Search

Both commercially pure titanium and titanium alloys are established biomaterials for implantation in bone and are widely used today in dentistry. Titanium particulates have been shown in some patient clusters to induce cellular immune mediators responsible for type I and IV hypersensitivity reactions, causing amplified corrosion, osteolysis, and increased odds of implant failure. Systemically, titanium particles were found to affect varying organ tissues and cause potentially harmful effects. In vivo and vitro studies have shown that titanium dental implant corrosion can be induced by factors relating to bio-tribocorrosion. In this literature review, the consequences of titanium implant corrosion and particulate dissemination are discussed and later juxtaposed against a promising novel implant material, zirconia. Zirconia offers characteristics similar to titanium along with additional advantages such as being non-corrosive and having a lower propensity for inducing immune responses. From the mounting evidence discussed in this article, metal allergy testing would be advantageous for choosing an appropriate implant material to minimize potential adverse effects on cellular functions of local and diffuse tissues. Objective: This literature review aims to elucidate and describe mechanisms in which titanium implants may become corroded and induce cellular aberrations both locally and systemically in vivo. Implications of this study provide supportive evidence regarding the selection of appropriate biomaterials for implant patients susceptible to mounting a hypersensitivity reaction to titanium., Competing Interests: Declarations. Ethical approval and consent to participate: Not applicable. Consent for publication: Consent for publication was provided by all three authors: Dr. Weidemann, Dr. Noumbissi, and Alexander Swalsky, DDS Candidate. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Statement of Problem: Technical complication rates of standard metal-ceramic implant-supported posterior restorations are relatively high. Whether monolithic zirconia crowns represent a more successful alternative is unclear., Purpose: The purpose of this systematic review and meta-analysis was to compare the clinical outcomes of posterior monolithic zirconia and metal-ceramic implant-supported single crowns., Material and Methods: A search was conducted in MEDLINE, Scopus, Embase, Web of Science, and CENTRAL databases for randomized controlled trials up to April 2023 with a follow-up time of at least 1 year. Restoration and implant survival and failure rates, marginal bone loss (MBL), bleeding on probing (BOP), and technical complications were analyzed by 2 reviewers. Statistical analyses were conducted using the R-statistics software program. The risk of bias was assessed by the Cochrane Risk of Bias Tool 2 (RoB 2), and the certainty of evidence by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach., Results: A total of 11 out of 2030 records were identified by title and abstract, and 4 records were included after full-text analysis. The statistical analysis revealed no significant difference in MBL (MD -0.11, 95% CI: [-0.25; 0.03]), BOP (OR 0.66, 95% CI: [0.25; 1.77]), or implant failure (OR 1.30, 95% CI: [0.24; 7.08]). Monolithic zirconia presented significantly less chipping over 1 year (OR 0.17, 95% CI: [0.03; 0.99]). The chipping rate was 0% for monolithic zirconia and 7.61% for metal-ceramic. Based on a narrative review, the restoration survival rate was 97.5% in the monolithic zirconia group and 99.1% in the metal-ceramic group., Conclusions: Monolithic zirconia showed favorable short-term survival rates and had significantly less chipping over 1 year. Regarding MBL, BOP, and failure rates, both restoration types presented similar results at the 1-year follow-up., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The potential adverse health effects of antiperspirant use are of interest to patients, primary care providers, dermatologists, and pathologists. In rare instances, antiperspirants containing aluminum-zirconium complexes have been associated with granulomatous dermatoses despite being deemed non-sensitizing in experiments. In this case study, we present a detailed examination of an axillary granuloma in a 28-year-old female who had been using an aluminum-zirconium-based antiperspirant for several years and presented with a left axillary nodule that was excised and analyzed using scanning electron microscopy with energy-dispersive x-ray analysis (SEM/EDXA). Histopathological examination revealed a foreign body-type reaction with amphophilic granular material within giant cells that corresponded to collocated zirconium and aluminum on SEM/EDXA elemental maps. Our case adds to the limited reports of axillary granulomas related to aluminum-zirconium complexes. It illustrates the histopathological appearance and in situ distribution of the aluminum-zirconium complexes, supporting the formation of foreign body-type granulomas. Additionally, our case study illustrates the potential role of these compounds in such reactions and aims to increase awareness among pathologists and clinicians., (Published 2024. This article is a U.S. Government work and is in the public domain in the USA.)

Objectives: The aim of this study was to evaluate the amount of enamel tooth wear induced by different antagonistic ceramic crown materials in the posterior area within a follow-up period up to 24 months in function. A network meta-analysis was performed to assess the effect of the materials on the mean vertical loss (MVL) of the antagonist enamel tooth surface., Data: Main search terms used in combination: ceramic, dental materials, metal ceramic, tooth wear and dental enamel., Sources: An electronic search was conducted in PubMed/Medline, Embase, and Cochrane CENTRAL plus hand-searching., Study Selection: Eligibility criteria included clinical studies reporting on MVL on antagonist's tooth up to 24 months following the permanent crown placement. From a total of 5697 articles, 7 studies reporting on 261 crowns for 177 subjects with 3 ceramic materials (Lithium disilicate, metal-ceramic, monolithic zirconia) were included. Among all, metal-ceramic and zirconia caused significantly higher enamel tooth wear on antagonist teeth, representing 82.5 µm [54.4; 110.6]) and 40.1 µm [22.2; 58.0]) more MVL than natural teeth group. In contrast, lithium disilicate showed only 5.0 µm [-48.2; 58.1]) more MVL than occurs on opposing natural teeth., Conclusions: This systematic review demonstrated that prosthodontic ceramic materials produced significantly more antagonist enamel tooth wear than opposing natural enamel tooth wear, and ceramic material type was correlated to the degree of enamel tooth wear. Additional well-conducted, randomized controlled trials with homogeneous specimens are required due to inadequate sample size and number of the clinical studies included in the analyses., Clinical Significance: The amount of wear caused by different restorative materials has a high influence on the antagonistic natural teeth and should therefore be evaluated intensively by the dentist., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Oxidized zirconium (OxiniumTM) prostheses, made up of a metallic alloy of zirconium with a ceramic surface formed by oxidizing the outer layer, were developed as an alternative bearing surface to reduce polyethylene wear and decrease failure of total knee arthroplasty (TKA). We report a unique catastrophic failure of an Oxinium TKA with consequent accelerated wear and severe metallosis. Intraoperatively, we observed extensive wear grooving of the femoral component with exposure of the underlying silver layers and the complete wear of polyethylene on the medial side. Metallic debris had a peculiar arthrogram appearance, noted within the cut surface of the femur and tibia, indicative of the osteolysis that occurred, leading up to the failure of the implants. The histopathologic examination revealed a collection of macrophages with foreign-body reactions and black-pigmented metal-induced wear particles. Oxinium has clear benefits regarding superior wear properties; however, surgeons need to be aware that there is a risk of exposure to the underlying layers that may precede accelerated wear, deformation, and metallosis. Uncovering the deeper layers could result in the appearance of an arthrogram on plain radiographs. Early identification of polyethylene wear and prompt revision is crucial to avoid the rapid progression of subsequent metallosis and catastrophic implant failure, specifically when using oxidized zirconium components for TKA. To the best of our knowledge, this is the first report presenting a detailed histologic analysis to provide insight into the mechanisms of the failed Oxinium components.

Little information is available about enamel wear caused by zirconia brackets, an inadvertent side effect of orthodontic treatment. The purpose of this study was to examine potential enamel damage induced by contact with zirconia brackets. Sliding and impact wear simulations were performed using bovine enamel specimens positioned at a 25° slant to a zirconium ball to determine wear behaviour. Different chewing patterns, tapping and grinding, were simulated. Specimens were profiled using confocal laser scanning microscopy, and the mean maximum depth and surface roughness were measured. Scanning electron microscopy was also performed. The mean maximum depth of wear values differed according to the number of mastication cycles, with a higher number of cycles producing higher depths of wear. The facet wear depth was significantly greater with the tapping pattern than with the grinding pattern. Scanning electron microscopic observation of the wear facets revealed that surface textures at the edges were rougher than those at the centre of all facets. The results of this study indicated that enamel wear was induced by contact with zirconia brackets during the early period of mastication, and that the patterns and number of cycles of mastication affected the wear progression of enamel., (© 2022 Scandinavian Division of the International Association for Dental Research. Published by John Wiley & Sons Ltd.)

Environmental factors have been associated with the etiology of autism spectrum disorder ASD in recent times. The involvement of toxic metals in the generation of reactive oxygen species and their epigenetics effects have been implicated in ASD. This systemic review examines the association of toxic metals with autism in children. A systematic literature search was performed in scientific databases such as PubMed, Google scholar, and Scopus. Case-control studies evaluating toxic metal levels in different tissues of ASD children and comparing them to healthy children (control group) were identified. The Newcastle-Ottawa Scale was used to evaluate the risk of bias of the included studies. Six case-control studies with 425 study subjects met our inclusion criteria. A total of four studies indicated higher levels of As, Pb, Hg, Cd, Al, Sn, Sb, Ba, TI, W, and Zr in whole blood, RBC, in whole blood, RBC, and hair samples of children with autism compared with control suggestive of a greater toxic metal exposure (immediate and long-term). Three studies identified significantly higher concentrations of Cd, Pb and Hg in urine and hair samples of autistic children compared to control suggesting decreased excretion and possible high body burden of these metals. The findings from this review demonstrate that high levels of toxic metals are associated with ASD, therefore, critical care is necessary to reduce body burden of these metals in children with ASD as a major therapeutic strategy., (Copyright © 2021. Published by Elsevier Inc.)

