Clinical Performance of Splinted 4.5-mm Extra-Short Implants: A Controlled Retrospective Cohort Study

This study compared the survival, marginal bone loss (MBL), and prosthetic complications of 4.5-mm extra-short implants and longer implants splinted to the short implants via the restoration. A retrospective controlled cohort study was performed. The 4.5-mm extra-short group (study group; SG) included 48 consecutively placed implants. The control group (CG) included 48 implants splinted to the extra-short implants. The same surgical team treated the 39 included patients, and all implants were restored with a screw-retained fixed restoration and intermediate abutments. Im- mediate and conventionally loaded implants were included. All implants were in function during the follow-up period (14 ± 3.4 and 17 ± 13 months for SG and CG, respectively). No differences in techni- cal complications were observed between the groups (one and two cases of screw loosening for SG and CG, respectively; two provisional prosthesis fractures for SG; P = .310). Marginal bone stability was similar for SG and CG at the mesial level (–0.01 ± 0.28 mm for SG vs –0.18 ± 0.72 mm for CG; P = .270) and at the distal level (0.02 ± 0.39 mm for SG vs –0.18 ± 0.68 mm for CG; P = .076). The same good clinical performance could be observed for 4.5-mm implants and longer implants under the same prosthesis.