what do prospective randomized clinical trials tell us about the treatment of class II malocclusions?
The prospective randomized clinical trial (RCT) is seen by many to be the ‘gold standard’ for analysing treatment outcome and the only valid source of clinical data. In orthodontics, most RCTs have been designed to resolve the controversy surrounding the ability of functional appliances to significantly modify dentofacial growth. Given the variability in the timing, magnitude and duration of pubertal dentofacial growth, differing levels of motivation and patient compliance, the inherent inaccuracy of cephalometry and the questionable validity of the measurements themselves used to quantitate change, it is not surprising that the conclusions have not been as clear-cut as anticipated. Unlike a laboratory experiment, in which it is possible to limit the differences between experimental and control groups to the single factor being investigated, in a clinical trial an orthodontic appliance is just one of several variables affecting the outcome. Furthermore, RCTs are expensive and time-cons
