Orthodontic treatment outcomes and safety for secondary dentofacial deformities after childhood cancer therapy: a systematic review and meta-analysis.

AIMS: To systematically evaluate the treatment outcomes and safety of orthodontic intervention for secondary dentofacial deformities after childhood cancer therapy, with particular emphasis on occlusal outcomes, oral health-related quality of life, treatment-related complications, and dental developmental abnormalities relevant to orthodontic management. METHODS: A comprehensive search of PubMed, Embase, Cochrane Library, Web of Science, Scopus, and CINAHL was performed using terms related to cancer, orthodontic treatment, and treatment outcomes. Eligible studies included observational or comparative clinical studies reporting either treatment efficacy outcomes (e.g., w-PAR, ICON, and oral health-related quality of life) or treatment safety/sequelae outcomes (e.g., treatment-related complications and dental developmental abnormalities). Risk of bias was assessed using the Newcastle-Ottawa Scale. For efficacy outcomes, pooled standardized mean differences with 95% confidence intervals were calculated; for safety/sequelae outcomes, pooled risk ratios with 95% confidence intervals were estimated. Random-effects models were applied in Stata, and heterogeneity was assessed using Cochran's Q and the I2 statistic. RESULTS: Ten studies published between 2001 and 2023 were included. For w-PAR, the pooled effect showed a significant overall change (SMD = -1.12, 95% CI -2.22 to -0.01; I2 = 98.5%), driven mainly by the immediate post-treatment subgroup. For ICON, the pooled effect was also significant (SMD = 0.68, 95% CI 0.12 to 1.24; I2 = 97.5%), with the stronger signal observed at follow-up beyond 3 weeks. Oral health-related quality of life, assessed by OHIP-14, showed a small but significant overall improvement (SMD = 0.26, 95% CI 0.03 to 0.49), with moderate heterogeneity (I2 = 54.3%). In contrast, survivors experienced a significantly higher risk of complications during orthodontic treatment than comparison groups (RR = 2.44, 95% CI 1.07-5.58; I2 = 36.7%). The pooled relative risk of dental developmental abnormalities relevant to orthodontic planning was not significantly different overall (RR = 1.11, 95% CI 0.40-3.08), although heterogeneity was considerable (I2 = 90.3%). CONCLUSION: Orthodontic intervention in survivors of childhood cancer may be associated with improvements in occlusal outcomes and oral health-related quality of life; however, the evidence for treatment efficacy remains uncertain, largely due to substantial between-study heterogeneity. At the same time, survivors appear to have a significantly increased risk of treatment-related complications.