Dental caries or tooth decay is a multifactorial infectious disease affecting the tooth hard structure (enamel, dentine as well as cementum). It causes most of dental complications including teeth cavities, tooth loss, dental abscesses, and pulp exposure.
There are myriad classifications of tooth caries, but the best classification is G.V.Black classification, which classifies dental carries according to its location on tooth surface.
Generally, tooth caries can occur at any site of tooth surface, for each site, there is a specific kind of a filling material suitable for it.
Mainly, dental fillings are classified into two categories according to the way of application in oral cavity:
Direct Filling
The filling material is inserted directly in the oral cavity by the dentist. All procedures are finished in one appointment.
Example:
-Amalgam (silver)
-Composite (white)
Indirect Filling
These are made by the laboratory especially for each patient (custom made). All the dentist has to do is to cement them in their places. Mostly, procedures take 2 or more visits to dental clinic.
Examples:
-Crowns (or caps)
- Inlays
The best known direct filling material is amalgam, while cast gold alloy is the best known indirect filling material. Nowadays, dental ceramics are becoming more popular, because of their better durability and esthetics.
Furthermore, dental fillings are classified according to their appearance in oral cavity into:
A. Metallic
1. Amalgam Fillings
Dental amalgam fillings are the most commonly used type of filling in dentistry. Because of amalgam silver color, amalgam fillings are mainly used in the filling of upper and lower posterior teeth. Amalgam alloy is a mixture of myriad types of metals, including mercury, silver, copper and tin.
Advantages
1.Cheap
2.Longevity
3.Easy manipulation
Disadvantages
1.Bad esthetic
2.Leaching of mercury over time
2. Cast Gold Fillings
After cleaning the caries from your tooth, the dentist will take an impression of your teeth and send it to dental lab, where a model is made from your teeth mold. The dental technician will custom made a cast gold filling to your tooth, polish it, and send it back to your dentist to cement it in your oral cavity.
Advantages
1.High strength
2.Durability
Disadvantages
1.Very expensive
2.Long procedures
3.Bad esthetics
B. Tooth- colored
1-Composite fillings (plastic or white filling)
Usually, the dentist cleans the tooth from caries, irrigate thoroughly, then place a bonding or adhesive material to the prepared tooth structure. Composite material is placed increment by increment in the prepared hole in your tooth; each increment is hardened by a special light beam. Finally, the dentist must shape to have same contour and appearance of natural neighboring teeth.
Advantages
1.Very good esthetics
2.Less expensive than gold fillings
3.Easy manipulation and short procedures
Disadvantages
1.Easily fractured
2.Less durability
3.High risk of recurrent caries
4.More expensive than amalgam fillings
2-Glass ionomer fillings
This type of filling is used in the filling of areas which are not subjected to high occlusal forces in oral cavity; they are used mainly to restore deciduous teeth.
Advantages
1.Very good esthetics
2.High fluoride content, which decreases recurrent caries
3.Easier in manipulation than composite
4.Less cost than composite and gold fillings
Disadvantages
1.Weak, easily dissolved in oral cavity
2.Higher costs than amalgam
3.Porcelain Materials
Nowadays, the most commonly used type of dental ceramic by dentist is porcelain. Porcelain is an indirect filling material, which is fabricated in the dental lab and cemented by dentist in oral cavity.
Advantages
1.Excellent esthetics
2.High durability
3.High strength
Disadvantages
1.Most expensive filling material
2.Long procedures (indirect filling)
3.Contra-indicated in filling of molars, can’t withstand teeth which bite down hard