Sinus Floor Augmentation and Simultaneous Implant Placement, Part I: The 1-Stage Approach

Implant placement in the posterior maxilla is frequently complicated and challenging because of the poor quality and inadequate height of bone. One of the most important anatomic structures to be considered during dental implant placement in the posterior maxilla is the maxillary sinus.

After tooth loss, the periosteum of the maxillary sinus can exhibit increased osteoclastic activity, which can cause bone resorption.1 Bone resorption can result in bone height deficiency in the posterior maxilla, which may prevent the placement of implant in that area. In such cases, sinus floor elevation is a treatment option that can help resolve the problem. The procedures for sinus elevation for dental implant placement are as follows:

• The 2-stage lateral approach: The first stage entails sinus elevation and augmentation, and the second stage entails implant placement 6 to 18 months later. This is indicated when the bone height on the sinus floor is less than 4 mm.2 

• The 1-stage lateral approach: The dental implant is placed simultaneously with sinus elevation and augmentation. This is indicated when the bone height is 4 to 6 mm.3 

• The osteotome technique or crestal approach: Implants are placed at the same time that the sinus floor is locally augmented.3,4 This is indicated when the bone height is more than 5 to 6 mm.

Sinus floor augmentation with autogenous bone grafting for implant placement was first described by Boyne and James.5 Summers3,4 was the first to suggest the crestal approach osteotomy technique for sinus floor elevation. Summers suggested placing autogenous bone graft mixed with human demineralized freeze-dried bone and a small amount of reabsorbable hydroxylapatite to augment the sinus floor by the osteotome technique. The aim of this paper is to report a case with a bone height of approximately 5 mm in the extracted site of #3, where a nonsubmerged implant was placed simultaneously with the osteotome sinus floor augmentation technique, as well as the results at 12-month follow-up.

A 56-year-old man was referred to the author's clinic for periodontal treatment in July 2001. After clinical (Figure 1) and radiographic (Figure 2) examination, a diagnosis of generalized moderate to advanced periodontitis for #2, #3, #14, and #31 was made. The patient's medical history was unremarkable; therefore, full mouth periodontal flap surgery was performed for elimination of the periodontal pockets.

Tooth #3 was extracted during periodontal surgery because of extensive bone loss and mobility. Postoperative healing was uneventful, and the patient was seen every 3 to 4 months for recall and scaling. In August 2002, the patient requested replacement of #3 by implantation.

A periapical radiograph was taken, and approximately 5 mm of bone height was noticed on the extracted site of #3 (Figure 2A and B). The decision was made to place a 10-mm-long nonsubmerged implant at the site while simultaneously performing a modified osteotome technique to augment the sinus floor.

After local anesthesia was administered to the patient, an intrasulcular incision was made on the buccal and palatal of #2 and #4 with a midcrestal incision on the edentulous area of #3. A full-thickness flap was reflected, and a round bur (#6) was used to penetrate the cortical bone and initiate the implant osteotomy site. A 2.2-mm-diameter pilot drill followed by 2.8- and 3.4-mm drills were then used to widen the osteotomy site to a length of 4 mm. Then a mixture of previously prepared autogenous bone chips and Biogran synthetic bone graft (3i, Palm Beach Garden, Fla) was applied into the osteotomy site by a concave-tipped, 2.8- to 2.8-mm osteotome. The grafting material and the osteotome were advanced with gentle malleting to break the sinus floor and push up the schneiderian membrane without damaging the membrane (Figure 1B).

This was repeated 3 to 4 times followed by placement of a 10-mm-long and 4.1-mm-diameter nonsubmerged screw-type implant. The surgical site was closed, and an immediate postsurgical radiograph was taken (Figure 2C). Postsurgical medication, including amoxicillin, 500 mg every 6 hours for 7 days, and analgesic with 0.02% chlorhexidine-gluconate mouthwash twice a day, was prescribed.

Ten days later the sutures were removed and the healing was uneventful. The patient was seen again 2, 4, 6, 8, and 12 months later. At 8 months postoperatively, an radiograph was taken (Figure 2D), and the patient was referred to a prosthodontist for crown restoration of the implant. As is shown in the radiographs taken 8 and 12 months postoperatively (ie, 6 months after loading), a significant amount of new bone was regenerated on the sinus floor and covered the entire length of the implant (Figure 2D and E).

Implant placement in the atrophied maxillary posterior ridge with inadequate height of bone to restore masticatory function has always been difficult and challenging for clinicians. In the past few years, much attention and effort have been paid to developing a surgical technique to overcome this problem. The surgical technique currently used to augment the sinus floor to place the implant is either the lateral window opening or the osteotome technique.

The lateral window opening is a more invasive and extensive procedure compared with the osteotome technique. As a result, more complications can be expected in the former technique. In a recent study, Schwartz-Arad et al6 reported 44% membrane perforation in 81 sinuses operated on by the lateral window opening technique. They also found that surgical complications did not significantly influence the implant survival.

On the other hand, the osteotome technique seems to be easier to perform, with the possibility of fewer surgical complications.7–9 However, there is always a chance of membrane perforation due to lack of visibility, and as a result, more caution and experience are required to perform this procedure. Yet, not many reports exist of complication in the osteotome technique. Our clinical observations also showed no complications or patient discomfort.

The 12-month follow-up of this case showed that the entire 10-mm length of the implant was covered by healthy bone (almost 5 to 6 mm of new bone). Furthermore, with regard to our findings and other reports, it seems that the sinus floor augmentation can be achieved by the simpler osteotome technique, with a shorter operating time and fewer surgical complications.