Purpose: Implant osseointegration has been well described, but coronal osseous healing continues to be investigated because of its impact on esthetic results and long-term maintenance. Although numerous implant diameters and designs exist, little is known about the role of these parameters on surrounding bone. Therefore, this study aimed at elucidating the influence of implant dimensions on crestal bone morphology. Materials and Methods: Sixty Biomet/3i implants (20 standard, 20 wide, and 20 expanded platform [XP]) were randomly placed in posterior quadrants of 5 mongrel dogs. After healing, exposure of the implants to the oral cavity, and euthanasia of the animals, samples were harvested. Histomorphometric measurements were performed to determine the bone cuff height, width, and angle, and analysis of variance was applied to compare groups. Results: Formation of a peri-implant cuff was noticed in all implant sites. Mean cuff height was 0.8 mm, 1 mm, and 1.4 mm for standard, wide, and XP implants, respectively. Mean cuff width was 1.9 mm, 2.1 mm, and 2.8 mm for standard, wide, and XP implants, respectively. These differences were statistically significant between wide and XP implants (P = .035), as well as between standard and XP implants (P = .001). Angle did not differ significantly between implants of different platform widths. Conclusions: Craterization after placement of healing abutments and a healing period was observed around all implants. Width and height of the cuff varied significantly with implant diameter and platform design, but the angle formed with the implant did not vary significantly. Keywords: animal study, bone healing, dental implants, implant diameter, osseointegration