Ceramic Fracture Research Articles

Comparison of Shear Bond Strength of Silorane and Methacrylate-Based Composites to IPS Empress 2 Ceramic with Various Surface Treatments

Objectives Treatment of chipped or fractured porcelain with composite resin is considered as an economic treatment for minor fractures in ceramics. The aim of this study was to evaluate the effect of different ceramic surface treatments on bond strength of methacrylate-based and silorane-based composite resin to IPS Empress 2.Methods Sixty IPS Empress 2 ceramic discs were fabricated and after etching with 9.6% hydrofluoric acid, they were divided into six groups:(1) P90 primer and bonding agent + Filtek P90 composite resin; (2) Single Bond + Filtek Z250 composite resin; (3) similar to the first group+ silane pretreatment; (4) similar to the second group + silane pretreatment; (5) silane pretreatment + Filtek P90 composite resin; (6) silane pretreatment + Filtek Z250 composite resin. Each specimen was subjected to shear load until fracture occurred. Statistical analysis was performed using one-way ANOVA, Tukey’s test and t-test.Results Regardless of the type of surface treatment, Z250 composite demonstrated significantly higher shear bond strength than P90 composite (P < 0.05). Group 4 showed the highest shear bond strength values with statistically significant difference with other groups while the fifth group showed the least values (P < 0.05).Conclusion Silane coating along with the application of adhesive system and etching in methacrylate-based composite was the most efficient surface treatment in terms of bond strength.

FIVE YEAR OUTCOMES OF CERAMIC-ОN-CERAMIC AND CERAMIC-ОN-POLYETHYLENE BEARINGS IN HIP JOINT REPLACEMENT

In view of the increasing number of hip joint replacement volume there remains the key issue of improving prosthesis survivorship which directly depends on the friction couple. Material and methods. The authors have analyzed five year outcomes of two bearing types (head and insert) used in hip replacement: ceramic-on-ceramic (CoC) in 324 patients and ceramic-on-polyethylene (CoP) in 300 patients. Totally 550 patients were operated in the period starting 2010 till 2014, including 74 patients underwent bilateral hip replacement. The authors divided patients based on gender and also into three age groups: 20-40, 41-60 and 61-80 years old. The largest group comprised 156 women aged 41-60 years (28.4%). Additional grouping of patients was made based on gender, age and bearing diameter.36 mm diameter bearing was characterized of the most frequent use. Functional outcomes were assessed by Harris Hip Score. Statistical analysis was made with Statistica 10 software. Statistical significant was observed at p0.05.Results.28 mm diameter bearing were rarely (19.5%) applied and mainly in women which is related to need for use of smaller acetabulum components and inability to implant a larger insert.36 mm diameter bearing were used most frequently, CoC articulation of36 mm was used in men in 34% of cases and in women – in 18.12% of cases.40 mm articulations were implanted in women two times less than in men which is related to a smaller diameter of acetabulum in women. Generally, CoC bearings were implanted more often in men which can be explained by a bigger social demand as well as a higher anti-luxation stability of large diameter bearings. Dislocations of implants occurred in 5 (0.91%) patients: in 4 patients with CoP bearingand in one patient with CoC articulation. Four revision procedures (0.64%) were made due to deep periprosthetic infection: two surgeries in each group. Harris Hip Score evaluation in CoC group demonstrated excellent and good outcomes in 99.2% of cases, and in CoP group – in 97.5% of cases.Conclusion. The authors observed no ceramic fractures or acoustic effects during 60 months follow up. It’s reasonable to increase CoC bearing diameter to achieve a better anti-luxation effect. CoC bearing selection should depend on patient’s activity and social demands but not only on the age. Based on study observations the authors forecast a higher survivorship of CoC couple within 15-20 years and expect to prove this conclusion in further studies.

