Dan Brüllmann

Bisphosphonates: restrictions for vasculogenesis and angiogenesis: inhibition of cell function of endothelial progenitor cells and mature endothelial cells in vitro.

Bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) is one of the main side effects in patients treated with bisphosphonates for metastasis to the bone or osteoporosis. BP-ONJ usually occurs in patients treated with highly potent nitrogen-containing bisphosphonates. The exact mechanism of action and etiopathology is still unknown. In addition to inhibition of bone remodelling, an anti-angiogenetic effect has become the focus of research. The aim of these study was to investigate the effect of different bisphosphonates on human umbilicord vein endothelial cells (HUVEC) and endothelial progenitor cells (EPC), which play an important role in angiogenesis. Using varying concentrations, the impact of one non-nitrogen-containing bisphosphonate (clodronate) and three nitrogen-containing bisphosphonates (ibandronate, pamidronate and zoledronate) on HUVEC and EPC was analysed. The biologic behaviour of HUVEC after incubation with different bisphosphonates was measured in a Boyden migration assay as well as in a 3D angiogenesis assay. The number of apoptotic cells was measured by Tunnel assay. To underline the importance of neoangiogenesis in the context of BP-ONJ, we measured the EPC number after incubation with different bisphosphonates in vitro. HUVEC and EPC were significantly influenced by bisphosphonates at different concentrations compared with the non-treated control groups. The nitrogen-containing bisphosphonates pamidronate and zoledronate had the greatest impact on the cells, whereas clodronate followed by ibandronate was less distinct on cell function. These results underline the hypothesis that inhibited angiogenesis induced by bisphosphonates might be of relevance in the development and maintenance of BP-ONJ. The increased impact by highly potent bisphosphonates on HUVEC and EPC may explain the high prevalence of BP-ONJ in patients undergoing this treatment.

Correlation of cone beam computed tomography (CBCT) findings in the maxillary sinus with dental diagnoses: a retrospective cross-sectional study

This study was conducted to assess the coincidence of mucosal hyperplasia in the maxillary sinus and related clinical diagnoses of posterior maxillary teeth found in cone beam computed tomography (CBCT) scans. A total of 204 patients who underwent CBCT examinations between 2006 and 2008 were evaluated retrospectively. Clinical and CBCT findings were correlated using patient records. Absolute frequencies, odds ratios (OR), and 95% confidence intervals (95% CI) were calculated for statistical evaluations. There was a pronounced association between periodontitis and radiological signs of sinusitis. Basal mucosal wall thickening was more likely in patients with decayed and non-vital teeth compared to patients with sound teeth (OR = 5.2; 95% CI = 1.2–23.1). Basal mucosal wall thickening was also more likely than total mucosal thickening (OR = 10.4; 95% CI = 2.6–42.2). Patients with decayed and endodontically treated teeth were more likely to exhibit involvement of the basal wall (OR = 9.2; 95% CI = 3.3–25.2) than were patients with healthy teeth. CBCT examinations revealed a correlation between basal mucosal thickening in the maxillary sinus and decayed posterior maxillary teeth or periodontitis. Chronic symptoms involving the sinuses are one of the most common reasons for patients to consult physicians. One reason for chronic orofacial pain is the prevalence of undiagnosed sinus conditions.

Recognition of root canal orifices at a distance – a preliminary study of teledentistry

The remote recognition of root canal orifices was tested on 50 images of endodontically accessed teeth acquired with an intra-oral camera. The images were stored on a laptop computer and were presented to 20 observers who marked the visible canal orifices using software which stored the canal locations in standard files. The marked positions were verified on histological slices. In 87% of the cases, the canal locations were marked correctly. Inter-observer reliability depended on the location of the reviewed root canal (kappa = 0.44–0.77). The detection rate was related to the professional experience of the observers. The maximum proportion of accurate detections was found for the observers with more than 10 years of professional experience. The minimum proportion of accurate detections, 79%, was by the observer with one year of experience. The results of the study suggest that remote recognition of root canals by experienced dentists can help younger colleagues in the detection of root canal orifices.

