Contrary melanoma-associated antigen-A expression at the tumor front and center: A comparative analysis of stage I and IV head and neck squamous cell carcinoma.

There is a growing body of evidence indicating that several melanoma-associated antigen-A (MAGE-A) subgroups contribute to the malignancy of head and neck cancer. The present study retrospectively analyzed the expression of all known MAGE-A subgroups in the tumor front and center of 38 head and neck cancer patients (Union for International Cancer Control stage I or IV) by immunohistochemistry. MAGE-A1, -A6, -A8, -A9 and -A11 were expressed at significantly higher levels at the tumor front of stage IV specimens compared with the tumor front of stage I specimens. In stage I cancer, the tumor center and front ratio (C/F ratio) for each subgroup was >1.0. In stage IV cancer, the C/F ratio was <1.0 in 9/11 subgroups. The most significant change in the expression pattern was observed for MAGE-A11. These results indicated that there is a marked alteration and shift to the invasive front of almost all MAGE-A subgroups, but particularly MAGE-A11, during the progression of head and neck squamous cell carcinoma.

Impact of radiotherapy on implant-based prosthetic rehabilitation in patients with head and neck cancer: A prospective observational study on implant survival and quality of life-Preliminary results.

PURPOSE: To study implant-based prosthetic rehabilitation of head and neck cancer patients with focus on implant survival and quality of life. MATERIALS AND METHODS: The prospective observational study presents preliminary results of 29 edentulous head neck cancer patients (20 patients after radiotherapy) with 165 OsseoSpeed implants. Implant success after 1-year follow-up was evaluated by means of the Albrektsson criteria. Quality of life was analysed with the EORTC QLQ-C30, QLQ-H&N35, and OHIP 14 questionnaires. RESULTS: The overall implant survival rate after 1 year was 95.2% (157/165). Implant success measured by the Albrektsson criteria showed a lower success rate of 86.7% (143/165), mainly because of peri-implant marginal bone loss with a mean of 0.8 mm after 1 year. Xerostomia (p = 0.008), implant insertion within the radiation target volume (p = 0.09), implantation in transplanted bone (p = 0.05), and smoking (p = 0.041) were the main reasons for implant failure, followed by D4 bone quality, maxillary implant site, and insufficient primary stability. Speaking, swallowing, eating, as well as social integration and individual self-confidence had considerably improved 1 year after denture placement compared to before treatment. CONCLUSION: Implant-based prosthetic rehabilitation of head and neck cancer patients is possible at a calculable risk and significantly improves patients' quality of life.

Primary and secondary leiomyosarcoma of the oral and perioral region--clinicopathological and immunohistochemical analysis of a rare entity with a review of the literature.

PURPOSE: Leiomyosarcoma (LMS) rarely occurs in the head and neck region. These tumors present with a wide range of clinical features, so the diagnosis is predicated on conventional microscopic findings coupled with immunohistochemical analysis. PATIENTS AND METHODS: Clinical and histologic data of 7 patients with LMS of the head and neck were recorded retrospectively. In addition to routine immunohistochemistry, staining for cell cycle regulator proteins p16 and p21 was performed. RESULTS: Five LMSs (4 intraoral, 1 dermal cheek) occurred primarily in the oral and perioral region. Two LMSs (parietal and sinonasal) were diagnosed as metastases originating from the uterus and pelvis. Treatment of the primary LMSs consisted of radical tumor resection with clear margins. Distant metastases from LMSs were irradiated or excised as palliative treatment. Three of 5 patients (60%) with primarily excised LMS developed recurrence after an average of 7 months, with lung metastases occurring after 17 months. In 1 patient, cervical lymph node metastases were detected after 10 months. Of all patients, 5 died after an average survival period of 2.4 years. The mean survival period of the 5 patients with primary LMS of the head and neck was 3.3 years. All tumors were positive for vimentin and α-smooth muscle actin, with 57% of tumors showing positive nuclear expression of p16 and 71% of p21. Lack of p16 nuclear expression was associated with a shorter mean survival time (1.3 vs 4.3 yr for p16 positivity). CONCLUSION: Lung and cervical lymph node metastases often occur in LMS of the head and neck. Presurgical staging, including gynecologic examination, whole-body computed tomography, and sometimes positron-emission or computed tomography, to rule out LMS metastasis is mandatory. Surgical resection of the tumor should be given top priority. Lack of p16 reactivity may have a prognostic value for LMS because it was related to a trend toward poorer survival.

