1. Articles in category: Dentistry

    1-24 of 401 1 2 3 4 ... 15 16 17 »
    1. Fractography of interface after microtensile bond strength test using swept-source optical coherence tomography

      Fractography of interface after microtensile bond strength test using swept-source optical coherence tomography

      Objective To determine the effect of crosshead speed and placement technique on interfacial crack formation in microtensile bond strength (MTBS) test using swept-source optical coherence tomography (SS-OCT). Materials and methods MTBS test beams (0.9 × 0.9 mm 2 ) were prepared from flat human dentin disks bonded with self-etch adhesive (Clearfil SE Bond, Kuraray) and universal composite (Clearfil AP-X, Kuraray) with or without flowable composite lining (Estelite Flow Quick, Tokuyama). Each beam was scanned under SS-OCT (Santec, Japan) at 1319 nm center wavelength before MTBS test was performed at crosshead speed of either 1 or 10 mm/min ( n = 10 ...

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    2. Tissue characterization using optical coherence tomography and cone beam computed tomography: A comparative pilot study

      Tissue characterization using optical coherence tomography and cone beam computed tomography: A comparative pilot study

      Objectives To evaluate the ability of optical coherence tomography (OCT) in differentiating between human oral tissues in comparison with cone beam computed tomography (CBCT). Study design In this study, we imaged four types of tissues ex vivo , i.e., human enamel, human cortical bone, human trabecular bone, fatty tissue plus water and air using OCT (Axsun Inc. Billerica, MA). We then developed a method for qualitative and quantitative analysis of the human specimens. The same types of tissues were also imaged using CBCT and grayscale values were measured. Results The qualitative indices (intensity profile, contour plot and histogram) for OCT ...

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    3. Activity assessment of root caries lesions with thermal and near-IR imaging methods

      Activity assessment of root caries lesions with thermal and near-IR imaging methods

      The purpose of this study was to evaluate thermal and near-infrared (NIR) reflectance imaging methods for the assessment of the activity of root caries lesions. In addition, changes in the lesion structure were monitored with polarization sensitive optical coherence tomography (PS-OCT). Artificial bovine and natural root caries lesions were imaged with PS-OCT, and their dehydration rate was measured with thermal and NIR cameras. The lesion activity of the natural root caries samples was also assessed by two clinicians by conventional means according to ICDAS II guidelines. The thickness of the highly mineralized transparent surface layer measured using PS-OCT increased and ...

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    4. Dental optical scanning device and dental optical scanning/diagnosing tool

      Dental optical scanning device and dental optical scanning/diagnosing tool

      An OCT measuring mechanism for acquiring the optical coherence tomography information and a surface shape measuring mechanism for acquiring the three-dimensional shape information share a display device, a control device, a light source, a scanning mirror, a light transmission/receiving path and an entering/exiting opening. The scanning mirror, the light transmission/receiving path, the entering/exiting opening are included in a handpiece operable to make a diagnosis on a diagnostic target site.

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    5. Assessment of dental plaque by optoelectronic methods

      Assessment of dental plaque by optoelectronic methods

      The formation of dental biofilm follows specific mechanisms of initial colonization on the surface, microcolony formation, development of organized three dimensional community structures, and detachment from the surface. The structure of the plaque biofilm might restrict the penetration of antimicrobial agents, while bacteria on a surface grow slowly and display a novel phenotype; the consequence of the latter is a reduced sensitivity to inhibitors. The aim of this study was to evaluate with different optoelectronic methods the morphological characteristics of the dental biofilm. The study was performed on samples from 25 patients aged between 18 and 35 years. The methods ...

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    6. Optical coherence tomography in oral cancer detection

      Optical coherence tomography in oral cancer detection

      Majority of oral cancers develop from potentially malignant lesions. The malignant transformation rates of oral premalignant lesions are reported to be 1-7% for homogeneous, thick leukoplakia, 4-15% for granular or verruciform leukoplakia, 18-47% for erythroleukoplakia, 4-11% for moderate dysplasia, and 20-35% for severe dysplasia.[1] The high rate of malignant transformation for potentially malignant lesions also indicates the importance of early diagnosis and early treatment. Most of the potentially malignant lesions are non-homogeneous in nature. Hyperkeratosis and acanthosis may be present in one part of the lesion while others areas may show epithelial dysplasia, carcinoma in situ, or invasive carcinoma ...

