Abstract
This technical note describes a new surgical technique for a palatal approach to the maxillary sinus for a vertical augmentation prior to dental implant placement. In 12 fully or partially edentulous patients (seven women, five men), 16 palatal sinus elevations were performed. After elevation of palatal full-thickness flap a rectangular access window was cut with a piezosurgical device. The raised sinus cavity was augmented with a synthetic nano-structured hydroxyapatite-based graft material. No harm occurred to the greater palatine artery or the sinus membrane. The vestibular and periimplant gingiva were preserved and there was no disharmonious soft tissue distortion or massive scar formation. Swelling and bleeding were minimal. Primary stability was achieved for all but one implant. This technique may be an alternative to other sinus augmentation approaches in cases where enough transversal width of the posterior alveolar crest is available.
Maxillary sinus floor augmentation is an integral part of modern implantology. The most widely practised method is the classical lateral antrostomy approach with a trap-door design and its modifications . The trap-door is rotated medially to push the schneiderian membrane cranially and create a chamber with a cortical ceiling. The major variations of the original lateral antrostomy technique can be classified as hinge osteotomy, elevated osteotomy, complete osteotomy and crestal osteotomy . Implants can be inserted simultaneously with the graft (one-stage lateral antrostomy) or at a later time (two-stage lateral antrostomy).
A more conservative sinus augmentation approach using osteotomes was introduced in 1994 by S ummers . Today a variety of modifications can be found in the literature . Based on these two principal concepts for sinus augmentation, other different and modified techniques for the crestal and lateral approach to the maxillary sinus have been introduced . The development and subsequent success of piezoelectric osteotomies has suggested new ideas for bone cutting and surgical procedures. This technical note introduces a new palatal approach to the maxillary sinus using piezosurgery for maxillary sinus elevation. Inclusion criteria were that patients had to be free of sinus pathology and have a reduced height alveolar crest at the prospective implant site. The residual height of the alveolar bone had to be less than 5 mm, which was assessed by preoperative radiographs. The minimum transversal width of the alveolar crest had to be 7 mm, which was measured during basic evaluation using a caliper. Patients were in good systemic health with no contraindications for oral surgical interventions.
Surgical technique
From the patient pool of the Department of Maxillofacial and Facial Plastic Surgery, Frankfurt, 12 fully or partially edentulous patients (seven women, five men) designated for implant treatment in the posterior maxilla were selected from March 2007 to December 2007. The study group had an average age of 55 years (range: 22–70 years). All participants had to sign written informed consent prior to the sinus augmentation procedure. The surgical procedure was performed either under general anaesthesia (four patients with bilateral sinus elevation) or local anaesthesia (eight patients with unilateral sinus elevation) by one surgeon. Following a slightly palatally located crestal and bevelled incision with an oblique releasing incision in the premolar region a full-thickness flap was raised to access the palatal bone wall of the maxillary sinus. By locating the crestal incision slightly palatally, the periosteum and the attached gingiva in the delicate vestibular and later periimplant region were preserved, because they were not opened up. The mesial palatal releasing incision in the premolar region was easy to perform and no massive bleeding of lesser palatine arteries occurred. An intraoperative coagulation procedure was not necessary.
Once the flap had been raised to allow the desired osteotomy approach it was carefully held off with fixation sutures. Owing to the lack of a distal releasing incision, the blood supply of the flap through the greater palatine artery retained its undisturbed blood circulation. No accessory cheek retractors were used. The antrostomy was performed using the piezosurgery device (Mectron, Carasco, Italy). Selected parameters for the osteotomy with the OT2 scalpel were ‘bone quality one’ with additionally water cooling (pump output of 50%). A complete window osteotomy for later palatal sinus elevation (WOLPE) was carried out with a rectangular pattern ( Fig. 1 ). The time need for piezoelectric bone cutting was comparable to the lateral approach. Palatal handling of the handpiece was as straightforward as using an instrument on the buccal part.
After osteotomy, the palatal bony lid was completely removed and the sinus membrane was meticulously dissected and lifted by elevators in a way similar to the lateral approach technique ( Fig. 2 ). In all cases, the membrane was prepared until the instruments had direct contact with the buccal plate. The empty space was grafted with a new entirely synthetic and nano-structured hydroxyapatite-based biomaterial embedded in a highly porous matrix of silica gel (NanoBone ® ). The biomaterial was mixed with blood gained from the surgical site and was densely packed into the cavity. No additional autogenous bone blocks or chips were used. After filling the whole prepared space, excessive particles of the graft material were removed and the palatal bony lid was readapted at the original place ( Fig. 3 ). The underlying bony lid could be securely stabilized in its position because of the steady fitting and the absence of muscular traction forces or functional movements.
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