Long-Term Clinical, Microbiological, and Radiographic Outcomes of Brånemark™ Implants Installed in Augmented Maxillary Bone for Fixed Full-Arch Rehabilitation

Abstract

Purpose: The purpose of this study was to document the long-term outcome of Brånemark implants installed in augmented maxillary bone and to identify parameters that are associated with peri-implant bone level. Material and Methods: Patients of a periodontal practice who had been referred to a maxillofacial surgeon for iliac crest bone grafting in the atrophic maxilla were retrospectively recruited. Five months following grafting, they received 7-8 turned Brånemark implants. Following submerged healing of another 5 months, implants were uncovered and restorative procedures for fixed rehabilitation were initiated 2-3 months thereafter. The primary outcome variable was bone level defined as the distance from the implant-abutment interface to the first visible bone-to-implant contact. Secondary outcome variables included plaque index, bleeding index, probing depth, and levels of 40 species in subgingival plaque samples as identified by means of checkerboard DNA-DNA hybridization. Results: Nine out of 16 patients (eight females, one male; mean age 59) with 71 implants agreed to come in for evaluation after on average 9 years (SD 4; range 3-13) of function. One implant was deemed mobile at the time of inspection. Clinical conditions were acceptable with 11% of the implants showing pockets≥5mm. Periodontopathogens were encountered frequently and in high numbers. Clinical parameters and bacterial levels were highly patient dependent. The mean bone level was 2.30mm (SD 1.53; range 0.00-6.95), with 23% of the implants demonstrating advanced resorption (bone level>3mm). Regression analysis showed a significant association of the patient (p