Orthopedic treatment of dento-skeletal Class IIs has long been a source of controversy.

Some authors defend the purely skeletal action of activators while others advocate only dentoalveolar measures. A third group of authors are in favor of joint action, both skeletal and dentoalveolar.

The aim of this study is to demonstrate the efficacy of rigid monoblock activators combined with extraoral force for the potentialization of mandibular growth and for inhibition of maxillary growth.

Most studies into Class II activators have been conducted with the classical Steiner analysis using the Na, A and B points and angles SNA, SNB and ANB.

These studies have proven no selective action on the part of the various appliances since they do not distinguish between the different activator targets, namely, bone, alveolus and tooth.

In this study, two samples of treated patient are compared with a control sample using Delaire architectural, skeletal and dentoalveolar analysis. t-tests demonstrated the efficacy of the Lautrou rigid monoblock activator in slowing maxillary growth and in lengthening the mandibular corpus and rami (p<0.05).

Regarding dentoalveolar action, we noted no alveolar impact in the sagittal dimension in the upper arch. However, the activator prevented deterioration of lower alveolar retrusions and proved effective in treating overerupted incisors and reducing deep overbites.

As for dental effects, upper incisor palatal tipping was inevitable.