Conventional Titanium Research Articles

Microstructure, phase composition and hardness of Ti–Au cladding deposited on Ti–6Al–4V substrate by electron beam powder bed fusion method

In this study, a Ti–Au cladding was deposited on a substrate from the Ti–6Al–4V alloy by the electron beam powder bed fusion method in a vacuum. The main goal was to assess the possibility of using titanium powders and gold foils as a feedstock for additive manufacturing of such dental products. The microstructure, chemical element distributions, phase composition and hardness of the formed Ti–Au alloy were studied using optical microscopy, energy dispersive X-ray analysis, as well as X-ray diffraction and nanoindentation tests. Gold-containing intermetallic compounds were observed through the entire cladding thickness. The α-Ti, α-Au, AuTi and AuTi3 phases were found, in addition to the Ti3Au one, which provided hardness values greater than those of conventional titanium alloys. It was shown by results of the crystal-geometric and X-ray phase analysis that the AuTi3 phase possessed the most densely packed A15 structure. This fact correlated with the obtained data on the deviation of the atomic volume per ion from Zen's law and the high hardness levels. Metallurgical patterns of the microstructure formation that affected the functional properties of such claddings were discussed and a further research direction was proposed.

Histomorphometric and biomechanical evaluation of the osseointegration around micro- and nano-level boron-nitride coated titanium dental implants

IntroductionTitanium dental implants has been coated with different materials such as polymers and biomimetic agents, bone morphogenetic protein, calcium phosphate to enhance surface properties of the titanium implants for osseointegration. The aim of this study was to evaluate the bone tissue healing around Boron Nitride-coated (BN-coated) titanium implants histomorphometrically and biomechanically and also observe the effect of different coating thicknesses on osseointegration. Materials and methodsBN was coated on dental titanium implants with two different coating thicknesses by using RF magnetron sputtering system. Totally fifty-four implants were inserted into the tibias’ of 12 New Zealand rabbits bilaterally under general anesthesia. All animals were sacrificed after 4-weeks. Bone-implant contact (BIC) and new bone area/total area ratios (BATA) were calculated. Also, the removal torque (RT) test was performed. ResultsThe highest new bone area in the medullary cavity was around the nano-BN-coated surface with 15.70%. In micro-BN-coated surface and control group, this ratio was determined as 10.48% and 8.23%, respectively. The BIC ratios in upper-side of implants and cortical-associated BIC ratios in lower-side were found significantly higher in control and micro-BN-coated group than nano-BN-coated group (p < 0.05). Similar BIC values were observed between control and micro-BN-coated groups (p > 0.05). BATA values did not show statistically significant differences between all three groups (p > 0.05). The RT values measured in all groups were found comparable and no statistically significant differences were found (p > 0.05). ConclusionNo inflammatory reaction developed around any implant. Relatively more new bone formation around nano-BN-coated titanium implants indicates the promising osseoinductive effect of BN coating. BN-coated implants showed similar biomechanical and histomorphometrical outcomes to that of the conventional titanium implants through a 4-week evaluation period.

Minimum 2-year results of the second-generation CFR-PEEK locking plate on the proximal humeral fracture.

The aim of this study was to analyse and compare the 24-month range of motion results of patients treated with CFR-PEEK2 versus conventional titanium plate osteosyntheses (TAL-P). We hypothesized similar clinical outcomes but a better range of motion in the CFR-PEEK2 group than the TAL-P group in the 2-year follow-up. This retrospective study analysing prospectively collected data included all patients that presented with a PHF and were treated with CFR-PEEK2 between November 2016 and April 2018. Follow-up was performed after a minimum of 24months, evaluating the functional degree of movement functional scores, including the Subjective Shoulder Value (SSV) as well as an age- and sex-adapted Constant-Murley score (CMS). The 2-year results were compared to the results of a matched pair group comprising patients that were treated with TAL-P during the same period. Of the 35 patients included (mean age: 61.2 [18-78] years), 30 (86%) patients completed the 24-month follow-up in the CFR-PEEK2-group. After 24months, the mean CMS was 89.9 points (pt) (44.5-100 pt) and the mean SSV was 86.7% (35-100%). Compared to the matched-pair TAL-P cohort, the 24-month follow-up showed similar results (CMS: 88.6 pt. (40.5-100 pt.) [p = 0.9]; SSV: 76% (30-100%) [p = 0.05]). However, significantly better degrees of forward flexion and internal rotation as well as a better range of motion in abduction was recorded in patients treated with CFR-PEEK2 plates than TAL-P. At the 24-month follow-up, patients who received treatment with CFR-PEEK2 compared to those that received TAL-P showed enhanced range of motion whilst having similar clinical scores.

