Radiographic Diagnosis Of Periodontal Diseases

Radiographic Diagnosis Of Periodontal Diseases

Write short note on various radiographs in diagnosis of periodontal diseases.
Answer.

Radiographs used in Diagnosis of Periodontal Diseases

Conventional Radiographic Methods

• • Intraoral periapical radiograph
  • Bitewing radiograph
  • Orthopantomograph
  • Xeroradiography

Advanced Radiographic Techniques

• Digital radiography
• Xeroradiography
• CADIA
• CT scan
• Subtraction radiography and computer-assisted subtraction
• Absorptiometry
• Photodensitometric analysis technique
• Nuclear medicine bone scan

Conventional Radiographic Methods

Intraoral Periapical Radiograph

They are helpful in assessing the periodontal status and for detecting the periapical infection.

Bitewing Radiographs

They show both maxillary and mandibular teeth along with interdental alveolar bone. So in periodontal diagnosis, they provide us vital information regarding presence of local irritating factors such as calculus.

Orthopantomograph

They have the tendency to underestimate minor bone changes. Major disadvantages are magnification, unsharpen and distortion. Clarity of panoramic image is obtained from digital machines is superior to conventional machines.

Xeroradiography

It does not involve wet chemical processing or the use of a dark room. Instead of X-ray film, xeroradiography uses a uniformly charged selenium plate held in a light tight cassette. Exposure to X-ray and adequate processing produces a real image on opaque paper, which is viewed by reflected light. It is less expensive.

Advanced Radiographic Techniques

These techniques are developed to enhance the ability to see small changes overtime in the bone. The advanced radiographic techniques are:

• Digital Radiography (RVG):
  • Digital radiography allows the use of computerized images, which can be stored, manipulated, and corrected for underexposures and overexposures.
  • Digital radiography may yield image properties almost equal to conventional radiographs, but through digital storage and processing, diagnostic information can be enhanced.
  • Moreover, there is a one-third to half reduction in radiation dose obtained with digital radiographs compared with conventional radiographs.
  • Digital intraoral radiography is in a state of rapid development. Sensors as well as computer hardware and software, are continually modified and improved.
  • Because of the clear advantage of real or almost-real images that can be improved and the important educational component of online images presented to the patient, it is expected that digital radiography will soon replace conventional radiography in modern daily practice.
• Computer-assisted densitometric image analysis (CADIA)
  • In CADIA, a video camera measures the light transmitted through a radiograph, and the signals from the camera are converted into gray-scale images. The camera is interfaced with an image processor and a computer that allow the storage and mathematic manipulation of the images.
  • CADIA appears to offer an objective method for following alveolar bone density changes quantitatively over time. Also, compared with digital subtraction analysis.
  • CADIA has shown a higher sensitivity and a high degree of reproducibility and accuracy. This technique has also been applied to longitudinal clinical studies.
• Computerized tomography (CT) scan
  • Unlike conventional radiography, which is a two dimensional representation of a three-dimensional object. Computed tomography gives an exact picture of the bone levels in coronal, axial and sagittal plane by which all the osseous defects can be visualized accurately.
• Subtraction radiography: In this procedure, two radiographs are taken and the changes are noted depending on the grey levels.
  • Digital subtraction radiography
    • Digitalization is done before subtraction, i.e. serial radiographs are converted to digital images.
    • Digital images are superimposed and are used on a video screen. Light areas indicate bone gain and dark areas indicate bone loss.
• Absorptiometry: A non-radiographic method to analyze the periodontal bone mass changes. It is based on the absorption by bone of a low energy gamma beam, originating from a radioactive source of l25-I. This method has shown to measure bone changes with a high degree of accuracy and precision.
• Photo-densitometric analysis technique: A beam of light is passed onto the radiographic film and the image is shown on an aluminum scale and then it transforms the density readings into millimeter of aluminum equivalents. It is mainly developed to evaluate bone resorption especially in furcation areas. This technique mainly enables the clinician to detect the variations in the bone density that cannot be detected by visual inspection.
• Nuclear medicine bone scan
• It involves the detection of changes in bone metabolism, so it can detect the earliest stage of bone loss.
• A bone seeking radiopharmaceutical diphosphonate compound is injected intravenously and after the waiting period the uptake by the bone is measured by the semiconductor probe radiation detector.
• This technique is of importance because it detects the bone changes before structural alterations occur.