Population-Based Design of Mandibular Fixation Plates with Bone Quality and Morphology Considerations

In this paper we present a new population-based implant design methodology, which advances the state-of-the-art approaches by combining shape and bone quality information into the design strategy. The method may enhance the mechanical stability of the fixation and reduces the intra-operative in-plane bending which might impede the functionality of the locking mechanism. The computational method is presented for the case of mandibular locking fixation plates, where the mandibular angle and the bone quality at screw locations are taken into account. The method automatically derives the mandibular angle and the bone thickness and intensity values at the path of every screw from a set of computed tomography images. An optimization strategy is then used to optimize the two parameters of plate angle and screw position. The method was applied to two populations of different genders. Results for the new design are presented along with a comparison with a commercially available mandibular locking fixation plate (MODUS® TriLock® 2.0/2.3/2.5, Medartis AG, Basel, Switzerland). The proposed designs resulted in a statistically significant improvement in the available bone thickness when compared to the standard plate. There is a higher probability that the proposed implants cover areas of thicker cortical bone without compromising the bone mineral density around the screws. The obtained results allowed us to conclude that an angle and screw separation of 129° and 9mm for females and 121° and 10mm for males are more suitable designs than the commercially available 120° and 9m

Osteoblast proliferation and differentiation on a barrier membrane in combination with BMP2 and TGFβ1

Objectives: Bioresorbable collagen membranes are routinely utilized in guided bone regeneration to selectively direct the growth and repopulation of bone cells in areas of insufficient volume. However, the exact nature by which alveolar osteoblasts react to barrier membranes as well as the effects following the addition of growth factors to the membranes are still poorly understood. The objective of the present study was therefore to investigate the effect of a bioresorbable collagen membrane soak-loaded in growth factors bone morphogenetic protein 2 (BMP2) or transforming growth factor β1 (TGFβ1) on osteoblast adhesion, proliferation, and differentiation. Material and methods: Prior to experimental seeding, membranes were soaked in either BMP2 or TGFβ1 at a concentration of 10ng/ml for 5min. Results: Human osteoblasts adhered to all soak-loaded membranes as assessed by scanning electron microscopy. Growth factors BMP2 and TGFβ1 increased osteoblast proliferation at 3 or 5days post-seeding when compared to control collagen membranes. Analysis of real-time PCR revealed that administration of BMP2 increased osteoblast differentiation markers such as osterix, collagen I, and osteocalcin. BMP2 also increased mineralization of primary osteoblasts as demonstrated by alizarin red staining when compared to control and TGFβ1 soak-loaded membranes. Conclusion: The combination of a collagen barrier membrane with growth factors TGFβ1 and BMP2 significantly influenced adhesion, proliferation, and differentiation of primary human osteoblasts. Clinical relevance: The described in vitro effects following the combination of collagen barrier membranes with growth factors TGFβ1 and BMP2 provide further biologic support for the clinical application of this treatment strategy in guided bone regeneration procedure

Neurolytic effects of ampicillin on the rat infraorbital nerve

PURPOSE: The aim of this study was to investigate the histomorphological changes of the infraorbital nerve of rats treated with ampicillin. MATERIALS AND METHODS: The infraorbital nerve was approached through the infraorbital foramen, and 0.01 ml of ampicillin dissolved in distilled water was injected taking care not to damage the nerve. Saline solution was used in control animals. Nerves were dissected and after routine histology processing analysed by light microscopy. RESULTS: Cross-section of the nerve treated with ampicillin showed damaged axons with disintegration of heavily myelinated fibres, while thinly myelinated fibres remain unaffected. In the saline group, no damage was observed. The signs of regeneration of the damaged infraorbital nerves were detected on the fourth postoperative week. CONCLUSION: Ampicillin can cause peripheral nerve damage when injected perineurally. J Oral Pathol Med (2012) 41: 268-27

A rare low-grade myofibroblastic sarcoma in lower jaw with the resemblance to benign lesions.

