Objective To study the distribution of stress of simulating teeth with wedge shaped defects in the cervical region. Methods The models of anisotropic enamel of the mandibular first premolar and the opposite maxillary first premolar crown were created. A deffect was introduced into the model of mandibular premolar in the buccal cervical region along the enamelo-dentinal junction（DEJ）. The stress distribution in the cervical region of the mandibular premolar was investigated considering lateral condition simulating working micromotions. In this case, the stroke was applied to the maxillary first mandibular in a stepping procedure using nonlinear contact analysis. Results The stresses were concentrated in the defect of the enamel and dentin at the DEJ in the condition of lateral loading. As the defect length increased in size, the peak maximum principal stress（MPS） value and the magnitude of the stress field along the DEJ both increased. Conclusion Undermined cervical DEJ had a significant effect on the stress distribution in the buccal cervical region.
