Subcutaneous emphysema is well known, but diffusion of gas into the mediastinum is not so common, particularly if it is caused by treatment of a root canal without apparent osseous fenestration or ...mucoperiostal lesions. We report a case of iatrogenic pneumomediastinum and facial emphysema after endodontic treatment. The diagnosis was confirmed by computed tomography, and the patient recovered after treatment with intravenous antibiotics and analgesia.
Abstract A case of a maxillary osteolytic tumour is described in a 9-year-old boy. Histological analysis led to an initial diagnosis of benign squamous odontogenic tumour, although this was not ...straightforward due to swelling, and cellular pseudo-malignant and non-specific signs. Because of the young age of the patient, a local surgical tumourectomy was first chosen with respect to the mixed dentition. For 10 months, the evolution was satisfactory. Then, a very aggressive tumoural recurrence with lip and palate infiltration led to doubts as to the histologic nature of the tumour. Efficient collaboration between several specialized pathologist teams finally confirmed that this was a squamous odontogenic tumour but in a very aggressive form. Radical surgery was then carried out.
Advantages to a diverging Raman amplifier Sadler, James D.; Silva, Luís O.; Fonseca, Ricardo A. ...
Communications physics,
05/2018, Letnik:
1, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
The plasma Raman instability can efficiently compress a nanosecond long high-power laser pulse to sub-picosecond duration. Although, many authors envisaged a converging beam geometry for ...Raman amplification, here we propose the exact opposite geometry; the amplification should start at the intense focus of the seed. We generalise the coupled laser envelope equations to include this non-collimated case. The new geometry completely eradicates the usual trailing secondary peaks of the output pulse, which typically lower the efficiency by half. It also reduces, by orders of magnitude, the initial seed pulse energy required for efficient operation. As in the collimated case, the evolution is self similar, although the temporal pulse envelope is different. A two-dimensional particle-in-cell simulation demonstrates efficient amplification of a diverging seed with only 0.3 mJ energy. The pulse has no secondary peaks and almost constant intensity as it amplifies and diverges.
Petawatt and exawatt class lasers worldwide Danson, Colin N.; Haefner, Constantin; Bromage, Jake ...
High power laser science and engineering,
2019, Letnik:
7
Journal Article
Recenzirano
Odprti dostop
In the 2015 review paper ‘Petawatt Class Lasers Worldwide’ a comprehensive overview of the current status of high-power facilities of
${>}200~\text{TW}$
was presented. This was largely based on ...facility specifications, with some description of their uses, for instance in fundamental ultra-high-intensity interactions, secondary source generation, and inertial confinement fusion (ICF). With the 2018 Nobel Prize in Physics being awarded to Professors Donna Strickland and Gerard Mourou for the development of the technique of chirped pulse amplification (CPA), which made these lasers possible, we celebrate by providing a comprehensive update of the current status of ultra-high-power lasers and demonstrate how the technology has developed. We are now in the era of multi-petawatt facilities coming online, with 100 PW lasers being proposed and even under construction. In addition to this there is a pull towards development of industrial and multi-disciplinary applications, which demands much higher repetition rates, delivering high-average powers with higher efficiencies and the use of alternative wavelengths: mid-IR facilities. So apart from a comprehensive update of the current global status, we want to look at what technologies are to be deployed to get to these new regimes, and some of the critical issues facing their development.
We investigate nonlocal interaction equations with repulsiveaattractive radial potentials. Such equations describe the evolution of a continuum density of particles in which they repulse (resp. ...attract) each other in the short (resp. long) range. We prove that under some conditions on the potential, radially symmetric solutions converge exponentially fast in some transport distance toward a spherical shell stationary state. Otherwise we prove that it is not possible for a radially symmetric solution to converge weakly toward the spherical shell stationary state. We also investigate under which condition it is possible for a non-radially symmetric solution to converge toward a singular stationary state supported on a general hypersurface. Finally we provide a detailed analysis of the specific case of the repulsiveaattractive power law potential as well as numerical results.
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.
