Purpose: To describe the postoperative complications following lateral wall sinus augmentation using (poly L-lactideco-ε-caprolactone; PLCL) and natural polysaccharides polymers-coated bovine bone (PBB). The secondary aims were to examine histologic findings and to propose complication management alternatives.

Materials and methods: This retrospective study included 61 subjects who underwent 67 lateral wall sinus augmentation procedures using PBB in the standard protocol. In cases that presented complications, treatment included additional antibiotic therapy, implant removal, or sinus reentry and total removal of the grafting material. In three cases, biopsy specimens were taken from the sinuses, and histologic analyses were performed.

Results: The prevalence of postoperative complications was 32.8% (22 of 67 cases) in 18 of the patients (29.5%). The most prevalent symptoms were persistent pain (68.2%), swelling (63.6%), and oroantral fistula (54.5%). Radiographic signs appeared in 45.5% of the complications. A total of 24 implants failed; thus, an overall 80.3% survival rate was established at 19 months. The vast majority of complications (86.4%) were treated eventually with reentry surgery and revealed that the sinus was full with granulation tissue surrounding pieces of a nonossified rubber-like material. In cases where implants were placed, nonosseointegrated implants were surrounded by soft tissue. The sinus was cleaned thoroughly; the graft material remnants were removed together with inflamed parts of the sinus membrane, followed by chlorhexidine and saline lavages. In the biopsy specimens taken from the sinus cavity, there were no histologic features of new bone formation around the grafted material.

Conclusion: Lateral wall maxillary sinus augmentation using PBB was associated with an acute sinus infection histologic appearance and with a 7-times-higher failure rate compared with previous reports. This serious adverse event suggests that PBB cannot be recommended for maxillary sinus augmentations.