Comparison of the validity of periodontal probing measurements in smokers and non-smokers.

AIM: To determine whether the reduced inflammation and bleeding and increased fibrosis reported in tobacco smokers affect the validity of clinical probing measurements by altering probe tip penetration. METHOD: A constant force probe was used to measure probing depths and sound bone levels at six sites on 64 molar teeth (384 sites) in 20 smoking and 20 non-smoking patients from grooves made with a bur at the gingival margin prior to extraction. Connective tissue attachment levels were measured from the grooves with a dissecting microscope following extraction. Data were analysed using robust regression with sites clustered within subjects. RESULTS: Sites in smokers showed more calculus but less bleeding than sites in non-smokers (p<0.05). The mean clinical probing depth was not significantly different (smokers: 5.54 mm, confidence intervals=4.81 to 6.28; non-smokers: 6.05 mm, ci=5.38 to 6.72). The corresponding post-extraction pocket depth measurements (smokers: 4.95 mm, ci=4.30 to 5.61; non-smokers: 5.23 mm, ci=4.49 to 5.96) were less than clinical probing depth in sites from both smokers and non-smokers (p<0.01). However, the proportional difference was less in smokers (p<0.05), particularly in deeper pockets, indicating that clinical probe tip penetration of tissue was greater in non-smokers. Regression analysis indicated that the presence of calculus and bleeding also influenced the difference in clinical probe penetration (p<0.05). CONCLUSION: Clinical probing depth at molar sites exaggerates pocket depth, but the probe tip may be closer to the actual attachment level in smokers due to less penetration of tissue. This may be partly explained by the reduced inflammation and width of supra-bony connective tissue in smokers. These findings have clinical relevance to the successful management of periodontal patients who smoke.