Submental flap is useful for intra-oral reconstructions and reconstructions of the lower two thirds of the face. Dissection is delicate because of a difficult exposure under the lower rim of the ...mandible, numerous collateral arterial branches and the proximity of the marginal branch of the facial nerve. The aim of our work was to propose anatomical landmarks in order to facilitate the submental flap raising.
Ten bodies preserved in Biomet liquid were dissected bilaterally. The anatomic relationships between the marginal branch of the facial nerve and the mandible, the relationships of the submental artery, the amount and the location of its collateral branches were measured by means of a caliper.
The highest marginal branch observed was located 0.5 cm above the mandibular lower rim, while the lower one was located 0.6cm below this rim. The mean length measured between the facial artery at its crossing over the mandibular rim at the level of the pre-angular notch and the origin of the submental artery was 1.5cm. The average number of collateral branches was 3.6.
A skin incision made directly under the mandibular lower rim, as mentioned by some authors, may endanger the mandibular marginal branch of the facial nerve. Three positions of the submental artery in relation to the sub-maxillary gland are reported. The collateral branches are intended for gland, muscle, skin and bone. It is necessary to pay particular attention to the sub-lingual artery, an artery of big diameter that arises at 2.8cm on average from its origin and plunges towards the mouth's floor. It must not be followed at risk of clamping the thin pedicle destined to the digastric muscle. It is important to preserve the fat tissue around the submental pedicle in order to avoid venous congestion of the flap.
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 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.
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).
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.
L’évaluation préopératoire de l’envahissement osseux d’un carcinoma épidermoïde de la cavité orale reste difficile. Le but de notre étude a été de comparer la précision de l’IRM et du scanner dans la détection de l’envahissement mandibulaire des carcinomes épidermoïdes de la cavité orale, le contrôle histologique des marges servant de contrôle, et d’évaluer l’influence de cette détection sur le geste réalisé et sur les suites postopératoires.
Les patients porteurs d’un carcinome épidermoïde de la cavité orale cliniquement suspects de présenter un envahissement osseux ont été inclus rétrospectivement dans l’étude. Un radiologue sénior unique a revu l’ensemble des images scanner et IRM de manière indépendante à la recherche d’un envahissement mandibulaire. Les différents gestes chirurgicaux effectués ont été comparés en termes de durée d’hospitalisation et de la survenue de complications postopératoires.
Un envahissement mandibulaire a été diagnostiqué histologiquement chez 9 patients sur 35 (25,7 %). Ces envahissements osseux ont tous pu être diagnostiqués sur l’imagerie préopératoire, résultat en une sensibilité de 100 % tant pour l’IRM que pour le scanner. Le scanner était légèrement plus spécifique que l’IRM (respectivement 61,9 % et 57,1 %) dans la prédiction d’un envahissement osseux mais de manière statistiquement non significative (p=0,32). La spécificité du scanner et de l’IRM a été plus grande dans le groupe des patients édentés (respectivement 75 % et 62,5 %) comparé au groupe des patients dentés (53,8 % pour les 2 examens) mais sans différence statistiquement significative. La durée d’hospitalisation a été augmentée dans le groupe ayant bénéficié d’une résection segmentaire (RS) (25±14,5j) comparé au groupe ayant bénéficié d’une résection marginale (RM) (13±4,6j : p=0,004) et au groupe ayant bénéficié d’une hémi-mandibulectomie (HM) (15±7,2j ; p=0,014). La survenue de complications postopératoires, quelle qu’elles soient, a été augmentée dans le groupe RS (70 %, n=7/10 ; p=0,006) comparé aux groupes RM (8,3, n=1/12) et HM (23,1 %, n=3/13 ; p=0,04).
L’IRM et le scanner étant équivalent en ce qui concerne la détection des invasions mandibulaires, nous suggérons de privilégier l’IRM pour le bilan préopératoire des carcinomes épidermoïdes de la cavité orale. La spécificité pourrait être augmentée par l’ajout d’un PET scanner de manière à réduire le nombre d’interruptions mandibulaires inutiles.
Septic arthritis are serious infections rarely observed for the temporomandibular joint. They are mainly hematogenous or transmitted by contiguity.
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.
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.
PDF
