The ultimate goal of all of these preservation and augmentation procedures is the stability of the grafted site and long-term survival of implants placed in augmented sites.
Implants placed in sites grafted with additive techniques have shown high survival rates over several years. In fact, the cumulative implant survival rates in sites of autogenous block grafts harvested from chin, ramus, or iliac crest are as high as 98.1% at 3 years and 93.9% at 5 years. 61 In regard to guided bone regeneration with or without bone substitutes, a systematic review by Donos et al,62 showed comparable survival of implants placed in augmented sites versus pristine sites (91.7-100% in augmented and 93.2%-100% in pristine sites) for a period of 12-59 months. This was further supported by a 5-10 year follow up retrospective analysis of dental implants placed in grafted versus non grafted site by Tran et al.63
Procedures involving modification of existing bone may have high implant survival rates as well. The implant survival rates for split crest techniques and distraction osteogenesis are 97% and 96%, respectively.36,64 Similar conclusions cannot yet be drawn for osseodensification as evidence is limited.42 It is important to note that many of the studies are short-term, and higher quality human studies with extended follow-up periods are needed for more conclusive findings of long-term implant survival in the aforementioned procedures.36,42,64
Though these procedures yield successful results in long- and short-term studies, multiple factors such as patient selection, compliance and operator expertise play a critical role in defining the outcomes of therapy rendered.