Radiopacity evaluation of root-end filling materials by digitization of images

The purpose of this study was to evaluate the radiopacity of 5 root-end filling materials (white MTA-Angelus, grey MTA-Angelus, IRM, Super EBA and Sealer 26). Five specimens (10 mm diameter X 1 mm thickness) were made from each material and radiographed next to an aluminum stepwedge varying in thickness from 2 to 16 mm. Radiographs were digitized and the radiopacity of the materials was compared to that of the aluminum stepwedge using VIXWIN 2000 software in millimeters of aluminum ( mm Al). Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. Radiopacity values varied from 3 mm Al to 5.9 mm Al. Sealer 26 and IRM presented the highest radiopacity values (p<0.05), while white/grey MTA and Super EBA presented the lowest radiopacity values (p<0.05). The tested root- end filling materials presented different radiopacities, white/grey MTA and Super EBA being the least radiopaque materials.

Comparative study of MTA and other materials in retrofilling of pulpless dogs' teeth

This in vivo study compared the effect of mineral trioxide aggregate (MTA), IRM, Super EBA and ZOE in a puttylike consistency, used as retrofilling materials, in the healing process of periapical tissue of pulpless dogs' teeth submitted to a conventional retrofilling technique. Twenty-four premolars obtained from three dogs were used. At the first intervention, the animals were anesthetized, coronal access was obtained and pulpectomy was done. Root canals were kept open to the oral environment for 180 days to induce the formation of apical lesions. After surgical removal of the lesions with curettes, 2 mm of the apical root was cut out perpendicular to the long axis of the teeth, and root-end cavities were shaped with a low-speed round bur. The bone cavities were irrigated and dried, and the root-end cavities were filled with MTA, IRM, Super EBA and ZOE in a puttylike consistency. The bone cavities were passively filled with blood and flaps were sutured. The coronal access openings were cleaned and double-sealed with ZOE and amalgam. After 180 days, the animals were killed by anesthetic overdose, maxilla and mandible were removed and the pieces were processed for histomorphologic analysis. Data were evaluated blindly on the basis of several histopathologic events and the scores obtained were analyzed statistically using the Kruskal Wallis test. No significant differences were observed among MTA, Super EBA and IRM (p>0.05). However, ZOE had a significantly more negative influence on the apical healing (p<0.05). In conclusion, MTA, Super EBA and IRM had similar histopathologic effects among each other and better performance than ZOE used in a puttylike consistency. Furthermore, only MTA stimulated hard tissue deposition in direct contact with the retrofilling material, even when it was inserted under critical conditions.

SEM Evaluation of the Interface Between Filling and Root- End Filling Materials

The aim of this ex vivo study was to evaluate, by scanning electron microscopy (SEM), the presence of gaps at the interface between filling material and three root-end filling materials. Thirty human upper molars disto-buccal roots were instrumented and filled with gutta-percha and eugenol-based sealer. The apicoectomy was performed 2mm from the apex and retrograde cavities were prepared with ultrasonic points (3mm in deep). The samples were divided into three experimental groups (n=10): Group Iwhite mineral trioxide aggregate (MTA); Group IISuper EBA; and Group IIIPortland cement. The root-end filling materials were inserted into the retocavities using a MTA carrier. After 48h, the roots were transversally sectioned in order to obtain the apical 5mm. Next, each specimen was prepared longitudinally with crescent granulation of abrasives water-wet sandpapers in order to expose the filling and root-end filling materials. Then, the specimens were subjected to slow dehydration with silica gel, mounted onto specific stubs and coated with paladium coverage for SEM analysis of the interface between filling and root-end filling materials. The percentage of gaps at the interfacial area was calculated by using Image Tool 3.0 software. Super EBA presented the higher percentage of gaps (1.5 +/- 0.67%), whereas MTA presented the lowest values (0.33 +/- 0.20%; p=0.0004). Despite the statistical differences observed between Super EBA and MTA, all the root-end filling materials presented great adaptation to the filling material, presenting small amount of gaps. SCANNING 36:252-257, 2014. (c) 2013 Wiley Periodicals, Inc.

Periapical Tissue Response After Use of Intermediate Restorative Material, Gutta-Percha, Reinforced Zinc Oxide Cement, and Mineral Trioxide Aggregate as Retrograde Root-End Filling Materials: A Histologic Study in Dogs

Purpose: To investigate the periapical tissue response of 4 different retrograde root-filling materials, ie, intermediate restorative material, thermoplasticized gutta-percha, reinforced zinc oxide cement (Super-EBA), and mineral trioxide aggregate (MTA), in conjunction with an ultrasonic root-end preparation technique in an animal model. Materials and Methods: Vital roots of the third and fourth right mandibular premolars in 6 healthy mongrel dogs were apicectomized and sealed with 1 of the materials using a standardized surgical procedure. After 120 days, the animals were sacrificed and the specimens were analyzed radiologically, histologically, and scanning electron microscopically. The Fisher exact test was performed on the 2 outcome values. Results: Twenty-three sections were analyzed histologically. Evaluation showed better re-establishment of the periapical tissues and generally lower inflammatory infiltration in the sections from teeth treated with the intermediate restorative material and the MTA. New root cement on the resected dentin surfaces was seen on all sections regardless of the used material. New hard tissue formation, directly on the surface of the material, was seen only in the MTA sections. There was no statistical difference in outcome among the tested materials. Conclusions: The results from this dog model favor the intermediate restorative material and MTA as retrograde fillings when evaluating the bone defect regeneration. MTA has the most favorable periapical tissue response when comparing the biocompatibility of the materials tested. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:2041-2047, 2012

