1. Articles in category: Dentistry

    1-24 of 349 1 2 3 4 ... 13 14 15 »
    1. MicroCT and optical coherence tomography imagistic assessment of the dental roots adhesive

      MicroCT and optical coherence tomography imagistic assessment of the dental roots adhesive

      Several obturation methods are available today to study the 3D filling of the root canal. There are also several methods capable to evaluate the ability to seal apically the root canals. However, the common methods of investigation are invasive; they also lead to the destruction of the samples. If the sectioning differs slightly from the desired area, the investigation is non-conclusive regarding the micro-leakages. Also, although the use of Cone-Beam Micro Computer Tomography (CBCT) appears to be most promising for endodontic purposes, its effective radiation doses are higher than with conventional intra-oral and panoramic imaging. In contrast, enface (ef) Optical ...

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    2. Application of swept-source optical coherent tomography to caries diagnosis

      Application of swept-source optical coherent tomography to caries diagnosis

      Swept-source optical coherence tomography(SS-OCT) is a new imaging technology using optical light with the wavelengths around 1300nm. The SS-OCT provides us the 3 dimensional image with much higher resolution than dental X-ray. The extent of caries lesion is very clearly observed in the obtained image. The purposes of this article is to introduce the recent research on the SS-OCT imaging of tooth and to discuss the possibility of clinical application of the SS-OCT for diagnosing occlusal caries, inter-proximal caries, recurrent caries, root caries, cracks, and monitoring the early caries lesion.

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    3. Surface pre-conditioning with bioactive glass air-abrasion can enhance enamel white spot lesion remineralization

      Surface pre-conditioning with bioactive glass air-abrasion can enhance enamel white spot lesion remineralization

      Objective To evaluate the effect of pre-conditioning enamel white spot lesion (WSL) surfaces using bioactive glass (BAG) air-abrasion prior to remineralization therapy. Methods Ninety human enamel samples with artificial WSLs were assigned to three WSL surface pre-conditioning groups ( n = 30): (a) air-abrasion with BAG-polyacrylic acid (PAA-BAG) powder, (b) acid-etching using 37% phosphoric acid gel (positive control) and (c) unconditioned (negative control). Each group was further divided into three subgroups according to the following remineralization therapy ( n = 10): (I) BAG paste (36 wt.% BAG), (II) BAG slurry (100 wt.% BAG) and (III) de-ionized water (negative control). The average surface roughness and ...

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    4. Automated detection of dentinal lesions in OCT images using the RKT transformation

      Automated detection of dentinal lesions in OCT images using the RKT transformation

      Several studies have shown that optical coherence tomography (OCT) can be used to measure the remaining enamel thickness and detect the location of subsurface lesions hidden under the sound enamel. The purpose of this study was to develop algorithms to enhance the visibility of subsurface structures such as hidden occlusal lesions and the dentinal-enamel junction. Extracted teeth with natural occlusal lesions were imaged with OCT with and without added high index fluids. A Rotating Kernel Transformation (RKT) nonlinear image processing filter was applied to PS-OCT images to enhance the visibility of the subsurface lesions under the sound enamel. The filter ...

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    5. Apices of maxillary premolars observed by swept source optical coherence tomography

      Apices of maxillary premolars observed by swept source optical coherence tomography

      Apicoectomy is performed for the management of apical periodontitis when orthograde root canal treatment is not possible or is ineffective. Prior to the surgery, cone beam computed tomography (CBCT) examination is often performed to evaluate the lesion and the adjacent tissues. During the surgical procedure, the root apex is resected and the resected surface is usually observed under dental operating microscope (DOM). However, it is difficult to evaluate the details and the subsurface structure of the root using CBCT and DOM. A new diagnostic system, swept source optical coherence tomography (SS-OCT), has been developed to observe the subsurface anatomical structure ...

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    6. Observation of the pulp horn by swept source optical coherence tomography and cone beam computed tomography

      Observation of the pulp horn by swept source optical coherence tomography and cone beam computed tomography

      Cone-beam computed tomography (CBCT) is one of the most useful diagnostic techniques in dentistry but it involves ionizing radiation, while swept source optical coherence tomography (SS-OCT) has been introduced recently as a nondestructive, real-time, high resolution imaging technique using low-coherence interferometry, which involves no ionizing radiation. The purpose of this study was to evaluate the ability of SS-OCT to detect the pulp horn (PH) in comparison with that of CBCT. Ten extracted human mandibular molars were used. After horizontally removing a half of the tooth crown, the distance from the cut dentin surface to PH was measured using microfocus computed ...

