Angulated implants: an alternative to bone augmentation and sinus lift procedure: systematic review.

Rehabilitation of completely edentulous patients with implant becomes challenging due to reduced amount of bone available and pneumatisation of maxillary sinus or both. To successfully treat such patients, prior to implant placement, patient has to undergo invasive procedures like sinus lift and/or bone augmentation which is not possible many time due to many reasons. This article focuses on an alternative treatment procedure in which two posterior implants are placed at an angle and two anterior implants are placed axially thereby eliminating the need for sinus lift or bone augmentation procedures. This article broadly discusses this "All on Four" concept in all aspects, its effects on bone, prosthesis survival, forces acting etc along with various related studies.