Magnification in preclinical procedures: effect on muscle activity and angular deviations of the neck and trunk

Objectives

This study aimed to assess the effects of different magnification systems on the angular deviations of the neck and trunk and the muscle activities of the upper back and neck during preclinical cavity preparation.

Methods

This was an experimental laboratory study, with the angular deviations from the neutral positions of the neck and trunk and the activities of the bilateral upper back (the descending and ascending trapezius) and neck (sternocleidomastoid) muscles as the dependent variables. The independent variables were the different magnification systems used (Simple, Galilean, and Keplerian loupes, with direct vision as the control) and prepared teeth (teeth 16, 26, 36, and 46). A dental mannequin phantom head with artificial resin teeth was used, and Class I cavity preparations for composite resin were performed on teeth 16, 26, 36, and 46 using a 1012 round diamond bur at low speed. To analyze the angular deviations, the postures adopted during the procedure were recorded using a tripod-mounted camera positioned to provide a lateral view of the operator. A trained researcher measured the angular deviations using the software entitled "Software for Postural Assessment"-SAPO (version 0.69). Bilateral muscle activity was assessed using surface electromyography. Descriptive statistical analysis was performed, and after verifying the assumptions of normality and homoscedasticity, two-way analysis of variance and the Tukey and Games-Howell post-hoc tests were used to compare the data (α=0.05).

Results

The angular deviation from the neutral position of the neck was found to be significantly higher during cavity preparations performed with the naked eye and the Simple loupe, irrespective of the prepared tooth. With regard to tooth location, the angular deviation of the neck was significantly greater during cavity preparation on teeth 16 and 26, and the angular deviation of the trunk was significantly greater during cavity preparation on tooth 26, regardless of the magnification system used. There were significant differences in right sternocleidomastoid muscle activity between the Simple, Galilean, and Keplerian loupes, with activity being the lowest for the Galilean loupe (p = 0.008). There were no significant differences in left sternocleidomastoid muscle activity between the loupes, regardless of the prepared tooth (p = 0.077). The activities of the bilateral descending trapezius and the right ascending trapezius muscles were significantly lower when the Galilean loupe was used (p < 0.010).

Conclusion

These results suggest that the Galilean loupe resulted in lower muscle activity in the neck and back regions and that the Galilean and Keplerian loupes resulted in less angular deviations of the neck and trunk during cavity preparation.

The Successful Interdisciplinary Outcome of Blunderbuss Canal with an Open Apex Using MTA under Magnification: A Case Report

Aim and objective

The present case report aims to describe the nonsurgical management of an anterior tooth with a blunderbuss canal and an open apex using mineral trioxide aggregate (MTA) under magnification.

Background

When pulp is traumatized before root formation, it results in pulpal necrosis, due to which dentin and root formation are interrupted. As a result, the canal remains broad due to thin and fragile dentin walls leading to the open apex. Therefore, root canal treatment is a big challenge currently. In such cases, we prefer MTA apexification to form the hard tissue apical barrier, which is a foreseeable treatment and has been used as another advanced method than calcium hydroxide (CaOH2) apexification due to its superior properties.

Case description

A novel apexification technique was used by the Departments of Pediatric Dentistry and Conservative Dentistry and Endodontics for MTA placement in the central incisor with respect to 11 of a 9-year-old female patient. MTA was used to form an apical barrier using the micro-apical placement (MAP) system under a dental operating microscope (DOM). Following MTA hard set confirmation, obturation with bioceramic sealer and gutta percha with warm vertical condensation was done, followed by post-endodontic composite restoration.

Conclusion

This case describes the nonsurgical management of an open apex using MTA, MAP system, magnification, and bioceramics, which aided in the management of this endodontic enigma.

How to cite this article

Bhasin P, Saraf BG, Chauhan S, et al. The Successful Interdisciplinary Outcome of Blunderbuss Canal with an Open Apex Using MTA under Magnification: A Case Report. Int J Clin Pediatr Dent 2024;17(1):97-101.

Does cone-beam CT convex triangular field of view influence the image shape distortion of high-density materials?

OBJECTIVES

To assess the distortion of high-density materials using two CBCT devices presenting convex triangular and cylindrical fields of view (FOVs).

METHODS AND MATERIALS

Four high-density cylinders were individually placed in a polymethylmethacrylate phantom. 192 CBCT scans were acquired using the convex triangular and cylindrical FOVs of Veraviewepocs® R100 (R100) and Veraview® X800 (X800) devices. Using HorosTM's software, two oral radiologists determined the cylinders' horizontal and vertical dimensional alterations. Nine oral radiologists subjectively identified each cylinder's axial shape distortion. Statistical analysis comprised Multiway ANOVA (α = 5%), and the Kruskal-Wallis test.

RESULTS

The distortion in the axial plane was greater in the convex triangular FOVs for both devices in almost all the materials (p < 0.05). The evaluators subjectively identified a shape distortion in both FOVs for R100 device (p < 0.001), while no distortion was identified for X800 device (p = 0.620). A vertical magnification of all materials was observed in both FOVs for both devices (p < 0.05). No differences among vertical regions (p = 0.988) nor FOVs (p = 0.544) were found for the R100 device, while all materials showed higher magnification in all regions in the cylindrical FOV (p < 0.001) of the X800 device.

CONCLUSIONS

The convex triangular FOV influenced the axial distortion of the high-density materials in both devices. A vertical magnification was observed in both FOVs of both devices, but it was greater in the cylindrical FOV of the X800 device.

Under the magnifying glass: The ups and downs of rDNA copy number

The ribosomal DNA (rDNA) in Drosophila is found as two additive clusters of individual 35 S cistrons. The multiplicity of rDNA is essential to assure proper translational demands, but the nature of the tandem arrays expose them to copy number variation within and between populations. Here, we discuss means by which a cell responds to insufficient rDNA copy number, including a historical view of rDNA magnification whose mechanism was inferred some 35 years ago. Recent work has revealed that multiple conditions may also result in rDNA loss, in response to which rDNA magnification may have evolved. We discuss potential models for the mechanism of magnification, and evaluate possible consequences of rDNA copy number variation.

Surgeon's Eyes on the Relevant Surgical Target

The resolution of the naked eye has been a challenge for the neurosurgical endeavor since the very first attempts of cranial surgery, and advances have been achieved over the centuries, driven by a synergism between the application of emerging technology into the surgical environment and the expansion of the capabilities of neurosurgery. The understanding of the principles of the optical properties of lenses by Abbè (1840-1905) led to the introduction of loupes in the surgical practice, increasing the visual performance during macroscopic procedures. Modern neurosurgery began with the possibility of illumination and magnification of the surgical field as provided by the microscope. Pioneering contributions from Donaghy and Yasargil opened the way to the era of minimalism with reduction of operative corridors and surgical trauma through the adoption of the microsurgical technique. Almost at the same time, engineering mirabilia of Hopkins in terms of optics and lenses allowed for introduction of rigid and flexible endoscopes as a viable tool in neurosurgery. Nowadays, neurosurgeons are aware of and confident using effective and modern tools of visualization in their armamentarium. Herein we present a cogent review of the evolution of visualization tools in neurosurgery, with a special glimpse into the current development and future achievements.

