Anterior disc displacement of the temporomandibular joint (TMJ), also known as internal derangement, is common in both children and adults [1, 2]. It can result in clicking, joint pain, a limited mouth opening, masticatory difficulties, and degenerative changes of the condyle. Moreover, TMJ disorders or pathology and dentofacial deformities commonly coexist, and now many oral surgeons and orthodontists have associated anterior disc displacement with facial growth restrictions and development of jaw deformities [3–11]. Surgically induced disc displacement in rabbits has shown that unilateral anterior disc displacement led to mandibular asymmetry, while bilateral anterior disc displacement led to mandibular retrognathia [12, 13]. Our clinical observations using magnetic resonance imaging (MRI) have also shown a high prevalence of mandibular asymmetry in juveniles with unilateral anterior disc displacement, whereas the condylar growth on the affected side could be suppressed [14, 15].

During the last two decades, under the leadership of Prof. Yang, the surgeons of our department have been developing a combined Joint-Jaw-Occlusion (JJO) protocol, including examinations, diagnosis, and treatment procedures. Treatments targeting the TMJs include arthroscopic disc reposition and suturing [16, 17], disc reposition and anchorage with open surgery [18, 19], mandibular reposition therapy with splint, and joint reconstruction with a chondrocostal graft or artificial joint. Needless to say, manipulations of the joint always induce changes in occlusion and facial profile, and vice versa. To consolidate the result of TMJ surgical interventions, we applied occlusal treatment. Orthodontic methodologies are employed to solve occlusal problems prior or subsequent to TMJ interventions. Orthognathic and orthopedic treatments are also applied to moderate to severe jaw deformities in adults and adolescents, respectively.

1. Early stage disc displacement with reduction treated with anterior repositioning appliance

In 1976, L.A. Weinberg published an article discussing the use of a splint for the forward reposition of the mandible in order to resolve TMJ symptoms followed by permanent prosthesis to hold the mandible in this position [20]. With the development of arthrography in 1970s, the recognition of anterior disc displacement ignited the use of anterior repositioning splint (ARS) to “recapture” the disc [21, 22]. Subsequent to anterior repositioning splint-therapy, orthodontic treatments would be needed to maintain the splint position.

Cases of early stage anterior disc displacement with reduction with deep overjet, deep overbite and Class II relationship could be treated with anterior repositioning therapy which corrects the disc position relating to the condyle while achieving a Class I intermaxillary relationship. Therefore the patient with such indications would benefit in both TMJ symptoms and profile, and occlusion as well. In our department, functional appliances were also used to advance the mandible, including the Twin-Block, Herbst, Activator, and Forsus, etc., which were called, in combination with anterior repositioning splint, anterior repositioning appliance. Since 2009, our team has treated 163 cases of anterior disc displacement with reduction, involving 231 joints.

1.1. Anterior repositioning appliance without orthodontics

Sometimes, a stable Class I occlusion could be achieved at the end of the therapy and there would be no need for further orthodontics. For example, this case of right side anterior disc displacement with reduction was a 21-year-old patient, with Class II molar relationship on both sides.

  • image01 Fig. 1
    • Fig. 1. MRI before treatment showed anterior disc displacement with reduction on the right side
  • image02 Fig. 2
    • Fig. 2. Lateral facial profile and lateral cephalometry
  • image03 Fig. 3
    • Fig. 3. Occlusion

    For further diagnosis, a wax bite registration of the therapeutic mandibular position was made, and the patient was scheduled a MRI examination again wearing this bite registration to confirm a better disc-condyle relationship

  • image04 Fig. 4
    • Fig. 4. Diagnostic MRI wearing wax bite registration: it was confirmed that when the mandible was repositioned forward, a normal disc-condyle relationship was restored with a pronounced increase of the posterior joint space on both sides

    An anterior repositioning splint was then fabricated according to the bite registration, and the patient was told to wear it 24 hours a day.