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    7. Assessment of defects at tooth/self-adhering flowable composite interface using swept-source optical coherence tomography (SS-OCT)

      Assessment of defects at tooth/self-adhering flowable composite interface using swept-source optical coherence tomography (SS-OCT)

      Abstract Objectives Assessment of adhesive defects of a self-etch adhesive and a self-adhering flowable composite at the tooth/composite interface before and after water storage by optical coherence tomography (OCT). Methods 16 extracted human molars ( n = 8 each) with box-shaped, class-V cavities were restored either with an experimental self-adhering flowable composite (EF, DMG) or with the filling system Adper™ Prompt™ L-Pop™/Filtek™ Supreme XT Flowable composite (PLP, 3M ESPE). Restorations of both groups were non-invasively imaged using swept-source OCT before and after storage in water. The OCT signal for adhesive defects at the tooth/composite interface was quantified. Results At ...

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    8. Sensing of Tooth Microleakage Based on Dental Optical Coherence Tomography

      Sensing of Tooth Microleakage Based on Dental Optical Coherence Tomography

      This study describes microleakage sensing based on swept-source optical coherence tomography (SS-OCT). With a handheld scanning probe, the SS-OCT system can provide portable real-time imaging for clinical diagnosis. Radiography is the traditional clinical imaging instrument used for dentistry; however, it does not provide good contrast images between filling material and the enamel of treated teeth with microleakage. The results of this study show that microleakage can be detected with oral probing using SS-OCT in vivo . The calculated microleakage length was 401  μ m and the width is 148  μ m, which is consistent with the related histological biopsy measurements. The diagnosis of ...

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    9. Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

      Assessment of natural enamel lesions with optical coherence tomography in comparison with microfocus x-ray computed tomography

      A technology to characterize early enamel lesions is needed in dentistry. Optical coherence tomography (OCT) is a noninvasive method that provides high-resolution cross-sectional images. The aim of this study is to compare OCT with microfocus x-ray computed tomography ( μ CT ) for assessment of natural enamel lesions in vitro . Ten human teeth with visible white spot-like changes on the enamel smooth surface and no cavitation (ICDAS code 2) were subjected to imaging by μCT (SMX-100CT, Shimadzu) and 1300-nm swept-source OCT (Dental SS-OCT, Panasonic Health Care). In μ CT , the lesions appeared as radiolucent dark areas, while in SS-OCT, they appeared as areas of ...

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    10. Optical coherence tomography for evaluation of enamel and protective coatings

      Optical coherence tomography for evaluation of enamel and protective coatings

      Optical coherence tomography (OCT) is an interferometric imaging technique. This study aimed to employ OCT to evaluate four different resin-based materials including a coating containing glass-ionomer filler and calcium, a giomer, and two fluoride-releasing self-etch resins. The coating and its underlying and adjacent enamel were monitored using swept-source OCT (center wavelength: 1330 nm) at baseline, after 5,000 thermal cycles, and after 1, 4 and 7 days of demineralization (pH 4.5). The coatings showed different thicknesses (60–250 micrometers) and various levels of structural and interfacial integrity. OCT could detect a demineralization inhibition zone adjacent to the edge of ...

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    11. Failure analysis of adhesive restorations with SEM and OCT: from marginal gaps to restoration loss

      Failure analysis of adhesive restorations with SEM and OCT: from marginal gaps to restoration loss

      Objective The objective of this study was to analyse the failure mode of adhesive interfaces by comparing OCT and scanning electron microscope (SEM) analysis of class V restoration margins located on enamel and dentin. Materials and methods Three groups were tested that differed in the application of a 3-step etch-and-rinse adhesive system (OptiBond FL) prior to cavity filling with restorative composite resin (Clearfil AP-X). After tooth restoration and polishing, the samples were loaded in a fatigue machine, and adhesive interfaces were evaluated with OCT and SEM. Results Important and complementary information could be obtained with OCT analysis in respect to ...

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    12. PhD Fellowship in Dental Optical Coherence Tomography in the Department of Odontology at the University of Copenhagen

      PhD Fellowship in Dental Optical Coherence Tomography in the Department of Odontology at the University of Copenhagen

      Applications are invited for a PhD fellowship at the Department of Odontology, Faculty of Health and Medical Sciences, University of Copenhagen. The candidate will work in the area of digital dental scanning with focus on optical coherence tomography (OCT). The position is for a 3-year period and will commence on 1 May 2015 or as soon as possible thereafter. Project description The project is part of a research programme between Industry, Technical University of Denmark (DTU) and the Department of Odontology, University of Copenhagen. The objective of the project is to evaluate the clinical feasibility and reliability of OCT scanning ...

