Extraction chapter
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OroNasal or OroAntral Fistula


Large, chronic, functional oral nasal fistula at site of 104
Large, chronic, functional oral nasal fistula at site of 104



This complication can occur in any location from the upper canines, caudally. Oro-nasal refers to a communication between the oral and nasal cavity - most commonly at the site of the maxillary canine. Oro-antral refers to a communication between the oral cavity and the maxillary sinus - most common following upper premolar 4 (carnassial) extraction. They are most common where the bone plates are thinnest - either naturally or after periodontal or metabolic disease.

Correct attention at the time of extraction can limit the need for complex flap surgery later.

Debride socket gently with 0.05% chlorhexidine gluconate (CHX Solution™: St Jon VRx Products) and fill with alloplastic graft material if a solid floor is present. This may require a mesh type product (BioSyst™) followed by BoneGlass (Consil™). Suture tissues should be sutured without tension. Treat with suitable antibiotics.

Review after four to six weeks to identify the need for flap surgery. This timeframe will allow for wound contraction.

The main reasons for dehiscence of flaps are:

  • Chronic osteitis at site from local infection
  • Tension on sutures
  • Suture lines unsupported and located over a void.

Expect 20% contraction of soft tissue during healing. Tension on flaps is usually due to poor flap design. To prevent this, ensure that the releasing incisions are made off the target tooth, preferably at the line angle of the teeth rostrally and caudally, and that the flap is sufficiently undermined before suturing.

Many ONF's stay open due to the pressure differential between the nasal and oral cavities. After six weeks, if the ONF is large enough to cause chronic rhinitis and sneezing, closure by flap surgery is indicated.




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