Ingo N. Springer

Bis-phossy jaws - high and low risk factors for bisphosphonate-induced osteonecrosis of the jaw.

INTRODUCTION Bisphosphonates (BPs) have transformed our ability to treat certain malignancies, osteoporosis and hypercalcaemia. This class of drug is assumed to be well tolerated by most. There are some important caveats to this assumption, however, one of the significances being the risk of osteonecrosis of the jaw (ONJ). MATERIAL AND METHODS This multi-centre retrospective study examined the role of different BPs on the development of ONJ, its clinical presentation and the efficacy of various treatment modalities, comparing these findings with the available literature. RESULTS A total of 78 patients from 17 centres were identified with ONJ. A majority of patients identified with ONJ had used Pamidronate or Zoledronate (93.6%) intravenously. 94.9% of patients had received BP in the course of treatment for malignancies and a majority had also received prior chemotherapy or exogenous steroids. 82.1% of patients had received BP for more than 1 year. The mean time from the introduction of BP to the development of ONJ in 24 patients from our department was 31.8 months. CONCLUSIONS The most common intraoral manifestation was exposed necrotic jawbone. Tooth extractions and oral surgical intervention appear to place patients on BP therapy at risk of ONJ, especially after intravenous BP treatments. ONJ proved in this study to be remarkably refractory to treatment, with radical resection being the only curative approach. We recommend that all patients receive necessary dental treatment prior to commencing BP therapy.

Prospective observation of 41 perforations of the Schneiderian membrane during sinus floor elevation

OBJECTIVES The aim of this study was to follow 41 intraoperative perforations of the Schneiderian membrane during sinus floor elevation and to identify potential differences from patients without perforations. MATERIAL AND METHODS Two hundred and one sinus floor elevations were performed at the department of oral and maxillofacial surgery of the University Hospital of Schleswig-Holstein in the years 2005 and 2006. Forty-one intraoperative perforations (20.4%) were documented and treated according to the following scheme: defects smaller than 5 mm were covered with a collagen membrane. Larger defects were additionally sutured. Particulated jawbone mixed 50 : 50 with bone substitute (25 cases) and a 50 : 50 mix of particulated iliac crest bone and BioOss (six cases) mainly served as graft material in the perforation group. In 12 cases, implants were installed at the time of sinus grafting, and in 27 cases, a second operation was performed. RESULTS Four sinus lift procedures had to be discontinued intraoperatively. Over a mean control interval of 162 days, one implant of the 93 inserted had to be replaced in the perforation group. After 1 year, the implant survival rate was 14 out of 14 in the perforation group vs. 81/92 in the control group. CONCLUSIONS With appropriate treatment, intraoperative sinus membrane perforations did not represent an elevated risk for implant loss, infectious complications or displacement of graft material in the investigated population.

Culture of cells gained from temporomandibular joint cartilage on non-absorbable scaffolds

The objective of this study was to investigate the adhesion, spreading and extracellular matrix synthesis of temporomandibular joint (TMJ) derived cells on non-absorbable scaffold materials to ultimately provide a durable stress-absorbent framework within tissue-engineered disc transplants. Scaffolds were prepared by polyamide monofilaments, expanded polytetrafluoroethylene (ePTFE) monofilaments, polyglycolic acid monofilaments (control) or natural bone mineral blocks (control). These scaffolds were incubated for 2, 4 and 8 weeks under common culture conditions with cells (human and porcine) harvested from the TMJ-disc or the articular eminence. The specimens were examined by scanning electron microscopy and transmission electron microscopy. The type of collagen synthesized was analyzed by SDS-PAGE. The cells were strongly adherent to all of the materials. Independent of their origin the cells became confluent on all scaffolds within four weeks. They filled recesses loosely and covered the constructs by an envelope of dense stratified cell layers. Moreover, the cells expressed collagen type II, which is specific for chondrocytes. Thus, it could be demonstrated, that ePTFE, polyamide, polyglycolic acid and natural bone mineral have an excellent compatibility in a three-dimensional cell culture system. ePTFE and polyamide scaffolds may be well suited for the development of tissue-engineered stress-resistant articular disc transplants.

The battle against multi-resistant strains: Renaissance of antimicrobial essential oils as a promising force to fight hospital-acquired infections

