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Objective: To compare the clinical outcomes between ceramic-on-ceramic (CoC) and ceramic-on-polyethylene (CoP) bearing surfaces in patients undergoing total hip arthroplasty (THA) through a pooled analysis and evidence update., Methods: We performed a systematic literature search using PubMed, Embase, Cochrane Library and Web of Science up to March 2023 for studies that compared the bearing surfaces of CoC and CoP in patients undergoing THA. The primary outcomes were the incidence of common postoperative complications and the rate of postoperative revision. The secondary outcome was the Harris Hip Score., Results: A total of 10 eligible studies involving 1,946 patients (1.192 CoC-THA versus 906 CoP-THA) were included in the evidence synthesis. Pooled analysis showed no significant difference in the rates of common postoperative complications (dislocation, deep vein thrombosis, infection, wear debris or osteolysis) and of revision. After eliminating heterogeneity, the postoperative Harris Hip Score was higher in the CoC group than in the CoP group. However, the strength of evidence was moderate for the Harris Hip Score., Conclusion: CoC articulations are more commonly used in younger, healthier, and more active patients. While the performance of conventional polyethylene is indeed inferior to highly cross-linked polyethylene, there is currently a lack of sufficient research comparing the outcomes between highly cross-linked polyethylene and CoC bearing surfaces. This area should be a focal point for future research, and it is hoped that more relevant articles will emerge. Given the limited number of studies included, the heterogeneity and potential bias of those included in the analysis, orthopaedic surgeons should select a THA material based on their experience and patient-specific factors, and large multicentre clinical trials with >15 years of follow-up are needed to provide more evidence on the optimal bearing surface for initial THA., Competing Interests: The authors declare there are no competing interests., (©2024 Wu et al.)

In this research we subjected samples of poly(L-lactide) (PLLA) extruded film to ultraviolet (193 nm ArF excimer laser) radiation below the ablation threshold. The modified film was immersed in Simulated Body Fluid (SBF) at 37 °C for 1 day or 7 days to obtain a layer of apatite ceramic (CaP) coating on the modified PLLA surface. The samples were characterized by means of optical profilometry, which indicated an increase in average roughness (Ra) from 25 nm for the unmodified PLLA to over 580 nm for irradiated PLLA incubated in SBF for 1 day. At the same time, the water contact angle decreased from 78° for neat PLLA to 35° for irradiated PLLA incubated in SBF, which suggests its higher hydrophilicity. The obtained materials were investigated by means of cell response fibroblasts (3T3) and macrophage-like cells (RAW 264.7). Properties of the obtained composites were compared to the unmodified PLLA film as well as to the UV-laser irradiated PLLA. The activation of the PLLA surface by laser irradiation led to a distinct increase in cytotoxicity, while the treatment with SBF and the deposition of apatite ceramic had only a limited preventive effect on this harmful impact and depended on the cell type. Fibroblasts were found to have good tolerance for the irradiated and ceramic-covered PLLA, but macrophages seem to interact with the substrate leading to the release of cytotoxic products.

Methods: The current study includes 80 extracted premolars of human from the patient visiting for orthodontic treatment of Coorg Institute of Dental Sciences, Karnataka, India. The brackets were debonded using four different methods. The enamel surface damage after the procedure was assessed with the Enamel Surface Index (ESI); similarly, the Adhesive Remnant Index (ARI) score was used to determine the adhesive residual deposit. Scanning electron microscopy (SEM) was used to visualize better microporosities and micromechanical retention of adhesive remnants on the enamel surface. The normality of the data was tested using the Kolmogorov-Smirnov test. Depending upon the normality test result, the one-way ANOVA test or Kruskal-Wallis test was used to test the mean ESI and mean ARI differences among different debonding methods along with the appropriate post hoc tests. The necessary ethical clearance was obtained from the Ethics Committee of the institute., Results: The ultrasonic scaler (US) technique led to more significant enamel surface damage, with 13 (65%) samples in the ESI scores III and IV against the satisfactory surface in 2 (10%) samples with the ligature cutter (LC) technique (ESI-I) reflecting LC as a better technique. The ESI scores (III and IV) for debonding plier (DP) and thermal method (TM) reflected a higher value in 12 (60%) and 10 (50%) samples and caused more damage to the enamel surface as compared to the LC technique. The ARI score was highest (ARI-1 = 40%) with the LC technique, followed by the US (ARI-1 = 20%), TM (ARI-1 = 15%), and DP (ARI-1 = 5%) methods. We have observed a significant association ( p value <0.05) of the ARI score among four different debonding ways in terms of each tooth's residual adhesive after the bracket removal., Conclusion: The result establishes the LC technique as a more acceptable one as it causes minimal harm to the debonded surface. The adhesive left on the debonded area is also minimum as compared to the other three methods tested. Therefore, it can be suggested as an ideal method., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Neelutpal Bora et al.)

This study aimed to evaluate (1) the overall reasons for first revision in CoC THAs; (2) whether the reasons for revision differ between third-generation and fourth-generation CoC THAs; and (3) the specific factors associated with bearing-related problems as the reason for revision. We retrospectively reviewed 2045 patients (2194 hips) who underwent first revision THA between 2004 and 2013, among which 146 hips with CoC bearings underwent revision. There were 92 hips with third-generation ceramic bearings and 54 hips with fourth-generation ceramic bearings. The major reasons for CoC THA revisions were ceramic fracture and loosening of the cup or stem. When ceramic fracture, squeaking, incorrect ceramic insertion, and unexplained pain were defined as directly related or potentially related to ceramic use, 28.8% (42/146) of CoC revisions were associated with bearing-related problems. Among the third-generation ceramic bearings, revision was performed in 41.3% (38/92) of cases owing to bearing-related problems whereas revisions were performed for only 7.4% (4/54) of cases with fourth-generation ceramic bearings owing to bearing-related problems (p < 0.001). Younger age, lower American Society of Anesthesiologists (ASA) grade, and preoperative diagnosis of osteonecrosis were factors related to CoC THA revisions due to bearing-related problems.

Background: Identifying the functional materials inside vaping devices can help inform efforts to understand risk. While nicotine E-cigarette components and metals have been characterized in several previous studies, the internal component compositions of tetrahydrocannabinol (THC) cartridge designs are not as well known. The 2019-20 e-cigarette or vaping product use associated lung injury (EVALI) outbreak has been associated with THC devices containing vitamin E acetate (VEA), possibly mediated by chemical reactions with internal cartridge components and high filament temperatures., Methods: We investigate the composition and internal components of 2019 EVALI patient-associated THC vaping devices compared to other THC and nicotine devices from 2016-19, specifically the metal, ceramic, and polymer components likely to be exposed to heat. To do this, we have disassembled forty-eight components from eight used and unused vaping devices under a microscope and analyzed them using X-ray fluorescence, scanning electron microscopy, and Fourier-transform infrared micro-spectroscopy., Conclusions: The two THC cartridges used by EVALI patients exhibited evidence of localized high temperatures, including charring of the ceramic heating elements and damaged wire surfaces. The newer THC cartridges possessed more ceramic and polymer insulation than older THC or nicotine devices. The combination of ceramics, metals, and high temperatures in newer THC cartridges is consistent with conditions hypothesized to produce VEA reactions during vaping. Nickel and chromium components were detected in all devices, and others contained copper, lead, tin, gold, silicon-rich rubbers, or fluorinated microplastics. These components have the potential to thermally degrade and volatilize if heated sufficiently. These findings do not imply that harmful exposures would occur under all usage conditions, and are most relevant to harm reduction efforts based on avoiding higher internal temperatures. This study was limited to a small sample of cartridges obtained from investigations. Future work should test more device types and internal temperatures under controlled usage conditions., Competing Interests: The authors have declared that no competing interests exist.

Background: Highly cross-linked polyethylene (HXLPE) enhances the anti-wear characteristics of the conventional polyethylene (PE). Early failure for wear after ceramic-on-highly cross-linked polyethylene (CoHXLPE) total hip arthroplasty (THA) is extremely rare., Case Presentation: We described the case of a 60-year-old man who underwent right CoHXLPE THA because of the developmental dysplasia hip (DDH) complained pain 32 months after this procedure. Plain radiographs showed that eccentric wear existed at the polyethylene insert. However, the patient refused surgery at that time and did not stop weight-bearing. The right hip pain continued for 7 months. Plain radiographs of the pelvis showed that the HXLPE liner was penetrated and partial inner wall of acetabular shell was worn. Acetabular cup revision was performed, and the ceramic head and HXLPE were exchanged., Conclusions: Difficult reduction during primary THA, especially for DDH, can result in higher abductor tension, which may lead to early eccentric wear of the prosthesis. Whenever eccentric wear of HXLPE liner was found, weight-bearing must be stopped to avoid the accelerated wear and adverse reactions to metal debris (ARMD).

