Effect of zirconia surface treatments on the shear strength of zirconia/veneering ceramic composites

Aim of the investigation was to assess the effect of different surface treatments on the bond strength of veneering ceramics to zirconia. In a shear test, the influences of polishing, sandblasting, and silica-coating of the zirconia surface on bonding were assessed with five different veneering ceramics. In addition the effect of liner application was examined. With one veneering ceramic, the impact of regeneration firing of zirconia was also evaluated. Statistical analysis was performed with one-way ANOVA and post hoc Scheffé's test. Failure in every case occurred in the veneering ceramic adjacent to the interface with a thin layer of ceramic remaining on the zirconia surface, indicating that bond strength was higher than the cohesive strength of the veneering ceramic. Shear strength ranged from 23.5 +/- 3.4 MPa to 33.0 +/- 6.8 MPa without explicit correlation to the respective surface treatment. Regeneration firing significantly decreased the shear strength of both polished and sandblasted surfaces. Findings of this study revealed that bonding between veneering ceramics and zirconia might be based on chemical bonds. On this note, sandblasting was not a necessary surface pretreatment to enhance bond strength and that regeneration firing was not recommended.

Zirconia for teeth and implants

This case series reports on the use of nonsilica-based high-strength full ceramics for different prosthetic indications. Fifty-two consecutive patients received tooth- or implant-supported zirconia reconstructions during a 2-year period. The observation period for reexamination was 12 to 30 months. The most frequent indications were single crowns and short-span fixed partial dentures. A few implant superstructures were screw-retained, whereas all remaining restorations were cemented on natural teeth or zirconia implant abutments. Clinical examination included biologic (probing depths, bleeding on probing) and esthetic (Papilla Index) parameters, as well as technical complications. No implant was lost or caused any problems, but two teeth were lost after horizontal fracture. Overall, the periodontal parameters were favorable. Fractures of frameworks or implant abutments were not observed. Abutment-screw loosening occurred once for one premolar single crown. Furthermore, five implant crowns in the posterior region exhibited chipping of the porcelain veneering material. With regard to esthetics, no reconstructions were considered unacceptable, but three crowns were remade shortly after delivery. In this short-term study, it was observed that biologic, esthetic, and mechanical properties of zirconia were favorable, and the material could be used in various prosthetic indications on teeth or implants.

[Zirconia and removable partial dentures]

The present paper deals with the double crown technique in removable prosthodontics. New ceramic materials like zirconia are increasingly used in combination with CAD/CAM technologies for framework fabrication of fixed prosthesis, tooth- or implant-supported. However, zirconia is also a newly accepted material in removable prosthodontics. It replaces gold alloys for the fabrication of primary telescopic crowns. The Galvanoforming technology is preferably used to fabricate the secondary crowns. The combination of both techniques and materials results in a prosthetic reconstruction of high quality, optimum fit and good biocompatibility.

Experimental results on gravity driven fully condensing flows in vertical tubes, their agreement with theory, and their differences with shear driven flows' boundary-condition sensitivities

This doctoral thesis presents the experimental results along with a suitable synthesis with computational/theoretical results towards development of a reliable heat transfer correlation for a specific annular condensation flow regime inside a vertical tube. For fully condensing flows of pure vapor (FC-72) inside a vertical cylindrical tube of 6.6 mm diameter and 0.7 m length, the experimental measurements are shown to yield values of average heat transfer co-efficient, and approximate length of full condensation. The experimental conditions cover: mass flux G over a range of 2.9 kg/m2-s ≤ G ≤ 87.7 kg/m2-s, temperature difference ∆T (saturation temperature at the inlet pressure minus the mean condensing surface temperature) of 5 ºC to 45 ºC, and cases for which the length of full condensation xFC is in the range of 0 < xFC < 0.7 m. The range of flow conditions over which there is good agreement (within 15%) with the theory and its modeling assumptions has been identified. Additionally, the ranges of flow conditions for which there are significant discrepancies (between 15 -30% and greater than 30%) with theory have also been identified. The paper also refers to a brief set of key experimental results with regard to sensitivity of the flow to time-varying or quasi-steady (i.e. steady in the mean) impositions of pressure at both the inlet and the outlet. The experimental results support the updated theoretical/computational results that gravity dominated condensing flows do not allow such elliptic impositions.

