Ole Jung

Impact of Dental Implant Surface Modifications on Osseointegration.

Objective. The aim of this paper is to review different surface modifications of dental implants and their effect on osseointegration. Common marketed as well as experimental surface modifications are discussed. Discussion. The major challenge for contemporary dental implantologists is to provide oral rehabilitation to patients with healthy bone conditions asking for rapid loading protocols or to patients with quantitatively or qualitatively compromised bone. These charging conditions require advances in implant surface design. The elucidation of bone healing physiology has driven investigators to engineer implant surfaces that closely mimic natural bone characteristics. This paper provides a comprehensive overview of surface modifications that beneficially alter the topography, hydrophilicity, and outer coating of dental implants in order to enhance osseointegration in healthy as well as in compromised bone. In the first part, this paper discusses dental implants that have been successfully used for a number of years focusing on sandblasting, acid-etching, and hydrophilic surface textures. Hereafter, new techniques like Discrete Crystalline Deposition, laser ablation, and surface coatings with proteins, drugs, or growth factors are presented. Conclusion. Major advancements have been made in developing novel surfaces of dental implants. These innovations set the stage for rehabilitating patients with high success and predictable survival rates even in challenging conditions.

Definition, etiology, prevention and treatment of peri-implantitis – a review

Peri-implant inflammations represent serious diseases after dental implant treatment, which affect both the surrounding hard and soft tissue. Due to prevalence rates up to 56%, peri-implantitis can lead to the loss of the implant without multilateral prevention and therapy concepts. Specific continuous check-ups with evaluation and elimination of risk factors (e.g. smoking, systemic diseases and periodontitis) are effective precautions. In addition to aspects of osseointegration, type and structure of the implant surface are of importance. For the treatment of peri-implant disease various conservative and surgical approaches are available. Mucositis and moderate forms of peri-implantitis can obviously be treated effectively using conservative methods. These include the utilization of different manual ablations, laser-supported systems as well as photodynamic therapy, which may be extended by local or systemic antibiotics. It is possible to regain osseointegration. In cases with advanced peri-implantitis surgical therapies are more effective than conservative approaches. Depending on the configuration of the defects, resective surgery can be carried out for elimination of peri-implant lesions, whereas regenerative therapies may be applicable for defect filling. The cumulative interceptive supportive therapy (CIST) protocol serves as guidance for the treatment of the peri-implantitis. The aim of this review is to provide an overview about current data and to give advices regarding diagnosis, prevention and treatment of peri-implant disease for practitioners.

Optimized in vitro procedure for assessing the cytocompatibility of magnesium-based biomaterials.

Magnesium (Mg) is a promising biomaterial for degradable implant applications that has been extensively studied in vitro and in vivo in recent years. In this study, we developed a procedure that allows an optimized and uniform in vitro assessment of the cytocompatibility of Mg-based materials while respecting the standard protocol DIN EN ISO 10993-5:2009. The mouse fibroblast line L-929 was chosen as the preferred assay cell line and MEM supplemented with 10% FCS, penicillin/streptomycin and 4mM l-glutamine as the favored assay medium. The procedure consists of (1) an indirect assessment of effects of soluble Mg corrosion products in material extracts and (2) a direct assessment of the surface compatibility in terms of cell attachment and cytotoxicity originating from active corrosion processes. The indirect assessment allows the quantification of cell-proliferation (BrdU-assay), viability (XTT-assay) as well as cytotoxicity (LDH-assay) of the mouse fibroblasts incubated with material extracts. Direct assessment visualizes cells attached to the test materials by means of live-dead staining. The colorimetric assays and the visual evaluation complement each other and the combination of both provides an optimized and simple procedure for assessing the cytocompatibility of Mg-based biomaterials in vitro.

Applications of Metals for Bone Regeneration

The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, as well as resorb in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated, where it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between new bone tissue formation and material degradation has not been found, until now. The addition of different substances such as collagen or growth factors and also of different cell types has already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are used differently as a basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue, playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designed for bone regeneration, with the aim to provide an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.

From bench to application: Current practices in tissue engineering and its realisation at maxillofacial units in Germany, Austria and Switzerland

Over the last 20 years, the highly interdisciplinary field of tissue engineering (TE) has become an established subspecialty in research facilities all over the world. Numerous methods and protocols are available for various research intentions and aims, but there are no data indicating which of these methods and resources are generally used. This study is an overview of the resources and methods that are commonly applied in TE research in general, and in the field of oral and maxillofacial surgery (OMFS) in Germany, Austria and Switzerland. The DÖSAK collaborative group for TE developed a detailed questionnaire and collected information from participating university hospitals in these three countries. We evaluated the availability of research facilities, in vitro realisation and in vivo designs for animal studies in these departments. 11 units who replied, out of 35 we contacted, conducted research on bone regeneration in interdisciplinary research facilities. 10 departments used xenogeneic and alloplastic scaffolds for in vitro and in vivo applications. In this case, the most commonly utilised trademarks were Bio-Oss(®) and CERASORB(®). 9 units used osteoblasts (73%) and 10 proliferation assays in vitro, whereas rats served as the standard animal model for histology/immunohistochemistry in 6. All research units were interested in establishing a platform for research exchange and communication. This study shows that tissue engineering is well established and highly accepted in most participating university hospitals and research facilities. The presented data, together with data published in a foregoing paper will help arrange more readily available standardised procedures for further investigations.

