Staged autogenous calvarial bone grafting and dental implants placement in the management of oligodontia: a retrospective study of 20 patients over a 12-year period.

Oligodontia demands multidisciplinary management due to its repercussions on dentofacial growth. To place implants to realize implant-borne fixed denture, preimplant surgery may be necessary if bone volumes are insufficient. Our aim was to assess bone increase following autogenic bone grafting and to discuss prosthetic options. Twenty patients followed for oligodontia, who underwent bone grafting, were treated from 2008 to 2019. Transversal and vertical bone levels were measured pre- and postoperatively to assess alveolar ridge augmentation. Mean horizontal grafting increase was 4.60 mm [standard deviation (SD) 0.79 mm], mean sinus lift increase was 9.95 mm (SD 2.35 mm). Mean implants placed per patient was 9, mean implants placed on grafted site was 5 per patient. Overall implant survival rate was 100%. All patients benefited from prosthetic procedures when it was planned to perform implant-borne fixed dentures. Within the framework of a complete treatment plan (involving paediatric dentistry, dentofacial orthopaedics, oral and maxillofacial surgery, and prosthodontics), autologous bone grafting combined or not with orthognathic surgery is fully adapted to patients with oligodontia. It allows reconstruction of favourable bone volumes for placement of implants to realize implant-borne fixed dentures, with high implant survival rates and great improvements to quality of life.

TMJ related short-term outcomes comparing two different osteosynthesis techniques for bilateral sagittal split osteotomy.

OBJECTIVES: Bilateral sagittal split osteotomy (BSSO) is a morpho-functional surgery and post-surgical osteosynthesis may influence temporomandibular joint (TMJ) health. Our objective was to evaluate temporomandibular disorders (TMD) and TMJ symptoms after orthognathic surgery according to the type of osteosynthesis used in a population of patients with dentofacial deformities. MATERIALS AND METHODS: One hundred and eighty-three consecutive patients undergoing orthodontic and maxillofacial surgery treatment for correction of their malocclusion were recruited for a two-year period at Lille University Hospital. All patients had at least a mandibular BSSO using Epker's technique. Each patient was examined before and one year after orthognathic surgery. We compared osteosynthesis by miniplates fixed with monocortical screws (n=42) and the hybrid fixation with bicortical retro-molar screws used with miniplates (n=141). TMJ health was assessed by monitoring TMD signs and symptoms according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and scores obtained from the "Jaw Pain Function" questionnaire. RESULTS: There was no significant difference in pre-operative and one year post-operative RDC/TMD assessments (p≥0.91) or JPF score (p≥0.29) between the two types of osteosynthesis. CONCLUSION: There was no difference in TMJ health between the two techniques of osteosynthesis after BSSO. CLINICAL RELEVANCE: In our experience the hybrid technique fixation affords many advantages and does not influence postoperative TMD compared with osteosynthesis by miniplates.

Temporomandibular disorders in head and neck cancers: Overview of specific mechanisms and management.

Diagnosis classification system of Temporomandibular disorders (TMD) is based on the biopsychosocial model of pain. The pathogenesis is poorly understood, leading to difficulties in treating these multifactorial conditions. The predisposing factors are pathophysiological, psychological or structural processes that alter the masticatory system and lead to an increase in the risk of development of TMD. The purpose of this integrative review was then to point out the specific mechanisms of TMD in the oral oncologic context to optimize the TMJ functional results in the management of patients with oral oncologic conditions. We explored in this paper the role of Axis II assessment of the biopsychosocial model of pain, the involvement of mechanical concepts such as dental occlusion, mandibular condyle positioning and related-structures reconstruction, and the stomatognathic changes induced by radiation.

Twenty-four years of experience in management of complex mandibular fractures with low cost, custom-made mandibular external fixation: A 65-patient series.