  • image05 Fig. 5
    • Fig. 5. Wearing the anterior repositioning splint

    The anterior repositioning splint would be gradually ground to allow the lower molars and premolars to erupt. When the lower molars erupt to occlusal contact with the upper teeth, the anterior repositioning splint would be removed.

  • image06 Fig. 6
    • Fig. 6. Grinding of the anterior repositioning splint
  • image07 Fig. 7
    • Fig. 7. After removing of the anterior repositioning splint: molars and incisors contacted with the openbite on the premolar region and decreased the overbite and overjet
  • image08 Fig. 8
    • Fig. 8. MRI at the end of the therapy: normal disc-condyle relationship, slightly increased posterior space, and modification of both condyles
  • image09 Fig. 9
    • Fig. 9. Lateral facial profile and lateral cephalometry showed an improved lateral profile and an increased lower facial height

    After one year of spontaneous adaptation, the mandible was finally seated and due to a Class I relationship and good interdigitation, the final result was quite stable.

  • image10 Fig. 10
    • Fig. 10. Final occlusion after 1 year follow-up
  • image11 Fig. 11
    • Fig. 11. MRI 1 year follow-up: bilateral normal disc-condyle relationship, even anterior and posterior space and the signal of the original cortical bone on the condyle surface is fading
  • image12 Fig. 12
    • Fig. 12. Summary of the joint and occlusal changes

    To sum up, the indications should be chosen with great caution to achieve stable results. Otherwise, the relapse rate of such treatment would be very high. Establishing a Class I relationship with good interdigitation could be helpful for the stability of regained disc position.

    1.2. Anterior repositioning appliance followed by orthodontics

    When the occlusion could not be seated through spontaneous adaptation, however, a second phase of orthodontic treatment would be necessary to solve the subsequent problems. This case was a 22-year-old female patient who complained of clicking on both TMJs with Class II molar relationship and deep overbite/overjet, but at the same time, presented with an inclined left upper lateral incisor, which turned out to be an early contact when the mandible was advanced.

  • image13 Fig. 13
    • Fig. 13. MRI: bilateral anterior disc displacement with reduction
  • image14 Fig. 14
    • Fig. 14. Lateral facial profile and lateral cephalometry
  • image15 Fig. 15
    • Fig. 15. Original occlusion: Class II, deep overbite/overjet, upright upper incisors and inclined left upper incisor

    The upper anteriors were aligned before the application of the mandibular advancement instrument.

  • image16 Fig. 16
    • Fig. 16. Upper anteriors were aligned first to eliminate occlusal interference, and Herbst appliance was then induced to move the mandible forward to a therapeutic position

    One year passed before the appliance was removed to stable the disc position and allowed the condyle to remodel.

  • image17 Fig. 17
    • Fig. 17. After mandibular advancement: typical subsequential occlusal problems occured: the posterior openbite, with Class III molar relationship, multiple spaces in the upper arch, crowding in the lower arch, and very deep curve of Spee
  • image18 Fig. 18
    • Fig. 18. MRI at the end of Phase I showed positive results: normal disc-condyle relationship, slightly increased posterior space, and modification of both condyles

    Brackets were then applied and Phase II started to seat the occlusion and stabilize the mandibular position.

  • image19 Fig. 19
    • Fig. 19. Application of brackets

    Finally, Class I molar relationship and good interdigitation were achieved. The patient’s profile and occlusion were also improved through the protocol.

  • image20 Fig. 20
    • Fig. 20. MRI after the completed procedure
  • image21 Fig. 21
    • Fig. 21. The final lateral facial profile and lateral cephalometry
  • image22 Fig. 22
    • Fig. 22. Removal of the brackets

    After the Herbst’s removal, 4 years had passed when the patient came for the follow-up. The result was still stable.