Comparison of 4% articaine with epinephrine (1:100,000) and without epinephrine in inferior alveolar block for tooth extraction: double-blind randomized clinical trial of anesthetic efficacy

OBJECTIVE The purpose of this clinical prospective, randomized, double-blind study was to compare the anesthetic efficacy of 4% articaine with epinephrine (1:100,000) and without epinephrine in inferior alveolar nerve block anesthesia for extractions of mandibular teeth. STUDY DESIGN Eighty-eight patients received intraoral inferior alveolar nerve blocks using 4% articaine with 1:100,000 epinephrine (n = 41; group 1) or without epinephrine (n = 47; group 2) for extractions of mandibular teeth. The primary objectives were differences in onset as well as in length of soft tissue anesthesia. The amount of anesthetic solution, need of a second injection, pain while injecting, pain during treatment, postoperative pain, and possible complications were surveyed. RESULTS In both groups, anesthesia was sufficient for dental extractions. In group 1, a significantly faster onset of the anesthetic effect (7.2 min vs. 9.2 min; P = .001) and a significantly longer duration of soft tissue anesthesia (3.8 h vs. 2.5 h; P < .0001) were seen. There was no significant difference in the amount of anesthetic solution needed, in the need for a second injection, in the injection pain, in pain during treatment, or in postoperative analgesia. In both groups, no complications were seen. CONCLUSIONS To minimize the epinephrine-induced side effects, 4% articaine without epinephrine is a suitable anesthetic agent for dental extractions in the mandible after inferior alveolar nerve block anesthesia. There could be less postoperative discomfort due to the shorter duration of anesthesia without increased postoperative pain.

Promotion of Osteogenic Cell Response Using Quasicovalent Immobilized Fibronectin on Titanium Surfaces: Introduction of a Novel Biomimetic Layer System

PURPOSE Despite the undeniable potential of cell adhesion molecules such as fibronectin to support osteogenic cell responses and consecutive dental implant healing, the most beneficial mode of application onto titanium implant surfaces still requires investigation. Unspecific fibronectin adsorption on titanium dioxide (TiO(2)) surfaces can result in low-loading, high-desorption rates and protein-metal interactions with impaired biologic activity. The aim of the present study was to monitor the osteogenic cell responses (cell adhesion, proliferation, and differentiation) specifically to fibronectin biofunctionalized TiO(2). MATERIALS AND METHODS An innovative biomimetic streptavidin-biotin layer system allows flexible, but stable, specific binding of biotinylated biomolecules such as fibronectin on TiO(2) surfaces. Transparent glass disks were sputtered with TiO(2). The biomimetic layer system was immobilized by self-assembly and consisted of silane, biotin-derivate, streptavidin, and biotinylated fibronectin (bFN). For the control group, unbiotinylated fibronectin was directly coated onto TiO(2). Early cell adhesion dynamics were quantified using automated processing of light microscopy images within the first 24 hours. Relative mRNA expression of integrin-β1, cyclin D1, runt-related gene 2, alkaline phosphatase, and osteocalcin was obtained using quantitative real-time polymerase chain reactions 3 and 7 days after incubation. RESULTS Although untreated TiO(2) preserved a rather immature osteogenic phenotype, both unbiotinylated fibronectin and bFN promoted osteogenic cell adhesion and cell differentiation. In particular, runt-related gene 2 expression was significantly promoted by bFN after 3 days. In contrast, cyclin D1 expression was decreased for unbiotinylated fibronectin and bFN after 7 days. CONCLUSIONS The introduced biomimetic layer system contributes a coherent immobilization approach of adhesion molecules with promotion of osteogenic cell response in vitro.

Counting touching cell nuclei using fast ellipse detection to assess in vitro cell characteristics: a feasibility study

In this article, we describe a new image analysis software that allows rapid segmentation and separation of fluorescently stained cell nuclei using a fast ellipse detection algorithm. Detection time ranged between 1.84 and 3.14 s. Segmentation results were compared with manual evaluation. The achieved over-segmentation rate was 0.11 (0.1 double counts and 0.01 false positive detections), and the under-segmentation rate was of 0.03 over all images. We demonstrate the applicability of the proposed algorithm to automated counting of fluorescent-labeled cell nuclei and to tissue characterization. Moreover, the performance of the proposed algorithm is compared with preexisting automated image analysis techniques described by others.

Evaluation of ultrasound transmission velocity and 3-dimensional radiology in different bone types for dental implantology: a comparative ex vivo study.

