Two-piece Zirconia Implants With Two Various Platforms

24 patients with missing premolar teeth and healed sockets will be recruited. They will be randomized into two groups to supplied with tissue-level (n=12) or bone-level (n=12) 10-mm long 4-mm wide zirconia implants. Primary and secondary stabilities will be measured with International Stability Quotient (ISQ) device. After 3 months, ceramic crowns will be supplied. Implant survival rates and parameters in relation to periimplant soft-tissues and bone health and anatomy will be recorded and evaluated after 1, 3 and 5 years.