Biomaterials Science Chapter 1 Overview

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Questions and Answers

What primarily distinguishes solids from liquids and gases?

Their constituent atoms are held together by strong interatomic forces. (correct)

Their constituent atoms are loosely bound.

They are composed of negatively charged ions.

They have a crystalline structure.

Which of the following types of interatomic bonds is NOT a primary bond?

Ionic bonds

Covalent bonds

Metallic bonds

Hydrogen bonds (correct)

What property allows metals to conduct heat and electricity?

Loosely bound electrons that move freely (correct)

High tensile strength

Tightly bound ionic cores

Regular cubic crystalline structures

What structural arrangement do the positive ion cores in metals typically adopt?

Regular cubic or hexagonal crystalline structures Signup and view all the answers

Which of the following is NOT a classification of biomaterials?

Biocompatible Biomaterials Signup and view all the answers

What determines the mechanical properties of metals?

The arrangement of positive ion cores and their bonding Signup and view all the answers

Which characteristic of metals contributes to their ductility?

The ability of planes of atoms to slide past one another Signup and view all the answers

What type of biomaterials can be classified as biodegradable materials?

Bioresorbable Biomaterials Signup and view all the answers

What property of metals makes them suitable for orthopedic applications?

High tensile strength and good fatigue resistance Signup and view all the answers

Which of the following metals is known for its toxicity when accumulated in the body?

Aluminum Signup and view all the answers

Which characteristic is NOT essential for metals used in medical implants?

High electrical conductivity Signup and view all the answers

What is the primary reason for the concern about corrosion in metal implants?

It leads to the release of harmful metal ions into the body. Signup and view all the answers

Which type of stainless steel is primarily used in medical applications?

316L stainless steel Signup and view all the answers

What is one significant advantage of metallic implants over ceramics and polymers?

Higher tensile strengths and fatigue resistance Signup and view all the answers

Why are metals mostly used in alloyed forms rather than their elemental form in medical applications?

Alloys provide improved mechanical properties and corrosion resistance. Signup and view all the answers

What two metals are primarily used in alloys alongside stainless steel for medical applications?

Titanium and cobalt-chromium Signup and view all the answers

What is an important consideration when selecting metals for implants in a physiological environment?

Resistance to corrosion and potential toxicity Signup and view all the answers

What is the primary characteristic that metals must possess for areas subjected to cyclic loading?

Good fatigue properties Signup and view all the answers

Study Notes

Introduction to Solids

Solids are characterized by strong interatomic forces binding their atoms, differing from liquids and gases.
Properties of solids depend on the nature and strength of interatomic bonds: ionic, covalent, and metallic.

Classification of Biomaterials

Biomaterials are categorized into three types:
- Bioinert Biomaterials: Do not elicit a significant biological response.
- Bioactive Biomaterials: Interact positively with biological tissues.
- Bioresorbable Biomaterials: Biodegradable materials that are absorbed by the body.

Characteristics of Metals

Metals feature a structure of positively charged ion cores surrounded by a sea of loosely bound electrons, enabling conductivity.
They have close-packed crystalline structures, influencing mechanical properties: strength and ductility.
Ductility allows metals to deform under stress without fracturing.

Applications of Metals in Medicine

Metals are utilized in implants, such as electrodes in cardiac devices (e.g., platinum).
They replace or support damaged body parts, including joints, bones, and skull plates.
Fixation devices stabilize broken bones and assist in tissue healing.

Advantages of Metallic Implants

Metals possess high tensile strength and fatigue resistance, making them suitable for orthopedic applications.
They are less prone to brittle fracture, providing safety as they deform rather than suddenly fail.

Considerations for Metallic Implants

Reaction with the physiological environment (37 °C aqueous solution with gases, electrolytes, proteins) is crucial.
Corrosion resistance is vital to prevent harmful ion release and ensure mechanical integrity.
Toxicity of metals like aluminum can be a concern if accumulated excessively in the body.
Cost of materials influences the choice of metals for medical applications.

Essential Features of Metallic Implant Materials

Corrosion resistance is mandatory.
Mechanical properties must align with application requirements.
Good fatigue properties are necessary for areas under cyclic loading.
Compatibility in terms of corrosion resistance is essential.

Commonly Used Metallic Alloys

Metals are usually alloyed; for instance, brass is an alloy of zinc and copper.
Stainless steel (primarily 316L) is widely used in medical applications.
Other significant alloys include commercially pure titanium and cobalt-chromium alloys.

Major Alloy Systems for Implants

Stainless steels: Predominantly 316L stainless steel (ASTM F-138).
Cobalt-chromium-molybdenum alloys: Known as CoCrMo (ASTM F-75; ASTM F799; ASTM F1537).
Titanium and its alloys: Utilized according to ASTM standards (e.g., ASTM F76, ASTM F136).

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Description

Explore the foundational concepts of solids as discussed in Chapter 1.2.2 and Chapter 1.3.3 of Biomaterials Science. This quiz delves into the properties of metallic biomaterials and their applications in medicine, addressing current challenges and opportunities. Test your understanding of key ideas and their implications in the medical field.