Development and Expert Content Validation of a Pop-up Laser-assisted Cone-positioning Device for Periapical Radiography

Abstract

Positioning errors in periapical radiography, particularly cone cut and beam misalignment, remain recurrent technical problems that may compromise image adequacy, increase repeat exposure, and reduce the reliability of radiographic interpretation. Although operator training and conventional positioning aids may reduce selected errors, alignment control remains challenging in the bisecting-angle technique because of anatomical variation, restricted intraoral access, and sensitivity to vertical and horizontal angulation. This study aimed to develop a pop-up laser-assisted intraoral X-ray cone-positioning device and to establish its early-stage expert content validation before usability or clinical performance testing. A research and development design was employed in two sequential stages: prototype design and fabrication, followed by expert content validation. The prototype consisted of three principal modules: a remote motor, a controller box, and a laser module configured with dot/cross projection to support pre-exposure cone alignment. A multidisciplinary technical panel representing physics, optical-electronic engineering, and manufacturing/metrology conducted content validation using a structured five-point rating instrument covering structural quality, usage qualities, management qualities, and generic environmental qualities. The validation profile was consistently favourable, with all indicator scores ranging from 4.00 to 5.00. The overall mean score across all indicators was 4.62/5.00, and the complementary Content Validity Index analysis showed I-CVI = 1.00 for all indicators, with S-CVI/Ave = 1.00. Structural quality achieved the highest domain score, while lower but still favourable scores in understandability, learnability, maintainability, accountability, and autonomy identified specific refinement priorities. The findings indicate that the prototype achieved an acceptable level of design readiness and technical-content validity. The findings support further usability testing and controlled radiographic evaluation; no claim of clinical effectiveness is made at this stage.