Root Fracture of Tooth

Root fracture of a tooth is a break through the root involving dentine, cementum and pulp, usually horizontal or oblique, with a coronal fragment that may be mobile. It makes up about 0.5 to 7% of permanent tooth injuries.

It is usually seen in mature teeth in patients of 11 to 20 years, and in the maxillary central incisors. Fractures are classified by location as apical, middle and coronal (cervical) thirds, and the level decides the outcome.

Pathophysiology. A horizontal impact transmits stress to the root, which fractures at its weakest point. The apical fragment usually keeps its pulp supply, and the coronal fragment may lose it, so pulp necrosis of the coronal segment occurs in about 20 to 44%.

Healing happens through four patterns: hard tissue union, connective tissue union, bone and connective tissue union, and non-union with granulation tissue between fragments, usually with necrotic coronal pulp.

A tooth that is mobile and may be displaced, slightly extruded, or lingually tilted, with tenderness on biting, bleeding from the sulcus, and a dull percussion note. The more coronal the fracture, the greater the mobility. A fracture at the apical third may have little mobility.

The tooth may discolour grey or pink in the weeks after. Check other tooth and alveolar injuries and tetanus status.

Head injury, airway concern, other fractures and contamination need urgent assessment.

• Periapical radiographs at three angles (a periapical view at the usual angle and views angled 15 to 20 degrees mesially and distally, with an occlusal view), and an occlusal view, since a horizontal fracture may not show on a single view.
• Cone beam CT for the level, the direction and for oblique or cervical fractures, and a vertical component.
• Pulp sensibility tests at baseline (may be negative from transient damage) and at follow up.
• Mobility and percussion, and measurement of displacement.
• Tetanus status.

Differential diagnosis.

• Crown root fracture
• Luxation without fracture
• Vertical root fracture
• Alveolar fracture
• Pre-existing root resorption
• Normal anatomical lines on a radiograph (nasal floor, mental foramen, canal)

• Reposition the coronal fragment as accurately as possible under local anaesthesia, check by radiograph, and stabilise with a flexible splint: 4 weeks for apical and middle third fractures, and up to 4 months for coronal third fractures.
• Do not start root canal treatment at once. Monitor the pulp for 3 to 6 months. If the coronal pulp becomes necrotic, treat the coronal segment only, with calcium hydroxide dressing and a root filling to the fracture line, or use calcium silicate apical plug in immature teeth. The apical segment is left alone.
• Coronal third fractures: when splinting fails or the fracture is near the gingival margin, extract the coronal fragment and extrude the apical segment orthodontically or surgically, or remove the tooth and replace it.
• Apical third fractures often heal and need only monitoring.
• Antibiotics are not routinely needed. For contaminated wounds or other injuries: amoxicillin 500 mg orally three times daily for 5 to 7 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. Children under 12: 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.
• Chlorhexidine 0.12% mouthwash 10 mL twice daily for 1 week, soft diet, and no contact sport.
• 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.

Monitoring. Review at 4 weeks (splint removal), 6 to 8 weeks, 4 months, 6 months, 1 year, and then yearly for 5 years, with radiographs, percussion, mobility and sensibility tests.

Referral and escalation. Refer to a dental trauma service or endodontist. Urgent referral for coronal third fractures, multiple injuries, or infection.