Loupe Assisted Thyroidectomy: A Tool for Reducing Complications

The objective of this study is to assess if the use of magnification can reduce the incidence of hypocalcemia and vocal cord palsy in thyroid surgery. Data of patients who underwent total thyroidectomy (N = 50) for thyroid malignancy were analyzed retrospectively for 1 year. The patients were divided into two groups based on surgery with and without loupes. Hypocalcemia and Vocal cord palsy was assessed pre as well as post-operatively and the observations were noted. Descriptive statistics were performed to assess the proportion of the respective groups. Inferential statistics to find out the difference between the groups was done using the chi-square test. Significance level was kept at 5%. The incidence of hypocalcemia was 36.9% in the group done without loupes compared to 7.6% with loupes. The event of vocal cord injury though transient was 33% when done without loupes (p < 0.05). Magnification is crucial for the visualization of the neurovascular anatomy which is depicted in our study. Although the study includes less number of cases, it is evident that the use of loupe magnification can reduce the morbidity associated with thyroid surgery to a great extent. We recommend the use of loupe magnification during surgery whenever possible.

The Basic VRS-Effect Study: Clinical Trial Outcomes and Cost-Effectiveness of Low Vision Rehabilitation in Portugal

INTRODUCTION

The aim of this study was twofold: (1) to investigate the clinical impact of vision rehabilitation in patients with vision impairment and (2) to investigate the cost-effectiveness of a basic vision rehabilitation service in Portugal.

METHODS

The trial recruited patients diagnosed with age-related macular degeneration or diabetic retinopathy (DR) and visual acuity in the range 0.4-1.0logMAR in the better-seeing eye. Participants were randomised to one of the study arms consisting of immediate intervention and delayed intervention. The intervention included: new refractive correction, optical reading aids, in-office training and advice about modifications at home. Visual ability, health-related quality of life and costs were measured. Economic analysis was performed to evaluate whether the intervention was cost-effective. The trial compared the outcomes 12 weeks after the start in both arms.

RESULTS

Of the 46 participants, 34 (74%) were diagnosed with DR, 25 (54%) were female, and mean age was 70.08 years (SD = 8.74). In the immediate intervention arm visual ability increased a mean of 0.523 logits (SE = 0.11) (p < 0.001). Changes in the delayed intervention arm were not statistically significant (p = 0.95). Acuity in the better-seeing eye, near acuity and critical print size also improved during the study. The mean cost of the intervention was €118.79 (SD = 24.37). The incremental cost-effectiveness ratio using the EQ-5D-5L was 30,421€/QALY and 1186€/QALY when using near acuity.

CONCLUSION

The current study gives evidence of positive clinical impact of a basic vision rehabilitation intervention and shows that a basic vision rehabilitation service is cost-effective. These findings are important to clinical and rehabilitation practices and for planning vision rehabilitation services.

TRIAL REGISTRATION

Retrospectively registered, 21/01/2019. ISRCTN10894889, https://www.isrctn.com/ISRCTN10894889.

Characteristics and attitudes of general and pediatric dentists who use loupes

BACKGROUND

Dental loupes are used by dental professionals to improve visual performance, reduce eye strain and prevent musculoskeletal disorders. Data on their usage in pediatric dentistry are scarce.

STUDY DESIGN

We performed a cross-sectional survey to evaluate the approach, knowledge, and frequency of using loupes among 100 general and pediatric dentists.

RESULTS

showed that the use of loupes is significantly more prevalent among general dentists (64.3%) compared to pediatric specialists and residents (35.7%). Among dentists who reported that they do not use loupes, 63.6% were pediatric dentists and residents, and 82.5% were dentists working with children. A significantly higher percentage of dentists who self-reported as loupes users perceived that the loupes afford comfortable and stable posture, confidence while working, and contribute to the detection of tooth decay. A significantly higher percentage of dentists who self-reported as non-users of loupes (compared to loupes users), claimed that they weaken the eyes, require long adjustment, and cause discomfort.

CONCLUSION

Although the use of loupes in general dentistry is becoming more prevalent, there is still a need to raise awareness for this vision aid among pediatric dentists while promoting its advantages, to reap benefits associated with their usage.

Effect of magnification factor by Galilean loupes on working posture of dental students in simulated clinical procedures: associations between direct and observational measurements

Objectives

To determine the effect of different levels of Galilean loupe magnification on working posture as measured by compliance with ergonomic posture positions, angular deviation from the neutral position of the neck, and muscle activation in the neck and upper back region during simulated clinical conditions.

Methods

An experimental laboratory study was performed in which the dependent variables were compliance with ergonomic posture requirements while performing simulated restorative procedures in Restorative Dentistry, angular deviation from the neutral position of the neck, and muscle activation in the neck and upper back. The independent variable was the level of Galilean loupe magnification, which was tested at four levels (naked eye, 2.5× magnification, 3.0× magnification, and 3.5× magnification). The cavity preparations and Class I composite resin restorations were performed on artificial first molars on a mannequin in a dental chair. The Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP) was used for the postural analysis; as was an analysis of the angular deviation from the neutral position of the neck and surface electromyography. Working posture was recorded on video over the course of the procedure. Participants were filmed from three different angles. The Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP) assessed compliance with ergonomic posture requirements. A locally produced posture assessment software analyzed angular deviation. Surface electromyography bilaterally assessed activation of the sternocleidomastoid, descending trapezius and ascending trapezius muscles. Two-factor analysis of variance (ANOVA) and either Tukey's post-hoc test or the Games-Howell post-hoc test were performed (α = 0.05).

Results

During the cavity preparations and restorations, the use of Galilean loupes at all magnifications positively influenced working posture as measured by participants' compliance with ergonomic posture positions (p < 0.01) and neck angulation (p < 0.01); the use of these loupes did not affect muscle activation in the regions evaluated (p > 0.05).

Conclusion

The use of Galilean loupes had a positive effect on dental students' working posture during the restoration procedures performed.

Fluorescence Microscopy: A Field Guide for Biologists

Optical microscopy is a tool for observing objects, and features within objects, that are not visible to the unaided eye. In the life sciences, fluorescence microscopy has been widely adopted because it allows us to selectively observe molecules, organelles, and cells at multiple levels of organization. Fluorescence microscopy encompasses numerous techniques and applications that share a specialized technical language and concepts that can create barriers for researchers who are new to this area. Our goal is to meet the needs of researchers new to fluorescence microscopy, by introducing the essential concepts and mindset required to navigate and apply this powerful technology to the laboratory.

EMDA: A Python package for Electron Microscopy Data Analysis

An open-source Python library EMDA for cryo-EM map and model manipulation is presented with a specific focus on validation. The use of several functionalities in the library is presented through several examples. The utility of local correlation as a metric for identifying map-model differences and unmodeled regions in maps, and how it is used as a metric of map-model validation is demonstrated. The mapping of local correlation to individual atoms, and its use to draw insights on local signal variations are discussed. EMDA’s likelihood-based map overlay is demonstrated by carrying out a superposition of two domains in two related structures. The overlay is carried out first to bring both maps into the same coordinate frame and then to estimate the relative movement of domains. Finally, the map magnification refinement in EMDA is presented with an example to highlight the importance of adjusting the map magnification in structural comparison studies.

