Patients' illness perception before and after non-surgical periodontal therapy: A pre-post quasi-experimental study

Patient's illness perception, assessed through the Brief-Illness Perception Questionnaire (Brief-IPQ), plays a decisive role in the treatment effectiveness of a wide range of chronic diseases; nonetheless, evidence is still lacking regarding periodontitis. The aim of the present pre-post quasi-experimental study was to evaluate the change in the Brief-IPQ before and after non-surgical periodontal treatment (NST) and to evaluate its ability to foresee the efficacy of NST.

A total of 126 periodontitis participants starting NST were asked to participate in the study. The nine-item Brief-IPQ together with a full periodontal chart were recorded at baseline and at the 3-month follow up (reevaluation) after NST. Pre-post comparisons of psychometric and periodontal variables were carried out through the Wilcoxon signed-rank test (α = 0.05). A predictive model was built to test the ability of the Brief-IPQ items to foresee the efficacy of NST.

NST led to a significant reduction in all periodontal parameters (P < 0.001); the proportion of pockets closed was 64.18%. Although the overall sum score of the Brief-IPQ remained fairly stable (P = 0.0673), significant changes occurred for items seven ("understanding") (P < 0.001) and 8 ("emotional response") (P < 0.05). The best model (R²  = 0.068, F = 2.15, P = 0.033) obtained from the multivariate linear regression analysis demonstrated that item five ("identity") (β = 2.340, P = 0.017) and item eight ("emotional response") (β = -2.569, P = 0.008) significantly predict the efficacy of NST (i.e., the proportion of pockets closed at reevaluation).

NST significantly ameliorates patient's understanding and emotional burden related to periodontitis. Baseline values of perceived symptoms and emotional response are predictive for the short-term efficacy of NST.