Threaded Implants in the Atrophic Posterior Mandible

Partial edentulism in the posterior mandible is a common clinical issue, particularly with the early loss of molars and premolars. Rehabilitation of patients with this deficiency can be achieved using a removable prosthesis, but this solution does not guarantee optimal function and is often declined by patients for comfort or psychologic reasons. In addition, denture-associated plaque accumulation can result in further caries in the remaining teeth and damage to the periodontal tissue, and poor denture design can lead to tooth mobility and even tooth loss. For these reasons and the reported successful long-term outcomes with dental implant-supported fixed restorations, this option has become the treatment of choice for the posterior mandible among clinicians and patients alike. As originally prescribed for machine-turned (ie, Brånemark-type, Nobel Biocare) threaded implants, many clinicians still believe that predictably successful treatment requires longer (ie, at least 10 mm) implants in the posterior mandible. However, if the teeth intended for replacement have been missing for many years or if their removal was traumatic (causing excessive bone loss), there may be inadequate bone volume to allow placement of standard-length implants. Deficits in bone can be vertical, horizontal, or both. This chapter focuses on the use of short and ultra-short moderately rough threaded implants (MRTIs) from several manufacturers for sites with advanced vertical bone atrophy in the posterior mandible in combination with adequate buccolingual alveolar ridge width (Seibert Class II). Guidelines, clinical indications, advantages, and disadvantages are given with a special focus on short and ultra-short implants as an alternative to vertical bone augmentation.