EFFECTS OF NASOALVEOLAR MOLDING ON MAXILLARY ARCH DIMENSIONS AND MORPHOLOGY IN UNILATERAL AND BILATERAL CLEFT LIP AND PALATE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Objective: The aim of this study was to determine whether nasoalveolar molding (NAM) produces temporary improvement or stable changes in maxillary arch growth and orientation. Materials and Methods: A systematic search of ISI (Web of Science), PubMed, Scopus, EMBASE, and Cochrane CENTRAL databases was conducted for studies indexed up to July 2025 following PRISMA guidelines. Six eligible studies were included, five on unilateral cleft lip and palate (UCLP) and one on bilateral cleft lip and palate (BCLP). Data on Anterior Arch Cleft Width (AACW), Posterior Arch Width (PAW), and Intercanine Width (ICW) were extracted and pooled for meta analysis. Standardized Mean Difference (SMD) was calculated, and a random effects model was applied when heterogeneity was present. Statistical significance was set at p < 0.05. Results: NAM produced notable short term changes in maxillary arch morphology before lip surgery. Most studies reported a significant reduction in anterior cleft width (AACW) in the NAM group compared with controls. Trends toward decreased intercanine width (ICW) and increased posterior arch width (PAW) were also observed, although these changes were not consistently statistically significant. No meaningful differences were found for middle arch width (MAW) or alveolar arch length (AAL). One long term follow up study suggested that some structural improvements may persist for several years, although natural growth, subsequent surgeries, and individual variability may influence outcomes. Meta analysis confirmed a significant short term reduction in AACW (SMD = 4.105, 95% CI = 1.961–6.249, p = 0.000), while no significant effects were found for other parameters. The reduction in AACW was less pronounced in BCLP than in UCLP patients. Conclusion: This study showed that NAM significantly reduces anterior cleft width before lip surgery, while its effects on other arch dimensions remain inconsistent. Evidence for bilateral cleft lip and palate and long term outcomes is limited, highlighting the need for further high quality research.