Sinus floor elevation is a commonly used technique to increase bone volume in the posterior maxilla prior to implant placement. This procedure was first developed by Tatum in 1977 [1], modified by Boyne and James in 1980 [2], and further modified over time. In this well-described technique, a bony window is created on the lateral wall of the sinus with a round burr, and the membrane elevated. Different materials have been used to fill the created space, such as autologous bone [3,4,5,6], bone substitutes alone [7], bone substitutes in combination with autologous bone [8], or no material [9].

Different methods of closing the antrostomy have also been used. The antrostomy can be left open, suturing the mucosa directly over the grafted material, or it can be covered with a resorbable [10] or non-resorbable membrane [11], or closed by repositioning the bony window [9, 12,13,14].

A systematic review and meta-analysis reported that the use of a resorbable membrane to cover the antrostomy resulted in better outcomes in terms of implant survival rate compared with no covering [10]. However, in another systematic review with meta-analysis, no difference in the bone formation was seen between the two methods [15].

A different method described in the literature is the repositioning of the removed bony plate onto the antrostomy. This technique was described by Lundgren et al. in 2004 [9]: a bevelled osteotomy with a thin reciprocating saw was created and the bony plate removed. After the sinus elevation, the bony plate was repositioned over the window.

In an experimental study in rabbits [16], a bilateral sinus augmentation was performed using a resorbable beta-tricalcium phosphate (β-TCP). The antrostomy was covered either with a collagen membrane or with a repositioned bony plate without any fixation. A faster and greater bone formation was reported in the repositioned bone plate sites.