Pathology radiology most pertinent dianostic

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Sep 01, 2004


Jan Bellows DVM, dipl. AVDC, dipl. ABVP
Endodontics is the branch of dentistry dealing with the diagnosis and treatment of pulpal and periapical disease. When confronted with a traumatized tooth, the veterinarian must be able to recommend extraction, root canal therapy or vital pulp care. Intraoral radiographs offer the most pertinent piece of diagnostic information to illustrate what is going on below the gum line.


Image 1 shows enhanced periodontal ligament at the root's apex with digital radiography.
The pulp is contained within the root chamber and canal portions of the tooth. The pulp system is divided into two parts: the pulp chamber located in the crown, and the root-canal system emerging from the floor of the pulp chamber extending though the root(s) into the periodontal ligament in the periapical area.


Image 2 shows normal apical anatomy in a dog's mandibular canine showing consistent lamina dura.
Radiographic anatomy A dental X-ray shows two-dimensions of the tooth and surrounding structures that are three-dimensional objects. Often multiple radiographs of a particular area are exposed and evaluated to make decisions. Digital dental radiography provides instant images without processing and allows the clinician to enhance images (see Image 1).


Image 3 shows periapical disease of a cat's maxillary canine, displaying loss of the apical lamina dura and periodontal ligament space.
In a healthy tooth, the periodontal ligament space is surrounded by a compact layer of bone called the lamina dura. As pulpal infection spreads to the periapical tissues, bone is resorbed, the periodontal ligament space appears wider and/or the lamina dura loses its continuity (Images 2-3).


Image 4 shows wide pulp chamber and open apex.
Pulp width decreases with age as pulpal odontoblasts produce dentin, which lines the pulp chamber. In the young dog or cat, less than 9 months old, the pulp chamber will be wide occupying a majority of the tooth. The apex will also be open (Image 4).


Image 5 shows thin pulp chambers in the maxillary central incisors of an 8-year-old dog.
In the older dog or cat, the pulp chamber will be very thin and barely radiographically observable (Image 5, p. 18S).


Image 6 notes the root fracture in the mobile maxillary incisor.
Radiograph interpretation Early in the disease process radiographs might appear normal even with pulpal necrosis because at least 10-percent bone loss must be present in an area to radiographically notice periapical disease.


Image 7A shows pulpal exposure of a premolar tooth caused by tennis ball chewing.
The radiograph of the endodontically effected tooth is examined in an orderly and consistent manner. First, the crown and then the root(s) are inspected, followed by the root-canal system, the lamina dura and periapical area.