Titanium Ions Release from an Innovative Titanium-Magnesium Composite: an in Vitro Study

Svrha: U ovom radu istraživala su se korozijska svojstva inovativnog titanij-magnezijeva (Ti-Mg) kompozita proizvedenog metodom metalurgije praha (P/M). Materijal i metode: Ispitivane su dvije grupe eksperimentalnog materijala – s 1 masenim udjelom (mass% Ti-1Mg) i 2 masena udjela (mass% Ti-2Mg) magnezija u titanijskoj osnovi te su uspoređene s komercijalno čistim titanijem (CP Ti). Test uranjanja i kemijska analiza četiriju otopina: umjetne sline, umjetne sline pH 4, umjetne sline s dodatkom fluora i Hankove otopine, provedeni su nakon 42 dana uranjanja metodom masene spektrometrije induktivno spregnutom plazmom (ICP – MS) kako bi se ustanovila količina otpuštenih iona titanija (Ti). Za određivanje svojstava površine korištene su analize SEM i EDS. Rezultati: Razlika u rezultatima između različitih ispitivanih otopina procjenjivana je ANOVA-om i Newman-Keulsovim testom na razini značajnosti od p < 0,05. Utjecaj prediktorskih varijabli utvrđivan je multiplom regresijskom analizom. Rezultati ovog istraživanja pokazuju nisku stopu korozije titanija u ispitivanoj skupini Ti-Mg. Uočeno je do 46 puta, odnosno 23 puta manje otapanje iona titanija iz Ti-1Mg i Ti-2Mg u usporedbi s kontrolnom skupinom. Između ispitivanih otopina, umjetna slina s dodatkom fluora pokazala je najveći korozijski učinak među svim ispitivanim uzorcima. SEM-analiza pokazala je sačuvanu dvofaznu strukturu površine, a EDS-analiza upozorila je na moguća bioaktivna svojstva površine. Zaključak: Ti-Mg kompozit proizveden metodom P/M-a sugerira se kao materijal boljih korozijskih svojstava u usporedbi s čistim titanijem (CP Ti).The innovative titanium-magnesium composite (Ti-Mg) was produced by powder metallurgy (P/M) method and is characterized in terms of corrosion behavior. Material and methods: Two groups of experimental material, 1 mass% (Ti-1Mg) and 2 mass% (Ti-2Mg) of magnesium in titanium matrix, were tested and compared to commercially pure titanium (CP Ti). Immersion test and chemical analysis of four solutions: artificial saliva; artificial saliva pH 4; artificial saliva with fluoride and Hank balanced salt solution were performed after 42 days of immersion, using inductively coupled plasma mass spectrometry (ICP-MS) to detect the amount of released titanium ions (Ti). SEM and EDS analysis were used for surface characterization. Results: The difference between the results from different test solutions was assessed by ANOVA and Newman-Keuls test at p<0.05. The influence of predictor variables was found by multiple regression analysis. The results of the present study revealed a low corrosion rate of titanium from the experimental Ti-Mg group. Up to 46 and 23 times lower dissolution of Ti from Ti-1Mg and Ti-2Mg, respectively was observed compared to the control group. Among the tested solutions, artificial saliva with fluorides exhibited the highest corrosion effect on all specimens tested. SEM micrographs showed preserved dual phase surface structure and EDS analysis suggested a favorable surface bioactivity. Conclusion: In conclusion, Ti-Mg produced by P/M as a material with better corrosion properties when compared to CP Ti is suggested

Effects of Wire EDM on the Microstructure of P/M Titanium Samples

Komercijalno čisti titanij (CP Ti) se koristi u dentalnoj medicini zbog biokompatibilnosti, dobrih mehaničkih svojstava i otpornosti na koroziju. Konvencionalni proizvodni procesi izrade takvog titanija mogu utjecati na kvalitetu površine uzoraka i rezultirati slabim vezanjem CP Ti s dentalnom keramikom. Zato se uvode nove tehnologije proizvodnje titanija, primjerice metalurgija praha i oblikovanje na erozimatu s žicom (WEDM). Svrha ovog istraživanja jest odrediti utjecaj WEDM-a na površinu uzoraka P/M CP Ti proizvedenih za ispitivanje vezne čvrstoće prema normi ISO 9693. Materijali i metode: Osam uzoraka P/M CP Ti dimenzija prema normi ISO 9693 proizvedeno je korištenjem WEDM-a i podijeljeno u dvije grupe – u neobrađene i brušene. Površine obje grupe uzoraka analizirane su metodama SEM, EDS i XDR. Rezultati: Analize neobrađenih uzoraka metodama SEM i EDS pokazuju tanki sloj različitog sastava i frakture. Brušeni uzorci imaju homogenu strukturu bez fraktura. Analiza metodom XDR pokazuje visoku koncentraciju titanijevih oksida na površini neobrađenih uzoraka, a nakon brušenja dobivena je samo čista α-faza. Zaključak: WEDM je metoda prikladna za proizvodnju uzoraka prema normi ISO 9693, ako se uzorci naknadno bruse.Purpose: Commercially pure titanium (CP Ti) has been recognized in dentistry for its biocompatibility, good mechanical properties and corrosion resistance. Conventional manufacturing processes can affect surface quality and result in poor bonding of dental ceramics to CP Ti. This is why powder metallurgy (P/M) and wire electro-discharge machining (WEDM) are being introduced in the manufacturing process. The aim of this study was to evaluate the effect of WEDM on the surface composition and microstructure of P/M CP Ti samples produced for bond strength testing according to ISO 9693. Materials and methods: Eight samples of P/M CP Ti, dimensions according to ISO 9693, were made using WEDM and divided in two groups (untreated and grinded). Microanalyses of chemical composition and microstructure of both groups were made using SEM, EDS and XDR. Results: SEM and EDS analysis of untreated samples showed a thin layer on surfaces with fractures in it. Grinded samples showed homogenous structure with no layer and no fractures. XDR analysis showed high level of oxides on the surface of untreated samples, while after grinding only pure α-phase was found. Conclusion: WEDM is a suitable method of sample production for ISO 9693 if accompanied by grinding with silicon carbide papers P320-P4000