Objective: The introduction of CAD/CAM and the development of zirconia-based restorations have allowed clinicians to use less expensive materials and faster manufacturing procedures. The purpose of the study was to analyze the differences, in terms of mechanical and biological complication, in multiunit zirconia fixed dental prosthesis (FPDs) on posterior implants produced using a digital workflow. Method and Materials . This study was a retrospective investigation, and patients treated with screw-retained monolithic or partial veneer FPDs on dental implants were selected. Periapical radiographs were taken at baseline and at the 3-year follow-up. Complications were recorded and classified as technical and biological ones., Results: The study population included 25 patients. The occlusal and interproximal corrections were not clinically significant. In the study sample, the survival rate and success rate of the FPDs after 3 years were 100% and 96%, respectively. One implant failed immediately after placement., Conclusion: Monolithic zirconia FPDs and partial veneer FPDs showed a 100% survival rate, presenting an interesting alternative to metal ceramic restorations. The partial veneer FPDs had a higher technical complication rate than the monolithic FPDs; however, no statistically significant difference was found., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2021 Paolo De Angelis et al.)

Introduction: Prosthetic dentistry has shifted toward prevention of caries occurrence surrounding restorative margin through the anti-demineralization process. This study examines the ability of nanohydroxyapatite (NHA) gel and Clinpro (CP) on enhancing resistance to demineralization of enamel and cementum at margin of restoration., Materials and Methods: Thirty extracted mandibular third molars were segregated at 1 mm above and below cementoenamel junction (CEJ) to separate CEJ portions and substituted with zirconia disks by bonding to crown and root portions with resin adhesive. The enamel and cementum area of 4 × 4 mm 2 neighboring zirconia was applied with either NHA or CP, while one group was left no treatment (NT) before demineralized with carbopal. Vickers hardness (VHN) of enamel and cementum was evaluated before material application ( B M ), after material application ( A M ), and after demineralization ( A D ). Analysis of variance (ANOVA) and post hoc multiple comparisons were used to justify for the significant difference ( α  = 0.05). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were determined for surface evaluations., Results: The mean ± SD of VHN for B M , A M , and A D for enamel and cementum was 393.24 ± 26.27, 392.89 ± 17.22, 155.00 ± 5.68 and 69.89 ± 4.59, 66.28 ± 3.61, 18.13 ± 0.54 for NT groups, respectively, 390.10 ± 17.69, 406.77 ± 12.86, 181.55 ± 7.99 and 56.01 ± 9.26, 62.71 ± 6.15, 19.09 ± 1.16 for NHA groups, respectively, and 387.90 ± 18.07, 405.91 ± 9.83, 188.95 ± 7.43 and 54.68 ± 7.30, 61.81 ± 4.30, 19.22 ± 1.25 for CP groups, respectively. ANOVA indicated a significant increase in anti-demineralization of enamel and cementum upon application of NHA or CP ( p < 0.05). Multiple comparisons indicated the capability in inducing surface strengthening to resist demineralization for enamel and cementum of NHA which was comparable to CP ( p > 0.05) as evidenced by SEM and XRD data indicating NHA and CP deposition and crystallinity accumulation., Conclusion: NHA and CP were capable of enhancing anti-demineralization for enamel and cementum. The capability in resisting the demineralization process of NHA was comparable with CP. NHA was highly recommended for anti-demineralization for enamel and cementum surrounding restorative margin., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2021 Niwut Juntavee et al.)

Objective: Long-term clinical data on the success and complication rates of monolithic or minimally veneered zirconia implant-supported restorations are lacking. Hence, the purpose of this retrospective clinical study was to analyze the complications of monolithic or partially veneered zirconia implant-supported restorations up to 5 years follow-up. Material and Methods . Single crowns, bridges, and full-arch rehabilitations were included. The selection process was achieved by reviewing data from the prosthetic laboratory and excluding cases in which zirconium and full-ceramic coating restorations were used. A total of 154 restorations were included (82 monolithic and 72 with buccal ceramic stratification). All the complications encountered, and the solutions applied, were explained., Results: A total of 93 restorative units had a follow-up of between 24 and 60 months, and 61 restoration units had a follow-up of between 12 and 24 months. A total of 7 complications were encountered (14.58% of cases; 95.45% per prosthetic unit). The technical complication rate was 2.08% (one case of minor chipping in one prosthetic unit); regarding the mechanical complications, four decementations (8.33% of the cases) and two screw loosening (4.17% of the cases) were encountered., Conclusions: Considering the limitations of this study, it can be concluded that monolithic or partially veneered zirconia implant-supported restorations have a good clinical behavior during a follow-up period of up to 5 years., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2020 Markel Diéguez-Pereira et al.)

Increasing evidence from toxicological and epidemiological studies indicates that the brain is an important target for ambient (ultrafine) particles. Disturbance of redox-homeostasis and inflammation in the brain are proposed as possible mechanisms that can contribute to neurotoxic and neurodegenerative effects. Whether and how engineered nanoparticles (NPs) may cause neurotoxicity and promote neurodegenerative diseases such as Alzheimer's disease (AD) is largely unstudied. We have assessed the neurological effects of subacute inhalation exposures (4 mg/m 3 for 3 h/day, 5 days/week for 4 weeks) to cerium dioxide (CeO 2 ) NPs doped with different amounts of zirconium (Zr, 0%, 27% and 78%), to address the influence of particle redox-activity in the 5xFAD transgenic mouse model of AD. Four weeks post-exposure, effects on behaviour were evaluated and brain tissues were analysed for amyloid-β plaque formation and reactive microglia (Iba-1 staining). Behaviour was also evaluated in concurrently exposed non-transgenic C57BL/6J littermates, as well as in Western diet-fed apolipoprotein E-deficient (ApoE -/- ) mice as a model of vascular disease. Markers of inflammation and oxidative stress were evaluated in brain cortex. The brains of the NP-exposed 5xFAD mice revealed no accelerated amyloid-β plaque formation. No significant treatment-related behaviour impairments were observed in the healthy C57BL/6J mice. In the 5xFAD and ApoE -/- models, the NP inhalation exposures did not affect the alternation score in the X-maze indicating absence of spatial working memory deficits. However, following inhalation exposure to the 78% Zr-doped CeO 2 NPs changes in forced motor performance (string suspension) and exploratory motor activity (X-maze) were observed in ApoE -/- and 5xFAD mice, respectively. Exposure to the 78% doped NPs also caused increased cortical expression of glial fibrillary acidic protein (GFAP) in the C57BL/6J mice. No significant treatment-related changes neuroinflammation and oxidative stress were observed in the 5xFAD and ApoE -/- mice. Our study findings reveal that subacute inhalation exposure to CeO 2 NPs does not accelerate the AD-like phenotype of the 5xFAD model. Further investigation is warranted to unravel whether the redox-activity dependent effects on motor activity as observed in the mouse models of AD and vascular disease result from specific neurotoxic effects of these NPs., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Forms of interstitial pneumonia secondary to exposure to an air-contaminant are varied and so far, insufficiently described., Objectives/methods: We report here a case of a 57-year-old patient managed in our department for the exploration of MRC grade 2 dyspnoea and interstitial pneumonia. He mentioned multiple occupational and domestic exposures such as hens' excrements, asbestos and metal particles; he also had a previous history of smoking., Results: High-resolution computed tomography showed ground glass opacities predominating in posterior territories and surrounding cystic lesions or emphysematous destruction. The entire etiological assessment revealed only macrophagic alveolitis with giant multinucleated cells on the bronchoalveolar lavage. A surgical lung biopsy allowed us to refine the diagnosis with evidence of desquamative interstitial pneumonia and pulmonary granulomatosis. Finally, the analysis of the mineral particles in the biopsy revealed abnormally high rates of Zirconium and Aluminium. We were therefore able to conclude to a desquamative interstitial pneumonia associated with pulmonary granulomatosis linked to metal exposure (Aluminium and Zirconium). The clinical, functional and radiological evolution was favorable after a systemic corticosteroid treatment with progressive decay over one year., Conclusion: This presentation reports the first case to our knowledge of desquamative interstitial pneumonitis related to exposure to Zirconium and the third one in the context of Aluminium exposure. The detailed analysis of the mineral particles present on the surgical lung biopsy allows for the identification of the relevant particle to refine the etiological diagnosis, to guide the therapeutic management and to give access to recognition as an occupational disease. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (1): 79-84) ., (Copyright: © 2020 SARCOIDOSIS VASCULITIS AND DIFFUSE LUNG DISEASES.)

