TMJ Coronoid Hyperplasia with Anterior Open Bite Relapse After Maxillary Surgery – A Case Study

by Clayton A. Chan, D.D.S., M.I.C.C.M.O.

The restricted mandibular opening (TMJ) problem can be often mis-iagnosed and mis-treated when the underlying problem is really an undetected “elongated coronoid hyperplasia” resulting from abnormal hyperactive temporalis anterior muscle activity due to a posterior abnormal jaw closure patterns. Patients can exhibit decreased mandibular opening and may have a limited lateral excursions due to a hinging or locking into the zygomatic process or even fuse with it.  Patients are usually painless unless an attmpt is made to increase the restricted opening. Limited opening could be due to connective tissue disease (e.g., scleroderma, lupus) following (capsular fibrosis – fibrous or osseous) and skeletal abnormalities (e.g coronoid hyperplasia). In unilateral situations, a decreased lateral excursion will occur toward the contra-lateral side.

Anterior open bites can also be mis-diagnosed and mis-treated when the underlying neuromuscular causes are not acknowledged and not recognized. Abnormal tongue habits as well as abnormal swallowing patterns will occur when there is an imbalance of masticatory muscles activity present and lack of proper occlusion to support proper intra oral tongue posture.

Case Study:
A 26 year old caucasian male presented with severely restricted jaw opening.

Chief Complaint:

  • Pain in jaw joints – bilateral
  • Pain in neck – bilateral
  • Pain in shoulder – bilateral
  • Headaches – bilateral
  • Fullnes
    s in ear – left
  • Inability to open his mouth – 21.8 mm incisal edge to incisal edge
  • Difficulty to chew, swallow, load snoring
  • Constantly tired
  • Mouth breathing at night
  • Dry mouth
  • Severe canker sores – ulcerations, (Sores develop 2-3 times monthly contributing compromised eating, sleeping and day time awake work habits).
  • Flexirl seems to help
  • Inability to eat

Previously he has seen various doctors, physical therapists and medical doctors.  Some MD’s  thought his problem was attributed to possible connective tissue disorder.  See X-ray of lungs.

No other significant medical/dental clinical finding were observed.

Patient presented numerous radiographs of his before surgery and after surgery.

During consultation patient was asked to protrude the mandible forward – no movement- abrupt hard end restriction was noted!

Clinical Findings on Brief Consultation:

  • Patient has severely restricted opening
  • No protrusive movement
  • Severely limited left and right excursive movement.
  • No end give on finger pressure.
  • ROM severely restricted – 21.8 mm max open.
  • At age 17 he could move mandible more freely.
  • 10 years later no mandibular movement.
  • Lower facial features show atrophic appearance.
  • Patient very alert, active.
  • Considering consulting to cope with situation.
  • Loosing weight and can’t eat effectively.
  • Discussed etiology, treatment options.

Patient had previous surgery of maxillary to correct anterior open bite in year 2000.  It relapsed in 2001.

  • Patient spent $45,000
  • Insurance did not pay

8-31-00, Age 23 (Anterior Open Bite – Before Surgery)

10-30-00 (After Maxillary Surgery to Close Anterior Open Bite)

11-7-01 (Tomograms of Left and Right TMJ)

11-7-01 (Lateral Cephalogram After Anterior Open Bite Closure Surgery)

11-10-04 (Relapse Anterior Open Bite After Surgery) – Note: Un-diagnosed elongated coronoid process of both left and right sides indicative of coronoid hyperplasia.

Patient was immediately referred to neuromuscular Oral Surgeon for evaluation and treatment for bilateral coronoidectomy.

Scientific Studies Have Shown:

The results of the Levandoski analysis (Evaluation of the role of coronoid hyperplasia in recurrent  unilateral temporomandibular joint (TMJ) ankylosis using the Levendoski analysis) was useful in the correct categorization of 16 patients. Selected surgical treat­ment approach were also successful. Studies show there was no recurrence in any of the cases. Although the initial limita­tion of mouth opening shows some tendency to diminish, yet the relapse (recurrence) was even less when an ipsilateral coronoidectomy was performed.  The decision to perform an ipsilateral co­ronoidectomy based on our criteria also proved successful.  There was a significant improvement in maximal interincisal distances, and protrusive excursions for group II patients.  Coronoidectomy did not much affect lateral excursions.  Elongated coronoid processes were more frequently associated with males, older aged subjects, and cases of longer duration, an additional observation of this study.

Surgical removal of the elongated coronoid processes, along with good postoperative range-of-motion exercises, will restore full mandibular movement.
It is the conclusion of these studies that cases of  TMJ ankylosis should undergo coronoidectomy in addition to arthroplasty. Special attention should be paid to adult males with a prolonged duration of unilateral/bilateral TMJ ankylosis. Furthermore, while CT is recommended for the correct diagnosis and documentation of the ankylosed joint and its dimen­sions, yet the simply obtainable panoramic radiograph should always be used for the presented anal­ysis and diagnosis of an elongated coronoid process.

About

The Originator of the Chan Optimized Bite™. He is considered by many to be the authority on Neuromuscular Occlusion and its application to Clinical Dentistry. Dr. Chan is a general dentist, clinician, teacher, educator and leader .

Director, Occlusion Connections™ Center for Gneuromuscular Dentistry & Orthopedic Occlusal Advancement
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