| Abstract: This lecture provides a critical comparison between fixed and removable orthodontic appliances, focusing on evidence-based selection criteria and clinical indications. Emphasis is placed on transverse and vertical dimension management, highlighting how appliance choice affects treatment efficacy, efficiency, patient compliance, and risk of complications. The cost–benefit ratio of each modality is critically evaluated in expansion and anterior open bite treatment protocols. The session aims to guide clinicians toward more efficient, cost-effective, and outcome-driven appliance selection for transverse and vertical correction in clinical practice. |