Endodontics · patient case with 2 questions
Trauma to the maxillary central incisors in a young adult
Patient: Male, 21 years old
Chief Complaint: “I hit my mouth on the edge of the pool and broke my front teeth.”
Background: Injury occurred four hours ago. No loss of consciousness, no nausea. Tetanus status current. Healthy, no medications.
Vital Signs: BP 126/78 mmHg · HR 88 bpm · T 98.4°F
Findings: Tooth #8: fracture through ENAMEL, DENTINE and with a visible PULP EXPOSURE of approximately 1 mm, bleeding, and exquisitely sensitive. Tooth #9: fracture through enamel and dentine only, NO pulp exposure. Separately, #8 is also INTRUDED approximately 3 mm into its socket. Radiographs show no root fracture and mature apices on both teeth.
Question 1
How is the fracture of tooth #8 classified?
Show answer and explanation
Correct answer: A. Complicated crown fracture
- A. CORRECT. In the current IADT and WHO nomenclature, a crown fracture is COMPLICATED when the PULP IS EXPOSED and UNCOMPLICATED when it is not. Tooth #8 has a visible, bleeding pulp exposure, so it is a COMPLICATED CROWN FRACTURE. The word 'complicated' refers to pulpal involvement and nothing else — not to the size of the fragment, not to how difficult the restoration will be.
- B. A root fracture is confined to the root and is visible radiographically as a lucent line across it. The radiographs explicitly exclude this.
- C. Uncomplicated describes tooth #9 — enamel and dentine with no exposure. That is what makes the pair in this case a useful teaching contrast.
- D. A crown-root fracture extends from the crown BELOW the cementoenamel junction into the root, usually obliquely, and typically involves the palatal aspect. Neither tooth is described this way.
Note: What this item adds is the CURRENT terminology, which is what recent examinations use. Map the two: Ellis I = enamel only, an uncomplicated crown fracture; Ellis II = enamel and dentine, still uncomplicated; Ellis III = pulp exposed, a COMPLICATED crown fracture; Ellis IV = the tooth is non-vital. Management of #8 here: with a mature apex, a small exposure and treatment within 24 hours, PARTIAL PULPOTOMY (Cvek) with calcium hydroxide or MTA has an excellent prognosis and preserves vitality — root canal treatment is not the automatic answer.
Question 2
Tooth #8 is to be repositioned by ORTHODONTIC EXTRUSION. Which factor most needs to be taken into account?
Show answer and explanation
Correct answer: B. The crown-to-root ratio
- A. The curve of Spee is an arch-form consideration in comprehensive orthodontics, not the governing concern in extruding a single traumatised incisor.
- B. CORRECT. Extrusion moves the tooth coronally, and the bone and attachment follow it only partially — so the clinical crown lengthens while the ROOT LENGTH SUPPORTED BY BONE shortens. Every millimetre of extrusion therefore worsens the CROWN-TO-ROOT RATIO, and in a traumatised tooth already at risk of external resorption from the intrusion injury, that margin matters. Assess the starting ratio, extrude slowly with light continuous force, and accept that a tooth with a short or resorbing root may not tolerate the movement.
- C. Overbite will change as the incisor is extruded, and the occlusion must be checked — but it is a consequence to manage, not the limiting factor on whether the movement is feasible.
- D. Overjet is the horizontal overlap of the incisors. Extrusion is a vertical movement and does not principally alter it.
Note: Two further points on the intrusion itself. Management depends on APEX MATURITY: an immature apex intruded less than 7 mm may be left to re-erupt spontaneously; a MATURE apex, as here, needs orthodontic or surgical repositioning, started early. And intrusion carries the WORST prognosis of all luxation injuries — pulp necrosis is near-universal in mature teeth, so plan endodontic treatment within two to three weeks, and watch for replacement and inflammatory resorption at every review.