Determinants of Esthetic Outcomes in Single-Tooth Implant Therapy: A Systematic Review of Randomised Controlled Trials

Abstract

Objectives. To integrate evidence from studies on how the timing of implant placement, management of peri-implant soft tissue, the implant surface and macro design, abutment design and materials, and the method of retention of the prosthesis, affect the objectively assessed esthetic results of single-tooth implants located in the esthetic zone. Methods. MEDLINE via PubMed was searched to August 5, 2026 in two phases. The first phase was a short six-line search to map the area and the second phase was the main search to determine eligibility. This was done using a combination of the outcome-instrument concept and a filter for randomized controlled trials. Randomized controlled trials including 10 or more adult participants, that described the placement of an implant-supported single anterior maxillary or mandibular implant, and assessed a validated esthetic index or measured the mid-buccal mucosal margin in months after the delivery of the final implant, were included in the review. The risk of bias was evaluated using RoB 2 and the certainty of evidence using GRADE. The reporting was according to PRISMA 2020. Results. The scoping search in this review identified 2305 results. The main search identified 96 results, of which 19 were excluded at title and abstract screening and 47 at full text screening. This left 28 studies across 30 reports (1146 patients, 1175 implants). Most studies addressed peri-implant soft tissue (10 studies) and abutment design (7 studies), while only 3 studies considered implant surface and macro design, and 2 studies considered retention. Twenty-one studies reported a single 12-month outcome. Three studies reported outcomes beyond 3 years. Independent esthetic evaluations were reported in 9 studies, and 19 studies reported outcome measures that were considered to pose a high risk of bias. All studies that considered a “hardware variable (implant neck design, macro design, crown and abutment materials, geometry, and abutment materials) reported a null result for the Pink Esthetic Score, including a study in which esthetic scores were similar despite significant marginal bone loss (2.01 ± 0.77 mm vs 0.90 ± 0.57 mm). Significant findings were reported in studies that considered soft tissue management, including: connective tissue graft (mid-facial mucosa +0.20 ± 0.70 mm vs −0.48 ± 1.13 mm, p = .014), open and closed healing (mean −1.49, 95% CI −2.36 to −0.62, p = .0014), and provisionalization (+1.6 PES points, 95% CI 0.8-2.4). Certainty was moderate for soft tissue management studies, and low to very low for the remaining studies. No meta-analysis was performed as the necessary conditions for pooling of studies were not met. Conclusions. When position and soft tissue are accounted for, selection of Components does not affect the aesthetic outcome. However, selection of the case and management of soft tissue do affect the outcome. Independent and standardized assessment of aesthetics and follow-up of more than five years are the main requirements of this published literature. Clinical significance. No measurable difference in aesthetics will be seen from selection of implant systems, abutment materials, or crown materials in an anterior site. Thus, clinicians should focus their planning efforts on the facial bone wall, the position of the implant in the three axes, and the volume of soft tissue. Systematic review registration: PROSPERO [CDR420261476473]