This is a research study to test the clinical outcome of Trabecular Metal™ Dental Implants (TMDI) (Zimmer Dental Inc Carlsbad, CA, US) in the Maxillary Sinus region. This project will enroll 30 active subjects who will receive two dental implants in the edentulous maxillary molar region. This 24-month research study will examine the clinical stability of TMDI in both sinus elevation and sinus augmentation environments. The proposed research lays the foundation for improved health care by providing surgeons and restorative dentists with data for determining the effects TMDI have on clinical success in less than optimal osseous environments. The rationale that underlies the investigation is that identification of the influences of trabecular surface design on implant stability in varying bone types will allow routine, predictable use of early loading, which, in turn, will translate into more rapid, economical health care, and improved psychosocial well-being of the patient. If these hypotheses are correct, the results are expected to provide evidence based research data to support early loading and immediate loading of single implants in sites of adequate bone volume, and density with or without the use of graft materials in sinus lift procedures. In addition, it is expected that these results will fundamentally advance the field of implant dentistry and bioengineering by providing information on the principles of the bone density-mechanical environment-implant stability interaction.