Fig. 1

Study design and timeline. a Design of the Grade IV titanium implant and its surface characterization. Scale bar, 2 mm. b Illustration of the iliac crest and the static load on implants in the goat model. c Operation: implants insert parallel to each other with platform at iliac crest level. Static loading method: orthodontic Ni–Ti spring apply continuous static lateral force to the implants. Euthanasia and sample collection