The purpose of this clinical study is to evaluate the clinical and radiographic efficacy of Theravex Tissue Care Plus (Bone Bioactive Liquid) as an adjunct to a xenograft in crestal maxillary sinus elevation with simultaneous implant placement using the osseodensification technique. The study will enroll 16 partially edentulous patients who have inadequate posterior maxillary bone height. Participants will randomly undergo the sinus elevation and implant placement utilizing either a xenograft alone or a mixture of the xenograft and Theravex. The main question the study aims to answer is whether the adjunctive use of Theravex with a xenograft enhances vertical bone gain, bone density, and implant stability compared to using a xenograft alone.