INTRODUCTION: Ginestet introduced the first external device used to fix the mandible in 1936. In 1949, Morris introduced a biphasic fixation device. This "Joe Hall Morris fixation" design led to use of a self-crafted external fixator based on pins connected by a breathing tube filled with dental resin. The objective of this study was to present our surgical results with this device through a 65-patient series. METHODS: This retrospective study included all the patients who benefited from the self-crafted mandibular external fixator at our Oral and Maxillofacial department from 1995 to 2019. Sixty-five patients were allocated into two groups. There were 39 patients in the temporary stabilisation (TS) group and 26 in the bone healing (BH) group. Functional criteria were investigated, including mouth opening limitations and occlusal abnormalities. Aesthetic evaluation focused on skin healing, evaluated by both surgeon and patient. RESULTS: Twenty-three patients exhibited spontaneous bone healing during their immobilisation period and two patients developed a pseudoarthrosis in the BH group. Most TS group patients benefited from secondary management by bone graft, bone free flap, or distraction osteogenesis. Few complications were noted with our technique during the study period. CONCLUSION: Our self-crafted external fixation with Joe Hall Morris fixation style is a valuable option for external stabilisation of the lower third of the face.

A modified method for a customized harvest of fibula free flap in maxillofacial reconstruction.

Mandibular reconstruction using computer-aided design/computer-aided manufacturing cutting guides is currently a common procedure. However, inaccurate positioning of the cutting guide onto the fibular bone may result in osteosynthesis difficulties or imprecision in the reconstruction. A novel way to improve the stability of the cutting guides may be to add pillars in order for them to be suspended from the fibula, avoiding soft tissues interactions. We present the case of a 39-year-old male who needed mandibular reconstruction after a self-inflicted ballistic injury. We designed a customized cutting guide which included a set of 8 pillars allowing a suspension of the cutting guide 8 millimeters above the bone level. The pillars were perpendicular to one another, and allowed the operator to screw the cutting guide to the bone. The orthogonal position of the pillars enabled real stability during the osteotomies. In the operator experience, the length of the pillars was too important, and led to incomplete osteotomies, and the whole device was too bulky. However, with adaptations in the size of the pillars and the size of the whole device, this solution could be useful in cutting guide design to avoid impairments due to the soft tissues surrounding the fibula.

Improvement in quality of life after botulinum toxin injection for temporomandibular disorder.

BACKGROUND: Temporomandibular disorders (TMDs) cause chronic pain and interfere with quality of life (QoL). Botulinum toxin is one of the treatment modalities popularly used for TMDs. The primary objective of this retrospective study was to evaluate improvement in QoL after botulinum toxin injections in patients with TMD. METHODS: Twenty-eight patients diagnosed with TMD were included in this study. In accordance with the Research Diagnostic Criteria for Temporomandibular Disorders, all patients had myofascial pain. They received botulinum toxin A (BTX-A) injections in temporalis and masseter muscles. QoL was measured using a French translated version of the validated Oral Health Impact Profile-14 (OHIP-14) and a second questionnaire, which was an adaptation of the temporomandibular joint replacement QoL questionnaire (TMJ-QoL). Patients answered both questionnaires and a visual analogue scale (VAS) before the injection, at 1 month after the injection and at 3 months after the injection. Relationship between QoL and factors such as bruxism, age, sex and body mass index (BMI) were also evaluated. RESULTS: All patients reported significant improvements in QoL (OHIP-14 and TMJ-QoL) and VAS Scores at 1 and 3 months after BTX-A injections (P < 0.0001). A significant moderate positive correlation was noted between TMJ-QoL before BTX-A injections and BMI (P = 0.016). CONCLUSION: Overall, QoL in patients with TMD improved significantly at 1 and 3 months after BTX-A injections. BTX-A injection in masticatory muscles of patients with TMD can be a useful supportive therapy to control pain and improve QoL.

InhA, the enoyl-thioester reductase from Mycobacterium tuberculosis forms a covalent adduct during catalysis.

