Wilhelm Roentgen, Professor of Physics in Wurzburg, Bavaria, discovered X-rays in 1895—accidentally—while testing whether cathode rays could pass through glass. Different radiographic techniques are used in dentistry. The most commonly used techniques are:
○ 1. Intraoral views
○ 2. Occlusal views
○ 3. Panoramic views
○ 4. View of the temporomandibular joints
○ 5. View of the facial bones.
❖ INTRAORAL RADIOGRAPHS:
- Periapical projections, which show the entire length of the tooth and the surrounding bone
- Bitewing projections, which show only the crowns of teeth and the adjacent alveolar crests
- Occlusal projections, which show an area of teeth and bone larger than periapical images.
Diagnostic Objectives of Periapical Radiography
• Asses extent of dental caries
• Detect the presence and assess the extent of periapical inflammation
• Evaluate consequences of traumatic injuries to the teeth and alveolar bone
• Assess periodontal bone loss
• Evaluate root morphology
• Assess implant osseointegration and peri-implant bone loss
• Evaluate unerupted and impacted teeth
• Evaluate external and internal root resorption
• Assess pulp morphology
• Determine the length of endodontic instrumentation during treatment
❖ BITEWING RADIOGRAPH:
➢ Bitewing (also called interproximal) radiographs include the crowns of the maxillary and mandibular teeth and the alveolar crest on the same receptor
➢ Diagnostic Objectives:
• Detect early interproximal caries
• Detect secondary caries below restorations
• Assess loss of the interdental and furcation bone.
❖ OCCLUSAL RADIOGRAPH:
➢ An occlusal radiograph displays a relatively large segment of a dental arch.
➢ To make an occlusal radiograph, a large receptor (7.7 cm × 5.8 cm [3 inches × 2.3 inches]) is inserted between the occlusal surfaces of the teeth. Occlusal receptors are made of film or storage phosphor plates.
➢ It may include the palate or floor of the mouth and a reasonable extent of the contiguous lateral structures.
➢ When the patients are unable to open wide enough for periapical images, and for visualizing clefts.
❖ PANORAMIC RADIOGRAPH:
Panoramic radiography (also called pantomography) results in a wide, curved image layer depicting the maxillary and mandibular dental arches and their supporting structures.
They can be used in locating any localized abnormality or the examination of tuberosities, extensive implant procedures that may involve the entire jaw, both jaws, large donor graft sites, or sinus augmentation.
Panoramic radiography has less resolution than periapical radiography.
❖ CEPHALOMETRIC IMAGING:
cross-sectional images can be obtained which are useful to assess the position and inclination of teeth. Different types of cephalometric imaging are:
- lateral cephalometric;
- Submentovertex projection;
- Waters view;
- reverse Towne view.
❖ COMPUTED TOMOGRAPHY (CT):
➢ Computed tomography has been widely advocated for implant site assessment especially in the posterior regions of the jaws and for complex cases.
➢ These images are usually acquired perpendicular to the long axis of the body.
➢ The density of structures within the image is absolute and quantitative and can be used to differentiate tissues in the region and characterize the bone quality
❖ CONE BEAM COMPUTED TOMOGRAPHY (CBCT):
➢ CBCT is the most significant technologic advance in maxillofacial imaging since the introduction of panoramic radiography.
➢ The operation of maxillofacial CBCT devices is technically simple and similar, in many respects, to digital panoramic radiography.
➢ The spatial resolution—and therefore detail of a CBCT image—is determined by the dimensions of individual voxels produced in formatting the volumetric data set
- Temporomandibular Joint Imaging
- Implant imaging
❖ MAGNETIC RESONANCE IMAGING (MRI):
- Magnetic resonance imaging uses electromagnetic radiation of significantly lower energies than x-rays and at energies that are non-ionizing.
- Because of its excellent soft-tissue contrast resolution, MR imaging is useful in evaluating soft tissue conditions.
- Applications of MRI in dentistry include:
- Evaluate salivary gland diseases, including cysts and neoplasms, infections, and obstructions, TMJ articular disk
- Evaluate vascular lesions in the orofacial region
Proper modality of radiographic interpretation, good technical skill in taking radiographs, thorough radiographic study, proper interpretation help to reach a perfect diagnosis and optimum treatment.