Bioactive Glasses and Glass-Ceramics: Properties and Applications in Biomaterials

Question 1

Which of the following is the defining characteristic of bioactive glasses?

Accepted Answer

Ability to integrate with living tissue

Answer

Exceptional mechanical strength

Answer

High electrical conductivity

Answer

Optical transparency

Question 2

Which specific ion is crucial for the bioactive properties of bioactive glasses?

Accepted Answer

Calcium

Answer

Sodium

Answer

Potassium

Answer

Magnesium

Question 3

What is the fundamental difference between a glass and a glass-ceramic?

Accepted Answer

Glasses are amorphous while glass-ceramics have a crystalline structure

Answer

Glass-ceramics are stronger than glasses

Answer

Glasses have a higher melting point than glass-ceramics

Answer

None of the above accurately describes the distinction

Question 4

What is the primary advantage of using bioactive glasses in the field of tissue engineering?

Accepted Answer

They promote cell adhesion and proliferation

Answer

They prevent infection

Answer

They provide mechanical support

Answer

They stimulate angiogenesis

Question 5

Which type of glass-ceramic is commonly used in dental restorations?

Accepted Answer

Leucite-based

Answer

Diopside-based

Answer

Mica-based

Answer

Zirconia-based

Question 6

What role does silica play in the composition of bioactive glasses?

Accepted Answer

Network former

Answer

Network modifier

Answer

Charge compensator

Answer

Surface active agent

Question 7

Glass-ceramics are typically stronger and tougher than traditional glasses due to the presence of:

Accepted Answer

Crystalline phases

Answer

Residual stresses

Answer

High porosity

Answer

Amorphous regions

Question 8

How does the composition of a bioactive glass directly impact its bioactivity and biocompatibility?

Accepted Answer

The ratio of silicon (Si) to calcium (Ca) influences the rate of hydroxyapatite formation, affecting bioactivity.

Accepted Answer

Adding sodium (Na+) ions enhances bioactivity by increasing the release of ions into the surrounding environment.

Accepted Answer

Including boron oxide (B2O3) improves biocompatibility by reducing the formation of a cytotoxic silica-rich layer on the glass surface.

Answer

Incorporating magnesium oxide (MgO) increases the mechanical strength of the glass but does not affect its bioactivity.

Question 9

Explain the role of Bioglass® in bone regeneration. Discuss its composition, properties, and clinical applications, providing specific examples.

Accepted Answer

Bioglass® is a bioactive glass composed of silicon dioxide, sodium oxide, calcium oxide, and phosphorus pentoxide, exhibiting excellent biocompatibility and osteoconductivity.

Answer

Bioglass® is a glass-ceramic with high mechanical strength but limited bioactivity, restricting its use in bone regeneration.

Answer

Bioglass® is primarily used as a coating on metal implants to enhance their biocompatibility, with limited standalone applications in bone regeneration.

Answer

Bioglass® has not demonstrated clinical significance and has not been approved for medical use.

Question 10

Which of the following advantages is unique to bioactive glasses and glass-ceramics in bone regeneration?

Accepted Answer

Ability to bond with bone tissue (osteoconductivity)

Answer

Increased biostability

Answer

Enhanced soft tissue integration

Answer

High strength and toughness

Question 11

Which type of bioactive glass, with a composition of 45% SiO2, 24.5% Na2O, 24.5% CaO, and 6% P2O5, exhibits a surface layer of hydroxyapatite that promotes bone growth?

Accepted Answer

45S5 Bioglass

Answer

Borate glass

Answer

Silica glass

Answer

Aluminosilicate glass

Question 12

Which technique is widely used to assess the ability of bioactive glasses to support cell growth and differentiation?

Accepted Answer

In vitro cell culture

Answer

Atomic force microscopy

Answer

X-ray diffraction

Answer

Mechanical testing

Question 13

What is the primary reason for using bioactive glass-ceramics in dentistry, particularly in restorative procedures?

Accepted Answer

Strong and durable bonding to dentin, the hard tissue of the tooth

Answer

Biocompatibility

Answer

Low thermal conductivity

Answer

High strength

Question 14

Which method is typically employed to transform glass into glass-ceramics, resulting in a material with both crystalline and amorphous phases?

Accepted Answer

Controlled cooling and heat treatment

Answer

Sintering alone

Answer

Annealing

Answer

Tempering

Question 15

What is the fundamental distinction between bioactive glasses and glass-ceramics?