The enoyl-thioester reductase InhA catalyzes an essential step in fatty acid biosynthesis of Mycobacterium tuberculosis and is a key target of antituberculosis drugs to combat multidrug-resistant M. tuberculosis strains. This has prompted intense interest in the mechanism and intermediates of the InhA reaction. Here, using enzyme mutagenesis, NMR, stopped-flow spectroscopy, and LC-MS, we found that the NADH cofactor and the CoA thioester substrate form a covalent adduct during the InhA catalytic cycle. We used the isolated adduct as a molecular probe to directly access the second half-reaction of the catalytic cycle of InhA (i.e. the proton transfer), independently of the first half-reaction (i.e. the initial hydride transfer) and to assign functions to two conserved active-site residues, Tyr-158 and Thr-196. We found that Tyr-158 is required for the stereospecificity of protonation and that Thr-196 is partially involved in hydride transfer and protonation. The natural tendency of InhA to form a covalent C2-ene adduct calls for a careful reconsideration of the enzyme's reaction mechanism. It also provides the basis for the development of effective tools to study, manipulate, and inhibit the catalytic cycle of InhA and related enzymes of the short-chain dehydrogenase/reductase (SDR) superfamily. In summary, our work has uncovered the formation of a covalent adduct during the InhA catalytic cycle and identified critical residues required for catalysis, providing further insights into the InhA reaction mechanism important for the development of antituberculosis drugs.

Transcervical styloidectomy in Eagle's syndrome.

Eagle's syndrome is a rare disease responsible for polymorphic head and neck symptoms, often resulting in delayed diagnosis. The diagnosis of Eagle's syndrome is based on the presence of suggestive clinical signs associated with pain on palpation of the styloid process in the tonsillar fossa, a positive lidocaine test and elongation of the styloid process on 3D CT scan. The most commonly proposed curative treatment is styloidectomy, which allows complete resolution of symptoms in the great majority of cases. This procedure can be performed via a transoral approach or a transcervical approach. After briefly reviewing the embryology and anatomy of the styloid diaphragm region, the authors describe the transcervical styloidectomy technique performed in their department. This simple technique is based on anatomical imperatives designed to limit the operating time and avoid damage to neurovascular structures.

Functional and morphologic outcomes of CAD/CAM-assisted versus conventional microvascular fibular free flap reconstruction of the mandible: A retrospective study of 25 cases.

INTRODUCTION: Mandibular reconstruction using fibula free flap has been improved in the last decade with computer-aided design and computer-aided manufacturing (CAD/CAM) but any functional and aesthetic evaluation of their reattempts has been realized. Aim of this retrospective study is to compare functional and morphologic outcomes after mandibular reconstruction with fibula free flap using CAD/CAM or conventional peroperative shaping for mandible reconstruction. Moreover, we compared quality of life, patient and surgery characteristics in the two groups. PATIENTS AND METHODS: We realized a monocentric retrospective analyzed of 25 cases of unilateral mandibular reconstruction divided in two groups, using CAD/CAM (12 patient) or conventional approach (13 patients) between April 2012 and March. Functional and aesthetic measurements were performed postoperatively. RESULTS: Mouth opening, laterotrusion and protrusion of the mandible seemed to be improved in CAD/CAM group compared with conventional group but did not differ significantly. Quality of life, bite force, masticatory ability, eating and chewing satisfaction, appearance and social activity satisfaction did not differ significantly in the two groups. CONCLUSION: Even if no superiority has been established for CAD/CAM group regarding functional and aesthetic outcomes, a prospective design of future studies and transdisciplinary approach should improve our data and their interpretations. Thus, the integration of virtual planning and guided surgery is definitely of significant value and must be considered in complex maxillofacial reconstructions.

How to produce pre-shaped rigid arch bars using low-cost 3D printing technology - A technical note.