BACKGROUND Low-grade myofibroblastic sarcoma (LGMS) is a rare solid infiltrative soft tissue tumor with a predilection for the head and neck region. CASE PRESENTATION We report the diagnostic steps of a fast-growing lesion of the lower left jaw in a 45-year-old otherwise healthy woman. A first biopsy and subsequent histopathological examination showed potential differentials of a benign myofibroma, benign nodular fasciitis or an LGMS. This diagnostic overlap was a challenge for the decision of the further treatment approach. The treatment consisted of a segmental en bloc resection of the mandible including the second premolar, first and second molar. Histopathological examination of the resected tumor confirmed an LGMS. CONCLUSION The histopathologic resemblance of LGMS to a range of benign and reactive tumors may lead to misdiagnosis and mistreatment. The rarity of LGMS explains the lack of established treatment protocols. This case shows the importance of adequate clinical decisions, expertise in the histopathology of rare tumors and interdisciplinary exchange to achieve state-of-the-art patient management

Incidence, aetiology and pattern of mandibular fractures in central Switzerland

The two major causative factors for mandibular fractures, as stated in the literature, are either interpersonal violence or motor vehicle accidents. The purpose of this study was to describe epidemiological trends of mandibular fractures in Switzerland. A special emphasis was directed towards the potential impact of socio-economic standards on the mechanism and pattern of mandible fractures

Single-visit chairside adjustment of a metal-acrylic resin implant-supported fixed complete dental prosthesis on an unloaded implant using a novel fixed attachment system: a case report

Background: Implant-supported prosthetic treatment options are reliable for elderly edentulous patients with systemic health problems. These patients often need cost- and time-efficient solutions to avoid complications. However, it is a challenge for clinicians to treat these patients without surgical interventions, placement of additional implants, or the need to renew existing prostheses. Case presentation: A 75-year-old medically compromised caucasian male patient using multiple medications was referred for prosthetic rehabilitation of his edentulous maxilla after several implant failures. Because the patient's health was compromised, further surgical interventions were ruled out and the treatment was centered on the use of the remaining implants by placing a fixed attachment system and altering the existing prosthesis. The stepwise management of the patient's situation through the use of a new attachment system and adjustment of existing prosthesis is described in the present case report. Conclusions: Although implant therapy is not always contraindicated for medically compromised patients, it is preferable not to perform extensive surgeries to avoid complications. This clinical report describes an alternative, safe option based on a novel fixed attachment system to salvage an existing maxillary implant-supported fixed complete dental prosthesis of a patient with systemic health problems

Premature Osteoblast Clustering by Enamel Matrix Proteins Induces Osteoblast Differentiation through Up-Regulation of Connexin 43 and N-Cadherin

In recent years, enamel matrix derivative (EMD) has garnered much interest in the dental field for its apparent bioactivity that stimulates regeneration of periodontal tissues including periodontal ligament, cementum and alveolar bone. Despite its widespread use, the underlying cellular mechanisms remain unclear and an understanding of its biological interactions could identify new strategies for tissue engineering. Previous in vitro research has demonstrated that EMD promotes premature osteoblast clustering at early time points. The aim of the present study was to evaluate the influence of cell clustering on vital osteoblast cell-cell communication and adhesion molecules, connexin 43 (cx43) and N-cadherin (N-cad) as assessed by immunofluorescence imaging, real-time PCR and Western blot analysis. In addition, differentiation markers of osteoblasts were quantified using alkaline phosphatase, osteocalcin and von Kossa staining. EMD significantly increased the expression of connexin 43 and N-cadherin at early time points ranging from 2 to 5 days. Protein expression was localized to cell membranes when compared to control groups. Alkaline phosphatase activity was also significantly increased on EMD-coated samples at 3, 5 and 7 days post seeding. Interestingly, higher activity was localized to cell cluster regions. There was a 3 fold increase in osteocalcin and bone sialoprotein mRNA levels for osteoblasts cultured on EMD-coated culture dishes. Moreover, EMD significantly increased extracellular mineral deposition in cell clusters as assessed through von Kossa staining at 5, 7, 10 and 14 days post seeding. We conclude that EMD up-regulates the expression of vital osteoblast cell-cell communication and adhesion molecules, which enhances the differentiation and mineralization activity of osteoblasts. These findings provide further support for the clinical evidence that EMD increases the speed and quality of new bone formation in vivo