mise à jour du
13 mai 2006
2005; 28(112):27-29
Bilateral dislocation of the mandible
2 cases in a nuclear family
Etisiobi Ndiokwelu
University Nigeria, Enugu
Bâillements et stomatologie


Dislocation whether unilateral or bilateral can be distressing. It imposes both psychological and physiological trauma, leading some victims, out of ignorance, to look for treatment for what is purely physical, in the metaphysical realms. This delays the right treatment and can make what initially was a simple case a complex one.
Proper understanding of the mechanism and treatment of dislocation will go a long way to save time, money and improper treatment. Some have gone from one clinic to another and even to quacks where injections are given with unsterilized needles. In this era of HIV/AIDS explosion, the risk of contracting infection is high, hence the need for proper understanding and prompt management of this condition.
CASE 1 : A 20-year-old secondary school student, obviously distressed, with worried family members reported on the 26th April 1999. He had yawned and the mouth did not close. It remained open for about a month during which they had gone to some clinics and later to native doctors. Some used hammer, others used steam bath whereas some did incantations. The parents were later advised to go to the orthopedic hospital clinic. He eventually came to the University of Nigeria Teaching Hospital (UNTH) and was referred to the dental clinic.
CASE 2 : This case is the senior brother of the first case in a nuclear family. He was aged 23 years. Reported on the sixth day of the dislocation. History showed that it was triggered off by vomiting as a result of sickness (self-diagnosed malaria). He was a student of a polytechnic and reported at the medical center where the doctor expressed his inability to help. He took no drugs but contacted the junior brother who had a similar episode, who then brought him down to Enugu immediately.
He has not been able to close his mouth and he could not chew food and depended on foods that could be swallowed without chewing. This was the first time dislocation ever occurred on him.
Teeth present 8-1 1-8
8-1 l-8
Oral hygiene was fair. Because of the dislocation the lower third molar was articulating with upper second molar. There was obvious symmetry indicating bilateral involvement of the two joints.
X-rays - TMJ views, PA. oblique lateral right and left were ordered. There was a history that their mother had a dislocation before she got married. This information was elicited out of curiosity when the second case occurred in the same nuclear family in a space of 17 months.
Treatment consisted of seating the patient at a low level. The thumb of each hand was wrapped (protected) to avoid injury from the teeth when the mandible snaps into place. The padded thumbs were then placed bilaterally on the molars as far posteriorly as possible. The fingers of the hands rested under the body of the mandible near the symphisis. While this direction of force was being applied, a backward force was slowly utilized. The thumb served as a fulcrum thus lowering the condyle below the level of the crest of the eminence. The backward force then placed the condyle n the gleniod fossa
Immediately after the reduction was made, the area around the joint was massaged and the patient instructed to avoid opening the mouth to any great extent. A bandage limiting the motion of the jaw, yet allowed the patient some four weeks freedom of mastication, speech and oral hygiene. This allowed the healing and contraction of the ligaments.
Dislocation : A dislocation may be defined as variation from normal of the position of the articulating surfaces of ajoint. There is an attachment from every side that may be compared to that of wires holding a tent pole in defiance of force from any direction. However on some occasions if the force is great there may be resultant dislocation. In order for a dislocation to occur, certain attachments must release some tension, and consequently there will be a strained ligament or fractured bone or a combination of the two. In any form dislocations are very painful and render the jaw useless. There are six types of dislocations each named for its direction of dislocation. They are superior, posterior, medical, lateral, inferior and anterior. The first three mentioned are always associated with fractured bones, whereas this is not necessarily true in connection with the latter three named.
The anterior dislocation is by far the most common, the other five being comparatively infrequent.
Anatomy: The condylar process stands up from the posterior part of the ramus and forms the head and neck of the mandible. The neck lies immediately anterior to the lobule of the auricle, the head is in front of the tragus. Note that the mouth cannot close while the finger lies in this fossa.
