The reliability of pocket probing around screw-type implants

This study involved 108 patients (age 38-82 years) rehabilated with overdentures in the lower jaw supported by 2 endosseous screw-shaped implants. At each follow-up visit, the clinical attachment level (PAL) around the implants was assessed with a Merrit-B probe or a constant force electronic probe, Peri-probe, and biannually parallel long-cone radiographs were taken to locate the marginal bone level. These data were used to locate the marginal bone level. These data were used to examine to relationship between bone and attachment level estimations around implants. As a mean, bone level was scored 1.4 mm apically of PAL and this difference remained constant with time. The Pearson correlation coefficient between bone level and PAL, for mesial and distal sites, was 0.67 and 0.61 for the Merrit-B probe, and 0.76 and 0.65, respectively for the Peri-probe. The highest correlations were obtained for sites with a healthy gingiva or in absence of intra-bony craters. Duplicate PAL registrators showed a standard deviation for the intra-examiner variability of 0.37 (Peri-probe) or 0.40 mm. The mean difference in PAL between Merrit-B probe or Peri-probe was 0.05 mm. It was concluded that the clinical attachment level determination is a relaible indicator for bone level around implants with a moderate healthy gingiva.