Clinical effectiveness of FDM-printing and silicone test in shaping the gingival contour in immediate prosthetic protocols

Abstract

Controlled formation of the gingival contour is a key factor in the success of immediate prosthetic protocols, determining both functional and aesthetic outcomes of treatment. However, to date there have been no standardized methods for quantitative assessment of the pressure exerted by temporary restorations on soft tissues. Objective: To evaluate the clinical effectiveness of applying FDM-printing and the silicone test for individualized correction of the pontic area in temporary prosthetic restorations during immediate prosthetic treatment. Materials and methods. The study included 20 patients (12 women, 8 men; aged 24—67 years) who underwent immediate prosthetic rehabilitation after tooth extraction or implantation. Patients were divided into 2 groups: main group — FDM modification of the pontic area of the provisional restoration, with the silicone test used to assess soft-tissue contact and guide adjustment of the restoration; control group — standard CAD/CAM protocol without FDM modification; the silicone test was performed solely for research measurements and between-group comparison, and its results were not used to adjust the restoration or modify the clinical decision-making process. Silicone film thickness was quantitatively assessed in both groups using the silicone film thickness analyzer in five anatomical zones: mesial, distal, vestibular, oral, and central. In the main group, the measurements were used to guide clinical adjustment of the pontic area, whereas in the control group they were recorded exclusively for research purposes and statistical analysis. Evaluated parameters included adaptation of soft tissues, blanching severity, need for correction, patient satisfaction, and complication rates. Results. The median mean silicone film thickness across five zones was 84 μm in group I and 162 μm in group II (p<0.001). Minimum film thickness showed a strong inverse correlation with blanching severity (ρ=−0.918; p<0.001), whereas the number of zones<60 μm showed a strong positive correlation with blanching (ρ=0.853; p<0.001). The number of zones outside the target range of 60—150 μm negatively correlated with the clinician-reported fit score (ρ=−0.888; p<0.001) and the integrated patient-reported score (ρ=−0.908; p<0.001). Persistent blanching for more than 20 minutes was not recorded in group I and was observed in 6 patients in group II (p=0.011). Unscheduled correction was required in 1 patient in group I and in 6 patients in group II (p=0.057). The integrated patient-reported score was 8.73 and 6.83 points, respectively (p=0.003), and the clinician-reported fit score was 9.14 and 6.77 points (p=0.002). Conclusion. The use of FDM printing combined with the silicone test enables quantitative assessment of the contact between a provisional restoration and soft tissues and allows these data to be used for individualized correction of the pontic area. In the studied sample, the proposed protocol was associated with more favorable early clinical outcomes, a lower frequency of prolonged blanching, and a numerically lower need for unscheduled corrections. The results are preliminary and require confirmation in studies with larger samples.