Synchronous High-Grade Squamous Intraepithelial Lesion of the Fimbria of the Fallopian Tube in a 51-Year-Old Woman with Invasive Squamous Cell Carcinoma of the Uterine Cervix.

Primary squamous cell carcinoma or squamous intraepithelial lesion of the fallopian tube is a very rare finding with only a small number of cases worldwide. We describe the case of a 51-year-old woman, undergoing an abdominal hysterectomy after the diagnosis of an HPV-associated invasive squamous cell carcinoma of the uterine cervix with the unexpected detection of an HPV16-positive high-grade squamous intraepithelial lesion of the fimbria of the right fallopian tube in the resection specimen. The finding of an isolated, HPV-associated squamous intraepithelial lesion in the fallopian tube raises the question of a de novo development in this body compartment (after exclusion of a continuous metastatic spread from the uterine cervix) by taking a virus-associated field effect into account and should encourage the inclusion of this possibility when examining the fallopian tube in a routine setting.

In vitro performance of CAD/CAM and conventional removable dentures.

AIM: Innovations in CAD/CAM technology and materials science offer new methodologies for removable prosthodontics. As clinical data are still rare, in vitro performance of both CAD/CAM and comparable conventional materials may help to estimate the clinical outcome. MATERIALS AND METHODS: Specimens (n = 8 per group) from teeth (CediTEC, SR VivodentCAD, Vitapan), base materials (V-Print dentbase, IvoBase CAD, Paladur), adhesives (CediTEC Primer/Adhesive, IvoBase CAD Bond), and a fully printed specimen (Try-In) were created. All specimens underwent thermal cycling and mechanical loading (TCML): 1,200,000 × 50 N; 2x3000 x 5°C/55°C; H2O. Surviving specimens were loaded to fracture. Statistical tests used were the Shapiro-Wilk test and the Kaplan-Meier survival, with the level of significance set to α = 0.05. RESULTS: Mean loading cycles until failure varied between 100 and 621,667 cycles. Up to five specimens per group failed during TCML. With one exception, all specimens of the entirely CAD/CAM-fabricated group survived TCML. The log-rank (Mantel-Cox) test showed significantly different (P = 0.000) loading cycles between the systems (chi-square test: 28,247; degree of freedom: 8). Failure of the dentures during TCML was characterized by failure of the denture base (2x), denture tooth (13x), mixed base/tooth (3x) or adhesive between base and tooth (1x). CONCLUSION: TCML and fracture testing showed different aspects of denture tooth restoration. The results indicated no correlation between fracture force, fracture pattern, and survival cycles. Denture teeth (milled, heat-pressed), bases (milled, printed, pressed), and primer should be matched up to optimize the performance of dentures.

A holistic approach for suppression of COVID-19 spread in workplaces and universities.

As society has moved past the initial phase of the COVID-19 crisis that relied on broad-spectrum shutdowns as a stopgap method, industries and institutions have faced the daunting question of how to return to a stabilized state of activities and more fully reopen the economy. A core problem is how to return people to their workplaces and educational institutions in a manner that is safe, ethical, grounded in science, and takes into account the unique factors and needs of each organization and community. In this paper, we introduce an epidemiological model (the "Community-Workplace" model) that accounts for SARS-CoV-2 transmission within the workplace, within the surrounding community, and between them. We use this multi-group deterministic compartmental model to consider various testing strategies that, together with symptom screening, exposure tracking, and nonpharmaceutical interventions (NPI) such as mask wearing and physical distancing, aim to reduce disease spread in the workplace. Our framework is designed to be adaptable to a variety of specific workplace environments to support planning efforts as reopenings continue. Using this model, we consider a number of case studies, including an office workplace, a factory floor, and a university campus. Analysis of these cases illustrates that continuous testing can help a workplace avoid an outbreak by reducing undetected infectiousness even in high-contact environments. We find that a university setting, where individuals spend more time on campus and have a higher contact load, requires more testing to remain safe, compared to a factory or office setting. Under the modeling assumptions, we find that maintaining a prevalence below 3% can be achieved in an office setting by testing its workforce every two weeks, whereas achieving this same goal for a university could require as much as fourfold more testing (i.e., testing the entire campus population twice a week). Our model also simulates the dynamics of reduced spread that result from the introduction of mitigation measures when test results reveal the early stages of a workplace outbreak. We use this to show that a vigilant university that has the ability to quickly react to outbreaks can be justified in implementing testing at the same rate as a lower-risk office workplace. Finally, we quantify the devastating impact that an outbreak in a small-town college could have on the surrounding community, which supports the notion that communities can be better protected by supporting their local places of business in preventing onsite spread of disease.

