Insertion energy has been advocated as a novel measure for primary implant stability, but
the effect of implant length, diameter, or surgical protocol remains unclear. Twenty implants from one
specific bone level implant system were placed in layered polyurethane foam measuring maximum
insertion torque, torque–time curves, and primary stability using resonance frequency analysis
(RFA). Insertion energy was calculated as area under torque–time curve applying the trapezoidal
formula. Statistical analysis was based on analysis of variance, Tukey honest differences tests and
Pearson’s product moment correlation tests (α = 0.05). Implant stability (p = 0.01) and insertion energy
(p < 0.01) differed significantly among groups, while maximum insertion torque did not (p = 0.17).
Short implants showed a significant decrease in implant stability (p = 0.01), while reducing implant
diameter did not cause any significant effect. Applying the drilling protocol for dense bone resulted
in significantly increased insertion energy (p = 0.02) but a significant decrease in implant stability
(p = 0.04). Insertion energy was not found to be a more reliable parameter for evaluating primary
implant stability when compared to maximum insertion torque and resonance frequency analysis
