Fillings are specially selected dental materials used to fill cavities or defects in teeth as the result of either tooth decay or damage by excessive force. Different types of materials including metals, composite resins, porcelain and zirconia have been used. As the strength, durability, biocompatibility and aesthetic properties are vastly different, the choice of filling material depends on clinical and patient factors including cost. The decayed portion is first removed and the remaining tooth structure then prepared by shaping the cavity and refining the margins before inserting the filling.
Types of Dental Fillings
What do the terms inlay and onlay mean?
An inlay is a tooth filling which is made in the dental laboratory to fit the mould of a tooth cavity. It is then returned to the clinic for the dentist to cement. As the filling fits within the boundaries of the tooth it is termed an inlay. An onlay is a type of inlay where the underlying tooth structure is more extensively broken down and a much larger part of the tooth needs to be covered or overlaid by the replacement filling material, hence the term “onlay”.
How are Computer designed and manufactured fillings made?
The tooth is scanned and a filling custom designed using digital technology. Pre-fabricated blocks of filling materials such as porcelain, zirconia or plastics are trimmed to exact specification in a laboratory using precision tooling in a “milling” machine. The process is highly automated. The end-product is then heat treated to harden it and produce a smooth or glazed surface. The dentist then attached the fillings using a special biocompatible cement. Porcelain and plastic fillings can be made within hours while Zirconia fillings will need an extra day to process.
How do you fill or repair a fractured tooth?
Teeth may fracture following a traumatic injury or as a result of strong bite forces over time. Depending on the extent of damage, the tooth can either be repaired or removed. The tooth is assessed and the smaller portion of the cracked tooth is removed. If the remaining tooth structure is sound, the tooth can be filled. The tooth is first roughened and a liquid (an acid) used to create micro-pores on the tooth surface. A thin layer of a special bonding agent is applied before a resin filling is attached and hardened using a special blue light source. Larger fractures may require a crown.