The Impact of Immediate Implant Placement on Alveolar Ridge Preservation Techniques: a Clinical, Volumetric and Radiological Randomized Controlled Clinical Trial.

It is well known that following the loss of a single tooth, severe hard- and soft-tissue alterations may take place within the affected site, resulting in a subsequent reduction of both vertical and horizontal ridge dimensions, often not allowing neither appropiate pontic fabrication nor correct placement of endosseous implants.

Over the past 20 years, various surgical procedures, grouped under the term of "alveolar ridge preservation" (ARP), have been introduced, aiming to maintain the existing soft and hard tissue envelope as well as a stable ridge volume, simplifying subsequent treatment procedures and optimizing functional and esthetic outcomes. They have been widely tested in controlled and not controlled clinical studies with various materials and approaches, and a number of recently published systematic reviews on this topic have confirmed the efficacy of ARP in preventing post-extraction dimensional changes of alveolar ridges.

After these procedures a minimum of four to six months must be awaited before implant insertion can be performed, bringing the patient compromised comfort, function and aesthetics and needing of a second surgical procedure for the implant placement.

Dental implant insertion at the time of tooth extraction (type I or immediate placement) reduced the number of dental appointments, of surgeries required and the overall treatment time. Nevertheless this surgical protocol does not provide predictable outcomes, since it may contribute towards a more pronounced bone resorption during healing. Different anatomical factors, as the thickness of the buccal bone wall and the dimension of the horizontal gap, may influence the dimensional changes of the alveolar crest following immediate implant placement. Such morphological changes could lead to negative esthetic complications, such as marginal soft tissues recessions, especially when affecting the buccal side of maxillary sites in patients with a high smile line.

It is unknown if immediate implant placement plus grafting materials and/or barrier membranes could influence post-extraction dimensional changes of alveolar ridges. No consensus exists on the need for bone augmentation simultaneously with immediate implant placement. Furthermore, no human study has yet compared dimensional changes of both hard and soft tissues after two different treatments: an alveolar ridge preservation technique for a subsequent implant placement, and an alveolar ridge preservation technique with an immediate implant placement.