Radiographic Determination of Implant-Specific Biologic Widths in the Canine Model

Objectives: Despite variable degrees of alveolar crest remodeling for different implants, necessary distances when placing implants next to natural teeth or other implants have been assumed.  Frequently, this results in unfavorable crestal morphology that leads to impaired development of interdental papillae and eventually, to an esthetic compromise of prosthesis.  This study involves determination of the biologic widths, heights, and angles of “bony cuffs” of various implants, areas of the peri-implant osseous tissue at the alveolar crest, in attempts to determine an ideal implant-specific placement protocol.

Methods: The project is a prospective randomized descriptive experimental study.  Sixty 3i Osseotite® standard, wide and XP implants were randomly placed in 5 Mongrel dogs using the standard protocol.  Following abutment attachments, standardized radiographs were made at baseline, then 4-week intervals for 2 months. Linear dimensions on each digitized implant image were measured with Image-Pro Plus on 3 separate occasions by one calibrated examiner.  Measurements were collected from the abutment-fixture junctions to the first bone contact both vertically and horizontally.  All values were averaged and evaluated with  ANOVA.

Conclusions:  There are statistically significant differences (p<0.05) between times for all types of implants which demonstrate that the remodeling is taking place as expected.  XP implants show greatest amounts of apical bone resorption, whereas bone structures around standard and wide implants resorb more horizontally.  There appear to be implant-specific differences with respect to biologic widths, heights, and angles within the limits of this study.