Study on the influence of fixed dental prostheses on radiotherapy dose distribution based on dual-layer detector spectral CT imaging.

OBJECTIVE: Dental prostheses are often removed before radiotherapy due to metal-induced artifacts, impairing patients' quality of life. This study evaluated five non-metallic materials for fixed prostheses in head and neck radiotherapy. METHODS: Full crowns made of zirconia, lithium disilicate glass-ceramic, resin-matrix ceramic, PEEK, and PMMA were placed on an in vitro model with natural teeth as a control. Spectral CT scanning with and without artifact reduction was performed. Dose distributions for 6 MV and 10 MV photon beams were calculated using convolution superposition. RESULTS: Artifact reduction significantly altered dose distributions for all materials (P < 0.001). Without artifact reduction, only zirconia differed from natural teeth (P < 0.001). After artifact reduction, no material showed significant difference from the control. Artifact-induced dose error was largest for zirconia, followed by resin-matrix ceramic and glass-ceramic, while errors for PEEK and PMMA were negligible. CONCLUSION: Zirconia is unsuitable due to severe artifacts. PEEK and PMMA are recommended for provisional crowns. Lithium disilicate glass-ceramic and resin-matrix ceramic are suitable for definitive restorations in radiotherapy patients.