1) TOOTH RESTORATION

It is the first step in treating dental caries (Tooth decay); life span of any restoration depends mainly on:

• Age of the patient: Elderly patients have less caries incidence than young ages.

• Properties of the filling material.

• Patient care.

 

2) RESTORATION FAILURE

When restoration fails it should be replaced. The reason of failure may be failure of the restoration material or decay of the tooth structure around the restoration.

 

3) RESTORATION REPLACEMENT

It is a complicated process and sometimes more expensive than the initial restoration. They may have shorter life span and can have harmful effect on the pulp, occasionally leading to the need for root canal treatment involving further expenses.

 

4) RESTORATION MATERIALS

A- COMPOSITES       

                            

Definition

Composites are a mixture of filler particles, consisting of various types of translucent glass, embedded in a resin matrix that binds the filler particles together, and all are tooth colored.

 

Points with

• Composites are esthetic (tooth colored).

• Composites bond to tooth structure thus not requiring enlarged cavities in the tooth body.

• Composites can be used for both front and back teeth.

• Not containing mercury as amalgam restoration.

• Have strength in thin sections.

 

Points against

• Composites are more expensive than amalgam.

• Composites require high skill and precise work.

• Composites contract on curing process; this may lead to some sort of temporary pain on biting.

• Composites physical properties may influence its long-term performance.

 

Amalgam fillings

Composites replacing amalgams

B- AMALGAM (SILVER) FILLINGS

 

Definition

Amalgam is an alloy of mercury with silver and other metals as tin, zinc and copper to give a compound that does not adhere to tooth tissue and is not tooth colored.

 

Points with

• Amalgam is the least expensive among other restoration materials.

• Amalgam has a long-term performance.

• Amalgam condensability against the walls of the cavity together with its tarnish and corrosion properties helps in complete and continuous marginal seal.

• Amalgam has a good physical properties.

 

Points against

• Amalgam is a brittle material which has no strength in thin sections.

• Amalgam creeps under pressure so it loses its form.

• Amalgam does not adhere or bond to tooth tissues. Thus amalgam necessitates enlarging small carious defects to form a large and deep box shaped cavities.

• Amalgam has a metallic dark looking that turns black as it ages. (Not tooth colored).

• Although amalgam’s tarnish and corrosion aid in its marginal seal, it also may be considered as a disadvantage as it changes the physical properties of the material.

• Amalgam has two main defects that adversely affect a patient's health which are:

  • Release of mercury and other metals from the amalgam into the body. Mercury is a toxic metal, the most minute amount damages cells.

  • There is a galvanic action between the five metals composing the amalgam that is harmful for the body.

 

C- GLASS IONOMER CEMENTS

These are tooth colored materials that adhere chemically to tooth tissue and consists of a matrix and embedded filler particles, their water solubility limits their usage to be as a base under amalgam and composites or as a cement for gold and other casting fillings.

 

D- CAST GOLD AND OTHER ALLOYS

Cast gold or alloy restorations are called inlays and are made outside the mouth in an indirect technique.

The advantage of cast inlays is their strength in thin sections; they can be used to protect weak tooth structure.

The main disadvantages are the high cost; they need more visits; they need highly qualified laboratories and finally they have the disadvantage of being cemented.

 

E- PORCELAIN

These are inlays constructed from porcelain and can be cemented into a prepared cavity directly.

Porcelain inlays have the advantage of being tooth colored but have many disadvantages of being expensive, require highly qualified laboratory, being brittle, more than one visit is needed, and it should be cemented.