A new type of nanoscale reference grating manufactured by combined laser-focused atomic deposition and x-ray interference lithography and its use for calibrating a scanning electron microscope

Calibration of magnification and nonlinearity of scanning electron microscopy (SEM) is an essential task. In this paper, we proposed a new type of 1D grating sample fabricated by combining laser-focused atomic deposition and x-ray interference lithography as a lateral standard for calibrating SEMs. The calibrations of the grating pattern by a metrological large-range atomic force microscope indicate that the grating sample exhibits outstanding pattern uniformity that surpasses conventional samples fabricated by e-beam lithography: (1) the nonlinear deviation of the grating structures is below +/- 0.5 nm over a measurement range of 5 µm; (2) the maximal variation of the calibrated mean pitch values is lower than 0.01 nm at different locations randomly selected all over the pattern area. The proposed new sample is applied for accurately calibrating the magnification and nonlinearity of a commercial SEM, showing its advantages of easy-of-use and high accuracy. The influence of the defocus level of SEM on the calibration result is also demonstrated. This research offers a feasible solution for highly accurate SEM calibration needed for 3D nanometrology and hybrid metrology demanded in metrology of modern nanoelectronics devices and systems.

Ergonomic working posture in simulated dental clinical conditions: effect of magnification on the operator's experience

Objectives

This study observed the effect of different magnification systems on working posture and neck angulation during cavity preparation procedures according to operator's experience.

Methods

This was a laboratory study. The response variables were the neck angulation and the working posture adopted during Class I cavity preparations (N = 640) that were performed under four conditions (unaided visualization, simple loupe, Galilean loupe and Keplerian loupe). Working postures were recorded and evaluated by the Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP). The two-factor ANOVA and Games-Howell post-hoc test were performed (α = 0.05).

Results

For all treated teeth it was observed higher posture scores and lowest neck angulations while using the Galilean and Keplerian loupes (p < 0.01). No correlations were found between operator's experience and working posture (p = 0.71-0.88).

Conclusion

It can be concluded that Galilean and Keplerian loupes helped operators to maintain an ergonomic posture and lower neck angulations for all teeth and the operator's experience provided better ergonomic posture for the mandibular teeth.

Experimental evaluation of super-resolution imaging and magnification choice in single-particle cryo-EM

The resolution of cryo-EM reconstructions is fundamentally limited by the Nyquist frequency, which is half the sampling frequency of the detector and depends upon the magnification used. In principle, super-resolution imaging should enable reconstructions to surpass the physical Nyquist limit by increasing sampling frequency, yet there are few reports of reconstructions that do so. Here we directly examine the contribution of super-resolution information, obtained with the K3 direct electron detector using a 2-condenser microscope, to single-particle cryo-EM reconstructions surpassing the physical Nyquist limit. We also present a comparative analysis of a sample imaged at four different magnifications. This analysis demonstrates that lower magnifications can be beneficial, despite the loss of higher resolution signal, due to the increased number of particle images obtained. To highlight the potential utility of lower magnification data collection, we produced a 3.5 Å reconstruction of jack bean urease with particles from a single micrograph.

Efficacy of microsurgery in treatment of localized or multiple gingival recession: A systematic review

Objective

To address the clinical question whether microsurgery hold an advantage in terms of clinical and patient oriented outcome over conventional macrosurgical procedures in the treatment of gingival recession.

Material and methods

A Literature search on MEDLINE, SCOPUS, EMBASE (Excerpta Medica Database) via Ovid and Cochrane library was conducted in order to investigate clinical studies on efficacy of microsurgery in the treatment of localized or multiple gingival recession as compared to conventional macrosurgical procedures. Publications before May 2020 and grey literature was searched without any language restrictions. Primary outcome considered was change in recession depth and mean root coverage. Whereas, change in clinical attachment level, Change in keratinized tissue, patient oriented outcome like esthetics, pain and discomfort were the secondary outcome. Based on inclusion criteria ten studies were included in systematic review. Data was extracted and analyzed.

Results and conclusion

All the included studies showed improvement in the mean percentage of root coverage or mean root coverage (primary outcome) when microsurgical approach was used. Predictability of complete root coverage is better with microsurgical instrumentation but results are not statistically significant. As far as patient centered outcome is concerned, there is no evidence for recommendation of microsurgery.

Clinical applicability of gastroscopy with narrow-band imaging for the diagnosis of Helicobacter pylori gastritis, precancerous gastric lesion, and neoplasia

Premalignant gastric lesions such as atrophic gastritis and intestinal metaplasia frequently occur in subjects with long-term Helicobacter pylori (H. pylori) infection. The regular arrangement of collecting venules (RAC) is seen in the normal gastric corpus, whereas mucosal swelling and redness without RAC are observed in H. pylori-infected mucosa. Despite successful H. pylori eradication, the presence of atrophic gastritis and/or gastric intestinal metaplasia (GIM) is a risk factor for gastric cancer. With the development of advanced imaging technologies, recent studies have reported the usefulness of narrow-band imaging (NBI) for endoscopic diagnosis of atrophic gastritis and GIM. Using NBI endoscopy with magnification (M-NBI), atrophic gastritis is presented as irregular coiled microvessels and loss of gastric pits. Typical M-NBI endoscopic findings of GIM are a light blue crest and a white opaque substance. Based on the microvascular patterns, fine network, core vascular, and unclear patterns are useful for predicting gastric dysplasia in polypoid lesions. For diagnosis of early gastric cancer (EGC), a systematic classification using M-NBI endoscopy has been proposed on the basis of the presence of a demarcation line and an irregular microvascular/microsurface pattern. Furthermore, M-NBI endoscopy has been found to be more accurate for determining the horizontal margin of EGC compared to conventional endoscopy. In this review, we present up-to-date results on the clinical usefulness of gastroscopy with NBI for the diagnosis of H. pylori gastritis, precancerous gastric lesion, and neoplasia.

The Impact of Field of View on Understanding of a Movie Is Reduced by Magnifying Around the Center of Interest

Purpose

Magnification is commonly used to reduce the impact of impaired central vision. However, magnification limits the field of view (FoV) which may make it difficult to follow the story. Most people with normal vision look in about the same place at about the same time, the center of interest (COI), when watching “Hollywood” movies. We hypothesized that if the FoV was centered at the COI, then this view would provide more useful information than either the original image center or an unrelated view location (the COI locations from a different video clip) as the FoV reduced.

Methods

The FoV was varied between 100% (original) and 3%. To measure video comprehension as the FoV reduced, subjects described 30-second video clips in response to two open-ended questions. A computational, natural-language approach was used to provide an information acquisition (IA) score.

Results

The IA scores reduced as the FoV decreased. When the FoV was around the COI, subjects were better able to understand the content of the video clips (higher IA scores) as the FoV decreased than the other conditions. Thus, magnification around the COI may serve as a better video enhancement approach than simple magnification of the image center.

