Implementing a deep learning model for automatic tongue tumour segmentation in ex-vivo 3-dimensional ultrasound volumes.

Three-dimensional (3D) ultrasound can assess the margins of resected tongue carcinoma during surgery. Manual segmentation (MS) is time-consuming, labour-intensive, and subject to operator variability. This study aims to investigate use of a 3D deep learning model for fast intraoperative segmentation of tongue carcinoma in 3D ultrasound volumes. Additionally, it investigates the clinical effect of automatic segmentation. A 3D No New U-Net (nnUNet) was trained on 113 manually annotated ultrasound volumes of resected tongue carcinoma. The model was implemented on a mobile workstation and clinically validated on 16 prospectively included tongue carcinoma patients. Different prediction settings were investigated. Automatic segmentations with multiple islands were adjusted by selecting the best-representing island. The final margin status (FMS) based on automatic, semi-automatic, and manual segmentation was computed and compared with the histopathological margin. The standard 3D nnUNet resulted in the best-performing automatic segmentation with a mean (SD) Dice volumetric score of 0.65 (0.30), Dice surface score of 0.73 (0.26), average surface distance of 0.44 (0.61) mm, Hausdorff distance of 6.65 (8.84) mm, and prediction time of 8 seconds. FMS based on automatic segmentation had a low correlation with histopathology (r = 0.12, p = 0.67); MS resulted in a moderate but insignificant correlation with histopathology (r = 0.4, p = 0.12, n = 16). Implementing the 3D nnUNet yielded fast, automatic segmentation of tongue carcinoma in 3D ultrasound volumes. Correlation between FMS and histopathology obtained from these segmentations was lower than the moderate correlation between MS and histopathology.

Diagnostic accuracy of bone SPECT and SPECT/CT imaging in the diagnosis of unilateral condylar hyperplasia: A systematic review and meta-analysis.

Imaging with bone scans plays an important role in the diagnostic path of patients with unilateral condylar hyperactivity or unilateral condylar hyperplasia (UCH). The aim of this study is to perform a systematic review of the diagnostic performance of the bone SPECT and SPECT/CT scan for the diagnosis of UCH. PubMed, SCOPUS and EMBASE were searched electronically to identify diagnostic accuracy studies that assessed the diagnostic value of bone SPECT and SPECT/CT for the diagnosis of UCH, Meta-analyses were performed with Metadisc 1.4 and 2.0. A total of 14 studies, with a total number of 887 patients, were included in the qualitative analysis and 11 studies qualified for meta-analyses. The pooled sensitivity and specificity for the SPECT scan were 0.814 (95 % CI: 0.639-0.915) and 0.774 (95 % CI: 0.655-0.861), for the SPECT/CT scan these were 0.818 (95 % CI: 0.749-0.874) and 0.901 (95 % CI: 0.840-0.945). The summary receiver operating characteristics of the SPECT scan showed an area under the curve of 0.847 (95 % CI: 0.722-0.972) and that of the SPECT/CT scan was 0.928 (95 % CI: 0.876-0.980). CONCLUSION: Both bone SPECT scan and SPECT/CT scan provide a high diagnostic accuracy for UCH. The added value of the SPECT/CT scan is questionable and given the potential disadvantages of the SPECT/CT scan, including the increased radiation dose and costs, the diagnostic modality of first choice in patients with UCH should be a SPECT scan.

The learning curve of transoral condylectomy; a retrospective analysis of 100 consecutive cases of unilateral condylar hyperplasia.

In this study, 100 consecutive scheduled transoral condylectomies for unilateral condylar hyperplasia were included. The safety and surgical performances were assessed, using the operating time, conversion rate and complication rate. The conversion rate learning curve was evaluated with a learning curve cumulative summation (LC-CUSUM). The total conversion rate was 8.0%. The LC-CUSUM for conversion signaled at the 53th procedure, indicating sufficient evidence had accumulated that the surgeon had achieved competence. For procedures 54-100, the conversion rate was 4.0%. The operating time for the transoral condylectomy was 41.5 ± 15.3 min; when a conversion was necessary, the operating time was 101.4 ± 28.3 min (p < 0.05). The estimated operating time in the post-learning phase was 37 min, this was reached after approximately 47 procedures. There was 1 major complication of a permanent inferior alveolar nerve hypoesthesia. The complication rate was not significantly decreased after the learning curve. Within the limitations of the study, it seems that transoral condylectomy for UCH is a safe procedure with several advantages over the traditional preauricular approach. Surgeons starting this procedure should be aware of the potential complications and of the learning curve of approximately 53 procedures.