(1) Background: Aluminum oxide (Al 2 O 3 ) ceramic is one of the materials used for artificial joints, and it has been known that their fine particles (FPs) are provided by the wear of the ceramic. Al 2 O 3 FPs have been shown to induce macrophage activation in vitro; however, the inflammatory effect in vivo has not been studied. (2) Methods: We examined the in vivo effect of Al 2 O 3 FPs on the innate and adaptive immune cells in the mice. (3) Results: Al 2 O 3 FPs promoted the activation of spleen macrophages; however, conventional dendritic cells (cDCs), plasmacytoid DCs (pDCs), and natural killer (NK) cells were not activated. In addition, increases in the CD4 and CD8 T cells was induced in the spleens of the mice treated with Al 2 O 3 FPs, which differentiated into interferon-gamma (IFN-γ)-producing helper T1 (Th1) and cytotoxic T1 (Tc1) cells. Finally, the injection of Al 2 O 3 FPs exacerbated dextran sulfate sodium (DSS)-induced inflammation in the colon, mediated by activated and increased number of CD4 and CD8 T cells. (4) Conclusions: These data demonstrate that FPs of Al 2 O 3 ceramic may contribute to the exacerbation of inflammatory diseases in the patients.

This study investigates a comprehensive model of bone regeneration capacity of dypiridamole-loaded 3D-printed bioceramic (DIPY-3DPBC) scaffolds composed of 100% beta-tricalcium phosphate (β -TCP) in an immature rabbit model through the time of facial maturity. The efficacy of this construct was compared to autologous bone graft, the clinical standard of care in pediatric craniofacial reconstruction, with attention paid to volume of regenerated bone by 3D reconstruction, histologic and mechanical properties of regenerated bone, and long-term safety regarding potential craniofacial growth restriction. Additionally, long-term degradation of scaffold constructs was evaluated. At 24 weeks in vivo, DIPY-3DPBC scaffolds demonstrated volumetrically significant osteogenic regeneration of calvarial and alveolar defects comparable to autogenous bone graft with favorable biodegradation of the bioactive ceramic component in vivo. Characterization of regenerated bone reveals osteogenesis of organized, vascularized bone with histologic and mechanical characteristics comparable to native bone. Radiographic and histologic analyses were consistent with patent craniofacial sutures. Lastly, through application of 3D morphometric facial surface analysis, our results support that DIPY-3DPBC scaffolds do not cause premature closure of sutures and preserve normal craniofacial growth. Based on this novel evaluation model, this DIPY-3DPBC scaffold strategy is a promising candidate as a safe, efficacious pediatric bone tissue engineering strategy.

Objective: Wear-induced aseptic loosening has been accepted as one of the main reasons for failure of total hip arthroplasty. Ceramic wear debris is generated following prosthesis implantation and plays an important part in the upregulation of inflammatory factors in total hip arthroplasty. The present study investigates the influence of ceramic debris on osteoblasts and inflammatory factors., Methods: Ceramic debris was prepared by mechanical grinding of an aluminum femoral head and added to cultures of MC3T3-E subclone 14 cells at different concentrations (i.e. 0, 5, 10, and 15 μg/mL). Cell proliferation was evaluated using a Cell Counting Kit (CCK-8), and cell differentiation was assessed by mRNA expression of alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). In addition, cell bio-mineralization was evaluated through alizarin red S staining, and release of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6) was measured through enzyme-linked immunosorbent assays (ELISA). Furthermore, mRNA expression of Smad1, Smad4, and Smad5 and protein expression of phosphorylated Smad1, Smad4, and Smad5 were measured by reverse transcriptase polymerase chain reaction (RT-PCR) and western blotting., Results: The ceramic debris had irregular shapes and sizes, and analysis of the size distribution using a particle size analyzer indicated that approximately 90% of the ceramic debris was smaller than 3.2 μm (2.0 ± 0.4 μm), which is considered clinically relevant. The results for mRNA expression of ALP, OCN, and OPN and alizarin red S staining indicated that cell differentiation and bio-mineralization were significantly inhibited by the presence of ceramic debris at all tested concentrations (P < 0.05, and the values decreased gradually with the increase of ceramic debris concentration), but the results of the CCK-8 assay showed that cell proliferation was not significantly affected (P > 0.05; there was no significant difference between the groups at 1, 3, and 5 days). In addition, the results of ELISA, RT-PCR, and western blotting demonstrated that ceramic debris significantly promoted the release of inflammatory factors, including TNF-α, IL-β, and IL-6 (P < 0.05, and the values increased gradually with the increase of ceramic debris concentration), and also greatly reduced the mRNA expression of Smad1, Smad4, and Smad5 (the values decreased gradually with the increase of ceramic debris concentration) as well as protein expression of phosphorylated Smad1, Smad4, and Smad5., Conclusion: Ceramic debris may affect differentiation and bio-mineralization of MC3T3-E subclone 14 cells through the bone morphogenetic protein/Smad signaling pathway., (© 2019 The Authors. Orthopaedic Surgery published by Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.)

Background: Total hip arthroplasty (THA) is used increasingly in younger patients. There is little knowledge about the effect of THA characteristics on risk of revision, especially in young patients. Therefore, we studied the influence of both patient-related and surgical factors on the risk of revision using data from the Dutch Arthroplasty Registry (LROI)., Methods: All patients younger than 55 years with a primary THA implanted in the Netherlands between 2007 and 2017 were selected (n = 19,682). The covariates age, sex, primary diagnosis, ASA-classification, surgical approach, fixation method, bearing type, head size and year of surgery were entered into Cox proportional hazards models to calculate hazard ratios for the risk of revision., Results: The overall 5-year survival of primary THA was 95.3% (95% CI, 94.9-95.6). Use of the anterior approach resulted in a lower risk of revision than the use of the posterolateral approach (HR: 0.66, 95% CI: 0.47-0.92). THAs with a head diameter ≥ 38 mm had a higher risk of revision (HR: 1.90, 95% CI: 1.33-2.72) than THAs with 32 mm heads. Use of MoM bearings resulted in an increased risk when compared to C-PE (HR: 1.76, 95% CI: 1.27-2.43)., Conclusion: The risk of revision in patients younger than 55 years depends on surgical approach, head size and bearing type. The anterior approach resulted in a decreased risk of revision, whereas use of ≥38 mm heads and MoM bearings resulted in an increased risk of revision for any reason.

Background: Head breakage is a serious complication following total hip arthroplasty when using Ceramic on Ceramic bearings surfaces. There is still in controversy about the selection of bearing surfaces when conducting revision surgery., Case Presentation: We describe the case of a fifty-year-old man who had undergone right total hip arthroplasty (THA) with ceramic-on-ceramic prostheses in 2011. After a fall 6 years after the primary procedures, radiographs suggested a ceramic head breakage for revision THA with exchange of metal-on-polyethylene bearing. However, 8 months later, severe metallosis and multiple pseudotumor was confirmed in pelvis and surrounding hip after re-revision THA with ceramic-on-polyethylene prostheses. Analysis of the serum metal ion indicated massive wear of the metal head and erosion of the stem neck and taper., Conclusions: This case vividly demonstrates metal bearings should be avoided and revision with complete synovectomy and thorough debridement should be performed whenever possible for a fractured ceramic bearing.

Background: Using data from the Korean Hip Registry, we aimed to investigate mid-term clinical and radiographic outcomes, including the prevalence of periprosthetic joint infection (PJI), osteolysis, and component loosening or dislocation, and to analyze the incidence of bearing-related complications following modern ceramic-on-ceramic (COC) total hip arthroplasty (THA) using a single cementless hip system., Methods: Four hundred eighty-two patients (602 hips) who underwent Forte or Delta COC THAs with a single hip system and had a minimum 5-year follow-up were identified. The sample included 243 (50.4%) women and 239 (49.6%) men with a mean age of 50.6 years (range: 18-83 years). The Forte group comprised 310 hips, and the Delta group comprised 292 hips. The mean follow-up was 6.1 years (range: 5-10.2 years)., Results: Cup orientation did not differ between groups. No hip had a PJI or osteolysis in either group. All acetabular components and all but two femoral components (in the Delta group) were well fixed. Dislocations occurred in six (1.9%) hips in the Forte group and one (0.3%) hip in the Delta group (p = 0.124). A total of nine (1.5%) revisions were performed. The 5-year survival rates for all-cause revisions were 98.4 and 98.6%, respectively. One (0.3%) ceramic head fracture occurred in the Forte group. Sixteen (5%) hips exhibited clicking and 6 (2%) hips had squeaking in the Forte group; 16 (6%) hips exhibited clicking and 5 (2%) hips had squeaking in the Delta group. Multiple regression analysis revealed that noise generation was unassociated with any factor., Conclusions: From the Korean Hip Registry data, THA with modern ceramic bearings showed encouraging results, with lower risks of PJI, osteolysis, and component loosening. In particular, Delta COC THA resulted in no PJI or ceramic fracture and had a reduced dislocation risk. However, associated noise remains a concern.

