Esthetic, Periodontal, and Functional Outcomes of Orthodontic Space Closure Versus Prosthetic Replacement for Congenitally Missing Maxillary Lateral Incisors: A Systematic Review.

Congenital absence of the maxillary lateral incisors is a common developmental anomaly that may compromise smile esthetics, periodontal health, and occlusal function, and it is typically managed by either orthodontic space closure with canine substitution or space opening followed by definitive prosthetic replacement. This systematic review aimed to compare esthetic, periodontal, and functional/occlusal outcomes between these two treatment approaches. A systematic search of PubMed, the Cochrane Library, LILACS, and Semantic Scholar was conducted from inception to 4 December 2025 in accordance with PRISMA 2020. Eligible studies included comparative clinical and cross-sectional designs reporting at least one relevant outcome domain; no randomized controlled trials were identified. Screening and data management were performed using Rayyan, risk of bias was assessed using ROBINS-I, and certainty of evidence was evaluated using the GRADE approach; due to substantial heterogeneity in study designs and outcome measures, meta-analysis was not performed, and findings were synthesized narratively. The search identified 1,244 records; after removal of 284 duplicates, 960 records were screened, 113 full texts were assessed, and 19 studies were included (18 retrospective and one prospective). Fifteen studies assessed esthetic outcomes, seven evaluated periodontal outcomes, and six reported functional/occlusal outcomes, using combinations of clinical examinations, photographic assessments, questionnaires, and cast/model analyses. Overall, orthodontic space closure yielded esthetic outcomes that were frequently acceptable to patients and lay observers. Periodontal findings were generally comparable across approaches, with prosthetic restorations more often associated with localized plaque-retentive challenges, and functional/occlusal outcomes appeared broadly similar without consistent evidence of increased temporomandibular dysfunction attributable to either modality. Most studies demonstrated moderate to serious risk of bias, and the overall certainty of evidence was low. Within these limitations, both strategies appear clinically acceptable, while orthodontic space closure may offer favorable periodontal profiles and esthetic acceptability, particularly from the lay perspective, while avoiding certain long-term prosthetic-related complications, underscoring the need for higher-quality prospective comparative research.