Abstract
            Background. Xenograft and allograft bone substitutes are widely used to replace the missing  bone in defects. Since removing the packaging of these grafts can nullify their sterilization, this  study aimed to evaluate the sterility and bioactivity changes of an allograft and a xenograft  following uncapping/recap.  
  Methods. Two types of commercial allograft and xenograft vials were unpacked and further  exposed to operating room air, where implant surgery was performed for one second, ten  minutes, and one hour. After three repetitions, samples were analyzed using microbiological  tests and scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDX) for  sterility and bioactivity evaluation.  
  Results. None of the bone graft samples showed microbial growth or bioactivity-negative  changes after seven days of unpacking the vials.  
  Conclusion. Despite the positive results of this study, future studies and more analysis  considering influential factors are required. Also, disinfection and air exchange must still be  observed during biomaterial application and bone grafting procedures.