Objectives: To compare the survival rate of abutments, marginal bone loss and peri-implant soft tissue discoloration among implant-supported single crowns with different abutment materials., Data: Randomized controlled trials (RCTs), controlled clinical trials, and cohort studies of implant-supported single crowns with different dental abutment materials., Sources: A systematic search was conducted by an electronic search in 6 databases without restrictions on September 16, 2018, complemented by a manual search. "Grey" literatures were also searched., Study Selection: Of 3417 studies initially retrieved, thirteen were eligible for inclusion. After studies selected and data extraction, pair-wise and network meta-analyses were performed to analyze the survival rate of the abutment, the marginal bone loss and the soft tissue discoloration. The risk of bias was assessed based on the Cochrane guidelines, Newcastle-Ottawa scale, and funnel plots. Statistical heterogeneity, inconsistencies, and cumulative ranking were also evaluated., Results: Fourteen RCTs and nine non-RCTs were included. No significant differences was detected among titanium (Ti), zirconia (Zr), gold (Au), and alumina (Al) abutments in terms of survival rate (excluding Al < Ti (P < 0.05), marginal bone loss (excluding Zr  < Ti (P < 0.05) and Au  > Zr (P < 0.05)), or discoloration of peri-implant soft tissue. Additionally, Ti abutment had the highest cumulative ranking of survival rate (97.9%); Al abutment had the lowest marginal bone loss (81.4%) and Zr abutment had the least discoloration of peri-implant soft tissue (84.8%)., Conclusions: Ti abutment has a comparable survival rate with Zr, but better than Al. In addition, Zr abutment has a better effect in maintaining the marginal bone level, compared with Au and Ti. However, there was no difference in the discoloration of peri-implant soft tissue among Au, Ti, and Zr abutment., Clinical Significance: Based on the results of our network meta-analysis, Zr might be a recommended abutment material considering the clinical efficacy of implant-supported single crowns., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Although positron emission tomography (PET) imaging with 18-Fluorodeoxyglucose ( 18 F-FDG) is a promising technique in multiple myeloma (MM), the development of other radiopharmaceuticals seems relevant. CD138 is currently used as a standard marker for the identification of myeloma cells and could be used in phenotype tumor imaging. In this study, we used an anti-CD138 murine antibody (9E7.4) radiolabeled with copper-64 ( 64 Cu) or zirconium-89 ( 89 Zr) and compared them in a syngeneic mouse model to select the optimal tracers for MM PET imaging. Then, 9E7.4 was conjugated to TE2A-benzyl isothiocyanate (TE2A) and desferrioxamine (DFO) chelators for 64 Cu and 89 Zr labeling, respectively. 64 Cu-TE2A-9E7.4 and 89 Zr-DFO-9E7.4 antibodies were evaluated by PET imaging and biodistribution studies in C57BL/KaLwRij mice bearing either 5T33-MM subcutaneous tumors or bone lesions and were compared to 18 F-FDG-PET imaging. In biodistribution and PET studies, 64 Cu-TE2A-9E7.4 and 89 Zr-DFO-9E7.4 displayed comparable good tumor uptake of subcutaneous tumors. On the bone lesions, PET imaging with 64 Cu-TE2A-9E7.4 and 89 Zr-DFO-9E7.4 showed higher uptake than with 18 F-FDG-PET. Comparison of both 9E7.4 conjugates revealed higher nonspecific bone uptakes of 89 Zr-DFO-9E7.4 than 64 Cu-TE2A-9E7.4. Because of free 89 Zr's tropism for bone when using 89 Zr-anti-CD138, 64 Cu-anti-CD138 antibody had the most optimal tumor-to-nontarget tissue ratios for translation into humans as a specific new imaging radiopharmaceutical agent in MM.

Two zirconia-based 4-unit restorations intended for the same patient fractured during the veneering process even though the prolonged cooling protocol recommended by the manufacturers was used. Fractographic analyses revealed that both restorations fractured as a result of thermal shock, but at different times during production. Further investigation is necessary to optimize the firing protocols for large zirconia-based restorations and avoid fracture due to thermal shock., (Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objectives: To evaluate the clinical behavior of one-piece complete-coverage crowns and fixed partial dentures (FPDs) on teeth with vertical preparation without finish line biologically oriented preparation technique (BOPT)., Methods and Materials: This prospective study included 52 patients requiring treatment with restorations in the esthetic region: 74 crowns and 27 FPDs. The sample included a total of 149 teeth that were prepared vertically without finish line. The sample was divided into two groups: one-piece crowns and FPDs, all with zirconia cores, feldspathic ceramic veneer, and a 0.5-mm prosthetic finish line of zirconia. All procedures were carried out at the University of Valencia from 2013 to 2014. The following parameters were evaluated over a two-year follow-up: oral hygiene, periodontal state, gingival thickening, gingival margin stability, the presence of complications, and restoration survival rate. Patient satisfaction with treatment was assessed by means of a visual analogue scale (VAS)., Results: Two years after treatment, 80.5% of treated teeth remained free of gingival inflammation and bleeding. Mean gingival thickening was 0.41 ± 0.28 mm for one-piece crowns and 0.38 ± 0.36 mm for FPDs. Gingival margin stability was 100%, but 2% of the sample presented biological complications. The VAS patient satisfaction scores were eight out of a maximum score of 10., Conclusions: Two years after treatment, vertical preparation without finish line produces gingival thickening, margin stability, and optimal esthetics. Neither crowns nor FPDs presented any mechanical complications.

Objectives: The aim of this study was to assess the clinical outcomes and patient satisfaction with monolithic zirconia crowns in patients with severe tooth wear (≥1/3 of the tooth crown) in the aesthetic zone., Methods: The historical prospective study sample consisted of 13 patients previously treated with a total of 84 monolithic zirconia crowns. The patients had been treated in a private clinic in Bergen, Norway, in the period 2012 to 2014. All patients were men, aged 35-67 years (mean age 56.3 years) and had been in need of prosthetic rehabilitation because of severe tooth wear in the aesthetic zone. Technical complications as well as biologic findings were registered when the crowns had been in function one to three years (mean 20 months). The patients completed a self-administered questionnaire regarding satisfaction with aesthetic and function., Results: No biological complications were registered in 79 of the crowns (94%), and technical complications were registered in only two patients. All patients were satisfied with the aesthetic and function of the monolithic zirconia crowns and would choose the same treatment modality if they were to be treated again., Conclusions: Within the limitations of this study, we conclude that the rate of clinical complications was low and that the patients were satisfied with the aesthetic as well as the function of the monolithic zirconia crowns., Clinical Significance: Monolithic zirconia crowns may provide a valid treatment modality in the aesthetic zone in patients with severe tooth wear., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Improvements of soft tissue to the abutment surface results in more stable peri-implant conditions, however, few human histological studies have compared soft tissue responses around different abutment materials., Purpose: To describe the peri-implant tissue around 3 abutment materials; titanium, zirconia, and gold alloy, over an 8-week healing period., Materials and Methods: Fifteen edentulous sites were treated with implants. Eight weeks later, peri-implant tissue was harvested and processed using a nonseparation resin embedded technique. The tissue attachment characteristics were assessed at clinical stages using the gingival index (GI) score, surgical stage (surgical score), and histological stage (histological attachment percentage). Additionally, the inflammatory responses were evaluated using inflammatory extent and inflammatory cellularity grades. Nonparametrical statistics were used to describe the GI and surgical scores, and analytical statistics were used to analyze the histological attachment percentages as well as the inflammatory extent and cellularity grades amongst the 3 groups., Results: There were no statistically significant differences among the groups for GI score (P = .071) and surgical score (P = .262). Titanium and zirconia exhibited nearly similar mean histological attachment percentages while gold alloy had a significantly lower percentage (P = .004). For the inflammatory extent and cellularity grades, the odds of being one grade higher for gold alloy abutment was 5.18 and 17.8 times that of titanium abutment, respectively. However, for the zirconia abutment, the odds were 0.87 and 7.5 times higher than the titanium group., Conclusions: The tissue around the gold alloy abutments resulted in worse attachment conditions compared with the titanium and zirconia abutments. Inflammation tended to be higher in the tissue around the gold alloy abutments than the titanium and zirconia abutments., (© 2017 Wiley Periodicals, Inc.)