Machine-driven simulation of removing luting agent remnants from implant surfaces: An investigator-independent assessment of cleaning protocols.

INTRODUCTION: To simulate removing luting agent remnants from crowns fixed onto implant-abutment analogs using a standardized machine-driven protocol including a scaler and air polishing or sonic. MATERIAL AND METHODS: A motor-driven device was constructed that controlled the rotational speed of the specimens, machining distance, contact pressure, and working time. A standardized layer of cement (Provicol, VOCO; Cuxhaven, G; Ketac Cem, 3MEspe; Seefeld, G; or Rely X Unicem, 3MEspe, Seefeld, G) was placed onto the finishing line of the crowns luted onto titanium-abutment analogs. The cement layer was scaled with a fresh titanium scaler maneuvered by the motor-driven device and treated with air polishing or sonic. Protocol 1: Scaling only for 20s, 40s, or 60s; n=20; protocol 2: 40s of scaling plus 20s of air polishing; protocol 3: 20s of scaling plus 40s of air polishing; protocol 4: 20s of scaling plus 40s of sonic; protocol 5: 40s of scaling plus 20s of sonic; protocols 2-5: n=10. Cement remnants were counted digitally as "percentage of remnants". STATISTICS: mean, standard deviation, Bonferroni post hoc tests; α=0.05. RESULTS: Ketac Cem was easily removed by scaling only and Provicol by scaling and air polishing, but the self-adhesive resin composite cement Rely X Unicem was not removable with the device. Only remnants of Provicol could be significantly reduced by further treatment after scaling (p<0.001). CONCLUSION: The presented motor-driven device enables reproducible investigations of various cleaning protocols and is thus useful to create an overview of cleaning protocols needed for the different types of cement.

Pilot in-vitro study on insertion/removal performance of hand-cast, milled and 3D printed splints.

OBJECTIVES: The aim of this in-vitro pilot study was to establish a splint testing method and compare insertion/removal performance of dental splints. MATERIALS AND METHODS: 56 identical lower jaw splints (n = 8 per group) were manufactured from 2x methacrylate (MA) hand-cast (reference material), deep-drawn Polyethyleneterephthalate, combined deep-draw MA hand-cast, 2x CAD/CAM-milled MA and 3D-printed MA systems. After 10 days water storage (37 °C), cyclic pull-off and insertion performance on a metal jaw was investigated. Statistics; Shapiro-Wilk-test, one-way-ANOVA; post-hoc-Bonferroni, Kaplan-Meier-survival, α = 0.05. RESULTS: Mean insertion/pull-off cycles varied significantly (p = 0.000) between 864 cycles (MA) and 202640 cycles (Deep Draw MA). Fracture of the splints was characterized by brittle individual fractures in the 31-34 region and most fractures in region 35 (44 of 56 splints). Finite element analysis confirmed the type and location of failure. CONCLUSIONS: Deep-draw, cast methacrylate and combined systems showed longer insertion/pull-off system cycles in comparison to printed or milled splints. Insertion/pull-off performance showed differences between the tested splint systems and indicates the influence of the processing. CLINICAL RELEVANCE: The presented in-vitro test allowed for estimating the clinical insertion/pull-off performance of dental splints.