Accepted Answer

Presence or absence of a crystalline structure

Answer

Bioactivity

Answer

Composition

Answer

Applications

Question 16

What is a potential drawback of using bioactive glasses and glass-ceramics in applications where high mechanical strength is crucial?

Accepted Answer

Lower mechanical strength compared to traditional materials like metals

Answer

Limited biocompatibility

Answer

High brittleness

Answer

Poor adhesion to tissues

Question 17

Which of the following accurately describes a key characteristic of bioactive glasses?

Accepted Answer

Bioactive glasses have the ability to bond to living tissue.

Answer

High electrical conductivity is not typically a key characteristic of bioactive glasses.

Answer

While biodegradability is a desirable property for some biomaterials, it is not a defining feature of bioactive glasses.

Question 18

What is the primary biological mechanism by which bioactive glasses stimulate bone growth?

Accepted Answer

Bioactive glasses release ions that interact with bone cells, triggering biological responses and promoting bone formation.

Answer

Bioactive glasses do not typically form a strong mechanical bond with bone tissue.

Answer

Bioactive glasses do not directly initiate a cascade of biochemical reactions leading to bone growth.

Answer

Bioactive glasses do not activate specific immune cells as their primary mechanism for stimulating bone growth.

Question 19

Which of the following materials is commonly used as a precursor for the production of glass-ceramics?

Accepted Answer

Glass powder is a common starting material for the production of glass-ceramics.

Answer

Ceramic powder is not typically used as a precursor for glass-ceramics.

Answer

Polymer resins are not commonly used as precursors for glass-ceramics.

Answer

Metal oxides can be used in the production of glass-ceramics, but they are not the primary precursor material.

Question 20

What is a primary advantage of using glass-ceramics over traditional glasses in biomedical applications?

Accepted Answer

Glass-ceramics offer improved mechanical strength and toughness compared to traditional glasses, making them more suitable for load-bearing applications.

Answer

Thermal conductivity is not significantly different between glass-ceramics and traditional glasses.

Answer

Increased porosity is not a general advantage of glass-ceramics over traditional glasses.

Answer

Biocompatibility is not a primary advantage of glass-ceramics over traditional glasses.

Question 21

Which of the following factors can influence the bioactivity of a bioactive glass?

Accepted Answer

Both the composition and surface characteristics of a bioactive glass can affect its bioactivity.

Answer

Processing temperature can influence properties of bioactive glasses, but it is not the primary factor affecting bioactivity.

Answer

Storage environment typically does not have a significant impact on the bioactivity of bioactive glasses.

Question 22

What is the primary application of bioactive glasses and glass-ceramics in the field of orthopedics?

Accepted Answer

Bioactive glasses and glass-ceramics are primarily used in orthopedics for bone repair and regeneration due to their osteoconductive and osteoinductive properties.

Answer

Bioactive glasses and glass-ceramics are not commonly used as artificial joints.

Answer

Tissue engineering scaffolds often employ bioactive glasses and glass-ceramics, but it is not their primary application in orthopedics.

Answer

Dental implants typically do not utilize bioactive glasses or glass-ceramics as the primary material.

Question 23

Which of the following is a potential limitation associated with the use of bioactive glasses in biomedical applications?

Accepted Answer

Bioactive glasses may elicit an inflammatory response and foreign body reaction in some individuals.

Answer

Bioactive glasses are generally low-cost materials.

Answer

Bioactive glasses exhibit high biocompatibility in most cases.

Answer

Bioactive glasses are relatively easy to manufacture.

Question 24

What is a key distinction between bioactive glass and bioactive glass-ceramic?

Accepted Answer

Bioactive glass-ceramics have a crystalline structure, while bioactive glasses are amorphous.

Answer

Bioactive glass-ceramics are not necessarily stronger than bioactive glasses.

Answer

Bioactive glass-ceramics typically exhibit similar biocompatibility to bioactive glasses.

Question 25

Which of the following techniques is commonly used to characterize the surface properties of bioactive glasses?

Accepted Answer

Scanning electron microscopy (SEM) is a widely used technique for analyzing the surface topography and morphology of bioactive glasses.

Answer

Atomic force microscopy (AFM) can be used for surface characterization, but it is less common than SEM for bioactive glasses.

Answer

Transmission electron microscopy (TEM) is not commonly used for surface characterization of bioactive glasses.

Answer

X-ray diffraction (XRD) is primarily used to determine the crystalline structure of materials, not surface properties.