Outcomes of cervical degenerative disc disease treated by anterior cervical discectomy and fusion with self-locking fusion cage.

BACKGROUNDCervical degenerative disc (CDD) disease is a common type of spondylosis. Although anterior cervical discectomy and fusion (ACDF) is the preferred treatment for CDD disease, internal fixation with a titanium plate may cause various complications. The invention of the ACDF with a self-locking fusion cage (ROI-C) has effectively decreased the incidence of postoperative complications. AIMTo observe the outcomes of CDD disease treated by ACDF with a ROI-C.METHODSNinety patients with CDD disease treated at our hospital from March 2019 to March 2021 were included. They were divided into two groups (control group and observation group, n = 45 in each) using a random number table. Patients in the control group received ACDF plus internal fixation with a titanium plate. Those in the observation group received ACDF + ROI-C placement. The two groups of patients were compared in terms of surgical parameters, pain, cervical spine function, range of motion, and complications.RESULTSThe two groups of patients showed no significant differences in surgical time, blood loss, drainage volume, and length of hospital stay (P > 0.05). No significant differences in the visual analogue scale (VAS), Japanese Orthopedic Association (JOA), and neck disability index (NDI) scores were observed between the two groups before surgery (P > 0.05). The VAS and NDI scores in the observation group were considerably lower than those in the control group after surgery; however, the JOA scores in the observation group were significantly higher than those in the control group (P < 0.05). No significant differences were observed in cervical disc height and the range of motion of the superior or inferior adjacent vertebrae between the two groups before surgery (P > 0.05). The disc height in the observation group was larger than that in the control group after surgery. The range of motion of both the superior and inferior adjacent vertebrae was significantly smaller in the observation group than in the control group (P < 0.05). The incidence of complications was only 2.22% in the observation group compared to 15.56% in the control group, and the difference was statistically significant (P < 0.05).CONCLUSIONCervical spine function restoration was better with ROI-C with internal fixation in ACDF than with conventional titanium plates in ACDF for CDD disease.

Application of multi-directionally forged high-strength titanium to dental implants in beagle dogs.

Pure titanium is widely used as a material in dental implants. However, it possesses inferior mechanical strength. This study aimed to elucidate the efficacy of acid treated multi-directionally forged (MDF) pure titanium in vivo. We verified the temporal changes until osseointegration in beagle dogs. Using two types of experimental materials (conventional pure titanium or MDF pure titanium), new bone formation was assessed using morphological examinations, and the bone-to-implant contact (BIC) value was evaluated at each time point (14, 30, and 90 days after the operation). As such, new bone formation was observed around the acid-etched MDF group, in which the BIC value was highest, followed by that in the acid-etched pure titanium group. MDF pure titanium implants showed early promotion of new bone formation compared to conventional titanium implants. The new acid-treated MDF made of pure titanium could be applied to humans in the future to prove its practicality.

Tantalum Versus Titanium Acetabular Cups in Primary Total Hip Arthroplasty: Current Concept and a Review of the Current Literature.

