The Use of a New Safe Angle Concept for Immediate Implant Placement in the Anterior Maxilla: A Cross-Sectional CBCT Study

Purpose: To introduce a new method for labiopalatal positioning and angulation of immediately placed dental implants in the anterior maxilla with relation to the type of abutment used (straight/angled abutment). Materials and Methods: CBCT scans from the database of a private practice were searched for patients who received immediate implants in the anterior maxilla. After superimposition of the initial and postoperative scans, the incisor root angle (IRA), incisor implant angle (IIA), and the difference between these angles were measured. An assessment was then made about whether the implant position would be within the safe angle or not. Age, sex, tooth/implant site, and type of prosthetic abutment (straight/angled) were retrieved from the patients’ records. Results: A total of 74 patients with 95 immediate implants altogether were selected for analysis. In regard to the type of abutment, 76 (80%) were straight, and 19 abutments (20%) were angled. Regardless of abutment type, 72 implants (75.8%) were placed within the safe angle, while 23 implants (24.2%) were placed outside it. All 19 implants with angled abutments were placed outside the safe angle. There were statistically significant associations between placement within the safe angle and type of abutment (P < .001; OR = 19), IRA (P < .001; effect size = 0.904), difference between IIA and IRA (P < .001; effect size = 1.209), and sex (P < .001; OR = 2.995). There was no statistically significant association between placement within the safe angle and IIA (P = .757, effect size = 0.063), site (P = .200; effect size = 0.184 ), or age (P = .387; effect size = 0.208). There was a statistically significant association between the type of abutment and the IRA (P = .001; effect size = 0.762) as well as the difference between IIA and IRA (P < .001; effect size = 1.056). Conclusions: The safe angle concept can be used as a reliable planning tool to determine the correct implant positioning for immediate implant placement in the anterior maxilla. Applying the safe angle concept will reduce the need for angled abutments for prosthetic correction.