ENGINEERING PHYSICS –II BY

M.VISHNUMENON

BIOMATERIAL• The Materials Which are used

for structural applications in the fields of medicine are know as biomaterials

• These materials are used to make devices to replace damaged or diseased body parts in human and animal bodies

• A variety of devices and materials are used in the treatment of disease or injury. Commonplace examples include suture needles, plates, teeth fillings, etc

Classification Of Biomaterial

Based on the application in the medical

field biomaterial are classified into :• Metals and alloys biomaterials• Ceramics biomaterials • Polymer biomaterials• Composite biomaterials

Metal And alloys

• Metals and alloys are used as biomaterials due to their excellent electrical and thermal conductivity and mechanical properties

• Types of Metal and alloys are cobalt based alloys, titanium, stainless steel , protosal from cast alloy, conducting metals such as platinum

• The advantage of metal High strength, Fatigue resistance, Relatively good wear resistance, Easy fabrication ,Easy to sterilize ,Shape memory (NiTi-Nitinol)

• Disadvantages are High elastic modulus, Corrosion ,Metal ion sensitivity and toxicity Low wetting

Applications of Metal and alloy

• Metals and alloys biomaterials are used in implant and orthopedic application

• Stainless steel Predominant implant alloy

• Protosal from cast alloy of Co ,Cr ,Mo used for implant hip Endo prosthesis and advance version of this protosal are widely used in hip joints

• ASTMF-136 used in dental application for making screws wires artificial teeth

• Ni –Ti shape memory alloy used in dental arch wire, micro surgical instrument, blood clot filtes.etc

Ceramics

• Ceramics are used as biomaterials due to their high mechanical strength and biocompatibility

• Types of Bio-ceramic materials are tri calcium phosphate, Metals oxides such as Al2O3 and SiO2 ,Apatite ceramics, Porous ceramics, Carbon and Alumina

• Advantage - High compression strength, Wear & Corrosion resistance ,Can be highly polished

• Disadvantage -High E modulus (stress shielding) Brittle -Low fracture toughness Difficult to fabricate

Applications of Ceramics• Al2O3 and SiO2 - used to make

femoral head • Tri calcium Phosphate - bone

repairs• Alumina used in

orthopedic ,Porous alumina used in teeth roots

• Apatite ceramics - bio active ceramics-used as synthetic bone

• Carbon good biocompatibility, wide application in heart valves

• Percutaneous carbon – stimulation of cochlea and visual cortex for artificial hearing and aid the blind respectively

BIOPOLYMERS

• Biopolymers are macromolecules (protein, nuclei ,acids and polysaccharides) formed in nature during the growth cycles of all organism

• Easy to make complicated items Tailor able physical & mechanical properties Surface modification Biodegradable

• Leachable compounds Absorb water & proteins etc. Surface contamination Wear & breakdown Biodegradation (hydrolytically, enigmatically) Difficult to sterilize

Application of Biopolymers

• Synthetic polymeric materials have been widely used in medical disposable supplies, prosthetic materials, dental materials, implants, dressings, extracorporeal devices, encapsulates, polymeric drug delivery systems, tissue engineered products

• The main advantages of the polymeric biomaterials compared to metal or ceramic materials are ease of manufacturability to produce various shapes (latex, film, sheet, fibers, etc.)

COMPOSITE BIOMATERIALS • The term “composite” is

usually reserved for those materials in which the distinct phases are separated on a scale larger than the

• biomaterial applications are: (1) dental filling composites

(2) reinforced methyl methacrylate bone cement and ultra-high-molecular-weight polyethylene, and

(3) orthopedic implants with porous surfaces. atomic

Biomaterial in ophthalmology and Dental

OPHTHALMOLOGY• Used to improve vision, eye

implants, to restore cornea, lens when they are damaged

• Contact lens, eye shield , vitreous replacement, correction of corneal curvature

DENTAL• Polymers ,composites

ceramic materials and metals alloys are four main groups of materials used for dental applications

• Ex: stainless steal, Co-Cr-Mo alloy PMMA ,proplast and deacon

END

Interesting facts

• As a science, biomaterials is about fifty years old