Long-Term Results of Cementless Total Hip Arthroplasty Using a Modular Stem in Patients with Femoral Head Osteonecrosis

Patients with femoral head osteonecrosis are younger and more active than those with osteoarthritis of the hip. More than 10-year results of total hip arthroplasty (THA) using modular cementless stem in osteonecrotic patients have not yet been reported. We determined clinical and radiologic results of cementless modular stem in a consecutive series of patients with femoral head osteonecrosis a minimum follow-up of 10 years. We retrospectively reviewed 48 patients (58 hips) who underwent THA for femoral head osteonecrosis with a cementless modular femoral stem. Metal-on-metal articulation was used in 32 hips and ceramic-on-ceramic articulation in 26. There were 26 men and 22 women with a mean age of 52 years at the time of the operation. These patients were followed for 10 to 15 years. All of the acetabular cups and femoral stems had radiographic evidence of bone ingrown stability at the final follow-up. Three hips were revised due to infection. There were no revisions for ceramic fracture or adverse reaction to metal debris. The survival rate was 94.8% (95% confidence interval: 89.8–100%). However, 12 patients (12 hips, 21%) suffered thigh pain. In six patients (six hips), the pain disappeared within 1 to 2 years, whereas the pain persisted until the final follow-up in the remaining six patients. As of 10 to 15 year, radiologic results and survival of THA using a modular femoral stem were good in patients with osteonecrosis. However, the incidence of thigh pain remains a matter of concern.

Circumferential Ceramic Liner Fracture in a Squeaking Hip

Circumferential Ceramic Liner Fracture in a Squeaking Hip

Failure analysis of ceramic tool in intermittent turning of hardened steel

The aim of this investigation is to identify the Al2O3-(W, Ti)C ceramic fracture modes and failure mechanisms under different cutting speeds and feed rates during intermittent turning of hardened 20CrMnTi steel. The failure surfaces of the cutting tools were examined by digital optical microscope and scanning electron microscope. The cutting forces and transient temperature in the intermittent turning process were measured during the entire life cycle. The experimental results showed that the cutting forces exhibited an increasing trend with the tool failure progression, which in turn accelerated the tool failure progression. The main failure modes of ceramic tools were wear and micro-chipping in the initial stage and final fractures, resulting from mechanical damage and thermal damage in intermittent turning processes. And the cutting temperature increased with the increase in cutting speed. The cutting speeds and feed rates were closely correlated with ceramic tool fracture modes and failure mechanisms. Furthermore, the combination of cutting parameters was divided into four regions with different fracture modes and failure mechanisms of cutting tools according to the fracture morphology of cutting tools. This partitioning analysis can provide a basis for the design and development of different ceramic cutting tools with the desired properties for different applications.

Partial exchange in total hip arthroplasty : What can we combine?

In case of hip revision arthroplasty, one component (cup/stem) is often well fixed and does not need to be exchanged. The newly implanted component needs to be compatible with the well-fixed implant. The combination of implants from different companies leads to "mix and match" or even mismatch between the implants. The objective of this work was to describe possible combinations including their specifications that need to be considered in partial exchange of hip prostheses. For this purpose the literature, surgical techniques of companies and judgements concerning this topic were analysed and our own results and experiences were included. Partial revision arthroplasty can be challenging and needs to be planned in detail. In case of isolated cup or inlay revision with exchange of amodular head the cone of the stem needs to be identified. Aceramic head may be used in revision with atitanium sleeve even from adifferent company as long as they are compatible. Patients however need to give their informed consent for this mix and match procedure. This procedure is done frequently and good study results support this, however from a juristic point of view a definite recommendation cannot be given. If the inlay of acup is replaced, the original inlay should be used. If this is not available anymore, it can be manufactured as aspecial product in many cases. If this is also not possible, an inlay can also be cemented into awell-fixed cup. Biomechanical and clinical studies support this off-label technique. In case of an isolated exchange of the stem with aceramic inlay that is retained in awell-fixed cup, the revision stem and ceramic head need to be from the same company as the cup. In case of ceramic fracture, aceramic head with atitanium sleeve should be combined with aPE or ceramic inlay, ametal head or inlay should never be used.

