Purpose: The aim of this study was to identify factors associated with failure of maxillary and mandibular dental implants before permanent crown placement. Materials and methods: The present study included adults who underwent dental implantation between January 2003 and December 2016. Implant failure before the permanent prosthesis placement was defined as early implant failure. Patients were divided retrospectively into groups according to the status of their implants; ie, a group with no early implant failure and a group with at least one early failure. Patient-related and implant site-related factors were analysed. Results: 18 (4.8%) of the 376 patients had at least one implant that failed early. 49 (4.7%) of the 1,050 implants included in the study failed early. After adjustment, significant risk factors associated with early failure of maxillary implants included age, bone regeneration for insufficient bone, and signs of postoperative infection. In the mandibular implants, the only significant risk factor for early failure after adjustment was postoperative infection signs. Conclusions: The risk factors associated with early implant failure differed between the maxilla and mandible. Early failure was more attributed to these causes than to a difference in morphology or bone quality between the maxilla and mandible. Prospective studies focusing on the interaction between these risk factors are needed. Keywords: complications, early implant failure, implants, sinus elevation, smoking The author declares no conflicts of interest related to this study.