A Novel Pneumatic Gingival Retraction: A Self-Controlled Clinical Trial

To address the clinical challenges of tissue injury, pain, and digital matching limitations associated with traditional gingival retraction cords method, we first proposed a novel pneumatic gingival retraction-scanning technique (PGR-S) based on the clinical observation of using three-way syringe airflow to painlessly and non-invasively displace free gingival. This study achieved clinical innovation through two core technological breakthroughs: (1) establishing a scanning-airflow integrated system, and (2) developing a polar coordinate-based point cloud stitching algorithm based on dynamic normal distance discrimination. A prospective self-controlled clinical trial (n = 60) was conducted to compare the effectiveness and Participants' experiences of PGR-S, cord-retained scanning method (GC-S), and conventional cord-removed silicone impression method (GC-I). Operation time was compared between PGR and GC placement. Statistical analysis revealed significant main effects of technique type, tooth position, and buccal/lingual location on gingival retraction effectiveness (P < 0.05), with PGR-S demonstrating superior performance (302.9 ± 124.9 µm). All subjective evaluation metrics (comfort, pain, nausea, and dryness) showed significant differences among thePGR-S, GC-S, and GC-I (P < 0.001). The PGR-S group exhibited enhanced comfort but increased tissue dryness, and operative time for PGR (70.48 ± 17.90 s) was significantly shorter than for GC techniques (194.78 ± 42.81 s; P < 0.001). The novel PGR-S demonstrated superior gingival retraction effectiveness, shorter operating time, and improved patient comfort compared to traditional methods. However, further optimization is required to address tissue dryness.