  • image23 Fig. 23
    • Fig. 23. Occlusion at the follow-up
  • image24 Fig. 24
    • Fig. 24. MRI examination at 4 years of the follow-up (after anterior repositioning therapy)

    1.3. Anterior repositioning appliance as prosthesis or followed by prosthodontics

    Elderly patients with the same condition, but with a lower remodeling potential of joints and occlusion, need to be treated with prosthodontics, or wearing anterior repositioning splint for a long term to maintain the mandibular position.

  • image25 Fig. 25
    • Fig. 25. An elderly female with bilateral anterior disc displacement with reduction
  • image26 Fig. 26
    • Fig. 26. MRI: disc displacement on both sides
  • image27 Fig. 27
    • Fig. 27. Class II relationship and deep overjet

    A wax bite registration for MRI to confirm the disc repositioning was even more important because we planned for a less overcorrection when the therapeutic mandibular position was decided, due to the intention to ask the patient to wear her anterior repositioning splint for a long period.

  • image28 Fig. 28
    • Fig. 28. Diagnostic MRI wearing wax bite registration

    A smaller, more comfortable splint was made to fit into the posterior openbite.

  • image29 Fig. 29
    • Fig. 29. Anterior repositioning splint on lower arch
  • image30 Fig. 30
    • Fig. 30. Follow-up MRI with/without anterior repositioning splint

    The disc position is normal without wearing splint. However, no signs of remodeling were noticed. The joint space changed slightly when the splint was taken off. Therefore, we consider this kind of mandibular position to be highly unstable. The patient either chooses to wear the anterior repositioning splint for long term, or has to switch to fixed prosthesis to hold the mandible.

    For patients with missing teeth, anterior repositioning splint could also be adapted with partial denture.

  • image31 Fig. 31
    • Fig. 31. Anterior repositioning splint with removable partial denture

    2. Disc displacement treated surgically (open or endoscopic surgery) that combined the anterior repositioning appliance with/without orthodontics

    To eliminate any mechanical interference due to TMJ internal derangements, disc reposition is a common procedure for patients at late stage of anterior disc displacement with reduction and anterior disc displacement without reduction. Various modified disc repositioning techniques have been described, including arthroscopic suturing techniques, but with unsatisfactory success rate and long-term stability [23–25].

    In our department, therapeutic arthroscopy has been carried out for more than 30 years. A new arthroscopic disc repositioning and suturing technique was developed in 2001 [16]. An MRI evaluation of the short-term results has demonstrated a high success rate of 95.42% [17]. Bone anchorages were also used to fix the disc in open reduction surgeries since 2003 [18, 19].

    Subsequent to the surgery, a slight posterior openbite could always be noticed, similar to the anterior repositioning therapy. We commonly applied elastics on the posterior teeth to close this openbite if it failed to adapt spontaneously at 3 months after the surgery. However, it was not long before our team realized that the cause of this phenomenon was the volume (especially thickness) of the disc which increased the posterior space and pushed the mandible downwards and forwards. Since the occlusion has already gradually adapted to the dislocated mandible (with a shorter vertical height and horizontal depth on the ipsilateral side) through a relatively long history of anterior disc displacement, it was only reasonable to witness an occlusal discrepancy after a sudden change of condyle position induce by the surgery. So it was better to keep this posterior openbite in order to relieve the pressure inside the capsule, let the attachments around the disc to heal and let the teeth to adapt. Moreover, studies have proved that with advancing the mandible forward, the disc on the other side actually moved backwards towards the fossa. This means that anterior repositioning appliance could also be applied after surgery in the situation of Class II malocclusion. It was a win-win situation that mandibular advancement after surgery promoted the stability of disc reposition, facial profile, and occlusion at the same time.

    Since 2009, we have applied anterior repositioning appliance in 390 cases after arthroscopic disc repositioning and suturing, and 227 cases after disc reduction and anchorage performed by Prof. Yang.

    2.1. Application of the Herbst appliance after arthroscopic disc repositioning

    The following case was a 15 years old male, who had anterior disc displacement without reduction on the left side and anterior disc displacement with reduction on the right side.