Objectives: The implant abutments, which had their own colour, might cause the discoloration of peri-implant mucosa. We aimed to appraise trails comparing the discoloration of peri-implant soft tissue around zirconia and titanium or golden abutments, the tints of which were vastly different., Data: We included randomized controlled trials (RCTs), controlled clinical trials (CCTs), cohort studies with patients rehabilitated with zirconia, titanium or golden implant abutments, quantitatively comparing the discoloration of peri-implant soft tissue according to CIE-Lab colour scale., Sources: A systematic search was conducted in PubMed, EMBASE, CDSR, and CENTRAL databases without any restriction on September 23, 2017. "Grey" literatures were also searched. A manual search was carried out as well., Study Selection: Of 584 articles initially retrieved, eight were eligible for inclusion. After data extraction, meta-analyses with mean differences (MDs) and their 95% confidence intervals (CIs) were employed. Moreover, the risk of bias within or across studies was assessed by Cochrane Collaboration's tool for assessing risk, the Newcastle-Ottawa scale, funnel plots, or Egger's test., Results: Four RCTs and four cohort studies were included. Soft-tissue discoloration around zirconia abutments was significantly less likely compared to that around titanium abutments (MD = -1.84; 95% CI = -3.62 to -0.07; P = 0.04 < 0.05) or golden abutments (MD = -0.90; 95% CI = -1.60 to -0.20; P = 0.01 < 0.05)., Conclusions: Zirconia abutments with white tint compared to grey titanium or golden abutments seem to restore a more appropriate colour match between peri-implant mucosa and natural teeth., Clinical Significance: Based on the present evidence, the "nature-like" zirconia abutments should be applied more often in the clinic., Prospero Registration Number: CRD42017075930., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Statement of Problem: Studies of composite resin repairs of yttrium-tetragonal zirconia polycrystal (Y-TZP) are usually performed in its tetragonal phase, but it may be partially transformed into a monoclinic phase in a clinical fracture., Purpose: The purpose of this in vitro study was to evaluate the effect of airborne-particle abrasion (APA) and a bonding agent on the shear bond strength (SBS) between a composite resin and hydrothermally aged Y-TZP., Material and Methods: Specimens (7.0×7.0×1.7 mm, N=112) of Y-TZP Lava were obtained, and 50% were aged in an autoclave at 134°C at 300 kPa for 8 hours. The surfaces were treated with APA 50-μm Al 2 O 3 particles (ALU) or Rocatec Soft (30 μm) (ROC) followed by Clearfil SE Bond Primer (10-methacryloyloxydecyl dihydrogen phosphate [10-MDP]) plus Clearfil porcelain bond activator (3-methacryloxypropyl-trimethoxy silane [3-MPS]) (CLE) or RelyX Ceramic Primer plus a layer of RelyX U100 adhesive-resin cement (REL). Composite resin cylinders were built on the Y-TZP treated surfaces. After thermocycling (6000 cycles, 5°C and 55°C, 30-second dwell time), an SBS test was carried out (n=14). Data were analyzed by 3-way ANOVA and the Tukey honest significant differences test (α=.05). The failure mode was analyzed., Results: The 3-way ANOVA was not significant for aging (P>.05), but the APA (P<.001), bonding agent (P<.001), and their interaction (P<.001) were significant. APA with ALU or ROC did not influence the SBS of the groups bonded with CLE, but the REL APA with ROC provided higher SBS. The failure mode was adhesive for all specimens., Conclusions: Adhesion was not different on monoclinic partially transformed Y-TZP. The APA with ROC followed by REL was the most effective treatment for repairing Y-TZP., (Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Background: The effect of alternative bearing materials on the risk of revision due to infection after total knee replacement remains uncertain. By reducing the immunomodulating polyethylene wear-particle burden and with different substrate bacterial adhesion properties, Oxinium oxidized zirconium and cross-linked polyethylene (XLPE) could alter infection risk. The purpose of the current study was to analyze the risk of revision for infection in 3 comparisons of bearing combinations., Methods: To evaluate the risk of revision for infection with XLPE, cobalt-chromium (CoCr) on XLPE was compared with CoCr on non-cross-linked polyethylene (NXLPE). To evaluate Oxinium, Oxinium-NXLPE was compared with CoCr-NXLPE, and to evaluate the possibility of an additional beneficial effect of Oxinium on XLPE, Oxinium-XLPE was compared with CoCr-XLPE. The cumulative percent revision (CPR) and hazard ratio (HR) for revision for infection in primary total knee replacement for osteoarthritis were determined from registry data from September 1, 1999, to December 31, 2015. Revisions within 6 months following the primary surgery were censored from the analysis, while procedures with posterior stabilized or fully stabilized total knee replacements as well as prostheses with a known higher risk of revision were excluded. Analyses were stratified by age, sex, and fixation type., Results: Of the 326,603 included primary total knee replacements, 1,511 (0.46%) were revised for infection. The risk of revision for infection was lower for CoCr-XLPE compared with CoCr-NXLPE (HR = 0.74; 95% confidence interval [CI] = 0.65 to 0.84; p < 0.001). This effect was apparent for both male and female patients overall, all fixation types, antibiotic cement use, those <65 years of age, and male patients ≥65 years of age. However, for female patients ≥65 years of age, there was no difference. Overall, Oxinium-NXLPE had the same revision risk as CoCr-NXLPE regardless of fixation; however, for cemented fixation, subanalysis showed a lower risk for Oxinium-NXLPE compared with CoCr-NXLPE (HR = 0.69; 95% CI = 0.51 to 0.94; p = 0.018). Oxinium-XLPE had the same revision risk for infection as CoCr-XLPE overall, among male patients, and when cemented fixation had been used., Conclusions: In this registry analysis, CoCr-XLPE had a 26% lower risk of revision for infection than CoCr-NXLPE, suggesting a reduction of wear particle-induced immunomodulation with XLPE. Oxinium-XLPE had the same risk as CoCr-XLPE. Overall, Oxinium did not reduce the infection risk., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Introduction: Literature on the potential release of trace elements following implantation of Zirconia-platelet toughened alumina (ZPTA) ceramic components is scant. The present study therefore analysed the in vitro and in vivo potential release of ions from ZPTA bearings., Material and Methods: An in vitro and in vivo study was conducted. The in vitro study compared leaching in bovine serum from two groups: ZPTA ceramic heads and Co-28Cr-6Mo alloy heads, both 28-mm diameter. A third group without implant served as reference group. An in vivo clinical study compared trace elements in the whole blood of patients with 36-mm diameter ZPTA ceramic-on-ceramic articulation after three and 12 months. A cohort of subjects without any prosthesis was used as control group. The release of ions was determined by high resolution-inductively coupled plasma-mass spectrometry., Results: In the in vitro experiment, significant differences (p ≤ 0.01) in trace element release for chromium, cobalt and molybdenum were found, with increased levels of ion release in the Co-28Cr-6Mo metal group. The very low detection limit for yttrium allowed detection of a small yttrium release from the ZPTA heads, which was not confirmed by the in vivo study. No significant difference between the groups was found for strontium, aluminium, and zirconium. In the in vivo study, no relevant differences in ion levels between the reference group without any implant and the study group were found at the three and 12-month follow-up., Conclusion: This study supports that ZPTA ceramic articulation components are safe in terms of ion release, and may be an excellent alternative to bearings based on Co-28Cr-6Mo alloys.

