Clinical long-term studies have shown that composites demonstrate far greater durability after 12 years than amalgam. In general terms this is always dependent on the individual risk of caries. Secondary caries lesions tend to occur less frequently under amalgam restorations, but they often fail due to fracturing of the tooth substance (Cracked Tooth Syndrome). This risk is reduced considerably with composite restorations due to their chemical bonding to the tooth.
However, certain rules need to be followed when processing and optimal conditions need to be present. In this connection, Dr. Loomans underlines that a dry working area is absolutely essential for the durability of a composite filling. When selecting a bonding system one should avoid single bottle systems if possible as the components can separate easily and etching performance is considerably less than when applying 38 % phosphoric acid.
Furthermore, attention should be paid to marginal adaptation of the composite in the approximal area as this prevents the forming of gaps and thus premature occurrence of secondary carious lesions. Matrices and matrix bands as well as wedges are essential for creating point-shaped contact points to the adjacent tooth and provide periodontal-prophylactically adequate and anatomically correct contouring of the composite.