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INTRODUCTION TO BIOMATERIALS SCIENCE & MATERIALS STRUCTURE DASMAWATI MOHAMAD, PhD BIOMATERIALS SCIENCE WEEK
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INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Apr 13, 2018

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Page 1: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

INTRODUCTION TO BIOMATERIALS SCIENCE

& MATERIALS STRUCTURE

DASMAWATI MOHAMAD, PhD

BIOMATERIALS SCIENCE WEEK

Page 2: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

OBJECTIVES

• Students will have an ample knowledge on biomaterials science and technology to meet the challenges of modern dentistry.

• Students are capable of selecting, manipulating, and evaluating dental materials based on a scientific understanding of their structure and properties.

• Students are able to understand the reasons for clinical failure of dental materials and can critically evaluate materials reported by manufacturers and research publications.

• To cultivate an interest in biomaterials research for a development of new or improved performance of products used in dentistry.

Page 3: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Abbreviation: L – Lecture, P – Practical, SGD - Small Group Discussion, A, B, C, D, E, F – Students GroupsLectures: 12hrs, Practicals: 10 hrs, SGD: 2hrs, Self study: 4hrs, Total hrs per week: 28 hrs

Date 8.30 – 9.30am 9.30 – 10.30am 10.30 –11.30am 11.30-12.30 noon 2.00-3.00pm 3.00 – 4.00pm 4.00-5.00pm

Sunday21.10.07

L1: Introduction to Biomaterial Science & Material structure (Dr Dasmawati)

L2: Biological properties (Pn Suria)

L3: Physical properties & Chemical properties (Dr Dasmawati)

Self Study L4: Genotoxicity(Dr T.P. Kannan)

SGD 1:Physical properties –A,B,C,D,E,F – Dr Dasmawati, Dr Zuryati, Dr Wan Zaripah, Dr Adam, Dr Norliza Mastura, Dr Tin

Monday22.10.07

L5: Principles of Adhesion (Dr Zuryati)

L6: Mechanical properties(Dr Dasmawati)

P1: Material Testing Lab (Mechanical properties) –– D,E,F -Dr Dasmawati, En MarzukiP2: Tissue bank – A,B,C –Dr Suzinaand Mr Goh,

L7: Tissue Engineering & Stem Cell (Dr Suzina)

P1: Material Testing Lab (Mechanical properties) –A,B,C– Dr Dasmawati, En MarzukiP2: Tissue bank – D,E,F –Dr Suzina and Mr Goh

Tuesday23.10.07

L8: CAD-CAM Application of Biomaterials (Dr Zainul)

L9: Application of Bone graft & Material-Tissue Interface(Dr Noor Hayati Razak)

P3: Cytotoxicity – All students (MDL) –Pn Siti Fadilah, Cik Eda and En Marzuki

L10: Ceramics(Dr Norhayati Luddin)

P4: Dental Tech.Lab (Porcelain Coping) – A,B,C- Tn Hj AbdullahP5: Dental lab ((Maxillofacial Prosthesis Materials)) – D,E,F –Tn Hj Abdullah

Wednesday24.10.07

L11: Alloy (Dr Wan Zaripah)

L12: Polymers & Composites (Dr Dasmawati)

P4: Dental Tech.Lab (Porcelain Coping) – D,E,F- Tn Hj Abdullah

P5: Dental lab (Maxillofacial Prosthesis Materials) – A,B,C – Tn Hj Abdullah

5th Student Scientific Conference Rehersal

Thursday25.10.07 5th Student Scientific Conference

Page 4: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

INTRODUCTION TO BIOMATERIALS SCIENCE

Part I

Page 5: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Lectures outlinePart I: Introduction of Biomaterials Science:• Characteristics of biomaterials• What subjects are important to biomaterials science ?• Biomaterials in dentistry• History of biomaterials in dentistryPart II: Materials Properties:• Atomic arrangement• Bonding• Composition• Defect

Page 6: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Characteristics of Biomaterials• Definition of Biomaterials: a non-living material designed to interact

with biological systems• Three main areas of use of biomaterials;

– Dental restoratives materials, e.g. metallic & composite filling materials, and casting alloys and ceramics for fixed and removable intraoralprosthesis

– Structural implants, e.g. oral and maxillofacial implants and joint prostheses

– Cardiovascular implants, e.g. catheters, prosthetic heart valves and blood vessels

Page 7: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Characteristics of Biomaterials• Multidisciplinary

– Bring together researches from diverse academic background

– e.g.; bioengineer, chemist, chemical engineer, electrical engineer, mechanical engineer, materials scientist, biologist, microbiologist, physician, veterinarian, ethicist, nurse, lawyer, regulatory specialist and venture capitalist

• Many diverse materials– Biomaterials can be polymers, ceramic, metals,

composite or many different synthetic and modified natural materials

• Development of new materials

Page 8: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

What subjects are important to Biomaterials Science ?