Objectives: To test the hypothesis that there is no difference in the in vivo maximum wear of enamel opposing monolithic zirconia crowns, enamel opposing porcelain fused to metal crowns and enamel opposing enamel., Methods: Thirty patients needing single crowns were randomized to receive either a monolithic zirconia or metal-ceramic crown. Two non-restored opposing teeth in the same quadrants were identified to serve as enamel controls. After cementation, quadrants were scanned for baseline data. Polyvinylsiloxane impressions were obtained and poured in white stone. Patients were recalled at six-months and one-year for re-impression. Stone models were scanned using a tabletop laserscanner to determine maximum wear. Statistical analysis was performed using Mann-Whitney U to determine any significant differences between the wear of enamel against zirconia and metal-ceramic crowns., Results: Sixteen zirconia and 14 metal-ceramic crowns were delivered. There were no statistical differences in mean wear of crown types (p=0.165); enamel antagonists (p=0.235) and enamel controls (p=0.843) after one year., Conclusion: Monolithic zirconia exhibited comparable wear of enamel compared with metal-ceramic crowns and control enamel after one year., Significance: This study is clinically significant because the use of polished monolithic zirconia demonstrated comparable wear of opposing enamel to metal-ceramic and enamel antagonists., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objectives: The aim of this 5-year randomized controlled trial was to compare the longevity and clinical behavior of single posterior crowns made with pressable ceramic on zirconia and on metal frameworks, and if failures occur, to delineate the contributing factors., Methods: 72 patients, who needed the covering of at least a molar and/or premolar, were included in the study. All teeth were endodontically treated, with absence of periapical lesion or active periodontitis. Ninety single crowns were made with zirconia or metal framework and covered with pressable veneering ceramics. Two independent examiners assessed the survival of restorations at 6 months, 1-4 and 5 years after restoration placement including periapical radiographs, intraoral photographs, and USPHS modified criteria. The statistical analyses were performed with the Kaplan-Meier method., Results: One core fracture occurred in Zircad/Zirpress crowns and one metal ceramic crown was lost for root fracture. Chipping fracture of the veneering ceramic was detected in 2 metal-ceramic crowns and in 3 zirconia-based crowns. The Estimate Cumulative Survival (ECS) and the Estimate Cumulative Success (ECSs) with standard deviation (SE) were respectively 97,73±2,19 and 92,64±4,14 for zirconia-based crowns whereas 97,44±2,39 and 91,11±4,27 for porcelain fused to metal crowns., Conclusions: The present randomized controlled trial shows that the survival of zirconia-based and metal-based single crowns is similar over a follow-up period of 5 years. No significant differences in esthetic, functional and biological outcomes were demonstrated between the two groups. The main failure mode was the chipping fracture of the veneering ceramic in both materials. Study number on ClinicalTrial.gov NCT02758457., Clinical Significance: According to the results of this clinical study, zirconia-based rehabilitations with overpressing veneering technique represent a valid alternative to metal-based for posterior single crown restorations., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: It is difficult to detect bone defects caused by loosening or osteolysis around the femoral component after total knee arthroplasty (TKA) because the thick metal hinders visualization of bone defects. Previous reports have shown that tomosynthesis, a novel tomographic technique, is advantageous over fluoroscopically guided plain radiography, computed tomography (CT) and magnetic resonance imaging (MRI) for the early detection of bone defects around a conventional cobalt-chromium alloy component. However, there have been no reports on a zirconium component. The purpose of this study was to examine the sensitivity and specificity of the detection of bone defects around a zirconium component using fluoroscopically guided plain radiography, tomosynthesis, CT and MRI., Methods: Six zirconium femoral components were implanted in pig knees. Two were cemented without any bone defects. Two were cemented with cystic defects. Two were cemented with four-millimeter-thick defects between the bone cement and the bone. Defects were filled with agarose gel. Eight orthopedic surgeons examined the fluoroscopically guided plain radiography, tomosynthesis, CT and MRI images. Sensitivity and specificity of each method were analyzed., Results: No bone defects were detected with plain radiography. The sensitivity and specificity of tomosynthesis were 21.9% and 36.8%, respectively. The sensitivity and specificity of CT were 15.1% and 33.0%, respectively. The sensitivity and specificity of MRI were 84.4% and 86.6%, respectively., Conclusions: For the detection of bone defects around a zirconium component after TKA, MRI is advantageous over fluoroscopically guided plain radiography, tomography and CT, in terms of sensitivity and specificity., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Statement of Problem: Abutments with a zirconia superstructure and a titanium insert have recently become popular. Although they have been tested under static load, their performance under simulated mastication is not well known., Purpose: The purpose of this in vitro study was to compare the cyclic load to failure of 3 types of zirconia abutments with different mechanisms of retention of the zirconia to the titanium interface., Material and Methods: Fifteen implants (n=5 per system) and abutments (3 groups: 5 friction fit [Frft]; 5 bonded; and 5 titanium ring friction fit [Ringfrft]) were used. Abutments were thermocycled in water between 5°C and 55°C for 15000 cycles and then cyclically loaded for 20000 cycles or until failure at a frequency of 2 Hz by using a sequentially increased loading protocol up to a maximum of 720 N. The load to failure for each group was recorded, and 1-way analysis of variance was performed., Results: The mean load-to-failure values for the Frft group was 526 N, for the Bond group 605 N, and for the Ringfrft group 288 N. A statistically significant difference was found among all abutments tested (P<.05)., Conclusions: Abutments with the bonded connection showed the highest load-to-failure value, and the abutment with the titanium ring friction fit connection showed the lowest load-to-failure value., (Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

To determine the survival rate and marginal bone loss (MBL) of zirconia dental implants restored with single crowns or fixed dental prostheses. An electronic search was conducted up to November 2015 (without any restriction regarding the publication time) through the databases MEDLINE (PubMed), Cochrane Library, and EMBASE to identify randomized controlled clinical trials and prospective clinical trials including >15 patients. Primary outcomes were survival rate and MBL. Furthermore, the influence of several covariates on MBL was evaluated. Qualitative assessment and statistical analyses were performed. This review was conducted according to preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines for systematic reviews. With the applied search strategy, 4,196 titles could be identified. After a screening procedure, 2 randomized controlled clinical trials and 7 prospective clinical trials remained for analyses. In these trials, a total of 326 patients received 398 implants. The follow-up ranged from 12 to 60 mo. Implant loss was mostly reported within the first year, especially within the healing period. Thereafter, nearly constant survival curves could be observed. Therefore, separate meta-analyses were performed for the first and subsequent years, resulting in an implant survival rate of 95.6% (95% confidence interval: 93.3% to 97.9%) after 12 mo and, thereafter, an expected decrease of 0.05% per year (0.25% after 5 y). Additionally, a meta-analysis was conducted for the mean MBL after 12 mo, resulting in 0.79 mm (95% confidence interval: 0.73 to 0.86 mm). Implant bulk material and design, restoration type, and the application of minor augmentation procedures during surgery, as well as the modes of temporization and loading, had no statistically significant influence on MBL. The short-term cumulative survival rates and the MBL of zirconia implants in the presented systematic review are promising. However, additional data are still needed to confirm the long-term predictability of these implants.

Nickel (Ni) eluted from metallic biomaterials is widely accepted as a major cause of allergies and inflammation. To improve the safety of cobalt-chromium-molybdenum (Co-Cr-Mo) alloy implants, new ultralow-Ni Co-Cr-Mo alloys with and without zirconium (Zr) have been developed, with Ni contents of less than 0.01%. In the present study, we investigated the biocompatibility of these new alloys in vivo by subcutaneously implanting pure Ni, conventional Co-Cr-Mo, ultralow-Ni Co-Cr-Mo, and ultralow-Ni Co-Cr-Mo with Zr wires into the dorsal sides of mice. After 3 and 7 days, tissues around the wire were excised, and inflammation; the expression of IL-1β, IL-6, and TNF-α; and Ni, Co, Cr, and Mo ion release were analyzed using histological analyses, qRT-PCR, and inductively coupled plasma mass spectrometry (ICP-MS), respectively. Significantly larger amounts of Ni eluted from pure Ni wires than from the other wires, and the degree of inflammation depended on the amount of eluted Ni. Although no significant differences in inflammatory reactions were identified among new alloys and conventional Co-Cr-Mo alloys in histological and qRT-PCR analyses, ICP-MS analysis revealed that Ni ion elution from ultralow-Ni Co-Cr-Mo alloys with and without Zr was significantly lower than from conventional Co-Cr-Mo alloys. Our study, suggests that the present ultralow-Ni Co-Cr-Mo alloys with and without Zr have greater safety and utility than conventional Co-Cr-Mo alloys. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1505-1513, 2016., (© 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

The purpose of this study was to measure enamel wear caused by antagonistic monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia full molar crowns were placed in 20 patients. Patients with high activity of the masseter muscle at night (bruxism) were excluded. For analysis of wear, vinylpolysiloxane impressions were prepared after crown incorporation and at 6-, 12-, and 24-month follow-up. Wear of the occlusal contact areas of the crowns, of their natural antagonists, and of two contralateral natural antagonists (control teeth) was measured by use of plaster replicas and a 3D laser-scanning device. Differences of wear between the zirconia crown antagonists and the control teeth were investigated by means of two-sided paired Student's t-tests and linear regression analysis. After 2 years, mean vertical loss was 46 μm for enamel opposed to zirconia, 19-26 μm for contralateral control teeth and 14 μm for zirconia crowns. Maximum vertical loss was 151 μm for enamel opposed to zirconia, 75-115 μm for control teeth and 60 μm for zirconia crowns. Statistical analysis revealed significant differences between wear of enamel by zirconia-opposed teeth and by control teeth. Gender, which significantly affected wear, was identified as a possible confounder. Monolithic zirconia crowns generated more wear of opposed enamel than did natural teeth. Because of the greater wear caused by other dental ceramics, the use of monolithic zirconia crowns may be justified., (© 2016 John Wiley & Sons Ltd.)

Objective: To investigate the health status of workers exposed to zircon sand and silica dust in a precision casting enterprise, and to provide a basis for the development of prevention and control measures. Methods: Occupational health examination, questionnaire survey, and field investigation of occupational health were performed for 176 male workers (18 workers in the zirconium dust exposure group, 109 in the non-zirconium dust exposure group, and 49 in the non-dust exposure group) in a precision casting enterprise, and a statistical analysis was performed for the data obtained. Results: Dust and noise were major hazard factors for occupational diseases in this enterprise. The abnormal rate of physical examination was 71.02%. Compared with the non-zirconium dust exposure group, the zirconium dust exposure group had significantly higher detection rates of restrictive ventilatory dysfunction, increased immunoglobulin IgE, increased alanine aminotransferase, and increased alkaline phosphatase (ALP) ( P <0.05) ; compared with the non-dust exposure group, the zirconium dust exposure group had a significantly higher detection rate of increased ALP ( P <0.05) . Of all workers, 15 were found to have pneumoconiosis-like changes (11 had pneumoconiosis and 4 needed observation) , among whom 4 were in the zirconium dust exposure group (3 had pneumoconiosis and 1 needed observation) and 11 were in the non-zirconium dust exposure group (8 had pneumoconiosis and 3 needed observation) . The detection rate of pneumoconiosis-like changes showed no significant differences between the two groups (20.22% vs 10.09%) . Conclusions: There was a severe dust hazard in this enterprise. Inhalation of dust containing zirconium is associated with respiratory system injury, especially the development of pneumoconiosis, and it may also cause immune dysfunction and liver impairment.