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    13. Internal fit of pressed and computer-aided design/computer-aided manufacturing ceramic crowns made from digital and conventional impressions

      Internal fit of pressed and computer-aided design/computer-aided manufacturing ceramic crowns made from digital and conventional impressions

      Statement of problem No studies have evaluated the internal adaptation of pressed and milled ceramic crowns made from digital impressions. Purpose The purpose of this in vitro study was to evaluate the internal fit of pressed and milled ceramic crowns made from digital and conventional impressions. Material and methods Thirty polyvinyl siloxane (PVS) impressions and 30 Lava COS impressions made of a prepared dentoform tooth (master die) were fabricated. Thirty crowns were pressed in lithium disilicate (IPS e.max Press), and 30 crowns were milled from lithium disilicate blocks (IPS e.max CAD) (15/impression technique) with the E4D scanner ...

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    14. Clinical assessment of non carious cervical lesion using swept-source optical coherence tomography

      Clinical assessment of non carious cervical lesion using swept-source optical coherence tomography

      ( A ) We determined the attenuation coeffcient (μ t ) threshold of SS-OCT signal for the detection of demineralization (1.21) from in vitro study. DEM: demineralized dentin, sound: sound dentin. ( B ) Using the μ t threshold, we observed NCCLs in vivo to detect the demineralization in cervical dentin. SS-OCT scanning was performed along the red line. ( C ) SS-OCT image obtained along the red line in B. In SS-OCT, brightness of dentin beneath the NCCL was increased (arrow) compared with intact zone. The cervical dentin was slightly demineralized (μ t : 1.25). e: enamel, d: dentin, g: gingiva. Non-carious cervical lesions (NCCLs) involve various forms ...

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    15. Development of an electro-optically tuned optical coherence tomography system for imaging dental lesions

      Development of an electro-optically tuned optical coherence tomography system for imaging dental lesions

      A conventional optical coherence tomography (OCT) system was set up in-house to image early dental caries, identify gap formation in the bonding interface for restoration and secondary caries. Two-dimensional images of tooth samples was obtained and dental defect were identified. A novel electro-optic tuning system is proposed in order to improve scanning speed and to perform noiseless imaging. Preliminary studies were conducted with two crystals namely, LiNbO 3 (Lithium Niobate) and KTP (Potassium Titanyl Phosphate) using a SLED source for OCT system and the simulated and experimental results were found to be qualitatively similar. The tuning range for LiNbO 3 ...

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    16. Assessment of the sealant/tooth interface using optical coherence tomography

      Assessment of the sealant/tooth interface using optical coherence tomography

      Sealant materials are typically employed in dentistry in order to prevent the development of cavities on the teeth. They prevent bacterial adhesion to enamel, thus arresting the development of demineralization and of caries. In this study, the critical zone of the interface between different sealant materials and the results of the dental work for the teeth processed were investigated ex vivo using swept source (SS) optical coherence tomography (OCT). Optical inspection and X-ray investigation revealed no defects, while SS-OCT proved capable to asses exactly the position, the nature, and the dimensions of each type of these defects. Specifically, different failures ...

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    17. Optical Coherence Tomography: A new era in dentistry

      Optical Coherence Tomography: A new era in dentistry

      Dental prostheses are very complex systems, heterogenous in structure, made up from various materials, with different physical properties. They have to satisfy high stress requirements as well as aesthetic challenges. The failures of dental prostheses lead to functional, aesthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. OCT is a tomography imaging technology capable of producing high-resolution cross-sectional images of the internal architecture of materials and tissues. This includes not only the images of normal and abnormal dental hard tissue structures but also teeth after several treatment methods. It can be used for non-invasive investigations for both in-vivo ...

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    18. High contrast imaging of early demineralization on enamel surfaces using near-infrared polarized reflectance at lambda= 1460 and 1550 nm (Thesis)

      High contrast imaging of early demineralization on enamel surfaces using near-infrared polarized reflectance at lambda= 1460 and 1550 nm (Thesis)

      Introduction: In vivo and in vitro studies have shown that high contrast images of tooth demineralization can be acquired in the near-infrared at several wavelengths. The purpose of this study is to compare the lesion contrast in reflectance at near-infrared wavelengths coincident with high water absorption with those in the visible, the near-infrared at 1300nm, fluorescence, and polarization sensitive optical coherence tomography (PS-OCT) measurements for early lesions on buccal surfaces. Methods: Bovine incisors (n=40) were used in this in vitro study. Teeth were sectioned so that they were greater than 8mm in length, 2mm in width, and had at ...

