Crown Fracture of Tooth

Crown fracture of a tooth is a break of enamel, or enamel and dentine, with or without exposure of the pulp, and without involvement of the root. It is the commonest dental trauma injury, making up about 26 to 76% of permanent tooth injuries.

The maxillary central incisor is the usual tooth, in children aged 8 to 12 years and young adults. Severity ranges from enamel cracks to fractures exposing the pulp.

Pathophysiology. Impact force exceeds the strength of the enamel and dentine and the crown fractures, leaving exposed dentinal tubules that allow bacteria to reach the pulp within hours to days.

When the pulp is exposed, bacteria invade and cause inflammation and necrosis. In immature teeth, the pulp has a good capacity to heal if treated early.

A missing or chipped piece of crown, sharp edges, pain on cold air or hot and cold food, bleeding from an exposed pulp, and sometimes a tooth with associated luxation. The fracture types are:

• Enamel infraction (crack, no loss of substance) and enamel fracture.
• Enamel and dentine fracture without pulp exposure.
• Enamel and dentine fracture with pulp exposure (complicated).

Check the lips, tongue and cheeks for embedded fragments, other tooth injuries, and tetanus status.

Pulp exposure with severe pain, associated luxation, soft tissue wounds with embedded fragments, and head injury need urgent assessment.

• Clinical examination of the fracture, depth, pulp exposure (a pink or bleeding spot) and size, with transillumination for cracks.
• Percussion, mobility and pulp sensibility tests at baseline and at follow up.
• Periapical and occlusal radiographs to exclude root fracture, luxation and the fragment in the soft tissue. Soft tissue radiograph of the lip when fragments are missing.
• Assess root development (open or closed apex).
• Tetanus status.

Differential diagnosis.

• Crown root fracture
• Root fracture
• Luxation with crown fracture
• Enamel hypoplasia or erosion
• Caries with crown breakdown
• Non-carious cervical lesion
• Tooth wear or attrition

• Keep the fragment in saline or milk, since reattachment gives good aesthetics and function.
• Enamel infraction: seal or polish. Enamel fracture: smooth sharp edges and restore with composite if needed.
• Enamel dentine fracture without exposure: cover the dentine at once with glass ionomer cement or restore with composite, or reattach the fragment with bonding. Early sealing reduces pulp injury.
• Complicated fracture (pulp exposed):
  • Immature teeth: vital pulp therapy is preferred, with partial pulpotomy (removal of 2 to 3 mm of inflamed pulp) or pulp capping using a calcium silicate cement, followed by a sealed restoration. Success is about 90% or more with a good seal.
  • Mature teeth: pulp capping, partial pulpotomy or full pulpotomy for recent small exposure, and root canal treatment if the pulp is necrotic or irreversibly inflamed.
• Restore the crown definitively after healing, with a composite or a veneer. Aesthetic restoration needs bleaching of discolouration later.
• Antibiotics are not required for isolated crown fracture. For soft tissue wounds with contamination, amoxicillin 500 mg orally three times daily for 5 days (reduce to 500 mg every 12 hours at eGFR 10 to 30), or doxycycline 100 mg orally twice daily for 7 days in patients aged 12 years and over, and children under 12 take amoxicillin 125 mg three times daily at 1 to 11 months, 250 mg at 1 to 4 years and 500 mg at 5 to 11 years.
• Tetanus toxoid 0.5 mL intramuscularly if vaccination is incomplete or the last dose was over 10 years ago, with tetanus immunoglobulin 250 IU intramuscularly (500 IU after 24 hours or heavy contamination) for contaminated wounds when status is unknown or incomplete.
• Analgesia: paracetamol 1 g every 6 hours (maximum 4 g daily) with ibuprofen 400 mg every 8 hours with food. Children use paracetamol 15 mg/kg every 4 to 6 hours (maximum 75 mg/kg daily) and ibuprofen 5 to 10 mg/kg every 6 to 8 hours. Soft diet and no contact sport until restored.

Monitoring. Review at 6 to 8 weeks, 3 months, 6 months, 1 year, and yearly for 5 years, with percussion, sensibility tests and radiographs. Pulp necrosis, canal obliteration and root resorption can appear late.

Referral and escalation. Refer to a dentist or paediatric dentist the same day for pulp exposure. Refer to endodontics for complex pulp therapy. Urgent referral for associated luxation, alveolar fracture or head injury.