Transcription factors TP53 and SP1 and the osteogenic differentiation of dental stem cells.

Dental follicle is a loose connective tissue that surrounds the developing tooth. Dental follicle cells (DFCs) have a promising potential for tissue engineering applications including periodontal and bone regeneration. However, little is known about the molecular mechanisms underlying osteogenic differentiation. In a previous study we detected that more than 35% of genes that are regulated during osteogenic differentiation of DFCs have promoter binding sites for the transcription factors TP53 and SP1. However, the role of these transcription factors in dental stem cells is still unknown. We hypothesize that both factors influence the processes of cell proliferation and differentiation in dental stem cells. Therefore, we transiently transfected DFCs and dental pulp stem cells (SHED; Stem cells from human exfoliated decidiuous teeth) with expression vectors for these transcription factors. After overexpression of SP1 and TP53, SP1 influenced cell proliferation and TP53 osteogenic differentiation in both dental cell types. The effects on cell proliferation and differentiation were less pronounced after siRNA mediated silencing of TP53 and SP1. This indicates that the effects we observed after TP53 and SP1 overexpression are indirect and subject of complex regulation. Interestingly, upregulated biological processes in DFCs after TP53-overexpression resemble the downregulated biological processes in SHED after SP1-overexpression. Here, regulated processes are involved in cell motility, wound healing and programmed cell death. In conclusion, our study demonstrates that SP1 and TP53 influence cell proliferation and differentiation and similar biological processes in both SHED and DFCs.

Novel strategies in therapy of head and neck cancer.

In addition to the currently available conventional therapeutic modalities i.e. chemotherapy, radiotherapy and surgery, there is a desperate need for more effective and less toxic therapies for head and neck malignancies. Chemotherapy alone shows high toxicity and a low survival rate. In some cases, malignant cells develop resistance to a particular drug and to combat this, a variety of approaches like intra-arterial therapy, induction chemotherapy, immunotherapy, photodynamic therapy as well as targeted molecular therapy have recently been employed. Techniques like intra-arterial and induction chemotherapy have showed some improvement in survival rate. Immununotherapy is in the experimental stages while photodynamic therapy is being clinically applied, but because of its side effects it is not very popular. Utilizing specific molecular targets with their inhibitors (like inhibitors of EGFR and VEGF); either alone or in combination with conventional therapy, may improve the survival rate of these patients. Blocking the signaling pathway (P13k/Akt/mTOR), with or without chemotherapy, may also overcome the problem of drug resistance. These modalities hold the promise of being more selective - harming fewer normal cells, reducing side effects and improving the quality of life. The various options and novel strategies currently available to the treating physician are critically examined in this review.

Retrospective analysis of orbital floor fractures--complications, outcome, and review of literature.

This retrospective study aimed at investigating indications, surgical approaches, and the materials used for orbital floor reconstructions, as well as the clinical follow-up, particularly with regard to postoperative complications. This study comprised 189 patients who underwent surgery for fractures of the orbital floor between 2003 and 2007. Diagnosis and treatment were based on both physical examination and computed tomography scan of the orbit. Patients were retrospectively analyzed for data, such as mechanism of injury, classification of fracture, and complications. The most common cause of injury was physical assault followed by traffic accidents. Surgery was conducted with a mean delay of 2.9 days after the incident. Mid lower eyelid incision was the most common surgical approach to the orbital floor. For orbital floor reconstruction, polydioxanone sheets (70.5%) were mainly used, followed by Ethisorb Dura (23.3%) and titanium mesh (6.2%). There were 19.0% of patients who showed postoperative complications: 5.8% suffered from persisting motility impairment, 3.7% from enophthalmos, 3.2% from consistent diplopia, 2.6% from ectropion, and 0.5% from orbital infection. Intraorbital hematoma (3.2%) represented the most severe complications, one patient suffered lasting impairment of sight and another one, complete blindness of the affected eye. If postoperative impairment of vision becomes evident, immediate surgical intervention is mandatory. Retrobulbar hematoma is more likely to occur in heavily traumatized patients with comminuted fractures and also in patients taking anticoagulative medication. The subciliary approach to the orbit and repeated operations by the same approach are associated with a higher risk of developing ectropion.

