Cytocompatibility of Titanium Alloys Study

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Questions and Answers

What was the main objective of the study conducted on pure metals and titanium alloys?

The main objective was to evaluate the biocompatibility of nine types of pure metal ingots and 36 experimental titanium alloys.

Which pure metal displayed the highest cytotoxicity according to the study's findings?

Copper (Cu) exhibited the highest cytotoxicity.

What methods were used to compare cell viabilities in this study?

The WST-1 test and the agar overlay test were utilized.

What was the mean cell viability percentage for pure aluminum (Al)?

The mean cell viability for pure aluminum was 25.3%. Signup and view all the answers

Which two pure metals demonstrated good biocompatibility based on cell viability results?

Molybdenum (Mo) and Niobium (Nb) showed good biocompatibility. Signup and view all the answers

What was a notable finding regarding the titanium-based alloy groups?

All Ti-based alloy groups had mean cell viabilities higher than 80%, except for Ti-20Nb and Ti-10V. Signup and view all the answers

List the elements involved in the titanium alloys tested for biocompatibility.

The elements tested included 5, 10, 15, and 20 wt% of various alloying elements. Signup and view all the answers

What statistical significance level was noted in the study for comparing cell viabilities?

A statistical significance level of p < 0.05 was noted. Signup and view all the answers

What advantage does Ti–20% Ag and Ti–5% Cu alloys have over pure Ti in dental applications?

They exhibit better grindability, which is desirable for dental CAD/CAM alloys. Signup and view all the answers

How do the hardness and tensile strength of Ti–Au, Ti–Ag, and Ti–Cu alloys compare to those of pure Ti?

They are higher than those of pure Ti. Signup and view all the answers

What unique property does the Ti–Cr alloy exhibit compared to CP-Ti?

It has greater flexure strength. Signup and view all the answers

What factor contributes to the elastic recovery capability of Ti–20Cr alloy?

It is associated with the high flexure strength measured in the alloy. Signup and view all the answers

How does the elastic modulus of CP-Ti and Ti alloys compare to that of 316L stainless steel and Cr–Co alloys?

The elastic modulus of CP-Ti and Ti alloys is lower. Signup and view all the answers

Why is it important to conduct cytotoxicity assays for new Ti alloys?

To study the effect of each component on cell behavior. Signup and view all the answers

What are in vitro cytotoxicity tests known for in terms of speed and reliability?

They are relatively fast and provide highly reliable data. Signup and view all the answers

What does the mass release of an element from an alloy depend on, according to the content?

It is not expected to be proportional to its atomic percentage in the alloy. Signup and view all the answers

What properties of recently developed b-Ti alloys range from 55 to 85 GPa, and how do they compare to 316L stainless steel?

The recently developed b-Ti alloys exhibit lower elastic modulus compared to 316L stainless steel, which has a higher modulus. Signup and view all the answers

Name three alloying elements that have been investigated as b stabilizers for Ti alloys.

Manganese (Mn), molybdenum (Mo), and niobium (Nb) are three alloying elements investigated as b stabilizers. Signup and view all the answers

What is the purpose of biocompatibility tests for dental alloys, including Ti alloys?

The purpose is to evaluate the cytotoxicity of candidate Ti-alloys and ensure their safety for use in dental implants. Signup and view all the answers

What adverse effect can occur from the release of metallic ions from titanium alloys during corrosion?

The release of metallic ions can be toxic or irritating to surrounding tissues. Signup and view all the answers

How does the Ti–6Al–4V alloy impact bone marrow stromal cells, based on current reports?

Ions from the Ti–6Al–4V alloy can inhibit the normal differentiation of bone marrow stromal cells to mature osteoblasts in vitro. Signup and view all the answers

What method is used to fabricate binary Ti–A alloys in the study, and what atmosphere is maintained during this process?

Binary Ti–A alloys are fabricated using vacuum arc melting under a high purity argon atmosphere. Signup and view all the answers

Why is it necessary to evaluate the biocompatibility of metallic materials during the development of Ti alloys?

Evaluating biocompatibility is necessary to ensure that biologically relevant molecules do not adversely react when released from the biomaterial. Signup and view all the answers

What procedures are involved in homogenizing prepared Ti alloy ingots?

The prepared ingots are melted seven times and treated for 4 hours at specific temperatures. Signup and view all the answers

What is the criterion for scoring cell lysis in the study?

Cell lysis was scored from 0 for no lysis to 3 for over 40% lysis. Signup and view all the answers

How was cytotoxicity evaluated in this study?

Cytotoxicity was evaluated using the agar overlay test and the WST-1 test. Signup and view all the answers

What was the effect of pure Cr in relation to cell lysis?

Pure Cr caused a cell response of 1/3, indicating some lysis despite a visible decolorization zone. Signup and view all the answers

What does a cell viability score indicate in this context?

A cell viability score reflects the percentage of cells that remained intact after exposure to the tested materials. Signup and view all the answers

What implications can the release of metal ions from implants have?

The release of metal ions can affect biocompatibility and cause complications in implant recipients. Signup and view all the answers

What processes can be used to examine the cytotoxicity of a biomaterial?

Cytotoxicity can be examined using a monolith form or a particulate form of the biomaterial. Signup and view all the answers

What is the cooling rate mentioned for the furnace process?

The cooling rate is approximately 10 °C/min. Signup and view all the answers

List two specifications for CP-Ti (Grade 2) as mentioned in the content.