  • image32 Fig. 32
    • Fig. 32. Diagnositic MRI wearing wax bite registration
  • image33 Fig. 33
    • Fig. 33. Deep overbite and deep overjet with Class II relationship
  • image34 Fig. 34
    • Fig. 34. Initial occlusion

    The arthroscopic disc reposition was planned for anterior disc displacement without reduction, while the anterior disc displacement with reduction on the right side could be treated by anterior repositioning appliance after surgery.

  • image35 Fig. 35
    • Fig. 35. MRI: 2 weeks after left joint arthroscopic surgery

    The Herbst was applied two week after the surgery. The disc on the right side was than captured, with posterior joint space increased on both sides.

  • image36 Fig. 36
    • Fig. 36. MRI after application of the Herbst appliance: disc was captured and normal disc-condyle relationship was restored. Meanwhile on the left side the disc was moving backwards relative to the condyle, thus consolidating the surgical reposition of the disc
  • image37 Fig. 37
    • Fig. 37. Occlusal change

    The use of the Herbst appliance lasted for 10 months before the condyle remodeling took place and bilateral posterior joint spaces were almost filled.

  • image38 Fig. 38
    • Fig. 38. MRI after application of the Herbst: new bone formation could be seen on both sides
  • image39 Fig. 39
    • Fig. 39. After the Herbst treatment

    Then the second phase of treatment began.

  • image40 Fig. 40
    • Fig. 40. Application of brackets

    The whole procedure took 26 months.

  • image41 Fig. 41
    • Fig. 41. MRI: final bilateral normal disc position
  • image42 Fig. 42
    • Fig. 42. Improved overbite and overjet with Class I relationship
  • image43 Fig. 43
    • Fig. 43. Stable occlusion

    The application of anterior repositioning appliance after TMJ disc reposition and suturing procedure surgery brings benefits in several ways: stabilization of the surgical outcome by creating of a condyle-forward, disc-backward movement; an early stage of anterior disc displacement with reduction could be corrected simultaneously with no extra cost to either the patient, or the dentist; and last but not least, the increased posterior space very soon after the surgical reposition or “recapture” of the disc seemed to be able to stimulate the condylar remodeling after puberty, even in young adults, as we presented in prior sections. Its mechanism and long term results should still be investigated further.

    2.2. Application of the Herbst after open anchorage

    The use of anterior repositioning splint or other anterior repositioning appliances after open anchorage shares the same mechanism.

  • image44 Fig. 44
    • Fig. 44. MRI: bilateral anterior disc displacement without reduction
  • image45 Fig. 45
    • Fig. 45. Deep overbite and overjet with Class II relationship
  • image46 Fig. 46
    • Fig. 46. Initial occlusion
  • image47 Fig. 47
    • Fig. 47. Anterior repositioning splint after surgery
  • image48 Fig. 48
    • Fig. 48. Phase II, orthodontic treatment
  • image49 Fig. 49
    • Fig. 49. MRI: the outcome
  • image50 Fig. 50
    • Fig. 50. The outcome
  • image51 Fig. 51
    • Fig. 51. Final occlusion

    3. Orthodontics needed first: Class II division 2

    Occlusal interference should be taken care of before surgery. The following case shows how certain malocclusion may jeopardize the joint health.

    This 22 year-old female was referred to our clinic for pre-orthodontic examination in Nov. 2014 due to a Class II division 2 malocclusion.

  • image52 Fig. 52
    • Fig. 52. Pre-ortho MRI: normal disc-condyle relationship on the right side, slight anterior displacement on the left side without clinical symptoms

    As MRI showed negative diagnosis, her dentist started his treatment by bonding the lower arch first and planned to extract upper first premolars since there has been a congenital missing lower incisor and crowding in the upper arch.

  • image53 Fig. 53
    • Fig. 53. After alignment of the lower arch

    However, at 2.5 months into orthodontic treatment, she complained of pain in the right TMJ and limited mouth opening. Another MRI was then scheduled in Jan. 2015.