Potential Role of MRI Imaging for Myofascial Pain: A Scoping Review for the Clinicians and Theoretical Considerations.

The most common cause of chronic musculoskeletal pain is chronic myofascial pain syndrome (MPS). MPS often presents with increased muscle stiffness, and the myofascial trigger point (MTrP). Imaging modalities have been used to identify the MTrP, but their role in the detection and diagnosis of MPS remains unclear. The purpose of this review was to identify evidence in literature for the use of imaging in the role of classifying and explaining the physiology of MTrPs. Since few imaging techniques have been performed on MTrPs, we explored the imaging techniques that can effectively image complex skeletal muscle microstructure, and how they could be used. As part of a scoping review, we conducted a systematic search from three medical databases (CINAHL, EMBASE and MEDLINE) from year to year to analyze past MTrP imaging, as well as analyzing imaging techniques performed on the microstructure of muscle. Previously, ultrasound has been used to differentiate active, latent MTrPs, but these studies do not adequately address their underlying anatomical structure. MRI remains the standard method of imaging skeletal muscle. The existing MRI literature suggests that the DTI technique can quantify muscle injury, strain, and structure. However, theoretically, HARDI and DKI techniques seem to provide more information for complex structural areas, although these modalities have a disadvantage of longer scan times and have not been widely used on skeletal muscle. Our review suggests that DTI is the most effective imaging modality that has been used to define the microstructure of muscle and hence, could be optimal to image the MTrP. HARDI and DKI are techniques with theoretical potential for analysis of muscle, which may provide more detailed information representative of finer muscle structural features. Future research utilizing MRI techniques to image muscle are necessary to provide a more robust means of imaging skeletal muscle and the MTrP.

Quantitative response of healthy muscle following the induction of capsaicin: an exploratory randomized controlled trial.

BACKGROUND: Myofascial pain syndrome (MPS) is a prevalent chronic pain disorder primarily characterized by myofascial trigger points (MTrPs). There is limited knowledge on the pathophysiology and mechanisms underlying MTrP and its development. Research has previously demonstrated the identification of MTrPs using ultrasound and vibration sonoelastography, although there is some contradictory evidence regarding if MTrPs present as hyper or hypoechoic regions. Electromyography (EMG) investigations of MTrP have demonstrated that MTrPs are usually located proximal to innervation zones where the peak surface EMG signals are obtained from. Central sensitization has been proposed as the primary mechanism underlying MTrP development. Central sensitization is associated with hyperexcitability of neuronal responses to normal or noxious stimuli. There is a need for a study that measures ultrasound image textural changes and motor unit activity responses in the muscle following sensitization. The purpose of this study is to determine whether sensitizing healthy muscle using capsaicin induces a regional change in image texture variables within the specific and surrounding muscles, as well as the motor unit frequency and amplitude changes that accompany them. This is an exploratory trial that aims to provide preliminary evidence on whether central sensitization is a direct cause of taut band and MTrP development. METHODS: Ethical approval was obtained from the University Health Network (UHN) Research Ethics Board. This proposed study is a single centered, factorial, randomized placebo-controlled trial with two independent variables, depth of capsaicin application and dose of capsaicin, for a total of six treatment arms and three control treatment groups. DISCUSSION: This will be the first study that assesses the B-mode ultrasound image texture of induced sensitized muscles and will provide more evidence on muscle motor unit activity and regional changes of central sensitization. Findings from this study may support one of few hypotheses proposed delineating the involvement of central sensitization in the development of trigger points. TRIAL REGISTRATION: National Institutes of Health ClinicalTrials.gov NCT03944889 . Registered on May 07, 2019.

Effect of Neighbourhood Size in Entropy Mapping of Ultrasound Images.

