cyclin K, a direct transcriptional target of the p53 tumor suppressor. Silencing HECA in OSCC cell lines leads to a significant increase of cell division and a markedly increased resistance against the chemotherapeutic cisplatin. On the contrary, HECA overexpressing OSCC cell lines show decreased resistance of OSCC cells against cisplatin. Therefore, HECA could be considered as future therapeutic agent against Wnt-dependent tumor progression.

Performance of cone beam computed tomography in comparison to conventional imaging techniques for the detection of bone invasion in oral cancer.

Detecting bone invasion in oral cancer is crucial for therapy planning and the prognosis. The present study evaluated cone beam computed tomography (CBCT) for detecting bone invasion in comparison to standard imaging techniques. A total of 197 patients with diagnoses of oral cancer underwent CBCT as part of preoperative staging between January 2007 and April 2013. The sensitivity, specificity, and accuracy of CBCT were compared with panoramic radiography (PR), multi-slice computed tomography (CT) or magnetic resonance imaging (MRI), and bone scintigraphy (BS) using McNemars test. Histopathology and clinical follow-up served as references for the presence of bone invasion. CBCT and BS (84.8% and 89.3%, respectively), as well as CBCT and CT/MRI (83.2%), showed comparable accuracy (P = 0.188 and P = 0.771). CBCT was significantly superior to PR, which was reconstructed based on a CBCT dataset (74.1%, P = 0.002). In detecting bone invasion, CBCT was significantly more accurate than PR and was comparable to BS and CT/MRI. However, each method has certain advantages, and the best combination of imaging methods must be evaluated in prospective clinic trials.