Becoming most fully ourselves : gender, voice, and ritual in dissertations

The writing and defense of the dissertation serve both as demonstration one is able to do the work of a scholar and as a rite of initiation. In contrast to much academic writing, dissertations generally adhere to narrowly conceived notions of academic discourse. I explore this within the context of an academic community in which under-representation remains a serious issue. This dissertation is about women writing dissertations. I draw from conversations with fifteen women, in or beyond, the process; friends’ anecdotes; published accounts; and, autobiographically, my experience. I suggest the dissertation’s initiatory role is at least as important as its scholarly role; during the process one establishes a sense of self as scholar, writer, and researcher. Students come to the dissertation with some notion of self as writer and scholar – a culturally negotiated sense that is more, or less, congruent with the culturally established self required for successful completion of the dissertation. The degree of congruence (or alternatively, harmony and dissonance) shapes the process of doing a dissertation. I argue that both the community and the language in which dissertations must generally be written are gendered masculine. Negotiating a voice that is acceptable in a dissertation while maintain fidelity to a sense of who one is seems more problematic as one’s distance from the center of dominant culture increases. Believing that agency lies in altering the reiteration of such processes, I worked with my committee to find ways to alter the process yet still do a dissertation I write in a variety of voices – essay and poetry as well as analytical – play with visual qualities of text, and experiment with non-verbal interpretations. These don’t exhaust possibilities, but do give a sense of how the rich variety of expression found in academe cam be brought into the dissertation. I thus demonstrate that one need not reconstitute herself through characteristic academic discourse in order to be initiated into the community of scholars. I suggest both the desirability of encouraging flexibility in the language, form, and process, of dissertations, and the theoretical necessity for such flexibility if the academic community is to become diverse. The writing and defense of the dissertation serve both as demonstration one is able to do the work of a scholar and as a rite of initiation. In contrast to much academic writing, dissertations generally adhere to narrowly conceived notions of academic discourse. I explore this within the context of an academic community in which under-representation remains a serious issue. This dissertation is about women writing dissertations. I draw from conversations with fifteen women, in or beyond, the process; friends’ anecdotes; published accounts; and, autobiographically, my experience. I suggest the dissertation’s initiatory role is at least as important as its scholarly role; during the process one establishes a sense of self as scholar, writer, and researcher Students come to the dissertation with some notion of self as writer and scholar – a culturally negotiated sense that is more, or less, congruent with the culturally established self required for successful completion of the dissertation. The degree of congruence (or alternatively, harmony and dissonance) shapes the process of doing a dissertation. I argue that both the community and the language in which dissertations must generally be written are gendered masculine. Negotiating a voice that is acceptable in a dissertation while maintain fidelity to a sense of who one is seems more problematic as one’s distance from the center of dominant culture increases. Believing that agency lies in altering the reiteration of such processes, I worked with my committee to find ways to alter the process yet still do a dissertation I write in a variety of voices – essay and poetry as well as analytical – play with visual qualities of text, and experiment with non-verbal interpretations. These don’t exhaust possibilities, but do give a sense of how the rich variety of expression found in academe cam be brought into the dissertation. I thus demonstrate that one need not reconstitute herself through characteristic academic discourse in order to be initiated into the community of scholars. I suggest both the desirability of encouraging flexibility in the language, form, and process, of dissertations, and the theoretical necessity for such flexibility if the academic community is to become diverse. The writing and defense of the dissertation serve both as demonstration one is able to do the work of a scholar and as a rite of initiation. In contrast to much academic writing, dissertations generally adhere to narrowly conceived notions of academic discourse. I explore this within the context of an academic community in which under-representation remains a serious issue. This dissertation is about women writing dissertations. I draw from conversations with fifteen women, in or beyond, the process; friends’ anecdotes; published accounts; and, autobiographically, my experience. I suggest the dissertation’s initiatory role is at least as important as its scholarly role; during the process one establishes a sense of self as scholar, writer, and researcher Students come to the dissertation with some notion of self as writer and scholar – a culturally negotiated sense that is more, or less, congruent with the culturally established self required for successful completion of the dissertation. The degree of congruence (or alternatively, harmony and dissonance) shapes the process of doing a dissertation. I argue that both the community and the language in which dissertations must generally be written are gendered masculine. Negotiating a voice that is acceptable in a dissertation while maintain fidelity to a sense of who one is seems more problematic as one’s distance from the center of dominant culture increases. Believing that agency lies in altering the reiteration of such processes, I worked with my committee to find ways to alter the process yet still do a dissertation I write in a variety of voices – essay and poetry as well as analytical – play with visual qualities of text, and experiment with non-verbal interpretations. These don’t exhaust possibilities, but do give a sense of how the rich variety of expression found in academe cam be brought into the dissertation. I thus demonstrate that one need not reconstitute herself through characteristic academic discourse in order to be initiated into the community of scholars. I suggest both the desirability of encouraging flexibility in the language, form, and process, of dissertations, and the theoretical necessity for such flexibility if the academic community is to become diverse. The writing and defense of the dissertation serve both as demonstration one is able to do the work of a scholar and as a rite of initiation. In contrast to much academic writing, dissertations generally adhere to narrowly conceived notions of academic discourse. I explore this within the context of an academic community in which under-representation remains a serious issue. This dissertation is about women writing dissertations. I draw from conversations with fifteen women, in or beyond, the process; friends’ anecdotes; published accounts; and, autobiographically, my experience. I suggest the dissertation’s initiatory role is at least as important as its scholarly role; during the process one establishes a sense of self as scholar, writer, and researcher Students come to the dissertation with some notion of self as writer and scholar – a culturally negotiated sense that is more, or less, congruent with the culturally established self required for successful completion of the dissertation. The degree of congruence (or alternatively, harmony and dissonance) shapes the process of doing a dissertation. I argue that both the community and the language in which dissertations must generally be written are gendered masculine. Negotiating a voice that is acceptable in a dissertation while maintain fidelity to a sense of who one is seems more problematic as one’s distance from the center of dominant culture increases. Believing that agency lies in altering the reiteration of such processes, I worked with my committee to find ways to alter the process yet still do a dissertation I write in a variety of voices – essay and poetry as well as analytical – play with visual qualities of text, and experiment with non-verbal interpretations. These don’t exhaust possibilities, but do give a sense of how the rich variety of expression found in academe cam be brought into the dissertation. I thus demonstrate that one need not reconstitute herself through characteristic academic discourse in order to be initiated into the community of scholars. I suggest both the desirability of encouraging flexibility in the language, form, and process, of dissertations, and the theoretical necessity for such flexibility if the academic community is to become diverse.

