A rigorous field analysis of the problem of two identical perfectly conducting parallel wedges with dented edges loaded with a dielectric cylinder, and excited by an electric or magnetic line current in the upper sector, is given in this paper. The dielectric medium is assumed to be linear, homogeneous, isotropic and free from losses, whereas the mediums of the upper and lower sectors are free space. A field equivalence theorem is used to derive, for each excitation, a system of coupled integral equations for the equivalent magnetic currents on the dielectric interfaces, which is later solved using Galerkin's method. The fields and powers transmitted into the lower sector, hence the transmission coefficients, for both polarisations are subsequently determined in terms of the equivalent magnetic currents on the lower dielectric interface. The analysis is then specialised to the problem of a slit loaded with a dielectric cylinder, as well as to the case of plane wave excitation. Sample numerical results for the dielectric-loaded double dented wedge and slit problems in the case of plane wave excitation are also given.