Primary total hip arthroplasty (THA) is becoming an increasingly popular and efficacious medical procedure. There have been a number of studies evaluating tantalum acetabular cups compared with the conventional titanium acetabular cups for use in total hip arthroplasties. We conducted a systematic review and summarize clinical studies comparing tantalum acetabular cups with the conventional titanium acetabular cups for use in primary total hip arthroplasties. A literature search was performed to find all relevant clinical studies until March 2020, which then underwent a further selection criteria. The inclusion criteria was set as follows: Reporting on human patients undergoing primary total hip arthroplasty; Direct comparison between tantalum acetabular cups with conventional titanium acetabular cups for use in primary total hip arthroplasty; Radiological evaluation (cup migration, osteointegration); Clinical (functional scores, need for subsequent revision, patient-reported outcomes; Post-operative complications; Reporting findings in the English Language. After a thorough search a total of six studies were included in the review. The primary outcome measures were clinical outcomes, implant migration, change in bone mineral density and rate of revision and infection. Tantalum is superior to titanium with regards to fewer radiolucencies, 100% survivorship at 12 years post-operatively, improved long-term implant osteointegration and survivorship as well as decreasing osteolysis and mechanical loosening. There has been no significant difference in radioisometric analysis, bone mineral density or Harris Hip Score. Revision and infection rates were found to be significantly lower in tantalum group at 10 years from pooled data of national joint registry (England and Wales), while it was found to be higher in the same at 9 years from pooled data of Swedish and Australian registry although this is not statistically significant. The use of tantalum should be reserved for cases of high risk of failure or mechanical loosening, where failure of a contralateral joint occurred. The use of Tantalum carries lower risk of failure and infection. Further studies with longer follow-up would be useful in drawing further conclusions.

The Performances of Conventional Titanium and Silver-Coated Megaprostheses in Non-oncological and Post-oncological Patients: An Analysis of Infection Failures in 142 Patients.

Megaprostheses are one of the preferred choices of reconstruction after tumor resection. Periprosthetic joint infections are one of the most serious complications of joint prostheses surgeries. In this study, our aim was to analyze the efficacy of silver-coated megaprostheses in reducing the risk of prosthesis-related infection. One hundred forty-two patients who had undergone implantation of a mega-endoprosthesis for non-neoplastic or post-neoplastic conditions were included in this retrospective study. The end-point of the survival analysis was the prosthesis failure due to infection. Thirty-eight patients had undergone implantation of a silver-coated megaprosthesis and 104 patients a megaprosthesis without silver coating. The survival analysis showed an overall infection-free survival rate of 82.3% at five years and 61.9% at 10 years. Silver-coated prostheses had an HR of 0.72 (95% CI: 0.26-2.05; P=0.54). Implantation of a silver-coated mega-prosthesis in non-oncological patients did not significantly reduce the risk of prosthesis-related infection.

In vitro antimicrobial effect of titanium anodization on complex multispecies subgingival biofilm

Anodization is a routine industrial galvanic method that produces a titanium oxide layer on the surface of titanium. Considering the possibility that this technique could influence microbial adsorption and colonization, this in vitro study was conducted to evaluate the impact of a process of anodization applied to a titanium surface on the microbial profile of multispecies subgingival biofilm. Titanium discs produced by using two different processes—conventional and Anodization—were divided into two groups: conventional titanium discs with machined surface (cpTi) Control Group and titanium discs with anodic oxidation treatment (anTi) Test Group. Subgingival biofilm composed of 33 species was formed on the titanium discs that were positioned vertically in 96-well plates, for 7 days. The proportions and the counts of microbial species were determined using a DNA–DNA hybridization technique, and data were evaluated using Mann-Whitney test (p < 0.05). Mean total bacterial counts were lower in Test Group in comparison with Control Group (p < 0.05). Nine bacterial species differed significantly, and were found in higher levels in Control Group in comparison with Test Group, including T. forsythia, E. nodatum, and F. periodonticum. In conclusion, titanium discs with anodization could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm the clinical impact of these findings.

Effect of Ta microalloying on joint performance by tailoring the microstructure during laser beam welding of Ti-22Al-27Nb

The development of Ti2AlNb based alloys has set a strong competition between conventional Ni-based superalloys and titanium aluminides for aerospace industry due to their compatible/superior mechanical properties. With advent of time, progressive manufacturing technologies are being worked out to transform this novel alloy system into tangible engineering products. Laser beam welding (LBW) of Ti2AlNb based alloys is a provocative task due to evolution of metastable B2 phase in the fusion zone (FZ). In the present study, a comparative analysis on LBW of Ti-22Al-27Nb was carried out by preparing the joints with/without an interlayer of Tantalum (Ta) microfilm. The evolution of microstructure in the weld zone (WZ) was analyzed through Electron probe microanalysis (EPMA), Electron backscattered diffraction (EBSD) analysis, High-angle annular dark-field (HAADF), Bright field (BF) and Selected area electron diffraction (SAED) imaging. The effect of Ta on laser beam welded joint (LBWJ) of Ti-22Al-27Nb was established by correlating the room temperature mechanical properties (tensile properties and hardness) with the evolution of phases, grains and grain size distribution and inter/intra grain misorientations in the weld zone (WZ). The addition of Ta into FZ triggered heterogeneous nucleation, causing epitaxial as well as non-epitaxial mode of solidification in the weld pool. A substantial increase in tensile strength of Ta adulterated LBWJ of Ti-22Al-27Nb was the provenance of grain refinement and greater fraction of high angle grain boundaries (64.89%). The tensile strength and percentage elongation of LBWJ prepared with 0.01 mm thin interlayer of Ta was measured up to 1049 MPa (i.e. 99.15% of that of the base material) and 9.53% respectively. Further dilution of the LBWJ with Ta contributed no significant increase in tensile strength due to nucleation of Intermetallics along the periphery of FZ and caused an early failure.

