Long-term evaluation of the molar movements following Pendulum and fixed appliances

Abstract

Objective: To describe the molar movements and skeletal changes associated with Pendulumfixed 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. (Angle Orthod. 2013;83:447-454.)

Comparative evaluation of molar distalization therapy with erupted second molar: Segmented versus Quad Pendulum appliance

“…Most of the articles did not provide data relative to the second molar during the distalization phase, making difficult to compare our data with those from studies that use other appliances, in which the second molar was moved distally by a force acting on the first molar. However, during fixed appliance therapy (T2 to T3), the mesial movement of the maxillary molars was noted in both appliances, and distal tipping was completely corrected, but part of the distal movement (about 45%) was maintained at the end of the treatment (1.8 mm in the SP and 1.5 mm in the QP), confirming the findings previously reported in a long-term investigation using Pendulum appliance (57%) [26]. However, it can be noted that most of the class II correction can be achieved by a favorable mandibular growth in both groups (Figures 4 and 5).…”

“…The cephalometric analysis consisted of 32 landmarks, 13 angular measurements, and 15 linear measurements for each tracing; 4 fiducial markers were also placed in the maxilla and mandible [24] (Figure 3a,b,c). The 32 landmarks and the 4 fiducial markers were used for superimposition [25,26].

Figure 3 Cephalometric landmarks and measurements (a, b, c).

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Comparison between direct vs indirect anchorage in two miniscrew-supported distalizing devices

“…However, they presented two main negative effects: (1) anchorage loss in reaction to the molar distalization, 1 such as premolar mesial movement and flaring of the maxillary incisor, which could require additional time to be corrected during the fixed appliances therapy, and (2) the use of distalized molars as anchorage to retract anterior teeth, with the consequent high risk of relapse to the Class II molar relationship. 5 In order to increase anchorage resistance and avoid undesirable side effects on anchoring teeth, the use of mini-implants or miniscrews was introduced. 6 Based on their reduced invasiveness, ease of insertion and removal, the possibility of immediate loading, and their versatility, these devices were increasingly used, even in combination with distalizing devices.…”

Skeletal versus conventional intraoral anchorage for the treatment of class II malocclusion: dentoalveolar and skeletal effects

“…The Pendulum appliance was chosen for the control group because it is one of the most thoroughly investigated non-compliance distalizing appliances in the literature [3,4]. Maxillary molars in both groups were distalized successfully to class I relationships without patient cooperation.…”

“…Even though they are effective means of achieving tooth movement, all these treatments are highly dependent on patient compliance. Beginning in the 1990s, many treatment protocols have been suggested with a view to reduce this dependence on patient compliance [3,4]. …”