Depth-force-patterns in periodontal probing.

This investigation was undertaken to study penetration-depth and simultaneous force development during the insertion of a standard periodontal probe tip into a pocket to gain information about the tissue resistance to probing and its relation to the accuracy of depth determination. A piezoelectric force transducer and a linear position transducer were incorporated into a periodontal probe. Depth-force diagrams were obtained on an x-y plotter. In 5 patients requiring treatment for chronic periodontitis, 50 sites were selected and measured 3 times before and 3 times after a treatment phase consisting of hygiene instruction, systematic deep scaling and root planing. The minimal required probing force for reproducible values within a limit of 0.5 mm up to a force of 1.2 N was determined for each record ("b-value") and correlated in a multiple linear regression analysis with a number of clinical parameters of the sites. Depth-force diagrams recorded with the probe showed the characteristics of saturation curves flattening off in the range of 1 N and more. When the probing force was increased from 0.41 N up to 1.2 N, 50% of all measurements showed an increase in depth of more than 0.5 mm. However, increasing from 0.9 to 1.2 N resulted in a change of more than 0.5 mm in only 5% of the measurements. Differences in b-values before and after the treatment were significant (p less than 0.01). Differences related to tooth type (M, PM, I) and conventional pocket depth before treatment were also significant (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)