Image filtering is a technique that can create additional visual representations of the original image. Entropy filtering is a specific application that can be used to highlight randomness of pixel grayscale intensities within an image. These image map created from filtering are based on the number of surrounding neighbourhood of pixels considered. However, there is no standard procedure for determining the correct "neighbourhood size" to use. We investigated the effects of neighbourhood size on the entropy calculation and provide a standardized approach for determining an appropriate neighbourhood size in entropy filtering in a musculoskeletal application. Ten healthy subjects showing no symptoms related to neuromuscular disease were recruited and ultrasound images of their trapezius muscle were acquired. The muscle regions in the images were manually isolated and regions of interest with varying neighbourhood sizes (increasing by 2 pixels) from 3x3 to 61X61 pixels were extracted. The entropy, relative signal entropy over noise entropy, statistical effect size as well as the percentage change of the effect size and instantaneous slope of the effect size was examined. The analysis showed that a neighbourhood size within the range of 21-25 pixels provides the maximum amount of information gained and coincides with a percentage change of the effect size of less than 5% and instantaneous slopes < 0.05.

Fatigue and wear behaviour of zirconia materials.

OBJECTIVES: Comparison of in-vitro fatigue and wear performance of 3Y-, 4Y-, 5Y-TZP and lithiumdisilicate ceramic, multilayer/monolayer 4Y-TZP and variation of wall thickness at 5Y-TZP. METHOD AND MATERIALS: Crowns (n = 96; 6 groups à 16) were made of 3Y-TZP-LA, 4Y-TZP (multilayer and monolayer), 5Y-TZP (0,5mm/1 mm wall thickness) and lithiumdisilicate. 8 per group were stored in water (24hrs), 8 underwent TCML (1.200.000 × 50N; 2x3000x5°/55 °C; H2O, 2min cycle). Fracture force was determined by static loading (v = 1 mm/min, steel sphere with tin foil, diameter = 12 mm). Pin-on-block wear test was performed (steatite antagonist d = 3 mm; 50N, 120,000 cycles, 1.2Hz, lateral motion: 1 mm, antagonist lift: 1 mm, n = 8). Roughness, wear depth [µm] and antagonist wear were determined (3-D-laser-microscope, KJ3D, Keyence, J). STATISTICS: one-way-ANOVA; Bonferroni-post-hoc-test; α = 0.05. RESULTS: Fracture forces varied between 1211N (5Y,TCML) and 3952N (4Y-Mult,TCML). Individual significant differences (p ≤ 0.025) were found between materials. Increase of wall thickness (5Y; 0.5 mm/1.0 mm) lead to a non-significant (p ≥ 0.442) increase of fracture force. 4Y and 4Y-multilayer zirconia showed no significantly different (p ≥ 0.073) fracture forces. Zirconia mean wear (3Y:10.0 ± 3.9 µm, 4Y:19.8 ± 3.8 µm, 5Y:10.9 ± 6.8 µm) was not significantly (p = 1.000) different. Lithiumdisilicate ceramic (149.3 ± 45.4 µm) and human enamel (434.2 ± 131.3 µm) provided significantly (p ≤ 0.002) higher wear. Antagonistic wear against lithiumdisilicate (17.5 ± 3.9%) and human enamel (6.7 ± 3.0%) was significantly (p ≤ 0.007) lower than against zirconia (4Y:31.9 ± 8.0% - 5Y:27.6 ± 5.8%). CONCLUSION: Fracture force of 5Y-TZP differs from 4- or 3-Y-TZP. Mechanical characteristics and dimensional requirement of 5Y-TZP are comparable to lithiumdisilicate. Mono- or multilayer 4Y-TZP provided comparable fracture forces. Wear was comparable between zirconia systems and lower in comparison to lithiumdisilicate or enamel.

Machine Learning Diagnostic Modeling for Classifying Fibromyalgia Using B-mode Ultrasound Images.