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    7. OCT evaluation of single ceramic crowns: comparison between conventional and chair-side CAD/CAM technologies

      OCT evaluation of single ceramic crowns: comparison between conventional and chair-side CAD/CAM technologies

      Digital impressions were introduced to overcome some of the obstacles due to traditional impression materials and techniques. The aim of this in vitro study is to compare the accuracy of all ceramic crowns obtained with digital impression and CAD-CAM technology with the accuracy of those obtained with conventional impression techniques. Two groups of 10 crowns each have been considered. The digital data obtained from Group 1 have been processed and the all-ceramic crowns were milled with a CAD/CAM technology (CEREC MCX, Sirona). The all ceramic crowns in Group 2 were obtained with the classical technique of pressing (emax, Ivoclar ...

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    8. Mitigation of enamel erosion using commercial toothpastes evaluated with optical coherence tomography

      Mitigation of enamel erosion using commercial toothpastes evaluated with optical coherence tomography

      The aim of this study was to evaluate the efficacy of commercial toothpastes containing sodium fluoride (NaF), stannous fluoride (SnF2), or casein phosphopeptides (CPP)-amorphous calcium phosphate (ACP)/NaF regarding their potential to inhibit enamel erosion. Twenty-eight 4×4 mm enamel specimens were randomly allocated into 4 groups (n=7): negative control; Pronamel (NaF); Pro Health (SnF 2 /NaF); Mi Paste Plus (CPP-ACP/NaF). Erosive cycles with 0.5% citric acid, 5 times, 3 minutes/day for 7 days were performed. After the first and last cycle of each day, toothpaste slurries were applied for 2 min. The quantitative analysis ...

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    9. Handheld scanning probes for optical coherence tomography: developments, applications, and perspectives

      Handheld scanning probes for optical coherence tomography: developments, applications, and perspectives

      We present the handheld scanning probes that we have recently developed in our current project for biomedical imaging in general and for Optical Coherence Tomography (OCT) in particular. OCT is an established, but dynamic imagistic technique based on laser interferometry, which offers micrometer resolutions and millimeters penetration depths. With regard to existing devices, the newly developed handheld probes are simple, light and relatively low cost. Their design is described in detail to allow for the reproduction in any lab, including for educational purposes. Two probes are constructed almost entirely from off-the-shelf components, while a third, final variant is constructed with ...

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    10. Optical coherence tomography based imaging of dental demineralisation and cavity restoration in 840 nm and 1310 nm wavelength regions

      Optical coherence tomography based imaging of dental demineralisation and cavity restoration in 840 nm and 1310 nm wavelength regions

      In this paper, a study of in-house built optical coherence tomography (OCT) system with a wavelength of 840 nm for imaging of dental caries, progress in demineralisation and cavity restoration is presented. The caries when imaged with the 840 nm OCT system showed minute demineralisation in the order of 5 μm. The OCT system was also proposed to study the growth of lesion and this was demonstrated by artificially inducing caries with a demineralisation solution of pH 4.8. The progress of carious lesion to a depth of about 50–60 μm after 60 hours of demineralisation was clearly observed ...

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    11. Enhancement of OCT images with vinyl polysiloxane (VPS)

      Enhancement of OCT images with vinyl polysiloxane (VPS)

      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. Moreover studies have shown that high refractive index liquids can be used to improve the visibility of subsurface lesions in OCT images. In this study, we demonstrate that vinyl polysiloxane (VPS) impression materials which are routinely used in dentistry can be used to enhance the detection of dentinal lesions on tooth occlusal surfaces. Lesion presence was confirmed with polarized light microscopy and microradiography.

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    12. Comparison of caries diagnostic modalities: A clinical study in 40 subjects

      Comparison of caries diagnostic modalities: A clinical study in 40 subjects

      Background and Objectives Few studies have been published that evaluate the usefulness of different caries- diagnostic modalities in general dental practice. The goal of this study was to compare the results of screening for coronal dental caries in a general dental practice using clinical observations, radiographs, laser fluorescence (DIAGNOdent™) (LF), and optical coherence tomography (OCT). Diagnostic agreement between OCT and LF versus standard clinical techniques for detecting caries was determined in 40 subjects. Study Designs/Materials and Methods Forty patients with >1 coronal carious lesion as determined by prescreening using clinical examination and radiographs were enrolled in this study. Subjects ...

