Implant function as well as implant esthetics represent the determining issues of importance for patients seeking dental implant therapy. In the present thesis scientific emphasis is put on biomechanical insights and esthetic considerations to optimize implant therapy outcome. In the biomechanical part of the thesis, influence of crown-to-implant ratios on peri-implant bone will be discussed (study I). Impact of low and high insertion torque on tissue alterations at the crestal peri-implant area will be investigated by clinical, radiological and biochemical examinations (study II). The second part of the thesis addresses subjective and objective assessment of peri-implant soft tissue esthetics following immediate-, early- and delayed implant placement in the anterior maxilla (study III), in the anterior mandible (study IV) as well as following autologous bone grafts (study V). ^Results of study I indicate that higher clinical crown-to-implant ratios of implant-supported restorations may be regarded as major contributing factors to marginal bone loss in the first year of functional loading. Increasing the implant length could reduce stress values around the crestal peri-implant area and thus, minimizing marginal bone loss. By contrast, no solitary impact of insertion torque and implant neck design on marginal bone loss in the lower mandible was observed following the first year of implant placement (study II). Favourable esthetic outcomes following different treatment protocols (immediate-, early-, delayed implant placement) were achieved using objective and subjective assessment criteria (study III). Patients were less critical towards implant esthetics, however, would prefer shorter treatment times, if applicable. Immediate implant placement should only be performed in well-selected patients as it carries potential risks of impairing overall esthetics due to papilla absence, midfacial soft tissue displacement as well as soft tissue discoloration. Tulip-shaped double crowns as well as single crowns can be successfully used in the lower anterior mandible (study IV). Regarding the esthetic outcome tulip-shaped restorations performed significantly worse using objective assessment criteria, however, no difference in patient satisfaction was observed. Soft tissue esthetics following autologous bone grafts were comparable to data reported following immediate and early implant placement (study V). Regardless the implant protocol used satisfactory esthetics can be achieved.