This practice-based study evaluates the survival and success of conventionally luted metal-ceramic and zirconia molar crowns fabricated by using a prolonged cooling period for the veneering porcelain. Fifty-three patients were treated from 07/2008 to 07/2009 with either metal-ceramic crowns (MCC) or zirconia crowns (ZC). Forty-five patients (26 female) with 91 restorations (obser-vational period: 64.0 ± 4.8 months) participated in a clinical follow-up examination and were included in the study. Estimated cumulative survival (ECSv), success (ECSc) and veneering ceramic success (ECVCSc) were calculated (Kaplan-Meier) and analysed by the crown fabrication technique and the position of the restoration (Cox regression model) (P < 0.05). Five complete failures (MCC: 2, ZC: 3) were recorded (5-year ECSv: MCC: 97.6%, (95% confidence interval (95%-CI): [93%; 100%]/ZC: 94.0%, (95%-CI): [87%; 100%]). Of the MCCs (n = 41), 85.0%, [95%-CI: (77%; 96%)] remained event-free, whereas the ECSc for the ZCs (n = 50) was 74.3% (95%-CI): [61%; 87%]. No significant differences in ECSv (P = 0.51), ECSc (P = 0.43) and ECVCSc (P = 0.36) were detected between the two fabrication techniques. Restorations placed on terminal abutments (n = 44) demonstrated a significantly lower ECVCSc (P = 0.035), (5-year VCF-rate: 14.8%) than crowns placed on tooth-neighboured abutments (n = 47), (5-year VCF-rate: 4.3%). In the present study, zirconia molar crowns demonstrated a 5-year ECSv, ECSc and ECVCSc comparable to MCCs. Irrespective of the fabrication technique, crowns on terminal abutments bear a significantly increased risk for VCFs. Clinical investigations with an increased number of restorations are needed., (© 2015 John Wiley & Sons Ltd.)

The aim of the present study was to assess the discoloration of the peri-implant mucosa caused by zirconia (Zr) and titanium (Ti) dental implants with and without soft tissue grafting (STG). Zr and Ti implants were inserted in edentulous areas in pig maxillae. Spectrophotometric measurements were performed prior to and after the insertion of the implants, and following the placement of a STG on the buccal side. A significant discoloration of the mucosa was observed with a mean ΔE of 8.05 (± 2.51) (Ti) and 4.93 (± 3.18) (Zr). In conjunction with a STG, ΔE values amounted to 5.31 ± 3.50 (Ti) and 5.95 (± 3.68) (Zr). The placement of Zr implants led to less discoloration of the mucosa than Ti implants without STG.

The use of alternative bearing surfaces for total hip arthroplasty has become popular to minimize wear and increase longevity, especially in young patients. Oxidized zirconium (Oxinium; Smith & Nephew, Memphis, Tennessee) femoral heads were introduced in the past decade for use in total hip arthroplasty. The advantages of oxidized zirconium include less risk of fracture compared with traditional ceramic heads. This case report describes a patient with a history of bilateral avascular necrosis of the femoral head after chemotherapy for acute lymphoblastic leukemia. Nonoperative management of avascular necrosis failed, and the patient was treated with bilateral total hip arthroplasty. The patient was followed at regular intervals and had slow eccentric polyethylene wear during a 10-year period. After 10 years, the patient had accelerated wear, with femoral and acetabular bone changes as a result of Oxinium and ultrahigh-molecular-weight polyethylene wear during a 6-month period. This article highlights the unusual accelerated bone changes that occurred as a result of Oxinium wear particles., (Copyright 2016, SLACK Incorporated.)

The purpose of this randomized controlled study is to investigate the clinical results obtained over four years and incidence of complications associated with one- versus two-piece custom made zirconia anchorages, in single tooth implant-supported restorations of the maxillary anterior region. Sixty-five patients, with a total of 74 missing maxillary teeth, were selected in the period from February 2007 to July 2010. Two different ways of custom made zirconia abutment and final prosthetic restoration were evaluated: a standard zirconia abutment associated with a pressed layer of lithium disilicate with an all-ceramic cemented restoration versus one-piece restoration with the facing porcelain fired and pressed straight to the custom made zirconia abutment. In 29 cases, the restoration consisted of an all-ceramic restoration for cementation (two pieces); in 45 cases the restoration was a screw-retained restoration (one piece). Three all-ceramic restorations broke during the observation time. Two one-piece restorations fractured after 26 months. At follow-up examination there were no significant differences between one-piece and two-piece groups regarding the PI, BI, and MBL. Awaiting studies with longer follow-up times, a careful conclusion is that zirconia anchorages for single-implant restorations seem to demonstrate good short-term technical and biological results.

Background: Against the background of increasing use of dental implants, and thus an increasing prevalence of implant-associated complications, a deeper understanding of the biomolecular mechanisms in the peri-implant tissue is needed. Peri-implant soft tissue is in direct contact with transmucosal dental implant abutments. The aim of this trial is to distinguish the biomolecular and histological interactions of various dental abutment materials with peri-implant soft tissue., Methods/design: The study is designed as a prospective, randomized, investigator-initiated clinical pilot trial with blinded assessment. We will ultimately include 24 eligible patients who opt for implant treatment to replace a single missing posterior tooth. Three months after implantation (submerged procedure), the study begins with the second-stage surgery. Each of the 24 patients will be given three different transmucosal abutments (zirconia, lithium disilicate, titanium) consecutively. The sequence in which the three materials are used is randomized. Peri-implant crevicular fluid is sampled weekly around the respective abutment for biomolecular analyses. After one month of wearing time, the stamping press from the second-stage surgery is used to gain a narrow gingival ring biopsy around the abutment for immunohistochemical analyses. The next abutment is then inserted. The same procedure is used for all three abutments. After sampling is completed, the patients will receive a definitive crown. The primary outcome measure of the trial is biomolecular detection of specific markers in the peri-implant crevicular fluid: matrix metalloproteinase 8, interleukin- 1β, polymorphonuclear elastase, and myeloid-related protein MRP8/14 (calprotectin). Secondary outcome measures include immunohistochemical analyses and clinical parameters., Discussion: The study design will allow us to perform correlation analyses between the clinical indices with biomarkers' expression in the interface of the transmucosal abutments and the peri-implant soft tissue. A deeper understanding of the three abutment materials' interactions with peri-implant soft tissue will help us understand the formation mechanisms of implant-associated complications and then develop prevention strategies., Trial Registration: The trial is registered at the German Clinical Trial Register and the International Clinical Trials Registry Platform by the WHO under DRKS00006555 (Registered on 27 October 2014).

Aim: To investigate the effect of laboratory and clinical finishing procedures for zirconia on antagonistic enamel wear., Materials and Methods: Forty-eight yttria-tetragonal partially stabilised zirconia (Y-TZP) specimens were prepared and divided into four groups according to their surface preparation: laboratory polished (LP); laboratory polished and glazed (G); clinically adjusted (CA); and clinically adjusted and repolished (CAR). Enamel opposing enamel was used as a control. Pre-testing surface roughness for each group was determined using contact profilometry. Two-body wear resistance tests were conducted using a masticatory simulator. Enamel specimens were subjected to 120,000 cycles in distilled water (frequency 1.6 Hz, loading force of 49 N). Volumetric and vertical enamel losses were measured by superimposition of pre- and post-testing images using a three-dimensional laser scanner and software analysis. Scanning electron microscopy was used for qualitative surface analysis of pre- and post-testing zirconia and enamel surfaces. One-way ANOVA and multiple comparisons with Bonferroni corrections were used for statistical analysis at a significance level of α=0.05., Results: There was no statistical difference in volumetric and vertical enamel loss between CAR, G and LP. CAR produced statistically significantly less volumetric enamel loss compared with CA and control, and statistically significantly less vertical enamel loss compared with CA. Volumetric and vertical enamel loss were highly correlated in all groups., Conclusions: Enamel wear by clinically ground zirconia is comparable to that of opposing enamel surfaces and greater than clinically repolished zirconia. Repolishing of zirconia restorations following clinical adjustment with diamond burs is effective in reducing antagonistic enamel wear., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Microleakage through the interface has been documented in implant systems with titanium (Ti) abutments. There is a current increase in the use of zirconia (Zi) abutments especially in esthetic zone in where higher risk of visible metal color through the peri-implant tissues exists., Purpose: The aim of the present in vitro study is to evaluate the leakage at the implant fixture-abutment interface with two different screw-retained abutment systems at different torque values in a nonloading condition., Materials and Methods: In vitro study design included four groups (Ti and Zi torqued at 25 and 15 Ncm [N = 8/group]). Microcomputed tomography (micro-CT) was chosen to detect microgap. Microleakage from the implant chamber to the external milieu was evaluated using limulus amebocyte lysate (LAL) test, while microleakage from external milieu to the implant chamber was evaluated using toluidine blue dye (TBD) and colorimeter., Results: Micro-CT images did not reveal any microgap. LAL test showed that there is a time-, abutment-, and torque-dependent increase in microleakage (p = .001) with Zi torqued at 15 Ncm having higher leakage with time compared with Ti torqued at 15 Ncm (p = .002), as well as Zi torqued at 15 Ncm having higher leakage with time compared with Zi torqued at 25 Ncm (p = .01). TBD test showed a nonsignificant increase in microleakage with higher leakage related to titanium abutment groups (p > .05). Repeated torque/antitorque handling differentially affected microleakage (p = .01)., Conclusions: Within the limits of this study, there is a statistically significant difference in bidirectional microleakage with time, abutment type, and torque values being major players for leakage from internal implant chamber to external milieu, while the abutment type and time but not the torque value being important factors for leakage from external milieu into implant chamber in nonloading condition. Future studies are needed to determine peri-implant health around Zi abutments., (© 2015 Wiley Periodicals, Inc.)