Kimura's disease in a white man.

BACKGROUND: Kimura's disease is a rare inflammatory disease that mainly affects Asians and most often occurs in the deep lymph nodes of the head and neck. We report on a rare case of Kimura's disease in the hard palate of a white man. METHOD: A 56-year-old white man was seen with a rapidly growing mass in the upper jaw. A complete tumor resection with hemimaxillectomy was performed. The tumor, which showed signs of inflammation, was located within the bone and the soft tissue. RESULTS: Kimura's disease was diagnosed by histopathologic examination of the resected tumor. CONCLUSION: This case demonstrates that Kimura's disease, though rare, is not limited to the Asian population. We present a case of a tumor in a white man. This adds another possibility for uncertain differential diagnoses of rapidly growing tumor masses.

Altered expression of cell-cell adhesion molecules ß-catenin/E-cadherin and related Wnt-signaling pathway in sporadic and syndromal keratocystic odontogenic tumors.

Differential diagnosis of the keratocystic odontogenic tumor (KCOT) still represents a challenging problem especially if compared with the dentigerous cyst, which is similar in clinical and radiological course. Histological assessment of this entity may therefore draw crucial attention since various radical procedures are recommended for such lesions in contrast to dentigerous cysts. Since recent reports could prove the involvement of wingless(Wnt)-signaling pathway and ß-catenin in the pathogenesis of many odontogenic and neoplastic lesions indicating impairment of cell-cell adhesion, we investigated the expression of two Wnt-signaling pathways, Wnt-1 and Wnt-10A as well as ß-catenin and E-cadherin along with other related proteins in both lesions. We found a significant down-regulation in the expression of cell adhesion proteins ß-catenin and E-cadherin along with alteration of Wnt-1 and Wnt-10A expression in the epithelium of KCOT. We assessed a specific focal distribution pattern of p63 in the suprabasal cell layer and a significant up-regulation of cyclin D1. Furthermore, laminin α-2 was a characteristic marker labelling only the basement membrane of dentigerous cysts. These results provide a new hypothesis explaining a molecular mechanism to understand initiating and development of KCOTs and an alternative therapeutic approach, especially for syndromal patients, where these multilocal lesions may involve and destroy wide orofacial bony structures.

Survey of congenitally missing teeth in orthodontic patients in Eastern Bavaria.

This retrospective study examined the occurrence of congenitally missing permanent teeth and the need for dental treatment in the Regensburg University Medical Centre of Eastern Bavaria. Using a dental administration software tool, a total of 1442 patients who presented for orthodontic treatment between 1994 and 2006 were identified. After exclusion of 89 patients with incomplete records, 1353 subjects (635 males and 718 females) remained for analysis. Of these, 1130 had no missing permanent teeth, 52 had cleft lips, 110 had one to two teeth missing, 34 had three to five missing teeth, and 27 had greater than or equal to six missing teeth. The analyses focused on the type and number of missing teeth and on differences in the severity of dental agenesis according to gender and to referrals from various geographic regions around Regensburg. The data were statistically analysed using two-tailed tests. The following teeth were most frequently missing: tooth 35 (5.9 per cent), 45 (5.1 per cent), 22 (4.0 per cent), 12 (3.6 per cent), 15 (3.1 per cent), and 25 (3.0 per cent). No statistically significant difference in gender was found for one to two missing permanent teeth (low degree), hypo- or oligodontia (severe degree), or cleft lip. The odds ratio (OR) of presenting with hypo- or oligodontia compared with no missing teeth was higher among subjects originating from geographic regions outside Regensburg than from those from Regensburg, and it was statistically significantly higher for patients from Passau {OR = 3.53 [95% confidence interval (CI) = 1.18-10.52]} and Landshut [OR = 3.65 (95% CI = 1.22-10.99)]. The high prevalence and severe degree of dental agenesis of permanent teeth found in these groups of patients likely reflects distinct referral patterns for patients originating from geographic regions outside Regensburg. These data reinforce the need for a specialized dental treatment centre with the capacity to adequately serve a large rural area in Eastern Bavaria.

