Abstract
OBJECTIVES: This study aimed to investigate the impact of Twin Block appliances on intracranial pressure (ICP) in adolescents by measuring the optic nerve sheath diameter (ONSD) using ultrasonography. METHODS: We conducted a prospective study involving 20 adolescents (8 girls and 12 boys) with skeletal mandibular retrognathia undergoing treatment with Twin Block appliances. ONSD measurements were taken at six different time points: before appliance placement (T0), 1 min after placement (T1), 10 min after placement (T2), one month after the start of treatment with twin block (T3), immediately after appliance removal (T4), and 10 min after removal (T5). Mean arterial pressure (MAP), heart rate, and peripheral oxygen saturation (SpO2) were also monitored. Statistical analyses were performed using Friedman and Wilcoxon Signed-Rank tests with Bonferroni correction, considering p < 0.05 as statistically significant. RESULTS: Significant increases in ONSD were observed at T1 and T2 compared to T0 (p < 0.05), with the highest ONSD recorded at T1. No significant changes in ONSD were noted at T3 or T5, indicating that the initial increase in ONSD was temporary. MAP showed a significant decrease at T2, but no significant changes were observed in SpO2 or heart rate across the time points. CONCLUSION: This study is the first to report a significant increase in ICP, as indicated by ONSD, in adolescents using Twin Block appliances. The observed rise in ONSD shortly after appliance placement suggests a temporary increase in ICP. These findings highlight the importance of monitoring intracranial pressure during orthodontic treatment, particularly in adolescents.