Ambivalence in Organizations: A Multilevel Approach

The experience of simultaneously positive and negative orientations toward a person, goal, task, idea, and such appears to be quite common in organizations, but it is poorly understood. We develop a multilevel perspective on ambivalence in organizations that demonstrates how this phenomenon is integral to certain cognitive and emotional processes and important outcomes. Specifically, we discuss the organizational triggers of ambivalence and the cognitive and emotional mechanisms through which ambivalence diffuses between the individual and collective levels of analysis. We offer an integrative framework of major responses to highly intense ambivalence (avoidance, domination, compromise, and holism) that is applicable to actors at the individual and collective levels. The positive and negative outcomes associated with each response, and the conditions under which each is most effective, are explored. Although ambivalence is uncomfortable for actors, it has the potential to foster growth in the actor as well as highly adaptive and effective behavior

Procera Allceram: Two Year Evaluation of the Fixed Partial Denture

INTRODUCTION: The demand for all-ceramic restorations has increased substantially because of their esthetics and biocompatibility. However, the indication for a fixed partial denture has been limited by numerous problems such as low breaking strength of conventional dental ceramic and complex manufacturing techniques. Procera AllCeram is a CAD/CAM system for complete ceramic restorations with a dry-sintered high-purity aluminium oxide core.Purpose: The aim of this study was to determine whether the Procera ceramic fixed partial denture is an acceptable treatment modality.Material and methods: Nine patients were treated with a total of ten fixed partial dentures of three units. The restorations were constructed with bilateral support and one pontic, according to the Procera AllCeram technique. The California Dental Association quality evaluation system was used for assessment of marginal integrity and esthetics after two years. RESULTS: Nine of ten fixed partial dentures (90%) showed no defects and were functioning well after two years. No caries or signs of gingivitis or periodontitis exceeding those found. CONCLUSION: The study confirms that for the observation period of two years, fixed partial dentures made by the Procera AllCeram method seem to be an acceptable treatment alternative

Three-Year Clinical Evaluation of in Ceram Zirconia Bridges.

INTRODUCTION: The demand for esthetic restorations has led to the development of materials that are metal free. These materials must have adequate strength to be an alternative for the fabrication of fixed partial dentures in posterior segments of the dental arches. PURPOSE: The aim of the present study was to investigate in a long-term perspective whether the strength of the In Ceram Zirconia material is sufficient for use in posterior bridges. MATERIAL AND METHODS: Sixteen patients, who were between 23 and 50 years of age, with indications for a fixed denture replacing premolar or molar, were examined for participation in the study. Eighteen bridges were constructed with one or two pontics and two abutments, one on each side of the pontic. The patients were informed about risks of, and alternatives to, the proposed therapy. The supporting teeth were prepared with chamfer finish line and lack ofsharp line angles. Impressions were made with a rigid standard tray with an A-silicone putty soft and light-body materials (Aquasil, Dentsply). The laboratory procedures were performed by a laboratory autho rised by the Vita supplier. Ten of the bridges were cemented permanently with zinc phosphate cement and eight with glass ionomer cement. Clinical evaluation of the bridges were performed according to the California Dental Association’s quality evaluation system. RESULT: After three year evaluation all eighteen bridges were without signs of or any change in colour, and marginal integrity. CONCLUSION: In Ceram Zirconia is a potential alternative for full ceramic bridges in the posterior segments

Our Collective Tensions: Paradox Research Community’s Response to COVID-19

In this commentary on three articles from dozens of paradox theory scholars on paradox approaches to examining the COVID-19 pandemic and how the COVID-19 pandemic informs paradox theory, the authors involved in coordinating the collection of three papers discuss the process of bringing together scholars from around the world to discuss the pandemic. Four other preeminent paradox theorists offer additional commentaries on the papers in this Collection

Soft and hard tissue response to an implant with a convergent collar in the esthetic area: preliminary report at 18 months