Enhancing osseointegration and mitigating bacterial biofilms on medical-grade titanium with chitosan-conjugated liquid-infused coatings

Titanium alloys, in particular, medical-grade Ti-6Al-4 V, are heavily used in orthopaedic applications due to their high moduli, strength, and biocompatibility. Implant infection can result in biofilm formation and failure of prosthesis. The formation of a biofilm on implants protects bacteria from antibiotics and the immune response, resulting in the propagation of the infection and ultimately resulting in device failure. Recently, slippery liquid-infused surfaces (LIS) have been investigated for their stable liquid interface, which provides excellent repellent properties to suppress biofilm formation. One of the current limitations of LIS coatings lies in the indistinctive repellency of bone cells in orthopaedic applications, resulting in poor tissue integration and bone ingrowth with the implant. Here, we report a chitosan impregnated LIS coating that facilitates cell adhesion while preventing biofilm formation. The fabricated coating displayed high contact angles (108.2 ± 5.2°) and low sliding angles (3.56 ± 4.3°). Elemental analysis obtained using X-ray photoelectron spectroscopy (XPS) confirmed the availability of fluorine and nitrogen, indicating the presence of fluorosilane and chitosan in the final coating. Furthermore, our results suggest that chitosan-conjugated LIS increased cell adhesion of osteoblast-like SaOS-2 cells and significantly promoted proliferation (a fourfold increase at 7-day incubation) compared to conventional titanium liquid-infused surfaces. Furthermore, the chitosan conjugated LIS significantly reduced biofilm formation of methicillin-resistant Staphylococcus aureus (MRSA) by up to 50% and 75% when compared to untreated titanium and chitosan-coated titanium, respectively. The engineered coating can be easily modified with other biopolymers or capture molecules to be applied to other biomaterials where tissue integration and biofilm prevention are needed.

Effects of a ZnCuO-Nanocoated Ti-6Al-4V Surface on Bacterial and Host Cells.

This study aims to investigate the effects of a novel ZnCuO nanoparticle coating for dental implants—versus those of conventional titanium surfaces—on bacteria and host cells. A multispecies biofilm composed of Streptococcus sanguinis, Actinomyces naeslundii, Porphyromonas gingivalis, and Fusobacterium nucleatum was grown for 14 days on various titanium discs: machined, sandblasted, sandblasted and acid-etched (SLA), ZnCuO-coated, and hydroxyapatite discs. Bacterial species were quantified with qPCR, and their viability was examined via confocal microscopy. Osteoblast-like and macrophage-like cells grown on the various discs for 48 h were examined for proliferation using an XTT assay, and for activity using ALP and TNF-α assays. The CSLM revealed more dead bacteria in biofilms grown on titanium than on hydroxyapatite, and less on sandblasted than on machined and ZnCuO-coated surfaces, with the latter showing a significant decrease in all four biofilm species. The osteoblast-like cells showed increased proliferation on all of the titanium surfaces, with higher activity on the ZnCuO-coated and sandblasted discs. The macrophage-like cells showed higher proliferation on the hydroxyapatite and sandblasted discs, and lower activity on the SLA and ZnCuO-coated discs. The ZnCuO-coated titanium has anti-biofilm characteristics with desired effects on host cells, thus representing a promising candidate in the complex battle against peri-implantitis.

