Coronoid process hyperplasia: an unusual cause of mandibular hypomobility

Abstract

A large number of disorders affecting the masticatory system can cause restriction of mouth opening. The most common conditions related to this problem are those involving the temporomandibular joint (TMJ) and the masticatory muscles, when facial pain also is an usual finding. Congenital or developmental mandibular disorders are also possible causes for mouth opening limitation, although in a very small prevalence. Coronoid process hyperplasia (CPH) is an example of these cases, characterized by an excessive coronoid process growing, where mandibular movements become limited by the impaction of this structure on the posterior portion of the zygomatic bone. This condition is rare, painless, usually bilateral and progressive, affecting mainly men. Diagnosis of CPH is made based on clinical signs of mouth opening limitation together with imaging exams, especially panoramic radiography and computerized tomography (CT). Treatment is exclusively surgical. This paper presents a case of a male patient with bilateral coronoid process hyperplasia, initially diagnosed with bilateral disk displacement without reduction, and successfully treated with intraoral coronoidectomy. It is emphasized the importance of differential diagnosis for a correct diagnosis and, consequently, effective management strategy.

Clinical and radiological features of Jacob’s disease. A case report involving an osteochondroma of the coronoid process

“…The mandibular hypomobility can lead to secondary problems such as airway problems, malnutrition and growth retardation, negative impact on speech development, limited access to oral hygiene and dental care, and muscle atrophy [6].…”

Mouth opening limitation caused by coronoid hyperplasia: a report of four cases

“…Some authors have reported that using a Water's view radiograph in the mouth open position2 or comparing the distance between the horizontal line of the coronoid process and the horizontal line of the condyle head using Levandoski panoramic radiograph analysis12,13 could be useful diagnostic methods when plain X-rays are used. Kubota et al13 measured the ratio between the length of the coronoid process and the length of the condylar process of patients with coronoid process hyperplasia and a control group using Levandoski panoramic radiograph analysis and reported that a ratio greater than 1.1 indicates that further evaluation is necessary because coronoid process hyperplasia is likely.…”

“…Creating plastic models of the skull, such as the rapid prototyping model, has also been reported as a suitable diagnostic method but is of limited use given the costs involved14. Recently, cone-beam CT has been preferred over conventional CT for diagnosis due to the low dose of radiation used and the relatively low cost12.…”

Hiperplasia unilateral do processo coronóide: relato de caso clínico

“…As teorias que fundamentam a eti ologia da hiperplasia do processo coronóide da mandíbula incluem alterações endócrinas, ação de fatores hereditários ou a hiperati vidade do músculo temporal 9,12,13 . O relato de trauma na região e a relação com um osteoma ou osteocondroma também foi considerada 1,3,13,14,15 . Os sintomas apresentados pelos pacientes podem ser limitação dos movimentos mandibulares, sensibilidade dolorosa na região e desvio no movimento de abertura mandibular para o lado afetado 14 .…”