Alexander Gröbe

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.

Prognostic Relevance of Circulating Tumor Cells in Blood and Disseminated Tumor Cells in Bone Marrow of Patients with Squamous Cell Carcinoma of the Oral Cavity

Purpose: Current staging methods for squamous cell carcinomas (SCC) of the oral cavity (OSCC) need to be improved to predict the risk of individual patients. Because hematogenous tumor cell dissemination is a key event in tumor progression, we assessed the prognostic significance of disseminated tumor cells (DTC) in bone marrow and circulating tumor cells (CTC) in peripheral blood from patients with OSCC. Experimental Design: From 110 patients with OSCC, tumors were surgically resected (R0) without neoadjuvant therapy. The CellSearch system was used to enumerate CTCs. Bone marrow was aspirated from the iliac crest, and mononuclear cells (MNC) were enriched by Ficoll density gradient centrifugation. To detect DTCs, MNCs were immunostained with the pan-keratin antibody A45-B/B3. Results were correlated with clinicopathologic parameters and clinical outcome such as recurrence and death during follow-up time (mean 916 days). Results: Ten of 80 patients (12.5%) harbored CTCs in peripheral blood, whereas in 18 of 90 patients (20.0%) DTCs in bone marrow could be detected. Surprisingly, in only 2 patients (1.8%) CTCs and DTCs were detected simultaneously. Significant correlations could be found for CTCs and tumor size (P = 0.04), nodal status and DTCs (P = 0.02), and distant metastasis with CTCs (P = 0.004) and DTCs (P = 0.005). Univariate and multivariate analyses revealed that CTCs and DTCs were significant and independent predictors of recurrence-free survival (P < 0.001). Conclusions: Both DTCs and CTCs are independent prognostic markers in patients with OSCC, predicting relapse with higher sensitivity at various disease stages than routine staging procedures. Bone marrow might be an interesting target organ for future therapeutic interventions. Clin Cancer Res; 20(2); 425–33. ©2013 AACR.

Virtual dental surgery as a new educational tool in dental school

PURPOSE The virtual environment of the Voxel-Man simulator that was originally designed for virtual surgical procedures of the middle ear has been adapted to intraoral procedures. To assess application of the simulator to dentistry, virtual apicectomies were chosen as the pilot-test model. METHODS A group of 53 dental students provided their impressions after virtual simulation of apicectomies in the Voxel-Man simulator. RESULTS Fifty-one of the 53 students recommended the virtual simulation as an additional modality in dental education. The students indicated that the force feedback (e.g. simulation of haptic pressure), spatial 3D perception, and image resolution of the simulator were sufficient for virtual training of dental surgical procedures. CONCLUSION The feedback from dental students involved in this pilot-test has encouraged our interdisciplinary group to continue further development of the simulator with the goal of creating new training strategies in dental and medical education.

The detection of oral pre- malignant lesions with an autofluorescence based imaging system (VELscopeTM) – a single blinded clinical evaluation

The online version of the original article can be found at

Intraoperative efficiency of fluorescence imaging by Visually Enhanced Lesion Scope (VELscope®) in patients with bisphosphonate related osteonecrosis of the jaw (BRONJ)

OBJECTIVES The purpose of this study was to determine the potential of tissue fluorescence imaging by using Visually Enhanced Lesion Scope (VELscope) for the detection of osteonecrosis of the jaw induced by bisphosphonates (BRONJ). METHODS We investigated 20 patients (11 females and 9 males; mean age 74 years, standard deviation ± 6.4 years), over a period of 18 month with the diagnosis of BRONJ in this prospective cohort study. All patients received doxycycline as a fluorescending marker for osseous structures. VELscope has been used intraoperatively using the loss of fluorescence to detect presence of osteonecrosis. Osseous biopsies were taken to confirm definite histopathological diagnosis of BRONJ in each case. RESULTS Diagnosis of BRONJ was confirmed for every patient. In all patients except one, VELscope was sufficient to differentiate between healthy and necrotic bone by visual fluorescence retention (VFR) and visual fluorescence loss (VFL). 19 cases out of a total of 20 showed no signs of recurrence of BRONJ during follow-up (mean 12 months, range 4-18 months). CONCLUSION VELscope examination is a suitable tool to visualize necrotic areas of the bone in patients with bisphosphonate related osteonecrosis of the jaw. Loss of fluorescence in necrotic bone areas is useful intraoperatively as a tool for fluorescence-guided bone resection with relevant clinical interpretation.

Immunohistochemical and FISH analysis of EGFR and its prognostic value in patients with oral squamous cell carcinoma

OBJECTIVES To study immunohistochemical expression of the epithelial growth factor receptor (EGFR) in oral carcinomas and the head and neck region to examine possible associations with various features of the tumors and survival of the patients. MATERIALS AND METHODS Sections were made from two tissue arrays composed of 206 oral squamous cell carcinomas and 427 squamous cell carcinomas of the head and neck region, respectively, and examined for EGFR expression and Ki-67 labeling index by means of immunohistochemistry, and for EGFR gene amplification by means of fluorescence in situ hybridization. Correlation between resulting parameters and with clinical features was evaluated using chi-square test and Kaplan-Meyer analysis. RESULTS A statistically significant association was observed for strong EGFR immunohistochemical (IHC) expression with advanced lymph node involvement (P = 0.02). EGFR immunohistochemical expression did not significantly correlate with patient disease specific (DS) or overall survival (OS). EGFR gene amplification was not correlated with any of the tumor features nor to survival of the patients (DS and OS). DISCUSSION Epithelial growth factor receptor IHC expression and gene amplification might be suitable to predict locoregional control in oral squamous cell carcinoma patients but an inappropriate predictor for patients survival.