Conclusions

These results have implications for future image processing and scene viewing, which may help people with central vision loss view directed dynamic visual content (“Hollywood” movies).

Translational Relevance

Our results are promising for the use of magnification around the COI as a vision rehabilitation aid for people with central vision loss.

Polychlorinated biphenyls in a grassland food network: Concentrations, biomagnification, and transmission of toxicity

The production of polychlorinated biphenyls (PCBs) is prohibited by the Stockholm Convention in 2001, but the unintentionally produced PCBs are still continuously discharged into the environment. In this study, the distributions, biomagnification and toxicity amplification in a grassland food network (including inorganic environment, animals and vegetation) were investigated. PCB concentrations in various samples were determined, and PCBs appeared to be enriched as the trophic level increased. The PCB concentrations in the inorganic environment samples ranged from below the detection limit to 0.329 ng g^-1, and the PCB concentrations in vegetation were 0.0829-4.45 ng g^-1. The PCB concentration in snake subcutaneous fat (8.74 ng g^-1 lipid weight) was higher than the concentrations in other animal samples, and the next highest concentration was found in yellow weasel muscle (7.31 ng g^-1 lipid weight). Biomagnification factors were calculated for different PCBs and different organisms. Biomagnification was most obvious for organisms at the top of the food chain (the snake/mouse biomagnification ratio was >1000). The PCB-126 toxic equivalent concentration increased markedly as the trophic level increased. The toxic equivalent concentrations were 1200 times higher for high trophic level biota than low trophic level biota. PCB-169 had the highest toxic equivalent concentrations for the animal hair samples (0.00001 pg toxic equivalents g^-1). However, PCB-81 had the highest toxicity equivalent concentrations for the herdsmen hair samples. PCBs found at relatively low concentrations and low toxic equivalent concentrations at low trophic levels can be biomagnified as they are transferred through the food chain and can reach high actual and toxic equivalent concentrations at high trophic levels.

Dipping and rotating: two maneuvers to achieve maximum magnification during indirect transnasal laryngoscopy

Background

Since many years, office-based flexible transnasal laryngoscopy is a common routine procedure. The development of new technical equipment such as high-definition cameras and flexible tip-chip endoscopes nowadays allows for much more precise examination than a few years ago. In contrast to rigid laryngoscopy, it is possible to move the tip of the endoscope close to the vocal folds and to other structures of interest. Nevertheless, without professional handling of the equipment, one cannot benefit from the potential of the newest technology.

Method

Two easily performed and very helpful maneuvers in flexible endoscopy are described. The “dipping maneuver” enables a maximum magnification of the mucosal surfaces of the endolarynx as well as the examination of the subglottal region and the trachea by positioning the tip of the endoscope very close to the vocal folds or even in the upper trachea during long transnasal inspiration. During the “rotation laryngoscopy”, the tip of the endoscope is positioned in the posterior interarytenoid region by rotating the flexible endoscope by 180° and advancing it close to the glottis. This allows a close-up examination of the anterior commissure, the inferior aspect of the vocal folds and the inside of the Morgagni’s ventricle. Before performing transnasal flexible endoscopy, we routinely apply topical anesthesia sprayed intranasally.

Conclusion

The described techniques of flexible endoscopy are easily performed and allow a maximum magnification of the mucosal surfaces and otherwise not visible regions of the endolarynx.

Evaluating the efficacy of different magnification variables during root planing procedure under a surgical operating microscope in chronic periodontitis: A randomized clinical trial

Background:

The journey in the field of periodontics has destined from macrodentistry to microdentistry. The success of periodontal therapy always depends on better visual access and debridement which are prerequisites for achieving a clean and smooth root surface in attaining new attachment. Magnification is something which provides good hand-eye coordination resulting in better treatment outcomes. The aim of our study is to assess the effectiveness of magnification variable under a surgical operating microscope while performing root planing procedure.

Materials and Methods:

A randomized clinical trial was conducted on 45 patients who were diagnosed with mild-to-moderate chronic periodontitis and were treated under the surgical operating microscope with three different magnification variables (0.4, 0.6, and 1). Plaque index, gingival index (GI), and probing pocket depths (PPDs) were assessed from baseline to 4 weeks, whereas healing index was assessed after 2 weeks of root planing procedure.

Results:

The results of our study under the three magnification variables (0.4, 0.6 and 1) have shown no significant reduction in plaque or GI after 4 weeks of therapy. However, a significant reduction PPDs was observed after 4 weeks and improved healing index was observed after 2 weeks under all the three magnification variables with the variable 0.6 demonstrating more effective results.

Conclusion:

Even though all the three magnification variables have shown better treatment outcome and ergonomics, 0.6 magnification variable, i.e., ×3.5 – ×5, has demonstrated a more significant effect while performing root planing procedure.

Quantitative analysis of cake characteristics based on SEM imaging during coagulation-ultrafiltration process

Cake formed by flocs is a crucial factor to affect membrane fouling during coagulation-ultrafiltration process. To investigate the role of floc properties on cake, cake characteristics under various coagulant dosage conditions were calculated by scanning electron microscope (SEM) imaging. Results found that one SEM image with × 5000 magnification could accurately estimate cake porosity with relative error lower than 5.00% for all conditions, whereas more SEM images with × 10,000 magnification or × 20,000 magnification should be applied to calculate cake porosity precisely. This could be explained by different pore information of SEM images with various magnifications. Compared to single SEM image with × 10,000 magnification and × 20,000 magnification, single SEM image with × 5000 magnification contained the most comprehensive pore information and slightly overestimated pore area for pore smaller than 0.4 μm² due to lower resolution. To verify feasibility by SEM image evaluating cake characteristics, cake porosity calculated by SEM image and Carman-Kozeny equation were analyzed. The results showed that cake porosity estimated by these two methods were nearly the same, proving the feasibility of this method. Moreover, with the increase of coagulant dosage, cake porosity presented similar variation with floc average size, indicating that floc average size was likely to dominate cake porosity in this study. For pore characteristics, pore average characteristic length and pore average area were in accordance with floc fractal dimension, whereas pore fractal dimension and pore amount were consistent with floc average size. This gives specific information about the relation between floc properties and cake characteristics.

Combining high-throughput imaging flow cytometry and deep learning for efficient species and life-cycle stage identification of phytoplankton

BACKGROUND

Phytoplankton species identification and counting is a crucial step of water quality assessment. Especially drinking water reservoirs, bathing and ballast water need to be regularly monitored for harmful species. In times of multiple environmental threats like eutrophication, climate warming and introduction of invasive species more intensive monitoring would be helpful to develop adequate measures. However, traditional methods such as microscopic counting by experts or high throughput flow cytometry based on scattering and fluorescence signals are either too time-consuming or inaccurate for species identification tasks. The combination of high qualitative microscopy with high throughput and latest development in machine learning techniques can overcome this hurdle.

RESULTS

In this study, image based cytometry was used to collect ~ 47,000 images for brightfield and Chl a fluorescence at 60× magnification for nine common freshwater species of nano- and micro-phytoplankton. A deep neuronal network trained on these images was applied to identify the species and the corresponding life cycle stage during the batch cultivation. The results show the high potential of this approach, where species identity and their respective life cycle stage could be predicted with a high accuracy of 97%.