Hospital-acquired infections and antibiotic-resistant bacteria continue to be major health concerns worldwide. Particularly problematic is methicillin-resistant Staphylococcus aureus (MRSA) and its ability to cause severe soft tissue, bone or implant infections. First used by the Australian Aborigines, Tea tree oil and Eucalyptus oil (and several other essential oils) have each demonstrated promising efficacy against several bacteria and have been used clinically against multi-resistant strains. Several common and hospital-acquired bacterial and yeast isolates (6 Staphylococcus strains including MRSA, 4 Streptococcus strains and 3 Candida strains including Candida krusei) were tested for their susceptibility for Eucalyptus, Tea tree, Thyme white, Lavender, Lemon, Lemongrass, Cinnamon, Grapefruit, Clove Bud, Sandalwood, Peppermint, Kunzea and Sage oil with the agar diffusion test. Olive oil, Paraffin oil, Ethanol (70%), Povidone iodine, Chlorhexidine and hydrogen peroxide (H(2)O(2)) served as controls. Large prevailing effective zones of inhibition were observed for Thyme white, Lemon, Lemongrass and Cinnamon oil. The other oils also showed considerable efficacy. Remarkably, almost all tested oils demonstrated efficacy against hospital-acquired isolates and reference strains, whereas Olive and Paraffin oil from the control group produced no inhibition. As proven in vitro, essential oils represent a cheap and effective antiseptic topical treatment option even for antibiotic-resistant strains as MRSA and antimycotic-resistant Candida species.

Platelet-rich Plasma and Platelet-rich fibrin in human cell culture

OBJECTIVES The clinical use of platelet-rich plasma (PRP) for preprosthetic surgery has been a matter of controversy until now. Only recently, a new blood preparation has been developed which results in platelet-rich fibrin (PRF). The objective of the present investigation was to examine the growth factor release from PRP and PRF in vitro. STUDY DESIGN Whole blood samples from healthy participants (n = 10) were drawn to generate PRP and PRF. Human osteoblasts (O), human fibroblasts (F), and human osteoblast-derived osteosarcoma cells (Saos-2) were used for the cell culture. Cells of each cell line were cultivated, and PRP- or PRF-preparations added for ten days. The drawn medium was pooled and the quantities of growth factors (platelet-derived growth factor isomers AB and BB, insulin-like growth factor I, and transforming growth factor (TGF) isomers beta1 and beta2) analyzed by enzyme-linked immunosorbent assay. RESULTS In osteoblast and Saos-2 cultures, cytokine concentrations were significantly higher for PRP than for PRF (P < .05). In fibroblast cultures, results were the same with the exception of TGF-beta2 (P < .05). CONCLUSIONS This study demonstrates that PRP application in cell cultures leads to higher levels of growth factors than PRF application.

Facial attractiveness: visual impact of symmetry increases significantly towards the midline.

Symmetry is thought to be a major prerequisite for an attractive face. Many faces are not symmetric, yet are still regarded as beautiful. What role, then, does asymmetry play in the perception of beauty? We studied the assessment of computer-manipulated images by independent judges (n = 200–250): part A: nevi located at different positions; part B: standardized changes of the orbital region. The results showed that slight lateral orbital and facial asymmetry does not impair attractiveness at all and that asymmetries close to the midline are significantly less attractive than those affecting the lateral aspect of the face (P < 0.001). A single nevus which is located laterally on the face is significantly more attractive than a nevus close to the midline (P < 0.001). Faces with a completely symmetric bilateral pair of nevi in the same lateral positions (perceived as attractive when alone), received the worst ratings (P < 0.001). Symmetry is a characteristic of the attractive face, but there are exceptions to the rule. Under certain conditions symmetry can be completely unattractive. The visual impact of symmetry on the perception of beauty increases significantly when approaching the midline.

Penicillin compared with other advanced broad spectrum antibiotics regarding antibacterial activity against oral pathogens isolated from odontogenic abscesses

OBJECTIVES We examined the spectrum of oral pathogens found in odontogenic abscesses and their susceptibility to penicillin as well as to amoxicillin with clavulanic acid, doxycycline, clindamycin and moxifloxacin. The in vitro results were compared with clinical observations. PATIENTS AND METHODS One hundred and eighty eight swabs were obtained from 94 patients with odontogenic abscesses. Bacterial strains were isolated for susceptibility tests. The same patients were investigated for their clinical outcome after standard therapy. RESULTS A total of 517 bacterial strains were isolated from 94 patients. Ninety eight per cent of abscesses were polymicrobial. The most prevalent bacteria were Viridans streptococci representing 54% of the aerobic/facultative anaerobic bacteria. Prevotella spp. comprised 53% of the anaerobes. No multiresistant strains were detected. Susceptibility testing revealed a sensitivity of over 99% of aerobes/facultative aerobes and 96% of anaerobes sensitivity for moxifloxacin. The corresponding values for penicillin were lowest at 61% and 79%, respectively. In the clinical collective, patients with minor abscesses and no risk of further progression received surgical treatment without antibiotics (36%). Penicillin was administered additionally in 30%. Amoxicillin with clavulanic acid was given in 18% and clindamycin in 15%. Ninety two of the 94 patients showed significant recovery with the described treatment. Only in two cases was a change to the latest broader spectrum antibiotics necessary. CONCLUSION In contrast to the moderate in vitro results, penicillin successfully treated the pathogens derived from odontogenic abscess sufficiently when adequate surgical treatment was provided. One third of the patients was treated successfully with incision and drainage only. We suggest that one good reason for its clinical efficacy is the susceptibility of the dominant aerobe/facultative aerobe and anaerobe strains to penicillin.

