Influence of interimplant distance on papilla formation and bone resorption: a clinical-radiographic study in dogs.

Implant esthetics has been the focus of attention for the past decade, and one vital issue is the effect of interimplant distance on interimplant papilla formation and crestal bone loss. The aim of this study was to evaluate the effect of 1, 2, and 3 mm of interimplant distance on papilla formation and crestal resorption in submerged and nonsubmerged Ankylos implants after prosthetic restoration. Bilateral mandibular premolars of 7 dogs were extracted, and after 12 weeks each dog received 8 implants. Implants were placed so that 3 interimplant distances were created at 1 mm (group 1), 2 mm (group 2), and 3 mm (group 3). The sides and the position of the groups were randomly selected. Twelve weeks after placement, the implants received metallic prostheses that allowed 5 mm of space between the prosthetic contact point (CP) and the crestal bone (CB). After 8 weeks, the distance between the CP and the papilla (CP-P) and the gingival height at the distal proximal aspect of the prosthesis (CP-DE) was clinically measured. Radiographic images were obtained to measure the distance of the CP to the CB within the interimplant surfaces (CP-IP) and adjacent to the edentulous surfaces (CP-ED). The clinical measurement of CP-P for submerged and nonsubmerged implants was 3.57+/-1.17 mm and 3.10+/-0.82 mm for group 1, 3.57+/-0.78 mm and 3.16+/- 0.87 mm for group 2, and 3.35+/- 0.55 mm and 3.07+/-0.93 mm for group 3. The CP-DE was 3.25+/-0.77 mm for submerged and 2.78+/- 0.64 mm for nonsubmerged implants. The CP-IP for the submerged and nonsubmerged implants was 6.91+/-0.95 mm and 7.68+/-2.73 mm for group 1, 7.46+/-1.43 mm and 5.87+/-1.71 mm for group 2, and 7.72+/-0.81 mm and 7.59+/-1.33 mm for group 3. The CP-ED was 6.77+/-1.33 mm for submerged implants and 6.03+/-1.58 mm for nonsubmerged implants. There were no statistical significant differences for any of the measured parameters. We conclude that when the distance from the CP to the CB was 5 mm, interimplant distances of 1 to 3 mm did not affect papilla formation or crestal resorption of submerged or nonsubmerged implants in the dog model.