In this paper, a new model for bone resorption using mixture theory with chemical reactions is proposed. Three constituents (matrix, fluid and cells) are considered. Conservation equations (mass, momentum and energy) are provided for each constituent and for the whole mixture. Entropy inequality for the mixture is also given. The rate of mass transfer between phases, caused by chemical reactions, is assumed to be a function of extent of chemical reactions, deformation gradient, temperature and temperature gradient. Using constitutive equations in the 2nd law of thermodynamics, a new criteria for the resorption equilibrium state is concluded.