Effects of bone morphogenetic protein‐7 stimulation on osteoblasts cultured on different biomaterials

The objective of the present study was to investigate the effects of an in vitro stimulation of human osteoblasts by recombinant human bone morphogenetic protein‐7 (rhBMP‐7) on the collagen types and the quantity of the collagen cross‐links synthesized in a three‐dimensional culture on various biomaterials for bone replacement. Trabecular bone chips were harvested from human iliac crests, and cell cultures were established at standard conditions. One hundred and fifty nanograms per milliliter of rhBMP‐7 was added. For the second passage a cell scraper was used to bring the cells into suspension, and 100 μl osteoblasts (at a density of 3.3 × 105) were transferred onto nine blocks of either Bio‐Oss®, Tutoplast®, or PepGen p‐15™. Blocks incubated with cells that were not treated with rhBMP‐7 served as controls. Cell colonization of the biomaterials was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) after a period of 2, 4, and 6 weeks. Throughout the experiment medium, supernatants were collected and collagen was characterized by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). Finally, the collagen cross‐link residues hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) were quantified by HPLC. Within 4 weeks the cells became confluent on all of the studied biomaterials. All samples synthesized bone specific LP and collagen type I. However, in rhBMP‐7‐stimulated samples, the amount of HP and LP found was increased by 45% compared to non‐stimulated samples. Cell proliferation and collagen synthesis was similar on the different biomaterials, but was consistently reduced in specimen not stimulated with rhBMP‐7. In vitro stimulation of osteoblasts on Bio‐Oss, Tutoplast, or PepGen p‐15 with rhBMP‐7 and subsequent transplantation of the constructs might lead to an enhanced osseointegration of the biomaterials in vivo. J. Cell. Biochem. 86: 90–98, 2002.

Gender and Nasal Shape : Measures for Rhinoplasty

Background: Gender-specific nasal shapes are recommended for rhinoplasty. This study was conducted to clarify whether there truly are gender-related differences and to determine optimal nasal shapes in a Caucasian population. Methods: The authors created female and male composite photographs of “average” (n = 128 each), “optimal” (n = 16 each), and “most unpleasant” (n = 8 each) noses stratified on the basis of each photographed subject’s (n = 311) own evaluation of the attractiveness of her or his nose, using a visual analogue scale. These composites were also assessed by 308 independent judges. Results: Optimal female noses showed a horizontally and vertically lower nasion and were concave to straight in profile as compared with optimal male noses, which had a vertically and horizontally higher nasion and a straight profile. A supratip break was not found in any of the composites. At least half of the judges rated average and optimal male composite noses as female. A significant majority mistook the composite of the most unpleasant female noses as male (frontal view, 62.0 percent; lateral view, 72.4 percent; p < 0.001). Optimal and average female and male noses were found to be independently significantly more attractive than the most unpleasant ones (p < 0.001, n = 308 judges). Women and men with a straight or concave profile were significantly (p = 0.017 and p = 0.006, respectively) more satisfied with the appearance of their nose than those with nasal humps. Conclusions: Gender-related differences in nasal shape appear to be subtle, with nasion position being one of the main factors. A nasal hump and a supratip break are not desirable.

HDR brachytherapy irradiation of the jaw - as a new experimental model of radiogenic bone damage

INTRODUCTION Hitherto, no suitable experimental model exists to test new treatments for radiogenic bone damage, such as new step from knowledge about bone growth factors or angiogenesis factors. The goal of this investigation was to establish such a standardised experimental model. MATERIAL AND METHODS Twenty-four rats were used in this study. In 12 rats a plastic tube was implanted along the right half of the mandible and treated with a single dose of 20 Gy at a high-dose-rate (HDR) using an afterloading machine, the remainder served as control (n=12). One hundred days after irradiation both sides of the mandible were examined using paraffin embedding and non-decalcified histology. RESULTS All HDR irradiated rats developed localised alopecia within 2 weeks of radiotherapy. In the irradiated group, a clear growth reduction of the ipsilateral incisor was observed. Paraffin histology revealed minimal damage of the bone structure with slightly increased signs of regeneration. The bone apposition rate was significantly reduced on the irradiated right side, compared with the left side (p=0.028). The average diameter of the mandibular condyles on the irradiated right sides was significantly reduced when compared with the left sides (p=0.023). CONCLUSIONS It is possible to induce radiogenic damage of the mandible by using HDR brachytherapy with a single dose of 20 Gy comparable to 45 x 2 Gy of conventional irradiation. This new model is easy and predictable and appears to be suitable for the testing of new treatment modalities. It is advantageous for the testing of bone growth and angiogenesis factors that the contralateral side exhibits completely normal bone apposition characteristics enabling a split-mouth design for future experiments.