Purification processes of xenogeneic bone substitutes and their impact on tissue reactions and regeneration

Xenogeneic bone substitute materials are widely used in oral implantology. Prior to their clinical use, purification of the former bone tissue has to be conducted to ensure the removal of immunogenic components and pathogens. Different physicochemical methods are applied for purification of the donor tissue, and temperature treatment is one of these methods. Differences in these methods and especially the application of different temperatures for purification may lead to different material characteristics, which may influence the tissue reactions to these materials and the related (bone) healing process. However, little is known about the different material characteristics and their influences on the healing process. Thus, the aim of this mini-review is to summarize the preparation processes and the related material characteristics, safety aspects, tissue reactions, resorbability and preclinical and clinical data of two widely used xenogeneic bone substitutes that mainly differ in the temperature treatment: sintered (cerabone®) and non-sintered (Bio-Oss®) bovine-bone materials. Based on the summarized data from the literature, a connection between the material-induced tissue reactions and the consequences for the healing processes are presented with the aim of translation into their clinical application.

A patient with Charlie M Syndrome: Differential diagnosis of Oromandibular Limb Hypogenesis Syndromes.

AIM In order to provide adequate treatment to a patient with a subtype of Oromandibular Limb Hypogenesis Syndromes (OLHS), this study aimed to review and to analyze the current literature and treatment options of OLHS. METHODS Literature review in PubMed and Sciencedirect. Due to the small number of results, all available references were analyzed precisely. RESULTS Cases of OLHS are formerly rare and often incomplete. There are various classifications available, which, however, often seem confusing and are of little practical relevance. Furthermore, we present a complete case report of a patient with Charlie M syndrome, a type IV (Chicarilli)/ V (Hall) OLHS malformation. We also describe embryologic pathogenesis and differential diagnoses. CONCLUSION As a result of our literature review, we recommend an adjusted classification for OLHS.

Future Perspectives of Bisphosphonates in Maxillofacial, Dental, and Medical Practice

Today, bisphosphonates are already used in a variety of indications, which by far exceed the commonly known applications. Closely related to their anorganic compound pyrophosphate, organic bisphosphonates are already used in everyday products like toothpastes and reagents for anticalculus and anti-calcification purposes. Besides that, bisphosphonates were successfully applied within experimental, animal, and clinical trial studies for dental socket preservations, periodontitis, and periimplantitis. Thereby, among other positive aspects like distinctive antibacterial profiles, more bone formation and fewer bone resorption were detected. Several other conditions commonly seen in oral and maxillofacial surgery might also benefit from administrations of antiresorptive drugs. In addition, bisphosphonates can also be successfully administered in uranyl intoxications as well as for hard and soft tissue calcifications. The primary aim of the ongoing research in this field can be defined in the detection of the ideal dose-effect relationship of different bisphosphonates when applied intravenously, orally, or topically.

Treatment of a bilaterally severely resorbed posterior mandible due to early tooth loss by Guided Bone Regeneration using customized allogeneic bone blocks: A case report with 24 months follow-up data

OBJECTIVE The use of allogeneic bone grafts for alveolar ridge reconstruction has become an often-discussed alternative to augmentation procedures using autografts. Nevertheless, there still is a lack of literature concerning long-time experiences of allografts for alveolar ridge reconstruction. Especially the results of the use of allogeneic bone blocks for mandible reconstructions need to be further investigated. CLINICAL CONSIDERATIONS In this case report, we present the use of customized allogenic bone blocks in Guided Bone Regeneration (GBR) procedures for severely deficient mandibulary bones, the implantation after a healing period of 5 month and the 24-month follow-up data. CONCLUSIONS Customized allogeneic bone blocks seem to be a successful alternative to augmentations with autologous bone blocks reconstructing highly resorbed mandibulary alveolar ridges, showing highest volume stability and no signs of bone resorption after implant loading. CLINICAL SIGNIFICANCE The application of customized allogeneic bone blocks has shown to be a successful augmentation technique even compared with with autologous bone blocks reconstructing highly resorbed mandibulary alveolar ridges demonstrating no compromises regarding clinical outcome, functionality and esthetics.

Vertical bone augmentation in a single-tooth gap with an allogenic bone ring: Clinical considerations

OBJECTIVE The main objective of this case report is to introduce a one-stage bone block augmentation with a cylindrical freeze-dried bone allograft (FDBA) and simultaneous implantation for the reconstruction of a single-tooth bone defect. CLINICAL CONSIDERATIONS The report describes this method on the basis of radiographical and clinical images derived from a single patient. CONCLUSIONS The report demonstrates the time-saving and successful application of this treatment concept, which has the potential to increase patient satisfaction and comfort. CLINICAL SIGNIFICANCE The application of the presented technique enabled a prosthetic rehabilitation of the extracted tooth about 3 months earlier as compared to the conventional procedure, while demonstrating no compromises regarding clinical outcome, functionality and esthetics.