Methods of incisor inclination control during the non-accelerated retraction of upper anterior teeth with fixed orthodontic appliances: a systematic review and meta-analysis

Background Protrusion of the maxillary incisors represents a frequent clinical challenge in orthodontic treatment. Current systematic reviews are limited in range and methods employed, while individual trials lack consensus on the most effective mechanics for retraction.Objective This systematic review aimed to evaluate the effectiveness of various approaches used to control anterior tooth inclination during non‑accelerated retraction with buccal fixed appliances.Methods A search of databases was conducted in September (2025) to identify randomized controlled trials using various methods and techniques to retract the upper anterior teeth. Eligible RCTs enrolling patients aged 12-35 years who underwent extraction of upper first premolars were included. Meta‑analyses used random‑effects models (RevMan 5.3). Certainty of evidence was appraised with GRADE.Results Twenty RCTs with 568 patients in total were included. Risk‑of‑bias was low in 11 trials, some concerns in 4, and high in 5. Pooled analyses showed that retraction produced clinically and statistically significant palatal crown inclination of the upper incisors across techniques: sliding en‑masse (MD ≈ - 9.8°; moderate certainty), loop‑based en‑masse (MD ≈ - 13.3°; moderate certainty), and two‑step retraction (MD ≈ - 8.9°; moderate certainty). Loop‑based mechanics were associated with slightly greater retroclination than sliding (MD = 2.49°; statistically significant but not clinically meaningful; moderate certainty). Comparisons of en‑masse versus two‑step retraction showed no significant difference (very low certainty). Vertical incisal changes were inconsistently reported and supported by very low‑certainty evidence. Heterogeneity varied from low to considerable across analyses.Conclusion Anterior teeth retraction is generally associated with clinically meaningful incisor retroclination. Loop-based mechanics appear to produce slightly greater retroclination than sliding, but the clinical relevance is limited. Evidence quality ranges from moderate to very low, and heterogeneity could not be avoided; high‑quality RCTs with standardized inclination measurements are needed to define optimal inclination‑control strategies.Trial registration The review protocol was prospectively registered with PROSPERO (CRD420251167359) during the early stages of the review process.