Three-Dimensional Printing Model Enhances Craniofacial Trauma Teaching by Improving Morphologic and Biomechanical Understanding: A Randomized Controlled Study.

BACKGROUND: Teaching about craniofacial traumas is challenging given the complexity of the craniofacial anatomy and the necessity for good spatial representation skills. To solve these problems, three-dimensional printing seems to be an appropriate educative material. In this study, the authors conducted a randomized controlled trial. The authors' main objective was to compare the performance of the undergraduate medical students in an examination based on the teaching support: three-dimensionally printed models versus two-dimensional pictures. METHODS: All participants were randomly assigned to one of two groups using a random number table: the three-dimensionally-printed support group (three-dimensional group) or the two-dimensionally-displayed support group (two-dimensional group). All participants completed a multiple-choice question evaluation questionnaire on facial traumatology (first, a zygomatic bone fracture; then, a double mandible fracture). Sex and potential confounding factors were evaluated. RESULTS: Four hundred thirty-two fifth-year undergraduate medical students were enrolled in this study. Two hundred six students were allocated to the three-dimensional group, and 226 were allocated to the two-dimensional group. The three-dimensionally printed model was considered to be a better teaching material compared with two-dimensional support. The global mean score was 2.36 in the three-dimensional group versus 1.99 in the two-dimensional group (p = 0.008). Regarding teaching of biomechanical aspects, three-dimensionally-printed models provide better understanding (p = 0.015). Participants in both groups exhibited similar previous student educational achievements and visuospatial skills. CONCLUSIONS: This prospective, randomized, controlled educational trial demonstrated that incorporation of three-dimensionally-printed models improves medical students' understanding. This trial reinforces previous studies highlighting academic benefits in using three-dimensionally-printed models mostly in the field of understanding complex structures.

Impacted lower third molar relationship with mandibular angle fracture complications.

INTRODUCTION: Mandibular angle fractures are very common and are associated with the highest risk of complications. The aim of this study is to evaluate the correlation between impacted lower third molar and mandibular angle fracture complications. MATERIAL AND METHODS: All patients presenting with a mandibular angle fracture and at least 2 months follow up were retrospectively included. The following complications were recorded: post-traumatic malocclusion, mouth opening limitation, inferior alveolar nerve hypoesthesia, infection, delayed union, hardware loosening. The patients were divided in two groups: impacted lower third molar or erupted/absent lower third molar. RESULTS: A total of 68 patients were included, lower third molar was impacted in 36 cases and erupted/absent in 32 cases. 40 complications were recorded in 27 patients at 2 months. No statistically significant difference could be found about malocclusion, mouth opening limitation and inferior alveolar nerve hypoesthesia. A lower rate of persistent inferior alveolar nerve hypoesthesia (p = 0.0557) in patients with impacted lower third molar (19.4%) was observed compared to patients without impacted lower third molar (40.6%). There was no occurrence of delayed union and hardware loosening in impacted lower third molar group, whereas 5 delayed unions and 4 hardware loosening were recorded in erupted/absent lower third molar group. Finally, the rate of patients with at least one of the 6 complications is significantly higher in the erupted/absent lower third molar group (17/32, 53.1%) than in the impacted lower third molar group (10/36, 27.8%), p = 0.033. DISCUSSION: The risk of overall complication is decreased when lower third molar is impacted in mandibular angle fracture. This supports the idea of a role of the impacted lower third molar in fracture reduction and stability.

Characterization of Infraorbital Nerve Sequelae After Orbital Floor or Zygomaticomaxillary Complex Fractures.

