• Imaging Science in Dentistry
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• v.35 no.4
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• pp.231-234
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• 2005

Coronoid impingement can cause limitation of mouth opening. In many cases, it appears to be related to the coronoid hyperplasia. We present a case of mouth opening limitation caused by coronoid impingement on the posterior surface of the zygomatic bone without coronoid hyperplasia. The bony changes in coronoid and zygoma including surface irregularity and discontinuity of the cortex and sclerotic change of inner medullary space were noted on computed tomography (CT) scans in different level of axial planes. Through another CT scans in open mouth position could demonstrate that those bony changes were caused by the contact of both surfaces against each other. In case coronoid impingement is suspected of the many possible causes, the open mouth CT scans will be needed to reveal the direct impingement of coronoid on zygoma even without coronoid hyperplasia.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.11.1-11.6
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• 2017

Background: This case report discusses the unusual presentation of limited mouth opening as a result of bilateral coronoid process hyperplasia. Case presentation: A 14.5-year-old male patient of white Caucasian ethnicity presented with limited mouth opening, mandibular asymmetry, and dental crowding. Investigations confirmed bilateral coronoid process hyperplasia and management involved bilateral intraoral coronoidectomy surgery under general anaesthesia, followed by muscular rehabilitation. Mouth opening was restored to average maximum opening within 4 months of surgery. Conclusion: Limited mouth opening is a common presentation to medical and dental professionals. The rare but feasible diagnosis of coronoid impingement syndrome should not be overlooked.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.4
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• pp.249-254
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• 2012

Bilateral coronoid process hyperplasia is a rare condition characterized by an enlarged mandibular coronoid process. The painless progressive reduction of a mouth opening is caused by coronoid process impingement on the posterior aspect of the zygomatic bone. Hyperplasia of the bilateral coronoid process leads to the restriction of a mandibular opening consequent to the impingement of the enlarged coronoid process on the temporal surface of the zygomatic bone or with the medial surface of the zygomatic arch. The process has been diagnosed as developmental hyperplasia. Otherwise, the development of the coronoid process may be associated with growth hormone. This paper describes a case of trismus caused by coronoid hyperplasia in an idiopathic short-stature patient who received growth hormone therapy by somatropin injections.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 1999.03a
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• pp.38-40
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• 1999

$\cdot$ Arthroscopic management is the effective method with acceptable results for coronoid impingement of stiff elbow contributing to the functional improvement and pain relief. $\cdot$ The functional improvement and pain relief seem to be affected by the severity of a degenerative change of the elbow joint. $\cdot$ Excision of coronoid process is required in a marked limitation of further flexion in addition to deeping of the coronoid fossa and anterior capsular release. $\cdot$ Excision of olecranon tip or posterior capsular release are effective method in severe flexion contracture.

• Journal of Oral Medicine and Pain
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• v.48 no.3
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• pp.112-117
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• 2023

Coronoid process hyperplasia (CPH) of the mandible is a rare condition in which abnormal elongation of the coronoid process leads to chronic mandibular hypomobility. CPH causes impingement or impedance of the coronoid process on the inner surface of the frontal part of the zygomatic bone during mouth opening. The lack of significant symptoms makes the diagnosis difficult. Its etiology remains inconclusive despite several theories being suggested. In this report, three reviewed cases are presented. All three patients visited our clinic with limited mouth opening as the chief complaint. Standard clinical and radiographic examinations were conducted under the initial impression of temporomandibular disorders (TMDs), and restricted jaw movements were confirmed in all cases. The absence of improved signs and symptoms following conservative treatment for TMDs or the indeterminate plain radiographs required the attending clinicians to consider three-dimensional imagery. Computed tomography revealed bilateral coronoid hyperplasia in all cases and impingement on the zygomatic bone in two of the three cases. After concluding that this condition caused the patients' limited mouth opening, the patients were referred to the Department of Oral and Maxillofacial Surgery for possible bilateral coronoidectomy or coronoidotomy. CPH usually presents no symptoms apart from a progressive reduction of mouth opening over time. Diagnosis is often delayed, and patients may undergo unnecessary treatment procedures. Clinicians should be aware of this condition and exercise caution in the differential diagnosis of patients with chronic mandibular hypomobility.

