Private Practice Lugano, Mandibular repositioning in adult patients with class II and asymmetry. A two year folllow up. 2013 AAO Annual Session May 3-7, 2013 Philadelphia, PA Philadelphia Convention Center Giorgio Fiorelli Paola Merlo Birte Melsen University of Siena, Italy Private Practice Lugano, Switzerland University of Aarhus, Denmark

Abstract AIM. To verify stability and articular adaptation in adult patients where a mandibular repositioning of habitual occlusion (MR) was done before orthodontic treatment. METHOD. In 32 patients, with sagittal and/or transversal discrepancies, MR was performed before the orthodontic treatment by means of a composite built-up of posterior teeth. The maximum MR was 3.5 mm sagittal and 2.5mm transversally. Following the MR the Patients who showed occlusal stability and no muscular or TMJ symptoms after three months, were stabilized in the new mandibular position by orthodontic treatment. Two years after MR, the skeletal changes were assessed cephalometrically and the condylar position was analyzed by CBCT. RESULTS. 22 patients out of 32 showed immediate adaptation to MR with no muscular or TMJ symptoms. In 16 of these it was possible to evaluate stability two years later. Occlusal stability was found in 13 patients, a partial relapse in 3 patients. CONCLUSIONS. MR can be an alternative to camouflage or surgery, in adult patients with minor skeletal discrepancies.

The Aim was to asses if mandibular repositioning by condylar advancement can be used to treat malocclusions (class II or asymmetries) in adult patients with skeletal discrepancy and no TMD.

Which position for the condyle? DOWNWARD AND FORWARD ON THE POSTERIOR SLOPES OF THE ARTICULAR EMINENCES (Gelb) RETRUDED POSITION Needs a retrusive force and a loose or elongated temporo-mandibular ligament (inner part) OPTIMUM ORTHOPEDICALLY STABLE JOINT POSITION (Okeson) Most superoanterior position in the articular fossae, fully seated and resting against the posterior slopes of the articular eminences. Musculoskeletally the most stable position of the joint

The anterior limit for the condyle position was the middle of the posterior slope of the eminence as seen on a CBCT image . Maintaning this limit, condyles can be often displaced anteriorly 3 to 4 mm with respect to their original position in maximum intercuspation.

Occlusally bonded composite was used to establish a new occlusion and a mandibular repositioning in maximum intercuspation TRIAD GEL™ from Dentsply Full occlusal contact are provided by the use of Triad Gel™. This material is usually bonded in the lower arch buccal cusps, thus providing also laterotrusive group guidance.

Protocol 33 consecutive adult patients were repositioned using Triad Gel VLC or Triad VLC, before any orthodontic treatment, with one case exception due to the severe deep bite Maximum MR was 4 mm sagittal and 3 mm transversally. Changes in the condylar region and possible symptoms were assesssed over three months. If no changes were observed, no TMJ symptom and no muscular discomfort occurred, orthodontics was applied in order to establish a good occlusion with the mandible repositioned. 23 patients out of 33 were permanently repositioned (70%) At this time 16 patients have been evaluated for stability two years following repositioning.

Evaluation after 90 days Immediate Stability defined as : Okeson Abscence of disconfort, only need for minor repair of the Triad onlay . No sign on Palpation of TMJ, masseter and temporalis muscles Test for Inferior Lateral Pterygoyd for contraction fatigue: negative Okeson

Evaluation two years after MR (Long term stability) In patients with immediate stability an occlusion with the mandible in the new position was established by orthodontic and sometimes supplemented by prosthetics. None of these patients showed TMD in the following two years. Two years after, MR long term stability was evaluated by lateral or postero-anterior cephalometric analisys. In most cases condylar position was also evaluated on CBCT images . At this time not all orthodontic treatments were completed, however a good posterior occlusion was well established in all cases. Evaluation of transversal stability (asymmetry correction) Pre Treatment Immediate MR Two years after MR Transversal stability was evaluated using the angle between the facial symmetry line and the line ANS-Me

Results 23 patients out of 33 showed immediate adaptation to MR with no muscular or TMJ symptoms. In 16 of these it was possible to evaluate stability two years later. Occlusal complete stability was found in 13 patients (almost 80%), a partial relapse in 3 patients.

2 years follow-up group NAME Gender Birth Repositioning relapse (%) 1 PL M 1976 protrusive 4mm 0 2 NE F 1994 lateral shift 2mm 0 3 GS M 1972 lateral shift 3mm 0 4 CT M 1982 protrusive 3mm 0 5 CG F 1990 protrusive 3mm 50 6 PR M 1989 lateral shift 3mm 0 7 CM F 1994 lateral shift 2mm 25 8 ML M 1984 lateral shift 3mm 0 9 PG F 1995 lateral shift 2mm 0 10 AR F 1973 protrusive 3mm 0 11 PD M 1987 lateral shift 4mm 0 12 VT F 1992 protrusive 3mm 0 13 BM F 1963 protrusive 4mm 0 14 AA M 1966 protrusive 4mm 25 15 GR F 1959 lateral shift 3mm 0 16 TM F 1967 lateral shift 3mm 0

PL Class II correction, age 34 at MR Pre treatment The condylar was maintained in an extremely anterior position two years after MR. No TMD sign, no clinical dual bite Two years following repositioning Pre treatment Immediate MR 2y after MR Sagittal stability was evaluated using the angle FH – NPg

GS, symmetry correction, age 38 at MR Pre Treatment Pre treatment Immediate MR 3y after MR Immediate MR – Start Orthodontic Tr. At this time occlusion was stable, with no TMJ disorders or clinical dual bite. A possible osteogenesis can be seen on the posterior wall of the articular fossa. 3 years after MR and treatment start

Condylar Cbtc Evaluation Immediate MR Two years after MR The CBCT images demonstrated concistency between condylar position and cephalometric variables. In this case (correction of a left lateral deviation), the left condyle showed two years after MR a further anterior displacement, leading to further improvement of skeletal symmetry obtained with orthodontic treatment after initial MR.

Conclusions Mandibular repositioning, by anterior displacement of one or both condyles seems an acceptable procedure for the correction of moderate asymmetries and class II skeletal discrepancies in adult patients with no TMD. Of the patients studied 70% demonstraded an immediate adaptation to the modified mandibular position, of these 80% showed excellent long term stability (2 years), while a partial relapse was observed in the others. None of these patients showed TMD signs. Relapse was ascribed to lack of neuro-muscular adaptation, and insufficient preparation of natural dentition with orthodontic treatment in order to stabilize the modified abitual occlusion. Further long-term studies are needed to confirm the results, and to evaluate the adaptations of TMJ and muscles to an anterior repositioning of the mandible in adult patients.