ARTIFICIAL TEETHPRESENTED BY: DR.

TABISH ZIA KHATTAK

INDRODUCTIONCONSTITUTE ONE OF THE MAIN COMPONENTS OF DENTURE.

• Commonly used materials• Acrylic• Porcelain

IDEAL REQUIREMENTS• Esthetics

• Should ideally match the Natural teeth in shape , color & translucency.

• Good attachment to denture base• Low density

• Light weight dentures.

• Strong and Tough• To resist fracture.

• Resist aberration• during Chewing & Cleaning.

• Allow easy Chair-side adjustments• to adjust occlusion.

• Resist Staining

COMPOSITIONACRYLIC TEETH PORCELAIN TEETHPOWDER 1) Clay (Kaolin)

• Polymer, PMMA 2) Silica• Initiator, Benzoyl peroxide 3) Binder (Feldspar)

• Pigments 4) GlassesLIQUID• Monomer, MMA

• Cross-linking agent, Ethylene-glycol-dimethacraylate.

• Inhibitor, Hydroquinone.

• Activator, N N -dimethyl-p-toluidine′

FABRICATIONACRYLIC TEETH PORCELAIN TEETH• Reusable metal moulds using Fabrication involves

a) Dough Moulding Technique. a) Compaction

b) Injection Molding Technique. b) Firing

Standard shapes & sizes produced by

using molds 30% larger than required

to allow shrinkage during firing.

• Highly cross-linked resins Small holes or metal pins are

used to resist crazing incorporated in the base of Porcelain

teeth during their production

Mechanical attachment.

ADVANTAGES OF ACRYLIC TEETH

1)Easy to adjust and trim2)Chemical bonding to denture base, as they are made of the same

material3)Acrylic teeth are more compatible with the denture base than

porcelain teeth.4)No clicking sound

ADVANTAGES OF ACRYLIC TEETH

5) Easy to fabricate

6) Less trauma to denture-bearing area. This is particularly crucial for people with implants supporting the fake tooth. If they have lost

bone or gum tissues around the implant, acrylic teeth are more forgiving when you grind your teeth, and will hold their position

longer than porcelain teeth.

7) Dentures made with acrylic teeth are lighter

DISADVANTAGES OF ACRYLIC TEETH

1) Acrylic teeth are susceptible to abrasion, e.g. if the

patient has a habit of teeth-grinding (bruxism) or eats

rough diets, the teeth will wear down with time,

causing changes in the length of the teeth.

2) Easily stained, as they contain microscopic pits that can

hold bacteria

3) In rebasing, difficult to remove acrylic teeth from the

denture base

ADVANTAGES OF PORCELAIN TEETH

1) Although both acrylic and porcelain teeth can be made

to give a natural appearance, the slightly greater

translucency and depth of color achieved with porcelain,

gives this material a slight advantage.

2) Harder than acrylic more durable.

3) Resist wear- this preserves the normal jaw movements

and alignment for a longer period.

4) Resist staining

ADVANTAGES OF PORCELAIN TEETH

5) Occasionally, due to resorption of the edentulous

ridges, the denture becomes loose and does not fit the

mouth at all. Instead of remaking a new denture, the

base of the denture can be replaced (called “rebasing”)

while retaining the artificial teeth so that the Occlusion

will not be altered. Because porcelain teeth do not bond

chemically to the base, they are easily removed from the

base for this purpose.

DISADVANTAGES OF PORCELAIN TEETH1) Noisy: clicking sounds are made when porcelain

teeth comes into occlusion with another porcelain

tooth

2) Brittle – more likely to fracture than acrylic teeth

3) Do not bond chemically to denture base –Small

holes or metal pins are incorporated in the base of

porcelain teeth during their production to enable

mechanical bonding to the denture base.

DISADVANTAGES OF PORCELAIN TEETH4) Not as compatible as acrylic teeth with the base of the denture – There is a serious mismatch in coefficient of thermal and modulus of elasticity between porcelain and acrylic resin. This may lead to crazing and cracking of the denture base in the region around the base of the porcelain teeth.5) Its density value is about twice that of acrylic teeth;

dentures constructed with porcelain teeth are much heavier. 6) Difficult to fabricate.

DISADVANTAGES OF PORCELAIN TEETH

7) Difficult to trim, due to the hardness of this material.

8) Porcelain teeth exert more force to the underlying

supporting soft tissues, causing more trauma to these tissues.

This is a function of the greater modulus of elasticity of

porcelain. This trauma is capable of accelerating the rate by

which the underlying bone resorbs.

DIFFERENCE BETWEEN ACRYLIC & PORCELAIN TEETHPROPERTIES ACRYLIC

TEETHPORCELAIN TEETH

1). Aesthetics A more realistic Customized

appearance can be achieved. Good but not long-

lasting. Easily

stained/discolored.

A more realistic Customized

appearance can be achieved. Better & long-lasting. Greater translucency. Depth of color.

2). Clicking sound Absent Present

3). Attachment Mechanism Chemical adhesion to DB.

More Compatible with DB material.

Mechanical retention to DB.

Less Compatible with DB.

DIFFERENCE BETWEEN ACRYLIC & PORCELAIN TEETHPROPERTIES

ACRYLIC TEETH

PORCELAIN TEETH

7). Hardness/Wear

Less hard , suffer abrasion. Wear out with time

Much harder, no abrasion. Much durable. Teeth easily removed for re-

basing if required.

8). Adjustability Easily adjusted by grinding.

Easily polished following adjustment.

Difficult to adjust On grinding glaze is lost. Difficult to polish

9). Cost Cheap Costly

IMPORTANT TIPS

CLEANING OF DENTURES