Clinically it can be presented with all mentioned clinical manifestations, starting from a non cavitated lesion and extending further in enamel or dentin.

 The reasons for formation of secondary caries are:

• Marginal gap formation between the restoration and the tooth surface
• Broken filling
• Loss of a part of the filling
• Initial caries development due to plaque accumulation around margins of the filling

 DIAGNOSIS

·        Can be performed with the same methods as for other forms of caries but in this case the visual examination of dental surfaces should be supported with additional diagnostic tools (bite wing). 

·        The 100% seal of the restored surface cannot be guaranteed for ever and as soon as the dentinal microbiota will obtain contact with oral environment, the destructive process in dentin towards the pulp will continue. 

·        The marginal gap around the restorations cannot be detected with the naked eye at the initial stage but the products of microbial metabolism (acids) on the surface can penetrate the minor microporosites that appear in the restored tooth surface.