CONCLUSIONS

These findings could pave the way for reliable and fast phytoplankton species determination of indicator species as a crucial step in water quality assessment.

Use of Magnifying Loupes among Dental Professionals

AIM

The study aims to determine the perspective of dental professionals towards magnifying loupes and the selection criteria used while purchasing them.

MATERIALS AND METHODS

In this regard, a close-ended questionnaire was structured and distributed among 111 dental professionals. The questionnaire was designed to obtain information regarding the usage of magnifying loupes in dental practices and procedures, limiting factors, and selection criteria for purchasing. The results obtained from this study were statistically analyzed with the help of SPSS.

RESULTS

The findings illustrated that most respondents considered the use of magnifying loupes beneficial in dental practices. Also, 20.7% of them preferred "Through-the-Lens" magnifying loupes over "Flip-up" ones. Furthermore, many of the respondents considered that price, magnification, and resolution are the main factors in terms of selection criteria.

CONCLUSION

Although, there is an immense growth seen in the usage of magnifying loupes in dentistry; still there is a need to increase the awareness of the dental professionals regarding the positive outcomes of magnification aids in dentistry.

CLINICAL SIGNIFICANCE

The study will help enlightening clinicians regarding the selection criteria while purchasing magnifying loupes for dental practices.

Out of the loupe: The prevalence of coaxial misalignment of surgical loupes among dental professionals

BACKGROUND

Surgical loupes have been increasingly popular among dental professionals for their visual and postural benefits. However, dental professionals will receive the full benefit of surgical loupes only if the loupes are adjusted fully to fit the individual needs of each clinician. In this study, the authors examine coaxial alignment of surgical loupes, a critical criterion for the proper adjustment of these optical systems.

METHODS

The authors conducted an in-person survey by using a simple, quantitative visual tool to assess the coaxial alignment of surgical loupes among 97 dental professionals in British Columbia, Canada.

RESULTS

Findings indicated that 82% of dental professionals surveyed experienced coaxial misalignment with their surgical loupes. Dental professionals wearing front-lens-mounted (flip-up) surgical loupes with full vertical adjustability, front-lens-mounted surgical loupes with limited vertical adjustability, and through-the-lens surgical loupes were equally likely to be practicing with coaxial misalignment of their surgical loupes. Front-lens-mounted surgical loupes with full vertical adjustability were the only type of surgical loupe that can be adjusted to achieve full coaxial alignment reliably (P < .05).

CONCLUSIONS

There was a high prevalence of coaxial misalignment among dental professionals in this cohort. Not all surgical loupes on the market satisfy the criteria for optimal postural and visual support of clinicians.

PRACTICAL IMPLICATIONS

The visual tool developed in this study enabled dental professionals to identify coaxial misalignment effectively and efficiently. Findings from this study will assist dental professionals in making informed decisions when choosing their magnification equipment and prompt surgical loupe manufacturers to develop more evidence-based products.

Magnifying Blue Laser Imaging versus Magnifying Narrow-Band Imaging for the Diagnosis of Early Gastric Cancer: A Prospective, Multicenter, Comparative Study

BACKGROUND/AIMS

The diagnostic efficacy of magnifying blue laser imaging (M-BLI) and M-BLI in bright mode (M-BLI-bright) in the identification of early gastric cancer (EGC) was evaluated for comparison to that of magnifying narrow-band imaging (M-NBI).

METHODS

This prospective, multicenter study evaluated 114 gastric lesions examined using M-BLI, M-BLI-bright, and M-NBI between May 2012 and November 2012; 104 EGCs were evaluated by each modality. The vessel plus surface classification system was used to evaluate the demarcation line (DL), microvascular pattern (MVP), and microsurface pattern (MSP).

RESULTS

M-BLI, M-BLI-bright, and M-NBI revealed a DL for 96.1, 98.1, and 98.1% and irregular MVP for 95.1, 95.1, and 96.2% of lesions, respectively, with no significant difference. Irregular MSP was observed by M-BLI, M-BLI-bright, and M-NBI in 97.1, 90.4, and 78.8% of lesions, respectively, with significant differences (p < 0.001). The proportion of moderately differentiated adenocarcinoma with irregular MSP on M-BLI and absent MSP on M-NBI was significantly higher than that with irregular MSP on M-BLI and M-NBI (35.0 and 9.9%, respectively; p = 0.002).

CONCLUSION

M-BLI and M-BLI-bright provided excellent visualization of microstructures and microvessels similar to M-NBI. Irregular MSP in a moderately differentiated adenocarcinoma might be frequently visualized using M-BLI and M-BLI-bright compared with using M-NBI.

Comparative evaluation of manual scaling and root planing with or without magnification loupes using scanning electron microscope: A pilot study

Aim:

The aim of the present study is to compare the amount of remaining calculus, loss of tooth substance, and roughness of root surface after scaling and root planing with or without magnification loupes using scanning electron microscope.

Materials and Methods:

In the study, 30 teeth indicated for extractions due to severe chronic generalized periodontitis were included in the study. In test Group I, scaling and root planing was performed without magnification loupes, and in test Group II, scaling and root planing was performed with magnification loupes before extraction. In control Group III, no procedure was performed. After scaling and root planing, teeth were extracted followed by preparation of specimens. Specimens were then sent for scanning electron microscope study.

Results:

Statistically significant (P ≤ 0.05) differences were found among different test groups. Results showed that test Group II with magnification loupes had less remaining calculus and smoother surface with lesser amount of loss of cementum layer.

Conclusion:

From this, it was concluded that test Group II was more efficient in root debridement than test Group 1, so scaling and root planing done with magnification loupes will cause less damage to the tooth surface.

Radiation dose and magnification in pelvic X-ray: EOS™ imaging system versus plain radiographs

BACKGROUND

In plain pelvic X-ray, magnification makes measurement unreliable. The EOS™ (EOS Imaging, Paris France) imaging system is reputed to reproduce patient anatomy exactly, with a lower radiation dose. This, however, has not been assessed according to patient weight, although both magnification and irradiation are known to vary with weight. We therefore conducted a prospective comparative study, to compare: (1) image magnification and (2) radiation dose between the EOS imaging system and plain X-ray.

HYPOTHESIS

The EOS imaging system reproduces patient anatomy exactly, regardless of weight, unlike plain X-ray.

MATERIAL AND METHOD

A single-center comparative study of plain pelvic X-ray and 2D EOS radiography was performed in 183 patients: 186 arthroplasties; 104 male, 81 female; mean age 61.3±13.7years (range, 24-87years). Magnification and radiation dose (dose-area product [DAP]) were compared between the two systems in 186 hips in patients with a mean body-mass index (BMI) of 27.1±5.3kg/m² (range, 17.6-42.3kg/m²), including 7 with morbid obesity.

