Implants with Original and Non-Original Abutment Connections

AIM: To test in vitro the mechanical resistance, rotational misfit and failure mode of three original implant-abutment connections and to compare them to two connections between non-original abutments connected to one of the original implants. MATERIAL AND METHODS: Three different implants with small diameters (3.3 mm for Straumann Roxolid, 3.5 mm for Nobel Biocare Replace and Astra Tech Osseospeed TX) were connected with individualized titanium abutments. Twelve implants from each system were connected to their original abutments (Straumann CARES, Nobel Biocare Procera, Astra Tech Atlantis). Twenty-four Roxolid implants were connected with non-original abutments using CAD/CAM procedures from the other two manufacturers (12 Nobel Biocare Procera and 12 Astra Tech Atlantis). For the critical bending test, a Zwick/Roell 1475 machine and the Xpert Zwick/Roell software were used. RESULTS: The rotational misfit varied when comparing the different interfaces. The use of non-original grade V titanium abutments on Roxolid implants increased the force needed for deformation. The fracture mode was different with one of the original connections. CONCLUSIONS: Non-original abutments differ in design of the connecting surfaces and material and demonstrate higher rotational misfit. These differences may result in unexpected failure modes.

Mice overexpressing BAFF develop a commensal flora-dependent, IgA-associated nephropathy

B cell activation factor of the TNF family (BAFF) is a potent B cell survival factor. BAFF overexpressing transgenic mice (BAFF-Tg mice) exhibit features of autoimmune disease, including B cell hyperplasia and hypergammaglobulinemia, and develop fatal nephritis with age. However, basal serum IgA levels are also elevated, suggesting that the pathology in these mice may be more complex than initially appreciated. Consistent with this, we demonstrate here that BAFF-Tg mice have mesangial deposits of IgA along with high circulating levels of polymeric IgA that is aberrantly glycosylated. Renal disease in BAFF-Tg mice was associated with IgA, because serum IgA was highly elevated in nephritic mice and BAFF-Tg mice with genetic deletion of IgA exhibited less renal pathology. The presence of commensal flora was essential for the elevated serum IgA phenotype, and, unexpectedly, commensal bacteria-reactive IgA antibodies were found in the blood. These data illustrate how excess B cell survival signaling perturbs the normal balance with the microbiota, leading to a breach in the normal mucosal-peripheral compartmentalization. Such breaches may predispose the nonmucosal system to certain immune diseases. Indeed, we found that a subset of patients with IgA nephropathy had elevated serum levels of a proliferation inducing ligand (APRIL), a cytokine related to BAFF. These parallels between BAFF-Tg mice and human IgA nephropathy may provide a new framework to explore connections between mucosal environments and renal pathology.

A Process Model of the Formation of Spatial Presence Experiences

In order to bridge interdisciplinary differences in Presence research and to establish connections between Presence and “older” concepts of psychology and communication, a theoretical model of the formation of Spatial Presence is proposed. It is applicable to the exposure to different media and intended to unify the existing efforts to develop a theory of Presence. The model includes assumptions about attention allocation, mental models, and involvement, and considers the role of media factors and user characteristics as well, thus incorporating much previous work. It is argued that a commonly accepted model of Spatial Presence is the only solution to secure further progress within the international, interdisciplinary and multiple-paradigm community of Presence research.

Internal Models, Vestibular Cognition, and Mental Imagery: Conceptual Considerations

Vestibular cognition has recently gained attention. Despite numerous experimental and clinical demonstrations, it is not yet clear what vestibular cognition really is. For future research in vestibular cognition, adopting a computational approach will make it easier to explore the underlying mech- anisms. Indeed, most modeling approaches in vestibular science include a top-down or a priori component. We review recent Bayesian optimal observer models, and discuss in detail the conceptual value of prior assumptions, likelihood and posterior estimates for research in vestibular cognition. We then consider forward models in vestibular processing, which are required in order to distinguish between sensory input that is induced by active self-motion, and sensory input that is due to passive self-motion. We suggest that forward models are used not only in the service of estimating sensory states but they can also be drawn upon in an offline mode (e.g., spatial perspective transformations), in which interaction with sensory input is not desired. A computational approach to vestibular cogni- tion will help to discover connections across studies, and it will provide a more coherent framework for investigating vestibular cognition.