Introduction: Silicosis is still one of the the most common occupational disease in the world. The ceramic industry is one of the main sectors where silicosis patients are increasingly reported. The aim of this study was to evaluate the differences in demographic characteristics, radiological findings and pulmonary function test results of the ceramic workers with silicosis and those did not develop the disease., Materials and Methods: A total of 626 workers, 459 with silicosis and 167 without silicosis, working in the ceramics industry those admitted to Ankara Occupational and Environmental Diseases Hospital between 2009 and 2018 were included in the study. The cases were evaluated retrospectively., Result: The median age and duration of work of the workers with silicosis were significantly higher (p< 0.001) compared to workers without silicosis. The risk of silicosis was found to be 22.5 times higher in 50 years or older age. Working 11-20 years and more than 20 years increased the risk of silicosis by 3.1 fold and 3.9 fold respectively. Smoking more than 10 package-years was found to increase the risk of silicosis 2 fold. The workers who had worked in clay processing, sanding, glazing or smelting were found to have 5.2-fold, 3.8-fold 2.5 and 2.4 fold higher silicosis risk, respectively., Conclusions: In this study, it has been shown that older age, longer duration of work, smoking, working in clay processing, sanding, glazing or smelting sections increase the risk of silicosis in ceramic workers.

The present study aimed to evaluate the clinical outcomes and bearing-specific complications in a single center of 135 delta ceramic-on-ceramic (COC) total hip arthroplasties (THAs) and explore the occurrence rate of squeaking in 4th generation COC THAs and collate the risk factors for squeaking.We retrospectively analyzed consecutive cohorts of 127 patients (135 hips) who had primary THA with delta COC bearings in our hospital between April 2010 and April 2012. Preoperative Harris hip score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and University of California Los Angeles (UCLA) activity score were evaluated preoperatively and postoperatively. We also evaluated ceramic fracture, squeak, mid-term results, and survival.In our study, the final patient final follow-up date was July 31, 2016. The mean preoperative HHS improved from 39.5 to 93.1 points. Mean preoperative UCLA score was 3.2 points, improving to 8.2 points. The mean preoperative total WOMAC score was 55.5 points and the mean total WOMAC score was 13.3 points at the final follow-up. The Kaplan-Meier survival plot of revision for any reason as the end point was 98.5% and survival with ceramic fracture as the end point was 99.2% at a mean of 70 months' follow-up. One post-operative ceramic liner rim fracture occurred at 50 months after surgery. Thirteen of the 135 hips produced a squeaking sound. There were no significant differences in gender (P = .56), age (P = .20), body mass index (BMI) (P = .11), diagnosis (P = .46), cup inclination (P = .36), or cup anteversion (P = 1.0) between the squeaking and non-squeaking groups. However, the incidence of squeaking in the 36 mm COC femoral head bearings was higher than in the 28 mm size (13.6% vs 2.1%, P = .033).The 4th generation COC bearing performed well and provides an encouraging rate of survival with no osteolysis or loosening. However, we found that a squeaking sound associated with use of the delta ceramic occurred at a rate of 9.6%, with the larger-diameter heads having significantly higher incidence.

Background: Traditional ceramics are a cultural heritage in Mexico, used by the general population in everyday life. These ceramics are glazed with lead oxide and are usually produced in households that share living and working spaces. Glazing is usually performed by women, and children are not restrained from the work space and frequently help, resulting in high levels of lead exposure for all. Interventions that promote a change in technology (such as lead-free glazes or efficient kilns) are often unrealistic for potters with fewer economic resources who depend on their production as their main income. Interventions focusing on exposure prevention (rather than a technology change) at the household level are scarce., Methods: Working hand-in-hand with a group of nine women, lay community workers, promotoras, from Santa Fe de Laguna, Michoacán, we developed a program focusing on the self-recognition of health risks. The program was composed of health education (including a lead in blood and bone measurement for women), health/work risk recognition and communication to the community, and work/living area reorganization and remediation in three stages: work with 1) promotoras, 2) their extended families, and 3) their community, including talks in elementary schools., Results: The promotoras developed and distributed risk communication graphic materials and delivered a lead-awareness talk in the Purhepecha language, in the local primary health-care clinic and three elementary schools. Lead in bone levels had a mean ± SD (min, max) of rotula: 84.8 μg/g ± 68.9 (23.89, 214.2), tibia 93.2 μg/g 81.2 (14.23, 261.21). We implemented safer and cleaner ceramic production in the promotoras workshops.Public Health Relevance: Environmental and occupational exposures can be reduced through programs that are tailored by and for a specific community. When there is no evident alternative technology for safer production, such programs can empower groups and lead to reduced exposure for their children, family and community., Competing Interests: The authors have no competing interests to declare., (© 2018 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/.)

Background: Work-related asthma (WRA) constitutes a significant proportion of all asthma cases and continues to be reported from different industries. The aim of the study was to identify the occupations that can be related to WRA and diagnostic steps used in suspected WRA patients., Methods: We retrospectively reviewed the clinical records of WRA suspected patients who were referred to Ankara Occupational and Environmental Diseases Hospital, Turkey from January 2015 to January 2017. Detailed occupational history, the diagnostic steps such as pulmonary function testing (PFT), peak expiratory flow (PEF) monitoring and nonspecific bronchial provocation tests (NSBPT) were recorded., Results: Among 160 patients, 148 were male and 12 were female. Only 2 of them were diagnosed as work-exacerbated asthma (WEA). Diagnosis of asthma was based on using reversible airflow limitation 28.8% (n = 46) or NSBPT 31.9% (n = 51). Toxicological analysis showed that 28 patients had heavy metal poisoning, 9 patients had solvent poisoning, 4 patients had both. According to occupations, 32 of them were ceramic workers (20.0%) and 27 of them were metal workers (16.9%). Plastic workers (4 ± 2.8 years), cleaners (6.2 ± 5.7 years), metal workers (7.4 ± 5.4 years), painters (10 ± 5.2 years), ceramic workers (10.8 ± 5.9 years) had the shortest exposure durations for development of occupational asthma (OA). An analysis of variance showed that the effect of heavy metal and solvent poisoning on mean time for onset of OA was not significant., Conclusions: The results demonstrate that besides the sectors known to cause WRA, ceramic and metal industries can be related to important exposures related to WRA. Medical surveillance of employees in this sector is important in early detection., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Luting agents used to fix artificial prostheses, such as fixed partial denture (FPD) to tooth are basically viscous in nature and show chemical reaction for fixation. Postcementation hypersensitivity is a frequent complaint of patients. The present study was conducted to compare postcementation hypersensitivity with zinc phosphate and self-adhesive resin in complete coverage crown., Materials and Methods: This study included 30 patients in which 60 porcelein fused to metal crowns was placed. Two metal crowns were placed in each patient in nonantagonis-tic contralateral quadrants. First crown was cemented with zinc phosphate cement, while the other was cemented with self-adhesive resin. Hypersensitivity was evaluated by visual analog scale (VAS) score and by clinical test. For clinical evaluation of sensitivity, hot and cold water was applied to the cervical margin of restoration for 5 seconds and response was recorded., Results: This study consisted of 30 patients in which 60 crowns were given. There was no statistical difference in VAS score of mastication in zinc phosphate cement recorded at baseline, 1 week, 4 weeks, 6 months, 1 year, and 2 years (p > 0.05). Cold response also did not show a significant difference at six time points. Warm response showed slight decrease in subsequent time points but was nonsignificant (p > 0.05). Similarly, with self-adhesive resin cement, VAS score during mastication, hot and cold response was statistically nonsignificant (p > 0.05)., Conclusion: Postcementation hypersensitivity is a frequent complaint that patient may experience. However, we found no statistically significant difference in both cements tested., Clinical Significance: Postcementation hypersensitivity is an unpleasant sensation experienced by patients. This may affect the success of any prosthesis. Thus, selection of luting agent for cementation plays an important role to eliminate this symptom.