A strategy to design Ti-based in-situ bulk metallic glass composites containing controllable volume fraction and composition of the dendrite phase using conventional titanium alloy Ti–6Al–4V

Up to now, the composition design in the field of Ti-based in-situ dendrite reinforced bulk metallic glass composites (BMGCs) has been a great challenge. In this work, a simple but effective strategy is proposed to tailor the dendrite composition and volume fraction by using conventional Titanium alloy Ti–6Al–4V, and a series of in-situ dendrite reinforced BMGCs (Z1-Z4) are prepared based on it. The dendrite volume fraction can be adjusted by changing the proportion of the Titanium alloy Ti–6Al–4V, while the compositions of the dendrites are highly correlated with Ti–6Al–4V. In these alloys, with the increase of the mass percent of the added Titanium alloy Ti–6Al–4V, the volume fraction of the dendrite phase increases monotonically from Z1 to Z4 alloy. Z1 alloy behaves like a BMG with a high yield strength and limited plasticity due to its small dendrite size. Z2-Z4 alloys show excellent plasticity and significant work-hardening ability, because the dendrite size is appropriate and the dendrites undergo stress-induced martensite transformation during compression. From Z2 to Z4 alloy, with the increase of dendrite volume fraction from 56% to 78%, the yield strength does not decrease, which is due to the gradually enhanced stability of the dendrites. This composition design strategy is effective and universal, which can provide a new perspective for the composition design and development of TiZr-based in-situ dendrite reinforced BMGCs.

Finite element analyses of porous dental implant designs based on 3D printing concept to evaluate biomechanical behaviors of healthy and osteoporotic bones

Conventional dense titanium (Ti) implants cause stress shielding, aseptic loosening and implant failure. This study investigates the effects of porous dental implants (63% porous and 77% porous) with different neck angles (straight, 10° and 15°) on the healthy and osteoporotic bone under different loading conditions (axial load and buccolingual load). Simulation results showed that in cortical bone, the von Mises stresses are greater in the case of 77% porous Ti implant A (straight) as compared to implant B and C (10°, 15° angled neck). Overall, in the case of the osteoporotic bone, the strains are higher than the healthy bone.

Efficient and clean epoxidation of methyl oleate to epoxidized methyl oleate catalyzed by external surface of TS-1 supported molybdenum catalysts

Methyl oleate (MO) macromolecules are unable to access the microporous channel of conventional titanium silicalite-1 (TS-1) zeolite, which leads to the low catalytic activity of epoxidation of MO. Herein, the small-size TS-1 (TS-1-s) zeolite with a large surface area was synthesized successfully through steam-assisted crystallization, and then a novel blocked TS-1-s supported molybdenum (Mo/TS-1-bs) catalysts were prepared for efficient epoxidation of MO with clean H 2 O 2 to produce epoxidized methyl oleate (EMO). Various characterization results show the introduced Mo species are highly dispersed on the outer surface of TS-1-s without destroying the structure of the MFI type zeolite and the tetrahedral framework titanium (Ti 4+ ). Interestingly, a large number of Mo 6+ species exhibit certain epoxidation activity attributing to the generating of electrophilic molybdenum hydroperoxide (Mo–OOH) species via Mo species combined with H 2 O 2 , which could adsorb and react easily with MO molecules. Furthermore, the Mo species are also coordinated with Ti 4+ species through the O atom resulting in the facile attack of the Ti–O bonds by H 2 O 2 and easy to form an active intermediate. Therefore, compared with the conventional TS-1, the Mo/TS-1-bs shows higher catalytic activity in the epoxidation reaction. However, the acidity of Mo/TS-1-bs catalysts increases with increasing the Mo-loading owing to the formation of Lewis acid, which leads to the side reactions and the decrease of EMO selectivity. As a consequence, the efficient, non-corrosive and green catalytic system for epoxidation of MO was developed, and the activity improvement of Mo species and the influence of acid were also demonstrated. • The clean small-size TS-1 and Mo/TS-1-bs catalysts were prepared successfully for epoxidation of methyl oleate (MO). • Mo species can promote the MO epoxidation through generating of molybdenum hydroperoxide and coordination with Ti 4+ . • The acidity of Mo/TS-1-bs catalysts can decrease the selectivity of epoxidized methyl oleate.

Morphology Control of Monomer-Polymer Hybrid Electron Acceptor for Bulk-Heterojunction Solar Cell Based on P3HT and Ti-Alkoxide with Ladder Polymer.