EGFR (HER) family protein expression and cytogenetics in 219 squamous cell carcinomas of the upper respiratory tract: ERBB2 overexpression independent prediction of poor prognosis.

OBJECTIVE: To retrospectively evaluate the prognostic impact of gene status and protein expression of receptor tyrosine kinases of the HER (human epidermal growth factor receptor related) family in relation to established clinicopathologic parameters in squamous cell carcinomas of the upper respiratory tract. STUDY DESIGN: Immunohistochemistry and fluorescence in situ hybridization for HER1-4 and the proliferation marker Ki-67 was performed in 219 cases of head and neck squamous cell carcinomas and related to long-term clinical follow-up. Additionally, the prognostic impact of chromosomal instability was analyzed. RESULTS: High expression of HER1 and HER2 was present in 49.4% and 6.6% of tumors, respectively. Expression of HER3 and HER4 appeared negative or inconspicuous. A gene amplification of HER1 occurred in 5.2% of tumors, whereas none of the tumors showed an amplification of HER2-4 loci. In univariate overall survival analysis a negative prognostic impact could be demonstrated for high expression of HER2 (p < 0.01), advanced local tumor growth (p < 0.01), lymph node metastasis (p < 0.01), presence of residual tumor after surgical therapy (p < 0.01), high proliferative activity (Ki-67; p = 0.02) and high chromosomal instability (p = 0.01). According to the multivariate analysis, the strongest negative predictors of survival were advanced tumor growth (p < 0.01), presence of residual tumor (p < 0.01), high expression of HER2 (p < 0.01) and chromosomal instability (p = 0.03). CONCLUSION: Overexpression of HER2 and presence of chromosomal instability harbor an additional prognostic impact on disease-specific survival and prove to be independent negative prognostic factors in head and neck squamous cell carcinomas.

The differentiation and gene expression profile of human dental follicle cells.

Human dental follicle cells (DFCs) are progenitor cells. Recent studies supposed that osteogenic differentiation of DFCs is controlled by growth factors such as BMP2 and IGF2, but their influence on the differentiation of DFCs has not been investigated in detail. We examined DFCs after the induction of osteogenic differentiation with BMP2, IGF2 and a standard osteogenic differentiation medium (ODM) with dexamethasone. The alkaline phosphatase (ALP) activity and the calcium accumulation demonstrated osteogenic differentiation after all treatments, but with the most effective differentiation by ODM. Interestingly, markers of the process of osteoblast differentiation were much higher up-regulated in BMP2- or IGF2-treated cells than in ODM-treated cells. To evaluate the reason of these differences, we compared genome-wide expression profiles at an early stage of differentiation. Chondroblast markers in BMP2-differentiated cells and general markers for cell differentiation/proliferation in IGF2-treated cells were significantly regulated. However, ODM-treated DFCs expressed late markers of osteogenic-differentiated DFCs such as the transcription factor ZBTB16 that is not expressed in BMP2- or IGF2-differentiated cells. Importantly, although the BMP-antagonist noggin (NOG) diminishes the phosphorylation of SMAD1 in DFCs, it did not inhibit osteogenic differentiation by ODM and the expression of ZBTB16. In conclusion, this study demonstrates that osteogenic differentiation of DFCs can be stimulated with all tested inducers but also independently of BMP signaling. To evaluate this mechanism, the transcription factor ZBTB16 is a target for further investigations.