Photon-beam subsource sensitivity to the initial electron-beam parameters

One limitation to the widespread implementation of Monte Carlo (MC) patient dose-calculation algorithms for radiotherapy is the lack of a general and accurate source model of the accelerator radiation source. Our aim in this work is to investigate the sensitivity of the photon-beam subsource distributions in a MC source model (with target, primary collimator, and flattening filter photon subsources and an electron subsource) for 6- and 18-MV photon beams when the energy and radial distributions of initial electrons striking a linac target change. For this purpose, phase-space data (PSD) was calculated for various mean electron energies striking the target, various normally distributed electron energy spread, and various normally distributed electron radial intensity distributions. All PSD was analyzed in terms of energy, fluence, and energy fluence distributions, which were compared between the different parameter sets. The energy spread was found to have a negligible influence on the subsource distributions. The mean energy and radial intensity significantly changed the target subsource distribution shapes and intensities. For the primary collimator and flattening filter subsources, the distribution shapes of the fluence and energy fluence changed little for different mean electron energies striking the target, however, their relative intensity compared with the target subsource change, which can be accounted for by a scaling factor. This study indicates that adjustments to MC source models can likely be limited to adjusting the target subsource in conjunction with scaling the relative intensity and energy spectrum of the primary collimator, flattening filter, and electron subsources when the energy and radial distributions of the initial electron-beam change.

Proximity of premolar roots to maxillary sinus: a radiographic survey using cone-beam computed tomography.

INTRODUCTION The proximity of the roots of the posterior maxillary teeth to the maxillary sinus is a constant challenge to the dental practitioner. Because the majority of studies have assessed the relationship regarding molars, the present study focused on premolars. METHODS Cone-beam computed tomographic images of 192 patients were reconstructed in sagittal, coronal, and axial planes to quantify the distances between the root apices of the maxillary premolars and the adjacent maxillary sinus. Measurements were taken for each root, and data were correlated with age, sex, side, and presence of both or absence of 1 of the 2 premolars. RESULTS A total of 296 teeth (177 first and 119 second premolars) were evaluated. The mean distances from buccal roots of the first premolars to the border of the maxillary sinus in the sagittal, coronal, and axial planes ranged from 5.15 ± 2.99 to 8.28 ± 6.27 mm. From palatal roots, the mean distances ranged from 4.20 ± 3.69 to 7.17 ± 6.14 mm. The mean distances of second premolars were markedly shorter in buccal roots between 2.32 ± 2.19 and 3.28 ± 3.17 mm and in palatal roots between 2.68 ± 3.58 and 3.80 ± 3.71 mm, respectively. The frequency of a premolar root protrusion into the maxillary sinus was very low in first premolars (0%-7.2%) but higher in second premolars (2.5%-13.6%). Sex, age, side, and presence/absence of premolars failed to significantly influence the mean distances between premolar roots and the maxillary sinus. CONCLUSIONS Based on the calculated mean distances of the present study, only few premolars (and if so second premolars) would present a risk of violating the border of the maxillary sinus during conventional or surgical endodontic treatment or in case of tooth extraction.

Zevalin and BEAM (Z-BEAM) versus rituximab and BEAM (R-BEAM) conditioning chemotherapy prior to autologous stem cell transplantation in patients with mantle cell lymphoma.

Early relapse is common in patients with mantle cell lymphoma (MCL) highlighting the unmet need for further improvement of therapeutic options for these patients. CD20 inhibition combined with induction chemotherapy as well as consolidation with high-dose chemotherapy (HDCT) is increasingly considered cornerstones within current therapy algorithms of MCL whereas the role of radioimmunotherapy is unclear. This retrospective single center study compared 46 consecutive MCL patients receiving HDCT in first or second remission. Thirty-five patients had rituximab and BEAM (R-BEAM), and 11 patients received ibritumomab tiuxetan (Zevalin®), an Yttrium-90 labeled CD20 targeting antibody, prior to BEAM (Z-BEAM) followed by autologous stem cell transplantation (ASCT). We observed that the 5-year overall survival (OS) in the R-BEAM and Z-BEAM groups was 55% and 71% (p = 0.288), and the 4-year progression free survival (PFS) was 32% and 41%, respectively (p = 0.300). There were no treatment related deaths in both groups, and we observed no differences in toxicities, infection rates or engraftment. Our data suggest that the Z-BEAM conditioning regimen followed by ASCT is well tolerated, but was not associated with significantly improved survival compared to R-BEAM. Copyright © 2015 John Wiley & Sons, Ltd.

Detection of back-to-back proton pairs in charged-current neutrino interactions with the ArgoNeuT detector in the NuMI low energy beam line

Short range nucleon-nucleon correlations in nuclei (NN SRC) carry important information on nuclear structure and dynamics. NN SRC have been extensively probed through two-nucleon knock- out reactions in both pion and electron scattering experiments. We report here on the detection of two-nucleon knock-out events from neutrino interactions and discuss their topological features as possibly involving NN SRC content in the target argon nuclei. The ArgoNeuT detector in the Main Injector neutrino beam at Fermilab has recorded a sample of 30 fully reconstructed charged current events where the leading muon is accompanied by a pair of protons at the interaction vertex, 19 of which have both protons above the Fermi momentum of the Ar nucleus. Out of these 19 events, four are found with the two protons in a strictly back-to-back high momenta configuration directly observed in the final state and can be associated to nucleon Resonance pionless mechanisms involving a pre-existing short range correlated np pair in the nucleus. Another fraction (four events) of the remaining 15 events have a reconstructed back-to-back configuration of a np pair in the initial state, a signature compatible with one-body Quasi Elastic interaction on a neutron in a SRC pair. The detection of these two subsamples of the collected (mu- + 2p) events suggests that mechanisms directly involving nucleon-nucleon SRC pairs in the nucleus are active and can be efficiently explored in neutrino-argon interactions with the LAr TPC technology.