Background . Increased metal ion levels following total hip arthroplasty (THA) with metal-on-metal bearings are a highly debated topic. Local soft tissue reactions with chronic pain and systemic side effects such as neuropathy are described. The aim of the current study was to determine the serum metal ion concentrations of Cobalt (Co) and Chrome (Cr) after THA with a ceramic-on-metal (CoM) bearing. Patients and Methods . Between 2008 and 2010, 20 patients underwent THA using a CoM bearing. Clinical function was evaluated by standardized scores systems (Harris Hip Score and WOMAC Score) and radiological examination included X-rays. Patient's blood samples were obtained for metal ion analysis and correlation analysis was done between these results and implant position. Results . Overall, 13 patients with 14 CoM devices were available for the current series. The mean age at time of surgery was 61 years (range, 41 to 85). The postoperative follow-up ranged from 49 to 68 months (mean, 58). Metal ion determination showed mean concentrations of 3,1  µ g/L (range, 0,3-15,2  µ g/L) for Co and 1,6  µ g/L (range, 0,1-5,5  µ g/L) for Cr, respectively. A correlation between cup anteversion and Co and Cr concentrations was shown. Conclusion . The current series showed increments for Co and Cr following CoM THA. However, these levels are lower compared to metal ion concentrations in patients with metal-on-metal bearings and the international accepted threshold for revision of MoM devices. We recommend routine follow-up including at least one obligatory evaluation of serum metal ion concentrations and an MRI once to exclude local soft tissue reactions.

Background: Aseptic loosening is a significant impediment to joint implant longevity. Prosthetic wear particles are postulated to play a central role in the onset and progression of periprosthetic osteolysis, leading to aseptic loosening of the prosthesis., Methods: We investigated the inhibitory effects of a lentivirus-mediated short hairpin RNA that targets the TNF-alpha gene on the particle-induced inflammatory and osteolytic changes via macrophages both in vitro and in vivo. An siRNA sequence targeting the mouse TNF-alpha gene from four candidates, transcribed in vitro, was screened and identified. A lentivirus vector expressing short hairpin RNA (shRNA) was then constructed in order to facilitate efficient expression of TNF-alpha-siRNA. Lentivirus-mediated shRNA was transduced into cells of the mouse macrophage line RAW 264.7. Ceramic and titanium particles were introduced 24 h after lentivirus transduction to stimulate cells. TNF-alpha expression, represented by both mRNA and protein levels, was quantified with real-time PCR and ELISA at all time intervals. Lentivirus-mediated shRNA suspension was locally administered into the murine calvarial model, followed by local injection of particles. A multi-slice spiral CT scan was used to evaluate the osteolysis of the calvaria by detecting the width of the cranial sutures., Results: Macrophages developed pseudopods when co-cultured with particles. Lentivirus-mediated shRNA was shown to effectively inhibit the expression of TNF-alpha at both the mRNA and protein levels in RAW 264.7. The multi-slice spiral CT scan showed that the lentivirus-mediated shRNA significantly suppressed osteolysis of mouse calvaria., Conclusions: Our investigation highlighted the results that lentivirus-mediated shRNA targeting the TNF-alpha gene successfully inhibited particle-induced inflammatory and osteolytic changes both in vitro and in vivo. Therefore, lentivirus-mediated gene therapy may provide a novel therapeutic approach to aseptic joint loosening.

Background: Preliminary studies have raised the question of whether certain prosthetic biomaterials used in total hip arthroplasty (THA) bearings are associated with increased risk of periprosthetic joint infection (PJI). For example, some observational data suggest the risk of PJI is higher with metal-on-metal bearings. However, it is not known whether other bearings-including ceramic bearings or metal-on-polyethylene bearings-may be associated with a higher or lower risk of PJI., Questions/purposes: The objective of this study was to use a national arthroplasty registry to assess whether the choice of bearings-metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), or metal-on-metal (MoM)-is associated with differences in the risk of revision for deep infection, either (1) within 6 months or (2) over the entire period of observation, which spanned 15 years., Methods: Data from primary THAs were extracted from the New Zealand Joint Registry over a 15-year period. A total of 97,889 hips were available for analysis. Inclusion criterion was degenerative joint disease; exclusion criteria were previous surgery, trauma, and any other diagnosis (12,566 hips). We also excluded a small group of ceramic-on-metal THAs (429) with short followup. The median observation period of the selected group of hips (84,894) was 9 years (range, 1-15 years). The mean age of patients was 68 years (SD ± 11 years), and 52% were women. There were 54,409 (64%) MoP, 16,503 (19%) CoP, 9051 (11%) CoC, and 4931 (6%) MoM hip arthroplasties. Four hundred one hips were revised for deep infection. A multivariate assessment was carried out including the following risks factors available for analysis: age, sex, operating room type, use of body exhaust suits, THA fixation mode, and surgeon volume. Because of late introduction of data collection in the Registry, we were unable to include body mass index (BMI, recording started 2010) and medical comorbidities according to the American Society of Anesthesiologists class (ASA, recording started 2005) in the multivariate analysis., Results: The rate of early PJI (< 6 months) did not differ by bearing surface. In contrast, we observed a difference over the total observation period. Within the first 6 months after the index surgery, CoC THAs were not associated with a lower risk of revision for PJI (p = 0.118) when compared with CoP (hazard ratio [HR], 1.31; 95% confidence interval [CI], 0.50-3.41), MoP (HR, 2.10; CI, 0.91-4.82), and MoM (HR, 2.04; CI, 0.69-6.09). When the whole observation period was considered, CoC hips were associated with a lower risk of revision for deep infection when compared with CoP (HR, 1.30; CI, 0.78-2.18; p = 0.01), MoP (HR, 1.75; CI, 1.07-2.86; p = 0.02), and MoM (HR, 2.12; CI, 1.23-3.65; p = 0.008)., Conclusions: Our finding associating CoC THA bearings with a lower risk of infection after THA must be considered very preliminary, and we caution readers against attributing all of the observed difference to the bearing surface. It is possible that some or all of the observed difference associated with bearing type may have been driven by other factors such as ASA and BMI, which could not be included in our multivariate analysis, and so future registry studies on this topic must assess those variables carefully., Level of Evidence: Level III, therapeutic study.