  • image54 Fig. 54
    • Fig. 54. Anterior disc displacement without reduction was detected on the right; with the left side almost the same as before

    It has been acknowledged that Class II division 2 malocclusion is a highly significant relative risk factor for the onset of anterior disc displacement. Yet, it is extremely rare to capture such a procedure. Considering the mechanism behind this, it could only be deduced that the alignment of the lower dentition broadened the lower arch and increased the arch depth. Combined with the restriction of the upper arch (where most teeth were inclined), the mandible was passively pushed backward, as was the right condyle where the force concentrated, and the disc was squeezed forward.

    In our opinion, in such cases it is vital to broaden the upper arch first. Thus, we removed the arch wire on the lower arch, and started to upright upper teeth so that the mandible could move forwards and downwards smoothly after the disc reposition.

  • image55 Fig. 55
    • Fig. 55. Upper teeth uprighted
  • image56 Fig. 56
    • Fig. 56. Anterior movement without interference
  • image57 Fig. 57
    • Fig. 57. Application of anterior repositioning splint after surgery
  • image58 Fig. 58
    • Fig. 58. Further advancing of the mandible forwards at 3 months after surgery
  • image59 Fig. 59
    • Fig. 59. After 1 year of anterior repositioning splint treatment: upper and lower teeth are aligned. The occlusion was stable with good interdigitation
  • image60 Fig. 60
    • Fig. 60. After the surgery with mandibular reposition: good disc position on the right side, and better disc position on the left side (without surgery)
  • image61 Fig. 61
    • Fig. 61. Normal disc-condyle relationship on both sides without wearing the anterior repositioning splint and a slight remodeling on the posterior slope of the left condyle could be seen
  • image62 Fig. 62
    • Fig. 62. Maintained esthetics of the lower part of the face, proved position of the lower lip

    The TMJ and occlusion results were both satisfactory and the appliance could be removed (will be done on the next review).

    This case proved that Class II division 2 malocclusion does increase the intracapsular stress and may lead to disc displacement. When dealing with this kind of patients, it is important to set the mandible “free” by broadening of the upper arch instead of restricting the lower dentition with inclined upper teeth.

    We advanced the mandible forwards step by step for young adults whose potential of condyle remodeling were limited. Also, for patients with shortened discs, too much advancing the mandible forwards at once might separate the disc and the condyle, which is considered a hazard for the TMJ adaptation. Other occlusal interference, such as individual tooth malposition, arches width discrepancy, and scissors bite with a functional early contact should also be resolved as quickly as possible before surgery.

    4. Severe oral-maxillo-facial deformities: TMJ and orthognathic surgery

    Temporomandibular joint disorders and dentofacial deformities commonly coexist. Many of our patients were referred to by orthodontists and orthognathic surgeons (34.72%). Some moderate to severe deformities could not be corrected through conservative treatment. However, an unbalanced oral-facial force distribution might jeopardize the disc-condyle relationship, especially after surgery. It is better to restore normal facial morphology simultaneously with the joint surgery.

    Since 2009, we have performed 15 simultaneous TMJ and orthognathic surgeries and 11 second-stage orthognathic surgeries following TMJ surgeries. The most common deformities that coexist with anterior disc displacement are facial asymmetry and mandibular retrognathia.

    4.1. Facial asymmetry

    A 19 years old female was referred to us by orthognathic surgeons due to joint form discrepancy between the ipsilateral and contralateral TMJs and severe mandibular deviation.

  • image63 Fig. 63
    • Fig. 63. Severe mandibular deviation
  • image64 Fig. 64
    • Fig. 64. Disc displacement on the left and the condyle were much smaller than at the right side
  • image65 Fig. 65
    • Fig. 65. Unbalanced occlusal relationship was also moticed
  • image66 Fig. 66
    • Fig. 66. The dentitions were aligned and decompensated
  • image67 Fig. 67
    • Fig. 67. Simulation of the orthognathic surgery

    Arthroscopic disc reposition and suturing was performed together with bimaxillary orthognathics.

