Conometric Single Restorations with Prosthetic Margin Below the Bone Crest: A Case Series

The purpose of this prospective case series is to present radiographic and clinical results of single implant-prosthetic rehabilitation with conometric retention, in which the connection abutment - prosthetic crown is located below the bone level. A total of 10 sites with single edentulism were rehabilitated with subcrestal implants and prosthetic crowns with conometric retention. Crestal bone levels and peri-implant soft tissue conditions were evaluated for each implant. Hard tissue measurements were performed using parallel intraoral radiographs immediately after implant insertion, at the placement of the restoration, after 1 year and 2 years of full functional load. After 2 years of follow-up all the rehabilitations appear clinically and radiographically stable. Mean vertical bone loss was 0.1 mm after 2 years of loading. Mean horizontal bone loss from the abutment-cap interface was 0.59 mm for distal side and 0.21 mm for the mesial side. Within the limitations of this study, the results suggest that conometric connection both at the implantabutment and abutment-crown interface allows us the freedom to position the margin of the prosthetic connection even below the bone crest.