Unlabelled: Foreign body giant cells (FBGCs) and osteoclasts are multinucleated giant cells (MNGCs), both of which are formed by the fusion of macrophage-derived mononuclear cells. Osteoclasts are distinct from FBGCs due to their bone resorption ability; however, not only morphological, but also functional similarities may exist between these cells. The characterization and diversity of FBGCs that appear in an in vivo foreign body reaction currently remain incomplete. In the present study, we investigated an in vivo foreign body reaction using an extraskeletal implantation model of hydroxyapatite (HA) with different microstructures. The implantation of HA granules in rat subcutaneous tissue induced a foreign body reaction that was accompanied by various MNGCs. HA granules composed of rod-shaped particles predominantly induced cathepsin K (CTSK)-positive FBGCs, whereas HA granules composed of globular-shaped particles predominantly induced CTSK-negative FBGCs. Plasma, which was used as the binder of ceramic granules, stimulated the induction of CTSK-positive FBGCs more strongly than purified fibrin. Furthermore, the implantation of HA composed of rod-shaped particles with plasma induced tartrate-resistant acid phosphatase (TRAP)-positive MNGCs in contrast to HA composed of globular-shaped particles with purified fibrin, which predominantly induced CTSK-negative and TRAP-negative typical FBGCs. These results suggest that CTSK-positive, TRAP-positive, and CTSK- and TRAP-negative MNGCs are induced in this subcutaneous implantation model in a manner that is dependent on the microstructure of HA and presence or absence of plasma., Statement of Significance: We attempted to elucidate the mechanisms responsible for the foreign body reaction induced by the implantation of hydroxyapatite granules with different microstructures in rat subcutaneous tissue with or without plasma components as the binder of ceramic granules. By analyzing the expression of two reliable osteoclast markers, we detected tartrate-resistant acid phosphatase-positive multinucleated giant cells, cathepsin K-positive multinucleated giant cells, and tartrate-resistant acid phosphatase- and cathepsin K-negative multinucleated giant cells. The induction of tartrate-resistant acid phosphatase-positive multinucleated giant cells was plasma component-dependent while the induction of cathepsin K-positive multinucleated giant cells was influenced by the microstructure of hydroxyapatite. This is the first study to show the conditions dividing the three kinds of multinucleated giant cells in the foreign body reaction., (Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Background: Modern ceramic (CoC) bearings for hip arthroplasty (THA) have been used in younger patients who expect improved survivorship. However, audible squeaking produced by the implant is an annoying complication. Previous numerical simulations were not able to accurately reproduce in vitro and in vivo observations. Therefore, we developed a finite element model to: (1) reproduce in vitro squeaking and validate the model by comparing it with in vivo recordings, (2) determine why there are differences between in vivo and in vitro squeaking frequencies, (3) identify the stem's role in this squeaking, (4) predict which designs and materials are more likely to produce squeaking., Hypothesis: A CoC THA numerical model can be developed that reproduces the squeaking frequencies observed in vivo., Material and Methods: Numerical methods (finite element analysis [ANSYS]) and experimental methods (using a non-lubricated simulated hip with a cementless 32mm CoC THA) were developed to reproduce squeaking. Numerical analysis was performed to identify the frequencies that cause vibrations perceived as an acoustic emission. The finite element analysis (FEA) model was enhanced by adjusting periprosthetic bone and soft tissue elements in order to reproduce the squeaking frequencies recorded in vivo. A numerical method (complex eigenvalue analysis) was used to find the acoustic frequencies of the squeaking noise. The frequencies obtained from the model and the hip simulator were compared to those recorded in vivo., Results: The numerical results were validated by experiments with the laboratory hip simulator. The frequencies obtained (mean 2790Hz with FEA, 2755Hz with simulator, decreasing to 1759Hz when bone and soft tissue were included in the FEA) were consistent with those of squeaking hips recorded in vivo (1521Hz). The cup and ceramic insert were the source of the vibration, but had little influence on the diffusion of the noise required to make the squeaking audible to the human ear. The FEA showed that diffusion of squeaking was due to an unstable vibration of the stem during frictional contact. The FEA predicted a higher rate of squeaking (at a lower coefficient of friction) when TZMF™ alloy is used instead of Ti6Al4V and when an anatomic press-fit stem is used instead of straight self-locking designs., Discussion: The current FEA model is reliable; it can be used to assess various stem designs and alloys to predict the different rates of squeaking that certain stems will likely produce., Level of Evidence: Level IV in vitro study., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Background: Our purpose was to record the incidence of heterotopic ossification (HO) following hip replacement by different variables to identify patient groups that are likely to develop HO in the absence of a prophylactic protocol., Methods: Radiographically, we studied 651 patients having undergone hip joint replacement, evaluating three kinds of implants: ceramic-ceramic-coupled total hip replacement (THR), TriboFit® with polycarbonate urethane-ceramic coupling and endoprosthesis. Each patient was analysed for HO development by age, gender, diagnosis, presence of previous ossifications, surgical approach and kind of implant. Within the population that developed HO, data were assessed for correlation with severity of ossification graded according to Brooker classification., Results: The overall incidence of HOs was 59.91 %. The factors increasing their incidence in the univariate analysis were as follows: lower age of the patients with HO (mean 77.6 years, p = 0.0018) than those subjects who did not develop HO (mean 80.2 years); male gender (64.4 %, p = 0.1011); diagnosis of coxarthrosis (72.7 %, p = 0.0001) compared to femur neck fracture (55.9 %, p = 0.0001); presence of previous HO (76.2 %, p = 0.0260); lateral approach (65.5 %) as opposed to anterior-lateral approach (55.6 %, p = 0.0163); and ceramic-ceramic THR (68.1 %) and TriboFit® (67.0 %) compared to endoprosthesis (51.3 %, p = 0.0001). During multivariate analysis, the presence of HO after previous hip surgery (p = 0.0324) and the kind of implant (p = 0.0004) showed to be independent risk factors for the development of HO. Analysing the population that developed HO, we found that the severity of ossification by Brooker classification was influenced by gender (p = 0.0478) and kind of implant (p = 0.0093)., Conclusions: In agreement with the literature, our radiographic study confirms the following risk factors of HO development in absence of any prophylactic treatment: male gender, diagnosis of coxarthrosis compared to femur neck fracture, previous HO, surgical approach and kind of implant. In particular, Hardinge-Bauer and Watson-Jones surgical approaches, characterized by a wide exposure of the coxofemoral joint, and ceramic-ceramic THR and TriboFit® implants significantly increase the development of HO.

Objective: To find out whether the use of lead-glazed ceramic (LGC) is associated with blood lead levels in indigenous schoolchildren from Oaxaca, México., Materials and Methods: We evaluated LGC use at home as a primary source of lead exposure in 387 indigenous schoolchildren in Oaxaca in May 2001., Results: We found an adjusted difference of 3.9μg/dl (p<0.01) in blood lead levels (BLL) among children reporting to use (82%) LGC at home vs those who didn't. BL levels greater or equal than 10 and 20 μg/dl were observed in 60 and 27% of children, respectively., Conclusions: Lead poisoning from LGC use could remain a concern for public health in Mexico, where there is a need to provide care and further study to verify its effect on BLL.

Metal transfer has been observed on retrieved THA femoral heads for both CoCr and ceramic bearing materials. In vitro wear testing has shown increased wear to polyethylene acetabular liners with the presence of metal transfer. This study sought to investigate the extent of metal transfer on the bearing surface of CoCr and ceramic femoral heads and identify prevalent morphologies. Three bearing couple cohorts: M-PE (n = 50), C-PE (n = 35), and C-C (n = 15), were derived from two previously matched collections (n = 50/group) of CoCr and ceramic femoral heads. From the three cohorts, 75% of the femoral heads showed visual evidence of metal transfer. These femoral heads were analyzed using direct measurement, digital photogrammetry, and white light interferometry. Surface area coverage and curved median surface area were similar among the three cohorts. The most prevalent metal transfer patterns observed were random stripes (n = 21/75), longitudinal stripes (n = 17/75), and random patches (n = 13/75). Metal transfer arc length was shorter in the M-PE cohort. Understanding the morphology of metal transfer may be useful for more realistic recreation of metal transfer in in vitro pin-on-disk and joint simulators studies.

The aim of this study was to investigate the hypothesis of an increased risk of pleural mesothelioma due to co-exposure to asbestos and refractory ceramic fibres (RCF) compared to asbestos exposure alone. Males were selected from a French case-control study conducted in 1987-1993 and from the French National Mesothelioma Surveillance Program in 1998-2006. Two population controls were frequency matched to each case by year of birth. Complete job histories were collected and occupational asbestos and RCF exposures were assessed using job exposure matrices. The dose-response relationships for asbestos exposure were estimated from an unconditional logistic regression model in subjects exposed to asbestos only (group 1) and subjects exposed to both asbestos and RCF (group 2). A total of 988 cases and 1125 controls ever-exposed to asbestos were included. A dose-response relationship was observed in both groups but it was stronger in group 2. In comparison with subjects exposed at the minimum value of the cumulative index of exposure, the odds ratio was 2.6 (95% CI 1.9-3.4) for subjects exposed to 75 fibres · mL(-1) · year(-1) in group 1 increasing to 12.4 (95% CI 4.6-33.7) in group 2. Our results suggest that the pleural carcinogenic effect of occupational asbestos exposure may be modified by additional exposure to RCF., (©ERS 2014.)

Background: Bioactive glass-ceramics have the ability to directly bind to bones and have been widely used as bone graft substitutes due to their high osteoconductivity and biocompatibility. CaO-SiO2-P2O5-B2O3 glass-ceramics are known to have good osteoconductivity and are used as bone graft extenders., Methods: This study aimed to evaluate the effects of the resorbing properties of glass-ceramics in bone fusion after producing and analyzing three types of CaO-SiO2-P2O5-B2O3 glass-ceramics with high osteoconductivity that had enhanced resorption by having an increased B2O3 content. The three types of CaO-SiO2-P2O5-B2O3 glass-ceramics with B2O3 contents of 8.0, 9.0, and 9.5 weight % were designated and grouped as P20B80, P10B90, and P5B95, respectively. Glass-ceramic types were tested for fusion rates and bone formation by employing the lumbar 5-6 intertransverse process fusion model in 51 New Zealand male rabbits. Bioactivity was assessed by soaking in simulated body fluid (SBF)., Results: In vitro study results showed sufficient hydroxycarbonate apatite layer formation occurred for P20B80 in1 day, for P10B90 in 3 days, and for P5B95 in 5 days after soaking in SBF. For the rabbit lumbar spine posterolateral fusion model, the autograft group recorded a 100% fusion rate with levels significantly higher than those of P20B80 (29.4%), P10B90 (0%), and P5B95 (14.3%), with high resorbing properties. Resorbing property differences among the three glass-ceramic groups were not significant. Histological results showed new bone formation confirming osteoconductivity in all three types of glass-ceramics. Radiomorphometric results also confirmed the resorbing properties of the three glass-ceramic types., Conclusions: The high resorbing properties and osteoconductivity of porous glass-ceramics can be advantageous as no glass-ceramics remain in the body. However, their relatively fast rate of resorption in the body negatively affects their role as an osteoconductive scaffold as glass-ceramics are resorbed before bony fusion.

