Multiple recurrent follicular dendritic cell sarcoma: A case report

Tumors of the follicular dendritic cells (FDC-Sarcoma) represent a rare entity with only about 200 cases reported worldwide. The majority (60%) of cases arise primarily in cervical, abdominal or axillar lymph nodes, but extra nodal origin from secondary lymphatic tissue like the tonsils, Waldeyer's ring or MALT is also common (40%). The current report presents a characteristic course of a cervical FDC-Sarcoma, with its challenges in establishing the initial diagnosis and the struggle for therapeutic options. The FDC-Sarcoma presented recurrently for four times. Three different university hospitals in Germany were involved in the patients' treatment. Due to the patients' refusal, no adjuvant therapy was applied. In the end, a neck dissection was performed. The patient was closely followed up and has been recurrence-free for 10 years. This case suggests operative resection in combination with a neck dissection as a curative therapy for FDC-Sarcoma of the head and neck.

Evaluation of Biocompatibility of Different Membrane Surfaces Using Unrestricted Somatic Stem Cells

BACKGROUND/AIM

Results of Guided Bone Regeneration (GBR) primarily depend on the membrane used. The aim of this study was to compare biocompatibility of different absorbable and non-absorbable membranes by using unrestricted somatic stem cells (USSCs) as an indicator for biocompatibility.

MATERIALS AND METHODS

Five absorbable membranes (Bio-Gide®, RESODONT®, GENTA-FOIL resorb®, BioMend® and BioMend® Extend™) and one non-absorbable alternative (GORE-TEX®) were colonized with USSCs. After 24 h, 3 days and 7 days, cell proliferation, cell viability, and cytotoxicity were assessed. Moreover, cell morphology was evaluated by electron microscopy.

RESULTS

Significantly higher cell proliferation and cell viability rates were observed in Bio-Gide® and RESODONT® membranes. Cell toxicity was highest on GENTA-FOIL resorb® membranes. The electron microscopical assessment showed a better cell attachment on porous surfaced membranes.

CONCLUSION

This study shows that USSCs can be used for assessments of biocompatibility, and that absorbable membranes with collagenous composition and porous structure tend to positively impact biocompatibility and enhance cell proliferation.

Release kinetics of the model protein FITC-BSA from different polymer-coated bovine bone substitutes

Background

Controlled release of proteins bound to conventional bone substitutes is still insufficient. Therefore, this study evaluates in-vitro release kinetics of the model protein FITC-BSA (fluorescein conjugated bovine serum albumine) from insoluble bovine collagenous bone matrices (ICBM) with different polymer coatings. Analyzes aim at comparing FITC-BSA release from uncoated versus coated ICBM over time to find bone substitute coatings with consistent release profiles.

Methods

Release kinetics of FITC-BSA from uncoated as well as coated ICBM with five different polymers (RESOMER R 203 H, RG 503 H, RG 504 H, RG 505, L 206 S) were measured over a period of 11 days (d). Measurements were conducted after 6 h (h), 12 h, 24 h, 3 d, 5 d, 7 d, 9 d and 11 d with six samples for each coated ICBM. Two groups were formed (1) with and (2) without medium change at times of measurement. For each group ANOVA with post-hoc Bonferroni testing was used. Scanning electron microscopy assessed morphologic differences between ICBM coating.

Results

In group 1 approx. 70% of FITC-BSA release from uncoated ICBM occurred after 6 h compared to approx. 50% in group 2. Only polymers with medium inherent viscosity, i.e. RESOMER RG 503 H, constantly showed significantly more FITC-BSA release throughout 11 d than uncoated ICBM (p = 0.007). The same was found for group 2 (p = 0.005). No significant differences between PLA and PLGA polymers were found. Scanning electron microscopy results indicate a weak adhesion of polymer coatings to ICBM explaining its rather weak retentive effect on overall FITC-BSA release.

Conclusions

Medium molecular size polymers reduce the overall released FITC-BSA from ICBM over time. In clinical practice these polymers may prove ideal for bone substitute materials.

Evaluation of the oral health-related quality of life in patients with odontogenic fascial space abscesses and underlying conditions - a prospective questionnaire-based study

Background

Oral Health-Related Quality of Life (OHRQoL) is an important aspect of quality of life. Acute illnesses, as well as chronic diseases, can have a strong, persisting impact on an individual’s quality of life. This study evaluates OHRQoL of patients with odontogenic fascial space abscesses, the underlying conditions, and its consequences for clinical routines.

