ABSTRACT
<p><b>OBJECTIVE</b>This study aims to compare the changes of hyoid bone position before and after treatment of Angle class Ⅲ malocclusion using improved appliance FR Ⅲ.</p><p><b>METHODS</b>Forty patients with Angle class Ⅲ malocclusion were chosen and divided into two groups, namely, experimental and control. Each group had 20 patients. The young patients in the experi-mental group were treated using improved appliance FR Ⅲ, whereas those in the control group were treated using classic appliance FR Ⅲ. The hyoid bone position of the two groups were comparatively analyzed using an X-ray film before and after treatment.</p><p><b>RESULTS</b>Compared with the condition before treatment, the condition after treatment showed that the hyoid bone position of young patients with Angle class Ⅲ malocclusion treated using improved appliance FR Ⅲ, H-FH, H-S, H-Ptm, and Ar-H-Me exhibited an increased angle (P<0.01), whereas the hyoid bone position of those treated using H-MP and H-Gn showed a decreased angle (P<0.01). The hyoid bone position of young patients with Angle class Ⅲ malocclusion treated using classic appliance FR Ⅲ, H-FH, H-S, and H-Ptm had an increased angle (P<0.05). Moreover, the hyoid bone position of those treated using Ar-H-Me had an increased angle (P<0.01), and the hyoid bone position of those treated using H-MP and H-RGn had a decreased angle (P<0.05).</p><p><b>CONCLUSIONS</b>Compared with the hyoid bone position before treatment, the hyoid bone position after treatment of the young patients with Angle class Ⅲ malocclusion treated using improved appliance FR Ⅲ may move backward and downward, and the mandibular and hyoid bone position may move through clockwise rotation. The mandibular and hyoid bone position of young patients with Angle class Ⅲ malocclusion treated using classic appliance FR Ⅲ obtained a large angle by moving clockwise. The man-dibular bone moves backward and downward, thereby improving the hyoid bone in backward and upward directions. This condition makes a significant difference in treating the hyoid bone position of young patients with functional Angle class Ⅲ malocclusion. .</p>
Subject(s)
Humans , Hyoid Bone , Malocclusion, Angle Class III , MandibleABSTRACT
[Objectives]This study was designed to evaluate the treatment effects of a new movable molardistalization appliance for distal movement of maxillary first molars on Angle's Class Ⅲ malocclusion adolescence patients with the second premolar crowded.[Methods]Sixteen patients were treated by a new movable molardistalization appliance.Cephalometric analysis and model measurement was carried out before and after the treatment.Data were analyzed by paired t-test.[Results]The molars were distalized 5 mm during an average time of 3.8 months.There were significant increases in the Angle SNA and A-NPg(P ＜0.05).[Conclusion]it was a effective way to get space and improve patient's profiles on Angle's Class Ⅲ malocclusion adolescence patients with the second premolar crowded by the new movable molardistalization appliance.It was also conducive to patient's oral hygiene.
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Objectives To study the changes of hard tissue before and after orthodontic treatment for Angle's class Ⅲ malocclusion adolescence patient with maxillary front traction. Methods 20 cases of Angle's class Ⅲ malocclusion adolescence patients were treated by front traction in maxilla, while there were 20 cases of Angle's class Ⅰ malocclusion adolescence patients as the control group. Cephalometric a-nalysis was carried out before and after the treatment. Data were analyzed by SPSS11.0 system using paired t-test. Results There were significant increases in the length, anteroposterior diameter and thick-ness of maxillary sinus (P<0.05), while there was no significant differences in the site and central point of maxillary sinus(P>0.05). Conclusions It is a effective approach to change the hard tissue after ortho-dontic treatment for Angle's class Ⅲ malocclusion adolescence patient with front traction in maxillary area.
ABSTRACT
Objective: To study the effective initiating time of the maxillary protraction therapy for the children with skeletal classⅢ malocclusion. Methods: 20 cases with class Ⅲ malocclusion were divided into 2 groups: older group (9～ 12 years old) and younger group(5～8 years old), and treated with maxillary protraction. Before and after treatment cephalometric radiographs were taken and analyzed. Results: Good effects were found in both groups. The treatment in the younger patients showed the advantages of shorter treatment period, more skeletal changes, less dental changes and less side effects. Conclusion: Earlier maxillary protraction is more beneficial to the children with Angle Ⅲ malocclusion.