Aim: The purpose of this prospective cohort study was to investigate, over an 18-month period, soft and hard tissue response to a transmucosal implant with a convergent collar inserted in the anterior maxillary esthetic area. Materials and methods: From June 2013 to January 2014, 14 consecutive patients were enrolled (7 men and 7 women; mean age 63.7 ± 14 years) with 20 implants, needing at least one implant-supported restoration between the canines in the maxillary anterior esthetic area. Six months after hopeless tooth extraction and an alveolar socket graft, a transmucosal-type implant with convergent collar walls was inserted in a midcrestal position with mini-flap surgery. An impression was taken 2 months later, and a definitive abutment with a provisional restoration was positioned. The final restoration was seated 2 weeks later. Clinical parameters, photographs, radiographs, and impressions were taken at this timepoint, and after 6 and 18 months. Using dedicated software, radiographic analysis (to detect marginal bone-level changes) and cast analysis (to detect soft tissue vertical and horizontal changes) were performed. Results: At the 18-month follow-up, all implants were clinically osseointegrated, stable, and showed no sign of infection. At baseline, interproximal radiographs revealed no bone defect around the implant. After an initial minimal bone loss (0.09 ± 0.144 mm), radiographic analysis showed a stable condition of bone remodeling (mean value 0.09 ± 0.08; range 0.0 to 0.5 mm) at the 18-month follow-up. No statistically significant horizontal dimensional changes of the alveolar ridge were observed between each timepoint. Mean soft tissue levels significantly improved between baseline and 18 months. The mean heights of the mesial papilla (MP) and distal papilla (DP) changes were 0.38 ± 0.22 and 0.47 ± 0.31, respectively. The level of the labial gingival margin (LGM) was 1.01 ± 0.63. Periodontal parameters never exceeded the physiological levels. Conclusions: Within the limitations of this preliminary study, the analyzed implants produced positive results in these esthetically demanding cases. This outcome should encourage long-term studies in order to assess, through controlled clinical trials, whether this convergent collar design offers advantages over other designs. Furthermore, due to the peculiar crestal module, together with the use of delayed implant insertion and a postextraction ridge preservation technique with biomimetic hydroxyapatite, the analyzed implants seem to help prevent the negative bone remodeling typically associated with two-piece implant systems, but without the well-known drawbacks of traditionally designed transmucosal implants. Therefore, wherever crestal bone preservation is a critical issue for clinical success in the anterior maxillary area can be considered of particular interest

Clinical evaluation comparing the fit of all-ceramic crowns obtained from silicone and digital intraoral impressions

Objectives The aim of this study is to compare the fit of all-ceramic crowns fabricated from conventional silicone impressions with the fit of all-ceramic crowns fabricated from intraoral digital impressions. Methods Twenty patients with 26 posterior teeth with a prosthetic demand were selected for the study. Two crowns (Straumann-Zerion) were made for each preparation. One crown was fabricated from an intraoral digital impression system (IDI group; Cadent-iTero), and the other crown was fabricated from a conventional one-step silicone impression (CI group; Express Penta Putty and Body Light). To replicate the interface between the crown and the preparation, each crown was cemented on its corresponding clinical preparation with ultra-flow silicone (Express Ultra Light Body). Each crown was embedded in resin to stabilize the registered interface, cut in 2-mm-thick slices in a buco-lingual orientation. Internal misfit was measured in microns using stereomicroscopy with a magnification of ×40. Measurements were taken at different landmarks: margin, chamfer angle, axial, crest, and occlusal fosse. After checking for normality, data was analyzed using paired Student’s t test (α = 0.05). Results Fit values were significantly affected by the impression technique (p = 0.000). Mean internal misfit and mean marginal misfit were 111.40 μm (SD = 54.04)/80.29 μm (SD = 26.24) for the crowns of the IDI group and 173.00 μm (SD = 92.65)/133.51 μm (SD = 48.78) for the CI group. Conclusion All-ceramic crowns fabricated from intraoral digital impressions with parallel confocal technology demonstrated a clinically acceptable internal and marginal fit as conventional impression. Clinical significance Intraoral digital impressions as initial step to the digital workflow could further improve the marginal adaptation of all ceramic single crowns

Fibroblast Interaction with Different Abutment Surfaces: In Vitro Study

Background: Attaining an effective mucosal attachment to the transmucosal part of the implant could protect the peri-implant bone. Aim: To evaluate if chair side surface treatments (plasma of Argon and ultraviolet light) may affect fibroblast adhesion on different titanium surfaces designed for soft tissue healing. Methods: Grade 5 titanium discs with four different surface topographies were subdivided into 3 groups: argon-plasma; ultraviolet light, and no treatment. Cell morphology and adhesion tests were performed at 20 min, 24 h, and 72 h. Results: Qualitative observation of the surfaces performed at the SEM was in accordance with the anticipated features. Roughness values ranged from smooth (MAC Sa = 0.2) to very rough (XA Sa = 21). At 20 min, all the untreated surfaces presented hemispherical cells with reduced filopodia, while the cells on treated samples were more spread with broad lamellipodia. However, these differences in spreading behavior disappeared at 24 h and 72 h. Argon-plasma, but not UV, significantly increased the number of fibroblasts independently of the surface type but only at 20 min. Statistically, there was no surface in combination with a treatment that favored a greater cellular adhesion. Conclusions: Data showed potential biological benefits of treating implant abutment surfaces with the plasma of argon in relation to early-stage cell adhesion