Comparison of image quality of 3D ultrasound: motorized acquisition versus freehand navigated acquisition, a phantom study.

PURPOSE: Intra-operative assessment of resection margins during oncological surgery is a field that needs improvement. Ultrasound (US) shows the potential to fulfill this need, but this imaging technique is highly operator-dependent. A 3D US image of the whole specimen may remedy the operator dependence. This study aims to compare and evaluate the image quality of 3D US between freehand acquisition (FA) and motorized acquisition (MA). METHODS: Multiple 3D US volumes of a commercial phantom were acquired in motorized and freehand fashion. FA images were collected with electromagnetic navigation. An integrated algorithm reconstructed the FA images. MA images were stacked into a 3D volume. The image quality is evaluated following the metrics: contrast resolution, axial and elevation resolution, axial and elevation distance calibration, stability, inter-operator variability, and intra-operator variability. A linear mixed model determined statistical differences between FA and MA for these metrics. RESULTS: The MA results in a statistically significant lower error of axial distance calibration (p < 0.0001) and higher stability (p < 0.0001) than FA. On the other hand, the FA has a better elevation resolution (p < 0.003) than the MA. CONCLUSION: MA results in better image quality of 3D US than the FA method based on axial distance calibration, stability, and variability. This study suggests acquiring 3D US volumes for intra-operative ex vivo margin assessment in a motorized fashion.

Diagnostic performance of SPECT-CT imaging in unilateral condylar hyperplasia.

Nuclear imaging plays an important role in the diagnostic path of patients with unilateral condylar hyperplasia (UCH). The purpose of this study was to determine the performance of single-photon emission computed tomography-computed tomography (SPECT-CT) in a large group of patients with suspected UCH. This study prospectively included 156 patients with a clinical presentation of progressive mandibular asymmetry. All patients underwent 99 mTc-HDP SPECT-CT and extensive baseline and follow-up documentation. The relative activity of the ipsilateral condyle in relation to the contralateral condyle was calculated for both the mean and maximum count, and the diagnostic accuracy of different cut-off values was determined. The area under the receiver operating characteristic curve of the SPECT-CT scan was 0.892 for the mean count and 0.873 for the maximum count. The optimal cut-off of> 8% (SPECT-CT mean count) resulted in a sensitivity of 87.0% and a specificity of 88.6%. SPECT-CT showed good diagnostic performance in UCH; however the benefit of the CT scan is questionable and the potential disadvantages have to be weighed against the benefits when compared to standard SPECT scanning. When using SPECT-CT in the diagnostic path in UCH, a mean value cut-off of>8% for the relative activity between the condyles is most accurate.

Electromagnetic surgical navigation in patients undergoing mandibular surgery.

The purpose of this study was to evaluate the feasibility of electromagnetic (EM) navigation for guidance on osteotomies in patients undergoing oncologic mandibular surgery. Preoperatively, a 3D rendered model of the mandible was constructed from diagnostic computed tomography (CT) images. Cutting guides and patient specific reconstruction plates were designed and printed for intraoperative use. Intraoperative patient registration was performed using a cone beam CT scan (CBCT). The location of the mandible was tracked with an EM sensor fixated to the mandible. The real-time location of both the mandible and a pointer were displayed on the navigation system. Accuracy measurements were performed by pinpointing four anatomical landmarks and four landmarks on the cutting guide using the pointer on the patient and comparing these locations to the corresponding locations on the CBCT. Differences between actual and virtual locations were expressed as target registration error (TRE). The procedure was performed in eleven patients. TREs were 3.2 ± 1.1 mm and 2.6 ± 1.5 mm using anatomical landmarks and landmarks on the cutting guide, respectively. The navigation procedure added on average half an hour to the duration of the surgery. This is the first study that reports on the accuracy of EM navigation in patients undergoing mandibular surgery.

Evaluating the accuracy of resection planes in mandibular surgery using a preoperative, intraoperative, and postoperative approach.

