Fractured tooth presents options for correction; classifications defined
Which part of the tooth is affected? Some fractures are limited to the enamel which require little or no therapy, others involve dentin which may or may not require endodontic care; and still other fractures expose enamel, dentin and pulp requiring endodontic care or extraction.
Worn teeth Chronic abrasion from self grooming, tennis balls or attrition from misaligned opposing teeth may result in injury to the tooth. This persistent low-grade trauma causes pulpal odontoblasts to produce tertiary dentin for repair and protection.
Probing the worn area with an explorer and radiographic examination will help evaluate the endodontic and periodontic involvement of worn teeth to see if therapy is indicated (Photo 3).
Fracture classificationClass 1 enamel (uncomplicated) fractures occur from trauma. The dentin or pulp is not exposed in class 1 fractures. Intraoral radiographs should be taken as a baseline and to check for apical fracture. The tooth should be re-radiographed six and 12 months later for evidence of periapical pathology.
Class 2 (uncomplicated, near pulpal exposure) fractures extend through enamel into dentin without pulpal penetration. In class 2 fractures, bacteria have an indirect pathway to the pulp through the dentinal tubules (Photo 5, p. 1S).
Class 2b (near pulp exposure) fracture extends below the gum line. Enamel and dentin are exposed sparing the pulp.
Treatment for class 2 fractures depends on the age of the animal (younger animals have less distance between dentin and pulp), and the degree of penetration into the dentin.
Indirect pulp capping covers exposed dentin with a layer of calcium hydroxide followed by glass ionomer cement. The tooth is restored with amalgam, acrylic composite or a cast crown.
Direct pulp capping covers the pulp (exposed with a round bur), with calcium hydroxide followed by restoration.
When exposure exists, endodontic therapy (vital pulpotomy, conventional or surgical root canal) should be performed or the tooth extracted (Photos 6, p. 1S, 7 and 8).
If the practitioner chooses to do nothing with a tooth affected with pulpal exposure, the exposed pulp will necrose eventually leading to periapical pathology and patient pain. Extraction or repair of the fractured tooth are the only sound treatment options. Leaving the tooth untreated to "watch and see what happens" is unjustifiable.
Class 3b (complicated crown and root) fractures have enamel, dentin and pulp chamber exposure with extension below the gum line.
Slab fractures occur when a slice of the crown separates from the buccal or lingual/palatal surface of a tooth. Once the fracture segment is removed and discarded, pulpal exposure may be visualized. The fracture often extends subgingivally. Slab fractures commonly occur on the buccal surface of the maxillary fourth premolar in a dog that has been chewing bones or cow hooves.
Treatment options include root canal therapy with gingival surgery to eliminate the pocket to save the tooth or extraction (Figures 9, 10).
Class 4 (root) fractures involve dentin, cementum and pulp. Root fractures are classified by the anatomic location of the fracture (coronal, middle or apical third). Coronal root fractures often present with a highly mobile crown (Figure 11).
Age of the fracture will influence the endodontic treatment. In acute fractures, the pulp appears pink or red at the fracture surface. The pulp of a long-standing fracture will appear brown or black. Shortly after pulpal exposure, inflammation occurs less than 2 millimeters from the exposure site. Healthy pulpal tissue can be found several millimeters deeper within the pulp, which may respond to vital conservative pulp procedures.
Partial coronal pulpectomy (vital pulpotomy) is an endodontic procedure in which the vitality of the pulp is preserved and tooth maturation is allowed to continue. The procedure involves removal of a portion of the pulp in the chamber of the crown, leaving the pulp in the root undisturbed. Partial coronal pulpectomy can be performed if the fracture is less than 48 hours old in the patient older than 9 months, or less than 2 weeks in the patient younger than 9 months.
Consider patient's ageAge of the patient is also important when choosing therapy options. Teeth of patients younger than 9 months have open apices. Conventional root canal therapy is not performed on these animals because sealing the apex cannot be assured. Treatment options include partial coronal pulpectomy (vital pulpotomy) to promote apexogenesis or an apexification procedure based on the pulp health. Patients older than 9 months with pulpal exposure should be treated with conventional root canal therapy.