Delayed Intracranial Hemorrhage in Patients with Head Trauma and Antithrombotic Therapy

Background: Delayed intracranial hemorrhage can occur up to several weeks after head trauma and was reported more frequently in patients with antithrombotic therapy. Due to the risk of delayed intracranial hemorrhage, some hospitals follow extensive observation and cranial computed tomography (CT) protocols for patients with head trauma, while others discharge asymptomatic patients after negative CT. Methods: We retrospectively analyzed data on patients with head trauma and antithrombotic therapy without pathologies on their initial CT. During the observation period, we followed a protocol of routine repeat CT before discharge for patients using vitamin K antagonists, clopidogrel or direct oral anticoagulants. Results: 793 patients fulfilled the inclusion criteria. Acetylsalicylic acid (ASA) was the most common antithrombotic therapy (46.4%), followed by vitamin K antagonists (VKA) (32.2%) and Clopidogrel (10.8%). We observed 11 delayed hemorrhages (1.2%) in total. The group of 390 patients receiving routine repeat CT showed nine delayed hemorrhages (2.3%). VKA were used in 6 of these 11 patients. One patient needed an urgent decompressive craniectomy while the other patients were discharged after an extended observation period. The patient requiring surgical intervention due to delayed hemorrhage showed neurological deterioration during the observation period. Conclusions: Routine repeat CT scans without neurological deterioration are not necessary if patients are observed in a clinical setting. Patients using ASA as single antithrombotic therapy do not require in-hospital observation after a negative CT scan

Management of Traumatic Brain Injury in Patients with DOAC Therapy&ndash;Are the &ldquo;New&rdquo; Oral Anticoagulants Really Safer?

(1) Background: In recent years, &ldquo;new&rdquo; direct oral anticoagulants (DOAC) have gradually replaced other antithrombotic therapies. The international literature agrees on the increased mortality for traumatic brain injury (TBI) patients using vitamin K antagonists (VKA), but thus far, there are insufficient data on the influence of DOAC on the outcome of TBI. (2) Methods: We retrospectively analyzed data from all patients who presented with head trauma using antithrombotic therapy. Outcome parameters were the presence of pathologies on the initial CT, occurrence of delayed intracranial hemorrhage, surgical intervention, and death. (3) Results: In total, data of 1169 patients were reviewed. Of those, 1084 (92.7%) had a mild TBI, 67 (5.7%) moderate TBI, and 17 (1.5%) severe TBI. In total, 456 patients (39%) used DOAC and 713 patients (61%) used VKA, antiplatelet therapy, or prophylactic doses of low molecular weight heparin at the time of trauma. The groups showed no significant differences in age, injury mechanisms, or GCS at presentation. Overall, the initial cranial CT showed pathologies in 85 patients (7.3%). Twenty-five patients with head trauma and DOAC therapy had pathological findings on CT (5.5%), 11 patients with VKA (4.8%), and 48 patients with antiplatelet therapy (10.6%). There was a statistically significant difference in occurrence of CT pathologies between DOAC alone compared to acetylsalicylic acid (4.9 vs. 10.5%, p = 0.04). Delayed intracranial hemorrhage after an initially negative CT during in-hospital observation occurred in one patient (0.2%) in the DOAC group, two patients (0.9%) in the VKA group, and four patients (0.9%) in the antiplatelet group without statistical significance. Head trauma related surgery was performed in three patients (0.7%) in the DOAC group, two patients (0.9%) in the VKA group, and six patients (1.3%) in the antiplatelet group without statistical significance. Death due to head trauma occurred in four patients (0.9%) of the DOAC group compared to one patient (0.4%) of the VKA group and five patients (1.1%) of the antiplatelet group without statistical significance. (4) Conclusions: Our data suggest a comparable risk of pathological CT findings, delayed intracranial hemorrhage, surgical interventions, and death after blunt head trauma for patients with DOAC compared to VKA, but a lower risk for pathological CT findings compared to platelet inhibitors. As VKA are known to increase mortality, our data suggest that similar caution should be used when treating patients with head trauma and DOAC, but the overall numbers of serious or severe courses after simple falls remain low. We recommend routine CT for all head trauma patients with antithrombotic therapy but the role of in-hospital observation for patients with mild TBI remains a matter of debate