Clinical Outcome of Implants Placed in Staged Maxillary Sinus Augmentation Using Bovine Bone Mineral Mixed with Autogenous Bone at Three Different Ratios: A 5-Year Prospective Follow-up Study

To evaluate the 5-year clinical outcomes for implants placed in a staged sinus floor elevation (SFE) procedure and to compare three patient groups with sinus grafts with three different ratios of bovine bone mineral (BBM) and autogenous bone (AB) mixture.

A 5-year prospective cohort study was conducted on 81 patients with 119 staged SFEs non-randomly distributed to three groups based on the origin of the AB and the mixture ratio with BBM: group 1 (locally harvested AB [LHB] from osteotomy sites + BBM, ratio: 1:10), 31 patients, 37 SFEs; group 2: (LHB + intraorally harvested peripheral AB [IHPB] from retromolar/chin region + BBM, ratio: 1:4), 22 patients, 29 SFEs; and group 3 (LHB + extraorally harvested peripheral AB [EHPB] from iliac crest/tibia + BBM, ratio 1:1), 28 patients, 53 SFEs. After graft healing (5 to 7 months), 284 dental implants (group 1: 76, group 2: 61, group 3: 147 [overall: 2.3 implants/sinus]) were placed. After an additional healing period (5 to 7 months), all implants placed were functionally loaded and prospectively followed by clinical and radiographic evaluations assessing implant survival/success rate as well as peri-implant marginal bone level (MBL) alteration at 1, 3, and 5 years postloading.

A total of 76/81 patients with 267/284 implants were followed for up to 5 years (dropouts: 5 patients/15 implants; implant loss = 2). The 5-year implant survival and implant success rate (group 1: 100%/98.6%; group 2: 98.3%/96.6%; group 3: 99.3%/95.7%) did not differ between the three graft mixture groups. The peri-implant marginal bone alteration (reduction) averaged over all 5 years was 1.40 ± 0.29 mm for group 1, 1.41 ± 0.22 mm for group 2, and 1.46 ± 0.46 mm for group 3 (P = .187). However, over time, a continual and significant MBL reduction (P = .045) was noted for all groups presenting peri-implant MBL changes between 1 year and 5 years of -0.17 mm (group 1), -0.12 mm (group 2), and -0.24 mm (group 3), respectively.

According to the clinical results obtained, dental implants inserted in grafted (staged) SFE using a mixture of BBM with a minimal amount of AB harvested from local sites provide for similarly high 5-year implant/augmentation success rates as graft mixtures with AB harvested from peripheral intraoral or extraoral donor sites, confirming no need for additional bone harvesting.