Back-scattered electron imaging for leakage analysis of four retrofilling materials

This study aimed to evaluate, ex vivo, the nanoleakage in dentinal tubules, the linear infiltration of silver nitrate in the dentin wall/root-end filling material interface, and the presence of gaps in this interface in root-end cavities filled with 4 filling materials. Forty-eight disto-buccal root canals of maxillary molars were instrumented and filled. Retrograde cavities were prepared with ultrasonic points (apical 2 mm). The samples were divided into 2 control groups (n = 4) and 4 experimental groups (n = 10): Group I white mineral trioxide aggregate (MTA); Group II Super EBA; Group III Portland cement; and Group IV Sealer 26. After 1 week, the specimens were subjected to silver nitrate and prepared for SEM (backscattered electrons). In the apical-apical segment, an area with significantly higher leakage was observed for Super EBA, followed by Portland cement, MTA, and Sealer 26 (P = 0.0054). In the medium and cervical segments, all materials showed the same leakage behavior (P = 0.1815 and P = 0.1723, respectively). The linear infiltration at the dentin wall/root-end filling material interface was higher with Super EBA than the other groups. No differences in the percentage of gaps along the 3 mm of dentin wall/root-end filling material interface between the 4 materials were evident (P > 0.05). Nanoleakage occurred mainly in the apical segment of the samples, and Super EBA showed the highest values. The area and linear leakage were lower in the middle and coronal segments, regardless of the root-end filling material. No material perfectly sealed the root-end cavities, which allowed for the leakage occurrence. Microsc. Res. Tech. 75:796800, 2012. (C) 2011 Wiley Periodicals, Inc.

Service quality in Hong Kong : wet markets vs super markets

Purpose – The purpose of this paper is to determine consumer perceptions of service quality in wet markets and supermarkets in Hong Kong. Design/methodology/approach – A questionnaire was developed and distributed via a convenience sample to consumers in shopping malls in Causeway Bay, Mong Kok and Tsuen Wan. Findings – The study finds that supermarkets outperformed wet markets across all aspects of service quality as measured by SERVQUAL-P. Research limitations/implications – Implications suggest that wet market vendors are not providing the level of service quality demanded by their customers. In particular, findings suggest that wet market vendors need to improve the visual attractiveness of their stalls, work on making them look more professional and start using more modern equipment. Practical implications – Wet market vendors in conjunction with government representatives need to develop standards of service quality for wet markets across Hong Kong. This is imperative if the wet market model is to survive in what is a highly competitive food retailing industry. Without action, it appears that the supermarketization of the Hong Kong food retailing industry will continue unabated. Originality/value – This paper adds to a small but growing research stream examining service quality in the food retailing industry in Hong Kong. It provides empirical results that guide suggested actions for change.

Automatic tracking, super-resolution and recognition of human faces from surveillance video

Identifying an individual from surveillance video is a difficult, time consuming and labour intensive process. The proposed system aims to streamline this process by filtering out unwanted scenes and enhancing an individual's face through super-resolution. An automatic face recognition system is then used to identify the subject or present the human operator with likely matches from a database. A person tracker is used to speed up the subject detection and super-resolution process by tracking moving subjects and cropping a region of interest around the subject's face to reduce the number and size of the image frames to be super-resolved respectively. In this paper, experiments have been conducted to demonstrate how the optical flow super-resolution method used improves surveillance imagery for visual inspection as well as automatic face recognition on an Eigenface and Elastic Bunch Graph Matching system. The optical flow based method has also been benchmarked against the ``hallucination'' algorithm, interpolation methods and the original low-resolution images. Results show that both super-resolution algorithms improved recognition rates significantly. Although the hallucination method resulted in slightly higher recognition rates, the optical flow method produced less artifacts and more visually correct images suitable for human consumption.

