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1.
J Oral Biol Craniofac Res ; 12(1): 4-12, 2022.
Article in English | MEDLINE | ID: mdl-34745859

ABSTRACT

The classical treatment of craniosynostosis is based on the fundamental work by Tessier. However, developmental aspects suggest modified osteotomy lines like fronto orbito nasal advancement combined with a modified midfacial distraction. This also makes it possible to take assess the different distances of the anterior displacement of the individual parts of the skull. Pioneering in therapy is less the syndrome itself than the accompanying symptoms such as respiration and intracranial pressure. For brain release we recommended (Joos 1998) the osteoclastic procedure according to Powiertowsky (1974) within the first 6 months of life. For further treatment frontoorbito-nasal advancement and modified midface distraction seem to achieve better results in enlarging the inner nose and a more harmonious profile.

2.
J Oral Biol Craniofac Res ; 12(1): 13-21, 2022.
Article in English | MEDLINE | ID: mdl-34729346

ABSTRACT

E-learning programmes have become established in postgraduate oral medical education and training. Internet and literature researches show a variety of good concepts that provide an attractive alternative to face-to-face training. What is missing is an overall concept in which continuing education and training are offered in bundled form in various teaching and learning formats. We discuss the blended learning concept which offers the best options, which has been proven by scientific studies. Using the example of the International Medical College (IMC) at the University of Duisburg-Essen, a blended learning overall concept for postgraduate continuing education is presented.

3.
Int J Oral Maxillofac Surg ; 41(3): 309-12, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22014680

ABSTRACT

Melnick-Needles Syndrome (MNS) is a congenital syndrome associated with severe architectural disorder of the skeletal system that can cause significant effects on the craniofacial skeleton including poor aesthetics, impaired speech and masticatory problems. The authors report a case of a female patient who experienced masticatory constraint, hindered speech and functional problems related to a severe bite dysfunction due to the mandibular hypoplasia and the underlying bony architectural disorder associated with MNS. The patient underwent bilateral sagittal split osteotomy (BSSO) to correct her skeletal malocclusion and improve the characteristic aesthetics and speech. The inherent bony abnormalities with their altered collagen structure presented unique challenges to orthognathic surgery in this patient with an unpredictable bone healing process. In MNS patients a fragile trabecular bone structure and an increased bleeding tendency is thought to delay or forestall wound healing. The patient was treated successfully with BSSO and monocortical plate fixation following a well-established algorithm from orthodontic preparation to surgical protocol. A very satisfying outcome has been achieved, concerning functional rehabilitation and aesthetic improvement. A review of the literature revealed that little is known about bone regeneration and fracture healing in cases with MNS.


Subject(s)
Mandibular Diseases/surgery , Orthognathic Surgical Procedures/methods , Osteochondrodysplasias/surgery , Adolescent , Bone Plates , Esthetics, Dental , Female , Follow-Up Studies , Humans , Malocclusion, Angle Class II/surgery , Mandibular Advancement/instrumentation , Mandibular Advancement/methods , Mastication/physiology , Open Bite/surgery , Orthognathic Surgical Procedures/instrumentation , Osteotomy, Sagittal Split Ramus/instrumentation , Osteotomy, Sagittal Split Ramus/methods , Retrognathia/surgery , Speech Disorders/etiology , Treatment Outcome
4.
Oral Oncol ; 48(4): 355-60, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22154128

ABSTRACT

Head and neck cancer patients are prone to nutritional problems, partly due to the location and size of the disease, due to significant comorbidity and also often therapeutic intervention. Excessive weight loss after surgery reduces further the patients' physical resistibility and increases the complication rate for adjuvant radiation and or chemotherapy. Possible effective interventions are dietary counseling, nutritional supplements or drug interventions. Aim of our research was to reveal reliable clinical predictive parameters, which calculate risks as the reduced nutritional state against the possible complications of PEG insertion and finally define an algorithm for pre-therapeutic PEG insertion to optimize the general treatment conditions by sufficient nutrition. We explored the data of 152 patients in a time period from 2005 to 2010 considering age, gender, body mass index, staging, size and localization of the tumor or need for a neck dissection. The decisive predictive parameters are: body mass index, size and localization of tumor, lymph node affection, resection of the root of the tongue or the oropharynx region and performance of a neck dissection. In this retrospective study we established a prediction model that allows a substantiated evaluation of post-therapeutic dysphagia considering relevant clinical features as well as the specific surgical therapy. From this assessment derives the indication of a safe pre-therapeutic application of a percutaneous endoscopic gastrostomy (PEG).