In mandibular surgery, three-dimensionally printed patient-specific cutting guides are used to translate the preoperative virtually planned resection planes to the operating room. This study was performed to determine whether cutting guides are positioned according to the virtual plan and to compare the intraoperative position of the cutting guide with the resection performed. Nine patients were included. The exact positions of the resection planes were planned virtually and a patient-specific cutting guide was designed and printed. After surgical placement of the cutting guide, intraoperative cone beam computed tomography (CBCT) was performed. Postoperative CT was used to obtain the final resection planes. Distances and yaw and pitch angles between the preoperative, intraoperative, and postoperative resection planes were calculated. Cutting guides were positioned on the mandible with millimetre accuracy. Anterior osteotomies were performed more accurately than posterior osteotomies (intraoperatively positioned and final resection planes differed by 1.2±1.0mm, 4.9±6.6°, and 1.8±1.5°, respectively, and by 2.2±0.9mm, 9.3±9°, and 8.3±6.5° respectively). Differences between intraoperatively planned and final resection planes imply a directional freedom of the saw through the saw slots. Since cutting guides are positioned with millimetre accuracy compared to the virtual plan, the design of the saw slots in the cutting guides needs improvement to allow more accurate resections.

[Papillary carcinoma in a thyroglossal duct cyst; diagnostics and treatment]. / Schildkliercarcinoom in een mediane halscyste.

This is a case review of a 53-year-old female who presented with an asymptomatic thyroglossal duct cyst. Fine needle aspiration cytology was negative for malignant cells. However, CT findings showed a multilocular cyst of 4,4x2,5x4,5 cm with a solid mass of 1,8 cm and calcifications, suggestive for a thyroid carcinoma inside the thyroglossal duct cyst. A Sistrunk procedure was performed and pathology showed a papillary carcinoma inside the thryoglossal duct cyst. The coexistence of carcinomas in thyroglossal duct cysts is extremely rare, with most being papillary carcinomas. The Sistrunk procedure is often regarded as adequate, but controversies exist concerning the need for thyroidectomy and/or neck dissection. Our patient did not receive a thyroidectomy based on her patient- and tumourcharacteristics.

Utilization of a 3D printed dental splint for registration during electromagnetically navigated mandibular surgery.

PURPOSE: A dental splint was developed for non-invasive rigid point-based registration in electromagnetically (EM) navigated mandibular surgery. Navigational accuracies of the dental splint were compared with the common approach, that is, using screws as landmarks. METHODS: A dental splint that includes reference registration notches was 3D printed. Different sets of three points were used for rigid point-based registration on a mandibular phantom: notches on the dental splint only, screws on the mandible, contralateral screws (the side of the mandible where the sensor is not fixated) and a combination of screws on the mandible and notches on the dental splint. The accuracy of each registration method was calculated using 45 notches at one side of the mandible and expressed as the target registration error (TRE). RESULTS: Average TREs of 0.83 mm (range 0.7-1.39 mm), 1.28 mm (1.03-1.7 mm), 2.62 mm (1.91-4.0 mm), and 1.34 mm (1.30-1.39 mm) were found, respectively, for point-based registration based on the splint only, screws on the mandible, screws on the contralateral side only, and screws combined with the splint. CONCLUSION: For dentate patients, rigid point-based registration performs best utilizing a dental splint with notches. The dental splint is easy to implement in the surgical, and navigational, workflow, and the notches can be pinpointed and designated on the CT scan with high accuracy. For edentate patients, screws can be used for rigid point-based registration. However, a new design of the screws is recommended to improve the accuracy of designation on the CT scan.

Cervicofacial non-tuberculous mycobacterial lymphadenitis: clinical determinants of incomplete surgical removal.

In patients with non-tuberculous mycobacterial cervicofacial lymphadenitis, incomplete surgical removal of infected lymph nodes leads to delayed healing and a higher recurrence rate, with eventual spontaneous drainage through the skin. However, complete surgical removal is not always achievable due to the extent of the infected tissue and proximity to vulnerable structures, such as the facial or accessory nerve. The aim of this study was to identify the clinical determinants of the (in)ability to perform complete surgical removal. The electronic health records of patients aged 0-15 years with bacteriologically proven non-tuberculous mycobacterial cervicofacial lymphadenitis, who underwent surgical treatment and preoperative sonographic imaging, were analysed. This was a case-control study. A total of 103 patients met the inclusion criteria. Most of the infections were unilateral, submandibular, and caused by Mycobacterium avium. Multiple logistic regression analysis revealed that higher age (odds ratio 1.24, 95% confidence interval 1.04-1.47) and fistulization (odds ratio 3.15, 95% confidence interval 1.13-8.75) were significantly associated with a limited ability to surgically remove all infected tissue. However, a larger sonographic lymph node size was not significantly associated. These findings could aid clinicians when informing the parent(s)/guardian(s) of the patient preoperatively and in properly estimating the intraoperative and postoperative course.

