A Comparative Study to Evaluate Bone Height Gain Following Transcrestal Sinus Floor Elevation Using Specially Designed Drills Versus the Conventional Osteotome Technique: a Randomized Controlled Clinical Trial.

Short implants (< 10 mm) are one of the options used to overcome low vertical bone height in the maxilla. However, short implants have faced many challenges as smaller implant surface; therefore less bone-to-implant contact after osseointegration with force distribution on a reduced surface after loading. This leads to more crestal bone resorption with more threads exposure decreasing the long term implant success Another treatment option is placing implants in specific anatomical areas, such as the pterygoid region or the zygoma .Many complications are reported as postoperative sinusitis, temporary paresthesia, epistaxis, facial, periorbital hematoma, orbital penetration and prosthetic difficulties due to the implants palatal emergence.

Vertical augmentation with bone grafts is another treatment option. However, it has many drawbacks as the unpredictable graft resorption, low bone to implant contact, higher possibility of wound dehiscence, as well as compromised implant position leading to undesirable prosthetic restorations.

To overcome the problems of the previously mentioned procedures, elevation of the sinus membrane techniques were proposed, it can be performed either through a lateral window , or via a crestal access depending on the remaining bone height (RBH). If the RBH is around 6-9 mm, the crestal approach is indicated. If the RBH is less than 5 mm, a lateral approach should be performed.

For the crestal approach, it could be performed by the conventional osteotome technique. However, it is a visually restrictive technique which may lead to sinus perforation as well as it can cause some complications as headache and paroxysmal positional vertigo (Saker e Ogle, 2005; Peñarrocha-Diago et al., 2008).

To overcome the disadvantages of the conventional osteotome technique, various kits have been developed for transcrestal sinus floor elevations using specially designed drills.