Posterior Maxilla
Posterior maxilla has very poor quality of bone demanding special consideration in implant placement:
Increasing the number of implants to decrease the crestal stresses.
Hydroxyapatite coatings(HA) on implant to improve surface contact betweenthe implant and bone
Use of threaded implant design(deep threads)which increase the surface area of support
Use of relatively longer and wider implants for initial stability and early loading.
The maintenance of the 2mm one of safety from the opposing anatomic landmark for implant placement is not indicated in posterior maxilla. As long as the rotary instruments do not perforate the thin cortical plate and/or membrane lining of sinus, no contraindications exist to preparation or implant placement within this boundary.