Molecular basis of unilateral condylar hyperplasia?

Unilateral condylar hyperplasia (UCH) causes progressive asymmetry of the mandible. The aetiology of this growth disorder is unknown. A two-centre prospective study was established, and 10 consecutive adult UCH patients scheduled for high condylectomy were included. The resected condylar tissue was divided into two parts, one for regular histopathology and one for DNA extraction. A panel of eight selected overgrowth genes (AKT1, AKT3, MTOR, PIK3CA, PIK3R2, PTEN, TSC1, TSC2) were sequenced using next-generation sequencing, with coverage of a minimum 500 times in order to be able to detect low-grade mosaicisms. Subsequently, untargeted whole exome sequencing (WES) was performed to detect variants in other genes present in three or more patients. No mutation was detected in any of the overgrowth genes, and untargeted exome sequencing failed to detect any definitively causative variant in any other gene. Ten genes had a rare variant in three or more patients, but these cannot be designated as causative without additional functional studies. The hypothesis that the cause in at least some patients with UCH is a somatic mutation in a gene that controls cell growth could not be confirmed in this study.

Unilateral condylar hyperplasia in hemifacial hyperplasia, is there genetic proof of overgrowth?

Hemifacial hyperplasia (HFH) is characterized by an increase in volume of all affected tissues of half of the face. It is present at birth, subsequently grows proportionally, and stops growing before adulthood. Unilateral condylar hyperplasia (UCH) consists of progressive asymmetric growth of the mandible and develops typically in early adulthood. Both disorders have an unknown aetiology. The overgrowth limited to one body part suggests somatic mosaicism, as this has been found in other similar localized overgrowth disorders. Often this includes a variant in a gene in the (PIK3CA)/PI3K/(PTEN)/AKT1/mTOR pathway. Here we report the case of an HFH patient with asymmetry present at birth, in whom a progressive growth pattern similar to UCH subsequently occurred, causing marked mandibular asymmetry. A condylectomy was successfully performed to stop the progressive growth. Somatic mosaicism for a mutation in PIK3CA was detected in the condylar tissue. This finding might indicate that both HFH and UCH can be caused by variants in genes in the (PIK3CA)/PI3K/(PTEN)/AKT1/mTOR pathway, similar to other disorders that result in asymmetrical bodily overgrowth.

Ultrasound aids in intraoperative assessment of deep resection margins of squamous cell carcinoma of the tongue.

We wanted to find out whether ultrasound (US) can be used to assess the deep resection margins after excision of squamous cell carcinoma (SCC) of the tongue, as intraoperative feedback on their condition might help to prevent them being too close. Resected specimens of cancers of the tongue from 31 patients with SCC of the tongue were suspended in US gel and scanned with a small 5-10MHz US probe. The tumour was readily visible and US could differentiate it from muscle tissue. The margin of normal tongue musculature surrounding the tumour was measured on the US images, and the minimal resection margin was noted and compared with that reported by the histopathologist. The mean (SD) deep resection margins measured on the US images differed by 1.1 (0.9) mm from those reported by the histopathologist (Pearson's correlation coefficient: 0.79, p<0.01). The US measurements took a maximum of five minutes. It is feasible to use US to assess resection specimens of SCC of the tongue as an adjunct to existing strategies (such as frozen section analysis) to help achieve the desired deep surgical margins. The method is easy to incorporate into surgical routine as it does not take long.

[A traumatic swollen cheek]. / Een traumatische zwelling van de wang.

A 3-year-old girl was referred to a Department of Oral and Maxillofacial Surgery with a swelling in the mouth she had had for 2 weeks. The swelling followed the hard impact of a football against her face. The swelling appeared to result from an intraoral herniation of the buccal fat pad. The treatment of the herniation of fatty tissue depends on how long it has existed. If it has existed for only a short time, an attempt can be made to relocate the herniated tissue. If the swelling has existed for a longer time, a decision will be made for excision with primary closure of the mucosa.

Demographic features in Unilateral Condylar Hyperplasia: An overview of 309 asymmetric cases and presentation of an algorithm.