Ceramic materials show excellent esthetic behavior, along with an absence of hypersensitivity, making them a possible alternative implant material in dental surgery. However, their surface properties enable only limited osseointegration compared to titanium implants. Within this study, a novel surface coating technique for enhanced osseointegration was investigated biologically and mechanically. Specimens of tetragonal zirconia polycrystal (TZP) and aluminum toughened zirconia (ATZ) were modified with glass solder matrices in two configurations which mainly consisted of SiO2, Al2O3, K2O, and Na2O. The influence on human osteoblastic and epithelial cell viability was examined by means of a WST-1 assay as well as live/dead staining. A C1CP-ELISA was carried out to verify procollagen type I production. Uncoated/sandblasted ceramic specimens and sandblasted titanium surfaces were investigated as a reference. Furthermore, mechanical investigations of bilaterally coated pellets were conducted with respect to surface roughness and adhesive strength of the different coatings. These tests could demonstrate a mechanically stable implant coating with glass solder matrices. The coated ceramic specimens show enhanced osteoblastic and partly epithelial viability and matrix production compared to the titanium control. Hence, the new glass solder matrix coating could improve bone cell growth as a prerequisite for enhanced osseointegration of ceramic implants.

Background: Dental caries is a common disease and affects many adults worldwide. Inlay or onlay restoration is widely used to treat the resulting tooth substance loss. Two esthetic materials can be used to manufacture an inlay/onlay restoration of the tooth: ceramic or composite. Here, we present the protocol of a multicenter randomized controlled trial (RCT) comparing the clinical efficacy of both materials for tooth restoration. Other objectives are analysis of overall quality, wear, restoration survival and prognosis., Methods: The CEramic and COmposite Inlays Assessment (CECOIA) trial is an open-label, parallel-group, multicenter RCT involving two hospitals and five private practices. In all, 400 patients will be included. Inclusion criteria are adults who need an inlay/onlay restoration for one tooth (that can be isolated with use of a dental dam and has at least one intact cusp), can tolerate restorative procedures and do not have severe bruxism, periodontal or carious disease or poor oral hygiene. The decayed tissue will be evicted, the cavity will be prepared for receiving an inlay/onlay and the patient will be randomized by use of a centralized web-based interface to receive: 1) a ceramic or 2) composite inlay or onlay. Treatment allocation will be balanced (1:1). The inlay/onlay will be adhesively luted. Follow-up will be for 2 years and may be extended; two independent examiners will perform the evaluations. The primary outcome measure will be the score obtained with use of the consensus instrument of the Fédération Dentaire Internationale (FDI) World Dental Federation. Secondary outcomes include this instrument's items, inlay/onlay wear, overall quality and survival of the inlay/onlay. Data will be analyzed by a statistician blinded to treatments and an adjusted ordinal logistic regression model will be used to compare the efficacy of both materials., Discussion: For clinicians, the CECOIA trial results may help with evidence-based recommendations concerning the choice of materials for inlay/onlay restoration. For patients, the results may lead to improvement in long-term restoration. For researchers, the results may provide ideas for further research concerning inlay/onlay materials and prognosis.This trial is funded by a grant from the French Ministry of Health., Trial Registration: ClinicalTrials.gov Identifier: NCT01724827.

Ceramic bearing surfaces are increasingly used for total hip replacement, notwithstanding that concern is still related to ceramic brittleness and its possible mechanical failure. The aim of this systematic review is to answer three questions: (1) Are there risk factors for ceramic component fracture following total hip replacement? (2) Is it possible to perform an early diagnosis of ceramic component failure before catastrophic fracture occurs? (3) Is it possible to draw guidelines for revision surgery after ceramic components failure? A PubMed and Google Scholar search was performed and reference citations from publications identified in the literature search were reviewed. The use of 28 mm short-neck femoral head carries an increased risk of fracture. Acetabular component malposition might increase the risk of ceramic liner fractures. Synovial fluid microanalysis and CT scan are promising in early diagnosis of ceramic head and liner failure. Early revision is suggested in case of component failure; no consensus exists about the better coupling for revision surgery. Ceramic brittleness remains a major concern. Due to the increased number of ceramic on ceramic implants, more revision surgeries and reports on ceramic components failure are expected in the future. An algorithm of diagnosis and treatment for ceramic hip failure is proposed.

An analysis was conducted on a cohort of Chinese pottery workers to estimate the exposure-response relationship between respirable crystalline silica dust exposure and the incidence of radiographically diagnosed silicosis, and to estimate the long-term risk of developing silicosis until the age of 65. The cohort comprised 3,250 employees with a median follow-up duration of around 37 years. Incident cases of silicosis were identified via silicosis registries (Chinese X-ray stage I, similar to International Labor Organisation classification scheme profusion category 1/1). Individual exposure to respirable crystalline silica dust was estimated based on over 100,000 historical dust measurements. The association between dust exposure, incidence and long-time risk of silicosis was quantified by Poisson regression analysis adjusted for age and smoking. The risk of silicosis depended not only on the cumulative respirable crystalline silica dust exposures, but also on the time-dependent respirable crystalline silica dust exposure pattern (long-term average concentration, highest annual concentration ever experienced and time since first exposure). A long-term "excess" risk of silicosis of approximately 1.5/1,000 was estimated among workers with all annual respirable crystalline silica dust concentration estimates less than 0.1 mg/m(3), using the German measurement strategy. This study indicates the importance of proper consideration of exposure information in risk quantification in epidemiological studies.

Penetrating cranial injury is a potentially life-threatening condition. The majority of war injuries are high-velocity penetrating cranial injuries; but in civilian cases, most penetrating cranial wounds are low-velocity type. We report an interesting case of transorbital penetrating cranial injury with a knife-sharpening stone made up of ceramic in a 28-year-old male. The pertinent literature is reviewed and management of such cases is discussed.

The nanostructured surface of a material can improve its interaction with cells and its acceptance as an implant. We compared two novel biomaterials with different nanostructures: Bioverit II with a coating of nanoporous silica and chitosan-hydroxyapatite composite materials. Pure Bioverit II served as a control. Platelets of these materials were implanted for 28, 85 and 300 days in the subcutaneous tissue in the neck of 38 rabbits. After excising the specimens they were fixed, embedded in epoxy resin and analyzed histologically. All coated Bioverit II implants showed a thin capsule of connective tissue. After 300 days, these capsules tended to be thicker than in pure Bioverit II. No signs of inflammation were observed and the materials appeared unaltered by visual inspection. In case of chitosan-hydroxyapatite composites, massive capsules consisting of dense connective tissue were found, and the material showed signs of biodegradation in form of fissures and cavities. In conclusion, the nanoporous coating showed no obvious positive effect with regard to capsule formation; the chitosan-hydroxyapatite implants provoked a stronger interaction between cells and material. However, most Bioverit II implants showed no alterations optically, whereas chitosan-hydroxyapatite was partly degraded in all cases.

As part of a wider epidemiological research programme, an occupational hygiene study was carried out during 1995-1996 to assess workers' current exposures to airborne materials in six European refractory ceramic fibre (RCF) plants. These plants had also participated in a cross-sectional occupational hygiene survey in 1987. The sampling strategy focussed principally on personal shift-average exposures of workers, by occupation, to respirable fibres. Monitoring was undertaken in two integrated phases: a 1-week cross-sectional survey followed by a prospective, and ongoing, programme by the RCF industry. Statistical (analysis of variance) analyses to identify patterns of variability by plant, occupational group (OG) and occupations within group were based on 464 individual shift samples, the greatest amount of data being available for production occupations. Concentrations of respirable fibres showed marked differences between plants and between OGs. Average respirable fibre concentrations among Primary and Secondary Production and Ancillary workers ranged from <0.1 f ml(-1) to up to 0.4 f ml(-1), depending on OG and plant. Individual shift-average measurements were almost invariably <1 f ml(-1). Within Secondary Conversion and Finishing, plant-specific averages ranged from 0.3 f ml(-1) to 1.25 f ml(-1). Respirable fibre concentrations were, in some plants, less than half those found in 1987. In other plants, mainly those where concentrations had been relatively low in 1987, the dust exposure had remained essentially unchanged or increased slightly. An ongoing programme of sampling is being carried out by the participating companies, generating additional information that could assist research in the long term and in improving control.

