GAP Australasian-Dentist Issue 80 Jul-Aug 19

Category 88 AustrÀlÀsiÀn Dentist INTRODUCTION Destructive Àemporomandibular (ÀMJ) pathology can arise from arthritic degenerative joint disease 1 and idiopathic condylar resorption 2 resulting is severe class 2 skeletal base malocclusion and bird face deformity. Àevere mandibular retrognathia not only has a negative psychological impact on patients, but it can also compromise the airway leading to obstructive sleep apnoea 3 . Conventional treatment focuses on orthognathic surgery alone to correct the severe class 2 mandibular deficiency and ignores the temporomandibular joints. Àhis approach is appropriate if the ÀMJ’s are healthy. However, when the ÀMJ’s exhibit destructive pathology, due consideration must be given to performing the bimaxillary advancement surgery together with ÀMJ prosthetic total joint replacements which will provide a much more stable outcome. Àhe aim of this article is to present two case examples where combined orthognathic and ÀMJ prosthetic total joint replacement surgery was used to correct severe mandibular retrognathia in patients with concomitant destructive ÀMJ pathology. Case 1 A19yo femalewas referred to the author for correction of her severe class 2 mandibular retrognathia that became progressively worse since the age of 16 yr with increasing pain in both ÀMJ’s (figs. 1-3). Àerial x-rays over 4 years showed progressive resorption of the patient’s condylar heads so by the time she presented to the author, both the condyles were mere stumps (figs.4, 5). As a consequence of her class 2 retrognathia, she had also developed a vertical maxillary excess (VMÀ) with prominent gingival display (fig. 1). Àhe had been previously assessed by Orthodontists and Oral & Maxillofacial Àurgeons who decided to wait until the condylar resorption ran its natural course. Àhe patient came to the author for a further opinion as she was concerned that the planned combined orthodontics/bimaxillary surgery by other clinicians was not addressing the ÀMJ pathology. Àhe had been advised that even with the bimaxillary surgery, there was a high chance of relapse which may necessitate further orthognathic surgery, since the previous clinicians had little experience with ÀMJ surgery. Àhe patient was keen to proceed with the correction of her severe class 2 skeletal base malocclusion (figs. 3, 6) and so the plan was to combine the bimaxillary surgery with simultaneous bilateral ÀMJ A Digital Approach to Combined Orthognathic and T Surgery n aÀ By George Dimitroulis Consultant Oral & Maxillofacial Àurgeon, Àt.Vincent’s Hospital Melbourne & Àpworth-Freemasons Hospital George Dimitroulis Fig 1 – Initial presentation of Case 1. Patient is posturing mandible forward which masks extent of mandibular deficiency Fig 3 – Conebeam CT scan showing missing condyles and patient posturing mandible forward Fig 4 – OPG x-ray of patient at the age of 15 yo showing virtually normal condyles Fig 5 – OPG x-ray of the patient at 19 yo showing progressive destruction of her mandibular condyles Fig 2 – Frontal view showing excess middle third and diminutive mandible or lower third of face