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The Pendulum Appliance Indications and Clinical Management Doz. Friedrich K. Byloff Graz, Austria Some important aspects in constructing the Pendulum Appliance are outlined as follows: • The coil springs are made of .032 TMA wire (Ormco). • The P.A. is bonded either to the upper bicuspids or to the primary molars (Fig. 1,2,4) by means of auxiliary 0.32 inch TMA or stainless-steel wires using composite resin and avoiding occlusal interferences. They can approach the tooth from the distal or the mesial (Fig. 1,2,4). • An expansion screw is incorporated, only if necessary, to correct arch width discrepancies (Fig. 1). • The acrylic Nance portion should not touch the incisors and should not reach too far distal to the coil spring, as intraoral insertion might be difficult (Fig. 1,2,4). • A perfect fit of the acrylic on the palatal mucosa should be achieved during bonding of the P.A. (Fig. 1,2,4). • The palatal sheaths on the molars, made by GAC should have an 8° angulation as this facilitates intraoral insertion (Fig. 11). • The plane of the coil springs should be parallel to the maxillary plane (or occlusal plane / Fig. 3). • Initial activation should not exceed 250 grams with the arms bent back at about 45° (already prepared by the lab-technician / Fig. 2). • It is important to note that the part of the spring inserted into the lingual sheath is recurved for better control of distal movement and vertical dimension. Note that the second part of the recurved end is shorter than the first one to provide for better intraoral grip with a weingart plier during reactivation and uprighting (Fig. 5,6,7,8). Some important aspects in activating and reactivating the Pendulum Appliance are outlined as follows: • We reactivate intraorally, if necessary after 2 - 3 months! (Fig. 11) • First the molar(s) should be distalised into an overcorrected Class I relation (if one is correcting a Class II). This can take up to 4 months. • Uprighting is accomplished using an „uprighting bend“ of 10° to 15° which is introduced intraorally with a weingart plier (as seen on models in Fig. 5,6,7,8). Please note that reinsertion might be somewhat tricky and the appliance will usually stay in place 2 - 3 months until the molar is sufficiently uprighted. • As already mentioned, the expansion screw is used only if needed. Activation is usually one turn every 3 days until the necessary expansion is obtained. Some important aspects in removing the Pendulum Appliance are outlined as follows: • The same day the P.A. is removed a Nance arch (Fig. 9) should be inserted. This is left in place for several months. Here again perfect fit of the acrylic part of the Nance appliance on the palatal mucosa is recommended (Fig. 10). It is also recommended that the Nance arch be soldered to the upper molar bands (Fig. 9,12). • After ca. 3 - 4 months, fixed appliances are used as the last step in treatment (Fig. 12). Some important „tips and tricks“ when using the Pendulum Appliance are outlined as follows: • Sometimes brackets are bonded as early as possible in the lower arch to allow the earliest insertion of a solid arch which can be used as anchorage when using Class II elastics. Such elastics may be necessary as light support when distalising the upper dentition. • We leave the Nance arch in place during the levelling phase and then cut it off. It is for this reason that the molar must already be perfectly uprighted by the P.A. (Fig. 12). • Anchorage preservation is essential throughout the time with braces. This is of the utmost importance as molars tend to move forward again. • We almost never use Headgears to support anchorage in finishing but, it is of course possible. Some important guidelines on how to choose the type of case which is most suited for the Pendulum Appliance: • Clinically we suggest to correct only cusp to cusp Class II relationships. We do not use the P.A. in full Class II cases nor skeletal Class II cases with significant overjet. • We have had good experience in Class III tendencies with upper arch crowding by using the P.A. for space creation. • The P.A. can be used unilaterally to correct unilateral Class II relationships by activating one side. • In young adults we sometimes extract second molars, distalise the first molar with the P.A. and then let the third molar erupt into the space left by the extracted second molar. Finally: It is important to remember that during the P.A. phase there is a mesialisation of the premolars and incisors (ref. 2,3,4). These must subsequently be redistalised very carefully with fixed appliances. Anchorage preservation is of the utmost importance to prevent undesirable relapse. Literature on the P.A.: Hilgers JJ.: The Pendulum Appliance for Class II non-compliance therapy. J.Clin. Orthod. 1992; 16:706-14. Ghosh J., Nanda RS.: Evaluation of an intraoral maxillary molar distalisation technique. Am J. Orthod. Dentofac. Orthop. 1996; :639-46. Evaluation of an intraoral Maxillary molar distalization technique Ghosh J and Nanda RS AJODO 1996;110: 639 – 96 (december) Byloff F.K., Darendeliler M.A.: Distal molar movement using the Pendulum Appliance. Clinical and radiological evaluation: Part 1. Angle Orthod. 1997;67:249-60. Byloff F.K., Darenedliler M.A., Clar E., Darendeliler A.: Distal molar movement using the Pendulum Appliance. Part 2: The effects of maxillary molar root uprighting bends. Angle Orthod. 1997; 67:261-70. Dentoalveolar and skeletal changes associated with the pendulum appliance Bussick T Jand Mc Namara J A AJODO 2000;117:333-43 (march) Modified Pendulum Applince Including Distal Screw and Uprighting Activation for Non-Compliance Therapy of Class II Malocclusion in Children and Adolescents G.Kinzinger, R. Fuhrmann, U. Gross, P. Dietrich, et al. J Orofac Orthop 2000;61:175-90 Effects of the Pendulum Appliance on the Dentofacial Complex Jose Chaques-Asensi, Varum Klara J. Clin. Orthd. 35: 254-257, 2001 Maxillary molar distalization or mandibular enhancement: A cephalometric comparison of comprehensive orthodontic treatment including the pendulum and the Herbst appliances D. R. Burkhardt, J. A.Mc Namara and T. Baccetti AJODO 2003 ;123:108-1 Molar Distalization with Different Pendulum Appliances: In Vitro Registration of Orthodontic Forces and Moments in the Initial Phase G.Kinzinger, C.Syree, U. Fritz, P. Diedrich, et al. J Orofac Orthop 2004;65:389-409 Molar Distalization with a Modified Appliance-In Vitro Analysis of the Force System and in Vivo Study in Children and Adolescents G. Kinzinger, H. Wehrbein, P. Dietrich Angle Orthod 2005;75:484-493 Anchorage quality of deciduous molars versus premolars for molar distalization with a pendulum appliance Kinzinger GSM, U. Gross, U. Fritz, P. Dietrich Am J Orthod Dentoacial Orthop 2005;127:314-23 Sagittal, vertical, and transverse changes consequent to maxillary molar distalization with the pendulum appliance Fuziy, R. Rodrigues de Almeida, G. Janson, F. Angelieri, and Pinzan AJODO 2006 ; 130 :502-10 Dentoalveolar and skeletal changes associated with the pendulum appliance Followed by fixed orthodontic treatment F.Angelieri, R. Rodrigues de Almeida, M. Rodrigues de Almeida, and A Fuziy Am J Orthod Dentofacial Orthop2006;129:520-7 Cervical headgear vs pendulum appliance for the treatment of moderate skeletal Class II malocclusion Claude F.Mossaz, Friedrich K.Byloff, and Stavros Kiliaridis Am J Orthod Dentofacia lOrthop 2007;132:616-23 Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 Fig 6 Fig 7 Fig 8 Fig 9 Fig 10 Fig 11 Fig 12 not correct correct not correct correct www.bycla.at [email protected] www.byloff.com