Digital vs. Analog Inputs in CAD/CAM Orthodontics: A Comparative Clinical Evaluation of Palatal Expander Fabrication Workflow

Overview

36 patients with unilateral or bilateral cross bite treated with hyrax expanders fabricated through three distinct workflows: fully conventional (physical impression + manual fabrication), hybrid (physical impression + CAD/CAM fabrication), and fully digital (intraoral scanning + CAD/CAM fabrication). To evaluate and compare the clinical fit, workflow efficiency, and patient/clinician satisfaction of palatal expanders fabricated using traditional, hybrid digital, and fully digital workflows.

This randomized, three-arm clinical trial aims to compare the clinical performance and workflow efficiency of tooth-borne palatal expanders fabricated using three different manufacturing workflows: fully conventional, hybrid digital, and fully digital. The study evaluates the impact of these workflows on appliance fit at delivery, efficiency of clinical and laboratory procedures, and patient- and clinician-reported satisfaction. Following enrollment, participants will be randomly allocated into one of three equal groups using a computer-generated randomization sequence. All appliances used in the study will be Hyrax-type maxillary expanders designed to deliver comparable transverse expansion forces, with differences limited to the fabrication workflow. In the fully conventional workflow, maxillary impressions will be obtained using conventional impression materials. Dental stone casts will be poured and used directly for appliance fabrication. The Hyrax expander will be manually fabricated on the physical cast using traditional laboratory techniques, including wire bending, band adaptation, and soldering or brazing of the expansion screw and components. In the hybrid digital workflow, maxillary impressions will also be taken using conventional impression materials and poured in dental stone. The resulting physical casts will then be digitized using a desktop optical scanner. The scanned models will be imported into computer-aided design (CAD) software, where the palatal expander will be digitally designed. Appliance fabrication will be completed using additive manufacturing (3D printing), followed by incorporation of the expansion screw as required. In the fully digital workflow, maxillary arches will be captured directly using an intraoral optical scanner. The generated virtual models will be used without producing a physical cast. Appliance design will be performed entirely within CAD software, and the Hyrax-type expander will be fabricated using 3D printing technology. At appliance delivery, clinical evaluation will be performed to assess accuracy of fit, seating on the teeth, need for adjustment, and overall clinical acceptability. Any required chairside modifications will be recorded. Workflow efficiency will be assessed by documenting clinical chairside time, laboratory production time, and the incidence of remakes or significant adjustments. Patient comfort and acceptance, as well as clinician satisfaction with appliance fit and handling, will be assessed using structured questionnaires. Data collected from all three groups will be compared to determine differences in clinical performance and workflow efficiency among conventional, hybrid, and fully digital fabrication approaches.