Evaluation of orthodontic treatment in patients with extraction of mandible first molar using PAR index and cephalometrics

Abstract

Objective To access the clinical effect of orthodontic treatment in patients with extraction of mandible first molar. Methods Nineteen patients (three male and sixteen female) with extraction of mandible first molar be⁃ cause of caries, periapical disease were collected as experimental group. The age was 21.37 ± 5.07. Nineteen patients (seven male and twelve female) with extraction of four premolar as control group, The age was 20.42 ± 4.23. All the pa⁃ tients were treated with orthodontic space closure using MBT preadjusted appliance and sliding mechanics PAR index and cephalomertics that were compared before and after orthodontic treatment. Results The two groups􀆳 reduction in weighted PAR score and each of the PAR score differences were statistically significant (P＜0.01). There was no signifi⁃ cant difference between the two groups after treatment in PAR. There were significant changes in U1⁃NA (°)、U1⁃NA (mm)、U1⁃SN(°), but not in the rest of the value in experimental group (P＜0.01). The L1⁃NB(°)、L1⁃NB (mm) was sig⁃ nificant difference before and after treatment. Extraction spaces of mandible first molars were closed (P＜0.01); Good occlusal relationships and soft tissue profiles were achieved in all cases. Conclusion If the mandibular first molars have serious caries or periapical lesions, removal of mandibular first molar, making full use of the mandibular third mo⁃ lar and keeping health premolars for orthodontic treatment could receive satisfactory results.

Keywords

• PAR index
• Cephalometrics
• Mandible first molar
• Extraction
• Effect evaluation
• Orthodontic treatment