Detection of misfits at the abutment-crown interface: comparison between stationary intraoral tomosynthesis and periapical radiography acquired with different vertical angulations

OBJECTIVES: To compare the diagnostic accuracy of stationary intraoral tomosynthesis (s-IOT) with periapical radiography (PA) for misfit detection at the abutment-crown interface, across different misfit magnitudes and vertical angulations. METHODS: Twenty prototype sets of maxillae and mandibles with implants placed in the maxillary central incisor region were used, and ceramic copings were fabricated. Misfits of 50, 100, and 150 μm were simulated by interposing 50-μm-thick polyester strips at the abutment-crown interface. The group without +simulated misfit had no strips. PA and s-IOT images were acquired using 3 different vertical X-ray tube angulations: perpendicular to the implant (0°), positioned inferiorly (-10°), and superiorly (+10°). Five oral radiologists evaluated 480 images using a 5-point scale. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were analysed using repeated measures ANOVA and Tukey's post-hoc test (α = 5%). RESULTS: No significant differences were observed between PA and s-IOT (P > .05). AUC at 50 µm was significantly lower than 100 µm for all vertical angulations, and than 150 µm for -10° and +10° (P < .05); 100 µm was also lower than 150 µm for +10° (P < .05). +10° showed lower AUC than 0° and -10° at 50 µm, than 0° at 100 µm, and than -10° at 150 µm (P < .05). Sensitivity increased with misfit magnitude; 100 µm and 150 µm were higher than 50 µm for -10° and +10° (P < .05). +10° showed lower sensitivity than 0° at 50 µm and -10° at 150 µm (P < .05). Specificity varied only by vertical angulation; 0° showed the lowest values (P < .05). CONCLUSION: PA and s-IOT demonstrated comparable performance, +10° exhibited the lowest accuracy, and larger misfits were more easily detected. ADVANCES IN KNOWLEDGE: s-IOT provides additional bucco-lingual information; however, PA demonstrated comparable diagnostic accuracy in detecting misfits at the abutment-crown interface while exposing patients to lower radiation doses. Additionally, when ideal parallelism cannot be achieved, directing the X-ray beam towards the implant apex, rather than the prosthetic crown, may optimize misfit detection.