Methods

The research group consisted of patients presenting themselves to the emergency room or elective clinic of the Department for Cranio-Maxillofacial and Plastic Surgery (n = 94). The validated German version of the Oral Health Impact Profile (OHIP-G) and additional questions (including habits and routines in oral hygiene) with an anamnestic recall period of 1 month was used to evaluate OHRQoL shortly after emergency treatment (baseline) and again after 3–6 months’ follow-up. Ninety-four patients completed the questionnaire at baseline, 54 completed both questionnaires. Additionally, OHIP-G scores were compared to those of the non-impacted general German population.

Results

Results showed a significant difference in OHIP-G scores from baseline to follow-up (p = 0.001). Overall a mean of 55.24 (±37.02) points was scored at baseline and a mean of 37.02 (±35.79) points was scored at follow-up. Patients scored higher than participants of a representative study of the general German population.

Conclusion

Overall results suggest an increase in OHRQoL 3–6 months after acute treatment. Nevertheless, OHRQoL of patients suffering from odontogenic fascial space abscesses seems to remain generally lower than the OHRQoL of the general German population.

Trial registration

Trial registration: Central Study Register of the University Hospital Duesseldorf, Registration-ID: 2016085405. Registered 24 August 2016.

Pathogenesis of medication-related osteonecrosis of the jaw: a comparative study of in vivo and in vitro trials

Objective This study was performed to determine whether the results of prevailing in vivo and in vitro studies offer a reliable model for investigation of medication-related osteonecrosis of the jaw (MRONJ). Methods Embase, Medline, and the Cochrane Library were searched for articles published from September 2003 to June 2017 involving experimental approaches to the pathogenesis of MRONJ. In vivo and in vitro trials were analyzed with respect to the scientific question, study design, methodology, and results. Results Of 139 studies, 87, 46, and 6 conducted in vivo, in vitro, and both in vivo and in vitro experiments, respectively. Rats, mice, dogs, minipigs, sheep, and rabbits were the preferred animal models used. Osteoblasts, osteoclasts, fibroblasts, keratinocytes, macrophages, and human umbilical vein endothelial cells were the preferred cell types. Zoledronate, alendronate, ibandronate, and risedronate were the most frequent bisphosphonates used. MRONJ was most reliably induced in minipigs because of the close relationship with human bone physiology. In vitro studies showed that reduced viability, growth, and migration of cells in the bone and soft tissues were causative for MRONJ. Other than exposed jawbone after tooth extraction, no reliable cofactors were found. Conclusion The minipig is the most suitable animal model for MRONJ.

Vertical bone regeneration using rhBMP-2 and VEGF

Background

Sufficient vertical and lateral bone supply and a competent osteogenic healing process are prerequisities for the successful osseointegration of dental implants in the alveolar bone. Several techniques including autologous bone grafts and guided bone regeneration are applied to improve quality and quantity of bone at the implantation site. Depending on the amount of lacking bone one- or two-stage procedures are required. Vertical bone augmentation has proven to be a challenge particularly in terms of bone volume stability. This study focuses on the three dimensional vertical bone generation in a one stage procedure in vivo. Therefore, a collagenous disc-shaped scaffold (ICBM = Insoluble Collagenous Bone Matrix) containing rhBMP-2 (Bone Morphogenetic Protein-2) and/or VEGF (Vascular Endothelial Growth Factor) was applied around the coronal part of a dental implant during insertion. RhBMP-2 and VEGF released directly at the implantation site were assumed to induce the generation of new vertical bone around the implant.

Methods

One hundred eight titanium implants were inserted into the mandible and the tibia of 12 mini pigs. Four experimental groups were formed: Control group, ICBM, ICBM + BMP-2, and ICBM + BMP-2 + VEGF.

After 1, 4 and 12 weeks the animals were sacrificed and bone generation was investigated histologically and histomorphometrically.

Results

After 12 weeks the combination of ICBM + rhBMP2 + VEGF showed significantly more bone volume density (BVD%), a higher vertical bone gain (VBG) and more vertical bone gain around the implant (PVBG) in comparison to the control group.

Conclusion

By using collagenous disc-shaped matrices in combination with rhBMP-2 and VEGF vertical bone can be generated in a one stage procedure without donor site morbidity. The results of the presenting study suggest that the combination of rhBMP-2 and VEGF applied locally by using a collagenous carrier improves vertical bone generation in vivo. Further research is needed to establish whether this technique is applicable in clinical routines.

