MOLAR DISTALIZATION WITH MODIFIED GRAZ IMPLANT SUPPORTED PENDULUM SPRINGS. A CASE REPORT.

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1 MOLAR DISTALIZATION WITH MODIFIED GRAZ IMPLANT SUPPORTED PENDULUM SPRINGS. A CASE REPORT. Author : Dr. Arundhati P. Tandur MDS, MDORCPS [Glasgow], IMORTHRCS [England], Diplomate of Indian Board Vice-Principal Professor and Head of the Department of Orthodontics at K.L.E Society s Institute of Dental Sciences, Bangalore, Karnataka , India. aptandur@hotmail.com Abstract Key words Based on the philosophy of the Graz implant-supported device, modified implant supported pendulum appliance is presented. It is designed to distalize the maxillary first molars in a 13year old patient. It consists of two parts: mini-implant fixed to the palatal bone and stainless steel cast crown to which pendulum springs are attached. A finished clinical case is shown. The system can be loaded immediately and it actively distalizes maxillary molars without any reciprocal effect on maxillary anteriors. Graz implant, Pendulum springs, Maxillary molar distalization. Introduction: Orthodontic miniscrews have gained popularity in recent years because of their versatility, minimal invasiveness, and low cost. 1-2 Several appliances with different implant methods have been proposed to gain space by means of molar distalization in the maxillary arch. 3 Palatal implant for distalization of molars can be used by two methods: I] It can be directly connected to the teeth that have to be moved by means of a distalizing device {direct method}, so that the reactionary forces are completely dissipated on the implant. II] It can be used as a reinforcement anchorage unit, by means of transpalatal bar connecting the first premolars and the implant; in this way the reactionary forces are dissipated on the dental/ implant unit {indirect method}. 3 This article describes modified Graz implant 4 used for distalization of maxillary molars which is a direct method to correct class II molar relationship. Case Report: Patient aged 13 years reported with the complaint of malaligned upper front teeth. She had bilateral class II molar relationship with slight amount of crowding in the upper arch. Her face was symmetrical from the front, straight profile, obtuse nasolabial angle, prominent nose and chin. In addition to the class II molar relationship she had an over jet of 4mm,an overbite of 3mm and 6mm of crowding in the maxillary arch. [Fig 1] Cephalometric data SNA 82º SNB 80º ANB 2º U1-SN 124º U1-NA 41º, 6mm L1-NB 26º, 4mm AO-BO 0mm FMA 20º IMPA 100º SN-GOGn 25º MMPA 27º Naso-Labial angle 100º E Line- U= -2mm L= -1mm Treatment plan As this patient had a good profile, skeletal class I and average growth pattern, [Fig 2] non-extraction treatment 15

2 Pre-treatment Photographs (Fig. 1) Pre-treatment Radiographs (Fig. 2) 16

3 was planned. She had normal over jet and over bite with mild crowding in the upper arch. To correct class II molar relation and to relieve mild crowding, distalization procedure was planned. Treatment progress [Fig 3] MBT appliance was placed. After initial aligning and leveling, modified Graz implant was placed. In this method, midpalatal implant {Abso Anchor SH 7mm in length} was placed in para-median region. Silicon impression was made after placement of the implant. On this impression of implant, stainless steel cast crown was fabricated. To this crown, abutment tubes that had a diameter were soldered. Stainless steel crown is cemented on to the implant. [Fig 3]The pendulum springs made of beta-titanium wires were made and inserted in the casting crown tubes. [Fig 4] After cementation of stainless steel cast along with pendulum springs, activation of the springs was carried out immediately. Graz implant is osseointegrated 4, but this modified Graz implant is not osseo integrated. It was loaded immediately after placement of the implant. During distalization, the springs were activated every 4 to 6 weeks. After sufficient space was gained, the implant was removed. [Fig 5] Cephalometric data SNA 82º SNB 80º ANB 2º U1-SN 115º U1-NA L1-NB AO-BO 27º, 4mm 26º, 4mm 0mm FMA 20º IMPA 102º SN-GOGn 25º MMPA 27º Naso-Labial angle 100º E Line- U= -2mm L= -1mm Discussion In conventional approach, extra oral appliances are used for molar distalization. But co-operation of patient is uncertain. Although intraoral distalization appliance have high acceptance by patients, they still require compliance. Side effects on other maxillary and mandibular teeth, the force exertion capacity, breakage and the need for frequent reactivation are other disadvantages of these appliances. To reduce the side effects of distalization, modified Graz implant procedure was carried out. The main advantages of the modified Graz implant supported pendulum are its stability against rotational movements and the possibility of immediate force application. The disadvantage is a surgical intervention for insertion and removal of implant and laboratory procedure for fabrication of the cast crown. Superimposition reveals good profile improvement, no opening of mandibular plane angle and molar distalization without moving upper anteriors in forward direction. [Fig 10] Conclusion In conventional orthodontic therapy for class II malocclusion, it might be necessary to use a distalizing appliance or extract four premolars to correct the molar relationship. However, the anchorage potential of intraoral distalizing appliances is somewhat inadequate, and side effects are likely. Since the introduction of implants as anchorage units for orthodontic appliances, promising results have been reported. Therefore, rather than relying on conventional treatment mechanics, an implant was preferred as an anchorage unit for this patient. This appliance system provided absolute anchorage for molar distalization. References 1. Costa, A.; Raffaini, M.; and Melsen, B.; Miniscrews as orthodontic anchorage: A preliminary report, Int.J.Adult Orthod.Orthog.Surg1998; 13: Kanomi, R.:Mini-implant for orthodontic anchorage, J.Clin.Orthod1997; 31: MoschosA.Papadopoulos.; Orthodontic treatment of the classii noncompliant patient: Current principles and techniques,ed,mosby,elsevier, Friedrich K.Byloff.; Hans Karcher.; Ernst Clar.; and Franz Stoff.; An implant to eliminate anchorage loss during molar distalization case report involving the Graz implant-supported pendulum, Int J Adult Orthod Orthognathic Surg2000;15:

4 (Fig. 3) Surgical guide Before marking Placement of implant With implant Impression of Implant Stainless steel cast on Implant Fig. 4 Pendulum springs inserted into tube Fig. 5 After molar distalization Post-distalization OPG 18

5 Fig. 6 After Aligning and Levelling During settling (Fig. 7) Pre-finishing Radiographs (Fig. 8) 19

6 Post-treatment photographs (Fig. 9) 20

7 Superimposition (Fig. 10) 21