Clinical application and complications of short implants (≤6 mm)

Short implants can be used as an alternative in cases of insufficient vertical bone volume after dentition defect or absence of dentition to simplify or avoid bone augmentation procedures. Short implants (≤ 6 mm) are reported to have a mean survival rate of 96% after a period of 1-5 years in function and have been widely used in cases of dentition defects or absence of dentition. Compared with conventional implants (≥ 10 mm) combined with bone augmentation procedures, short implants have fewer surgery-related complications, less marginal bone loss, shortened treatment times and reduced costs, and are preferred by patients. Due to a lack of evidence, a high crown-implant ratio should not be an obstacle for the use of short implants. In addition, most of the current literature has not enough follow-up time, the long-term implant survival data of short implants remain unclear. To improve the clinical outcomes of short implants, attention should be paid to the implant site, bone quality, and occlusal force as well as to the presence of oral health maintenance, periodontal diseases and habits through a careful intraoral and radiographic examination. The choices of wider implant use and splint restoration are recommended, occlusal force should be paid attention during implant maintenance. Inappropriate stress on restorations should be avoided. Future studies should be focused on the long-term clinical outcomes of short implants.