Abstract:

Objective To investigate the accuracy and clinical efficacy of a novel strategy—zigzag scanning guided by marking lines—in the fabrication of direct digital custom trays for maxillary edentulous jaws. Methods An ex vivo experiment and a clinical trial were carried out. The ex vivo experiment selected a standard maxillary edentulous model and was comprised of a reference model group(RM), a control model group (CM), and an experimental model group(EM). The clinical trial was comprised of a conventional impression group(CP), an indirect digital impression group(IP), and an experimental direct digital impression group(EP). The experimental groups employed marking lines combined with a zigzag scanning path to acquire digital preliminary impression data. Three-dimensional deviation analysis was used to compare trueness and precision among groups, while a visual analog scale assessed clinicians’ satisfaction with the custom trays. Results In the standard model, the EM group demonstrated significantly superior trueness compared to the CM group(P<0.05), with no significant difference in precision. In the clinical trial, the EP group showed significantly better trueness for preliminary impressions than the IP group(P<0.05), with final impression quality comparable to the CP group. Clinician satisfaction evaluations revealed that both the IP and EP groups scored significantly higher than the CP group in border molding, and the EP group received the highest score in overall satisfaction(P<0.05). Conclusion The zigzag scanning guided by marking lines effectively improves the accuracy of direct digital preliminary impressions for maxillary edentulous jaws, enhances border adaptation of custom trays, and increases clinical operational satisfaction, demonstrating promising clinical applicability worthy of widespread adoption.

Key words: digital impression, edentulous jaw, intraoral scanning, new scanning strategy, accuracy