RESULTS

Mean magnification was zero using the EOS system, regardless of patient weight, compared to 1.15±0.05 (range, 1-1.32) on plain X-ray (P<10^-5). In patients with BMI<25, mean magnification on plain X-ray was 1.15±0.05 (range, 1-1.25) and, in patients with morbid obesity, 1.22±0.06 (range, 1.18-1.32). The mean radiation dose was 8.19±2.63dGy/cm² (range, 1.77-14.24) with the EOS system, versus 19.38±12.37dGy/cm² (range, 4.77-81.75) with plain X-ray (P<10^-4). For BMI >40, mean radiation dose was 9.36±2.57dGy/cm² (range, 7.4-14.2) with the EOS system, versus 44.76±22.21 (range, 25.2-81.7) with plain X-ray. Radiation dose increased by 0.20dGy with each extra BMI point for the EOS system, versus 0.74dGy for plain X-ray.

CONCLUSION

Magnification did not vary with patient weight using the EOS system, unlike plain X-ray, and radiation dose was 2.5-fold lower.

LEVEL OF EVIDENCE

3, prospective case-control study.

Gray matter alteration associated with pain catastrophizing in patients 6 months after lumbar disk surgery: a voxel-based morphometry study

Supplemental Digital Content is Available in the Text.

The link between pain catastrophizing and the differential effect of the components magnification and helplessness on brain morphology in patients with low back pain

Introduction:

Pain catastrophizing (PC), the increased attention to harmful aspects of pain (magnification), and the belief of low controllability (helplessness) has been shown to be important in the maintenance of pain. A growing research on structural alterations in chronic pain revealed an association between PC and brain areas that are involved in affective and cognitive pain processing. However, little is known about a differential effect of the components magnification and helplessness.

Objective:

The aim of this study was to identify brain regions associated with overall PC and with the single components of magnification and helplessness.

Methods:

We investigated 29 patients 6 months after lumbar disk surgery using voxel-based morphometry. Magnification and helplessness were assessed with subscales of the Avoidance-Endurance Questionnaire (AEQ); overall PC was computed using the sum score. The structural brain imaging data were preprocessed and analyzed using SPM8 and VBM8. Multiple regression analyses were performed with PC scales as predictors and depression as covariate.

Results:

Pain catastrophizing was significantly associated with cortical gray matter in brain areas involved in processing attentional, sensory, and affective aspects of pain, including the left posterior cingulate cortex, supplementary motor area, and medial frontal gyrus. In addition, we provide preliminary evidence for brain structure association related to magnification and helplessness.

Conclusion:

This study provides evidence for PC-related structural alterations in patients with low back pain, which are consistent with findings from previous research in different chronic pain disorders. This study is the first to evaluate brain changes related to differential domains of PC.

Modern Endodontic Microsurgery Concepts: A Clinical Update

Increased use of the surgical operating microscope in endodontic surgery has elucidated many shortcomings of previous techniques and along with microsurgical instruments and new more biologically acceptable root-end filling materials has started the new microsurgical era in surgical endodontics. Endodontic microsurgery is a minimally invasive technique that results in less postoperative pain and edema and faster wound healing. It offers a significantly higher success rate than traditional apical surgery technique. The components, key concepts and procedural steps of endodontic microsurgery as well as the prognosis and predictability of modern root-end procedures are presented in this review.

Scanning Electron Microscopy Sample Preparation and Imaging

Scanning electron microscopes allow us to reach magnifications of 20-130,000× and resolve compositional and topographical images with intense detail. These images are created by bombarding a sample with electrons in a focused manner to generate a black and white image from the electrons that bounce off of the sample. The electrons are detected using positively charged detectors. Scanning electron microscopy permits three-dimensional imaging of desiccated specimens or wet cells and tissues by using variable pressure chambers. SEM ultrastructural analysis and intracellular imaging supplement light microscopy for molecular profiling of prokaryotes, plants, and mammals. This chapter demonstrates how to prepare and image samples that are (a) desiccated and conductive, (b) desiccated and nonconductive but coated with an electron conductive film using a gold sputter coater, and

Application of a Compact High-Definition Exoscope for Illumination and Magnification in High-Precision Surgical Procedures

BACKGROUND

The basic necessities for surgical procedures are illumination, exposure, and magnification. These have undergone transformation in par with technology. One of the recent developments is the compact magnifying exoscope system. In this report, we describe the application of this system for surgical operations and discuss its advantages and pitfalls.

METHODS

We used the ViTOM exoscope mounted on the mechanical holding arm. The following surgical procedures were conducted: lumbar and cervical spinal canal decompression (n = 5); laminotomy and removal of lumbar migrated disk herniations (n = 4); anterior cervical diskectomy and fusion (n = 1); removal of intraneural schwannomas (n = 2); removal of an acute cerebellar hemorrhage (n = 1); removal of a parafalcine atypical cerebral hematoma caused by a dural arteriovenous fistula (n = 1); and microsutures and anastomoses of a nerve (n = 1), an artery (n = 1), and veins (n = 2).

RESULTS

The exoscope offered excellent, magnified, and brilliantly illuminated high-definition images of the surgical field. All surgical operations were successfully completed. The main disadvantage was the adjustment and refocusing using the mechanical holding arm. The time required for the surgical operation under the exoscope was slightly longer than the times required for a similar procedure performed using an operating microscope.

CONCLUSIONS

The magnifying exoscope is an effective and nonbulky tool for surgical procedures. In visualization around the corners, the exoscope has better potential than a microscope. With technical and technologic modifications, the exoscope might become the next generation in illumination, visualization, exposure, and magnification for high-precision surgical procedures.

Awareness and attitude toward using dental magnification among dental students and residents at King Abdulaziz University, Faculty of Dentistry

Background

The authors conducted a study aimed to assess the awareness and attitude among dental students and residents at King Abdulaziz University, Faculty of Dentistry (KAUFD) toward using dental magnification.

Methods

An e-questionnaire was formulated then sent to dental students and residents (n = 651). The questionnaire included questions that assessed both the awareness and attitude toward using dental magnification. Data were analyzed using IBM SPSS version 22. The chi-square test was used to establish relationships between categorical variables.

Results

The response rate was 69.7 % (n = 454). Of those, 78.1 % did not use magnification during dental procedures. However, 81.8 % agreed that dental magnification could enhance the accuracy and quality of their dental work. Thus, 91.6 % thought it would be useful in endodontics and 46.3 % voted for surgery. Of the 21.9 % that used magnification, dental loupes were mostly used, 55.9 %. The majority (59.4 %) of the participants believed that using dental magnification should be introduced by faculty beginning in Year I of dental school.

Conclusions

Among our respondents, most of the undergraduate students did not use dental magnification nor attended courses in the use of dental magnifications. However, most of the students were aware of its significance in improving the accuracy and quality of their work.

Video Telescope Operating Microscopy

Exotic pet veterinarians frequently have to operate on small animals, and magnification is commonly used. Existing endoscopy equipment can be used with a mechanical arm and telescope to enable video telescope operating microscopy. The additional equipment items and their specifics are described, and several case examples are provided.

Polyp detection rates using magnification with narrow band imaging and white light

AIM: To compare the yield of adenomas between narrow band imaging and white light when using high definition/magnification.

