ABSTRACT One of the most common characteristics of recovered archaeological ceramic objects are gaps or missing parts, due to the conditions they have been exposed to, or to the history of materials. This is the reason why, of the different stages involved in the restoration process of archaeological ceramics, formal reintegration fulfils a double function: to provide both stability to the artefact and a correct legibility. Throughout history, just as at present, various materials have been used in the production of clays for the reconstruction of missing parts in archaeological ceramics. Nowadays, research on new materials has brought countless products to the field of restoration, so traditional ones are progressively being replaced. The choice of these products is most of the times based on their easier workability, or on the comfort offered by an already prepared material. The thesis is divided into three different parts which, at the same time, complement each other: An initial section where a historical review of the conservation treatments for archaeological ceramics is carried out. A second section, where there is an in-depth study of the criteria, processes and materials used in restoration works throughout history, particularly with regard to gap treatments. Finally, there is a third section in which the research methodology is explained, as well as the results obtained after the different ageing tests performed on the various fillers analysed. ?? ?? ?? ??