• The Journal of the Korean dental association
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• v.17 no.1 s.116
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• pp.25-28
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• 1979

An instance of difficulty in mouth opening as around 2mm due to impingement of fractured coronoid process and zygomatic arch in 30-year-old man who had met with a traffic accident was observed and surgical operation was done. After removal of the fractured coronoid process and elevation of the depressed malunited zygomatic arch, the patient could open mouth by now about 30mm.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.4
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• pp.168-172
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• 2014

Bilateral coronoid hyperplasia causes painless progressive trismus, resulting from coronoid process impingement on the posterior aspect of the zygomatic bone. The etiology of coronoid hyperplasia is unclear, with various theories proposed. An endocrine stimulus, increased temporalis activity, trauma, genetic inheritance and familial occurrence have all been proposed, but no substantive evidence exists to support any of these hypotheses. Multiplanar reformatting of axial scans and 3-dimensional reconstruction permit precise reproduction of the shape and size of the coronoid and malar structures, and relationships of all structures of the temporal and infratemporal fossae. This case shows remarkably increased mouth opening by coronoidectomy in a patient who complained of trismus due to hyperplasia of coronoid process.

• Archives of Craniofacial Surgery
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• v.23 no.3
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• pp.111-118
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• 2022

Background: Although the zygomatic arch is an important structure determining facial prominence and width, no consensus exists regarding the classification of isolated zygomatic arch fractures, and the literature on this topic is scarce. To date, five papers have subdivided zygomatic arch fractures; however, only one of those proposed classifications includes the injury vector, although the injury vector is one of the most important factors to consider in fracture cases. Furthermore, the only classification that does include the injury vector is too complicated to be suitable for daily practice. In addition, the existing classifications are clinically limited because they do not consider greenstick fractures, nondisplaced fractures, or coronoid impingement. In the present study, we present a rearrangement of the previously published classifications and propose a modified classification of isolated zygomatic arch fractures that maximizes the advantages and overcomes the disadvantages of previous classification systems. Methods: The classification criteria for isolated zygomatic arch fractures described in five previous studies were analyzed, rearranged, and supplemented to generate a modified classification. The medical records, radiographs, and facial bone computed tomography findings of 134 patients with isolated zygomatic arch fractures who visited our hospital between January 2010 and December 2019 were also retrospectively analyzed. Results: We analyzed major classification criteria (displacement, the force vector of the injury, V-shaped fracture, and coronoid impingement) for isolated zygomatic arch fracture from the five previous studies and developed a modified classification by subdividing zygomatic arch fractures. We applied the modified classification to cases of isolated zygomatic arch fracture at our hospital. The surgery rate and injury severity differed significantly from fracture types I to VI. Conclusion: Using our modified classification, we could determine that both the injury force and the injury vector meaningfully influenced the surgery rate and the severity of the injuries.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.2
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• pp.180-185
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• 1995

TMJ ankylosis is classified with true and false type. A true ankylosis is defined as any condition that produces fibrous or bony adhesions between the articular surfaces of the temporomandibular joint. The main causes of true ankylosis are trauma or infection. A false ankylosis results from pathologic conditions outside the joint that limit mobility of the mandible such as myogenic disorders, coronoid impingement or rare direct bony fusion between maxilla and mandible. The treatment of choice of TMJ ankylosis is surgical intervention. We experienced the male patient with complete mouth opening limitation since 45 years before. This patient has true TMJ ankylosis and rare bony synostosis between maxilla and mandible in the right posterior region. We performed surgical intervention and had a favorable result.