AutoresDaniel Robles, Saray Férnandez-Hernández, Miquel Punset, Meritxell Molmeneu, Javier Gil, Esteban Pérez-Pevida, Artiza Velasco
PURPOSE: To evaluate the biomechanical behavior, implant stability, micromotion under loading, and peri-implant bone microstrain of short dental implants (4 mm) compared with longer implants (6, 8, and 10 mm), particularly in high crownto- implant (C/I) ratio scenarios, and to assess the effect of prosthetic splinting as a biomechanical strategy. MATERIALS AND METHODS: A total of 50 implants with internal connections (4-, 6-, 8-, and 10-mm implants) were placed in 9 fresh bovine ribs and restored with standardized polymethyl methacrylate (PMMA) crowns to achieve C/I ratios of 1.22 for 10-mm implants, 1.77 for 8-mm implants, 2.7 for 6-mm implants, and 4.55 for 4-mm implants. A maximum of six implants were placed in each rib, with a 6-mm distance between implants in all cases. Using resonance frequency analysis (RFA) and controlled loading (50 N, 6-degree angulation), implant stability and micromotion were evaluated via image-based analysis. Subsequently, a subset of 4-mm implants was tested with a splinted PMMA bridge. Finite element analysis (FEA) using models consistent with the in vitro setup was performed to evaluate bone microstrain, von Mises stress, and displacement. RESULTS: Implant stability (implant stability quotient [ISQ] values) increased significantly with implant length, with the 10-mm group having the highest values (mean ISQ = 68.4) (P < .05). Micromotion and FEA displacement were inversely correlated with implant length and positively correlated with the C/I ratio. The 4-mm implants had significantly higher micromotion and microstrain values, but splinting significantly reduced both parameters and achieved a performance comparable to that of longer implants. Von Mises stress values in the peri-implant bone and abutments were highest in the 4-mm group. CONCLUSIONS: Short dental implants correlate with poorer values for implant stability than conventional implants. High C/I ratios in short implants are associated with increased micromovement and micro
