In the ﬁrst 25 years of modern implant dentistry based on the concept of osseointegration (15, 96), implant placement was predominantly performed in healed sites of fully edentulous patients (1, 16). Most of these patients had been edentulous for years and the utilization of dental implants was aimed at improving masticatory function and the quality of life. In the 1980s, the application of dental implants started to be cautiously expanded into partially edentulous patients as well, and the ﬁrst reports were published with promising results (27, 28, 104). Since then, the percentage of partially edentulous patients in implant dentistry has signiﬁcantly increased and today, these indications predominate in daily practice, in particular single tooth gaps (12, 19). In the case of single tooth replacement, implant placement into healed sites has today completely lost its dominance, since the thorough understanding of dimensional ridge alterations post extraction (3, 34) revealed that this approach frequently complicates therapy, and a healing period of at least 6 months post extraction prior to implant placement is not really attractive any more to patients in daily practice.