Fixed mandibular and maxillary implant rehabilitation in a fully edentulous patient: a case report

The complete dental rehabilitation of a patient with a failing dentition using fixed implant-supported prostheses requires carefully planned and well-sequenced treatment. This case report presents the treatment steps and sequencing for a patient in whom removable provisional prostheses were not an option. While an immediate loading protocol was used in the mandible, a staged approach featuring strategic extractions and implant placement in several phases was applied in the maxilla. The major advantage of this treatment protocol was that the patient was maintained in fixed prostheses throughout the treatment.

[Rehabilitation of a periodontally compromised dentition with implant-supported zirconia bridges. Case report]

Clinical aspects of reconstruction with fix prosthesis and dental implants in a patient with a history of periodontitis is shown. A successful stabilization and rehabilitation of the periodontally involved dentition can be achieved with tooth-worn crown and bridge reconstructions. From a functional and aesthetic point of view the result may not be satisfying due to mobility and overlength of the teeth and open approximal spaces. Today, dentist and patient have often to weigh if teeth shall be maintained or replaced by dental implants. Thereby, both must be aware of the fact that in complex cases long-term success and aesthetic outcome may be difficult to predict. An intense discussion with the patient on his expectations, invasive treatment, risks with regard to biologic and prosthetic aspects is mandatory and must be based on the best scientific evidence available. The present case report shows different considerations and describes a radical solution which meets the patient's needs and is based on modern CAD-CAM technology.

