11.3 dental implants and crowns

What are the three options to replace missing teeth

Dentures bridges and implants

What are the three main implant types

Subperiosteal transosteal and endosteal

Which implant type rests on bone surface

Subperiosteal

Which implant penetrates through bone

Transosteal

Which implant is most common

Endosteal

What are the three parts of an endosteal implant

Implant abutment and crown

Who discovered osseointegration

Per Ingvar Brånemark

What material did Brånemark study

Commercially pure titanium

Why is titanium suitable for implants

It forms a bioactive oxide layer

What oxide supports bone growth

TiO2

What crystal structure is titanium at room temperature

HCP alpha phase

What happens above 883 degrees Celsius

Titanium transforms to beta phase

What is beta phase structure

BCC

Is beta phase stronger or more brittle

Stronger but more brittle

Why are titanium alloys used

To improve strength and fatigue resistance

What elements stabilise alpha phase

Aluminium

What elements stabilise beta phase

Vanadium

What is simulated body fluid

Artificial solution mimicking blood plasma

What does SBF indicate

Bioactivity of materials

What is plasma spraying

A coating technique using molten particles

Why coat implants

To increase bioactivity and bone bonding

What implant surface gives best bone apposition

Rough isotropic surfaces

What is TPS coating

Titanium plasma sprayed coating

What bone types must be assessed before implantation

Type I to Type IV

What is Type I bone

Dense compact bone

What is Type IV bone

Very thin compact bone

What is osseointegration

Direct bone bonding to implant

What is the survival rate of implants after 15 years

91 to 96 percent

Why do most implant failures occur early

Failure of bone integration

What materials are crowns made from

Metal ceramic or metal ceramic composite

Why is gold used in crowns

High strength and corrosion resistance

What is the drawback of porcelain crowns

High fracture risk

Why use metal ceramic crowns

Strength from metal aesthetics from ceramic

What must ceramic do on metal

Wet the surface

Why is thermal expansion important

Ceramic must be in compression

What happens if metal contracts more than ceramic

Improved fracture resistance

What causes crown failure

Poor bonding or oxide layer failure

Who should not receive implants

Heavy smokers alcohol abuse gum disease immunocompromised patients

Why must gum disease be treated first

It causes bone loss

What is the key advantage of implants

Preserve bone and restore load transfer