[Patient-specific joint prothesis for ankylotic temporomandibular joints]. / Individueel vervaardigde prothesen voor ankylotische kaakgewrichten.

A 49-year-old woman who suffered from severe obstructive sleep apnea (OSA) was referred to the department of Oral-, Maxillofacial Surgery department due to progressive limitation of the mouth opening and chronic pain in both temporomandibular joints. Based on clinical and radiological examinations, the patient was diagnosed with recurrent ankylosis of the temporomandibular joints. The patient was treated with 2 patient-specific implants of the temporomandibular joint combined with a Le Fort I osteotomy, and a genioplasty including a genioglossus advancement. This treatment may have advantages for the patient such as a lower recurrence rate of ankylosis, improved maximal mouth opening, pain reduction and improved aesthetic results.

A Multiclass Classification Model for Tooth Removal Procedures.

Surprisingly little is known about tooth removal procedures. This might be due to the difficulty of gaining reliable data on these procedures. To improve our understanding of these procedures, machine learning techniques were used to design a multiclass classification model of tooth removal based on force, torque, and movement data recorded during tooth removal. A measurement setup consisting of, among others, robot technology was used to gather high-quality data on forces, torques, and movement in clinically relevant dimensions. Fresh-frozen cadavers were used to match the clinical situation as closely as possible. Clinically interpretable variables or "features" were engineered and feature selection took place to process the data. A Gaussian naive Bayes model was trained to classify tooth removal procedures. Data of 110 successful tooth removal experiments were available to train the model. Out of 75 clinically designed features, 33 were selected for the classification model. The overall accuracy of the classification model in 4 random subsamples of data was 86% in the training set and 54% in the test set. In 95% and 88%, respectively, the model correctly classified the (upper or lower) jaw and either the right class or a class of neighboring teeth. This article discusses the design and performance of a multiclass classification model for tooth removal. Despite the relatively small data set, the quality of the data was sufficient to develop a first model with reasonable performance. The results of the feature engineering, selection process, and the classification model itself can be considered a strong first step toward a better understanding of these complex procedures. It has the potential to aid in the development of evidence-based educational material and clinical guidelines in the near future.

Power chains as an alternative to steel-wire ligatures in temporary maxillomandibular fixation: a pilot study.

The aim of this study was to compare two techniques for temporary intraoperative maxillomandibular fixation (TIO-MMF) during orthognathic surgery: steel-wire ligatures versus power chains. Patients undergoing orthognathic surgery between October 2019 and March 2020 were included in a prospective cross-sectional study conducted in three participating hospitals. Data were collected using a standardized measurement form. A total of 44 patients were included, in whom TIO-MMF was applied 79 times. A statistically significant difference in intraoperative loss of stability of the segment relationship was found between steel-wire ligatures (11.4%) and power chains (0%). The mean application time of TIO-MMF differed significantly between steel-wire ligatures (99 seconds) and power chains (157 seconds) (P < 0.001). There was no statistical difference in occurrence of adverse events between the two techniques. This study found that the application of TIO-MMF with power chains is more stable compared to steel-wire ligatures. Steel-wire ligatures were significantly faster to apply, although the absolute difference (less than 1 minute) was small. Other possible advantages of the proposed technique are discussed. The results of this study suggest that power chains for the application of TIO-MMF in orthognathic surgery are a valuable alternative to steel-wire ligatures.

Metastable Nonextremal Antibranes.

We find new and compelling evidence for the metastability of supersymmetry-breaking states in holographic backgrounds whose consistency has been the source of ongoing disagreements in the literature. As a concrete example, we analyze anti-D3 branes at the tip of the Klebanov-Strassler throat. Using the blackfold formalism we examine how temperature affects the conjectured metastable state and determine whether and how the existing extremal results generalize when going beyond extremality. In the extremal limit we exactly recover the results of Kachru, Pearson, and Verlinde, in a regime of parameter space that was previously inaccessible. Away from extremality we uncover a metastable black Neveu-Schwarz five-brane (NS5) state that disappears near a geometric transition where black anti-D3 branes and black NS5 branes become indistinguishable. This is remarkably consistent with complementary earlier results based on the analysis of regularity conditions of backreacted solutions. We therefore provide highly nontrivial evidence for the metastability of antibranes in noncompact throat geometries since we find a consistent picture over different regimes in parameter space.

[Spontaneous dental abscesses in familial hypophosphatemic rickets]. / Multipele spontane odontogene abcessen bij familiaire hypofosfatemische rachitis.

Symptoms of familial hypophosphatemic rickets are growth retardation, the formation of O- or X-legs, pain of the joints, spontaneous dental abscesses, and delayed tooth eruption. The dental symptoms are predominantly attributable to the demineralization of dentin. In absence of adequate preventive measurements,familial hypophosphatemic rickets may lead to spontaneous pulpal necrosis. The prophylactic application of occlusal sealants might be effective in preventing abscess formation.