Immunohistochemical detection of lymph node-DTCs in patients with node-negative HNSCC

This study was performed to systematically assess the prevalence, topography and prognostic impact of disseminated tumor cells (DTCs) in lymph nodes (LN) of patients with primary, regional and distant metastasis-free head and neck squamous cell carcinoma (HNSCC) who underwent resection with elective neck dissection. From the routinely processed resection specimen, we could prospectively analyze a total of 1.137 exactly mapped LNs of 50 pN0-HNSCC patients, classified as tumor free by routine histopathology. Three immunohistochemistry (IHC) assays using antibodies directed against CK5/14, a broad spectrum of CKs (1-8, 10, 14-16 and 19), and CD44v6, respectively, were applied on 4.190 LN sections to detect DTCs. The IHC results were correlated with clinicopathologic parameters and clinical follow-up data. We detected seven micrometastases (MM) in five patients and 31 DTCs in 12 patients. Overall, 15 (30%) patients were positive for DTCs or MMs. Strikingly, the anatomical distribution of LN affected with DTCs was not random, but was dependent on the lateralization of the primary tumor and clustered significantly most proximal to the primary tumor. None of the investigated patients developed loco-regional lymphatic or distant metastasis during the mean follow-up period of 71 months. Our results reveal clinically occult tumor cell dissemination as an early and frequent event in HNSCC. Considering that higher rates of recurrences in therapeutic LN dissection concepts have been reported than in elective neck dissection strategies, our DTC-data support to perform elective neck dissections, since they appear to be effective in preventing loco-regional lymphatic recurrence from LN DTCs or MMs.

Biocompatibility of membranes with unrestricted somatic stem cells

AIM

The biocompatibility of human osteoblasts (HOB) and human unrestricted somatic stem cells (USSCs) with membranes (BioGide®, GORE-TEX®, GENTA-FOIL resorb®, RESODONT®, BioMend®, BioMend® Extend™) was evaluated.

MATERIALS AND METHODS

After osteogenic differentiation (dexamethasone, ascorbic acid and β-glycerolphosphate) cells were seeded on membranes. On days 1, 3 and 7, attachment, proliferation, cell vitality, cytotoxicty and cell morphology were analyzed.

RESULTS

Cells on BioGide® and RESODONT® exhibited significantly higher attachment (p<0.005) and proliferation (p<0.005). On BioMend® cells showed a significantly higher attachment compared to BioMend® Extend™ (p<0.005), whereas on BioMend® Extend™ cells had significantly higher proliferation (p<0.005). The vitality of cells was significantly better on BioGide® and RESODONT® (p<0.005). There were no significant differences between USSCs and HOBs. Scanning electron microscopy confirmed these results.

CONCLUSION

BioGide® and RESODONT® had the best biocompatibility and are appropriate membranes for use in stem cell-derived regeneration of bone.

Bilateral multifocal Warthin's tumors in upper neck lymph nodes. Report of a case and brief review of the literature

Cystadenolymphomas (Warthin's tumors) are the second most frequent lesions of the parotid gland. Due to their benign clinical behavior, the low rates of recurrence and malignant transformation they were classified as tumor-like lesions. In addition, a polyclonal growth of the epithelial components of the tumor could be detected. Warthin's tumors occur bilateral in 7-10%, whereas a multifocal appearance is extremely rare. Even if the pathogenesis is still unclear a heterotopia of salivary tissue during embryogenesis is the most likely explanation for the origin of these tumors in the upper neck and periparotideal region. Here we present a rare case of bilateral, multifocal, extraglandular Warthin's tumors in lymph nodes of the upper neck and give a brief review of the literature. If a primary malignancy can be excluded by a careful staging procedure prior to the operation an isolated excision of the lesions of the neck is the adequate treatment.

Current findings regarding zirconia implants

PURPOSE

The present article aims to analyze the available clinical data on the survival and success rate of dental zirconia implants (ZI).

MATERIAL AND METHOD

Studies (2006-2011) listed in the bibliography were obtained by using the key words "zirconia, zirconium, implants, dental, clinical" and combinations of these in different databases and on the internet. These articles served as a basis for the article.

RESULTS

A total of 17 clinical studies were found, involving 1,675 implants and 1,274 patients. In 16 studies, one-piece implant systems were investigated. The survival rates for ZI range from 74-98% after 12-56 months, with success rates between 79.6-91.6% 6-12 months after prosthetic restoration. However, the design of most of the studies show considerable shortcomings, and only low evidence level.

CONCLUSION

The small number of studies and the limited period of observation permit only a qualified statement on the clinical success of ZI. The results available to date indicate that ZI are inferior to titanium implants (TI) with regard to survival and success rates. Well-conducted long-term studies are urgently needed to permit a meaningful assessment of the survival or success rates of ZI and a statement concerning their application as an alternative to TI.