Diagnosis of dislocation : There are two important classes to making diagnosis: Inability to close the mouth. Movement of them is very limited and the mouth is held open, extremely wide in complete bilateral case. The unilateral case presents a picture of asymmetry. The great pain expressed by the patient. Pressing-the tips of index fingers over the joint may feel a deep depression due to the absence of the condyles.
Anterior dislocation : This type of dislocation is seldom associated with a fracture and may result from minor accidents. Mastication, laughing, yawning, sneezing may induce dislocation. As the mouth opens, the anterior, superior surface of the condyle rocks forward contacting the inferior distal surface of the articular eminence. If, at this time, some force such as opening the mouth too wide, forces the condyle anterior to the crest of the eminence, it becomes locked there with the coronoid process locked beneath the zygomatic process of the molar bone. The extreme pain tends to cause greater muscle contraction; therefore, in many cases a reduction is no easy task. Most of the pain is derived from strained ligaments.
There are two important factors which influence the case of dislocation: I. The number of previous dislocation encountered by the patient 2. The length of time that each dislocation was allowed to remain as such. In this connection it is pertinent to recall a case that resisted manual reduction even under general anesthesia because the patient erroneously believed it was the handiwork of evil men and did not seek for orthodox treatment for more than a year. In this type, effusion into the joint, following the injury becomes organized forming fibrous adhesions. Treatment required open operation to devest adhesions must be carried out.
MARKOWITZ and GERRY made a distinction between complete and incomplete dislocation or luxation by interpretation of x-rays. If the condylar head is found to be in front of the articular eminence but not in a superior position, it is considered incomplete dislocation or a subluxation; if the condytar head is found to be in a position anterior and superior to the crest of the articular eminence, it is considered true dislocation or luxation.
Treatment of chronic dislocation
Some authors advise against open operation on the joint in chronic cases for fear of possible ankylosis.
They advocate injection of 95 percent alcohol and claimed success with several stubborn cases. The injection is made immediately against the capsular ligament but not piercing it. The insertion of temporalis muscle is also injected.
A third injection is made at the inserting third of the masseter muscle. These injections are made bilaterally. HELMAN et al. gave option of eminectomy (reducing the angle of the plane of the articular eminence) in chronic dislocation. When the condyle is dislocated the head of the condyle is locked just anterior to the articular eminence. This surgical procedure allows a normally smooth forward and backward movement of the condyle as the patient opens and closes. After reviewing eight cases so treated they recommended the surgical procedure where there is chronic dislocation of TMJ and radiographic evidence of a deep glenoid fossa and high pronounced eminence.
Bilateral dislocation is not a frequent occurrence. To have occurred in two siblings within a period of 17 months raises the question whether there is a predilection to this occurrence within this nuclear family. Since there was history of this occurring to the mother long before marriage, there is good reason to suspect a greater susceptibility in the family for this condition
Two cases of bilateral dislocation occurred in two brothers, aged 20 and 23 within a period of seventeen months. The junior one was the first victim in the month of April 1999 and the senior brother later in November 2000. The first was triggered by yawning whereas the second by vomiting. Different types of dislocation, diagnosis and management of dislocation is presented. The occurrence in two siblings raises the question of familial predisposition to dislocation.
Nous rapportons deux cas de dislocation bilatérale chez deux frères ages de 20 et 23 ans durant une période de 17 mois. Le cadet était le premier victime de dislocation en avril 1999. lainé en fut victime, plus tard, en novembre, 2000. Le premier cas était consécutif à un bâillement, alors que le deuxième cas était suite à un vomissement. Différents types de dislocation sont présentés, ainsi que le diagnostic et le traitement. La présence de dislocation bilatérale chez deux enfants dun même couple soulève la question d'une prédisposition la dislocation bilatérale chez les membres de cette famille.

MARKOWITZ HA, GERRY RG. Temporomandibular joint disease. Oral Surg Oral Med Oral Pathol. 1950;3(1):75-117.