Maxillary sinus floor augmentation with injectable calcium phosphate cements: a pre‐clinical study in sheep

Objectives The aim of this pre‐clinical study was to evaluate the biological performance of two injectable calcium phosphate cement ( CPC ) composite materials containing poly(D,L‐lactic‐ co ‐glycolic)acid ( PLGA ) microspheres with different properties in a maxillary sinus floor elevation model in sheep. Materials and methods PLGA microspheres were made of either low molecular weight (~17 kDa) acid‐terminated PLGA ( PLGA L‐AT ) or high molecular weight (~44 kDa) end‐capped PLGA ( PLGA H‐EC ) and incorporated in CPC . Eight female Swifter sheep underwent a bilateral maxillary sinus floor elevation procedure via an extra‐oral approach. All animals received both materials, alternately injected in the left and right sinus (split‐mouth model) and a time point of 12 weeks was used. Analysis of biological performance was based on histology, histomorphometry, and evaluation of sequential fluorochrome labeling. Results Both types of CPC ‐ PLGA composites showed biocompatibility and direct bone‐cement contact. CPC ‐ PLGA L‐AT showed a significantly higher degradation distance compared to CPC ‐ PLGA H‐EC (1949 ± 1295 μm vs. 459 ± 267 μm; P =  0.0107). Further, CPC ‐ PLGA L‐AT showed significantly more bone in the region of interest (26.4 ± 10.5% vs. 8.6 ± 3.9% for PLGA H‐EC ; P  =   0.0009) and significantly less remaining CPC material (61.2 ± 17.7% vs. 81.9 ± 10.9% for PLGA H‐EC ; P =  0.0192). Conclusions Both CPC ‐ PLGA L‐AT and CPC ‐ PLGA H‐EC demonstrated to be safe materials for sinus floor elevation procedures in a large animal model, presenting biocompatibility and direct bone contact. In view of material performance, CPC ‐ PLGA L‐AT showed significantly faster degradation and a significantly higher amount of newly formed bone compared to CPC ‐ PLGA H‐EC .