Inelastic Response and Energy Dissipation in Ceramics using Deshpande and Evans Constitutive Model

Development and characterization of armour response under impact is an important aspect in defence sector. Responses of ceramics to impact loads are usually obtained by experimental method due to difficulties in evaluating material properties at high strain rate. However, experiments while yielding reliable information about structural response suffer from uncertainties from shape and size effects. Hence, combination of numerical simulation with experimental characterization of material parameters provides an efficient solution to the problem. The difficulties encountered in incorporating the exact failure mechanism under compression in ceramics eventually led to different phenomenological models based on empirical mathematical expression wherein material parameters are determined based on carefully conducted experiments. Even though, the phenomenological model developed by Johnson and Holmquist (1999) does not consider the micro-structure of ceramics and its material properties such as toughness and hardness, many aspects of ceramics inelastic deformation are simulated accurately when the material properties are calibrated according to this model.In micro mechanics based models, the physical aspect of the compressive failure of ceramics including the crack initiation from initial flaws and crack propagation under different stress states have been considered to study the failure pattern of ceramics. Recently, a micro mechanics based constitutive model was proposed by Deshpande and Evans (2008) for characterizing the inelastic deformation and fracture of ceramics accounting for combined influences of micro-crack growth and plastic slip. In the present work, the Deshpande Evans (DE) model is implemented in commercial software ABAQUS to compute the inelastic deformation and fracture in ceramics. The model has been validated by solving standard benchmark problems. The inelastic deformation and energy dissipation in ceramics with metal backings are also studied under high velocity impact.

Experimental Analyses for The Mechanical Behavior of Pressed All-Ceramic Molar Crowns with Anatomical Design

Ceramic restorations show considerable variation in strength and structural reliability regarding to the type of material, and design characteristics. The fracture of ceramics occurs with little or no plastic deformation, with cracks propagated in an unstable manner under applied tensile stresses. The aim of the study was to assess experimental analyses of pressed monolithic ceramic crowns with anatomical design used in the posterior areas in order to understand their mechanical behavior before following their clinical use. Experiments were conducted on a complete molar crown preparation. Experiments show different modes of fracture for the tested samples. Digital images from the fractured pieces of the crowns were used to verify the fragments in all cases final fracture occurred by splitting into two and often more parts. The graphically representation of the displacement depending on the load highlights a series of peaks that can be correlated with cracks occurred in crowns. The development of well-designed mechanical experiments could be useful to help to predict clinical survival of these new all-ceramic restorative techniques and materials. Because failure is often accompanied by complete cracking of the crowns, preliminary research should represents a compulsory goal.

Long Term Survivorship of a Severely Notched Femoral Stem after Replacing the Fractured Ceramic head with a Cobalt-Chromium Head.

Background:Although ceramic head fracture occurs infrequently today, in the event of a fracture, the resulting revision surgery can prove very challenging, since the ceramic particles lodge into the surrounding soft tissue and can cause rapid implant failureCase Presentation:A case of long term survivorship of a severed notched femoral stem after replacing the fractured femoral head with a cobalt-chromium one is reported in a 40-year old woman with hip dysplasia who underwent an uncomplicated total hip arthroplasty. The incident of ceramic femoral head fracture occurred 14 months postoperatively without reporting any significant trauma. Intraoperative findings at revision were a multifragmented femoral head and a damaged polyethylene insert along with diffuse metallosis and excessive wear of the cone of the stem. Both the stem and the acetabular component were stable. After removal of ceramic fragments, metallotic tissue excision and careful lavage of the joint, the inlay was replaced by a similar one and a cobalt-chromium femoral head was placed to the existing notched taper of the firmly incorporated stem. At the 13th year follow up examination, the patient had no pain, used no walking aids, and had normal activity with no signs of wearing or loosening in the plain x-rays.Conclusion:Despite current recommendations of using ceramic femoral heads in cases of fracture or to revise the severely damaged stems we were able to provide a long term survivorship up to 13 years postoperatively of a cobalt-chromium femoral head applied to a severe damaged stem.

