A composite (tooth colored) filling is used to repair a tooth that is affected by decay, cracks, fractures, etc. The decayed or affected portion of the tooth will be removed and then filled with a composite filling.
Because composite fillings are tooth colored, they can be closely matched to the color of existing teeth, and are more aesthetically suited for use in front teeth or the more visible areas of the teeth.
In addition to matching the tooth colors, composite forms a chemical bond to dentin and a mechanical bond to enamel, adding strength to the remaining tooth structure, rather than just occupying space.
The longevity of the composite restorations will be determined mostly by how much tooth is left, how strong the bond is that forms, and how forceful the chewing forces are on the tooth. The only stronger restoration would be a crown, and that would be appropriate where there is too little natural tooth left to bond composite.
Reasons for composite fillings:
How are the advantages and disadvantages of composite fillings?
Composite fillings are usually placed in one appointment. They can be made to look exactly like real teeth. Sometimes the composites in direct bonding can even greatly improve on the color, shapes, and position of the natural teeth (see section on Direct Bonding).
If there is very little natural tooth remaining to restore it is usually a better idea to place a crown that will surround the tooth with a protective shell, providing better mechanical strength rather than depending upon bonding strength alone.