This paper describing Tatum’s “trap door” method of increasing the absolute bone height in the lateral maxilla.

Technique involves surgically creating a top hinge door in the lateral sinus wall, turning the door inward and upward together with the intact sinus mucosa, and filling the newly created space with bone graft.

Indications:

• • Insufficient bone height (< 10 mm) is available for dental implants or totally edentulous maxillae with insufficient bone height.

Contraindications:

A-  Absolute:

• • Previous sinus surgery such as Caldwell Luc procedure
  • Maxillary sinus diseases such as tumors or chronic polypous sinusitis
  • Strong allergic conditions.

B- Relative:

• • Presence of Underwood’s septa or severe sinus floor convolutions
  • Contours of dental roots in the floor of the sinus
  • Extremely narrow sinus.

The gold standard graft material is autogenous (iliac crest, tibia head, chin, coronoid process, and/or lateral buccal cortical bone plate of the mandible) bone.

Implantations can be performed at sinus lifting (one-stage) or at a later date (two-stage).

1- One stage procedure:

Must have good quality and quantity of bone to provide good primary stability of the implant.

2- Two-stage:

When < 4 – 5 mm vertical bone height is available, ≥ 4 months after sinus lifting with autogenous bone.

Complications:

• Perforation of the Schneiderian membrane (most common)
• Infection
• Possible loss of the graft into the sinus, and subsequent sinusitis.