PURPOSE: Unilateral Condylar Hyperplasia (UCH) is an acquired deformity of the mandible, which can highly influence the symmetry of the face due to its progressive nature. It is caused by growth resembling pathology in one of the mandibular condyles. Definition as well as classification is subject to discussion. The aim of this study is to evaluate a large cohort of alleged UCH patients, and to describe the clinical characteristics, demographic features, classification and follow up. Secondly an algorithm is presented, in order to achieve uniformity in diagnosis and treatment. PATIENTS AND METHODS: From 1994 to 2014 a database of consecutive patients from 3 maxillofacial departments (Academic Medical Center, Amsterdam; VU Medical Center, Amsterdam and Spaarne Gasthuis, Haarlem) with suspected UCH was set up. Patients were referred by orthodontists, dentists, general practitioners or maxillofacial surgeons. Demographic features, bonescan outcomes, laterality, classification and follow-up were noted. Secondarily, all patients were retrospectively diagnosed by one surgeon (JWN), using available documentation. Missing data and follow-up were additionally retrieved from orthodontic offices. RESULTS: 394 asymmetric patients were evaluated. In 309 (78%) patients, the diagnosis UCH was justified and SPECT data were available. The mean age at presentation was 20.3 years (SD ± 7.7, range 9.0-54.5 years). In 48% of the patients, the bonescan was positive. 80% of these patients received surgical treatment, of which 62% were treated with a condylectomy only, 33% were treated with condylectomy plus additive corrective surgery, and 5% underwent corrective surgery only. Of the patient group without positive bonescan 42% of the patients received surgical treatment: 34% condylectomy only, 15% condylectomy plus additive corrective surgery, and 51% corrective surgery only. In total (N = 309) 96 (31%) patients underwent condylectomy as only surgical treatment and 124 (40%) patients received no surgical treatment at all. Treatment could be finalized with orthodontic treatment without further surgery in 64% and 41% respectively. 96 patients were subject to comparison of the classification as noted by the clinician and the author (JWN). In only 72% of the cases, the secondary screening was in agreement with the initial classification. CONCLUSION: Based on this study not all (active) UCH patients require corrective (orthognathic) surgery. A (transoral) partial condylectomy for active patients is recommended, with a postoperative remodeling period of 6 months with or without orthodontic treatment. Second stage correcting surgery may be necessary upon evaluation, using general orthognathic diagnostic and planning procedures. It appears difficult to classify patients reliably using the available clinical and radiological documentation. Objectivity and quantification in the diagnostic process is necessary: uniformity in documentation and parameters. The attached documentation form and UCH treatment algorithm is recommended.

Diagnosing nontuberculous mycobacterial cervicofacial lymphadenitis in children: A systematic review.

OBJECTIVES: Widespread controversy exists regarding correct diagnosing nontuberculous mycobacterial cervicofacial (NTM) lymphadenitis. This study intends to gather the available evidence with respect to diagnosing NTM cervicofacial lymphadenitis. METHODS: A review protocol was developed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)-statement (www.prisma-statement.org). A comprehensive search was performed in the bibliographic databases PubMed, Embase.com and Wiley/Cochrane Library. 10 Articles fulfilled the inclusion criteria and were included in the review. Assessing risk of bias of the articles was done using the revised Quality Assessment of Diagnostic Accuracy (QUADAS-2) tool. RESULTS: This systematic review shows that diagnostic studies of high methodological quality are scarce. Diagnostic accuracy of polymerase chain reaction (PCR), culture, skin testing, auramine staining, Ziehl-Neelsen staining, and immunodiagnostic assays was studied. Culture sensitivity proved to be 41,8%, while polymerase chain reaction has a sensitivity of 71,6%. Both methods showed a specificity of 100%. Sensitivity of Immunodiagnostic assays ranged between 87,5% and 100% and specificity between 81% and 100%. Overall sensitivity of skin tests containing purified protein derivative (PPD-S) was 70% (95% CI [62%-78%]) with an overall specificity of 94% (95% CI [88%-100%]). CONCLUSIONS: In patients with a high clinical suspicion for NTM cervicofacial lymphadenitis, a positive PPD-S skin is indicative for the diagnosis of NTM cervicofacial lymphadenitis. Either PCR or culture is necessary to confirm the diagnosis. Interferon-γ release assays with purified protein derivative stimulation appear to provide good sensitivity and specificity as a non-invasive pre-operative test, but the evidence is weak. More studies of high methodological quality are needed to validate the results of this systematic review.