• Biocompatibility• Possible adverse effects of the

biomaterials• Mechanical and performance requirement• Ethics

– A wide range of ethical considerations impact biomaterials science

Page 9: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Biocompatibility• Definition: ability of a material to obtain an appropriate biological

response in a given application in the body• Depends on the condition of the host, the properties of the material• Biological response in the dental environment

- biological interfaces with dental materials; dentin-resin interfaceand the implant-bone interface- for dentin-resin interface if the resin material does not penetrate the collagenous network a gap will form resulting in leakage, thus alter the biocompatibility of the restoration. May allow bacteria to reach the pulp and cause infection and also may encourage the breakdown of the material.

• How to measure biocompatibility?- for new biomaterial involved three phases of testing; primary (in vitro), secondary (in vivo), and usage - eg; in vitro;cytotoxicity, genotoxicity tests

Page 10: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Possible adverse effects of the biomaterials

• Toxicity, inflammation, allergy, mutagenicity-Toxicity-dose related potential of a material to cause

cell or tissue death-Inflammation- involves the activation of the host’s

immune system to fight off some threat. It may result from toxicity or allergy

-Allergy- occurs when the body specifically recognizes a material as foreign and reacts disproportionately to the amount of the material present

-Mutagenicity- result when the components of a material alter the base-pair sequences of the DNA in cells.

How safe are dental restorative materials?• Munksgaard (1992) concluded, occupational risks in dentistry

are low and the patient risk for side effects of dental treatment is extremely low.

Page 11: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Mechanical and performance requirement

• In dentistry, need to know how well the materials used are able to withstand the forces generated from the action of mastication and occlusion

• Studied done to determine the biting force. Guinness Book of Records (1994)-the highest biting force as 4337 N sustained for 2 sec. Average maximum biting force is approx. 756 N.

• Hence, in designing of a dental prosthesis, strength is the important factor. The ability of the prosthesis to resist induced stress without fracture or permanent deformation. (will be discussed later)

Page 12: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Biomaterials In Dentistry• Historically, variety of materials have been used as tooth

crown and root replacements including, animal teeth, bone, human teeth, ivory, seashells, ceramics and metals.

• An ideal restorative material would be– Biocompatible– Bond permanently to tooth structure or bone– Match the natural appearance of tooth enamel, dentin and other

tissues– Exhibit properties similar to those of tooth enamel, dentin and

other tissue– Be capable of initiating tissue repair or regeneration of missing

or damage tissues

Page 13: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Biomaterials In DentistryCan be classified into three categories:1. Preventive materials

Eg. pit and fissure sealants, sealing agents that prevent leakage, liners, bases, GIC

2. Restorative materialsconsist of all synthetic components that can be used to repair or replace tooth structure. Eg. primers, bonding agents, cements, resin composites, amalgam, compomers, ceramics, denture polymers

3. Auxiliary Materialssubstances that are used in the process of fabricating dental prostheses and appliances but that do not become part of these devices. Eg. impression materials, casting investments, gypsum cast, dental waxes, bleaching tray.

Page 14: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

History of Biomaterials In Dentistry

First gold filling

Etruscan goldbridge work

Ivory dentures

Proposal of the use of porcelain by Fauchard

The use of silver and mercury to make a paste for filing teeth is suggested by Taveou of Paris

1st dental journal is published, American Journal of Dental Science

Amalgam war

Vulcanite is invented by Charles Goodyear

1st cement, zinc phosphate to set in the mouth is introduced

Silicate cements are developed

Detailed study of the properties of amalgams is published by G.V. Black

Practical method of casting gold inlays

Acrylic resin for fillings & dentures is introduced

Acid etch technique is discovers by Buonocore

Composites begin to replace silicate cements

GICs are invented by A. Wilson

Light activated composites appear on the market

Horn introduced resin bonded ceramic veneer

Development of DBA

Introduction of resin-modified glass ionomercements

1st

compomersappear on the market

600BC

AD1480

1500s1728

1826 1839 18501840s 19761879 18951880s 19701955

1950s19071985

198819831978 1994

Page 15: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

MATERIALS STRUCTUREPart II

Atomic arrangementBonding

CompositionDefect

Page 16: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

DENTAL MATERIALS

METALS CERAMICS POLYMERS COMPOSITES

Implants, Restoratives, Wires

Restoratives,Crowns

Dentures Restoratives, Adhesive

Page 17: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Atomic Arrangement• Crystalline structures

– Arrangement of its neighbouring atom is identical– Space lattice- any arrangement of atoms in space in

which every atom is situated similarly to every other atom.

