Hybrid Fabrication of Patient-Specific Intraoral Stents for Head and Neck Radiotherapy: A Retrospective Case Series with Exploratory Dosimetry

Abstract Background Patient-specific intraoral positioning stents enable targeted positioning of the jaws and soft tissues during radiotherapy for head and neck tumors. Combining functional molding with digital manufacturing extends the scope for adaptation to the patient’s dental status, including complete edentulism and postoperative anatomical changes. This study aimed to present a hybrid stent fabrication workflow and evaluate its clinical application and effects on the calculated dose distribution. Methods A retrospective descriptive case series examined fabrication and clinical use of individualized intraoral stents in 16 adults with head and neck tumors. Functional silicone templates were molded intraorally, digitized by extraoral optical scanning, and reproduced in polylactic acid by three-dimensional printing. Manufacturing and clinical records were reviewed descriptively. Whole oral-cavity mean dose was evaluated in seven paired comparisons with and without the stent. Serial sagittal kV-CBCT images from three illustrative patients were assessed qualitatively. Results Patient-specific intraoral positioning stents were used for caudal tongue displacement in 13 patients, lip retraction in two, and cheek retraction in one. Two patients were completely edentulous in both jaws. Whole oral-cavity Dmean decreased in five of seven paired comparisons; the average decreased from 44.11 to 42.94 Gy, a mean paired reduction of 1.17 Gy. The largest reduction was 5.2 Gy (9.3%) in patient 12, whose uninvolved oral-cavity Dmean also decreased by 3.3 Gy (7.3%). Reported PTV coverage was unchanged in all three detailed pairs. Dose changes in other organs were heterogeneous, including increases in selected structures. Serial images showed broadly similar jaw opening and tongue–palate separation across the illustrated fractions. Eleven patients completed radiotherapy with the stent. No device breakage or intolerance was reported; one stent was reworked before treatment for comfort. Conclusions The hybrid workflow enabled individualized tissue positioning across diverse dental and postoperative conditions, including complete edentulism. The paired comparisons support a selective dosimetric benefit: lower average oral-cavity exposure in most evaluated pairs, with no decline in reported target coverage in the three detailed comparisons. These findings, together with the illustrated anatomical separation and clinical usability, support prospective evaluation of patient-specific stents as an adjunct to treatment planning. Reduced clinical toxicity and superiority over independently optimized plans were not established.