Effects of sterilization on the mechanical properties of poly(methyl methacrylate) based personalized medical devices.

BACKGROUND: Nowadays, personalized medical devices are frequently used for patients. Due to the manufacturing procedure sterilization is required. How different sterilization methods affect the mechanical behavior of these devices is largely unknown. MATERIALS AND METHODS: Three poly(methyl methacrylate) (PMMA) based materials (Vertex Self-Curing, Palacos R+G, and NextDent C&B MFH) were sterilized with different sterilization methods: ethylene oxide, hydrogen peroxide gas plasma, autoclavation, and γ-irradiation. Mechanical properties were determined by testing the flexural strength, flexural modulus, fracture toughness, and impact strength. RESULTS: The flexural strength of all materials was significantly higher after γ-irradiation compared to the control and other sterilization methods, as tested in a wet environment. NextDent C&B MFH showed the highest flexural and impact strength, Palacos R+G showed the highest maximum stress intensity factor and total fracture work. CONCLUSION: Autoclave sterilization is not suitable for the sterilization of PMMA-based materials. Ethylene oxide, hydrogen peroxide gas plasma, and γ-irradiation appear to be suitable techniques to sterilize PMMA-based personalized medical devices.

Panoramic imaging is not suitable for quantitative evaluation, classification, and follow up in unilateral condylar hyperplasia.

Patients with suspected unilateral condylar hyperplasia are often screened radiologically with a panoramic radiograph, but this is not sufficient for routine diagnosis and follow up. We have therefore made a quantitative analysis and evaluation of panoramic radiographs in a large group of patients with the condition. During the period 1994-2011, 132 patients with 113 panoramic radiographs were analysed using a validated method. There was good reproducibility between observers, but the condylar neck and head were the regions reported with least reliability. Although in most patients asymmetry of the condylar head, neck, and ramus was confirmed, the kappa coefficient as an indicator of agreement between two observers was poor (-0.040 to 0.504). Hardly any difference between sides was measured at the gonion angle, and the body appeared to be higher on the affected side in 80% of patients. Panoramic radiographs might be suitable for screening, but are not suitable for the quantitative evaluation, classification, and follow up of patients with unilateral condylar hyperplasia.

Microcomputed tomographic analysis of human condyles in unilateral condylar hyperplasia: increased cortical porosity and trabecular bone volume fraction with reduced mineralisation.

Unilateral condylar hyperplasia or hyperactivity is a disorder of growth that affects the mandible, and our aim was to visualise the 3-dimensional bony microstructure of resected mandibular condyles of affected patients. We prospectively studied 17 patients with a clinical presentation of progressive mandibular asymmetry and an abnormal single-photon emission computed tomographic (SPECT) scan. All patients were treated by condylectomy to arrest progression. The resected condyles were scanned with micro-CT (18 µm resolution). Rectangular volumes of interest were selected in 4 quadrants (lateromedial and superoinferior) of the trabecular bone of each condyle. Variables of bone architecture (volume fraction, trabecular number, thickness, and separation, degree of mineralisation, and degree of structural anisotrophy) were calculated with routine morphometric software. Eight of the 17 resected condyles showed clear destruction of the subchondral layer of cortical bone. There was a significant superoinferior gradient for all trabecular variables. Mean (SD) bone volume fraction (25.1 (6) %), trabecular number (1.69 (0.26) mm(-1)), trabecular thickness (0.17 (0.03) mm), and degree of mineralisation (695.39 (39.83) mg HA/cm(3)) were higher in the superior region. Trabecular separation (0.6 (0.16) mm) and structural anisotropy (1.84 (0.28)) were higher in the inferior region. The micro-CT analysis showed increased cortical porosity in many of the condyles studied. It also showed a higher bone volume fraction, greater trabecular thickness and trabecular separation, greater trabecular number, and less mineralisation in the condyles of the 17 patients compared with the known architecture of unaffected mandibular condyles.

[Swallowing or inhaling? An instrument that disappears in the throat]. / Inslikken of aaspireren van een voorwerp dat in de keel verdwijnt.

Swallowing or inhaling a foreign object does not often happen in a dental practice. If however, an instrument disappears in the throat of a patient during dental treatment, an adequate response on the part of the oral healthcare provider is required. On the basis of 2 cases, the consequences and procedure appropriate when a foreign object disappears in the throat are discussed.