Physical and mechanical properties of a novel hydrogen transport membrane

A novel cermet (ceramic/metal composite) hydrogen transport membrane (HTM) was characterized for its physical and mechanical properties at both room temperature and at elevated temperature of 850 °C. The density of the HTM cermet was measured as 8.9 g/cm3 at ambient temperature with dynamic Young’s modulus of 145.5 GPa and the dynamic shear modulus (G-value) of 54.29 GPa, whereas the Poisson’s ratio (υ) is calculated to be 0.34. Vickers hardness numbers for the as-received HTM cermet are constant and in the range of 2.0–2.2 GPa, with the change of loading force from 100 to 1000 g. The flexural strength (σ fs) of the HTM cermet is about 356 MPa at room temperature and decreases to 284 MPa at the elevated temperature of 850 °C in both air and nitrogen. A difference in testing atmosphere (air or N2) had insignificant effect on the load–displacement curves during the flexural strength test at the elevated temperature of 850 °C. From the load–displacement curves, HTM cermet behaves much more like elastic material at room temperature; with the temperature increased to 850 °C, its behaviour is much more like a metallic material with fractures preceded by plastic deformation. The initial yielding strength of HTM could be mainly controlled by the yield strength of the soft Pd metal material, and the zirconia fractures before yielding in Pd at room temperature, whereas at 850 °C, the yield stress of the Pd drops dramatically and allows it to work and harden in the constraint of a rigid ceramic. The final failure load is mainly dictated by ceramic fracture, while the initial yielding stress is determined on the yield strength of the soft Pd metal at both room temperature and the elevated temperature of 850 °C.

Choosing a Femoral Head: A Survey Study of Academic Adult Reconstructive Surgeons

BackgroundOur aim was to examine how academic adult reconstructive surgeons have interpreted evidence on femoral head material in total hip arthroplasty (THA). MethodsA 16-question survey to evaluate attitudes toward ceramic and cobalt-chrome head use was emailed to 274 faculty at 42 US adult reconstruction fellowship programs. ResultsWith 116 respondents, the response rate was 42.2%. Faculty use ceramic heads 72.9% of the time. The most common reason why respondents do not use ceramic heads is cost (44.8%). Ninety-four percent of faculty have observed head-neck taper corrosion in cobalt-chrome on polyethylene THA, while 9.5% of faculty have observed head-neck taper corrosion in ceramic on polyethylene THA. Only 6.0% of surgeons have seen Biolox Delta ceramic fracture. ConclusionAdult reconstruction thought leaders are guided by evidence suggesting that with ceramic heads, taper corrosion and fracture are rare. Cost and personal experience also strongly influence their implant selection. Efforts to equalize cost of ceramic and cobalt-chrome heads may free surgeons to practice in a purely evidence-based fashion.

Stem taper mismatch has a critical effect on ceramic head fracture risk in modular hip arthroplasty

BackgroundModular total hip prostheses with ceramic heads are well established in orthopedic surgery and widely used. With the variety of different manufacturers and available designs, components are at risk for mismatch. Several case studies show the potentially devastating effects of mismatch. MethodsThe aim of this study was to investigate the outcome of one arbitrary component mismatch with commercially available components that appear to provide a stable fixation during assembly. A biomechanical in-vitro analysis of fracture strength (n=5) was carried out in accordance with ISO 7206-10. “Type1” Bi-Metric®-stems were mismatched with “V40” Al2O3 ceramic heads. FindingsMean fracture strength was reduced to about 50% of the recommended FDA minimum by the mismatch (Mean 23.68kN, SD 2.35kN). A small contact area between head and stem taper was identified as a potential key parameter. InterpretationMixing and matching components can put a patient at greater risk for ceramic head fracture and must be avoided.

Femoral head–neck modularity: Curtain calls and caveats

There are practical and fiscal benefits of head–neck modularity. Taper corrosion occurs with all head sizes and rarely necessitates revision. The role of design and manufacturing variables continues to be investigated and debated. The utilization of ceramic heads has increased but the cost–utility ratio needs scrutiny. Changes in surgical practice, including smaller incisions and the increased use of cementless, tapered titanium stems are challenges to consistent and adequate taper assembly. Surgical taper assembly is variable and important regardless of the head material. Standardization of surgical taper assembly is desirable for all head materials: taper assembly has been implicated in ceramic head fracture as well as in fretting and corrosion.

