For plastic fillings often a composite material will be used – this is a plastic reinforced by ceramic filler material. Optically the almost match a ceramic inlay.
Composite fillings may be applied both to the front and the posterior area of the tooth. The ranges of application required by the universities of fillings on the front, dental neck, and small occlusal surfaces unfortunately in the posterior tooth area are often exceeded since too large fillings reaching into the dental gap areas because of the lower costs involved. In the gap areas the composite fillings have their weaknesses, since the composite material adheres at best to the tooth enamel and this at the occlusal surface is the thickest and at the dental neck the thinnest. Additionally, by the very moist environment of the dental neck areas no sufficiently strong bond between the plastic and the tooth substance is possible that leads to a soon and complete dissolution of the already weak bond. For this reason, unfortunately very often unnoticed a secondary tooth decay arises whereby the occlusal surface still looks sound. But in the not visible gap unperceivedly decay will be built up. By and by this will lead to dental nerve inflammations causing strong pain and will require a root canal treatment. For striking reasons, in the occlusal molar area it will be more advisable to go for a ceramic inlay. This form of treatment requires a higher investment but pays off because of its long durability. Ceramics inlays fixed in the 1990ies are still sound and since then the technology evolved, thus the durability may have been enhanced.
Additionally, composite fillings are not occlusally stable and will be rubbed off due to the high masticatory forces. Within the mouth the plastic fillings directly will be introduced to the tooth and finally shaped. The advantage of a composite filling is the fast making within one session and the are cost-effective. However, with composite there will be a chance that the material will shrink – therefore, in particular, it is important to apply the filling in several layers. Under local anaesthesia the tooth will be drilled to a special hole form and then finally filled with an aesthetic, tooth-coloured filling material. In the opposite to ceramics inlays they have a shorter stability but are also characterised by a lifelike colour.