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    13. Assessment of cervical demineralization induced by Streptococcus mutans using swept-source optical coherence tomography

      Assessment of cervical demineralization induced by Streptococcus mutans using swept-source optical coherence tomography

      Exposed root surfaces due to gingival recession are subject to biofilm stagnation that can result in caries formation. Cervical enamel and dentin demineralization induced by a cariogenic biofilm was evaluated using swept-source optical coherence tomography (SS-OCT). The cementoenamel junction (CEJ) sections of extracted human teeth were subjected to demineralization for 1, 2, or 3 weeks. A suspension of Streptococcus mutans was applied to form a cariogenic biofilm using an oral biofilm reactor. After incubation, demineralization was observed by SS-OCT. For the analysis of SS-OCT signal, the value of the area under the curve (AUC) of the signal profile was measured ...

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    14. Optical coherence tomography use in the diagnosis of enamel defects

      Optical coherence tomography use in the diagnosis of enamel defects

      Molar incisor hypomineralization (MIH) affects the permanent incisors and molars, whose undermineralized matrix is evidenced by lesions ranging from white to yellow/brown opacities to crumbling enamel lesions incapable of withstanding normal occlusal forces and function. Diagnosing the condition involves clinical and radiographic examination of these teeth, with known limitations in determining the depth extent of the enamel defects in particular. Optical coherence tomography (OCT) is an emerging hard and soft tissue imaging technique, which was investigated as a new potential diagnostic method in dentistry. A comparison between the diagnostic potential of the conventional methods and OCT was conducted. Compared ...

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    15. Clinical monitoring of smooth surface enamel lesions using CP-OCT during nonsurgical intervention

      Clinical monitoring of smooth surface enamel lesions using CP-OCT during nonsurgical intervention

      Introduction Studies have shown that cross-polarization optical coherence tomography (CP-OCT) can be used to image the internal structure of carious lesions in vivo . The objective of this study was to show that CP-OCT can be used to monitor changes in the internal structure of early active carious lesions on smooth surfaces during non-surgical intervention with fluoride. Methods Lesions on the smooth surfaces of teeth were imaged using CP-OCT on 17 test subjects. Lesion structural changes were monitored during fluoride varnish application at 6-week intervals for 30 weeks. The lesion depth ( L d ), integrated reflectivity (Δ R ), and surface zone thickness ( S ...

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    16. Optical coherence tomography investigations of ceramic lumineers

      Optical coherence tomography investigations of ceramic lumineers

      Lumineers are veneer laminates used as an alternative for aesthetic dental solutions of the highest quality, but the only current means of its performance assessment is visual inspection. The objective of this study was to use the Optical Coherence Tomography (OCT) technique working in spectral domain to analyze in vivo in a single patient, 14 lumineers 180 days after cementation. It was possible to observe images in various kinds of changes in the cementing line and the laminate. It was concluded that the OCT is an effective and promising method to clinical evaluation of the cementing line in lumineers.

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    17. Monitoring the gingival regeneration after aesthetic surgery with optical coherence tomography

      Monitoring the gingival regeneration after aesthetic surgery with optical coherence tomography

      The aim of this study was to use the Optical Coherence Tomography (OCT) technique working in spectral domain (Swept Source OCT at 1325 nm, Thorlabs, New Jersey, USA) to monitor the tissue repair in patients undergoing periodontal plastic surgery. The evaluations were done over a period of 60 days. It was observed that 15 days after periodontal surgery the gum was still in different healing process as compared to the observation after 60 days. Thus it is clear that, despite some technical limitations, the OCT is an efficient method in the evaluation of regeneration gingival.

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    18. Near-infrared imaging of secondary caries lesions around composite restorations at wavelengths from 1300–1700-nm

      Near-infrared imaging of secondary caries lesions around composite restorations at wavelengths from 1300–1700-nm

      Background and objectives Current clinical methods for diagnosing secondary caries are unreliable for identifying the early stages of decay around restorative materials. The objective of this study was to access the integrity of restoration margins in natural teeth using near-infrared (NIR) reflectance and transillumination images at wavelengths between 1300 and 1700-nm and to determine the optimal NIR wavelengths for discriminating composite materials from dental hard tissues. Materials and methods Twelve composite margins ( n = 12) consisting of class I, II and V restorations were chosen from ten extracted teeth. The samples were imaged in vitro using NIR transillumination and reflectance, polarization ...

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    19. Near-IR image-guided laser ablation of demineralization on tooth occlusal surfaces

      Near-IR image-guided laser ablation of demineralization on tooth occlusal surfaces

      Introduction Studies have shown that reflectance images at near-IR wavelengths coincident with higher water absorption are well-suited for image-guided laser ablation of carious lesions since the contrast between sound and demineralized enamel is extremely high and interference from stains is minimized. The objective of this study was to demonstrate that near-IR reflectance images taken at a wavelength range of 1,500–1,700 nm can be used to guide a 9.3 μm CO 2 laser for the selective ablation of early demineralization on tooth occlusal surfaces. Methods The occlusal surfaces of ten sound human molars were used in this ...

