Although the variations of the materials and methods for BMAC preparation were discussed, this review was not aimed to compare materials and methods for BMAC preparation, but rather the end clinical result for new bone formation and implant survival. Although implant survival and new bone formation were not the only parameters to consider when evaluating sinus augmentation, these parameters were the only ones consistently evaluated and reported by the existing literature to date; thus, these parameters were the ones emphasized in this systematic review. However, it is important to realize that BMAC may be of significance for other aspects of wound healing during sinus augmentation like immediate post-operative pain or soft tissue healing. And parameters should be evaluated in future studies of BMAC use in maxillary sinus augmentation.

Collectively, the papers selected for this systematic review were well written and peer-reviewed by clinicians in private practice and academic professors. However, risk of bias cannot be avoided. Sauerbier et al. [14] used selective bar graphs for histological diagnoses. Bar graphs have the potential for bias when the x and y axes are skewed to favorable results. Payer et al. [2] compared bovine with tibia bone marrow aspirate plus bovine bone. Their data show high variation of data and low numbers of patients. The result of no benefit to tibia bone marrow aspirate may be biased by the low numbers of patients. Histologically, Payer et al. [2] used 30-μm sections showing images of new bone reported as percentage of bone contact. The varying thickness of micron sections in histological preparation could influence bone contact data and percentage of new bone formation, even though the flow cytometry used to diagnose phenotypes of bone marrow stromal cells is very innovative and highly accurate. Furthermore, to reduce risk of bias, dual examiners to standardize histologic interpretation should be utilized in clinical studies of this type.