Incidence of Ceramic Liner Malseating After Ceramic-on-Ceramic Total Hip Arthroplasty Associated With Osteolysis: A 5- to 15-Year Follow-Up Study

BackgroundThe aim of our study was to evaluate the clinical and radiographic outcomes of malseating of the acetabular liner in ceramic-on-ceramic total hip arthroplasty (THA). MethodsOutcomes for 160 ceramic-on-ceramic THAs, contributed by 116 women and 39 men, were evaluated. Clinical and radiographic measurements were obtained over a 5- to 15-year follow-up for analysis. ResultsLiner malseating was identified in 20% of cases. Outcomes for 32 cases with liner malseating (group A) were compared to outcomes for 128 joints with correct liner seating (group B). The Harris hip score at the last follow-up was 90.1 for group A and 89.6 for group B. Osteolysis was identified in 5 cases in group A (15.6%), compared to 3 cases in group B (P < .001). No significant between-group differences were identified with regard to ceramic fracture, audible squeaking, loosening of components, and revision THA. The mean annual liner wear rate was comparable between groups, 0.0045 mm/y for group A and 0.0039 mm/y for group B. The 10-year Kaplan-Meier survivorship, based on an end point of revision THA, was 100% for group A and 99.0% for group B. ConclusionOver a moderate-length follow-up of 5-15 years, malseating of the acetabular liner was not associated with negative clinical outcomes or THA survivorship. Malseating did increase the incidence of osteolysis, a risk factor for adverse effects. Long-term follow-up studies are needed to fully quantify the effects of malseating of the acetabular liner.

Compatible CAD-CAM titanium abutments for posterior single-implant tooth replacement: A retrospective case series

Statement of problemIn addition to the original abutments provided by implant companies, compatible computer-aided design and computer-aided manufacturing (CAD-CAM) abutments are also available from different manufacturers. However, the combination of abutments and implant systems from different manufacturers may lead to mechanical problems between components. Little has been reported on the clinical performance of this treatment option. PurposeThe purpose of this retrospective case series was to evaluate the outcome of compatible CAD-CAM titanium abutments (TiAs) for posterior single-implant tooth replacement (PSITR) up to 6 years after insertion. Material and methodsEighty-one patients (34 men, 47 women) who received PSITR restored with compatible CAD-CAM TiAs and had a final recall examination between May 2014 and April 2015 were included in this study. Clinical and radiographic examinations were documented. Retrospective evaluation of the patient records was also performed. Correlations between bone-level changes and variables were calculated using the Spearman correlation. ResultsImplant and prosthesis survival rates were 100%. Twenty technical complications were observed, including 9 decementations of the crown, 6 screw loosenings, and 5 ceramic fractures. Periimplant mucositis was diagnosed in 36 patients (44.4%) and periimplantitis in 6 patients (7.4%). Correlation analysis showed a significant effect of the extent of periodontal bone loss of the remaining teeth on the marginal bone-level changes around implants (r=0.548, P<.001). ConclusionsCompatible CAD-CAM TiAs provide a viable treatment option for PSITR. However, in light of relatively high screw-loosening and decementation rates, choosing appropriate cements and abutment manufacturers is essential to improve the clinical performance of this treatment option.

Fracture of Ceramics with Different Conical Indenters: Edge Chipping

Mechanical tests for evaluating the fracture resistance of ceramics on chipping rectangular specimen edges were first performed with conical diamond indenters of 11–800 μm tip radii. In the experiments elastic silicon-nitride Si3N4 ceramics and inelastic zirconia TS ceramics, displaying a phase transition on fracture, were used, soda lime glass served as the object for comparison. The fracture resistance of those materials was shown to increase similarly when the above indenters are employed. Chip scars formed on the specimen edges of Si3N4 ceramics do not actually differ from those observed in glass tests (pseudoconical, nail-like, arbitrary). With an increase in the tip radius, the first ones grow in number. It does not take place in the tests of TS ceramics. Comparative fracture resistance estimates obtained with the edge chipping method using different fracturing tools were established to be invalid.

Ceramic-on-ceramic bearings total hip arthroplasty in young patients.