Fibromyalgia (FM) diagnosis remains a challenge for clinicians due to a lack of objective diagnostic tools. One proposed solution is the use of quantitative ultrasound (US) techniques, such as image texture analysis, which has demonstrated discriminatory capabilities with other chronic pain conditions. From this, we propose the use of image texture variables to construct and compare two machine learning models (support vector machine [SVM] and logistic regression) for differentiating between the trapezius muscle in healthy and FM patients. US videos of the right and left trapezius muscle were acquired from healthy (n = 51) participants and those with FM (n = 57). The videos were converted into 64,800 skeletal muscle regions of interest (ROIs) using MATLAB. The ROIs were filtered by an algorithm using the complex wavelet structural similarity index (CW-SSIM), which removed ROIs that were similar. Thirty-one texture variables were extracted from the ROIs, which were then used in nested cross-validation to construct SVM and elastic net regularized logistic regression models. The generalized performance accuracy of both models was estimated and confirmed with a final validation on a holdout test set. The predicted generalized performance accuracy of the SVM and logistic regression models was computed to be 83.9 ± 2.6% and 65.8 ± 1.7%, respectively. The models achieved accuracies of 84.1%, and 66.0% on the final holdout test set, validating performance estimates. Although both machine learning models differentiate between healthy trapezius muscle and that of patients with FM, only the SVM model demonstrated clinically relevant performance levels.

Radiotherapy for osteoarthritis-an analysis of 295 joints treated with a linear accelerator.

PURPOSE: Osteoarthritis is a common disease, with a prevalence of symptomatic disease of 8.9%. One treatment option is radiotherapy. Most published samples were treated with an orthovoltage technique or with a telecobalt device. A lot of radiotherapy institutions are nowadays using linear accelerators for treatment of osteoarthritis. There is a discussion on whether the treatment results achieved with a linear accelerator are comparable to those with the orthovoltage technique. The aim of this study is to analyze the results of radiotherapy for osteoarthritis with a linear accelerator and compare the results with reference to different joints. MATERIALS AND METHODS: The analysis was performed in patients of two German radiotherapy institutions and included 295 irradiated joints. Pain was documented with the numeric rating scale (NRS). Evaluation of the NRS was done before and directly after each radiation therapy course as well as for the follow-up of 24 months. The median age of the patients was 65 years, with 39.0% male and 61.0% female patients. Most frequently, osteoarthritis of the knee (34.6%) or the finger (15.9%) was treated. RESULTS: We could find a significant response to radiotherapy. Median pain for the whole sample was 7 on the NRS before radiotherapy, 4 after 6 weeks, and 3 after 12 and 24 months. The percentage of patients with 0 or 1 on the NRS was 33.8% 12 months after radiotherapy. All investigated subgroups had a significant reduction of pain. CONCLUSION: Radiotherapy of osteoarthritis with a linear accelerator is an effective treatment which is very well tolerated. All analyzed subgroups show a good response to radiotherapy for at least 24 months. Orthovoltage therapy seems to be superior to treatment with a linear accelerator in a case-related analysis of the published samples. Further investigations should be performed for a definitive answer to this question.

Effect of cervical manipulation on vertebral artery and cerebral haemodynamics in patients with chronic neck pain: a crossover randomised controlled trial.