Marked Silence, Neo-Feudalistic Reactions and the Stabilized Moral Regime – The Current De- and Reformation of „the Social“

The German chancellor and leader of the German conservative party, Angela Merkel, said in an interview a few weeks ago: “Nobody could have imagined a few months ago to what extent we would be pushed into state intervention programs. Of course, Merkel spoke on, this intervention is not easy for anybody. Therefore, she recommended turning back to the former course as soon as possible” (tagesschau.de, 11. März 2008, zit. nach Bildzeitungsinterview mit Angela Merkel, own translation). The worldwide celebrated new president of the United States, Barack Obama, said in an interview on CBS-News a few weeks before Merkel: “(...) there's no doubt that we have not been able yet to reset the confidence in the financial markets and in the consumer markets and among businesses that allow the economy to move forward in a strong way. And my job as president is gonna be to make sure that we restore that confidence“ (CBS News, 16. November 2008, Obama On Economic Crisis, Transition; http://www.cbsnews.com/stories/2008/11/16/60minutes/main4607893.shtml; Stand: 16. April 2009).

Are implants more reliable than severely compromised endodontically treated teeth as abutments for zirconia-based FPDs? : In vitro results of long-term preclinical load simulation

OBJECTIVES The aim was to study the impact of the defect size of endodontically treated incisors compared to dental implants as abutments on the survival of zirconia two-unit anterior cantilever-fixed partial dentures (2U-FPDs) during 10-year simulation. MATERIALS AND METHODS Human maxillary central incisors were endodontically treated and divided into three groups (n = 24): I, access cavities rebuilt with composite core; II, teeth decoronated and restored with composite; and III as II supported by fiber posts. In group IV, implants with individual zirconia abutments were used. Specimens were restored with zirconia 2U-FPDs and exposed to two sequences of thermal cycling and mechanical loading. Statistics: Kaplan-Meier; log-rank tests. RESULTS During TCML in group I two tooth fractures and two debondings with chipping were found. Solely chippings occurred in groups II (2×), IV (2×), and III (1×). No significant different survival was found for the different abutments (p = 0.085) or FPDs (p = 0.526). Load capability differed significantly between groups I (176 N) and III (670 N), and III and IV (324 N) (p < 0.024). CONCLUSION Within the limitations of an in vitro study, it can be concluded that zirconia-framework 2U-FPDs on decoronated teeth with/without post showed comparable in vitro reliability as restorations on implants. The results indicated that restorations on teeth with only access cavity perform worse in survival and linear loading. CLINICAL RELEVANCE Even severe defects do not justify per se a replacement of this particular tooth by a dental implant from load capability point of view.

Nonanimal stabilized hyaluronic acid for tissue augmentation of the dorsal hands: a prospective study on 38 patients

BACKGROUND Often ignored, hands are one of the most telltale signs of aging. This prospective study was initiated to evaluate the effect of subcutaneous hyaluronic acid (HA) injections in aging hands, with special attention to complications and long-term outcomes. METHODS Between January 2010 and December 2010, a total of 38 patients with skin phototypes II-IV and between 58 and 76 years old were treated with HA injection for aging hands. The quantity of injection never exceeded 1.0-1.5 ml HA per hand. A clinical follow-up was performed at 2 weeks, 4 weeks, 3 months, and 6 months after injection. Complications were reviewed for the whole series. At the first follow-up, 2 weeks after the procedure, ultrasound was carried out to determine if additional filling material was required. At each follow-up, patients were asked to fill out a satisfaction questionnaire. RESULTS Nine patients developed slight ecchymosis that disappeared after 1 week. No other complications were seen in the series. Pain during the injection and discomfort after the procedure were minimal. At the 2-week follow-up, after ultrasound control, nine patients received a complementary injection. At each follow-up, overall patient satisfaction was high and was validated by clearance of rhytids, veins, bony prominences, and dermal and subcutaneous atrophy. CONCLUSION Skin revitalization with injectable HA can improve the clinical appearance of the back of the hands. However, this therapy requires knowledge of the possible complications and their remediation as well as knowledge and respect of injected doses. Moreover, despite excellent results at each follow-up, the results of our series are not as good after 6 months, and a longer follow-up would be needed to determine if this procedure provides long-lasting benefit. LEVEL OF EVIDENCE III This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Fully automatic X-ray image segmentation via joint estimation of image displacements.

We propose a new method for fully-automatic landmark detection and shape segmentation in X-ray images. Our algorithm works by estimating the displacements from image patches to the (unknown) landmark positions and then integrating them via voting. The fundamental contribution is that, we jointly estimate the displacements from all patches to multiple landmarks together, by considering not only the training data but also geometric constraints on the test image. The various constraints constitute a convex objective function that can be solved efficiently. Validated on three challenging datasets, our method achieves high accuracy in landmark detection, and, combined with statistical shape model, gives a better performance in shape segmentation compared to the state-of-the-art methods.

