Principles of tissue engineering are used today in an attempt to reconstruct damaged human tissue. In the dental field, several types of bone grafting materials are currently available which could be directly used to augment atrophic jaws before implant placement. However, the main drawback of these grafts is related to difficulty of preserving the required shape of the graft during the healing time [1]. Protecting the grafting material using titanium meshes or other temporary devices may not be applicable in non-accessible areas. Nevertheless, using autogenous bone blocks may not be an acceptable option for many patients due to the expected morbidity of the donor site [2].

Today, different types of pre-shaped bone grafting materials are currently available for augmenting atrophic ridges. One of the greatest challenges facing successful ridge augmentation is to maintain the desired shape after soft tissue closure [3]. Several studies reported a high rate of bone resorption after insertion of implants in bone augmented ridges [4, 5]. On the other hand, porous non resorbable scaffolds have the advantage of maintaining ridge shape and dimensions during healing time.

Yttrium partially stabilized tetragonal zirconia polycrystalline material, known commercially in the dental field as zirconia, was first used in orthopedic surgery as a hip joint prosthesis [6]. Soon the material gained diverse applications in the dental field as a core and framework material, implant abutment, implant fixture, and a bone scaffold as well. Using computer-assisted design and milling technology (CAD/CAM), the fabrication of accurate and precise restorations became a simple procedure [3, 7].

One of the desired features of a bone scaffold is to resist functional loads as well [8]. Several studies evaluated bone reaction against optimized zirconia scaffold surfaces [9]. Studies ranging from cell culture to full scale animal models have indicated that osteointegration observed on optimized zirconia surfaces was equal if not superior to different materials, namely titanium alloy. These studies either focused on optimizing the surface structure of zirconia scaffolds controlling its porosity, geometric structure, and micro-roughness, or by coating the surface with a bioactive layer to enhance the process of osteogenesis ability [10,11,12,13]. Porous zirconia scaffolds could also be used as a drug delivery vehicle to enhance bone response as well [14]. A recent study attributed enhanced cell viability to the internal structure of the scaffold rather than to the type of coating material used [15].