The evaluation of alveolar bone thickness changes with computed tomography resulted from protraction of maxillary anterior teeth with two different methods

The aim of this study is to evaluate the affect of face mask and 2×4 utility protrusion arch on the thickness of alveolar bone, on the maxillary anterior incisors region at Class III patients characterized by mild maxillary retrognatia, anterior crossbite, whose maxillary incisors didn?t placed further than the alveolar bone and who is at the pubertal maturation.Our research was performed with 17 boys and 13 girls, as a sum of 30 individuals. Attention was paid to all individuals that they are on the pubertal maturation period, have Class III malocclusion characterized by anterior crossbite and mild maxillary retrognatia and have not maxillary incisors further than the alveolar bone. 15 patients (5 girls, 10 boys) that form first group were treated with face mask while 15 patients (8 girls, 7 boys) that form second group were treated with 2×4 utility protrusion arch. In both treatment groups, computed tomography(CT) scans were taken additional to lateral cephalometric radiographs at the beginning of the treatment and 3 months after finishing the protrusion of maxillary incisors for each of 30 patients. Measurements of CT were done at three sites as cervical level, middle third root level and apical level at the beginning of the treatment and 3 months after finishing the protrusion of maxillary incisors for each group.At he end of our study, maxillary incisors exhibit significant protrusion and the overjet exhibits significant increase at each of groups. Labial alveolar bone thickness was significantly decreased 3 months after the protrusion of maxillary incisors at the face mask group. Some of the labial alveolar bone thickness values were significantly decreased at the 2×4 protrusion arch group. Palatal alveolar bone thickness was significantly decreased 3 months after the protrusion of maxillary incisors at the both of treatment goups.Both of the treatment type were effective on the correction of abnormalities with the dental changes that they caused on the treatment of patients with Class III malocclusion characterized with anterior crossbite, mild maxillary retrognatia that doesn?t need eccessive skeletal correction and who is at the pubertal growth and development stage. But about differences that ocur on the alveolar bone, 2×4 protrusion arch has few advantages than face mask in terms of allowing equalization of apositioning activity with resorption activity at the direction of teeth movement.Key Words: face mask, 2×4 utility protrusion arch, alveolar bone thickness, resorption, aposition, computed tomography, Class III malocclusion.