Changes of Root Length and Root-to-Crown Ratio after Apical Surgery: An Analysis by Using Cone-beam Computed Tomography

INTRODUCTION Apical surgery is an important treatment option for teeth with post-treatment periodontitis. Although apical surgery involves root-end resection, no morphometric data are yet available about root-end resection and its impact on the root-to-crown ratio (RCR). The present study assessed the length of apicectomy and calculated the loss of root length and changes of RCR after apical surgery. METHODS In a prospective clinical study, cone-beam computed tomography scans were taken preoperatively and postoperatively. From these images, the crown and root lengths of 61 roots (54 teeth in 47 patients) were measured before and after apical surgery. Data were collected relative to the cementoenamel junction (CEJ) as well as to the crestal bone level (CBL). One observer took all measurements twice (to calculate the intraobserver variability), and the means were used for further analysis. The following parameters were assessed for all treated teeth as well as for specific tooth groups: length of root-end resection and percentage change of root length, preoperative and postoperative RCRs, and percentage change of RCR after apical surgery. RESULTS The mean length of root-end resection was 3.58 ± 1.43 mm (relative to the CBL). This amounted to a loss of 33.2% of clinical and 26% of anatomic root length. There was an overall significant difference between the tooth groups (P < .05). There was also a statistically significant difference comparing mandibular and maxillary teeth (P < .05), but not for incisors/canines versus premolars/molars (P = .125). The mean preoperative and postoperative RCRs (relative to CEJ) were 1.83 and 1.35, respectively (P < .001). With regard to the CBL reference, the mean preoperative and postoperative RCRs were 1.08 and 0.71 (CBL), respectively (P < .001). The calculated changes of RCR after apical surgery were 24.8% relative to CEJ and 33.3% relative to CBL (P < .001). Across the different tooth groups, the mean RCR was not significantly different (P = .244 for CEJ and 0.114 for CBL). CONCLUSIONS This CBCT-based study demonstrated that the RCR is significantly changed after root-end resection in apical surgery irrespective of the clinical (CBL) or anatomic (CEJ) reference levels. The lowest, and thus clinically most critical, postoperative RCR was observed in maxillary incisors. Future clinical studies need to show the impact of resection length and RCR changes on the outcome of apical surgery.

Limits on muon-neutrino to tau-neutrino oscillations induced by a sterile neutrino state obtained by OPERA at the CNGS beam

The OPERA experiment, exposed to the CERN to Gran Sasso νµ beam, collected data from 2008 to 2012. Four oscillated ντ Charged Current interaction candidates have been detected in appearance mode, which are consistent with νµ → ντ oscillations at the atmospheric ∆m^2 within the “standard” three-neutrino framework. In this paper, the OPERA ντ appearance results are used to derive limits on the mixing parameters of a massive sterile neutrino.

Optimal sites for orthodontic mini-implant placement assessed by cone beam computed tomography

OBJECTIVES: To determine (1) the optimal sites for mini-implant placement in the maxilla and the mandible based on dimensional mapping of the interradicular spaces and cortical bone thickness and (2) The effect of age and sex on the studied anatomic measurements. MATERIAL AND METHODS: The cone beam computed tomography images of 100 patients (46 males, 54 females) divided into two age groups (13-18 years), and (19-27 years) were used. The following interradicular measurements were performed: (1) Buccolingual bone thickness; (2) Mesiodistal spaces both buccally and palatally/lingually; and (3) Buccal and palatal/lingual cortical thicknesses. RESULTS: In the maxilla, the highest buccolingual thickness existed between first and second molars; the highest mesiodistal buccal/palatal distances were between the second premolar and the first molar. The highest buccal cortical thickness was between the first and second premolars. The highest palatal cortical thickness was between central and lateral incisors. In the mandible, the highest buccolingual and buccal cortical thicknesses were between the first and second molars. The highest mesiodistal buccal distance was between the second premolar and the first molar. The highest mesiodistal lingual distance was between the first and second premolars. The highest lingual cortical thickness was between the canine and the first premolar. The males and the older age group had significantly higher buccolingual, buccal, and palatal cortical thicknesses at specific sites and levels in the maxilla and the mandible. CONCLUSIONS: A clinical guideline for optimal sites for mini-implant placement is suggested. Sex and age affected the anatomic measurements in certain areas in the maxilla and the mandible.

Morphology of the nasopalatine canal and dental implant surgery: a radiographic analysis of 100 consecutive patients using limited cone-beam computed tomography

To analyze the dimensions and anatomic characteristics of the nasopalatine canal and the corresponding buccal bone plate of the alveolar process, using limited cone-beam computed tomography (CBCT) imaging.