The specifications for CP-Ti (Grade 2) are a rod shape of 10 mm dia. and adherence to ASTM B265. Signup and view all the answers

What is the purity percentage of the titanium sponge listed in the materials used?

The purity of the titanium sponge is 99.9%. Signup and view all the answers

What are the granule size specifications for manganese used in the study?

The manganese granules range from 0.8 mm to 10 mm. Signup and view all the answers

How were the prepared alloy buttons processed after being cut into disks?

The disks were polished using a sequence of abrasives and then ultrasonically cleaned. Signup and view all the answers

What identifies the manufacturer of zirconium foil used in the study?

The zirconium foil is identified as manufactured by Alfa Aesar, Ward Hill, USA. Signup and view all the answers

What is the significance of air cooling to room temperature in material processing?

Air cooling allows for a controlled decrease in temperature, minimizing thermal stress in the material. Signup and view all the answers

What specific test is used to assess the cytotoxicity of metallic implants?

The agar overlay test is used to assess the cytotoxicity of metallic implants. Signup and view all the answers

What cellular changes were observed in osteoblast-like cells when exposed to Cu or Ag?

Osteoblast-like cells displayed signs of apoptosis, including membrane blebbing and the formation of apoptotic bodies. Signup and view all the answers

Explain why biocompatibility testing of metal ingots is necessary.

Biocompatibility testing of metal ingots is necessary to evaluate the behavior of cells in contact with these materials and ensure their safety for human use. Signup and view all the answers

What were the observed effects on cells that contacted pure Mn, V, Ag, and Cu during the agar overlay test?

Cells that contacted these metals changed to a globular shape and exhibited blebbing, indicating apoptosis. Signup and view all the answers

How does exposure duration affect the signs of necrosis in cells exposed to metallic materials?

With longer metal exposure, signs of necrosis became more prevalent among the cells. Signup and view all the answers

In the context of the study, what role do alloying elements play in the cytotoxicity of metallic materials?

The mechanical, physico-chemical, and corrosion properties of the metals are significantly affected by the compositional variations of the alloys. Signup and view all the answers

What signs indicated that necrosis was rare in the cell samples studied?

Necrosis manifestations were hardly observed in the samples exposed to negative controls and CP-Ti. Signup and view all the answers

What conclusion can be drawn from the cell morphological study regarding metallic implants?

The study emphasizes the importance of cytotoxicity testing for metallic implants as they can be moderately cytotoxic to cells. Signup and view all the answers

Study Notes

Cytocompatibility of Pure Metals and Experimental Binary Titanium Alloys

The study evaluated the biocompatibility of pure metals (Ag, Al, Cr, Cu, Mn, Mo, Nb, V, Zr) and 36 experimental titanium alloys (containing 5, 10, 15, and 20 wt% alloying elements). The control was commercially pure titanium (CP-Ti).
Pure metals were ranked by cytotoxicity (most to least): Cu > Al > Ag > V > Mn > Cr > Zr > Nb > Mo > CP-Ti.
Low cell viabilities (<40%) were observed for Cu, Al, Ag, V, and Mn, which suggested high cytotoxicity compared to the control.
Zr and Cr displayed moderate cytotoxicity (74% and 60% mean cell viability, respectively).
Mo and Nb showed good biocompatibility, with cell viabilities close to CP-Ti levels (93.3% and 93%, respectively).
The majority of titanium alloys exhibited greater than 80% cell viability, with Ti-10Nb having the highest at 124.8%, even exceeding CP-Ti's viability.
The agar overlay test results correlated with the WST-1 test results, ranking pure metals by cytotoxicity type (e.g., Ag, Cr, Cu, Mn, and V being moderately cytotoxic).
The study concluded that Ti-10Nb showed high biocompatibility, indicating potential applicability for dental implants.

Materials and Methods

Samples of binary Ti-A alloys (where A is Ag, Al, Cr, Cu, Mn, Mo, Nb, V, and Zr; alloying elements at 5, 10, 15, or 20wt%) were created using vacuum arc melting and were treated (melted 7 times) to homogenize them.
Cell viability was measured using WST-1 and agar overlay tests on L-929 mouse fibroblast cells.
Agar overlay assays with neutral red were performed to evaluate cell viability by observing decolorized zones and cell lysis surrounding implanted samples.
Statistical analysis was conducted using SPSS software (version 19.0).

Results

Cell viability experiments on the various pure metal and titanium alloys were performed and compared to the CP-Ti control.
Mo and Nb showed a high level of biocompatibility.
Ag, Al, Cr, Cu, Mn, and V exhibited measurable cytotoxicity.
The Ti-based alloy samples generally exhibited cell viability higher than the control group, with a notable exception of Ti-20Nb, and Ti-10V.
Ti-10Nb, in particular, showed superior biocompatibility compared to the other samples assessed in the study.
The findings suggested differences in the cytotoxic potential of various pure metals and their corresponding Ti alloys.

Discussion

Metal ion release from implants can negatively affect biocompatibility.
Cytotoxicity assessments, using both metal ingots and solutions, are necessary for proper material testing.
The study highlighted the significance of alloy composition in influencing cytotoxicity.
The results emphasize that the properties of Ti alloys are relevant to their suitability for use in vivo.

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Description

This quiz explores the cytocompatibility of pure metals and experimental binary titanium alloys. Participants will learn about the rankings of metals based on cytotoxicity and analyze biocompatibility results, especially focusing on commercially pure titanium and various alloying elements. Test your knowledge of material biocompatibility in biomedical applications.