PROBING PERI‐IMPLANT TISSUES

For many years it was incorrectly assumed that the tip of the periodontal probe in a probing depth (PD) measurement identified the apical base of the dento‐gingival epithelium. Later research documented, however, that this was not the case. At healthy sites the tip of the probe failed to reach the apical portion of the epithelial barrier, while at diseased sites the probe found the apical base of the inflammatory cell infiltrate. Hence, PD measurements assess the depth of probe penetration or the resistance offered by the soft tissue.

The influence of the condition (health, disease) of the peri‐implant mucosa on the outcome of the probing measurement was studied in animal models. Lang et al. reported that at sites with healthy mucosa or mucositis, the tip of the probe identified the apical border of the barrier epithelium with an error of approximately 0.2 mm, while at sites with peri‐implantitis, the measurement error was much greater at 1.5 mm. Abrahamsson and Soldini, in a subsequent study, stated that the probe penetration into the healthy soft tissues at the buccal surface of teeth and implants in dogs was alike and similar to the length of the junctional/barrier epithelium. It was assumed that probing the implant–mucosa interface would sever the soft tissue seal and jeopardize the integrity of the adhesion. This issue was examined in a dog study that documented that already after 5 to 7 days following clinical probing, the soft tissue seal had regenerated to its full extent.