  • image68 Fig. 68
    • Fig. 68. Occlusion was ballanced
  • image69 Fig. 69
    • Fig. 69. Final occlusion
  • image70 Fig. 70
    • Fig. 70. Final profile
  • image71 Fig. 71
    • Fig. 71. MRI at half a year after the surgery: the disc is in a very stable position

    4.2. Retrognathia

    Case 1. Simultaneous arthroscopic disc reposition and orthognathics

    A 24 years old female, whose chief complaint was losing anterior occlusion, was diagnosed bilateral anterior disc displacement without reduction, condylar resorption and mandibular retrognathia. She also presented with a typical “horizontal anterior openbite” which indicated a history of condylar resorption.

  • image72 Fig. 72
    • Fig. 72. Mandibular discrepancy with a large overjet, and 0 mm overbite
  • image73 Fig. 73
    • Fig. 73. This kind of occlusion rings a bell of condylar resorption
  • image74 Fig. 74
    • Fig. 74. MRI comfirmed our deduction
  • image75 Fig. 75
    • Fig. 75. Disc reposition was performed simultaneously to the mandibular bilateral sagittal split osteotomy of the ramus
  • image76 Fig. 76
    • Fig. 76. Lateral profile before, at 3 months after and 1 year after surgery
  • image77 Fig. 77
    • Fig. 77. Lateral ceph
  • image78 Fig. 78
    • Fig. 78. Improved intermaxillary relationship
  • image79 Fig. 79
    • Fig. 79. A good disc position and remodeling of the condyle

    Case 2. Chondrocostal Graft and mandibular advancement

    This 21 years old female also complained of having lost her anterior occlusion, whereby her chin was gradually moving backwards. She also started to snore for a short period. She had difficulties with closing her lips and breathed with her mouth during sleep.

    None of the complaints, however, seemed to be related to TMJ internal derangements or any kind of TMJ disorders.

  • image80 Fig. 80
    • Fig. 80. Severe mandibular retrognathia
  • image81 Fig. 81
    • Fig. 81. Typical occlusion of condylar resorption: Class II molar relationship and anterior openbite
  • image82 Fig. 82
    • Fig. 82. MRI: bilateral disc displacement without reduction, severe disc deformities on both sides, and a very small, abnormally shaped condyle. Bone inflamation was seen all over the condylar head

    MRI helped to reveal the true nature of her condition: anterior disc displacement without reduction, joint arthritis, and severe condylar resorption, which was accountable for ongoing mandibular retrusion.

    For unsalvageable discs and condyles, chondrocostal graft was planned. The benefit was that bilateral sagittal split osteotomy of the ramus would no longer be needed because we could increase the posterior facial height with a rib graft and advance the mandible forwards.

  • image83 Fig. 83
    • Fig. 83. The large overjet was created before the surgery to provide a space for mandibular advancement
  • image84 Fig. 84
    • Fig. 84. The mandible was repositioned with the support of the chondrocostal graft
  • image85 Fig. 85
    • Fig. 85. Improved facial profile
  • image86 Fig. 86
    • Fig. 86. The final occlusion
  • image87 Fig. 87
    • Fig. 87. The profile at 3 years of the follow-up after the procedure was completed

    Unilateral or bilateral TMJ reconstruction with chondrocostal graft or artificial joints provides us with an alternative for lower jaw orthognathic operations. Many patients with TMJ internal derangements needing joint reconstruction present with severe jaw deformities. With careful diagnosis and treatment plan design, an osteotomy could be avoided, as well as its complications, such as numbness of the lower lip.

    By combining artificial TMJ prosthesis with maxillary orthognathic operation, extremely severe facial morphologic abnormalities can be resolved with promising long term stability.


© Ян Ч., Хэ Д., Чэнь М., Чжан Ш., Цю Я., Чжан С., Ма Ч., Се Ц., Шэнь П., Ху И., 2017

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