Objective:To analyze the influence of two connection ways via ball cap and Locator on stress distribution of mandible

implants and abutments under different loading modes by establishing finite element models of edentulous mandibular four-implant-supported overdenture. Methods:The cone beam computerized tomography（CBCT）data of edentulous mandibular patients were collected

and three-dimensional finite element models of implant-supported overdenture via ball cap and Locator connections were established respectively by Mimics

Gomagic Studio

SolidWorks software

and stress distribution on the mandible

implants and abutments under different loading modes was analyzed combined with ANSYS software. Results:（1）Under different loading modes

stress concentration was found on cortical bone of the neck of implants and lower margin of mandible median lingual region via the two connection ways

but the max equivalent stress（von Mises stress）was located on cortical bone of lower margin of mandible median lingual region.（2）Stress concentration was found on the neck of implants and the contact zone of implants and abutments.（3）Stress of the above areas of stress concentration via Locator connection was lower than that of ball cap connection under the same loading mode. Conclusion:（1）The max von-Mises tress of four-implantsupported overdenture is located on cortical bone of lower margin of mandible median lingual region

rather than cortical bone the neck of implants.（2）The von-Mises tress of overdenture by Locator connection is lower than that of ball cap connection;overdenture via Locator connection is more favorable to the physical health of alveolar bone and long-term persistence of implants.