Subject(s)
Algorithms , Enteral Nutrition/methods , Gastrostomy/methods , Head and Neck Neoplasms/therapy , Intubation, Gastrointestinal/methods , Models, Biological , Adult , Aged , Aged, 80 and over , Case-Control Studies , Enteral Nutrition/adverse effects , Female , Gastrostomy/adverse effects , Humans , Intubation, Gastrointestinal/adverse effects , Male , Malnutrition/prevention & control , Middle Aged , Nutritional Status , Retrospective Studies , Risk Assessment/methods , Risk Factors , Young Adult
5.
Int J Oral Maxillofac Surg ; 40(7): 690-6, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21411291

ABSTRACT

Orthognathic surgery is associated with side effects including severe postoperative swelling, pain, neurological dysfunction and trismus. The beneficial effects of localised cold treatment on postoperative swelling have been described. Topographical considerations make it difficult to quantify facial swelling. A new and promising method to measure facial swelling seems to be optical face scanning. This study aimed to evaluate the 3D optical scanner to measure soft tissue swelling following orthognathic surgery. Postoperative swelling was treated either with conventional cooling by cold packs or with the water-circulating cooling device Hilotherm Clinic. Secondary endpoints in each group included postoperative pain, neurological complaints, duration of hospital stay, trismus and patient satisfaction. The use of the cooling device by Hilotherm significantly reduced postoperative swelling, pain and hospital duration compared with conventional cooling. Postoperative trismus and satisfaction with the cooling method was significantly higher in the Hilotherm group compared with conventional cooling. No differences were observed concerning neurological score and outcome. In conclusion, 3D optical scanning is a simple and precise method of quantifying face swelling after orthognathic surgery. Hilotherm significantly reduces swelling and duration of hospital stay compared with conventional cooling.


Subject(s)
Cryotherapy/methods , Edema/diagnosis , Face , Imaging, Three-Dimensional/methods , Orthognathic Surgical Procedures/methods , Postoperative Complications/diagnosis , Adult , Chin/innervation , Cryotherapy/instrumentation , Edema/prevention & control , Female , Hospitalization , Humans , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/instrumentation , Length of Stay , Male , Optical Devices , Orbit/innervation , Pain Measurement , Pain, Postoperative/prevention & control , Patient Satisfaction , Photography/instrumentation , Pilot Projects , Postoperative Complications/prevention & control , Prognathism/surgery , Prospective Studies , Range of Motion, Articular/physiology , Retrognathia/surgery , Single-Blind Method , Touch/physiology , Treatment Outcome , Trismus/prevention & control
6.
Eur J Surg Oncol ; 32(9): 1006-14, 2006 Nov.
Article in English | MEDLINE | ID: mdl-16806795

ABSTRACT

AIMS: To describe options and indications for different surgical reconstruction techniques after resection of large skin tumours on the scalp taking into account an interdisciplinary approach of cranio-maxillofacial surgeon, dermatologist, and neurosurgeon, and to evaluate complications and postoperative outcome. PATIENTS AND METHODS: From a total of 39 patients with large skin tumour resections on the scalp and/or the forehead, treated between January 01, 1995 and June 30, 2005, a number of 42 surgical reconstructions were performed. The medical histories, the surgical treatment, postoperative complications, follow-up and outcome were evaluated. RESULTS: The excision defects measured 146 cm(2) (range: 80.6-546 cm(2)) on average. The most common methods for defect closure were multiple rotation-advancement flaps (n=19). Six patients were treated with split-thickness skin grafts after bone drilling for inducing granulation tissue to grow. Free latissimus dorsi muscle flaps were used in 8 patients and radial forearm flaps in 4 cases. Postoperative complications were rare. An algorithm for the surgical approach to large scalp defects was developed. CONCLUSION: For reconstruction of large defects on the scalp and forehead, various reliable methods may be used with regard to individual patient-specific parameters in cooperation with different medical specialties involved.


