A cephalometric evaluation of pretreatment and post-treatment outcome using Tetragon analysis: a retrospective study

Few cephalometric analyses have been put forward to assess the treatment outcome after orthodontic treatment. However, these analyses are somewhat complicated and time consuming. The Tetragon analysis is introduced with measurement of treatment outcome as one of its objectives.

The study was undertaken to evaluate the treatment outcome by checking the skeletal and dental changes using pretreatment and post-treatment radiographs and to evaluate the efficiency of treatment in the Department of Orthodontics, College of Dental Sciences, Davangere, using the Tetragon analysis.

Records of 35 finished patients with fixed orthodontic therapy using preadjusted edgewise appliance were selected. The samples were analyzed separately for the skeletal parameters consisting of skeletal class I, II and III using Tetragon analysis.

The post-treatment reduction of upper incisor palatal plane angle was found to be statistically significant in skeletal class I (p < 0.01) and skeletal class II patients (p < 0.05). The post-treatment increase in interincisal angle was found to be statistically significant in skeletal class I (p < 0.01) class II patients (p < 0.05).

Fixed appliance therapy reduced the proclination of upper incisors and increased the interincisal angle in skeletal class I and II cases but not in skeletal class III cases. The lower incisal angulation and the maxilla-mandibular plane angle did change significantly and so were the angles of the Trigon. The Tetragon analysis proved easy to measure the treatment outcome.