The effects of maxillary protraction and its long-term stability--a clinical trial in Chinese adolescents
| Autor: | Guo-Ping Ji, Gang Shen, Lin-ling Chen, Rong-Jing Chen, Yi-Ming Yang |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Male
China Palatal Expansion Technique medicine.medical_specialty Dentition Mixed Adolescent Rotation Cephalometry Dentistry Orthodontics Maxillary protraction Mandible Mandibular growth Maxilla Extraoral Traction Appliances Humans Orthodontic Appliance Design Medicine Nasal Bone Child Maxillofacial Development Dentition business.industry Puberty Vertical Dimension Sagittal plane Dentition Permanent Clinical trial Malocclusion Angle Class III Treatment Outcome medicine.anatomical_structure Orthopedic surgery Female business Follow-Up Studies |
| Zdroj: | The European Journal of Orthodontics. 34:88-95 |
| ISSN: | 1460-2210 0141-5387 |
| Popis: | The purpose of this study was to evaluate the effect of reverse pull headgear (RPHG) in the treatment of Class III malocclusions in the late mixed and early permanent dentition and its long-term stability at the time when facial growth was close to completion. The treatment group comprised 22 subjects (12 males and 10 females, mean age: 11.38 ± 0.69 years). The control group included 17 subjects (7 males and 10 females, mean age: 11.54 ± 1.07 years). The mean RPHG treatment time was 1.5 ± 0.95 years and the observation time for the control group was 1.75 ± 0.83 years. For each subject, lateral cephalograms were obtained before (T1) and after (T2) treatment or observation. These cephalograms were traced and analyzed and the differences between T1 and T2 values were examined with paired t-tests. Of the 22 treated cases, 10 patients were followed up until at the mean age of 16.18 years (T3). Since there was no relapse in anterior crossbite, the long-term effects of RPHG were evaluated by measuring the maxillary and mandibular skeletal changes. The follow-up patients were divided into two groups based on the change in ANB: a stable group (decrease in ANB2 degrees) and an unstable group (decrease in ANB2 degrees). The skeletal effects of RPHG in treating Class III anomalies just before or at the beginning of the pubertal growth spurt include protraction of the maxilla and dentition and inhibition of forward growth of the mandible. With regard to the long-term change, a slight alteration in the position of the maxilla and in the position and growth direction of the mandible resulted in a slight decrease in ANB in the stable group. The slight retrusion in the maxilla, combined with the significant protrusion in the mandible and the more horizontal mandibular growth direction, resulted in a decrease in ANB in the unstable group. This indicated that the maxilla remained relatively stable and that the unstable factor was continuing mandibular growth during the pubertal and post-pubertal period. For patients with an excessive mandible, orthopaedic therapy should start at the beginning of pubertal growth and orthodontic fixed appliance should follow immediately after RPHG so that mandibular growth in the sagittal direction during puberty or even after pubertal growth may be effectively inhibited. |
| Databáze: | OpenAIRE |
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