Gingival Recession After Combined Orthodontic–Orthognathic Treatment: A Systematic Review of Clinical Studies with Emphasis on Mandibular Incisors and Adjunctive Periodontal Therapies

Background and Objectives: Combined orthodontic–orthognathic treatment is the standard approach for managing severe dentofacial deformities. Nevertheless, its potential impact on periodontal tissues, particularly gingival recession (GR), remains a matter of clinical concern. This study aimed to evaluate the relationship between orthodontic–orthognathic procedures and GR based on available clinical evidence, with particular focus on potential risk modifiers, including orthodontic mechanics, surgical factors, and periodontal phenotype. Materials and Methods: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. The review question was formulated using the PICO framework. Results: Seven observational clinical studies were included, with sample sizes ranging from 24 to 40 patients. GR outcomes varied considerably according to surgical procedure, orthodontic mechanics, adjunctive therapies, and patient-specific factors. Overall certainty of evidence was low–moderate. Conclusions: GR following combined orthodontic–orthognathic treatment is inconsistently reported and influenced by multiple clinical variables. Evidence suggesting roles for periodontal phenotype and adjunctive therapies, including PAOO, remains limited and context-dependent. Overall certainty of evidence is low–moderate, and findings should be interpreted cautiously.