Resorbable versus titanium osteosynthesis devices in bilateral sagittal split ramus osteotomy of the mandible - the results of a two centre randomised clinical study with an eight-year follow-up.

BACKGROUND: This study was conducted to compare the long-term clinical outcome of patients with jaw disproportion who had had fixation with resorbable polylactic acid containing positioning screws with those who had had titanium positioning screws in bilateral sagittal split ramus osteotomy of the mandible (BSSO). PATIENTS AND METHODS: Sixty-six patients with isolated mandibular jaw disproportion were included and divided randomly into two treatment groups (resorbable and titanium). Patients were followed for 8 years postoperatively using a standardised protocol. Material-specific complications, functional problems and clinical findings within the former operation field were documented. Treatment stability was determined by occlusion criteria. RESULTS: Thirty-four patients (54%) were followed until the end of the study. No significant differences were observed in the outcomes of patients in the two groups related to the materials used for osteosynthesis or the long-term treatment stability. During the study, no foreign body reactions were observed. CONCLUSION: This study showed that resorbable and titanium positioning screws were equally effective as fixation devices in sagittal split osteotomy. Complete resorption of the resorbable screws could not be verified because of the absence of histological examination, however, the use of resorbable positioning screws can be considered as an alternative osteosynthesis material to conventional titanium osteosynthesis devices in sagittal split osteotomy.

TGF-beta stimulates glial-like differentiation in murine dental follicle precursor cells (mDFPCs).

Dental stem cells such as dental follicle precursor cells (DFPCs) are capable of neural-like differentiation. However, compared to neuroectodermal progenitor cells such as murine retinal progenitor cells (mRPCs) they show only a limited capacity for glial cell differentiation. In this study we tested the influence of cell signaling on glial differentiation of mDFPCs. These cells were treated with inhibitors and activators of the Sonic hedgehog-, the Wnt/beta-Catenin-, and the TGF-beta-pathway. After incubation only an activation of the TGF-beta-pathway showed a remarkable glial-like cell differentiation. In contrast gene expression of neural cell markers was not regulated. In conclusion, TGF-beta improved glial-like, but not neural-like, differentiation of mDFPCs.

S100A8 cellular distribution in normal epithelium, hyperplasia, dysplasia and squamous cell carcinoma and its concentration in serum.

OBJECTIVE: To investigate the function of S100A8, a member of the calcium-binding S100 protein family, in oral tumorigenesis. We analyzed its cellular distribution and its serum level in patients with squamous cell carcinoma and normal controls. STUDY DESIGN: We investigated the histopathologic features by tissue microarrays (TMAs) including 8 normal, 66 hyperplastic and dysplastic and 26 oral squamous cell carcinoma (OSCC) tissue cores. The serum level of S100A8 was measured by an enzyme-linked immunosorbent assay using 33 healthy volunteers, 20 patients with hyperproliferative lesions and 23 patients with OSCC. RESULTS: The TMA analysis resulted in different findings. The strongest expression of S100A8 was found in severe dysplasias and carcinoma in situ. In tumor tissue an increased expression occurred only focally. In the normal tissue cores the epithelium showed a moderate reaction, but basal and parabasal cells were completely negative. The serum levels of S100A8 were marginally reduced in cancer patients. The expression between healthy controls and patients with hyperproliferative lesions displayed no difference. CONCLUSION: The expression of S100A8 is helpful only in the transition from severe dysplastic tissue to cancer.

Bone resorption and complications in alveolar distraction osteogenesis.