Few histological studies on bone substitutes in human cervical spine are available and the biological processes of bone substitutes are not well documented. The authors studied four failure cases of cervical interbody fusion: two cases with hydroxyapatite (HA), one case with beta-tricalcium phosphate ceramic (beta-TCP) and one case with xenograft (bovine bone). Clinical data showed that all the patients experienced neck pain with or without numbness of upper extremity due to fusion failure. Successful fusions were achieved after the salvage surgeries in which autograft were used. Radiographs showed that radiolucent lines were present in all cases. Two HA substitutes fractured without complications. One of them sank into the vertebral body. Some small beta-TCP fragments were found under the microscope. Histological study demonstrated only a few newly formed bones at the interface of the substitutes. The fragments of HA were encapsulated by fibrous tissue. The degradation process and bone regeneration were more active in beta-TCP than in HA. The intertrabecular spaces of bovine bone were filled with fibrous tissue. The results suggest that a porous calcium phosphate ceramic with special design might assure bone ingrowth and meet the mechanical requirements in cervical interbody fusion. The complications of these materials in the cervical spine should be highlighted.

The biocompatibility of dental materials is a topic of increasing importance for dentists. We investigated the effects of alloys for ceramic crowns and removable prostheses on the skin and lymphoid organs of rats. We used three groups of Sprague Dawley rats: group I as the control, with groups II and III implanted with different biomaterials into subcutaneous pockets. After sacrifice, the rat skin around the implant and the lymph nodes was studied. The tissues of implanted rats were morphologically different from the control animals as they showed a number of mast cells that increased 7 days after the implant with both alloys. These cells decreased 14 days after the implant with alloy for ceramic crowns whereas they were still high 28 days after the implant with alloy for removable prostheses. The findings suggest that both alloys induced different and time-dependent inflammatory reactions. Our findings have importance in the future rational design of biocompatible implantable and blood-contact biomaterials.

Lead intoxication risks were studied in a community of ceramic folk art workers in Oaxaca, a southern state of Mexico, where the manufacture of low-temperature lead ceramic ware is a family tradition and often the only source of income. Variables such as household characteristics, occupation, and lead exposure risk factors were explored. Study participants' mean blood lead concentration was 43.8 microg/dl (range=8.4-99.6 microg/dl), which is over the WHO guideline of 40 microg/dl for removing workers from exposure and is the concentration over which renal damage is accelerated. Best predictors for high blood lead concentrations by multivariable regression analysis were: occupation (P<0.0001), gender (P=0.0002), and the use of glazed stoneware (P<0.0001). This model explained 18% of blood lead variation among the study group. Exposure appears to be primarily associated with antiquated pottery manufacturing techniques and the high degree of contamination prevailing at the production sites, which in most cases are their living quarters. This consequently affects the lead levels of the entire community.

For more than 30 years aluminium oxide (Al(2)O(3)) ceramics have been used for implants in maxillofacial and orthopaedic surgery. Up to now, there are no reports and also no investigations on hypersensitivity reactions. In order to evaluate the aspects of immuno-allergological reactivity to aluminium oxide ceramics, skin testing and in vitro lymphocyte activation studies were performed. The patch test reactivity to a standard series of contact allergens and to an aluminium oxide (Al(2)O(3)) disk was examined in a consecutive series of 250 patients frequenting a University Dermatology Clinic. Furthermore, peripheral blood mononuclear cells (PBMC) of 15 nickel-allergic and 15 non-allergic individuals were cultured with medium alone, with the pan T-cell mitogen phytohemagglutinine (PHA) or with nickel sulfate (NiSO(4)). By additional presence/absence of Al(2)O(3) disk its influence on the cytokine secretion pattern and proliferative response was investigated. The results show that in contrast to a high frequency of delayed-type hypersensitivity to standard contact allergens, no allergic skin reactions to Al(2)O(3) ceramics occured. The IL-4 and IFN-gamma production in vitro remained almost unchanged by the presence of Al(2)O(3) disk as well as the proliferative response of PBMC of non-allergic individuals. Cellular reactivity of nickel allergic and non-allergic donors was partly enhanced upon contact to Al(2)O(3) disks.

Objective: Lead poisoning can, in some cases, be traced to a specific route or source of exposure on the basis of the individual's blood lead isotope ratio. To assess the major source of lead exposure among women residing in Mexico City, we compared blood, ceramic, and gasoline lead isotope ratios., Material and Methods: The study population, randomly selected from participants of a large trial, (1/1996-12/1996) comprised of 16 women whose lead levels exceeded 10 micrograms/dl and who reported using lead-glazed ceramics. Lead isotope ratios were performed on a Perkin Elmer 5000 Inductively Coupled Plasma Mass Spectrometer (ICP-MS) interfaced with a Perkin Elmer HGA-600MS Electrothermal Vaporization System (ETV)., Results: The isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb) of both the blood specimens and their corresponding ceramic specimens were highly correlated, with r = 0.9979, r2 = 0.9958, r = 0.9957, r2 = 0.9915 and r = 0.9945, r2 = 0.9890 values for the three isotope ratios, respectively, suggesting that the lead exposure most likely resulted from the use of these ceramic. Measurements of lead isotope ratios from leaded gasoline in use at the time of blood sampling, differed from those in blood and ceramics., Conclusions: Determining lead isotope ratios can be an efficient tool to identify a major source of lead exposure and to support the implementation of public health prevention and control measures. This paper is available too at: http://www.insp.mx/salud/index.html.

An accidental discovery led us to correlate a pathology of "unknown origin" with the presence of micro- and nano-particles of inorganic nature in the human tissues. Bioptic samples of livers and kidneys affected by cryptogenic granulomas were observed through a new type of electron scanning microscope called environmental scanning electron microscope and X-ray-microanalyzed with an energy dispersive system. All the randomly selected samples showed the presence of inorganic samples, sometimes varying in chemical composition, but consistent in size (larger in the liver, smaller in the kidney). This article illustrates the results obtained on randomly picked samples and proposes our new investigative method as an aid to achieve a medical diagnosis. Two more items are discussed: the possible, until now unexplained, origin of a pathology as deriving from the presence of exogenous particles, so a new word "nano-pathology" was developed and, as a consequence, the relativity of the concept of biocompatibility as depending on the size of the material considered and its local concentration. The implications of the discovery are briefly discussed.

Refractory ceramic fibers (RCF) are widely used to replace asbestos in applications requiring high heat resistance. Ferruginous bodies mimicking asbestos bodies (ABs) have been detected in the lungs of RCF production workers. This raises the question about their presence in other occupational groups and whether "typical ABs" still reflect past asbestos exposures in all settings. An AB counting by phase-contrast light microscopy and a screening test by analytical electron microscopy were systematically performed on all bronchoalveolar lavage fluids (BALF) submitted to our laboratory in 1992 through 1997 (n = 1,800). When RCF were detected in electron microscopy, the structures considered as "typical ABs" were marked under light microscopy and prepared for further chemical and structural analysis. Pseudo-ABs on RCF were detected in samples from nine subjects (0.5%). All of them had worked either as foundry workers, steel workers, or welders. In these subjects, alumino-silicate fibers compatible with RCF accounted for 42% of the core fibers analyzed, other nonasbestos fibers for 28%, and asbestos fibers for 30%. ABs thus remain a valid marker of asbestos retention but attention must be paid to a possible occurrence of pseudo-asbestos bodies on RCF and other nonasbestos fibers in end-users of refractory fibers.