Subject(s)
Forehead/surgery , Plastic Surgery Procedures/methods , Scalp/surgery , Skin Neoplasms/surgery , Aged , Female , Forehead/pathology , Humans , Male , Middle Aged , Postoperative Complications , Retrospective Studies , Scalp/pathology , Skin Transplantation , Surgical Flaps , Treatment Outcome
7.
Int J Oral Maxillofac Surg ; 35(9): 796-9, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16687237

ABSTRACT

Heat or auto-cured acrylic resins are materials that are commonly used in splint construction. Newly developed light-cured resins hold promise in view of the altered characteristics of the material. The aim of this study was to evaluate how far light-curing resin-based splints can be used in orthognathic surgery. Over a period of 1 year, 141 orthognathic surgeries were planned and performed using randomly chosen light-cured splints versus auto-polymerized splints. The performance of splint fabrication, the model planning and the clinical use were assessed by different measurements. The dental technician, the orthodontist and the surgeon evaluated objective parameters (model damage, fabrication time, accuracy of registration, adjustment time) as well as subjective criteria (handling). This study revealed that the use of light-curing splints significantly improved the accuracy (97.7% versus 81.2% in the case of acrylic materials). Less time was needed for the fabrication and adjustment of the splint. There was concomitantly less model damage to be observed when light-curing resins were used (9.2% versus 83.5%) and subjective measurements revealed significantly better handling of light-curing resin-based splints. Light-curing resin splints used in orthognathic surgery seem to be advantageous.


Subject(s)
Acrylic Resins/chemistry , Occlusal Splints , Orthodontic Appliance Design/methods , Orthognathic Surgical Procedures , Osteotomy, Le Fort/instrumentation , Acrylic Resins/therapeutic use , Humans , Light , Surveys and Questionnaires
8.
Int J Oral Maxillofac Surg ; 35(9): 783-90, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16697141

ABSTRACT

Osseointegration of implants is crucial for the long-term success of oral implants. Mineralization of the bone's extracellular matrix as the ultimate step of a mature bone formation is closely related to implant osseointegration. Osteogenesis at oral implants is a complex process, driven by cellular and acellular phenomena. The biological process of the maintenance and emergence of minerals in the vicinity of oral implants is influenced to a great extent by biophysical parameters. Implant-related structural and functional factors, as well as patient-specific factors, govern the features of osteogenesis. To understand the influence of these factors in peri-implant bone mineralization, it is important to consider the basic biological processes. Biological and crystallographic investigations have to be applied to evaluate mineralization at implant surfaces at the different hierarchical levels of analysis. This review gives insight into the complex theme of mineral formation around implants. Special focus is given to new developments in implant design and loading protocols aimed at accelerating osseointegration of dental implants.


Subject(s)
Bone and Bones/physiology , Calcification, Physiologic/physiology , Dental Implantation, Endosseous , Dental Implants , Osseointegration/physiology , Bone and Bones/chemistry , Bone and Bones/ultrastructure , Humans , Surface Properties , Weight-Bearing
9.
J Eur Acad Dermatol Venereol ; 20(2): 190-6, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16441630

ABSTRACT

Surgery in malignant melanoma of the external ear often leads to substantial defects where reconstruction poses a difficult challenge. We describe an option of a one-step ear reconstruction after subtotal ear resection in malignant melanoma surgery. In a patient with a high-risk melanoma of the helical rim, a wide local excision was performed. Because of a metastasis-suspect lymph node in the parotid gland, surgery included asservation of the sentinel lymph node, neck dissection and parotidectomy. A complete reconstruction of the ear was achieved using a bilobed flap from the retroauricular and neck region with acceptable cosmetic and functional results by one-step surgery. One micrometastasis was detected in the nuchal region but not in the marked sentinel lymph node. An adequate one-step ear reconstruction as described may also be performed to the benefit of patients with high-risk melanomas, allowing early adjuvant therapy.


Subject(s)
Melanoma/diagnosis , Skin Neoplasms/diagnosis , Adult , Diagnosis, Differential , Ear, External/pathology , Ear, External/surgery , Humans , Lymphatic Metastasis , Male , Melanoma/secondary , Melanoma/surgery , Neoplasm Metastasis , Parotid Gland/surgery , Plastic Surgery Procedures , Skin Neoplasms/pathology , Skin Neoplasms/surgery
10.
Mund Kiefer Gesichtschir ; 9(6): 349-62, 2005 Nov.
Article in German | MEDLINE | ID: mdl-16142459