Nation and Internet : Malaysia and the multimedia super corridor

As part of a development plan-in-progress spanning a total of 25 years (1996 to 2020), Malaysia’s Multimedia Super Corridor MSC provides a unique opportunity to witness a brief and microcosmic unfolding of that process which Lewis Mumford lays out in exhaustive detail in Technics and Civilization (Mumford, 1963). What makes it doubly interesting is the interlocking of national imagining, destiny and progress with a specific group of technologies, information and communication technologies (ICT), of which the Internet is part. This paper casts Malaysia’s development and implementation of the MSC as the core round which an enquiry of the association between the nation and the Internet is woven. I argue here that there are 3 dissonances that occur within the relationship between the Malaysian nation and the Internet. The first of these arises from the tension between the premises underlying techno-utopianism and pro-Malay affirmative action. The second is born of the discordance between the “guaranteed” freedom from online censorship and the absolute punitive powers of the state. The third lies in the contradiction between the Malaysian nation, as practiced through graduated sovereignty and its pro-Bumiputera affirmative action. Together, these three comprise the inflections that the Internet has on Malaysia. Further, I contend that aside from adding to the number of ways in which the nation is understood and experienced, these inflections also have the potential to disrupt how the nation is lived. By lived I mean to denote the realisation of the nation that occurs in and through everyday life.

Focus-score weighted super-resolution for uncooperative iris recognition at a distance and on the move

Uncooperative iris identification systems at a distance and on the move often suffer from poor resolution and poor focus of the captured iris images. The lack of pixel resolution and well-focused images significantly degrades the iris recognition performance. This paper proposes a new approach to incorporate the focus score into a reconstruction-based super-resolution process to generate a high resolution iris image from a low resolution and focus inconsistent video sequence of an eye. A reconstruction-based technique, which can incorporate middle and high frequency components from multiple low resolution frames into one desired super-resolved frame without introducing false high frequency components, is used. A new focus assessment approach is proposed for uncooperative iris at a distance and on the move to improve performance for variations in lighting, size and occlusion. A novel fusion scheme is then proposed to incorporate the proposed focus score into the super-resolution process. The experiments conducted on the The Multiple Biometric Grand Challenge portal database shows that our proposed approach achieves an EER of 2.1%, outperforming the existing state-of-the-art averaging signal-level fusion approach by 19.2% and the robust mean super-resolution approach by 8.7%.

Orchestrating knowledge-based urban development : lessons from multimedia super corridor, Malaysia

In the era of knowledge economy, cities and regions have started increasingly investing on their physical, social and knowledge infrastructures so as to foster, attract and retain global talent and investment. Knowledge-based urban development as a new paradigm in urban planning and development is being implemented across the globe in order to increase the competitiveness of cities and regions. This chapter provides an overview of the lessons from Multimedia Super Corridor, Malaysia as one of the first large scale manifestations of knowledge-based urban development in South East Asia. The chapter investigates the application of the knowledge-based urban development concept within the Malaysian context, and, particularly, scrutinises the development and evolution of Multimedia Super Corridor by focusing on strategies, implementation policies, infrastructural implications, and agencies involved in the development and management of the corridor. In the light of the literature and case findings, the chapter provides generic recommendations, on the orchestration of knowledge-based urban development, for other cities and regions seeking such development.

Developing a knowledge-based urban development analysis framework : the case of multimedia super corridor, Malaysia

Purpose: In the global knowledge economy, investment in knowledge-intensive industries and information and communication technology (ICT) infrastructures are seen as significant factors in improving the overall socio-economic fabric of cities. Consequently knowledge-based urban development (KBUD) has become a new paradigm in urban planning and development, for increasing the welfare and competitiveness of cities and regions. The paper discusses the critical connections between KBUD strategies and knowledge-intensive industries and ICT infrastructures. In particular, it investigates the application of the knowledge-based urban development concept by discussing one of South East Asia’s large scale manifestations of KBUD; Malaysia’s Multimedia Super Corridor. ----- ----- Design/methodology/approach: The paper provides a review of the KBUD concept and develops a knowledge-based urban development assessment framework to provide a clearer understanding of development and evolution of KBUD manifestations. Subsequently the paper investigates the implementation of the KBUD concept within the Malaysian context, and particularly the Multimedia Super Corridor (MSC). ----- ----- Originality/value: The paper, with its KBUD assessment framework, scrutinises Malaysia’s experince; providing an overview of the MSC project and discussion of the case findings. The development and evolution of the MSC is viewed with regard to KBUD policy implementation, infrastructural implications, and the agencies involved in the development and management of the MSC. ----- ----- Practical implications: The emergence of the knowledge economy, together with the issues of globalisation and rapid urbanisation, have created an urgent need for urban planners to explore new ways of strategising planning and development that encompasses the needs and requirements of the knowledge economy and society. In light of the literature and MSC case findings, the paper provides generic recommendations, on the orchestration of knowledge-based urban development, for other cities and regions seeking to transform to the knowledge economy.

Robust mean super-resolution for less cooperative NIR iris recognition at a distance and on the move

Less cooperative iris identification systems at a distance and on the move often suffers from poor resolution. The lack of pixel resolution significantly degrades the iris recognition performance. Super-resolution has been considered to enhance resolution of iris images. This paper proposes a pixelwise super-resolution technique to reconstruct a high resolution iris image from a video sequence of an eye. A novel fusion approach is proposed to incorporate information details from multiple frames using robust mean. Experiments on the MBGC NIR portal database show the validity of the proposed approach in comparison with other resolution enhancement techniques.