The maxillary 4th premolar (the maxillary carnassial tooth) is one of the most, if not the most, commonly fractured teeth.
This tooth shears edible pieces of food for further degradation by the molar teeth. It lies more buccal (lateral) to its occlusal counterpart, the mandibular 1st molar. When occlusal force is applied to hard objects trapped between these teeth, it creates significant shearing force to the mesial cusp tip of the maxillary 4th premolar. In some cases, the result is a mesial cusp tip fracture in combination with a buccal wall fracture of the tooth, clinically referred to as a "slab fracture."
Fracture Types
The maxillary 4th premolar has 3 roots that are divergent from coronal to apical with respect to one another. One of the most important aspects of fracture of this tooth is whether or not the pulp canal has been exposed. If the pulp is involved, the current terminology refers to this as a complicated crown fracture; if the pulp is not involved, then it is uncomplicated. Fractures of the crown that extend below the gingival margin are classified as crown-root fractures.
Radiography
If the outer enamel is fractured away, exposing the underlying dentin and no pulp involvement is noted by careful exploration, the affected tooth should be radiographed (see Dental Radiography of the Maxillary 4th Premolar, Simplified, January 2007, available at cliniciansbrief.com) to view the root/periapical anatomy and evaluate periodontal health. If there is any question about root integrity, the periapical bone, or periodontal status, the contralateral tooth can be radiographed for comparison.
Techniques
Odontoplasty
If the crown is fractured but the pulp is not exposed and the tooth is otherwise healthy, smoothing of any irregular enamel (odontoplasty) plus the application of a dentin bonding agent should help seal any exposed dentinal tubules, which helps protect underlying pulp tissue and reduces or eliminates sensitivity. Periodic follow-up radiographs will help evaluate any pulpal pathology.
Extraction
If the tooth is not periodontally sound, extraction is indicated. Other indications include:
- Retained deciduous teeth or retained roots of teeth
- Crowded teeth that may cause periodontal or orthodontic problems
- Supernumerary teeth contributing to dental disease
- Unerupted & maloccluded teeth
- Unsalvageable & nonvital teeth
- Teeth with large carious lesions or gross decay
- Abnormally developed teeth (root or crown dilaceration)
- Teeth experiencing internal or external crown or root resorption
- Teeth within neoplastic masses (removed when mass is excised)
- Diseased teeth in the line of a fracture that do not contribute to function or interfere with fracture healing.
Extraction may also be an economic alternative to other dental procedures when the client desires definitive treatment.1-4 Contraindications for extraction include poor general health of the patient (anesthesia not possible), patients with coagulation disorders or those on medications that might affect coagulation, and teeth in an area previously treated with radiation therapy or chemotherapy.1
Other Techniques
If there is pulp involvement (complicated crown fracture with or without root involvement) and the tooth is otherwise periodontally sound, then it should either be extracted or have endodontic therapy (in most cases, complete pulpectomy and obturation, which is standard root canal therapy).
The following steps address surgical extraction of a fractured maxillary left 4th premolar tooth (#208).
STEP BY STEP SURGICAL EXTRACTION: FRACTURED MAXILLARY 4TH PREMOLAR
The patient is anesthetized, dental radiographs taken, tooth assessed, and multimodal pain management, including dental nerve block, instituted.