ABSTRACT

BACKGROUND: Aggressive fibromatosis (AF) involving bones of the head is rare and surgery is often complicated by a high recurrence rate. Interdisciplinary treatment is of the utmost importance to avoid extensive, mutilating resection. Two cases emphasize the difficulties in the management. CASE REPORTS: A 67-year-old woman was referred to our unit with a blepharochalasis of the left upper palpebra and a palsy of the face on the left side. Her medical history included 12 operations over the previous 4 years for an extensive AF. MATERIAL AND METHODS: Our review includes all case reports of AF involving bones of the head published between 1960 and 2004. Additionally, our two cases are presented. Signs, symptoms and outcome were analyzed in relation to different treatment options. CONCLUSION: According to the literature, surgery is the most common treatment for AF in the head and neck region. Alternative modes of therapy must be considered because of the high recurrence rate and to avoid mutilating operations.


Subject(s)
Eyelid Neoplasms/diagnosis , Facial Neoplasms/diagnosis , Fibromatosis, Aggressive/diagnosis , Fibromatosis, Gingival/diagnosis , Jaw Neoplasms/diagnosis , Skull Neoplasms/diagnosis , Aged , Eyelid Neoplasms/surgery , Facial Neoplasms/surgery , Female , Fibromatosis, Aggressive/surgery , Fibromatosis, Gingival/surgery , Humans , Jaw Neoplasms/surgery , Neoplasm Recurrence, Local/diagnosis , Neoplasm Recurrence, Local/surgery , Patient Care Team , Radiography, Panoramic , Reoperation , Skull Neoplasms/surgery , Surgery, Plastic
11.
Int J Oral Maxillofac Surg ; 34(8): 907-11, 2005 Dec.
Article in English | MEDLINE | ID: mdl-15916880

ABSTRACT

Reduction of the expression of catenin is a crucial step in the pathogenesis, progression and prognosis of many epithelial cancers including squamous cell carcinomas (SCCs). Catenin expression in oral carcinomas was evaluated in relation to clinico-pathological features in order to determine its value as a prognostic marker. Eighty-five patients with histologically proven T1/2 squamous cell carcinoma of the oral floor who underwent surgical treatment were eligible for the study. A tissue microarray consisting of multiple representative tissue cores of each carcinoma was composed. The expression levels of alpha, beta and gamma-catenins were determined immunohistologically. Correlation between clinical features and the expression of catenin proteins was evaluated statistically using Kaplan-Meier curves, log-rank tests and chi(2)-tests. Loss of alpha-catenin expression in carcinoma of the floor of the mouth correlated significantly with poor prognosis (P=0.05). Conversely, significantly reduced rates of lymph-node metastases were observed in alpha- and beta-catenin-positive T1 and T2 SCCs. Loss of gamma-catenin expression indicated a reduced survival rate in nodal-negative tumours (P=0.02). Catenin expression in carcinomas of the floor of the mouth seems to be a predictive parameter in the prognosis of T1 and T2 SSCs.


Subject(s)
Biomarkers, Tumor/biosynthesis , Carcinoma, Squamous Cell/metabolism , Catenins/biosynthesis , Mouth Floor/pathology , Mouth Neoplasms/metabolism , Adult , Aged , Aged, 80 and over , Carcinoma, Squamous Cell/chemistry , Carcinoma, Squamous Cell/pathology , Female , Humans , Kaplan-Meier Estimate , Lymphatic Metastasis , Male , Middle Aged , Mouth Neoplasms/chemistry , Mouth Neoplasms/pathology , Prognosis , Proportional Hazards Models , Tissue Array Analysis
12.
Eur Cell Mater ; 9: 39-49, 2005 Apr 26.
Article in English | MEDLINE | ID: mdl-15852237

ABSTRACT

In order to assess how bone substitute materials determine bone formation in vivo it is useful to understand the mechanisms of the material surface/tissue interaction on a cellular level. Artificial materials are used in two applications, as biomaterials alone or as a scaffold for osteoblasts in a tissue engineering approach. Recently, many efforts have been undertaken to improve bone regeneration by the use of structured material surfaces. In vitro studies of bone cell responses to artificial materials are the basic tool to determine these interactions. Surface properties of materials surfaces as well as biophysical constraints at the biomaterial surface are of major importance since these features will direct the cell responses. Studies on osteoblastlike cell reactivity towards materials will have to focus on the different steps of protein and cell reactions towards defined surface properties. The introduction of new techniques allows nowadays the fabrication of materials with ordered surface structures. This paper gives a review of present knowledge on the various stages of osteoblast reactions on material surfaces, focused on basic cell events under in vitro conditions. Special emphasis is given to cellular reactions towards ordered nano-sized topographies.


