## 2 Clinical Case  
After falling, a 4-year-old child had facial trauma and was referred to the First Aid Center of the Maresca Hospital Presidium in Torre del Greco, near Naples, in January 2001. He presented a chin cut that was sutured with three stitches; during this visit, no damage of the temporomandibular joint was diagnosed. About 1 year after the incident, a schoolteacher noticed the difficulty of the child while eating. Thus, the parents were suggested to go to the Orthodontic Program of the Multidisciplinary Department of Medical-Surgical and Dental Specialties of the University of Campania Luigi Vanvitelli in Naples. A full visit with occlusal and functional examinations was performed by an orthodontist. The intraoral evaluation revealed mouth opening reduced (13 mm), lateral mandibular movements of 3 mm and a protrusion of 2 mm without pain or clicking sounds in the temporomandibular joints (TMJ) (Figure 1). Figure 1: Reduced mouth opening (13 mm) at the first visit (age 5). After excluding a muscle contracture through functional exercises to decontract TMJ and masticatory muscles, a possible diagnosis of coronoid process hypertrophy was provided through bi-dimensional panoramic X-ray evaluation that showed larger and higher coronoid processes over the zygomatic arch with normal bone trabeculae in the processes. A clinical reevaluation and further radiological diagnostic examinations were performed at the age of 7. The patient was in mixed dentition and the elongation of the coronoid processes was confirmed by panoramic X-ray. Levandoski panographic analysis, described in [PERSON] et al. [7], was performed on the panoramic X-ray to measure the elongation or hypertrophy of the coronoid process through the evaluation of three reference points: condylion (Cd), gonion (Go) and koronion (Kr) [13]. The ratio of Kr-Go/Cd-Go on the right side was 1.10 and 1.09 on the left side (Figure 2). At the age of 10, the previous diagnosis was confirmed after clinical monitoring supported by a three-dimensional evaluation through CBCT and Magnetic Resonance Imaging (MRI). More in detail, CBCT scans showed bilateral enlargement of the coronoid processes and their close relationships with the anterior part of the zygomatic arches (Figure 3a-d). The MRI images confirmed a correct bilateral condyle-disk relationship. Bilateral TMJ fibrosis archyloses seemed to be revealed, differentiating CPH from chronic disk displacement without reduction (Figure 4a,b). Figure 3: (**a–d**) CBCT scans: (**a**) right side—closed mouth; (**b**) right side—open mouth; (**c**) left side–closed mouth; (**d**) left side—open mouth (age: 10 years). Figure 2: Diagram of the Levandoski panographic analysis on the panoramic X-ray. Line 1 is the maxillary vertical midline. Lines 2, 3 and 4 are perpendicular to line 1 as they cross the lower border of the symphysis of the mandible (Go\({}^{\prime}\)), the tip of the condyle (Cd\({}^{\prime}\)) and the tip of the coronoid process (Kr\({}^{\prime}\)), respectively (age 7). The patient's parents were given explanations and counseling regarding the diagnosis and treatment options. Due to the young age of the subject, only physical therapy was initiated to improve the condition of the masticatory muscles and avoid further mandibular movement reduction, mainly in mouth-opening [14; 15; 16] exercises involving active hinge opening and manual finger stretching in front of a mirror, combined with heat and massage through stretching and against-resistance exercises within painless limits. Over the years, periodical clinical checks were performed and the therapy resulted in an increased mouth opening from 13 mm to 21 mm after 1 year. This slight increase in mouth opening made daily activities easier, such as feeding and oral hygiene. After that achievement, the patient did not come to follow-ups, maybe being satisfied enough with the results obtained.