Susan Parker RDH, B.S., MEd, MBA
Depending on the periodontal tissue conditions, increasing periodontal probing pressure also increases the periodontal probing depth (PPD).
The results of this well conducted systematic review, although having significant heterogeneity in the included study methods, suggest that periodontal probing techniques may influence PPD measurements.
When using a periodontal probe with a tapered probe tip in periodontal pockets, what is the effect of different probing pressures of the recorded PPD?
The authors searched two databases for articles only published in English up to June 2008. They also hand searched the references of the accepted papers. Their search terms included variations such as problem (periodontal pocket), intervention (periodontal pressure probe) and outcome (periodontal pocket, gingival pocket or probing pocket depth). Two independent reviewers screened and selected papers. The authors considered the following factors on probing depth measures: number of subjects, periodontal tissue condition, sites, probes, probing pressures and methodological quality assessment. In addition, parameters such as allocation concealment, randomization, blinding and loss to follow-up were also considered.
Five papers met the selection criteria and were included for this systemic review. The studies included both male and female adults with diseased and healthy periodontal tissue. The authors assessed sites ranging between 11 and 413. The probing pressure (N/cm2) in these studies was calculated based on probing force or probe diameter. The extent of probe penetration also was reported. None of the patients/sites was lost to follow-up. At healthy/treated sites, a mean increase of PPD of 0.002 mm per increase of 1N/cm² in probing pressure was calculated, whereas at diseased sites this value was 0.004 mm.
Increases in probing pressure increases the probing pocket depth . The magnitude of the increase in probing depth depends on the on the periodontal tissue condition.
Source of Funding:
The study was self-funded by the authors and Academic Centre for Dentistry, Amsterdam.
Importance and Context:
A periodontal probe assesses the depth of a periodontal pocket, an important aspect of the diagnosis and treatment of periodontitis. A number of factors of affect the measurement of periodontal probing depth. Because probing pressure is a product of probing force (N) relative to the tip diameter (mm) there appears to be a relationship between probing force and pocket penetration.1 Accurate measurement of PPD is critical for assessing periodontal status, establishing diagnosis and developing of a treatment plan.
Strengths and Weaknesses of the Systematic Review:
This systematic review followed generally accepted guidelines. The authors' question was well-defined. Their search strategy was adequate. Inclusion and exclusion criteria were clearly stated and they formed a detailed search strategy. They considered the methodological quality of the studies and risks of bias.
Strengths and Weaknesses of the Evidence:
The included studies had considerable heterogeneity in their designs, characteristics and outcome variables. The authors' method of randomization in the studies was unclear. Probing pressures (mean probing depth per probing force/pressure and standard deviation) varied among the studies, ranging from 51 to 995N/cm². As variations in probe tip diameters could produce different results, it was decided to include only studies in which probes controlled the delivered force or a probing force indicator was used. In all studies none of the patients/sites was lost to follow-up during the testing period.
Implications for Dental Practice:
A clear trend was found in the study were an increase in probing pressure and/or a decreased probing tip diameter increases the periodontal probing depth. This increase depends on the condition of the periodontal tissues. Inflamed tissues will offer less resistance to probing pressure.
1. Hassell TM, Germann MA, Saxer UP. Periodontal probing: interinvestigator
discrepancies and correlations between probing force and recorded depth. Helv
Odontol Acta. 1973 Apr;17(1):38-42.