Numerous oral and maxillofacial procedures in dentate patients begin with the fixation of occlusions. While several techniques exist to perform mandibulo-maxillary fixation, many surgeons use arch bars in common practice. In cases of severe craniofacial traumas or jaw malformations, such as temporomandibular joint ankylosis, it may be impossible to use rigid arch bars. This technical note reports on the development of a technique to produce pre-shaped rigid arch bars using 3D printing technology. We take the case of a patient who presents Le Fort 1, Le Fort 2 and Le Fort 3 fractures as well as a central palatine disjunction, an angular mandibular fracture and bilateral zygomatic fractures. We specify the indications and limitations of this technique.

A conserved threonine prevents self-intoxication of enoyl-thioester reductases.

Enzymes are highly specific biocatalysts, yet they can promote unwanted side reactions. Here we investigated the factors that direct catalysis in the enoyl-thioester reductase Etr1p. We show that a single conserved threonine is essential to suppress the formation of a side product that would otherwise act as a high-affinity inhibitor of the enzyme. Substitution of this threonine with isosteric valine increases side-product formation by more than six orders of magnitude, while decreasing turnover frequency by only one order of magnitude. Our results show that the promotion of wanted reactions and the suppression of unwanted side reactions operate independently at the active site of Etr1p, and that the active suppression of side reactions is highly conserved in the family of medium-chain dehydrogenases/reductases (MDRs). Our discovery emphasizes the fact that the active destabilization of competing transition states is an important factor during catalysis that has implications for the understanding and the de novo design of enzymes.

Influence of preoperative imaging on fibula free flap harvesting.

INTRODUCTION: The fibula free flap (FFF) is the gold standard for the reconstruction of large maxillofacial defects. Magnetic resonance angiography (MRA) seems to supersede digital subtraction angiography (DSA) as the reference in preoperative evaluation, being non-invasive and having equivalent diagnostic results. The aim of this study was to assess the impact of preoperative MRA versus DSA on the viability of FFF and its success rate. MATERIAL AND METHODS: A total of 216 patients, who underwent mandibular or maxillary FFF reconstruction from January 1995 to January 2011, were retrospectively included in the study. Of them, 101 patients underwent preoperative DSA and 115 underwent MRA. Recorded criteria were as follows: age, sex, tobacco consumption, defect etiology, preoperative vascular assessment, donor-site choice and flap failure. The DSA group was compared to the MRA group. RESULTS: The harvested side was switched in 15.7% of cases with preoperative MRA versus 4% with DSA. Our success rate was higher (96.1%) with MRA than with DSA (88.1%) (P<0.05). More atherosclerotic patients (P=0.004) were diagnosed through MRA. MRA and DSA showed similar results in anatomical variation detection. CONCLUSION: MRA is less invasive and more effective in atherosclerosis detection than DSA. Therefore, donor-site switching was more frequent in the MRA group, which led to a better success rate. MRA should replace DSA as the reference in preoperative assessment.

Ameloblastoma of the jaws: Management and recurrence rate.

INTRODUCTION: Ameloblastoma is a rare, benign odontogenic tumour associated with a high recurrence rate. It accounts for 1% of all tumours of the jaws. The purpose of this study was to compare the ameloblastoma recurrence rate according to the type of treatment: radical or conservative. PATIENTS AND METHODS: All patients with a diagnosis of ameloblastoma between 1991 and 2013 were retrospectively identified in order to extract topographic, radiological, and histological data and the type of treatment: conservative (marsupialization, enucleation, curettage) or radical (segmental resection) and to compare the recurrence rate according to the type of treatment. RESULTS: Twenty-seven patients were included, managed by conservative treatment (CT) in 22 cases and radical treatment (RT) in 14 cases. The recurrence rate was 90.9% in the CT group and 9.1% in the RT group (P=0.025) with a mean follow-up of 56.2 months. DISCUSSION: The recurrence rate after conservative treatment was higher than that after radical treatment. These results are similar to those reported in the literature. The choice of treatment must be adapted to the macroscopic and histological characteristics of each tumour and to the patient.