OBJECTIVE: It is hypothesised that cervical manipulation may increase the risk of cerebrovascular accidents. We aimed to determine whether cervical spine manipulation is associated with changes in vertebral artery and cerebrovascular haemodynamics measured with MRI compared with neutral neck position and maximum neck rotation in patients with chronic neck pain. SETTING: The Imaging Research Centre at St. Joseph's Hospital in Hamilton, Ontario, Canada. PARTICIPANTS: Twenty patients were included. The mean age was 32 years (SD ±12.5), mean neck pain duration was 5.3 years (SD ±5.7) and mean neck disability index score was 13/50 (SD ±6.4). INTERVENTIONS: Following baseline measurement of cerebrovascular haemodynamics, we randomised participants to: (1) maximal neck rotation followed by cervical manipulation or (2) cervical manipulation followed by maximal neck rotation. The primary outcome, vertebral arteries and cerebral haemodynamics, was measured after each intervention and was obtained by measuring three-dimensional T1-weighted high-resolution anatomical images, arterial spin labelling and phase-contrast flow encoded MRI. Our secondary outcome was functional connectivity within the default mode network measured with resting state functional MRI. RESULTS: Compared with neutral neck position, we found a significant change in contralateral blood flow following maximal neck rotation. There was also a significant change in contralateral vertebral artery blood velocity following maximal neck rotation and cervical manipulation. We found no significant changes within the cerebral haemodynamics following cervical manipulation or maximal neck rotation. However, we observed significant increases in functional connectivity in the posterior cerebrum and cerebellum (resting state MRI) after manipulation and maximum rotation. CONCLUSION: Our results are in accordance with previous work, which has shown a decrease in blood flow and velocity in the contralateral vertebral artery with head rotation. This may explain why we also observed a decrease in blood velocity with manipulation because it involves neck rotation. Our work is the first to show that cervical manipulation does not result in brain perfusion changes compared with a neutral neck position or maximal neck rotation. The changes observed were found to not be clinically meaningful and suggests that cervical manipulation may not increase the risk of cerebrovascular events through a haemodynamic mechanism. TRIAL REGISTRATION NUMBER: NCT02667821.

Performance of resin materials for temporary fixed denture prostheses.

This study investigated the handling properties and clinical performance of two commercially available resin materials with slight differences in filler composition for the fabrication of fixed interim restorations. In a dental university setting, patients requiring prosthetic treatment were supplied with fixed interim restorations fabricated from two commercially available resin materials. To clarify the handling properties of the resin materials, dentists and undergraduate students completed a questionnaire. Prior to insertion of the definitive restoration, the interim restorations were analyzed by calibrated examiners using a modification of the United States Public Health Service criteria. Eighty-two fixed interim restorations with a mean clinical service period of 44.5 (±28.3) days were included, including 39 single crowns, 30 fixed denture prostheses, 10 blocked crowns, and 3 partial coverage restorations. No significant differences between the two materials in the rating of their handling properties were identified, with the exception of the parameter "surface". Failures due to fractures were observed in 13% of the interim restorations. No significant differences between the materials in the rating of the clinical performance were identified. These results indicate that slight changes in the filler composition of commercial formulations account for few differences in handling properties and clinical performance.

Automatic ROI Placement in the Upper Trapezius Muscle in B-mode Ultrasound Images.

Research involving B-mode ultrasound imaging often requires user defined regions of interest (ROIs) for analysis, traditionally drawn/selected by a trained operator. This manual process is incredibly time consuming and subjective. Here, we propose a fast and simple method of detecting the average location of aponeurosis layers in ultrasound images of the upper trapezius to place a rectangular ROI for quantitative image analysis. A total of 56 B-mode ultrasound images were analyzed, where rectangular ROIs were manually placed in the skeletal muscle by two trained operators. Interoperator agreement was determined between the ROI border locations using intercorrelation coefficient (ICC). Next, our automatic algorithm was applied (image thresholding, binary masking, and pixel intensity peak detection), estimating the mean position of both aponeurosis layers for rectangular ROI placement. The automatic estimation method was compared with the manual (visual) method by various statistics ( t test, linear correlation, Bland-Altman plot). The performance was also evaluated under additive noise conditions (Speckle). Finally, agreement of the overlapping ROI area between the manual and automatic methods was also computed. Performance of the automatic method compared with manual placement was excellent for both the superficial and deep ROI borders, performing consistently even with additive noise (error <0.674 ± 1.69 mm). Manual measurements indicated excellent consensus (ICC = 0.902) between operators. The overlapping area between the manual and automatic measurements demonstrated good agreement (90.65 ± 11.3%). With constraints, our method is robust even under large levels of noise addition making the automatic algorithm an acceptable replacement for manual ROI placement in the upper trapezius.

Feasibility of a Support Vector Machine Classifier for Myofascial Pain Syndrome: Diagnostic Case-Control Study.

