Survival and Success Rates of Different Shoulder Designs: A Systematic Review of the Literature

To identify whether there is a relationship between different implant shoulder positions/orientations/designs andprosthetic and/or implant failures, biological or mechanical complications, radiographic marginal bone loss (MBL), peri-implantbuccal recession (RC), aesthetic scores (Papilla Index, PES, and WES), and patient satisfaction after a minimum of 1 year function inthe aesthetic zone, compared to the two-piece, conventional implant neck architecture. Materials and Methods.)e systematic reviewwas written according to the PRISMA guidelines. )e search strategy encompassed the English literature from 1967 to September2016 and was performed online (in the PubMed database of the U.S. National Library of Medicine, Embase, and the CochraneLibrary) to identify relevant studies that met the inclusion criteria. )e assessment of quality and risk of bias of the selectedmanuscripts was performed according to the guidelines provided by CONSORT and STROBE statements. Results. A total of 16articles (7 randomized controlled trials, 4 observational comparative studies, and 5 systematic reviews) were selected to fulfill theinclusion criteria. A trend of higher implant failure and prosthetic complications were experienced in the one-piece group comparedto the two-piece group, although no statistically significant differences were found. Higher marginal bone loss was found in the testgroup (one-piece, scalloped implants) compared to the control group (two-piece, flat implants). No comparative studies reportingdata on sloped implants were found that fulfilled the inclusion and exclusion criteria of this systematic review. No differences wereexperienced between groups regarding aesthetic outcomes and patient satisfaction. Conclusions. )ere was sufficient evidence thatdifferent implant shoulder positions/orientations/designs (scalloped, sloped, and one piece) offer no benefit when compared to twopiece, conventional flat implants. Current evidence is limited due to the quality of available studies.