Aim: The objective of this review was to analyze research with regard to the effect of zirconia or titanium as abutment material on soft peri-implant tissues., Methods: Clinical studies were selected via electronic and hand searches in English language journals until December 1, 2014. Only randomized clinical trials (RCTs) and prospective controlled clinical trials (CCTs) showing direct comparison between zirconia (Zr) and titanium (Ti) abutments in the same patient were considered. The outcome measures were (1) soft tissue color, (2) soft tissue recession, (3) peri-implant probing, (4) bleeding on probing, (5) esthetic indexes, (6) patient-reported outcome, (7) marginal bone level, and (8) biological complications., Results: Nine relevant studies (11 papers) were identified: 4 RCTs and 5 CCTs. Due to heterogeneity in the study design, statistical methods, and reported results, a meta-analysis of the data was feasible only for soft tissue color. The outcome was found to be significantly superior for Zr abutments. For the other outcome measures, a qualitative analysis of the selected articles was performed. The studies did not show any statistically significant differences between Zr and Ti abutments on soft tissue recession, probing depths, bleeding on probing, marginal bone level, and patient-reported outcome. One study reported significantly higher pink esthetic score (PES) scores at Zr implants with Zr abutments, compared to metal implants and Ti abutments., Conclusion: Overall, the research does not support any obvious advantage of Ti or Zr abutments over each other. However, there is a significant tendency in Zr abutments evoking better color response of peri-implant mucosa and superior esthetic outcome measured by PES score., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Statement of Problem: Tooth wear is a complex process, which, if not prevented, may adversely affect the integrity of the stomatognathic system. Different restorative dental materials may affect the amount of wear on natural enamel antagonists., Purpose: The purpose of this in vivo study was to evaluate and compare the wear of enamel opposing natural enamel, zirconia, and metal ceramic crowns after 1 year., Material and Methods: Ten participants between 18 and 35 years of age requiring 2 complete crowns, 1 on either side of maxillary or mandibular molar region, and having healthy natural teeth in the opposing arch were selected. For each participant, 1 monolithic polished zirconia crown and 1 glazed metal ceramic crown were fabricated and cemented. To evaluate the wear of the antagonistic natural enamel (premolar and molar), polyvinyl siloxane impressions were made immediately (baseline) and at 1 year after cementation. The wear of natural enamel against natural enamel was evaluated as the control. The resulting casts were scanned (using a 3D white light scanner), and 3D software was used to calculate the maximum amount of linear wear., Results: One-way repeated measures ANOVA was conducted to analyze data. Mean ±SD occlusal wear of the antagonistic enamel 1 year after the cementation of metal ceramic crowns was 69.20 ±4.10 μm for premolar teeth and 179.70 ±8.09 μm for molar teeth, whereas for zirconia crowns, it was 42.10 ±4.30 μm for premolar teeth and 127.00 ±5.03 μm for molar teeth. Occlusal wear of natural enamel opposing natural enamel was 17.30 ±1.88 μm in the premolar region and 35.10 ±2.60 μm in the molar region. The Bonferroni post hoc test revealed that the occlusal wear of antagonistic enamel 1 year after the cementation of a metal ceramic crown was significantly higher (P<.001) than that of an opposing zirconia crown or natural enamel., Conclusions: Zirconia crowns led to less wear of antagonist enamel than metal ceramic crowns, but more than natural enamel., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Introduction: Mineral trioxide aggregate (MTA) materials have been used for many years as a pulp therapy material. The most widely used product, ProRoot MTA (Dentsply, Tulsa, OK), has a major drawback in that it causes tooth discoloration. Alternatives have recently been developed such as ENDOCEM Zr (MARUCHI, Wonju, Korea) and RetroMTA (BioMTA, Seoul, Korea). The purpose of this study was to compare the discoloration of these various MTA-based materials., Methods: Discoloration of discs prepared from 4 different MTA-based materials (ProRoot MTA, MTA Angelus [Angelus, Londrina, PR, Brazil], ENDOCEM Zr, and RetroMTA) were observed at 15 and 30 minutes after exposure to light at an intensity of 1000 mA/cm(2). In a tooth model, 12 premolars were used per each group to retrofill the pulp chamber with MTA-based materials. The degree of discoloration was measured over a 16-week period using a digital spectrophotometer., Results: Distinct color changes were observed for discs made from ProRoot MTA and MTA Angelus, but no clear change was observed for those made from either ENDOCEM Zr or RetroMTA. In the tooth model, more distinct, time-dependent color changes were observed for teeth filled with ProRoot MTA and MTA Angelus than for those filled with ENDOCEM Zr and RetroMTA., Conclusions: Less discoloration was observed with ENDOCEM Zr and RetroMTA (which contain zirconium oxide) than with ProRoot MTA and MTA Angelus (which contain bismuth oxide) in both of the test models used., (Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Zirconia is often used for implant abutments for esthetics. The aim of this clinical study was to compare the effects of zirconia and metal abutments on periimplant soft tissue., Materials and Methods: Ten maxillary anterior implant patients, 5 with metal abutments and 5 with zirconia abutments, were enrolled in this trial. The soft tissue around the implant abutments was evaluated by 2-dimensional laser speckle imaging and thermography. The blood flow in soft tissue around natural teeth was also measured to correct for differences among the subjects., Results: Significantly greater blood flow was detected in the zirconia abutment group (95.64 ± 5.17%) relative to the metal abutment group (82.25 ± 8.92%) in free gingiva (P = 0.0317). Reduced blood flow (by almost 18%) was detected in the tissue surrounding metal abutments compared with the tissue surrounding natural teeth. The surface temperature showed no significant difference for all measurements., Conclusions: These results suggest that blood flow in tissue surrounding zirconia abutments is similar to that in soft tissue around natural teeth. Moreover, zirconia abutments could be advantageous for the maintenance of immune function by improving blood circulation.

Purpose: (111)In (typically as [(111)In]oxinate3) is a gold standard radiolabel for cell tracking in humans by scintigraphy. A long half-life positron-emitting radiolabel to serve the same purpose using positron emission tomography (PET) has long been sought. We aimed to develop an (89)Zr PET tracer for cell labelling and compare it with [(111)In]oxinate3 single photon emission computed tomography (SPECT)., Methods: [(89)Zr]Oxinate4 was synthesised and its uptake and efflux were measured in vitro in three cell lines and in human leukocytes. The in vivo biodistribution of eGFP-5T33 murine myeloma cells labelled using [(89)Zr]oxinate4 or [(111)In]oxinate3 was monitored for up to 14 days. (89)Zr retention by living radiolabelled eGFP-positive cells in vivo was monitored by FACS sorting of liver, spleen and bone marrow cells followed by gamma counting., Results: Zr labelling was effective in all cell types with yields comparable with (111)In labelling. Retention of (89)Zr in cells in vitro after 24 h was significantly better (range 71 to >90%) than (111)In (43-52%). eGFP-5T33 cells in vivo showed the same early biodistribution whether labelled with (111)In or (89)Zr (initial pulmonary accumulation followed by migration to liver, spleen and bone marrow), but later translocation of radioactivity to kidneys was much greater for (111)In. In liver, spleen and bone marrow at least 92% of (89)Zr remained associated with eGFP-positive cells after 7 days in vivo., Conclusion: [(89)Zr]Oxinate4 offers a potential solution to the emerging need for a long half-life PET tracer for cell tracking in vivo and deserves further evaluation of its effects on survival and behaviour of different cell types.

