Purpose: The purpose of this retrospective analysis of expert opinions was to optimize the level of patient information prior to implant-prosthetic treatment. Materials and Methods: Twenty-eight expert opinion reports on implant treatment cases compiled between 1996 and August 2001 were analyzed. Results: Seventy-five percent of all cases subjected to expert opinion reports revealed generally inadequate patient information. Significant associations were found between diagnostic mistakes and a lack of or inadequate information about complications that occurred (P = .04). Inadequate prosthetic or periodontal pretreatment of the patient prior to implant treatment was associated with a lack of information concerning implant and periodontal maintenance (P = .023) as well as insufficient oral hygiene status (P = .001). Discussion: In addition to a general lack of patient information, a lack of information about possible complications and inadequate information about treatment risks, treatment costs, and treatment alternatives were also found. Conclusion: Optimization of pretreatment information for patients, as well as improvement of communication with patients throughout the whole treatment and maintenance period, seem to be necessary.