Leech Therapy in Reconstructive Maxillofacial Surgery

PURPOSE Corrective plastic surgery is indicated after accidents, burns, cancer surgery, or postoperative wound healing disorders with large tissue defects. The range of reconstructive techniques includes local skin flaps, pedicle grafts, and microvascular anastomosed flaps in the case of large defects. Main complications such as arterial and venous insufficiency caused by a vessel collapse or a vascular spasm are reported regularly in the area of anastomosed vessels and are the concern of any surgeon. Today, leeches are used if wound healing is at risk because of hemodynamic imbalance or a venous insufficiency. PATIENTS AND METHODS A retrospective evaluation of 148 patients who underwent medical leech therapy in the case of local or pedicaled flaps and some patients who had undergone reconstruction with microvascular flaps from 2005 and 2010 was conducted. Our sample had the typical symptoms of venous congestions of their flaps, despite suture removal, relief of pressure on the flap, and the elimination of a hematoma beyond the flap after surgery. Medical leech therapy was used in these cases. RESULTS Our series has confirmed the excellent and predictable healing after medical leech therapy for local and microsurgical anastomosed flaps in the case of venous congestion. CONCLUSION Leech therapy should be considered as a reliable additional procedure and an advantage in maxillofacial and plastic reconstructive surgery to remedy complications resulting from a hemodynamic imbalance or venous insufficiency in the immediate postoperative period.

Squamous cell carcinoma of the oral cavity and circulating tumour cells.

Due to a lack of substantial improvement in the outcome of patients suffering from oral squamous cell carcinoma (OSCC) during the past decades, current staging methods need to be revised. This disease is associated with poor survival rates despite considerable advances in diagnosis and treatment. The early detection of metastases is an important indicator of survival, prognosis and relapse. Therefore, a better understanding of the mechanisms underlying metastasis is crucial. Exploring alternative measures apart from common procedures is needed to identify new prognostic markers. Similar to previous findings predominantly for other solid tumours, recently published studies demonstrate that circulating tumour cells (CTCs) and disseminated tumour cells (DTCs) might serve as prognostic markers and could supplement routine staging in OSCC. Thus, the detection of CTCs/DTCs is a promising tool to determine the individual need for therapeutic intervention. Encouraging results and new approaches point to the future use of targeted therapies for OSCC, an exceedingly heterogeneous subgroup of head and neck cancer. This review focuses on summarising technologies currently used to detect CTCs/DTCs. The translational relevance for OSCC is highlighted. The inherent challenges in detecting CTCs/DTCs will be emphasised.

The use of navigation (BrainLAB Vector vision2) and intraoperative 3D imaging system (Siemens Arcadis Orbic 3D) in the treatment of gunshot wounds of the maxillofacial region

PurposeGunshot wounds are a rare occurance during times of peace. The removal of projectiles is recommended; in some cases, however, this is a controversy. The reproduction of a projectile image can be difficult if it is not adjacent to an anatomical landmark. Therefore, navigation systems give the surgeon continuous real-time orientation intraoperatively. The aim of this study was to report our experiences for image-guided removal of projectiles and the resulting intra- and postoperative complications.Patients and methodsWe investigated 50 patients retrospectively; 32 had image-guided surgical removal of projectiles in the oral and maxillofacial region. Eighteen had surgical removal of projectiles without navigation assistance.ResultsThere was a significant correlation (p = 0.0136) between the navigated surgery vs. not-navigated surgery and complicaton rate, including major bleeding (n = 4 vs. n = 1, 8% vs. 2%), soft tissue infections (n = 7 vs. n = 2, 14% vs. 4%), and nerval damage (n = 2 vs. n = 0, 4% vs. 0%; p = 0.038) and between the operating time and postoperative complications. A high tendency between operating time and navigated surgery (p = 0.1103) was shown. When using navigation system, we could reduce operating time.ConclusionIn conclusion, there is a significant correlation between reduced intra- and postoperative complications, including wound infections, nerval damage, and major bleeding, and the appropriate use of a navigation system. In all these cases, we could present reduced operating time. Cone-beam computed tomography plays an important role in detecting projectiles or metallic foreign bodies intraoperatively.

The use of buccal fat pad (BFP) as a pedicled graft in cleft palate surgery

The buccal fat pad (BFP) as pedicled graft was originally used in reconstructing medium sized intraoral defects. Promising results concerning the use of BFP in cleft palate surgery have been published recently. The aim of this article is to report on the use of BFP as a pedicled graft in cleft palate surgery and to discuss promising results for this reconstructive surgical concept. A retrospective evaluation of 24 patients who had BFP pedicled flaps used for the prevention and repair of Type III (Pittsburgh Fistula Classification) cleft palate fistulas, to obstruct the retromolar space of Ernst and in case of wide clefts, from 2005 to 2010, was conducted. In all cleft palate patients, the recipient area fully epithelialized within 4 weeks or less. No recurrence was seen and the donor site healed well without aesthetic or significant functional impairment. This series confirms the excellent and predictable healing of BFP intraorally and the minimal morbidity associated with the use of such grafts. The results of this study allow the authors to recommend that the BFP pedicled flap is considered as a reliable alternative procedure to expand the therapeutic options. The BFP graft provides an advantage in reconstructive cleft palate surgery.