Objectives: This prospective clinical study compared the performance of implant-retained (study group) and tooth-retained (control) zirconia based fixed dental prostheses (FDPs) with at least 4 units. The null-hypothesis stated that complication rates in both groups are equally distributed., Methods: The study included patients in need of one 4- to 6-unit implant- or tooth-retained FDP each. All patients were examined 2 weeks after insertion (baseline) and then at 6 month intervals up to 3 years. At follow-up all restorations were examined for framework fracture, chipping, marginal integrity, surface roughness and biological complications. Kaplan-Meier estimation was used for data analysis., Results: 20 patients received tooth-retained and 7 patients implant-retained FDPs. The study was halted early when differences in chipping rates reached a statistically significant level. One FDP in the study group was lost due to implant abutment failure. FDP related chipping rates were 71% in the study group (mean observation time 32 months) and 15% in the control (mean observation time 34 months). Unit (abutment crown/pontic) related chipping rates were 32% in the study group and 6% in the control. Chipping rates differed statistically significant (log-rank test, p<.05). However, all ceramic defects could be corrected by grinding and polishing. No framework fracture was detected., Conclusions: Within the study limitations, survival rates seem satisfactorily in both implant- and tooth retained long-span zirconia based FDPs. However, implant-supported FDPs seem more susceptible to veneering ceramic chippings., Clinical Significance: The high chipping rates found in this study discourage the use of long-span implant-retained FDPs with zirconia frameworks. The study was registered in ClinicalTrials.gov with the ID Number NCT02220764., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The aim of this study was to assess hard and soft tissue responses using three dental implants made of different materials. Implants made of titanium (Ti), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria partially stabilized zirconia/alumina nanocomposite (Ce-TZP/Al2O3) were used in a dog model. Five male beagles were sacrificed at three months after implantation, and harvested mandible were observed and analyzed. Histological observations were similar in all groups. There were no significant differences in any histomorphometric parameters. Our results suggested the possibility of Ce-TZP/Al2O3 as a dental implant material, similar to Ti and Y-TZP.

Importance: Hyperkalemia is a common electrolyte abnormality that may be difficult to manage because of a lack of effective therapies. Sodium zirconium cyclosilicate is a nonabsorbed cation exchanger that selectively binds potassium in the intestine., Objective: To evaluate the efficacy and safety of zirconium cyclosilicate for 28 days in patients with hyperkalemia., Design, Setting, and Participants: HARMONIZE was a phase 3, multicenter, randomized, double-blind, placebo-controlled trial evaluating zirconium cyclosilicate in outpatients with hyperkalemia (serum potassium ≥5.1 mEq/L) recruited from 44 sites in the United States, Australia, and South Africa (March-August 2014)., Interventions: Patients (n = 258) received 10 g of zirconium cyclosilicate 3 times daily in the initial 48-hour open-label phase. Patients (n = 237) achieving normokalemia (3.5-5.0 mEq/L) were then randomized to receive zirconium cyclosilicate, 5 g (n = 45 patients), 10 g (n = 51), or 15 g (n = 56), or placebo (n = 85) daily for 28 days., Main Outcomes and Measures: The primary end point was mean serum potassium level in each zirconium cyclosilicate group vs placebo during days 8-29 of the randomized phase., Results: In the open-label phase, serum potassium levels declined from 5.6 mEq/L at baseline to 4.5 mEq/L at 48 hours. Median time to normalization was 2.2 hours, with 84% of patients (95% CI, 79%-88%) achieving normokalemia by 24 hours and 98% (95% CI, 96%-99%) by 48 hours. In the randomized phase, serum potassium was significantly lower during days 8-29 with all 3 zirconium cyclosilicate doses vs placebo (4.8 mEq/L [95% CI, 4.6-4.9], 4.5 mEq/L [95% CI, 4.4-4.6], and 4.4 mEq/L [95% CI, 4.3-4.5] for 5 g, 10 g, and 15 g; 5.1 mEq/L [95% CI, 5.0-5.2] for placebo; P < .001 for all comparisons). The proportion of patients with mean potassium <5.1 mEq/L during days 8-29 was significantly higher in all zirconium cyclosilicate groups vs placebo (36/45 [80%], 45/50 [90%], and 51/54 [94%] for the 5-g, 10-g, and 15-g groups, vs 38/82 [46%] with placebo; P < .001 for each dose vs placebo). Adverse events were comparable between zirconium cyclosilicate and placebo, although edema was more common in the 15-g group (edema incidence: 2/85 [2%], 1/45 [2%], 3/51 [6%], and 8/56 [14%] patients in the placebo, 5-g, 10-g, and 15-g groups). Hypokalemia developed in 5/51 (10%) and 6/56 patients (11%) in the 10-g and 15-g zirconium cyclosilicate groups, vs none in the 5-g or placebo groups., Conclusions and Relevance: Among outpatients with hyperkalemia, open-label sodium zirconium cyclosilicate reduced serum potassium to normal levels within 48 hours; compared with placebo, all 3 doses of zirconium cyclosilicate resulted in lower potassium levels and a higher proportion of patients with normal potassium levels for up to 28 days. Further studies are needed to evaluate the efficacy and safety of zirconium cyclosilicate beyond 4 weeks and to assess long-term clinical outcomes., Trial Registration: clinicaltrials.gov Identifier: NCT02088073.

Worn particulate titanium abraded from a titanium dental implant that discolors the adjacent soft tissues has not previously been reported. Two cases of this gingival tissue "tattooing" are reported here. While the use of zirconia abutments in areas of high esthetic concern is widespread, the effects of particulate titanium being worn from the implant by the much harder abutment material and then taken up in the adjacent soft tissues should be considered as a potential complication and a consideration when selecting the type of abutment to be used.

The purpose of this study was to evaluate enamel wear caused by monolithic zirconia crowns and to compare this with enamel wear caused by contralateral natural antagonists. Twenty monolithic zirconia crowns were placed in 20 patients requiring full molar crowns. For measurement of wear, impressions of both jaws were made at baseline after crown cementation and at 6-month follow-up. Mean and maximum wear of the occlusal contact areas of the crowns, of their natural antagonists and of the two contralateral natural antagonists were measured by the use of plaster replicas and 3D laser scanning methods. Wear differences were investigated by the use of two-sided paired Student's t-tests and by linear regression analysis. Mean vertical loss (maximum vertical loss in parentheses) was 10 (43) μm for the zirconia crowns, 33 (112) μm for the opposing enamel, 10 (58) μm for the contralateral teeth and 10 (46) μm for the contralateral antagonists. Both mean and maximum enamel wear were significantly different between the antagonists of the zirconia crowns and the contralateral antagonists. Gender and activity of the masseter muscle at night (bruxism) were identified as possible confounders which significantly affected wear. Under clinical conditions, monolithic zirconia crowns seem to be associated with more wear of opposed enamel than are natural teeth. With regard to wear behaviour, clinical application of monolithic zirconia crowns is justifiable because the amount of antagonistic enamel wear after 6 months is comparable with, or even lower than, that caused by other ceramic materials in previous studies., (© 2014 John Wiley & Sons Ltd.)

Zr-based bulk metallic glasses (BMG) show high corrosion resistance in vitro and higher strength and lower Young's modulus than crystalline alloys with the similar composition. This study aimed to perform an in vivo evaluation of Zr65Al7.5Ni10Cu17.5 BMG. Osteotomy of the femur was done in rats and stabilized with intramedullary nails made of Zr65Al7.5Ni10Cu17.5 BMG, Ti-6Al-4V alloy, or 316L stainless steel. Systemic and local effects of each type of nail were evaluated by measuring the levels of Cu and Ni in the blood and the surrounding soft tissue. Changes of the surface of each nail were examined by scanning electron microscopy (SEM). Healing of the osteotomy was evaluated by peripheral quantitative computed tomography and mechanical testing. No increase of Cu and Ni levels was recognized. Surface of the BMG showed no noticeable change, while Ti-6Al-4V alloy showed Ca and P deposition and 316L stainless steel showed surface irregularities and pitting by SEM observation. The stress strain index, maximum torque, torsional stiffness, and energy absorption values were larger for the BMG than those for Ti-6Al-4V alloy, although there was no significant difference. The Zr-based BMG can promote osteotomy healing as fast as Ti-6Al-4V alloy, with the possible advantage of the Zr-based BMG that bone bonding is less likely, allowing easier nail removal compared with Ti-6Al-4V alloy. The Zr-based BMG is promising for the use in osteosynthetic devices that are eventually removed.

Purpose: We evaluated the risk of hypersensitivity to metals in a population of consecutive subjects undergoing a total knee arthroplasty (TKA). We also proposed a diagnostic pathway to address any sensitivity to metals. We finally presented the mid-term outcomes of a full non allergenic knee implant., Methods: We developed a protocol based on the medical history, patch testing, and on specific laboratory assays, in order to assess a sensitization to metals. Twenty-four patients (25 knees) with referred or suspected allergy to metals were found in more than 1,000 treated patients, with a mean age of 72.9 years. We proceeded to a radiologic study, a clinical evaluation by the visual analogic scale (VAS), and Knee Society rating system (KSS). In all cases a full anallergic cemented implant with an oxidized zirconium femoral component and an all-polyethylene tibial baseplate was chosen., Results: Four (16.6%) of the 24 patients were considered to be hypersensitive to metals. The mean follow-up was 79.2 months. No patient reported any reaction related to hypersensitivity or complications after TKA. The VAS improved from a mean preoperative value of 7.2 to 1.8 postoperatively; the KSS and the functional score increased from 38 to 91 points and from 39 to 88 points, respectively., Conclusions: We consider careful research of medical history for metals hypersensitivity crucial, and we perform patch testing and lab assays in case of doubtful sensitization. The choice of a modern hypoallergenic implant may prevent any kind of potential reactions.