Subject(s)
Biocompatible Materials/chemistry , Biocompatible Materials/metabolism , Osteoblasts/metabolism , Cell Physiological Phenomena , Collagen/ultrastructure , Humans , Osteoblasts/ultrastructure , Surface Properties , Titanium
13.
Acta Anaesthesiol Scand ; 49(5): 654-9, 2005 May.
Article in English | MEDLINE | ID: mdl-15836679

ABSTRACT

BACKGROUND: This study was designed to evaluate prognostic parameters for respiratory failure after major oropharyngeal resections in head and neck cancer surgery, focusing on a score system to identify patients requiring an elective tracheotomy and to avoid tracheotomy under emergency conditions. METHODS: One hundred and fifty-two out of 928 patients with oropharyngeal cancers, treated between January 1993 and June 2000 at our hospital, fulfilled the inclusion criteria for a retrospective analysis. This collective underwent tumour resection in different regions of the oropharynx combined with bony resection of the mandible and neck dissection without primary tracheotomy. The reconstruction was accomplished using radial forearm flaps (n1 = 59) or local flaps (n2 = 93). These two groups were subdivided into patients treated post-operatively by tracheotomy due to respiratory failure (n1 = 26; n2 = 12) and those without such treatment (n1 = 33; n2 = 81). The database comprising tumour localization and size, staging, general medical condition, smoking and alcohol consumption was evaluated by logistic regression. RESULTS: We developed a score system which predicts the likelihood of post-operative respiratory failure. For indication of tracheotomy, tumour size and localization, multimorbidity, alcohol consumption and pathologic chest X-ray findings were identified as significant parameters with different weightings. The predictive value for tracheotomy (yes/no) using the score system was 96.7% for the total collective. CONCLUSION: The decision on whether or not an elective tracheotomy in major head and neck tumour surgery is necessary can be facilitated using this score system which is based on objective facts. It may reduce post-operative complications and contribute to safer treatment.


Subject(s)
Head and Neck Neoplasms/surgery , Intraoperative Complications/epidemiology , Intraoperative Complications/surgery , Respiratory Insufficiency/epidemiology , Respiratory Insufficiency/surgery , Tracheotomy , Adult , Aged , Aged, 80 and over , Alcohol Drinking , Elective Surgical Procedures , Female , Head and Neck Neoplasms/diagnostic imaging , Humans , Logistic Models , Male , Middle Aged , Neoplasm Staging , Oropharyngeal Neoplasms/surgery , Oropharynx/surgery , Prognosis , Radiography , Retrospective Studies , Risk Assessment
14.
Mund Kiefer Gesichtschir ; 9(1): 24-8, 2005 Jan.
Article in German | MEDLINE | ID: mdl-15583966

ABSTRACT

The osseointegration process of dental implants depends on the tissue reaction at the tissue-implant interface. Osteoblasts are the main cells responsible for the regulation of osteoinduction. The manner and kinetics of the tissue reaction crucially depend on the interaction between osteoblasts and the morphology of the implant surface. The aim of this study was to investigate osteoblast behaviour on different implant surfaces (smooth, microgrooved, SLA) under standardized conditions. For this in vitro investigation we used primary bovine osteoblasts. Attachment kinetics, proliferation rate and synthesis of bone-associated proteins were used as parameters for cell reaction. The results demonstrate that both attachment and adhesion strength of the primary cell surface interaction was higher on the microgrooved surfaces than on SLA surfaces. The proliferation rate of cells and the synthesis of bone-specific proteins were higher on microgrooved surfaces in contrast to SLA surfaces. Ultrastructural analysis revealed phenotypic osteoblast-like cells on smooth and microgrooved surfaces, whereas cells on SLA surfaces showed a more fibroblastic appearance. This study demonstrates that the morphology of the implant surface determined the subsequent osteoblast reaction. An optimal cell reaction was found at surfaces which are smooth in the microenvironment of osteoblasts.


