Preclinics of Conservative Dental Medicine · MU Sofia

17. Cavity preparation in incisal ridge fractures – resistance, retention and clinical decisions.

Explains how to classify incisal ridge fractures by the tissues involved, with a table linking the WHO/Andreasen and Ellis categories to findings and decisions. Covers examination, sealing exposed dentin, capping or partial pulpotomy for pulp exposure, and reattaching an intact fragment. Goes on to composite build-up steps, how a labial bevel gives retention and resistance, occlusal guidance, common mistakes and a closing list of key points.

Inside: 6 sections · 1 labelled picture · 1 table · 17 flashcards · 7 min

Topic 17 of 53 in the MU Sofia syllabus for Preclinics of Conservative Dental Medicine (Dental Medicine, Year 3). The free AceMed note covers it in 6 sections, about 903 words (7 min of reading), with 17 flashcards.

In this note

  1. Introduction
  2. Types of crown fracture
  3. Examination and clinical decisions
  4. Preparation for a composite build-up
  5. Main mistakes
  6. Key points

Introduction

Fractures of the incisal edge (incisal ridge), most often of the maxillary central incisors, are among the commonest dental injuries. The defect is a break of sound tooth, not caries, so the preparation is minimal and adhesive. The decisions: is the pulp involved, can the fragment be bonded back, and how is the new edge made retentive and strong enough to guide the bite?

Types of crown fracture

The WHO classification modified by Andreasen (used in the IADT guidelines) names the tissues involved; the older Ellis classification numbers the same groups (Ellis class IV is a tooth that has become non-vital after trauma). Enamel infraction (a crack without loss of tissue) and crown–root fracture are separate categories. Black's classes do not cover a defect limited to the incisal edge (the later-added Class VI does); when a proximal angle is lost, the restoration is a Class IV (topic 16).

Examination and clinical decisions

  • History: time since the injury (exposed dentin and pulp are contaminated over time) and where the fragment is; if it is missing and the lip is cut, radiograph the lip.
  • Sensibility tests (cold, electric) and a periapical radiograph (root development, root fracture, luxation). A negative test just after trauma does not prove necrosis: it is a baseline to repeat.

Decision by fracture type

  • Enamel: smooth the sharp edges with a fine diamond or discs, or add a small composite.
  • Enamel–dentin: open tubules let bacteria reach the pulp, so exposed dentin is sealed the same day, with glass ionomer or with adhesive and composite. Where the dentin over the pulp is thinner than about 0.5 mm (pink shine), a calcium hydroxide liner goes on that spot first, covered with glass ionomer.
  • Pulp exposure: keep the pulp vital, above all in an immature tooth, whose root must still grow. Direct pulp capping suits a pinpoint, fresh exposure. Partial pulpotomy (Cvek) removes about 2 mm of pulp under the exposure with a diamond bur at high speed under water spray; after haemostasis with saline the pulp is covered with a calcium silicate cement (MTA, Biodentine) or calcium hydroxide and sealed.
  • Refer for root canal treatment when the pulp is necrotic or irreversibly inflamed, when vital pulp therapy fails, or when a mature tooth needs a post.
  • Follow up with sensibility tests and radiographs, usually at 6–8 weeks and 1 year, more often after a pulp exposure.

Fragment reattachment

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