BackgroundThe results of ceramic-on-ceramic (CoC) total hip arthroplasty (THA) in younger patients were not univocal. This study aims to evaluate the results of CoC bearing THA in patients younger than 50 years.MethodsA total of 90 younger patients performed CoC THAs during March 2003 and May 2008 were included in this study. Hip function and activity were evaluated with Harris hip score and University of California Los Angeles activity score. We had discussed survival rates, radiological findings of component loosening or osteolysis, and ceramic-related complications in these patients.ResultsThe mean Harris hip score increased from 46.3 ± 12.0 points (range, 28-70 points) before surgery to 92.5 ± 5.6 points (range, 78-100 points) at the final follow-up. The mean preoperative University of California Los Angeles activity score was 4.2 ± 1.1 points (range, 2-6 points), which improved to a mean of 7.2 ± 1.3 points (range, 4-10 points). At the time of the last follow-up, there was found to be 1 occurrence of hip dislocation, 1 squeaking, and 2 “sandwich” ceramic liners fractured during normal activity of daily living. No hips showed osteolysis or required revision for aseptic loosening. Kaplan-Meier survivorship with revision due to loosening or osteolysis was 100% and with revision due to ceramic fracture was 97.3% (95% confidence interval, 93.7%-100%) at a mean of 9.4 years.ConclusionsThis study with the use of CoC bearings THAs in younger patients have shown promising results and higher rate of survivorship without evidence of osteolysis.

Primary Total Hip Arthroplasty With Fourth-Generation Ceramic-on-Ceramic: Analysis of Complications in 939 Consecutive Cases Followed for 2-10 Years

BackgroundDelta ceramics may be the bearing of choice for younger and active patients due to its improved toughness and wear characteristics, provided there is no risk of fracture. However, ceramic fracture is the most serious complication related to this type of bearing. Although millions of Delta ceramics have been implanted worldwide, short to midterm results have been scarcely reported in the literature. The purpose of this study was to report the complication rate at short to midterm follow-up associated with the bearing surface used in a series of primary total hip arthroplasties with Delta ceramic-on-ceramic bearings performed in a single institution. MethodsA total of 939 cases (880 patients) undergoing primary total hip arthroplasty with fourth-generation Delta ceramic-on-ceramic bearings were retrospectively reviewed. They were followed for an average of 5.3 years (2-10 years). ResultsOne hip experienced a liner fracture, 2 cups presented early loosening due to friction between the acetabular screw and the backside of the liner, one femoral ball head had a fracture; one case of squeaking was reported, which is impending revision. Considering revision or impending revision in relationship with the bearing surface as the end point, the mean survival rate was 99.3% (confidence interval 95%, 98.3%-99.7%) at 2-10 years. ConclusionThis study showed a low rate of ceramic fracture compared with others; however, it was much higher than the complication rate presented by the manufacturers. The complications observed were directly related to technical errors that surgeons should avoid when using this type of surface.

Revision of ceramic fracture with ceramic-on-polyethylene in total hip arthroplasty: Medium-term results

There is no consensus on the bearing of choice in revision for ceramic fracture after total hip arthroplasty (THA). The aim of this study was to evaluate the outcomes using ceramic‐on‐polyethylene (CoP) articulation in revision for ceramic breakage. Twelve patients who underwent revision hip surgery between 2002 and 2013 were followed-up. Appropriate surgical technique, including accurate synoviectomy, was used. The cup and the head were changed in four patients and only the liner and the head were replaced in the remaining eight patients. At the final follow-up there were no cases of re-revision due to tribological reasons, and only one case of polyethylene (PE) wear and osteolysis was scheduled for a new revision because of clear cup malposition. Complications were four cases of dislocation, one case of loosening and one case of infection. Revision of fractured ceramic is a challenging situation with a high risk of early complications. Using CoP liners with accurate synoviectomy and correction of misalignment can be considered a valuable bearing option at medium‐term follow-up.

Evidence of Normal to Anti Ferroelectric Phase Transition of PLZT Transparent Ceramics of Different Zr/Ti Ratio

The lanthanum-modified lead zirconate titanate transparent ceramics with different Zr/Ti ratio were prepared by the hot pressing sintering method. A single perovskive structure with a dense microsctructure was obtained and the transgranular fracture of PLZT ceramics tended to be more serious As the Zr/Ti ratio increases, the transmittance of PLZT ceramics tended to be higher and the transgranular fracture became more serious. The P-E loops changed froe a square hysteresis loop to a double tending slim hysteresis loop. Besides,the S-E loops changed from a approximate parabolic shape to a butterfly shape. These two loops confirm the transition from normal ferroelectric to anti ferroelectric phase occured with the Zr/Ti ratio increasing.