Cartilage defect regeneration by ex vivo engineered autologous microtissue--preliminary results

We analysed the improvement of cartilage defect regeneration by the use of microspheres of autologous chondrocytes. Autologous chondrocytes from minipigs were cultured using the microsphere technology. Cartilage defects were surgically introduced to tibia-femoral joints. Tissue constructs were then implanted into defect sites. Histological, immunohistological and transmission electron microscopic analyses were performed. Histological and ultrastructural investigations of chondrospheres revealed a cartilage-like tissue formation, indicated by phenotypically differentiated chondrocyte-like cells surrounded by de novo synthesised chondrogenic extracellular matrix. Clinical inspection of defects demonstrated nearly complete cartilage regeneration in the microtissue treated defect sites, whereas controls exhibited irregular fibrous tissue formation. In vitro-expanded articular chondrocytes are able to form a microtissue capable of repairing cartilage defects in vivo, improving regeneration of cartilage defects.

Breast cancer in the lower jaw after reconstructive surgery with a pectoralis major myocutaneous flap (PMMC) -- a case report

For head and neck as well as for oromaxillofacial surgery, the use of the pectoralis major myocutaneous (PMMC) flap is a standard reconstructive technique after radical surgery for cancers in this region. We report to our knowledge for the first development of breast cancer in the PMMC flap in a 79 year old patient, who had undergone several operations in the past for recurring squamous cell carcinoma of the jaw. The occurrence of a secondary malignancy within the donor tissue after flap transfer is rare, but especially in the case of transferred breast tissue and the currently high incidence of breast cancer theoretically possible. Therefore preoperative screening mammography seems advisable to exclude a preexisting breast cancer in female patients undergoing such reconstruction surgery. Therapy for breast cancer under these circumstances is individual and consists of radical tumor resection followed by radiation if applicable and a standard systemic therapeutic regimen on the background of the patients individual prognosis due to the primary cancer.

Complications after oral surgery in patients with congenital or drug-induced bleeding disorders

BACKGROUND

Bleeding disorders (BD) can cause significant problems during or after surgical procedures of the oral cavity. The aim of this study was to explore the risk of bleeding following oral surgery in patients with BD.

PATIENTS AND METHODS

The medical records of all BD patients referred to the department of cranio- and maxillofacial surgery were reviewed.

RESULTS

Ninety-five patients (26 inherent BD, 69 taking antithrombotic drugs) were reviewed for this study. Interestingly, patients taking oral anticoagulants presented more bleeding complications than patients with inherent BD. During simple tooth extraction procedures, patients taking antithrombotic drugs had a higher risk of bleeding than patients with inherent BD.

CONCLUSION

The currently available treatment protocols for surgical treatment of dental patients with inherent BD suffice. However, our data indicates that there is still a need for clear guidelines for the treatment of patients taking antithrombotic drugs, especially phenprocoumon.

Evaluation of the quality of life of patients with maxillofacial defects after prosthodontic therapy with obturator prostheses

The purpose of this study was to investigate how patients with maxillofacial defects evaluate their quality of life after maxillectomy and prosthodontic therapy with obturator prostheses. 43 patients were included in the study (25 female, 18 male). 31 (72%) patients completed a standardized questionnaire of 143 items and then answered additional questions in a standardized interview. Global quality of life after prosthodontic therapy with obturator prostheses was 64% (±22.9) on average. Functioning of the obturator prosthesis, impairment of ingestion, speech and appearance, the extent of therapy, and the existence of pain had significant impact on the quality of life (p<0.005). Orofacial rehabilitation of patients with maxillofacial defects using obturator prostheses is an appropriate treatment modality. To improve the situation of patients prior to and after maxillectomy sufficient information about the treatment, adequate psychological care and speech therapy should be provided.

Improvement of the cell-loading efficiency of biomaterials by inoculation with stem cell-based microspheres, in osteogenesis

In critical-size bone defects, autologous or allogenic cells are required in addition to compatible biomaterials for the successful defect healing. State of the art inoculation methods of biomaterials are based on the application of cell suspensions to the biomaterial. However, only less amounts of cells can be applied and sufficient adhesion to the material is required. Therefore, it was investigated whether the advantages of stem cell-based microspheres and insoluble collagenous bone matrix (ICBM) scaffolds can be combined which can lead to an advancement in cell seeding on biomaterials. Microspheres were produced from unrestricted somatic stem cells from human umbilical cord blood and were mounted on ICBM scaffolds. Following the incubation with osteogenic or control medium, the constructs were analyzed histologically after 3, 7, 14, and 28 days. Alizarin Red S and von Kossa staining revealed microsphere mineralization after 3 days in osteogenic and after 14 days in control medium. Meanwhile, a time-dependent increase in tissue, growing out of the microspheres, was detected. Our results provide evidence that microsphere-ICBM constructs are promising candidates for approaches of bone regeneration. They allow the transfer of substantially high numbers of cells in partially mineralized constructs.