Subject(s)
Cell Division/physiology , Coated Materials, Biocompatible , Dental Implants , Osseointegration/physiology , Osteoblasts/physiology , Titanium/pharmacology , Animals , Cattle , Cell Adhesion/physiology , Cell Count , Cell Differentiation/physiology , Humans , Microscopy, Electron, Scanning , Osteoblasts/diagnostic imaging , Osteocalcin/metabolism , Osteonectin/metabolism , Surface Properties , Ultrasonography
15.
Mund Kiefer Gesichtschir ; 8(5): 282-8, 2004 Sep.
Article in German | MEDLINE | ID: mdl-15480869

ABSTRACT

BACKGROUND: The treatment of patients with early or immediately loaded dental implants has renewed interest in the behavior of osseointegration at the implant surface. Whereas it is generally accepted that peri-implant tissue formation and mineralization are dependent on the local mechanical environment in the interface zone, controversies exist concerning the impact of implant design on peri-implant bone formation. The aim of the present study was the in vivo evaluation of peri-implant bone formation by two different implant systems: cylindrical (ITI) versus conical (ILI). MATERIAL AND METHOD: A total of 60 implants (30 ITI and 30 ILI) were placed in the cranial and caudal part of the tibia of eight Göttinger minipigs. Half of the minipigs were sacrificed at 7 days and 28 days of osseointegration. Implant-containing bone specimens were prepared for histological and ultrastructural investigations. RESULTS: Histological and scanning electron-microscopic investigations showed a direct contact of bone-like minerals over the whole implant surface from day 7 of implant/bone interaction. Whereas the ILI implant showed direct contact up to the top of the crestal bone, ITI implants demonstrated a crestally located narrow gap without ossification over the whole experimental period. CONCLUSION: Our investigations support the hypothesis of an implant design-inherent emergence and maintenance of crestal bone.


Subject(s)
Dental Implantation, Endosseous , Osseointegration/physiology , Animals , Dental Prosthesis Design , Finite Element Analysis , Male , Microscopy, Electron, Scanning , Swine , Swine, Miniature , Tibia/pathology , Tibia/surgery , Wound Healing/physiology
16.
Int J Oral Maxillofac Surg ; 33(7): 635-41, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15337175

ABSTRACT

Over the last decade extracorporal bone tissue engineering has moved from laboratory to clinical application. The restoration of maxillofacial bones from cell harvesting through product manufacture and end-use has benefited from innovations in the fields of biomechanical engineering, product marketing and transplant research. Cell/scaffold bone substitutes face a variety of unique clinical challenges which must be addressed. This overview summarises the recent state of the art and future anticipations in the transplantation of extracorporally fabricated bone tissues.


Subject(s)
Bone and Bones/cytology , Tissue Engineering , Animals , Biomechanical Phenomena , Bone Transplantation/methods , Bone and Bones/immunology , Cell Culture Techniques , Graft Rejection , Humans , Osteoblasts/immunology , Osteoblasts/transplantation , Stem Cell Transplantation
17.
Int J Oral Maxillofac Surg ; 33(6): 523-30, 2004 Sep.
Article in English | MEDLINE | ID: mdl-15308249

ABSTRACT

The aim of this review is to characterise the biological and biophysical background of in vitro bone tissue engineering. The paper focuses on basic principles in extracorporal engineering of bone-like tissues, considering parameters such as scaffold design, tissue construction, bioreactors, and cell stimulation in vivo and in vitro. Scaffolds have a key function concerning cellular invasion and bone formation. The intra-architectural scaffold geometry, as well as the scaffold material, play an important role in the process of bone regeneration. Various types of bioreactors have been tested for their utility in bone substitute fabrication that is clinically effective and reproducible. Sophisticated bioreactor systems are those that mimic the three-dimensional morphology and the mechanical situation of bones. Mechanical stimulation as well as other biophysical stimuli appear to be critical factors for proliferation and differentiation of bone cells and for bone mineral and structure formation. Furthermore an enhancement of bone regeneration by application of chemical stimulation factors is discussed.