[Temporomandibular joint septic arthritis with secondary condylar resorption]. / Arthrite septique temporomandibulaire avec résorption condylienne secondaire.

INTRODUCTION: Septic arthritis are serious infections rarely observed for the temporomandibular joint. They are mainly hematogenous or transmitted by contiguity. OBSERVATION: Our patient presents the case of an infection of the temporomandibular joint by maxillary sinusitis of dental origin further complicated by cerebral abscess and empyema. Initial treatment consisted of an endonasal and intraoral drainage, intravenous empirical antibiotic therapy, a close clinicoradiological monitoring, and rehabilitation following a long-term active physiotherapy. Furthermore, the patient reported the onset of a dental articulation disorder with a left side premature contact and right lateral open bite, corresponding to a significant left condylar resorption. DISCUSSION: This infectious disease is very rare for temporomandibular location; however, its general and functional outcome is determined by the precocity of the treatment. It is important to know the diagnosis and the associated symptoms even if they are not very specifically described. It is essential to consider the diagnosis when facing atypical pain of the temporomandibular joint associated with trismus.

[Temporomandibular joint (TMJ): Condyle hyperplasia and condylectomy]. / Articulation temporomandibulaire (ATM) : hypercondylie et condylectomie.

The mandibular condyle is a special structure. Its embryology and physiology provide to the TMJ a particular behavior that explains the occurrence of specific diseases. Condyle hyperplasia is one of these disorders. It can be explained by a dysregulation of the prechondroblast cell layer within the cartilage cap providing an increase in volume first of the condyle, then of the ramus and finally of the entire affected hemiface. Mandible deformation affects the basal bone, leading to dento-alveolar deformations related to compensation attempts. Controversies, condylectomy is performed by many surgeons. This procedure allows for the correction of some of the dento-alveolar compensations. In some cases, an additional orthognathic surgery will be required to achieve a perfect result.

Magnetic resonance imaging and computed tomography in the assessment of mandibular invasion by squamous cell carcinoma of the oral cavity. Influence on surgical management and post-operative course.

INTRODUCTION: Preoperative evaluation of the bone for invasion by oral cavity squamous cell carcinoma remains challenging. The aim of our study was to compare the accuracy of MRI and CT in detecting mandibular invasion by oral squamous cell carcinoma of the oral cavity, with histologic results as the reference standard, and to assess the influence on surgical management and post-operative course. PATIENTS AND METHODS: Patients who were clinically suspected of having bone invasion from oral cavity carcinoma were retrospectively included. A single senior radiologist reviewed MRI images and CT-scans, independently, for the presence or absence of mandibular invasion. The different surgical procedures were compared in terms of length of hospital stay and occurrence of surgical complications. RESULTS: Histological mandibular invasion occurred in 9 of 35 patients (25.7%). None of the preoperative imaging tests failed to detect bone invasion which resulted in a sensitivity of 100% for both MRI and CT. CT had slightly higher specificity than MRI (61.9% and 57.1% respectively) in predicting bone invasion, but no statistically significant difference was found (P=0.32). Specificity of CT and MRI was higher in the edentulous group (75% and 625% respectively) than in the dentate group (53.8% both), although no statistically significant difference was found. The length of hospital stay was increased in the segmental resection group (25±14.5 days) compared to the marginal resection group (13±4.6 days; P=0.004) and to the hemimandibulectomy group (15±7.2 days; P=0.014). Occurrence of post-operative complications, across all categories, was increased in the segmental resection group (70%, n=7/10; P=0.006) compared to the marginal resection group (8.3%, n=1/12) and to the hemimandibulectomy group (23.1%, n=3/13; P=0.04). CONCLUSION: MRI and CT being equivalent in detecting mandibular invasion, we suggest MRI as single imaging technique in the preoperative assessment of oral cavity SCC. Specificity could be increased if combined with PET/CT, in order to reduce the number of unnecessary mandibular interruptions.