METHODS: This prospective, non-randomized comparative study was performed at the endoscopy unit of veteran affairs medical center in Phoenix, Arizona. Consecutive patients undergoing first average risk colorectal cancer screening colonoscopy were selected. Two experienced gastroenterologists performed all the procedures that were blinded to each other’s findings. Demographic details were recorded. Data are presented as mean ± SEM. Proportional data were compared using the χ² test and means were compared using the Student’s t test. Tandem colonoscopy was performed in a sequential and segmental fashion using one of 3 strategies: white light followed by narrow band imaging [Group A: white light (WL) → narrow band imaging (NBI)]; narrow band imaging followed by white light (Group B: NBI → WL) and, white light followed by white light (Group C: WL → WL). Detection rate of missed polyps and adenomas were evaluated in all three groups.

RESULTS: Three hundred patients were studied (100 in each Group). Although the total time for the colonoscopy was similar in the 3 groups (23.8 ± 0.7, 22.2 ± 0.5 and 24.1 ± 0.7 min for Groups A, B and C, respectively), it reached statistical significance between Groups B and C (P < 0.05). The cecal intubation time in Groups B and C was longer than for Group A (6.5 ± 0.4 min and 6.5 ± 0.4 min vs 4.9 ± 0.3 min; P < 0.05). The withdrawal time for Groups A and C was longer than Group B (18.9 ± 0.7 min and 17.6 ± 0.6 min vs 15.7 ± 0.4 min; P < 0.05). Overall miss rate for polyps and adenomas detected in three groups during the second look was 18% and 17%, respectively (P = NS). Detection rate for polyps and adenomas after first look with white light was similar irrespective of the light used during the second look (WL → WL: 13.7% for polyps, 12.6% for adenomas; WL → NBI: 14.2% for polyps, 11.3% for adenomas). Miss rate of polyps and adenomas however was significantly higher when NBI was used first (29.3% and 30.3%, respectively; P < 0.05). Most missed adenomas were ≤ 5 mm in size. There was only one advanced neoplasia (defined by size only) missed during the first look.

CONCLUSION: Our data suggest that the tandem nature of the procedure rather than the optical techniques was associated with the detection of additional polyps’ and adenomas.

Magnification effects on distance estimation during robotic suturing

We aimed to understand the impact of magnification on distance estimation during robotic suturing. Twenty subjects estimated the lengths of various sutures externally, in plain sight, to validate their ability to measure distances. They then robotically repaired a 3-cm cystotomy, suturing 10 mm above and below the incision and 10 mm on either side of the incision. The bladder was removed and distances measured. A total of 20 surgeons were analyzed: 7 residents, 8 fellows, and 5 staff. Specialties comprised four urologists, eight general gynecologists, two urogynecologists, three gynecologic oncologists, and three reproductive endocrinologists. The mean estimation for external suture length was not significant at 10 mm: mean = 9.6 (±3.2) mm (p = 0.59). When comparing these data sets, the externally visualized 10-mm suture versus the suture-to-suture and the suture-to-incision distances were both significantly different (p = 0.002 and p < 0.001, respectively). The mean distance between each suture was 6.5 (±1.8) mm, which was significantly different from the 10-mm goal (p < 0.001, 95 % confidence interval (CI) [-4.4,-2.6]). The mean distance from the suture to the incision was 4.1 (±1.0) mm, which was also statistically significantly different from the goal (p < 0.001, 95 % CI [-6.3,-5.4]). Surgical experience was negatively associated with suture-to-incision distance (r s = -0.53, p = 0.016). Inter-suture distance was also negatively associated with experience (r s = -0.30, p = 0.22), though not statistically significant. In vivo distances are significantly underestimated during robotic suture placement. Interestingly, the most experienced surgeons had the worst distance estimation from the incision to the suture.

Persistent and automatic intraoperative 3D digitization of surfaces under dynamic magnifications of an operating microscope

One of the major challenges impeding advancement in image-guided surgical (IGS) systems is the soft-tissue deformation during surgical procedures. These deformations reduce the utility of the patient's preoperative images and may produce inaccuracies in the application of preoperative surgical plans. Solutions to compensate for the tissue deformations include the acquisition of intraoperative tomographic images of the whole organ for direct displacement measurement and techniques that combines intraoperative organ surface measurements with computational biomechanical models to predict subsurface displacements. The later solution has the advantage of being less expensive and amenable to surgical workflow. Several modalities such as textured laser scanners, conoscopic holography, and stereo-pair cameras have been proposed for the intraoperative 3D estimation of organ surfaces to drive patient-specific biomechanical models for the intraoperative update of preoperative images. Though each modality has its respective advantages and disadvantages, stereo-pair camera approaches used within a standard operating microscope is the focus of this article. A new method that permits the automatic and near real-time estimation of 3D surfaces (at 1 Hz) under varying magnifications of the operating microscope is proposed. This method has been evaluated on a CAD phantom object and on full-length neurosurgery video sequences (∼1 h) acquired intraoperatively by the proposed stereovision system. To the best of our knowledge, this type of validation study on full-length brain tumor surgery videos has not been done before. The method for estimating the unknown magnification factor of the operating microscope achieves accuracy within 0.02 of the theoretical value on a CAD phantom and within 0.06 on 4 clinical videos of the entire brain tumor surgery. When compared to a laser range scanner, the proposed method for reconstructing 3D surfaces intraoperatively achieves root mean square errors (surface-to-surface distance) in the 0.28-0.81 mm range on the phantom object and in the 0.54-1.35 mm range on 4 clinical cases. The digitization accuracy of the presented stereovision methods indicate that the operating microscope can be used to deliver the persistent intraoperative input required by computational biomechanical models to update the patient's preoperative images and facilitate active surgical guidance.

Postural Assessment of Students Evaluating the Need of Ergonomic Seat and Magnification in Dentistry

Dental students using conventional chairs need immediate change in their posture. Implementing an ergonomic posture is necessary as they are at high risk for developing musculoskeletal disorders. This study recommends the use of an ergonomic seat and magnification system to enhance the visibility and the posture of an operator. The aim of this study is to make a foray into the hazards caused by inappropriate posture of dental students while working. It also aims at creating a cognizance about the related health implications among the dental fraternity at large, and to understand the significance of adopting an ergonomic posture since the beginning of the professional course. In the present study, postures have been assessed by using rapid upper limb assessment (RULA). This method uses diagrams of body postures and three scoring tables to evaluate ones exposure to risk factors. Ninety students from II BDS (preclinical students in the second year of dental school) were assessed in three groups using three different seats with and without magnification system. The results recorded significantly higher RULA scores for the conventional seats without using the magnification system compared to the SSC (Salli Saddle Chair-an ergonomic seat) with the use of magnification system. A poor ergonomic posture can make the dental students get habituated to the wrong working style which might lead to MSDs (Musculoskeletal diseases). It is advisable to acclimatize to good habits at the inception of the course, to prevent MSDs later in life.

