[Cast analysis of 37 patients treated with MBT(TM) appliance].

OBJECTIVE: To study the 3D positional changes occurring to anchor molars of 37 patients treated with MBT appliance. METHODS: Thirty-seven patients who needed maximum upper molar anchorage were divided into two treatment groups at random, group I was comprised of 19 patients whose anterior teeth were retracted en masse, and group II included 18 patients whose anterior teeth were retracted by two step. All the patients were treated with MBT appliance and headgear. Dental casts recorded before and after treatment were analyzed by YM-2115 three-dimensional digitizer and related software. The changes of anchor molar tip,torque and rotation were compared between the two groups. RESULTS: During the treatment, average anterior movement of the upper first molars was 4.53 mm, average extrusion of the upper first molars was 1.53 mm; the crown of the upper first molar tipped forward (6+/-4) degrees,torque buccally (3+/-6) degrees,and mesiolingually rotated 3.15 degrees; In en mass group, the crown of the upper first molar tipped more mesially than the two-step group, and the difference was statistically significant. CONCLUSION: Almost all the upper first molars showed the tendency to rotate and tip mesially and torque bucally; there was no statistically significant difference between the two treatment groups when upper molar positional changes were concerned except for the mesial tip of the crown.

[The effect of pre-surgical orthodontics on secondary alveolar bone grafting in the patients with complete cleft lip and palate].

OBJECTIVE: To examine the effect of pre-surgical orthodontics on the outcome of the secondary alveolar bone grafting in the patients with complete cleft lip and palate. METHODS: Sixteen complete cleft lip and palate patients (9 males and 7 females) with collapsed upper arch or severe mal-positioned upper incisors were selected. The cleft was not easily grafted because of the poor access. The total cleft sites were 22 (10 patients with UCLP and 6 patients with BCLP). The age range of the patients was from 8 to 22 years. Pre-surgical orthodontic treatment was mainly to expand the collapsed upper arch and correct the mal-positioned upper incisors. After the secondary alveolar bone grafting, the patients were followed up and anterior occlusal radiograph/intraoral panograph were taken regularly. The observation period was from 6 months to 4 years. Bergland criteria were used to evaluate the interdental septal height. RESULTS: Upper arch expansion and the correction of the mal-positioned upper incisors done by the orthodontic treatment made the bone grafting procedure easier. The clinically successful rate reached 86%. CONCLUSION: The severe upper arch collapse and mal-positioned upper incisors in the patients with complete cleft lip and palate should be corrected orthodontically before the secondary alveolar bone grafting.