Simulated bone for dental implant in vitro testing: A systematic review

OBJECTIVE: To evaluate methodological factors in the fabrication of simulated bone for dental implant testing and assess their relationship with reported clinical failure patterns. METHOD: A systematic search was conducted in MEDLINE/PubMed, Scopus, and Web of Science following PRISMA. In-vitro studies published from 2015 on mechanically testing single-unit implants with simulated bone materials were included. Two reviewers performed screening, data extraction, and RoBDEMAT appraisal. Disagreements were resolved by a third reviewer. A narrative synthesis categorized bone material characteristics, bone loss simulation, loading angulation, and implant connection type, analyzing their influence on reported outcomes. RESULTS: From 2,472 records, 91 studies met the inclusion criteria. Most studies used single-layer simulated bone (81/91), predominantly autopolymerizing resins, while 10 employed two-layer cortical-cancellous bone analogs. Bone loss was mostly simulated using 3 mm (n=41). Loading was commonly applied at 30° (n=61), followed by 0° (n=21). The most frequent outcomes were screw loosening (n=21), screw fracture (n=19), abutment fracture (n=19), crown/veneer fracture (n=19), and implant fracture (n=19). Off-axis loading (30-45°) combined with crestal bone loss (∼3mm) tended to shift failures from screw/abutment to implant fractures. CONCLUSIONS: Reported laboratory failures partly align with clinical observations. Simulated bone loss level, bone stiffness and loading angle can influence failure patterns in dental implant testing. ISO 14801 and related standard protocols require update to better reflect current clinical data. CLINICAL SIGNIFICANCE: Current laboratory tests do not fully reproduce contemporary peri-implant bone stability, limiting their clinical applicability. More realistic bone analogs may improve the clinical relevance of in-vitro studies.