Survival rate evaluation of short implants – A retrospective study

Background

Implant length was considered a risk factor for the long-term success of implant-supported restorations. The development of new short implant designs with new surfaces has enabled implant rehabilitation, eliminating or reducing the need for bone reconstruction, with success rates similar to longer implants

Aim/Hypothesis

the present study aims to evaluate the survival rate of 101 short implants (≤8.5 mm), installed in the posterior maxillary and mandible regions, with a minimum follow-up of one year after prosthetic rehabilitation.

Material and Methods

For the present study, 54 medical records of patients attended at the Specialization Course in Implant Dentistry of the São Leopoldo Mandic Post Graduation Center between February 2007 and February 2014 were evaluated. Short implants for this study were those with a length ≤ 8.5 mm. The records were manually reviewed and those with short implants were separated and the following data were evaluated- date of installation, model and dimensions of the implants, if there was grafting at the time of implant installation, date of prosthetic rehabilitation, date of implant loss (when it occurred), possible cause of the loss, and date of the last review. Implants with at least 1 year of follow-up were included in the study after the installation of the prostheses. The following criteria were used to exclude patients- heavy smokers (more than 10 cigarettes day), decompensated diabetics, pregnant women, use of bisphosphonates, bruxism, and patients with unrealistic expectations.

Results

This retrospective clinical study evaluated 101 short implants installed in 45 patients, 10 of whom were male and 35 were female. Seven implants were rehabilitated as part of total metalloplastic prostheses and 94 supporting metal-ceramic crowns, with 93 prostheses splinted and 08 single crowns. Seventeen implants were implanted with grafts performed at the same surgical time. The mean time between implant installation and prosthetic rehabilitation was 7.7 months (SD 5.4) and the mean follow-up time was 48.0 months (SD 19.4). During the follow-up time, 03 implants were lost, a 4.0 x 7 mm MKIII TiU® (Nobel Biocare, Yorba Linda, CA, USA), a MK III TiU Groovy® (Nobel Biocare, Yorba Linda, CA, USA).) of 4.0 x 8.5 mm and an MK III Shorty® RP (Nobel Biocare, Yorba Linda, CA, USA) (5.5 mm intraosseous height). The total survival rate of the implants was 97.02%.

Conclusion and Clinical Implications

Short implants present as a viable and safe treatment option for patients with a low residual ridge available, in a less traumatic and costly way, allowing more people to benefit from Implantology.