Distraction osteogenesis presents an alternative procedure for augmentation of atrophic alveolar bone prior to inserting dental implants. The aim of this retrospective study was to evaluate complications of this method with specific focus on bone resorption during the consolidation period and the follow-up period after dental implant insertion into distracted bone. Thirty partially edentulous patients underwent a total of 36 vertical alveolar distractions with an extraosseous distraction system. Eleven devices were placed in the maxilla and 25 in the mandible. Eighty-two dental implants were inserted after a mean consolidation period of 4.5 months. Treatment results were evaluated by means of panoramic radiographs for distraction follow-up and periapical radiographs for implant follow-up. The mean length of the transport segment was 19 mm. The average alveolar height achieved was 6.4 mm with a mean resorption of 1.8 mm (21.1%) at the time of dental implant insertion. Main problems comprised oral displacement of the transport segment (n = 15) and inadequate soft tissue extension (n = 13). Eighty-two dental implants were inserted with an overall survival rate of 95.1% after 45.8 months. For periimplant marginal bone, an average resorption of 3.5 mm was recorded 50.4 months after implant insertion. Although alveolar distraction osteogenesis seems to be an effective tool to treat vertical defects of the alveolar ridge, it is not an uncomplicated procedure. A combination with vestibular augmentation of autogenous bone grafts should be considered. Overcorrection of 20% may compensate bone relapse during the consolidation period of the distracted alveolar bone. Further bone resorption after dental implantation is common.

Stromal laminin chain distribution in normal, hyperplastic and malignant oral mucosa: relation to myofibroblast occurrence and vessel formation.

BACKGROUND: The contribution of stromal laminin chain expression to malignant potential, tumour stroma reorganization and vessel formation in oral squamous cell carcinoma (OSCC) is not fully understood. Therefore, the expression of the laminin chains alpha2, alpha3, alpha4, alpha5 and gamma2 in the stromal compartment/vascular structures in OSCC was analysed. METHODS: Frozen tissue of OSCC (9x G1, 24x G2, 8x G3) and normal (2x)/hyperplastic (11x) oral mucosa was subjected to laminin chain and alpha-smooth muscle actin (ASMA) immunohistochemistry. Results were correlated to tumour grade. The relation of laminin chain positive vessels to total vessel number was assessed by immunofluorescence double labelling with CD31. RESULTS: Stromal laminin alpha2 chain significantly decreases and alpha3, alpha4, alpha5 and gamma2 chains and also ASMA significantly increase with rising grade. The amount of stromal alpha3, alpha4 and gamma2 chains significantly increased with rising ASMA positivity. There is a significant decrease in alpha3 chain positive vessels with neoplastic transformation. CONCLUSIONS: Mediated by myofibroblasts, OSCC development is associated with a stromal up-regulation of laminin isoforms possibly contributing to a migration promoting microenvironment. A vascular basement membrane reorganization concerning alpha3 and gamma2 chain laminins during tumour angioneogenesis is suggested.

Comparison of human dental follicle cells (DFCs) and stem cells from human exfoliated deciduous teeth (SHED) after neural differentiation in vitro.

Dental stem cells from human exfoliated deciduous teeth (SHED) and dental follicle cells (DFCs) are neural crest-derived stem cells from human dental tissues. Interestingly, SHED and DFCs can successfully differentiate into neuron-like cells. We hypothesized that SHED and DFCs have the same neural cell differentiation potentials. To evaluate neural cell differentiation, we cultivated SHED and DFCs in four different serum-replacement media (SRMs) and analyzed cell morphology, cell proliferation, and gene expression patterns before and after differentiation. In a standard cell culture medium, SHED and DFCs have not only similar cell morphologies, but they also have similar gene expression patterns for known stem cell markers. However, only SHED expressed the neural stem cell marker Pax6. After cultivation in SRMs, cell proliferations of DFCs and SHED were reduced and the cell morphology was spindle-like with long processes. However, differentiated DFCs and SHED had different neural cell marker expression patterns. For example, gene expression of the late neural cell marker microtubule-associated protein 2 was upregulated in DFCs and downregulated in SHED in SRM with the B27 supplement. In contrast, SHED formed neurosphere-like cell clusters in SRM with the B27 supplement, epidermal growth factor, and fibroblast growth factor-2. Moreover, SHED differentially expressed the glial cell marker glial fibrillary acidic protein, which in contrast was weakly or not expressed in DFCs. In conclusion, SHED and DFCs have different neural differentiation potentials under the same cell culture conditions.