OBJECTIVES: Myofascial pain syndrome (MPS) is the most common cause of chronic pain worldwide. The diagnosis of MPS is subjective, which has created a need for a robust quantitative method of diagnosing MPS. We propose that using a support vector machine (SVM) along with ultrasound (US) texture features can differentiate between healthy and MPS-affected skeletal muscle. METHODS: B-mode US video data were collected in the upper trapezius muscle of healthy (29) participants and patients with active (21) and latent (19) MPS, using an acquisition method outlined in previous works. Regions of interest were extracted and filtered to obtain a unique set of 917 images where texture features were extracted from each region of interest to characterize each image. These texture features were then used to train 4 separate binary SVM classifiers using nested cross-validation to implement feature selection and hyperparameter tuning. The performance of each kernel was estimated on the data and validated through testing on a final holdout set. RESULTS: The radial basis function kernel classifier had the greatest Matthews correlation coefficient performance estimate of 0.627 ± 0.073 (mean ± SD) along with the largest area under the curve of 91.0% ± 3.0%. The final holdout test for the radial basis function classifier resulted in 86.96 accuracy, a Matthews correlation coefficient of 0.724, 88% sensitivity, and 86% specificity, validating our earlier performance estimates. CONCLUSIONS: We have demonstrated that specific US texture features that have been used in other computer-aided diagnostic literature are feasible to use for the classification of healthy and MPS muscle using a binary SVM classifier.

The morphological variations of the lateral pterygoid muscle: A systematic review.

BACKGROUND: The lateral pterygoid muscle (LPM) has been described in many anatomical and functional studies. The morphology of the LPM is still under debate because of its deep location in the infratemporal fossa and the difficulties to approach this area with different anatomical methods. Although it has been generally accepted that this muscle is mainly composed of two separate parts, other forms have been described in the past. OBJECTIVES: To conduct a systematic literature review regarding the anatomy and variations of the LPM. METHODS: We included studies published in English, German or French employing anatomical and imaging methods or a combination of the two methods. The cadavers used in the dissections had to be human and without any pathological alterations. Studies were only included when focusing on the anatomy of the LPM or its morphological variations or when taking the frequency of variations into account. We searched 26 biomedical databases including MEDLINE, EMBASE, BIOSIS Previews and Science Citation Index Expanded (part of Web of Science) through October 2014. The review was followed by the dissection of a hemisected head in two different planes. RESULTS: We identified 4279 records (2200 after deduplication) in the databases searches plus 17 articles from manual searches. 81 studies out of these articles were included in this review. 69 articles used anatomical methods, 5 imaging methods and 7 studies a combination of the two methods. 11 studies took into account that the LPM may have variations and also considered the relative frequency of each variation. The frequency of one-headed LPMs ranged between 7.7% and 26.7%, of two-headed LPMs between 61.4% and 91.1% and of three-headed LPMs between 4.0% and 35.0%. Our own dissection showed a three-headed version of the LPM. DISCUSSION: In anatomical studies, different preparation techniques seem to be the main reason for diverging results.

In-vitro performance of CAD/CAM crowns with insufficient preparation design.

