Retrospective Study of Functional and Esthetic Outcomes Using Narrow-Diameter Implants for Single Upper Central Incisor Replacements

Abstract

Objectives: The upper central incisors play a central role in esthetics, symmetry, and function. The purpose of this study is to evaluate the use of narrow-diameter implants (NDIs) for replacing single missing upper central incisors, addressing the gap in research regarding specific tooth types and their esthetic outcomes. Methods: This retrospective study included adult patients with a single missing upper central incisor replaced by NDIs. Exclusion criteria included patients who lost adjacent teeth during follow-up and patients with non-loaded implants. The primary outcome was peri-implant bone stability, while secondary outcomes included implant survival, technical complications, patient satisfaction, and esthetic evaluation using the Pink Esthetic Score (PES) and the White Esthetic Score (WES). Descriptive statistical analysis was performed. Results: A total of 64 NDIs were placed in 64 patients (mean age 55 ± 15 years; 40 females, 24 males). Implant diameters were 3.3 and 3.5 mm, with lengths ranging from 6.5 to 11.0 mm. The mean follow-up period was 42 ± 19 months. Marginal bone loss was -0.7 ± 0.9 mm mesially and -0.5 ± 0.7 mm distally. No implant failures were recorded. Esthetic outcomes were satisfactory, with a mean PES of 7.0 ± 2.6 and a mean WES of 7.9 ± 2.0. Conclusions: NDIs demonstrated high survival rates, marginal bone stability, and acceptable esthetic outcomes in the replacement of single upper central incisors.

Keywords: esthetic zone; implant survival; marginal bone level; narrow-diameter implants; single-tooth implant; upper central incisor.

Figure 1

Periapical radiograph showing the measurement of marginal bone level. The known implant length was used to calibrate the radiographic measurements. Then, the mesial and distal marginal bone levels (MBLs) were measured.

Figure 2

Clinical case treated by a single-unit narrow-diameter implant. (A) Clinical picture showing the baseline condition with the diagnosis of hopeless tooth #2.1 due to endo-periodontal disease. (B) The provisional prosthesis. (C) The definitive prosthesis. (D) The definitive prosthesis at higher magnification. (E) Periapical radiograph showing the insertion of the 3.5 mm × 8.5 mm dental implant. (F) Periapical radiograph at the implant loading. (G) Periapical radiograph after three years of implant insertion.

Figure 3

Clinical case treated by a single-unit narrow-diameter implant. (A) Clinical picture showing the baseline condition with missing #1.1 replaced by a fixed prosthesis. (B) The provisional prosthesis. (C) The definitive prosthesis. (D) Periapical radiograph showing the insertion of a 3.3 mm × 7.5 mm dental implant. (E) Periapical radiograph at the implant loading. (F) Periapical radiograph after four years of implant insertion.