INTRODUCTION: Neurological sequelae of infraorbital nerve (ION) lesion 6 months after orbital floor or zygomaticomaxillary complex (ZMC) fractures, associated with initial ION injury, were compared according to the treatment performed and the type of fracture. The topographic and symptomatic sequelae at 6 months were described. MATERIALS AND METHODS: Patients with orbital floor or ZMC fracture associated with initial ION injury, between November 2018 and April 2020 and clinically reassessed 6 months after trauma were included. Detailed neurological symptomatology was assessed by a questionnaire. RESULTS: A total of 81 patients were included. Forty-two patients (51.8%) showed persistent neurological signs, i.e., isolated hypoesthesia in 28 patients (66.7%), isolated pain in 10 patients (23.8%) and both in 5 patients (9.5%). The most affected area was the cheek (42.8%). Thirty-eight patients (46.9%) presented associated signs, which were intermittent in 78.9% of cases. A pronounced improvement happened for 65.1% of patients and 76.7% were not or only slightly hindered in their daily activities. There were significantly more neurologic symptoms at 6 months in the surgical group than in the observational group and more in the ZMC fracture group than in the orbital floor fracture group. DISCUSSION: Neurological symptomatology was more frequent in patients treated surgically. Our results suggest the interest of a surgical decompression when orbital or ZMC fracture is associated with nerve damage but more data are needed. Neurological injury requires a careful initial clinical evaluation and regular follow-up to help patients coping, painful symptoms may benefit from specialized care.

Surgical Management of Craniomaxillofacial Features in the Otopalatodigital Spectrum Disorders.

ABSTRACT: Otopalatodigital syndrome spectrum disorders are caused by Filamin A (FLNA) gene mutations. Otopalatodigital syndrome spectrum disorders are a group of rare congenital skeletal dysplasia, with specific craniomaxillofacial features including otopalatodigital syndrome type 1 and type 2, Melnick-Needles syndrome, frontometaphyseal dysplasia, terminal osseous dysplasia with pigmentary defects. The authors describe cases of a young girl with Melnick-Needles syndrome and a young boy with frontometaphyseal dysplasia treated in the Oral and Maxillofacial Surgery Department. Both patients had FLNA gene mutation confirmed with molecular genetic analysis. The authors proposed a 4 step treatment of the malformations with good outcomes both aesthetically and functionally, without complication.

[Tumors affecting the temporomandibular joint - a literature review]. / Tumeurs de l'articulation temporomandibulaire ­ revue de la littérature.

Benign and malign tumors can affect the temporomandibular joint (TMJ) as any other articulation. Nevertheless, TMJ tumors are rare and mostly benign. Their clinical expression is varied including symptomatology similar to TMJ dysfunctional disorders, otologic or neurologic pathologies. In some cases, they remain totally asymptomatic. Hence, diagnosis is difficult since the symptomatology can be misleading with TMJ dysfunctional disorders or otologic disorders wrongly diagnosed. There is thus frequently a long delay between symptoms onset and diagnosis. The great variety of TMJ lesions explains the wide range of possible treatment modalities, mostly based on surgery. We provide here a review of the lesions originating from the TMJ. Tumoral or cystic mandibular lesion affecting the TMJ through local extension will not be discussed. Osteoma, osteoid osteoma, osteoblastoma, chondroma, osteochondroma, chondroblastoma, tenosynovial giant cell tumors, giant cell lesions, non-ossifying fibroma, hemangioma, lipoma or Langerhans cell histiocytosis are all possible diagnosis among the benign tumors found in the TMJ. Pseudotumors include synovial chondromatosis and aneurysmal bone cyst. Finally, malign tumors of the TMJ include mainly sarcomas (osteosarcoma, chondrosarcoma, synovial sarcoma, Ewing sarcoma, and fibrosarcoma), but also multiple myeloma and secondary metastases. We will review the clinical, radiological and histological aspects of each of these lesions. The treatment and the recurrence risk will also be discussed.

Lateral Pterygoid Muscle Biometric Modifications in Pterygoid Process Fractures Associated With Mandibular Fractures.

PURPOSE: Pterygoid process fractures (PPFs) are classically associated with Lefort fractures but can also be encountered in association with other facial fractures such as mandibular fractures. The aim of this study was to estimate the frequency of PPFs associated with mandibular fractures and identify factors associated with PPF. MATERIALS AND METHODS: We conducted a retrospective cross-sectional study using computed tomography scanning of patients having a mandibular fracture between November 2018 and April 2020. PPFs were classified using the classification by An et al. Volume, length, and width of both lateral pterygoid muscles have been evaluated by using an image processing software. Study population has been divided into 2 groups: fracture of pterygoid process or the absence of PPF. To evaluate the implication of lateral pterygoid muscle in the pathophysiology of PPF, we compared lateral pterygoid muscle volume, its maximal length, and width between both groups. Patients with bilateral fractures were excluded from this analysis. RESULTS: About 304 patients with at least 1 mandibular fracture have been included in this study. About 18 patients presenting an association of mandibular fracture and PPF were finally selected. About 83.33% of the patients were concerned by a fracture of the posterior part of the mandible. The PPF was classified as type IIA by the classification of An et al for 94.4% of patients. The lateral pterygoid muscle volumes were significantly larger on the side of the PPF (P = .02). However, there were no significant differences in the maximum length (P = .49) and width (P = .1) of lateral pterygoid muscle. CONCLUSIONS: Our study showed an association between mandibular fractures (mainly ipsilateral posterior) and isolated PPF through a lateral pterygoid muscle volume increase.