PURPOSE: To compare the debonding and fracture force of different CAD/CAM composite crowns with respect to the influence of water storage (0d vs. 90d/37 °C) and types of cementation (adhesive vs. self-adhesive). METHODS: Extracted human molars were prepared with a worst-case preparation scenario providing a nonretentive design (height ~4 mm; angle ~15°) and reduced fitting (250 µm). After digitalization, 72 crowns (n = 8 per group; circular wall thickness 1.5 mm / occlusal thickness ~2.5 mm) were milled from the composites (CS, LU), one experimental composite (EX), a resin-infiltrated ceramic (VE), and a feldspar ceramic reference (VM). The crowns were adhesively bonded (Scotchbond Universal + Rely X Ultimate, 3M), and two groups (EX, VE) were additionally cemented with a self-adhesive cement (RelyX Unicem, 3M). After 90-d water storage, thermal cycling and mechanical loading (TCML) were performed. Restorations, which failed during storage or TCML, were analyzed using scanning electron microscopy, and surviving restorations were loaded to fracture. To evaluate storage effects, two materials (EX, LU) were investigated without water storage. RESULTS: CS (7×) and LU (2×) exhibited debonding during 90-d storage. LU (5×) debonded during TCML. Cement remained on the inner sides of the crowns in all cases. EX and VE survived storage and TCML without failure or debonding. Two specimens of VM exhibited cracks after TCML. Fracture forces varied between 720 N and 2155 N. Solely the results between VE and VM were not significantly different (p = 0.204). Debonding effects due to water storage were material dependent. Fracture forces in tendency (p > 0.117) were higher for self-adhesive cementation. CONCLUSIONS: Debonding and stability of CAD/CAM crowns were material dependent. Water storage affected debonding, and cementation marginally influenced performance and fracture force.

Electron tomography reveals details of the internal microstructure of desalination membranes.

As water availability becomes a growing challenge in various regions throughout the world, desalination and wastewater reclamation through technologies such as reverse osmosis (RO) are becoming more important. Nevertheless, many open questions remain regarding the internal structure of thin-film composite RO membranes. In this work, fully aromatic polyamide films that serve as the active layer of state-of-the-art water filtration membranes were investigated using high-angle annular dark-field scanning transmission electron microscopy tomography. Reconstructions of the 3D morphology reveal intricate aspects of the complex microstructure not visible from 2D projections. We find that internal voids of the active layer of compressed commercial membranes account for less than 0.2% of the total polymer volume, contrary to previously reported values that are two orders of magnitude higher. Measurements of the local variation in polyamide density from electron tomography reveal that the polymer density is highest at the permeable surface for the two membranes tested and establish the significance of surface area on RO membrane transport properties. The same type of analyses could provide explanations for different flux variations with surface area for other types of membranes where the density is distributed differently. Thus, 3D reconstructions and quantitative analyses will be crucial to characterize the complex morphology of polymeric membranes used in next-generation water-purification membranes.

In vitro performance and fracture resistance of novel CAD/CAM ceramic molar crowns loaded on implants and human teeth.

PURPOSE: To investigate the fatigue and fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic molar crowns on dental implants and human teeth. MATERIALS AND METHODS: Molar crowns (n=48; n=8/group) were fabricated of a lithium-disilicate-strengthened lithium aluminosilicate glass ceramic (N). Surfaces were polished (P) or glazed (G). Crowns were tested on human teeth (T) and implant-abutment analogues (I) simulating a chairside (C, crown bonded to abutment) or labside (L, screw channel) procedure for implant groups. Polished/glazed lithium disilicate (E) crowns (n=16) served as reference. Combined thermal cycling and mechanical loading (TC: 3000×5℃/3000×55℃; ML: 1.2×106 cycles, 50 N) with antagonistic human molars (groups T) and steatite spheres (groups I) was performed under a chewing simulator. TCML crowns were then analyzed for failures (optical microscopy, SEM) and fracture force was determined. Data were statistically analyzed (Kolmogorow-Smirnov, one-way-ANOVA, post-hoc Bonferroni, α=.05). RESULTS: All crowns survived TCML and showed small traces of wear. In human teeth groups, fracture forces of N crowns varied between 1214±293 N (NPT) and 1324±498 N (NGT), differing significantly (P≤.003) from the polished reference EPT (2044±302 N). Fracture forces in implant groups varied between 934±154 N (NGI_L) and 1782±153 N (NPI_C), providing higher values for the respective chairside crowns. Differences between polishing and glazing were not significant (P≥.066) between crowns of identical materials and abutment support. CONCLUSION: Fracture resistance was influenced by the ceramic material, and partly by the tooth or implant situation and the clinical procedure (chairside/labside). Type of surface finish (polishing/glazing) had no significant influence. Clinical survival of the new glass ceramic may be comparable to lithium disilicate.