title: Use of analysis of covariance in periodontal clinical trials.
mesh_terms: D000704:Analysis of Variance; D003728:Dental Calculus / Q000175:diagnosis / Q000517:prevention & control; D003773:Dental Plaque / Q000175:diagnosis / Q000517:prevention & control; D005500:Follow-Up Studies; D005891:Gingivitis / Q000175:diagnosis / Q000517:prevention & control; D006801:Humans; D010512:Periodontal Index; D012008:Recurrence