Use of 3D printed models in student education of craniofacial traumas.

A low-cost 3D printed model has been introduced into the oral and maxillofacial surgery teaching program of undergraduate students to improve education and mechanical comprehension of craniofacial trauma. Steps of the 3D printed haptic model building process are listed. 3D printed models of facial fractures were obtained from Data Imaging and Communications in Medicine (DICOM) data. Computed Aided Design and Manufacturing (CAD-CAM) freeware was used to create new fractures on the standard tessellation language (STL) file. 3D printed haptic model appears to be an efficient low-cost support for craniofacial trauma education of undergraduate students.

Modified Mandibular Sagittal Split Osteotomy.

INTRODUCTION: Mandibular osteotomies aim to displace the dental arch to the necessary position, ideally without limitation, while preserving inferior alveolar nerve (IAN) function. Supraforaminal osteotomies offer nerve safety but limit the extent of advancement, whereas Epker and Obwegeser-Dal Pont osteotomies enable unchallenged mandibular advancement but are associated with an inferior border notch. Here, we describe a new technique to avoid such disadvantages. TECHNICAL NOTE: The beginning of the procedure was similar to Epker's technique, with sectioning of the lingual cortex up to the level of the lingula. Sectioning of the buccal cortex was stopped 3 to 4 mm above the inferior border and then performed horizontally up to the gonial angle in total thickness. The inferior border periosteum and muscles attachments were conserved and hence, appropriately vascularized. DISCUSSION: This technique offers 4 advantages: absence of the inferior border notch, lower risk of damage to the IAN than with Epker's technique, sufficiently large bony surface to obtain bone healing as in Epker's technique, and no limitation to setback movement in contrast to Obwegeser-Dal Pont's or the supraforaminal osteotomy techniques.

Pre-operative parafunctional or dysfunctional oral habits are associated with the temporomandibular disorders after orthognathic surgery: An observational cohort study.

BACKGROUND: Temporomandibular disorders (TMDs) are frequent and disabling, and hence, preventing them is an important health issue. Combining orthodontic and surgical treatments for malocclusions has been shown to affect temporomandibular joint (TMJ) health. However, publications regarding the risk factors that predict negative TMJ outcomes after orthognathic surgery are scarce. OBJECTIVE: Present prospective cohort study was conducted to identify an association between pre-operative dysfunctional/parafunctional oral habits and the presence of TMD symptoms after orthognathic surgery. METHOD: We included 237 patients undergoing orthodontics and surgical treatment for malocclusions associated with dentofacial deformities within the Department of Oral and Maxillofacial Surgery of the University of Lille. Their parafunctional and dysfunctional oral habits were recorded through clinical examination along with the presence of TMD symptoms before and after the surgery. According to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) classification, the TMD symptoms studied were myalgia, arthralgia, disc displacement with or without reduction. RESULTS: Multivariate analysis revealed significant associations among bruxism (odds ratio [OR] 3.17 [1.066; 9.432]), lingual interposition (OR 4.241 [1.351; 13.313]), as well as primary swallowing (OR 3.54 [1.225; 10.234]) and the presence of postoperative symptoms of myalgia. Moreover, a significant association was observed between the presence of any dysfunctional oral habit and postoperative disc displacement with reduction (OR 4.611 [1.249; 17.021]). CONCLUSION: Bruxism and dysfunctional oral habits were shown to be risk factors for the presence of TMD symptoms also after combined orthodontic and surgical treatment. Treating such habits before orthognathic surgery should help prevent TMD.