Biocompatibility of osteogenic predifferentiated human cord blood stem cells with biomaterials and the influence of the biomaterial on the process of differentiation

Modern cell-based bone reconstruction therapies offer new therapeutic opportunities and tissue engineering represents a more biological-oriented approach to heal bone defects of the skeleton. Human unrestricted somatic stem cells (USSCs) derived form umbilical cord blood offer new promising aspects e.g., can differentiate into osteogenetic cells. Furthermore these cells have fewer ethical and legal restrictions compared to embryonic stem cells (ESCs). The purpose of this study was to evaluate the compatibility of osteogenic pre-differentiated USSCs with various biomaterials and to address the question, whether biomaterials influence the process of differentiation of the USSCs. After osteogenic differentiation with DAG USSCs were cultivated with various biomaterials. To asses the biocompatibility of USSCs the attachment and the proliferation of the cells on the biomaterial were measured by a CyQUANT(®) assay, the morphology was analyzed by scanning electron microscopy and the influence of the gene expression was analyzed by real time PCR. Our results provide evidence that insoluble collagenous bone matrix followed by β-tricalciumphosphate is highly suitable for bone tissue engineering regarding cell attachment and proliferation. The gene expression analysis indicates that biomaterials influence the gene expression of USSCs. These results are in concordance with our previous study with ESCs.

Solitary submucous neurofibroma of the mandible: review of the literature and report of a rare case

Solitary neurofibroma is a rare benign non-odontogenic tumor. Particularly in the oral cavity, neurogenic tumors are rare, especially if they are malignant. Neurofibromas may present either as solitary lesions or as part of the generalised syndrome of neurofibromatosis or von Recklinghausen's disease of the skin. Clinically, oral neurofibromas usually appear as pediculated or sessile nodules, with slow growth and mostly without pain. The diagnosis can be confirmed by histological examination. Neurofibromas are immunopositive for the S-100 protein, indicating its neural origin. Treatment is surgical and the prognosis is excellent. For illustration a rare case of a solitary neurofibroma in the mandible is presented.

Osseointegration of zirconia implants compared with titanium: an in vivo study

Background

Titanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental role in osseointegration, various chemical and physical surface modifications have been developed to improve osseous healing. Zirconia-based implants were introduced into dental implantology as an altenative to titanium implants. Zirconia seems to be a suitable implant material because of its tooth-like colour, its mechanical properties and its biocompatibility. As the osseointegration of zirconia implants has not been extensively investigated, the aim of this study was to compare the osseous healing of zirconia implants with titanium implants which have a roughened surface but otherwise similar implant geometries.

Methods

Forty-eight zirconia and titanium implants were introduced into the tibia of 12 minipigs. After 1, 4 or 12 weeks, animals were sacrificed and specimens containing the implants were examined in terms of histological and ultrastructural techniques.

Results

Histological results showed direct bone contact on the zirconia and titanium surfaces. Bone implant contact as measured by histomorphometry was slightly better on titanium than on zirconia surfaces. However, a statistically significant difference between the two groups was not observed.

Conclusion

The results demonstrated that zirconia implants with modified surfaces result in an osseointegration which is comparable with that of titanium implants.

Behavior of osteoblastic cells cultured on titanium and structured zirconia surfaces

BACKGROUND

Osseointegration is crucial for the long-term success of dental implants and depends on the tissue reaction at the tissue-implant interface. Mechanical properties and biocompatibility make zirconia a suitable material for dental implants, although surface processings are still problematic. The aim of the present study was to compare osteoblast behavior on structured zirconia and titanium surfaces under standardized conditions.

METHODS

The surface characteristics were determined by scanning electron microscopy (SEM). In primary bovine osteoblasts attachment kinetics, proliferation rate and synthesis of bone-associated proteins were tested on different surfaces.

RESULTS

The results demonstrated that the proliferation rate of cells was significantly higher on zirconia surfaces than on titanium surfaces (p < 0.05; Student's t-test). In contrast, attachment and adhesion strength of the primary cells was significant higher on titanium surfaces (p < 0.05; U test). No significant differences were found in the synthesis of bone-specific proteins. Ultrastructural analysis revealed phenotypic features of osteoblast-like cells on both zirconia and titanium surfaces.