– Dental amalgam, cast alloys, wrought metals, gold foil, pure ceramics (alumina, zirconia) are crystalline

– Dental porcelains consist of noncrystalline glass matrix and cystalline

– Many metals used in dentistry is in cubic arrangement, one of 14 possible lattice types. Body centered cubic (BCC), face centered cubic (FCC) Lattice types depend on length of three unit cell edges and the angles between the edges.

– Packing factor; BCC = 0.68, FCC = 0.74

Page 18: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Atomic ArrangementMetal Atomic diameter

(angstroms)Crystal structure

Gold 2.882 Face-centered cubic

Platinum 2.775 Face-centered cubic

Palladium 2.750 Face-centered cubic

Silver 2.888 Face-centered cubic

Copper 2.556 Face-centered cubic

Tin 3.016 Body centeredtetragonal

Zinc 2.665 Close-packed hexagonal

Silicon 2.351 Diamond cubic

Page 19: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Atomic Arrangement

• Non-crystalline structures– Amorphous form- no symmetry of the atoms– Do not have definite melting temperature, however

they gradually soften as the temperature increase and there is an abrupt increase in the thermal expansion coefficient indicating increase of molecular mobility at certain temperature known as glass transition temperature, Tg.

– Below Tg, the glassy structure– Eg. Dental resins have a glassy structures

Page 20: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Bonding

Bonding is the cohesive forces that hold atoms together and classified as primary and secondary.

Primary Bonding: • Ionic bonds• Covalent bonds• Metallic bonds

Page 21: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Primary Bonding: Ionic Bonds• Ionic Bonds are forces that hold ionic compounds together • Following is the example of sodium chloride (Na+Cl-)

Mosby-Year Book. Inc

Page 22: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Primary Bonding: Covalent bonds• H2 is an example of covalent bonding. The single valence electron in each

H is shared with that of the other combining atom, the valence shells become stable.

Mosby-Year Book. Inc

Page 23: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

• Octet Rule (Lewis) - an atom other than hydrogen tends to form bonds until it is surrounded by eight valence electrons

• The Bond order describes the bond1 = single, 2 = double, 3 = triple- A single bond is formed when 1 pair of electrons is shared - A double bond is formed when 2 pairs of electrons are shared- A triple bond is formed when 3 pairs of electrons are shared

• Covalent bonding occurs in many organic compounds, including dental resins

• Example in quartz and diamond

Page 24: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Primary Bonding: Metallic Bonds• results from the increased spatial extension of valence-electron wave functions when an aggregate of metal atoms is brought close together.• e.g. a metallic crystal such as pure gold. Easily donate electrons from their valence shell. A cloud of electrons will form surrounds the atoms.

Page 25: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Secondary Bonding-do not share electrons-resulting from electrical imbalance known as an electric dipole.

• Van der Waals forces– Short-range force of physical attraction that promotes

adhesion between molecules of liquids or molecular crystals

• Hydrogen bonding– Dipole-dipole interaction. Eg. A water molecule– Associated with the positive charge of H caused by

polarization. When a water molecule intermingles with other water molecule, the H (+ve) portion of one molecule will attracted to the O (-ve) portion of its neighbouring molecule, formed hydrogen bridges.

Page 26: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Bonding: Bond distance– Liming factor that prevents

the atoms or molecules from approaching each other too close

– If the atoms approach too close, they are repelled from each other by their electron charges. On the other hand, forces of attraction tend to draw the atoms together.

– The position at which forces of attraction and repulsion become equal in magnitude is the equilibrium positions of the atoms, interatomic distance a.

Page 27: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Bonding: Bond energy– Amount of energy that

has to be supplied to separate the two atoms

– Generally, covalent bonds the strongest, followed by the ionic bonds, then metallic bonds

Page 28: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Bonding

• In general,– Ceramics- based on the ionic bond– Metals- metallic bond– Molecular solids (polymers)- based on the

covalent and secondary bonds

Page 29: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Composition

• Elements, components, phases• Equilibrium and non-equilibrium phase

diagrams

Page 30: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

Defects

• Point, line, area, volume defects• Dislocation motions• Grain boundaries

Page 31: INTRODUCTION TO BIOMATERIALS SCIENCE … DAS 8102006/INTRODUCTION TO...Part I: Introduction of Biomaterials Science: • Characteristics of biomaterials • What subjects are important

THANK YOU &SELAMAT HARI RAYA!