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      Mentions: UCSF
    19. Evaluation of the effects of fluoride-releasing varnish on dentin demineralization using optical coherence tomography

      Evaluation of the effects of fluoride-releasing varnish on dentin demineralization using optical coherence tomography

      Effects of a fluoride-releasing varnish containing surface reaction-type prereacted glass ionomer (S-PRG) filler on dentin demineralization were examined using optical coherence tomography. Bovine incisors that were sliced and treated with undersaturated 0.1 M lactic acid buffer solution (DE group). A thin film of varnish-containing S-PRG filler was applied before demineralization (PRG group). Control was maintained in artificial saliva. Using optical coherence tomography of selected locations on the dentin surface, peak intensity (dB) and width (μm) at 1/e 2 were obtained and integrated values calculated. Although alterations in integrated values were different in each group, there was a slight ...

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    20. Detection of a Second Mesiobuccal Canal in Maxillary Molars by Swept-source Optical Coherence Tomography

      Detection of a Second Mesiobuccal Canal in Maxillary Molars by Swept-source Optical Coherence Tomography

      Introduction The purpose of this study was to investigate the ability of swept-source optical coherence tomographic (SS-OCT) imaging to detect a second mesiobuccal canal (MB2) in maxillary molars compared with visual inspection (VI) and dental operating microscopy (DOM). Methods Forty extracted human maxillary molars were examined. After the removal of half the crown and access cavity preparation, the existence of MB2 canals was confirmed based on cross-sectional images of each tooth obtained by micro–computed tomographic scanning as the reference standard. Then, the pulp chamber floor was scanned by SS-OCT imaging. Three dentists independently evaluated the SS-OCT images and the ...

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    21. Evaluation of two quantitative analysis methods of optical coherence tomography for detection of enamel demineralization and comparison with microhardness

      Evaluation of two quantitative analysis methods of optical coherence tomography for detection of enamel demineralization and comparison with microhardness

      Background and Objective We aimed to evaluate in the same study two quantitative methods for quantification of incipient caries in human dental enamel by using optical coherence tomography (OCT): the optical attenuation coefficient and the area under the A-scan signal, and to compare their results with those obtained from microhardness analysis. Study Design/Materials and Methods One hundred and sixty samples were obtained from 40 sound human third molars, which had their crowns sectioned. Simulated caries were created by a pH cycling method. OCT measurements were performed on the samples, before and after the induced demineralization. We determined the total ...

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    22. Comparing the In Vivo Diagnostic Accuracy of Digital Periapical Radiography with Cone-beam Computed Tomography for the Detection of Vertical Root Fracture

      Comparing the In Vivo Diagnostic Accuracy of Digital Periapical Radiography with Cone-beam Computed Tomography for the Detection of Vertical Root Fracture

      Introduction The purpose of this study was to determine whether there is a difference in the in vivo diagnostic accuracy of digital radiography (DR) and cone-beam computed tomography (CBCT) imaging in the detection of vertical root fracture (VRF). The presence/absence of VRF was confirmed by visual inspection of the extracted root surface and was the reference standard against which both imaging modalities were compared. Methods Twenty-one unsalvageable teeth from 20 patients that had been radiographed and scanned with CBCT imaging were included in the study. The teeth were atraumatically extracted and visually inspected under a microscope to confirm the ...

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    23. A method for monitoring enamel erosion using laser irradiated surfaces and optical coherence tomography

      A method for monitoring enamel erosion using laser irradiated surfaces and optical coherence tomography

      Introduction Since optical coherence tomography (OCT) is well suited for measuring small dimensional changes on tooth surfaces, OCT has great potential for monitoring tooth erosion. Previous studies have shown that enamel areas ablated by a carbon dioxide laser manifested lower rates of erosion compared to the non-ablated areas. The purpose of this study was to develop a model to monitor erosion in vitro that could potentially be used in vivo . Methods Thirteen bovine enamel blocks were used in this in vitro study. Each 10 mm × 2 mm block was partitioned into five regions, the central region was unprotected, the adjacent ...

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