10 Questions and Answers About Dental Radiographic Interpretation

01.  What is the earliest radiographic sign of periapical disease of pulpal origin?

The earliest radiographic sign is widening of the periodontal ligament space around the apex of the tooth.

02 . What is the second most common radiographic sign of periapical disease of pulpal origin?

The second most common radiographic sign is loss of the lamina aura around the apex of the tooth.

03.    Describe the radiographic differences that allow one to distinguish among periapical abscess, granuloma, radicular (periapical) cyst, and an apical surgical scar.

One cannot distinguish among periapical abscess, granuloma, or radicular (periapical) cyst on radiographic grounds alone. All of these lesions are radiolucent with well-defined borders. Whereas an abscess may be expected to be less well corticated than a radicular cyst, this feature is not marked or constant enough to be of real utility. An apical surgical scar may be radiographically distinguishable from the other three lesions if there is radiographic evidence of surgery, such as a retrograde amalgam. Of course, a history should elicit the fact of surgery.

04.    How does the radiographic appearance of pulpal pathology that has extended to in volve the bone differ in primary posterior teeth from the picture commonly seen in perma nent posterior teeth?

In permanent teeth, widening of the periodontal ligament space is seen around the apex of the tooth. In primary teeth, by contrast, the infection presents as widening of the periodontal ligament space or an area of lucency in the furcation area.

05. Does any radiographic sign permit the diagnosis of a nonvital tooth?

It is frequently stated that tooth vitality cannot be determined by radiographs alone, but this is not so. The presence of a root canal filling in a tooth provides virtually conclusive proof of its nonvitality, as does the presence of a retrograde filling, usually amalgam.

06.  At times it may be difficult to distinguish between hypercementosis and condensing or sclerosing osteitis around the apex of a tooth. What radiographic feature permits a definitive diagnosis when one is confronted with this dilemma?

If hypercementosis is present, the periodontal ligament space is visible arou nd the added cementum; that is, the cementum is contained within and is surrounded by the periodontal ligament space. Condensing osteitis, by contrast, is situated outside the periodontal ligament space.

07.  What is the radiographic sign of an ankylosed tooth?

The radiographic sign of an ankylosed tooth is loss of the periodontal ligament space and lamina aura.

08.  What is the earliest radiographic sign of periodontal disease?

The earliest radiographic sign of periodontal disease is loss of density of the crestal cortex, which is best seen in the posterior regions. In the anterior part of the mouth, the alveolar crests lose their pointed appearance and become blunted. In the posterior areas, the alveolar crests usually meet the lamina aura at right angles. In the presence of periodontal disease, these angles become rounded.

09.    What is the earliest radiographic sign of furcation involvement due to periodontal disease? 

In periodontal disease, one may see the loss of a cortical plate, either the buccal or lingual plate, on an intraoral film. The plate may be lost so that the crest now occupies a position apical to the furcation. This appearance, however, does not permit a diagnosis of furcation involvement. Widening of the periodontal ligament space in the furcation area is the earliest radiographic sign of furcation involvement.

10 . What is the radiographic differential diagnosis of a radiolucency on the root of a peri odontally healthy tooth?

Internal resorption, external resorption, and superimposition are the most common causes. Note that the question refers to a periodontally healthy tooth. If bone loss has resulted in exposure of the root, caries and abrasion, among other potential possibilities, enter the picture.