Objective:  

 To describe the molar movements and skeletal changes associated with Pendulum-fixed appliance treatment and the long-term postretention period.

 Subjects and Methods:  

 The treatment sample consisted of 76 Class II patients, 35 males and 41 females. Lateral cephalograms were obtained at the start of treatment (T1) the end of distalization (T2) the end of orthodontic fixed appliance therapy (T3) and long-term observation (7 years 2 months later T4). Mean age was 12 years 11 months at T1, 13 years 8 months at T2, 15 years 4 months at T3, and 22 years 5 months at T4. The average amount of Class II molar relationship was 3.1 mm, with a mean overjet of 5.9 mm at the beginning of treatment. A paired t-test was used to identify significant between-group differences between T2–T4 and T3–T4.

 Results:  

 Distal molar movement was obtained during the distalization phase (T2), and more than half of the distalizing effect was maintained at the end of maxillary growth (T4). Most of the relapse occurred during fixed appliance therapy (T3), whereas no significant change was detected in the postretention period (T4). The molar relationship did not show any significant difference between T2 and T4. The vertical facial dimension increased during the distalization phase (T2) and fixed appliance therapy (T3) but returned to the initial values during the postretention period (T4).

 Conclusions:  

 The Pendulum appliance induces significant dentoalveolar effects, which can be partially maintained during the long-term period. The Class I molar relationship does not change during completion of individual growth. Increase in vertical facial dimension represents a temporary effect.

 Source: The Angel Orthodontists

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