We report the morphology control of a nano-phase-separated structure in the photoactive layer (power generation layer) of organic–inorganic hybrid thin-film solar cells to develop highly functional electronic devices for societal applications. Organic and inorganic–organic hybrid bulk heterojunction solar cells offer several advantages, including low manufacturing costs, light weight, mechanical flexibility, and a potential to be recycled because they can be fabricated by coating them on substrates, such as films. In this study, by incorporating the carrier manager ladder polymer BBL as the third component in a conventional two-component power generation layer consisting of P3HT—the conventional polythiophene derivative and titanium alkoxide—we demonstrate that the phase-separated structure of bulk heterojunction solar cells can be controlled. Accordingly, we developed a discontinuous phase-separated structure suitable for charge transport, obtaining an energy conversion efficiency higher than that of the conventional two-component power generation layer. Titanium alkoxide is an electron acceptor and absorbs light with a wavelength lower than 500 nm. It is highly sensitive to LED light sources, including those used in homes and offices. A conversion efficiency of 4.02% under a 1000 lx LED light source was achieved. Hence, high-performance organic–inorganic hybrid bulk heterojunction solar cells with this three-component system can be used in indoor photovoltaic systems.

Metastable dual-phase Ti–Nb–Sn–Zr and Ti–Nb–Sn–Fe alloys with high strength-to-modulus ratio

Conventional dual-phase titanium (Ti) alloy exhibits high strength and toughness, but the high elastic modulus makes it unsuitable for biomedical implants. In this study, two novel metastable dual-phase (α"+β) Ti–Nb–Sn–(Zr/Fe) systems have been developed using [Mo]eq theory. The dual-phase α"+β structure contributed to the alloys’ characteristics of high strength and low elastic modulus. The bending strengths of Ti–(16−22)Nb–8Sn–(5−8)Zr and Ti–(17−19)Nb–8Sn–(0.5–1.5)Fe alloys (1023–1190 MPa and 960–1308 MPa, respectively) were obviously higher than that of Ti–25 Nb–8Sn (962 MPa). Among them, both Ti–18Nb–8Sn–7Zr and Ti–19Nb–8Sn–0.5Fe with dual phase had lower elastic moduli (50.4 and 50.5 GPa, respectively) than Ti–25Nb–8Sn (52 GPa), which can avoid the stress shielding effect after implantation. Ti–18Nb–8Sn–7Zr and Ti–19Nb–8Sn–0.5Fe alloys exhibited greater bending strength-to-modulus ratios (20.3 and 19.0, respectively) than those of c.p. Ti (7.1) and Ti–25Nb–8Sn (18.5). Both dual-phase Ti–18Nb–8Sn–7Zr and Ti–19Nb–8Sn–0.5Fe with low elastic moduli and high strength-to-modulus ratios are promising candidates for bio-implant applications.

Inanimate surface contamination of SARS-CoV-2 during midfacial fracture repair in asymptomatic COVID-19 patients

PurposesTo evaluate inanimate surface contamination of SARS-CoV-2 during midfacial fracture repair (MFR) and to identify relevant aggregating factors. MethodsUsing a prospective non-randomised comparative study design, we enrolled a cohort of asymptomatic COVID-19 patients undergoing MFR. The predictor variables were osteofixation system (conventional titanium plates [CTiP] vs. ultrasound-assisted resorbable plates [USaRP]). The main outcomes were the presence of SARS-CoV-2 on four different surfaces. Other study variables were categorised into demographic, anatomical, and operative. Descriptive, bi- and multivariate statistics were computed. ResultsThe sample consisted of 11 patients (27.3% females, 63.6% right side, 72.7% displaced fractures) with a mean age of 52.7 ± 20.1 years (range, 19–85). Viral spread was, on average, 1.9 ± 0.4 m. from the operative field, including most oral and orbital retractors’ tips (81.8% and 72.7%) and no virus was found at 3 m from the operative field, but no significant difference was found between 2 osteofixation types. On binary adjustments, significantly broader contamination was linked to centrolateral MFR (P = 0.034; 95% confidence interval [CI], 0.05 to 1.02), and displaced MFR > 45 min (P = 0.022; 95% CI, 0.1 to 1.03). ConclusionsUSaRP, albeit presumably heavily aerosol-producing, cause similar SARS-CoV-2 distribution to CTiP. Non-surgical operating room (OR) staff should stay ≥ 3 m from the operative field, if the patient is SARS-CoV-2-positive. Enoral and orbital instruments are a potential virus source, especially during displaced MFR > 45 min and/or centrolateral MFR, emphasising an importance of appropriate patient screening and OR organisation.

