Purpose: The aim of this study was to investigate the effect of viscosity modifiers on the mechanical properties of silicone elastomers Methods: One hundred twenty dumbbell-shaped and trouser-shaped specimens were produced using combinations of cosmosil M511 part A,part B and colorants(1 drop/5gm).Trouser-shaped specimens will be used to evaluate the tear strength of the maxillofacial material.While dumbbell-shaped specimens were utilized to evaluate the tensile strength and the elongation percentage.