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    20. Effectiveness of fluoride sealant in the prevention of carious lesions around orthodontic brackets: an OCT evaluation

      Effectiveness of fluoride sealant in the prevention of carious lesions around orthodontic brackets: an OCT evaluation

      Objective: This article aimed to evaluate in vitro the efficiency of Pro Seal fluoride sealant application in the prevention of white spot lesions around orthodontic brackets. Material and Methods: Brackets were bonded to the buccal surface of bovine incisors, and five groups were formed (n = 15) according to the exposure of teeth to oral hygiene substances and the application of enamel sealant: G1 (control), only brushing was performed with 1.450 ppm fluoride; G2 (control) brushing associated with the use of mouthwash with 225 ppm fluoride; G3, only Pro Seal sealant application was performed with 1.000 ppm fluoride; G4 ...

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    21. Assessment of Self-Adhesive Resin Composites: Nondestructive Imaging of Resin–Dentin Interfacial Adaptation and Shear Bond Strength

      Assessment of Self-Adhesive Resin Composites: Nondestructive Imaging of Resin–Dentin Interfacial Adaptation and Shear Bond Strength

      Shear bond strength (SBS) and the interfacial adaptation (IA) of self-adhesive resin (SAR) composites to dentin were evaluated. Two SARs [Vertise Flow (VTF) and Fusio Liquid Dentin (FLD)] were evaluated and compared with a conventional restorative system [adhesive: OptiBond FL and composite: Herculite Précis (OBF/HP)]. Human third molars were used for SBS testing and IA imaging (n=7) using optical coherence tomography (OCT). Flattened dentin disks were prepared and the composites were applied into molds (2.4 mm diameter) that were positioned on dentin. Samples were subjected to SBS testing and OCT analysis, which considered an increase in ...

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    22. Non-destructive evaluation of an internal adaptation of resin composite restoration with swept-source optical coherence tomography and micro-CT

      Non-destructive evaluation of an internal adaptation of resin composite restoration with swept-source optical coherence tomography and micro-CT

      Swept-source optical coherence tomography (SS-OCT) and micro-CT can be useful non-destructive methods for evaluating internal adaptation. There is no comparative study evaluating the two methods in the assessment of internal adaptation in composite restoration. The purpose of this study was to compare internal adaptation measurements of SS-OCT and micro-CT. Two cylindrical cavities were created on the labial surface of twelve bovine incisors. The 24 cavities were randomly assigned to four groups of dentin adhesives: (1) three-step etch-and-rinse adhesive, (2) two-step etch-and-rinse adhesive, (3) two-step self-etch adhesive, and (4) one-step self-etch adhesive. After application, the cavities were filled with resin composite ...

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    23. Assessment of curing behavior of light-activated dental composites using intensity correlation based multiple reference optical coherence tomography

      Assessment of curing behavior of light-activated dental composites using intensity correlation based multiple reference optical coherence tomography

      Background and Objectives Monitoring the curing kinetics of light-activated resin is a key area of research. These resins are used in restorative applications and particularly in dental applications. They can undergo volumetric shrinkage due to poor control of the depth dependent curing process, modulated by the intensity and duration of the curing light source. This often results in the formation of marginal gaps, causing pain and damage to the restoration site. In this study, we demonstrate the capabilities of a correlation method applied using a multiple references optical coherence tomography (MR-OCT) architecture to monitor the curing of the resin. Study ...

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    24. Evaluation of Composite Adaptation to Pulpal Chamber Floor Using Optical Coherence Tomography

      Evaluation of Composite Adaptation to Pulpal Chamber Floor Using Optical Coherence Tomography

      Introduction A coronal seal is fundamental for a positive outcome to endodontic therapy. In this in vitro study, we evaluated the adaptation of composite resins in postendodontic restorations using optical coherence tomographic (OCT) imaging. Our null hypothesis was that there would be no difference in marginal adaptation to the pulp chamber floor between resin composites of different viscosities. Methods Thirty intact upper molars extracted for periodontal reasons were selected, endodontically treated, and filled with gutta-percha. The excess gutta-percha was entirely removed from the pulp chamber floor, and teeth were randomly divided into 3 groups ( n = 10) according to the material ...

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