Subject(s)
Bone Regeneration , Bone and Bones/cytology , Culture Techniques/methods , Tissue Engineering/methods , Animals , Biocompatible Materials , Bone Regeneration/drug effects , Bone Regeneration/physiology , Bone and Bones/drug effects , Dental Stress Analysis , Growth Substances/pharmacology , Humans , Stress, Mechanical
18.
Int J Oral Maxillofac Surg ; 33(4): 325-32, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15145032

ABSTRACT

Advances in the field of bone tissue engineering have encouraged physicians to introduce these techniques into clinical practice. Bone tissue engineering is the construction, repair or replacement of damaged or missing bone in humans or animals. Engineering of bone can take place within the animal body or extracorporal in a bioreactor for later grafting into the body. Appropriate cell types and non-living substrata are minimal requirements for an extracorporal tissue engineering approach. This review discusses the biological and biophysical background of in vitro bone tissue engineering. Biochemical and biophysical stimuli of cell growth and differentiation are regarded as potent tools to improve bone formation in vitro. The paper focuses on basic principles in extracorporal engineering of bone-like tissues, intended to be implanted in animal experiments and clinical studies. Particular attention is given in this part to the contributions of cell and material science to the development of bone-like tissues. Several approaches are at the level of clinical applicability and it can be expected that widespread use of engineered bone constructs will change the surgeon's work in the near future.


Subject(s)
Bone and Bones/cytology , Tissue Engineering , Animals , Calcification, Physiologic , Cell Culture Techniques , Extracellular Matrix , Humans , Osteoblasts , Stem Cells
19.
Biomaterials ; 25(10): 1959-67, 2004 May.
Article in English | MEDLINE | ID: mdl-14738860

ABSTRACT

Primary stability and an optimized load transfer are assumed to account for an undisturbed osseointegration process of implants. Immediate loaded newly designed titanium dental implants inserted in the mandible of minipigs were used for the characterization of the interfacial area between the implant surface and the surrounding bone tissue during the early healing phase. Histological and electron microscopical studies were performed from implant containing bone specimens. Two different load regimens were applied to investigate the load related tissue reaction. Histological and electron microscopical analysis revealed a direct bone apposition on the implant surfaces, as well as the attachment of cells and matrix proteins in the early loading phase. A striking finding of the ultrastructural immunocytochemical investigations was the synthesis and deposition of bone related proteins (osteonectin, fibronectin, fibronectin receptor) by osteoblasts from day one of bone/biomaterial interaction. Calcium-phosphate needle-like crystallites were newly synthesized in a time-related manner directly at the titanium surface. No difference in the ultrastructural appearance of the interface was found between the two loading groups. Our experimental data suggest that loading of specially designed implants can be performed immediately after insertion without disturbing the biological osseointegration process.


Subject(s)
Dental Implantation/methods , Dental Implants , Mandible/physiology , Mandible/ultrastructure , Osseointegration/physiology , Weight-Bearing/physiology , Animals , Bone Screws , Equipment Failure Analysis , Fibronectins/metabolism , Integrin alpha5beta1/metabolism , Male , Mandible/cytology , Mandible/surgery , Osteonectin/metabolism , Surface Properties , Swine , Swine, Miniature
20.
Int J Oral Maxillofac Surg ; 33(1): 19-24, 2004 Jan.
Article in English | MEDLINE | ID: mdl-14690655

ABSTRACT

The diagnostic records of all patients who had undergone Delaire/Joos osteotomy with mandibular setback at the Muenster University Hospital (period 1995-2000, n=22) were used for space management evaluation in the context of combined surgical-orthodontic treatment.Twenty-eight dental spaces were present prior to the start of treatment and 14 were created by extracting teeth as a pretreatment measure. In two patients, unilateral setback was performed according to Obwegeser/Dal Pont. Thus, 42 tooth-bounded spaces were present at the time of Delaire/Joos osteotomy with mandibular setback, most of them in the first molar region, followed by the second premolar region. A significant space reduction was achieved by the surgical intervention, but not by the subsequent orthodontic treatment. The best results with respect to complete space closure by orthognathic surgery/orthodontic treatment without the need for subsequent prosthetic rehabilitation were recorded in the second premolar region. In the absence of spaces and with a similar long-term prognosis for all potentially extractable teeth and adequate space for the necessary surgical repositioning, the second premolars should therefore be regarded as the 'extraction teeth of choice' for mandibular setback within the context of Delaire/Joos osteotomy.


Subject(s)
Malocclusion/surgery , Malocclusion/therapy , Mandible/surgery , Oral Surgical Procedures , Orthodontic Space Closure , Adolescent , Adult , Female , Humans , Longitudinal Studies , Male , Osteotomy/methods , Prognathism/surgery , Retrospective Studies , Tooth Extraction
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