CONCLUSION

The study demonstrates distinct effects of the surface composition on osteoblasts in culture. Zirconia improves cell proliferation significantly during the first days of culture, but it does not improve attachment and adhesion strength. Both materials do not differ with respect to protein synthesis or ultrastructural appearance of osteoblasts. Zirconium oxide may therefore be a suitable material for dental implants.

Osseointegration of zirconia implants: an SEM observation of the bone-implant interface

Background

The successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics, biocompatibility, and bright tooth-like color, zirconia (zirconium dioxide, ZrO₂) has the potential to become a substitute for titanium as dental implant material. The present study aimed at investigating the osseointegration of zirconia implants with modified ablative surface at an ultrastructural level.

Methods

A total of 24 zirconia implants with modified ablative surfaces and 24 titanium implants all of similar shape and surface structure were inserted into the tibia of 12 Göttinger minipigs. Block biopsies were harvested 1 week, 4 weeks or 12 weeks (four animals each) after surgery. Scanning electron microscopy (SEM) analysis was performed at the bone implant interface.

Results

Remarkable bone attachment was already seen after 1 week which increased further to intimate bone contact after 4 weeks, observed on both zirconia and titanium implant surfaces. After 12 weeks, osseointegration without interposition of an interfacial layer was detected. At the ultrastructural level, there was no obvious difference between the osseointegration of zirconia implants with modified ablative surfaces and titanium implants with a similar surface topography.

Conclusion

The results of this study indicate similar osseointegration of zirconia and titanium implants at the ultrastructural level.

Compatibility of Embryonic Stem Cells with Biomaterials

Periodontal bone defects and atrophy of the jaws in an aging population are of special concern. Tissue engineering using embryonic stem cells (ESCs) and biomaterials may offer new therapeutic options. The purpose of this study is to evaluate the compatibility of ESCs with biomaterials and the influence of biomaterials on the osteogenic gene expression profile.

Therefore, ESCs are cultured with various biomaterials. The cytocompatibility of murine ESCs is measured regarding the proliferation of the cells on the materials by CyQUANT ® assay, the morphology by scanning electron microscopy, and the influence on the gene expression by real time PCR.

The results show that insoluble collagenous bone matrix, followed by β-tricalciumphosphate, is most suitable for bone tissue engineering regarding cell proliferation, and phenotype. The gene expression analysis indicates that biomaterials do influence the gene expression of ESCs.

Our results provide new insight into the cytocompatibility of ESCs on different scaffolds.

Principles of cartilage tissue engineering in TMJ reconstruction

Diseases and defects of the temporomandibular joint (TMJ), compromising the cartilaginous layer of the condyle, impose a significant treatment challenge. Different regeneration approaches, especially surgical interventions at the TMJ's cartilage surface, are established treatment methods in maxillofacial surgery but fail to induce a regeneration ad integrum. Cartilage tissue engineering, in contrast, is a newly introduced treatment option in cartilage reconstruction strategies aimed to heal cartilaginous defects. Because cartilage has a limited capacity for intrinsic repair, and even minor lesions or injuries may lead to progressive damage, biological oriented approaches have gained special interest in cartilage therapy. Cell based cartilage regeneration is suggested to improve cartilage repair or reconstruction therapies. Autologous cell implantation, for example, is the first step as a clinically used cell based regeneration option. More advanced or complex therapeutical options (extracorporeal cartilage engineering, genetic engineering, both under evaluation in pre-clinical investigations) have not reached the level of clinical trials but may be approached in the near future. In order to understand cartilage tissue engineering as a new treatment option, an overview of the biological, engineering, and clinical challenges as well as the inherent constraints of the different treatment modalities are given in this paper.

Additional use of DNA-image cytometry improves the assessment of resection margins

BACKGROUND

Despite the histopathologic findings of tumor-free margins, patients with oral squamous cell carcinoma (SCC) often suffer from local tumor relapse. The purpose of this study was to determine the prognostic value of DNA-image cytometry in the assessment of resection margins.

METHODS

DNA-image cytometry was performed in 40 SCC patients with histologically tumor-free resection margins. The follow-up period since the tumor resection was at least 3 years.

RESULTS

Twenty patients showed a locoregional relapse of the SCC. Fourteen of these patients had aneuploid cells in DNA-image cytometry. Two patients who were relapse-free revealed aneuploid cells too. The sensitivity of the adjuvant use of DNA-image cytometry was 70% and the positive predictive value was 87.5%.

CONCLUSIONS

The additional use of DNA-image cytometry is a reasonable tool for the assessment of the resection margins of SCCs. DNA-image cytometry could help to find the appropriate treatment option for the patients and thus might improve their prognosis.

