The time of correction of a cross bite was from 2-12 months which is considered as a short amount of time. This can be attributed to adaptation of the appliance together with its variable sizes which helps with each individual case, also the ease of calibration of the force which if exceeded may be destructive and dangerous to the newly erupted upper incisors. This is not in agree-ment with the result of Kanno el al (2007) 13 who found that good incisal relationship was achieved and facial esthetics were greatly improved after 28 months which is a longer time period than our study’s but in his study a monoblock appliance was used. The selection of the patient in the mixed dentition will help to achieve good results as indicated by our research totals which showed 40 % correction after 4 months with the appliance. Since this is an active period for growth and development of the bone and teeth which is in accordance with the result of Kim et al (1999) 3 who indicated that protractive face mask therapy is effective in patients who are growing but to a lesser degree in patients who are older than 10 years of age. Successful treatment of these conditions is firmly related to early interceptive treatment and is often associated with tooth-size/arch-size discrepancies. In many respects, this is contrary to the present philoso-phy of a regimen for orthodontic practice based on treatment in the permanent dentition. 4 Based on histologic studies, the prognosis for treatment of labial segment crowding is better in mixed dentition than in permanent dentition. Melsen carried out an investiga-tion to determine the histologic effect of rapid expan-sion of the midpalatal suture in children of various ages. A true stimulation of sutural growth was found only in children who had not attained maximum pubertal growth. 15 The use of ANB angle for cephalometric measure-ments is worthy as it is one of the most popular measurements for assessing antero-posterior dysplasia in cephalometric analysis. 16, 17, 18 There were no other studies related to Transforce arch developers so we tried to correlate our results with other more closer methods like using face mask which enhance the treatment as mentioned by Godet et al (2008) 19 who compared two treatment strategies. The first group included removable func-tional orthopedic appliances only (FOA group), while the second group was treated with removable appli-ances and with face masks mounted on a cemented maxillary expansion appliance (face mask group). And concluded that Early treatment of prognathism is a meaningful option, as demonstrated by the dentoskeletal (and hence functional) improvements observed in the present study. The use of arch devel-oper with chin cap as used in the present study may be substitute for face mask but it needs more studies conducted and more patients to be evaluated. The present study showed that the upper incisors proclined in a period ranging from 2-12 months. This 20 November/December 2011 JAOS
Journal of the American Orthodontic Society November-December 2011: Page 20
