Pain Experience During Rapid Maxillary Expansion: A Prospective Observational Study

<b>Aim:</b> Rapid maxillary expansion (RME) is a widely used interceptive orthodontic procedure in pediatric patients that is often associated with discomfort and pain, particularly during the initial phase of treatment. The present study aims to analyze the intensity and temporal trend of pain perceived by pediatric patients undergoing rapid palatal expansion (RME) by evaluating the influence of factors such as age, sex, type of maxillary transverse deficit, palatal expander, and dental anchorage. <b>Materials and Methods:</b> A prospective observational study was conducted on 134 pediatric patients (mean age 8 years; range 6-14 years) diagnosed with transverse maxillary contraction. Patients were treated with tooth-borne Haas or Hyrax expanders. Pain perception was monitored daily using a specific questionnaire with answers based on the Wong-Baker FACES scale. Collected data were analyzed by using the ANOVA test (<i>p</i> < 0.05). <b>Results:</b> Pain was a common symptom, with greater intensity in the first days of treatment. The Hyrax expander was associated with significantly greater initial pain than the Haas one (<i>p</i> < 0.001). Tooth-borne expanders on the first permanent molars resulted in greater initial pain than anchorage on the second primary molars (<i>p</i> < 0.001). Patients with unilateral posterior crossbite and anterior crossbite reported higher average pain levels (<i>p</i> < 0.001). Age emerged as a significant modulator of pain (<i>p</i> < 0.001), while no significant differences were found based on sex (<i>p</i> = 0.287). <b>Conclusions:</b> Expander type, tooth-anchorage type, maxillary transverse contraction type, and patient age significantly influenced pain perception during pediatric RME. These results provided useful indications for the clinical management of the patient, for the choice of expander and anchorage type and for the timing of intervention.