Towards the limit of quantifying low-amplitude strains on bone and in coagulum around immediately loaded oral implants in extraction sockets

The purpose of this study was to quantify strains in coagulum around immediately loaded oral implants in extraction sockets at the ex vivo level. Bilateral maxillary premolar teeth of two fresh human cadavers were extracted and psi 4.1 x 12 mm Straumann TE implants were placed in the sockets of first and second premolars by utilizing mesio-distal and palatal anchorage, respectively. Installation torque value (ITV) of each implant was measured by a custom-made torque wrench and resonance frequency analyses (RFAs) were undertaken to determine intraosseous stability. Upon abutment connection, a gold coping allowing the placement of a miniature load cell to contact the underlying solid abutment was fabricated. A linear strain gauge was connected to the coping at a distance for strain measurements in coagulum around the implant neck in the extraction socket. Linear strain gauges were also bonded on the labial marginal bone of each extraction socket. Strain measurements were performed at a sample rate of 10 kHz simultaneously monitored from a computer connected to data acquisition system and under a maximum load of 100 N on each implant with or without human coagulum in the extraction socket. Low-amplitude strains were measured around immediate implants. The increase in load increased strains on labial marginal cortical bone around implants (P < 0.05). Bone strains were higher on the implant loaded, when coagulum was present in the bone defects (P < 0.05). Strains within coagulum around mesiodistally anchored implants were higher than palatally anchored implants (P < 0.05). The type of implant on anchorage and presence of coagulum has an impact mechanotransduction to buccal marginal bone around immediate implants.