Hyperbare Sauerstofftherapie bei Unterkiefer-Osteomyelitis

BACKGROUND

Chronic osteomyelitis of the jaw is a relapsing disease with multiple treatment strategies described in the literature. Hyperbaric oxygen therapy is one of them. The purpose of this study was to evaluate the clinical outcome of hyperbaric oxygen therapy in these patients.

METHOD

All patients with a chronic osteomyelitis of the mandible who received in our department hyperbaric oxygen therapy between 2000 and 2004 were included in this study. The clinical outcome (lack of symptoms e.g. pain, swelling, etc.) was the pivotal evaluation parameter. All patients were divided in three groups according to their medical history. Group 1: All patients with osteomyelitis of the mandible, who received no treatment before. Group 2: All patients with one local relapse, who received only antimicrobial treatment. Group 3: Patients with at least one local relapse after antimicrobial and surgical treatment.

RESULTS

27 patients were evaluated in this study. Seven out of 13 patients in group 1 were relapse free after performing 40 hyperbaric oxygen therapies. However, only 4 of 9 patients in group 3 were relapse free after treatment. In group 2 the hyperbaric oxygen therapy was successful particularly in the younger patients (3 of 4).

CONCLUSION

Adjuvant hyperbaric oxygen therapy was successful in the treatment of patients with chronic recurrent osteomyelitis of the mandible. Therefore, it is an treatment option which can avoid ablative surgery in some cases.

Dermoid cyst of the parotid gland—a case report and brief review of the literature

There is controversy over the frequency of dermoid cysts in the head and neck area. Some authors report that they are common, whereas others say that only 7% of such cysts occur in the head and neck area. In either case, they are extremely rare in the parotid gland. When PubMed is searched for 'dermoid cyst of the parotid gland', only 11 articles are listed. Only four of the articles written in English are case reports of dermoid cysts of the parotid gland. Due to the rarity of descriptions and the considerable diversity of swellings of the parotid gland diagnosis is difficult. Visualizing options like computed tomography, magnetic resonance imaging and ultrasound cannot give a conclusive preoperative diagnosis. This case report shows the challenges in diagnosis and gives a short review of the literature.

Ursachen, Therapie und Komplikationen bei der Frakturversorgung des Unterkiefers – eine retrospektive Analyse von 10 Jahren

BACKGROUND

Fractures of the mandible are a common form of facial injury. The aetiological factors associated with mandibular fractures and the trends in these factors over a 10-year period are reported.

METHODS

A retrospective survey was carried out of 724 patients presenting with a fracture of the mandible over the 10-year-period 1994-2003. Patients; records were reviewed and analyzed according to age, sex, cause of injury, anatomic site of fracture, treatment and postoperative complications.

RESULTS

Over the 10-year-period the rate of mandibular fractures remained constant (mean 40,7%). There were no changes in the age group (mean 33,3 years) or in the higher prevalence in male (male-female-ratio 2,3 : 1). The major causes of fractures were assaults (38,6%) and accidental fall (27,3%). The most common fracture site was the condylar region (47,0%) followed by the angle (29,4%). Most fractures were treated by closed reduction until 2002, thereafter surgical treatment increased noticeable. The complication rate was 8,9% and the most common complications were hardware exposure and infection.

CONCLUSION

Fractures of the mandible are a prevalent form of facial injury. Aetiological factors show no significant change over the 10-year-period. Complication-rate is low and will support the tendency towards surgical treatment.

Cell-based bone reconstruction therapies--cell sources

Over the last few decades, reconstructive surgery has shifted from a resection-oriented approach toward strategies focusing on repair and regeneration of tissues. As the main aim of maxillofacial reconstruction has been the restoration of bone form and function, surgeons used artificial tissue substitutes in the early decades of bone reconstruction. These artificial materials significantly improved the ability of surgeons to restore the form and, to some extent, the function of defective bones. Despite the fact that every artificial material has specific disadvantages, the use of biomaterials is a common treatment option in clinical practice even today. Due to the more detailed understanding that exists concerning transplantation of cells and tissues, autogenous grafts are the second mainstay in clinical practice. However, the main disadvantage of using autogenous grafts is donor site morbidity and donor shortage. Research is currently in progress into the use of cell-based approaches in reconstructive surgery, since cells are the driving elements for all repair and regeneration processes. Various cell populations have been reported on in the relevant literature. These cells can be classified according to differentiation capacity and the tissue from which they originated. In this review, unrestricted cells, multipotential progenitor cells, determined cells, and genetically modified cells are described systematically, and their advantages as well as limitations are discussed. (More than 50 references.)