Recently, the use of asbestos has been considerably limited in Poland, with the simultaneous increase in the manufacture, processing and application of man-made mineral fibres, which includes ceramic fibres. The aims of this study were (1) to assess the type and frequency of dermal changes caused by the irritant activity of ceramic fibres among workers at the plants that manufacture packing and insulation products; and (2) to compare the irritant activity of Polish-made L-2 and L-3 ceramic fibres with that of the Thermowool ceramic fibres made in England. Workers (n = 226) who were exposed to ceramic fibres underwent dermatological examination. Patch tests with the standard allergen set, together with samples of the fibres L-2, L-3, and Thermowool fibres, were applied to all the workers. It has been shown that the Polish-made L-2 and L-3 fibres differed from Thermowool fibres in that the L-2 and L-3 fibres contained zirconium and were coarser. The proportion of filaments with diameters above 3 microns was 11.1% in the L-3 fibre and 6.3% in the L-2 fibre samples. The Thermowool fibre did not contain filaments thicker than 3 microns. Evident dermal changes, resulting from strong irritant activity of the fibres, were detected in 109 (48.2%) of the workers examined. Irritant contact dermatitis acuta (maculae, sometimes papulae and small crusts on the upper extremities, trunk, and lower extremities), disappearing after 2-3 days, was found in 50 (22.1%) workers. Irritant contact dermatitis chronica (diffuse permanent erythema with numerous telangiectasiae on the lateral portions of the face and neck, on the trunk, behind the auricles) was detected in 40 (17.7%) workers. The remaining 19 (8.4%) workers had both types of dermal change. All examined workers complained of very strong itching. The results of the patch tests confirmed the irritant activity of the ceramic fibres. Erythema without oedema, persisting for up to 96 h, appeared at the places where the fibres had been applied to the skin in 44 (19.5%) workers. In addition, the irritant activity of the fibres has been shown to be correlated with their thickness. The Thermowool fibre was the weakest irritant, because it did not contain filaments above 3 microns in diameter; the L-2 fibre containing 6.3% filaments above 3 microns caused somewhat stronger skin irritation; while the L-3 fibre, which contained 11.1% filaments thicker than 3 microns, was the strongest irritant. A few cases of allergy to nickel, chromium and colophony (rosin) were also detected.

Objective: To investigate the relation between rheumatoid arthritis and occupational exposure to silica in pottery and related industries., Methods: Medical records of 8325 men and women born 1916-45 and employed in pottery, refractory material (aluminosilicate or silica), and sandstone industries were examined to identify cases of rheumatoid arthritis. Medical and employment histories were extracted for cases and matched referents. Indices of duration, cumulative exposure, and mean silica concentration were compiled. Conditional logistic regression was used to investigate the relation between rheumatoid arthritis and indices of exposure, having allowed for potential confounders of smoking, employment in the coal mining industry, and number of pregnancies., Results: 58 Cases of rheumatoid arthritis (43 men, 15 women) were identified. Cases had significantly shorter duration of exposure than referents. There was no significant difference between cases and referents in mean silica concentration. Men who had worked in the coal mining industry were particularly at risk (odds ratio 5.36, 95% confidence interval 1.92 to 15.03)., Conclusion: There was no evidence of increased risk of developing rheumatoid arthritis after occupational exposure to silica at mean exposures within the current United Kingdom exposure limits.

Purpose: To restore the anophthalmic socket, primarily or secondarily, using a hydroxy-apatite sphere (HA)., Methods: We used HA in 33 patients (25 male, 8 female), aged from 4 to 68 years (mean 38.1 years) for 19 primary and 14 secondary implantations. HA spheres measured 16 mm in one patient, 18 mm in 21 and 20 mm in 11. The spheres were wrapped in donor sclera preserved in absolute alcohol. All six extraocular muscles were isolated, in the cases where this was possible. Buccal membrane was grafted in three patients to restore the fornices. Drilling was done on four patients using a 3.8 serrated plastic sheath., Results: During follow-up of 7-69 months we observed no complications except for slight edema in the immediate postoperative period. All patients gained very good to excellent motility of the implant, acceptable symmetric appearance in the case of primary implantation, and a dramatic improvement of facial appearance in the case of secondary implantation., Conclusions: HA spheres are an excellent orbital implant for primary and secondary restoration of the anophthalmic socket causing no serious complications.

The availability of improved ceramic materials, bonding techniques, new technology and issues of amalgam safety have led to a revival of interest in ceramic inlays in dentistry over the past ten years. Clinical studies have been carried out during this time using various evaluation techniques to assess the clinical performance of these restorations. In this paper, recent clinical studies are examined and a review of the current state of knowledge regarding the clinical performance and survival statistics of ceramic inlays is presented. The major problems associated with ceramic inlay therapy appear to be fracture, hypersensitivity, degree of fit, maintenance of marginal integrity, microleakage, bond failures and cement wear. Other areas which also affect the clinical performance of ceramic inlays are ceramic wear, opposing tooth wear, plaque accumulation, gingivitis, secondary caries, colour stability, anatomic form and radiopacity. Recommendations based on the findings of clinical studies are also presented and whilst no specific material or technique has been shown to be clearly superior, certain principles which predispose to success can be identified. When compared with other forms of aesthetic intracoronal restorations, ceramic inlays perform well. However, their high cost and extreme technique sensitivity would appear to restrict their use to certain limited clinical situations.

To evaluate biocompatibility to tissue in long-term implantation, Bioceram discs made of aluminum oxide (Al2O3) were implanted subcutaneously within the interscapular region of 64 rats for six to 20 months. Histological sections stained with haematoxylin and eosin (H&E) and the surface of the implant material were observed using light microscopy. Different cell types and the thickness of fibrous capsules surrounding the implants were examined quantitatively by light microscopy. Small numbers of macrophages (2.8 +/- 0.7%) and lymphocytes (2.7 +/- 0.9%) were observed at six months after implantation, gradually decreasing to zero at 16, 18 and 20 months. Neither neutrophils nor foreign body giant cells were seen in any specimens. The thickness of fibrous capsules surrounding the implants was closely related to the shape of the implant, but there was no significant change between six and 20 months after implantation. No change in Bioceram surfaces were observed under stereoscopic microscopy from six to 20 months after implantation. The study results indicate that Bioceram is a satisfactory biocompatible material for reconstructive surgery from the viewpoint of long-term tissue response. Present results of experiments with Bioceram are also compared to previous results with Apaceram and different tissue responses of the two materials are discussed.

Objective: To evaluate crystalline silica as a human carcinogen., Methods: A cohort of 5115 men, born 1916-45 and employed in the pottery, refractory, and sandstone industries of Stoke-on-Trent was identified from occupations subject to health surveillance by the local Silicosis Medical Board (now the Department of Social Security). Detailed occupational and smoking histories, and records of small parenchymal opacities on periodic radiographs were extracted from medical records. An exposure matrix was derived from some 1400 personal or static dust samples and tested against the presence of small parenchymal opacities in a subcohort of 1080 men employed for at least 10 years, who had started working in the industry before 1960., Results: Standardised mortality ratios (SMRs) calculated against mortalities for Stoke-on-Trent, with 95% confidence intervals (95% CIs), were raised for all causes (1.15 (1.05 to 1.26)), lung cancer (1.28 (0.99 to 1.62)) and non-malignant respiratory disease (2.04 (1.55 to 2.65)). Average concentration and duration of exposure to silica were, taken together, significantly related to the presence of small opacities (> or = 1/0). In a nested case-referent analysis of 52 cases of lung cancer and 197 matched referents, conditional logistic regression gave a significantly increased odds ratio (OR) for average silica concentration (micrograms/m3.100), after adjustment for smoking, of 1.66 (1.14 to 2.41) but not for duration of exposure nor, in consequence, for cumulative exposure., Conclusion: The association between risk of lung cancer and quantitative estimates of silica exposure supports the SMR analysis and implies that crystalline silica may well be a human carcinogen.

The discs of synthetic auditory ossicle (Bioceram), which are composed of aluminium oxide (Al2O3), were implanted subcutaneously in the interscapular region of 16 rats. The implanted specimens were removed at 1, 3, 7 and 14 days after implantation. The decalcified 6 microns thick sections were stained with H.E. and cell types around the implants were counted microscopically. We found that an acute inflammatory reaction occurred at one day, in which macrophages and neutrophiles predominated, and almost disappeared at about 7 days after implantation. Fibrosis began to be observed at 3 days. During this early stage, foreign body giant cells were found in only one specimen at 3 days. These findings, in comparison with those in the controls, showed that the chemical irritation of Bioceram to the subcutaneous tissue is slight, although the physical and/or chemical irritation of Bioceram lasts continuously and induces fibrosis around the bioimplant. The results so far suggest that Bioceram seems to be a satisfactorily biocompatible material, at least within the extent of 2 weeks.