Thanks to the unidimensional model of Ostwald ripening proposed here, the most general systems, in particular with high volume fraction can be studied and new aspects can be considered: influence of the spacial arrangement of the grains, first stage of ripening, influence of a non-constant mass diffusion coefficient. Ostwald ripening, or coarsening of second phase particles is one of the major causes of changes in the particle size distribution (PSD) with time for a given population of grains. It is particularly important for processes such as ageing of precipitates or liquid phase sintering. The first models (1) and (2,3) (LSW model) were based on several restrictive assumptions, in particular very small volume traction of grains and very dilute matrix or liquid phase. They predicted an asymptotic behaviour characterized by a cubic relationship of the mean particle size R versus time, when mass diffusion is the rate-determining step...