This study examines stress analysis of the mandible when submitted to mastication simulated forces over a distal extension removable partial denture. Two situations were analyzed upon loading: small pins had been placed over the bone crest and under the denture; low amplitude loads were applied over tooth 34-37. Holographic interferometry techniques were used to assess mandible's deformation. Results indicate that a correct adaptation of the denture base is critical to reduce stresses in the mandible. High stress levels in the second molar region suggest its non-inclusion in these prosthetic rehabilitations.