Maxillary sinus floor augmentation Carlo Mazzocco using bioactive glass granules and

This clinical study was undertaken to: 1) evaluate the use of bioactive glass BiogranTM combined with autogenous bone as grafting material for maxillary sinus augmentation with simultaneous implant placement using radiography and histology; and 2) document the short-term post-loading success of implants inserted in sinus cavities augmented with this material. Unilateral or bilateral sinus augmentation was performed in 12 patients with 3–5 mm of alveolar crestal bone height in the posterior maxilla prior to grafting. The sinuses were grafted with bioactive glass mixed in a 4:1 ratio with autogenous bone. Simultaneously, 2–3 threaded titanium implants were inserted into the augmented sinuses. Second stage surgery was carried out 9 to 12 months post implantation. At abutment connection, 10 core biopsy specimens were taken from different grafted sites and evaluated histologically. All 27 implants were clinically stable at second stage surgery. A mean increase in mineralized tissue height of 7.1∫1.6 mm was evident when comparing the pre-surgical CT scans with those performed 9–12 months following the sinus augmentation procedure. Evaluation of the cores yielded a mean of 30.6∫5.7% of bone tissue in the grafted sites. One implant failed during the prosthetic phase while the remaining 26 implants were stable 12 months post loading. This study suggests that BiogranTM/autogenous bone graft combination used in onestage sinus augmentation yields sufficient quality and volume of mineralized tissue for predictable simultaneous implant placement in patients with 3–5 mm of bone height prior to grafting. Sinus grafting procedures using autogenous bone and other bone substitutes have been shown to be a safe technique with high predictability of success (Hirsch & Ericsson 1991; Misch et al. 1991; Smiler et al. 1992; Raghoebar et al. 1993; Betts & Miloro 1994; Hürzeler et al. 1996). Various bone grafting materials have been used in sinus augmentation including autogenous grafts (Hirsch & Ericsson 1991; Raghoebar et al. 1993; Lundgren et al. 1996), freeze-dried bone allografts (Smiler et al. 1992; Nishibori et al. 1994), hydroxyapatite (Wagner 1991; Moy et al. 1993; Wheeler et al. 1996), and xenografts (Smiler et al. 1992; Valentini & Abensur 1997). Although the results of these investigations indicate that sinus augmentation is clinically successful with various graft materials, it is not established which of these materials, except for autogenous bone, provide better osteogenic potential and biomechanical properties. Autogenous bone remains the material of choice currently available for bone reconstructive procedures (Wood & Moore 1988; Hirsch & Ericsson 1991; Moy et al. Cordioli et al . Sinus augmentation using BiogranTM with simultaneous implant placement 1993). However, its use can be limited for the following problems: a) donor site morbidity; b) limited amounts of graft material that can be harvested intraorally; and c) need for general anesthesia for bone harvesting from extra-oral sites in cases of major augmentation procedures. Recently, bioactive glass has been subjected to intensive experimental and clinical use as a bone substitute in periodontal and various osseous reconstructive applications (Schepers et al. 1991; Schepers et al. 1993; Wilson et al. 1993; Furusawa & Mizunuma 1997; Low et al. 1997; Schepers & Ducheyne 1997). BiogranTM is a resorbable amorphous bioactive glass of 300–355 mm particle size. It is composed of 45% silicon dioxide (SiO2), 24.5% calcium oxide (CaO), 24.5% sodium oxide (NaO2), and 6% phosphorous pentoxide (P2O5). It has been shown to enhance bone repair not only by the osteoconductive properties of the particles, but also by their osteostimulative potential defined as bone formation within internal pouches excavated within the bioglass particles away from the pre-existing bony defect walls (Schepers & Ducheyne 1997). The aim of the present study was to clinically, radiographically and histologically evaluate the use of BiogranTM grafting material in maxillary sinus elevation procedures with simultaneous implant placement in humans. It was also the purpose of this report to document the short-term clinical success of fixtures inserted in the sinus cavities augmented with BiogranTM. Material and methods Preoperative evaluation Twelve patients were selected for the sinus elevation and implant placement procedure based on the following inclusion criteria: 1) maxillary total or partial (unilateral or bilateral) edentulism involving the premolar/molar areas; and 2) presence of 3–5 mm of bone from the edentulous crest level to the maxillary sinus floor as evidenced at the baseline preoperative radiographic examination. The following patients were excluded from the study: a) smokers; b) patients with systemic contraindications to oral 271 | Clin. Oral Impl. Res. 12, 2001 / 270–278 surgical procedures and implant therapy; c) patients with recent extractions (less than 1 year) in the involved area; d) patients with thin ridges which may not allow immediate primary stability; and e) patients with ongoing pathology of the maxillary sinus. At the initial visit, all patients received a radiographic (periapical and panorex), clinical and occlusal examination. Computerized tomographic (CT) scans were carried out in all patients using surgical stents with radiopaque markers in the planned position of the fixtures. The radiographic criteria of thickness (Ø4 mm) and height (3–5 mm) of the remaining alveolar bone below the sinus floor were re-assessed more accurately on the CT scans.