OBJECTIVE To evaluate ultrasound transmission velocity (UTV) for assessment of mechanical bone quality, an ex vivo comparison of different bone types measured with UTV, 2-dimensional (2D) histomorphometry and with 3-dimensional (3D) radiology (cone-beam computerized tomography [CBCT], computerized microtomography [μCT]) was conducted. STUDY DESIGN Clinical cortical, cancellous, and mixed bone (each n = 6) was measured via UTV (m/s), CBCT (white pixel/black pixel ratio [WP/BP]), μCT (bone volume/total volume [μBV/TV]), and histomorphometry (bone volume/total volume [hBV/TV]). UTV values were correlated with 2D-histomorphometry and 3D-radiologic results. RESULTS For the cortical, cancellous, and mixed bone samples, respectively, UTV values were 1,945.17, 1,266.9,and 1472.2 m/s, WP/BP quotients were 0.96, 0.15, and 0.33, μBV/TV quotients were 0.94, 0.2, and 0.47, and hBV/TV quotients were 0.96, 0.24 and 0.39. Significant correlations between UTV and the other methods were seen (P < .0001). CONCLUSIONS Similar to the other methods, UTV is able to discriminate between different bone types ex vivo.

Early root surface colonization by human periodontal ligament fibroblasts following treatment with different biomaterials

Abstract Objectives. The present in-vitro study examined the effects of different biomaterials on early root surface colonization by human periodontal ligament (PDL) fibroblasts using confocal-laser-scanning-microscopy (CLSM). Materials and methods. Fifteen periodontally-diseased teeth were extracted, treated with scaling/root planing and longitudinally cut to obtain 30 root fragments. Fragments were treated either with 24% EDTA following application of enamel matrix derivative (EMD), 24% EDTA or EMD only, nanocrystalline hydroxyapatite (NHA) paste or oily calcium hydroxide suspension (OCHS) for 1 h each. The analogue untreated root specimens served as controls. Root fragments were incubated with human PDL fibroblasts and cellular proliferation and morphology were evaluated after 1, 3, 5 and 8 days using CLSM-visualization and image recognition software. Results. The rate of cellular proliferation was different among treatment modalities examined (p = 0.019). Except treatment with NHA paste all treatment modalities improved cellular proliferation on root surfaces at all different points of time compared with the control specimens. A significant difference between treatment modalities was observed between EMD and NHA paste (p = 0.008). No synergistic effect could be demonstrated comparing root surface conditioning with 24% EDTA and EMD application compared to 24% EDTA or EMD application only. Conclusion. The present results suggest that initial root surface colonization by PDL fibroblasts may be enhanced by root surface conditioning with 24% EDTA and application of EMD, application of 24% EDTA or EMD alone and OCHS. The addition of 24% EDTA for root surface conditioning prior to EMD application provided no synergistic effects in terms of early root surface colonization by PDL fibroblasts.

Recognition of root canal orifices in video sequences as a future support system during endodontic treatment.

INTRODUCTION The objective of this study was to show the practical application of computer-aided techniques for detecting root canal orifices through the access cavity using a video camera mounted on a microscope. METHODS A minimum distance classification image recognition algorithm was tested in an in vitro study to assess the possibilities of computer-aided recognition of root canal orifices. A Motic DM143 digital stereo microscope (Motic Germany GmbH, Wetzlar, Germany) was used because it includes a video camera that can be connected via USB1.1 to any computer. RESULTS The newly developed software is capable of communicating with a video camera and can automatically detect the root canal orifices in all teeth used in this study. A total of 165 extracted human teeth (molars and premolars) were used as test data to collect 8,250 images via screenshots for the evaluation of the detection quality. The software provided a detection sensitivity of 90.1%, with only 11.9% of the images as false-positive detections. CONCLUSION The study shows that computer-aided recognition of root canal orifices with video cameras is possible.

Alignment of cone beam computed tomography data using intra-oral fiducial markers.

This article illustrates a new method to align and merge two partially overlapping volumes each of them generated by cone beam computed tomography (CBCT). The aggregate volume covers a larger area of investigation and is determined by localizing one fixed LEGO brick in both of the primal volumes. Based on the LEGO brick an approximate registration of the volumes is determined. Afterwards we improve the transformation by minimizing the difference in overlapping space. In this paper we present a method which automates these two steps and provides an aligned volume.