Dental implants are a viable solution for the restoration of single-tooth gaps, with high survival and success rates in the short and long term . Nowadays, the placement of an implant-supported single crown allows the rapid and predictable restoration of function (mastication) and aesthetics .
A good biological integration is an essential prerequisite for the success of a fixed implant-supported restoration . In fact, a dental implant has to effectively integrate into the bone, in order to functionally support the prosthetic restoration ; at the same time, of fundamental importance is the integration with the soft tissues, which is a guarantee of the maintenance of osseointegration over time, and it is an essential condition for the aesthetic success of the rehabilitation .
In recent years, the aesthetic requirements of the patients have become increasingly important and difficult to satisfy ; furthermore, patients require a treatment that should be fast, minimally invasive, and of low cost .
In order to meet the modern needs of patients, new surgical and prosthetic protocols have been proposed and are gaining acceptance, which reduce the number of operating sessions (and with them the stress and costs for the patient): among them, there are the placement of implants in fresh extraction sockets and the immediate prosthetic loading .
The placement of implants in fresh extraction sockets, that is, immediately after the extraction of the nonrestorable, compromised teeth, can reduce the number of surgical sessions (from two to one) with a reduction in the patients’ stress and costs . This strategy is compatible with the insertion of implants with a flapless technique (i.e., without having to raise a full-thickness, mucoperiosteal flap) and is therefore minimally invasive: this represents a further advantage of the method . Finally, some researchers believe that the insertion of an implant into a fresh extraction socket may facilitate the correct three-dimensional (3D) positioning of the fixture, with benefits for the emergence profile .
Although all these benefits of immediate implant placement have been recognized, this surgical technique does not allow (in contrast to what had been assumed in the past) a reduction or counteracting of the physiological resorption that occurs in the alveolar bone after tooth extraction , and that particularly affects the delicate buccal bone plate in the anterior maxilla . In addition, the placement and primary stabilization of an implant in a fresh postextraction socket (which is generally larger) can be technically difficult and can be a challenge for the surgeon . If the implant is placed too buccally, the final aesthetic outcome can be compromised ; if the implant is placed too palatally (lingually), this situation may not be compatible with adequate prosthetic emergence profile .
The immediate prosthetic loading is a viable strategy to reduce the time of treatment: the placement of a temporary restoration immediately after the insertion of the fixture (within 48–72 hours after surgery) is certainly an aesthetic and functional benefit to the patient, who can avoid wearing uncomfortable removable dentures during the healing period . Finally, the placement of an immediate provisional restoration involves benefits with respect to gingival tissues, which can be modeled around it immediately .
However, there is a risk to be calculated in immediate loading of dental implants, especially when they support single crowns : in order to obtain a valid osseointegration, it is indeed necessary that the forces applied on the system in the early healing period are controlled, and they do not generate micromotions . The presence of micromovements at the interface between bone and implant can, in fact, affect bone healing and osseointegration, leading to a mobilization and failure of the implant .
In order to meet the new challenges of modern implantology, the manufacturers now offer implant systems with specific designs (macrotopographies) and surfaces (micro/nanotopographies) that can help to maximize the primary stabilization in difficult contexts (such as the placement in postextraction sockets) and at the same time speed up and enhance osseointegration, in order to anticipate the prosthetic loading without risk .
The aim of this prospective clinical study is therefore to present the clinical outcomes of single implants with a knife-edge thread design and a nanostructured calcium-incorporated surface, when placed in postextraction sockets and healed sites of the anterior maxilla and subjected to immediate loading.