Fully Automatic Segmentation of AP Pelvis X-rays via Random Forest Regression and Hierarchical Sparse Shape Composition

Knowledge of landmarks and contours in anteroposterior (AP) pelvis X-rays is invaluable for computer aided diagnosis, hip surgery planning and image-guided interventions. This paper presents a fully automatic and robust approach for landmarking and segmentation of both pelvis and femur in a conventional AP X-ray. Our approach is based on random forest regression and hierarchical sparse shape composition. Experiments conducted on 436 clinical AP pelvis x-rays show that our approach achieves an average point-to-curve error around 1.3 mm for femur and 2.2 mm for pelvis, both with success rates around 98%. Compared to existing methods, our approach exhibits better performance in both the robustness and the accuracy.

Short-term Functional and Patient Outcome of the Bi-cruciate Stabilized Total Knee Replacement: Prospective Consecutive Case-series

Background: Total knee replacement is the gold standard treatment for patients suffering from advanced symptomatic knee osteoarthritis. The main goals of knee prosthetics are pain reduction and restoration of knee motion. The new prostheses on the market such as the bi-cruciate stabilized Journey knee implant, promise a reconstruction of total physiological function of the knee with physiological range of motion and therefore high patient satisfaction. Purpose: The aim of this study was to analyze the patient-based Knee Injury and Osteoarthritis Outcome Score (KOOS) outcome after total knee replacement with new physiological bi-cruciate stabilized Journey knee prosthesis. Study Design: Prospective, consecutive case-series. Patients: Ninety nine patients, who received bi-cruciate stabilized Journey total knee prosthesis between January 1st 2006 and May 31st 2012, were included in the study. A single surgeon operated all patients. There were 61.1% females and the overall average age was 68 years (range 41-83 years). Left knee was replaced in 55.6%. Methods: The patients filled in KOO’s questionnaire pre- and 1 year postoperative. Range of motion (ROM) was studied preoperatively and at 1-year follow-ups. The pre- and postoperative KOOS subscores and ROM were compared using the Wilcoxon signed rank test. Results: There are significant improvements of all KOOS subscores. Ninety percent of patients have reached the minimum clinically relevant 10 points in symptoms, 94.5% in pain, 94.5% in activities of daily living, 84.9% in sport and recreation, and 90% in knee related quality of life. Postoperative, the average passive ROM was 131° (range 110-145°) and the average active ROM 122° (range 105-135°). The highest correlation coefficients ROM and the KOOS were observed for the activity and pain subscores. Very low or no correlation was seen for the sport subscore. Conclusions: Bi-cruciate stabilized knee prosthetic offers a solid outcome 1 year postoperative based on the results measured with the KOOS evaluation questionnaire. The Patients showed a generalized improvement in all domains measured in the KOOS of minimally 35, and up to over 52 points, what can be described as statistically significant. Patients described the level of functionality close to double compared to the preoperative status.

Acid and Alkaline Etching of Sandblasted Zirconia Implants: A Histomorphometric Study in Miniature Pigs.

BACKGROUND: Zirconia (ZrO2 ) has received interest as a dental material; however, little information is available on the impact of surface modifications on the osseointegration of zirconia implants. PURPOSE: The aim of the present study was to determine the effect of acid or alkaline etching of sandblasted ZrO2 implants on bone apposition in vivo. METHODS: Cylindrical ZrO2 implants with two circumferential grooves were placed in the maxilla of 12 miniature pigs. Biopsies were harvested after 1, 2, 4, and 8 weeks of healing. Undecalcified toluidine blue-stained ground sections were produced. The bone-to-implant contact, the bone area, and the presence of multinucleated giant cells were determined by histomorphometry. An uncorrected explorative statistical analysis was performed. RESULTS: Acid etching but not alkaline etching of sandblasted ZrO2 implants caused more bone-to-implant contact than sandblasted ZrO2 implants. The bone area was unaffected by the surface modifications. Acid and alkaline etching both increased the formation of multinucleated giant cells at the implant surface. CONCLUSIONS: This study provides a scientific basis to further investigate the impact of acid etching of sandblasted ZrO2 implants on osseointegration and the role of multinucleated giant cells in this process.