Impact of MAGE-A antigens on taxane response in oral squamous cell carcinoma.

MAGE-A antigens are a subgroup of cancer/testis antigens that are exclusively expressed in malignant cells. Only scarce information on the function of MAGE-A antigens is available. There is some evidence that they may influence the response to chemotherapeutic drugs. This study aimed to evaluate the impact of the MAGE-A antigen subgroups MAGE-A2, -A3, -A4 and -A6 on oral squamous cell carcinoma cell lines treated with docetaxel and paclitaxel. Five oral squamous cell carcinoma cell lines were characterized for their quantitative expression of MAGE-A2, -A3, -A4 and -A6. The cell lines were treated with concentrations ranging from 0.025 to 0.8 µM of docetaxel and paclitaxel. The amount of viable cells after 24 and 48 h was measured. The measurements were statistically correlated with MAGE-A expression. All cell lines responded to docetaxel and paclitaxel. One cell line showed a statistically significant weaker response to the taxane treatment. This cell line was the only one that expressed MAGE-A4. MAGE-A4 has a statistically significant impact on the tumour response to docetaxel and paclitaxel in oral squamous cell carcinoma. This may influence treatment options and the course of the disease. Therefore, patients should be evaluated for MAGE-A4 expression before treatment with taxanes.

Feasibility of alloplastic mandibular reconstruction in patients following removal of oral squamous cell carcinoma.

INTRODUCTION: Microvascular bone grafts have evolved as the preferred technique for mandibular reconstruction in irradiated tumour patients. However immediate reconstruction by bridging plates remains an option for patients whose clinical condition is not favourable for microsurgical reconstruction. This retrospective study evaluates the performance of alloplastic mandibular reconstruction in patients following removal of oral squamous cell carcinoma. PATIENTS AND METHODS: Three hundred and thirty-four patients with primary (biopsy proven) oral squamous cell carcinoma without distant metastasis (stages II-IV), who were all treated by segmental mandibular resection and reconstruction by means of a titanium bridging plate were included. Two hundred and seventy-two patients received preoperative treatment, consisting of concomitant radiochemotherapy (RCT) (n=228), chemotherapy (n=34) and radiotherapy (n=10). Median follow-up was 5.1 years (min 0.3, max 18.0). RESULTS: The median 2-year-disease-specific survival rate (DSS) was 81.6%. Five-year-DSS and 10-year-DSS was 71.8% and 62.0%, respectively. One hundred and thirty-six plates were removed due to infection with intra- and/or extraoral exposure, seven plates because of fracture. Preoperative RCT (p=0.027), mandibular defects including the symphysis (p=0.016) and heavy smoking at the time of diagnosis (p=0.042) were associated with infection-related failure of the reconstruction plates. CONCLUSION: Reconstruction of mandibular defects with titanium bridging plates seems crucial in heavy smoking tumour patients with preoperative RCT as well as in mandibular defects including the symphysis.

Two modifications in the treatment of keratocystic odontogenic tumors (KCOT) and the use of Carnoy's solution (CS)--a retrospective study lasting between 2 and 10 years.

This retrospective study aimed at evaluating the recurrence rates of keratocystic odontogenic tumors (KCOTs) that were enucleated with and without the application of Carnoy's solution (CS). The study included 36 KCOTs treated between 1996 and 2006. Recurrence rates were investigated in correlation with the respective treatment method applied. Additionally, any damage to the inferior alveolar nerve associated with treatment was analyzed. Treatments consisted of enucleation with (38.9%) or without (61.1%) the application of CS. Median follow-up was 4.5 years. Single enucleation showed a recurrence rate of 50%, but the additional application of CS reduced the recurrence rate to 14.3%. No detrimental effects of CS on the mandibular nerve were detected. Enucleation plus the application of CS reduced the recurrence rate of KCOTs compared with simple enucleation. The application of CS did not cause any damage to the mandibular nerve.