Periodontal microsurgery: A case report

The purpose of this article is to limelight the benefit of periodontal microsurgery in the surgical disciplines. It reviews the benefits and potential applications of magnification and microsurgery in the specialty of periodontics and a case report on microsurgical approach for free gingival graft surgery in the treatment of gingival recession. The increased demand for mucogingival esthetics has required the optimization of periodontal procedures. Microsurgery is a minimally invasive technique that is performed with the surgical microscope and adapted instruments and suture materials. Although this hardware and knowledge of various operations are necessary to achieve patient esthetic expectations, clinicians must be willing to undergo an extended period of systematic training to become familiar with novel operating procedures and instruments. This article describes the application of the surgical microscope to provide enhanced perioplastic treatment.

Characterization of polyethylene wear particle: The impact of methodology

Due to the prevalence of problems caused by wear particles, the reduced durability of total joint replacements is well documented. The characterization of wear debris enables the size and morphology of these wear particles to be measured and provides an assessment of the biological response in vivo. However, the impact of different methodologies of particle analysis is not yet clear. Hence, the aim of this investigation was to analyze the influence of different particle characterization methods performed by three research centers within the scope of a "round robin test". To obtain knowledge about possible pitfalls, single steps of the particle characterization process (storage, pore size of the filter, coating durations by gold sputtering and scanning electron microscopy (SEM) magnification) were analyzed. The round robin test showed significant differences between the research groups, especially for the morphology of the particles. The SEM magnification was identified as having the greatest influence on the size and shape of the particles, followed by the storage conditions of the wear particle containing lubricant. Gold sputter coating and filter pore size also exhibit significant effects. However, even though they are statistically significant, it should be emphasized that the differences are small. In conclusion, particle characterization is a complex analytical method with a multiplicity of influencing factors. It becomes apparent that a comparison of wear particle results between different research groups is challenging.

Narrow-band imaging with magnifying endoscopy is accurate for detecting gastric intestinal metaplasia

AIM

To investigate the predictive value of narrow-band imaging with magnifying endoscopy (NBI-ME) for identifying gastric intestinal metaplasia (GIM) in unselected patients.

METHODS

We prospectively evaluated consecutive patients undergoing upper endoscopy for various indications, such as epigastric discomfort/pain, anaemia, gastro-oesophageal reflux disease, suspicion of peptic ulcer disease, or chronic liver diseases. Patients underwent NBI-ME, which was performed by three blinded, experienced endoscopists. In addition, five biopsies (2 antrum, 1 angulus, and 2 corpus) were taken and examined by two pathologists unaware of the endoscopic findings to determine the presence or absence of GIM. The correlation between light blue crest (LBC) appearance and histology was measured. Moreover, we quantified the degree of LBC appearance as less than 20% (+), 20%-80% (++) and more than 80% (+++) of an image field, and the semiquantitative evaluation of LBC appearance was correlated with IM percentage from the histological findings.

RESULTS

We enrolled 100 (58 F/42 M) patients who were mainly referred for gastro-esophageal reflux disease/dyspepsia (46%), cancer screening/anaemia (34%), chronic liver disease (9%), and suspected celiac disease (6%); the remaining patients were referred for other indications. The prevalence of Helicobacter pylori (H. pylori) infection detected from the biopsies was 31%, while 67% of the patients used proton pump inhibitors. LBCs were found in the antrum of 33 patients (33%); 20 of the cases were classified as LBC+, 9 as LBC++, and 4 as LBC+++. LBCs were found in the gastric body of 6 patients (6%), with 5 of them also having LBCs in the antrum. The correlation between the appearance of LBCs and histological GIM was good, with a sensitivity of 80% (95%CI: 67-92), a specificity of 96% (95%CI: 93-99), a positive predictive value of 84% (95%CI: 73-96), a negative predictive value of 95% (95%CI: 92-98), and an accuracy of 93% (95%CI: 90-97). The NBI-ME examination overlooked GIM in 8 cases, but the GIM was less than 5% in 7 of the cases. Moreover, in the 6 false positive cases, the histological examination showed the presence of reactive gastropathy (4 cases) or H. pylori active chronic gastritis (2 cases). The semiquantitative correlation between the rate of LBC appearance and the percentage of GIM was 79% (P < 0.01).

CONCLUSION

NBI-ME achieved good sensitivity and specificity in recognising GIM in an unselected population. In routine clinical practice, this technique can reliably target gastric biopsies.

Web-based system for training and dissemination of a magnification chromoendoscopy classification

AIM: To evaluate the use of web-based technologies to assess the learning curve and reassess reproducibility of a simplified version of a classification for gastric magnification chromoendoscopy (MC).

METHODS: As part of a multicenter trial, a hybrid approach was taken using a CD-ROM, with 20 films of MC lasting 5 s each and an “autorun” file triggering a local HTML frameset referenced to a remote questionnaire through an Internet connection. Three endoscopists were asked to prospectively and independently classify 10 of these films randomly selected with at least 3 d apart. The answers were centrally stored and returned to participants together with adequate feedback with the right answer.

RESULTS: For classification in 3 groups, both intra- [Cohen’s kappa (κ) = 0.79-1.00 to 0.89-1.00] and inter-observer agreement increased from 1st (moderate) to 6th observation (κ = 0.94). Also, agreement with reference increased in the last observations (0.90, 1.00 and 1.00, for observers A, B and C, respectively). Validity of 100% was obtained by all observers at their 4th observation. When a 4th (sub)group was considered, inter-observer agreement was almost perfect (κ = 0.92) at 6th observation. The relation with reference clearly improved into κ (0.93-1.00) and sensitivity (75%-100%) at their 6th observations.

CONCLUSION: This MC classification seems to be easily explainable and learnable as shown by excellent intra- and inter-observer agreement, and improved agreement with reference. A web system such as the one used in this study may be useful for endoscopic or other image based diagnostic procedures with respect to definition, education and dissemination.

Clinical significance of type VI pit pattern subclassification in determining the depth of invasion of colorectal neoplasms

AIM: To clarify whether subclassification of the type V_I pit pattern on the basis of magnifying colonoscopy findings is useful in determining the type and depth of invasion of colorectal neoplasms.

METHODS: We retrospectively analyzed 272 colorectal neoplasms (117 dysplasias and 155 submucosal invasive carcinomas; 228 patients) with a type V pit pattern [type V_I, n = 202; type V_N, n = 70 (Kudo and Tsuruta classification system)]. We divided lesions with a type V_I pit pattern into two subclasses, mildly irregular lesions and severely irregular lesions, according to the prominent and detailed magnifying colonoscopy findings. We examined the relation between these two subclasses and histology/invasion depth.

RESULTS: One hundred and four lesions (51.5%) were judged to be mildly irregular, and 98 lesions (48.5%) were judged to be severely irregular. Ninety-seven (93.3%) mildly irregular lesions showed dysplasias or submucosal invasion of less than 1000 &mgr;m (SM < 1000 &mgr;m). Fifty-five (56.1%) severely irregular lesions showed submucosal invasion equal to or deeper than 1000 &mgr;m (SM ≥ 1000 &mgr;m). Mild irregularity was found significantly more often in dysplasias or lesions with SM < 1000 &mgr;m than in lesions with SM ≥ 1000 &mgr;m (P < 0.01).

CONCLUSION: Subclassification of the type V_I pit pattern is useful for identifying dysplasias or lesions with SM < 1000 &mgr;m.