AIM:
There has been growing interest in motivational interviewing (MI) as a structured method for supporting health behaviour change in periodontal therapy. The aim of this study was to investigate the influence of communication techniques used in MI on statements of patients undergoing periodontal therapy.

MATERIALS AND METHODS:
Thirty audio-recorded sessions between dental MI providers and their patients undergoing periodontal therapy were coded using the German version of the Motivational Interviewing Sequential Code for Observing Process Exchanges (MISCOPE; D). Sequential analyses were performed to access transition probabilities among certain counsellor and patient statements.

RESULTS:
MI-consistent counsellor statements were statistically significantly positive correlated with patients' language in favour of change (change talk) (OR = 1.31; p = 0.027). MI-inconsistent statements were statistically significantly more likely to be followed by patients' language against change (sustain talk) (OR = 2.27, p = 0.002). An additional sequential analysis revealed significant correlations between certain evocative counsellor behaviours and the language of their patients.

CONCLUSION:
Specific verbal expressions described in the theory of MI significantly influence the subsequent statements of the patient in periodontal therapy. Accordingly, the periodontist can guide patient communication in a desired direction, evoke motivational statements and reduce expressions of resistance.