Vergleich der osteogenen Potenz gentechnisch modifizierter BMP

BACKGROUND

Modification of the heparin binding site by alteration of the amino acid sequence of bone morphogenetic protein-2 (BMP-2) results in a change in the local retention time. The purpose of this study was to compare the osteogenic activity of T3 and T4, two mutants with increased binding capacity to heparin, and B2GDF-5 a mutant resulting from the fusion of the n-terminal amino acid sequence of BMP-2 and the c-terminal sequence of GDF-5 with wild-type BMP-2 in vivo.

MATERIAL AND METHODS

The proteins were coupled to an equine-derived collagen carrier and implanted in standardized critical size calvarial defects in adult rats. After 28 days, bone formation was evaluated radiographically and the new bone was characterized histologically.

RESULTS

Proteins T3 and T4 showed a higher osteogenic activity than BMP-2. Less new bone formation was observed with GDF-5 and B2GDF-5 than with-type BMP-2. No difference in bone formation was observed between GDF-5 and B2GDF-5.

CONCLUSION

Increased heparin binding capacity enhances osteogenic activity of BMP-2 in vivo. This might be due to a longer retention period in the tissue and thus better bioavailability. Replacement of the N-terminal amino acid sequence of GDF-5 by the corresponding sequence of BMP-2 did not result in an increased osteogenic activity as heparin binding capacity is not the main reason for the bioavailability of GDF-5.

Influence of platelet-rich plasma (PRP) on osteogenic differentiation of rat bone marrow stromal cells. An in vitro study

Recent clinical reports suggest that the application of an autologous blood plasma enriched with thrombocytes by centrifugal concentration (platelet-rich plasma: PRP) can enhance the formation of new bone. There are very fewin vitro or in vivo studies published on the efficiency of PRP. In this project a three dimensional cell culture system was used to compare PRP and rhBMP-2 in vitro. Marrow derived bone forming cells from Spraque-Dawley (SD) rats were seeded on porous collagenous carriers (d=5mm, h=3mm) at a density of 4 x 10(4) cells/carrier and exposed to different concentrations of PRP (platelet counts from 2.5 x 10(8)-1.6 x 10(7) platelets/culture), rhBMP-2 (300 ng) or plasma poor in thrombocytes (platelet-poor plasma, PPP). Cultures without additional supplements were used as controls. During a culture period of 21 days cell proliferation, alkaline phosphatase activity (ALP) and calcium content (days 18, 21) were measured in 3 day intervals.PRP showed a dose dependent stimulation of cell proliferation, while reducing ALP activity and calcium deposition in the culture. BMP-2 led to an opposite cell response and induced the highest ALP activity and mineral deposition. These data suggest that PRP inhibited osteogenic differentiation of marrow derived pre-osteoblasts in a dose dependent manner. PRP is not a substitute for BMP-2 in osteogenic induction.

[Comparative studies of sinus floor elevation with autologous or allogeneic bone tissue]

In 63 patients, 82 elevations of the maxillary sinus were performed. As augmentation, materials autografts from the iliac crest (combined with alveolar ridge augmentations in 16 sinus lifts) were transplanted in 39 cases and osteoinductive, allogeneic bone powder (AAA bone (autolyzed, antigen-extracted, allogeneic bone): n = 8, DFDBA (demineralized freeze-dried bone allograft) and/or Grafton (demineralized bone matrix gel): n = 35) were used in 43 cases. Some 4-6 months after implantation, osteoinductive, allogeneic (demineralized) bone implants showed radio-opaque areas as an equivalent of bone formation. Histological examinations revealed that osteoinductive implants were completely transformed into patients' own bone tissue. The average augmentation height after autograft transplantations was 14 (+/- 3) mm in comparison with 9 (+/- 3) mm after allograft implantations. Histologically as well as radiologically no differences of the bone quality could be determined between the two augmentation materials. Endoscopic controls showed, in both groups, nonirritated mucous membranes. On an average 2 endosseous implants (Bone Lock or ITI-screw implants) were inserted into the augmentated maxillary sinus floors in both groups. No osseointegration was achieved in 4 out of 67 dental implants when bone autografts were used and in 2 out of 74 dental implants of the allogeneic bone group. Patients with bone autografts suffered from postoperative complaints on an average of 19 (+/- 9) days (without consideration of 2 patients with postoperative complaints persisting for more than 90 days). The average postoperative complaints of recipients of allogeneic bone implants continued for 3 (+/- 5) days. The 13 patients who underwent an ambulant sinus lift procedure with allogeneic bone powder were already symptom-free several hours after the operation. Under critical consideration of all investigated parameters, osteoinductive bone implants are preferable to iliac bone autografts for maxillary sinus augmentations in those cases in which no additional alveolar ridge augmentation is required.