P2023-0010

Artifact-Free Panoramic Dental X ray via Deep De Shadowing

Unmet need

Panoramic X‑rays suffer from inherent ghost jaw, spinal overlay, and pharyngeal air‑gap artifacts that obscure teeth, mandibular canal, TMJ, and lesions, risking missed or uncertain diagnoses.​ Current enhancement tools, such as contrast equalization, super‑resolution, GAN-based deblurring improve image quality but do not explicitly correct these projection artifacts.​ Clinicians often require CBCT to clarify third molar–mandibular canal relationships and hidden pathologies, increasing cost, radiation dose, and workflow burden.​

The technology

  • A two‑stage, fully automated AI pipeline
  • Runs in approximately two seconds per radiograph
  • Trained on expert‑annotated datasets​
  • Leveraging an analogy between X‑ray attenuation and Retinex-based optical shadow models
  • Yields artifact-corrected, high‑contrast panoramics without manual input.

Value proposition summary

  • Substantially improves anatomical visibility: de‑shadowing enhances Weber contrast in the mandibular canal region by up to ~50% where ghost jaw artifacts overlap, revealing canal borders and lesion margins that were previously masked.​
  • Demonstrates state‑of‑the‑art quantitative performance: artifact correction raises mandible and mandibular canal segmentation Dice scores (e.g., mandible Dice up to 0.9764 on a public dataset), outperforming multiple published methods even without enhancement.​
  • Reduces need for additional imaging: clearer depiction of nerve–tooth relationships and lesion extent can obviate CBCT in selected cases, decreasing radiation exposure, cost, and time.​
  •  Fully automated and scalable: high‑accuracy artifact segmentation (Dice up to ~0.96 for ghost jaw) yields downstream performance comparable to manual artifact labeling, eliminating labor‑intensive expert annotation at deployment.​
  •  Flexible platform: the framework can incorporate alternative de‑shadowing backbones, adapt to new artifact types, and generalize across public and private datasets, supporting broad clinical and commercial translation


Figure 1. A panoramic radiograph (top) overlaid with artifact segmentations (bottom). From left to right: the ghost image of the opposite jaw, the spinal overlay, the pharyngeal air-gap.

Potential applications

  • Clinical decision support in dentistry and oral & maxillofacial surgery – enabling clearer assessment of third molar proximity to the mandibular canal and TMJ morphology directly from panoramic X‑rays.​
  • Pre‑processing module for AI diagnostic tools (e.g., tooth, mandible, and mandibular canal segmentation, lesion detection) to improve accuracy and robustness across devices and institutions.​
  •  Integration into panoramic X‑ray systems or PACS as a real‑time image enhancement option for radiologists, surgeons, and general dentists.​

    Figure 2. The artifact removal process for panoramic X-rays. UNet++ is used to generate a mask of each artifact, which is then sent to a de-shadowing network. ShadowFormer enhances the image in artifact regions using the segmented masks. L1 differences are also shown.

Reference:
Dan et al (2025) Artifact Correction in Panoramic Radiographs using Deep De-shadowing,  ICCV Workshop

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