Evidence on the use of short dental implants has substantially increased in recent years. Consequently, short dental implants have expanded treatment options. Specific clinical indications currently encompass sites with a limited ridge height due to nearby anatomical structures: the maxillary sinus or the alveolar nerve in the lower jaw. In comparison with standard-length implants, however, evidence for shorter implants is limited and recommendations are more cautious. Careful case planning taking into account a variety of treatment options appears to be critical when choosing an appropriate implant length.
Feature Article
Abstract
Introduction
Implant placement has become the standard of care for partially and completely edentulous patients in the last 30 years. Over time, this treatment option has become increasingly predictable and safe, allowing more patients to benefit from it. At the same time and although standard-length implants are well documented, the field of implant dentistry is continuously evolving and new therapeutic strategies have been introduced.
In critical situations where the bone height is limited and does not allow placement of a standard-length implant, various approaches for primary or simultaneous bone augmentation such as sinus floor elevation, guided bone regeneration, distraction osteogenesis, among others, have been described (Guljé et al. 2013). These bone augmentation procedures, however, have been associated with an increased risk of surgical and post-surgical complications, increased morbidity as well as additional costs and treatment time (Esposito et al. 2011; Jung et al. 2018). Although bone augmentation procedures would allow the installation of standard-length implants in these situations, the use of short implants might be considered as an alternative (Jung et al. 2018). Using this option can avoid the need for augmentation procedures (Figs 1 and 2), thereby reducing risks associated with primary ridge augmentation (Mezzomo et al. 2014; Papaspyridakos et al. 2018).
Fig. 1: Typical splinting of a short (6-mm) implant with an adjacent longer implant after 5 years of function. With this set-up, a sinus floor elevation was not necessary, reducing not only the surgical invasiveness, but also the treatment cost
Fig. 2: A rare case with a combination of a 6-mm and a 4-mm implant in the posterior maxilla to avoid a sinus floor elevation in a 74-year-old female patient. The splinting is mandatory. The follow-up at 4 years shows stable peri-implant tissues
Fig. 1
Fig. 2
When it comes to short implants, their definition has evolved over time. Some authors defined implants with an osseointegrable component of less than 10 mm as short (Mezzomo et al. 2014), whereas other authors have suggested that 8 mm or less would qualify to be defined as short (Renouard & Nisand 2006). More recently, the proceedings of the Sixth ITI Consensus Conference reported on the survival of short implants (≤ 6 mm) compared to those longer than 6 mm (Papaspyridakos et al. 2018). Despite the lack of consensus on the definition so far, a trend over time towards the use of shorter length implants is observed.
Therefore, the aim of the present review is to highlight relevant and current scientific information on short implants as well as to offer practical answers related to the most-often asked clinical scenarios.