We used strain gauges on a dried adult human skull to measure the effect of headgears on the force system of multi bracket appliances. The face bow headgear produced distal movement in the maxillary dental arch by rotation centered in the region between the apices of the first premolar and canine, as well as enlargement of the dental arch. The J-hook headgear produced the greatest compressive strain when force was applied to hooks placed between the maxillary lateral incisors and canine. These results suggest that the headgear is an effective auxiliary to multi bracket appliances.