Comparison of the shear bond strength of composite resins with zirconia and titanium using different resin cements.

The shear bond strength of conventional zirconia (3Y-TZP), translucent zirconia (5Y-PSZ), and titanium alloy (Ti6Al4V) thermocycled using different phosphate monomer resin cements were investigated. In this study, 120 specimens of 3Y-TZP, 5Y-PSZ, and Ti6Al4V were cemented to nanocomposite resin cylinders using PANAVIA™ V5 and Rely X™ U200. The bond area and resin cement thickness were controlled as per ISO 29022:2013 and 4049:2009. Each resin cement group was used with/without the Clearfil ceramic primer plus. The shear bond strength of the 12 groups was statistically analyzed using two and one-way ANOVA to determine the properties of the different materials and resin cements (α = 0.05). The mode of failure was observed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The titanium alloy groups showed better shear bond strength than the zirconia groups (p < 0.05). PANAVIA™ V5 without primer showed significantly lower shear bond strength than other cements in zirconia and titanium alloy specimens (p < 0.05). Titanium alloy with Rely X™ U200 with a Clearfil ceramic primer plus showed the highest shear bond strength (6.37 ± 1.60 MPa). SEM images showed mixed failures in zirconia groups and cohesive failures in titanium alloy groups. The titanium alloy showed better shear bond strength than zirconia when the Clearfil ceramic primer plus was used. The primer solution containing MDP and resin cement with phosphoric methacrylate ester showed similar shear bond strength with 3Y-TZP and 5Y-PSZ. The resin cement without phosphate monomers demonstrated the least shear bond strength.

Titanium Mesh Exposure in Guided Bone Regeneration Procedures: A Systematic Review and Meta-analysis.

To investigate whether titanium mesh exposure is influenced by the type of titanium mesh, the type of bone graft material, or the associated employment of absorbable membranes. Electronic literature searches were conducted using four databases: PubMed, EMBASE, Web of Science, and Cochrane. Articles reporting titanium mesh exposure rates were included, and exposure rates in different subgroups were compared to determine whether a factor significantly influenced titanium mesh exposure. The review protocol was registered in the PROSPERO registry (CRD42020210187). Twenty and 12 articles were included in the qualitative and quantitative synthesis, respectively. The weighted exposure rates of employing conventional titanium mesh or 3D-customized titanium mesh were 19.9% and 15.2% (P = .34). When employing autogenous bone combined with anorganic bovine bone material as bone graft material, the weighted exposure rate was 21.7%, whereas when using other bone graft material, the exposure rate was 23.5% (P = .74). The weighted exposure rate of using titanium mesh associated with absorbable membranes is 23.9%, while the weighted exposure rate of using titanium mesh without absorbable membranes is 20.2% (P = .36). Meta-regression showed that when analyzing one factor, the other two confounding factors did not influence the result (P = .28). It seemed that the type of titanium mesh, the type of bone graft material, or the combined employment of absorbable membranes did not statistically significantly influence the titanium mesh exposure rate in guided bone regeneration.

Development of Titanium Matrix Composites for Aerospace applications

Titanium Matrix Composites are very interesting for aerospace applications. These materials typically present higher Young Modulus and resistance than conventional titanium alloys. The ceramic reinforcement can be continuous or discontinuous (fibers or particles). Main advantages of discontinuously reinforced TMCs are the isotropic mechanical properties and the lower production costs. This work presents the development of discontinuously reinforced TMCs with TiC as reinforced particles. The reinforcement was obtained by Combustion Synthesis and the final consolidation by Spark Plasma Sintering. Main advantage of this PM process is the short processing time. Regarding the thermos-mechanical characterization, the material presents higher stiffness and resistance with higher thermal conductivity than conventional Ti-6Al-4V. This work also presents the scale-up of the SPS process to obtain aerospace demonstrators. Machining and joining issues are also considered.