Trial design {8}
gingivitis
GINGIVITIS
The design of this randomized clinical trial is a “waiting control group design”, which compares the immediate intervention group with the delayed intervention group. The latter one will serve as a control group. The intervention cannot be blinded, but the outcome measure (lung function tests) is blinded, because the technician does not know to which group (immediate or delayed intervention) the subject belongs to. Moreover, the absence of any intervention in subjects with gingivitis would be unethical, but an intervention delayed for 4 weeks seems acceptable.