Probing at implants with peri-implantitis and its relation to clinical peri-implant bone loss

To evaluate the probing depth at implants with signs of peri-implantitis before and following the removal of the prosthetic reconstructions and its relation with the peri-implant bone level as revealed by open access flap surgery.

Twenty-nine patients with 89 implants with diagnosis of peri-implantitis were included in the study. The probing pocket depth at implants before (PPD-1) and following (PPD-2) the removal of the prosthetic reconstructions was measured at four sites of the implants. These measurements were also analysed in relation to the amount of peri-implant bone loss measured during peri-implant surgery.

The results showed that in only 119 (37%) of the sites, the measurements were similar between PPD-1 and PPD-2; in 124 sites (39%), the difference was ±1 mm, in 47 sites (15%) it was ±2 mm and in the rest of the sites it was ±3 mm. A high linear and statistically significant (P = <0.001) correlation between PPD-2 and the bone loss measured at implants for all and single surfaces was observed (r = 0.67, range 0.64-0.69), while PPD-1 yielded a weak and no statistically significant correlation (r = 0.35, range 0.27-0.42). The analysis of the bone loss at implants showed that 59 implants (66%) had an amount of bone loss that was similar at all the four surfaces, while in 30 implants, the bone loss differed for the various sites. A higher extent of bone loss was often detected at the buccal compared with the other sites.

The results of this study yielded differences in the pocket probing measurements at implants with or without the prosthetic reconstruction in place and that the probing pocket depth following the removal of the prosthesis had a high correlation with the amount of bone loss at implants assessed during surgery.