1. Articles in category: Dentistry

    1-24 of 421 1 2 3 4 ... 16 17 18 »
    1. Assessing the dynamic biofilm removal of sulfonated phenolics using CP-OCT

      Assessing the dynamic biofilm removal of sulfonated phenolics using CP-OCT

      Examining the physical mechanisms related to biofilm removal of sulfonated phenolics (SP) is difficult using conventional microscopy techniques. A custom flow cell system integrated with a real time cross polarization optical coherence tomography system investigated the dynamic speed of biofilm removal when oral multi-species biofilms are exposed to SP under sheer stress. The Near infrared 1310-nm CP-OCT system non-destructively imaged fluid immersed oral biofilms at nearly 30 frames/s. This dynamic imaging was able to determine the cohesive and adhesion related disruption of SP on oral biofilms adhering to tooth like surfaces. For multi-species biofilms that are initially grown without ...

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    2. Characterization of human oral tissues based on quantitative analysis of optical coherence tomography images

      Characterization of human oral tissues based on quantitative analysis of optical coherence tomography images

      In this paper, five types of tissues, human enamel, human cortical bone, human trabecular bone, muscular tissue, and fatty tissue were imaged ex vivo using optical coherence tomography (OCT). The specimens were prepared in blocks of 5 x 5 x 3 mm (width x length x height). The OCT imaging system was a swept source OCT system operating at wavelengths ranging between 1250 nm and 1360 nm with an average power of 18 mW and a scan rate of 50 to 100 kHz. The imaging probe was placed on top of a 2 x 2 cm stabilizing device to maintain ...

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    3. Resolution characteristics of optical coherence tomography for dental use

      Resolution characteristics of optical coherence tomography for dental use

      OBJECTIVES: The purpose of this study was to clarify resolution characteristics of optical coherence tomography (OCT) for dental use. METHODS: Two types of swept-source OCT machines (SS-OCTs) were employed in this study. To clarify their resolution characteristics, we newly developed a glass chart device with a ladder pattern of wavelengths, which ranged from (4 x 2) µm to (1024 x 2) µm, as well as a star-target pattern, a grid pattern, and a spatial frequency response pattern. The resolving powers and characteristics of the OCTs were subjectively evaluated. RESULTS: The Santec OCT had a resolving power of 64 µm in ...

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    4. Optical Coherence Technology Detects Early Signs of Peri-implant Mucositis in the Minipig Model

      Optical Coherence Technology Detects Early Signs of Peri-implant Mucositis in the Minipig Model

      Background: Peri-implant mucositis defines the inflammation of gingival tissue surrounding osseous integrated implants without destruction of supporting bone. Untreated mucositis may develop into peri-implantitis with irreversible resorption of alveolar bone and implant failure. Mucositis is reversible with early intervention; however, existing clinical approaches have proved inadequate to reveal initial stages of this complication. Optical Coherence Tomography (OCT) is a non-invasive modality that provides real time, cross-sectional optical images of tissue up to 2-3mm in depth from the surface. Here, the minipig model assessed the diagnostic capability of OCT to detect early signs of mucositis by imaging microstructural changes of soft ...

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    5. Optical coherence tomography for early detection of dental diseases: In vitro and in vivo feasibility studies ( Thesis)

      Optical coherence tomography for early detection of dental diseases: In vitro and in vivo feasibility studies ( Thesis)

      nflammation of the gums and tooth decay are conditions that, if detected early enough, can be corrected or reversed. There is therefore a need for minimally invasive, accurate assessment of dental and periodontal tissue in order to achieve prompt diagnosis and treatment. Optical coherence tomography (OCT) is an emerging non-invasive, non-ionizing imaging modality that provides cross-sectional images of tissue, up to several millimeters in depth with micrometer level resolution. The underlying hypothesis of this thesis is that biological alterations to oral tissues result in changes in light scattering behavior which could be quantified by OCT. In vitro bovine tooth samples ...

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    6. A pilot study to assess the morphology and progression of non-carious cervical lesions

      A pilot study to assess the morphology and progression of non-carious cervical lesions

      Objective This longitudinal pilot study aimed to morphologically and quantitatively investigate the progress of non-carious cervical lesions (NCCLs) by using swept-source optical coherence tomography (SS-OCT). Methods The samples examined comprised sets of NCCL epoxy resin replicas obtained from 10 lesions in 6 patients who attended annual dental visits over 4 or 5 years. SS-OCT images of the replicas were analyzed in terms of the maximum depth (D max ) and corresponding vertical width (VW) − using an image analyzer to estimate progression of the NCCLs over time. Results It was found that differences between wedge- and saucer-shaped lesions were morphologically distinguished well ...

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    7. Bio-Photonic Detection and Quantitative Evaluation Method for the Progression of Dental Caries Using Optical Frequency-Domain Imaging Method

      Bio-Photonic Detection and Quantitative Evaluation Method for the Progression of Dental Caries Using Optical Frequency-Domain Imaging Method

      The initial detection of dental caries is an essential biomedical requirement to barricade the progression of caries and tooth demineralization. The objective of this study is to introduce an optical frequency-domain imaging technique based quantitative evaluation method to calculate the volume and thickness of enamel residual, and a quantification method was developed to evaluate the total intensity fluctuation in depth direction owing to carious lesions, which can be favorable to identify the progression of dental caries in advance. The cross-sectional images of the ex vivo tooth samples were acquired using 1.3 μm spectral domain optical coherence tomography system (SD-OCT ...

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    8. Three-Dimensional Analysis of Enamel Crack Behavior Using Optical Coherence Tomography

      Three-Dimensional Analysis of Enamel Crack Behavior Using Optical Coherence Tomography

      The aim of this study was to nondestructively analyze enamel crack behavior on different areas of teeth using 3D swept source-optical coherence tomography (SS-OCT). Ten freshly extracted human teeth of each type on each arch ( n = 80 teeth) were inspected for enamel crack patterns on functional, contact and nonfunctional, or noncontact areas using 3D SS-OCT. The predominant crack pattern for each location on each specimen was noted and analyzed. The OCT observations were validated by direct observations of sectioned specimens under confocal laser scanning microscopy (CLSM). Cracks appeared as bright lines with SS-OCT, with 3 crack patterns identified: Type I ...

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    9. Optical analysis of enamel and dentin caries in relation to mineral density using swept-source optical coherence tomography

      Optical analysis of enamel and dentin caries in relation to mineral density using swept-source optical coherence tomography

      The aim of this study was to evaluate the signal intensity and signal attenuation of swept source optical coherence tomography (SS-OCT) for dental caries in relation to the variation of mineral density. SS-OCT observation was performed on the enamel and dentin artificial demineralization and on natural caries. The artificial caries model on enamel and dentin surfaces was created using Streptococcus mutans biofilms incubated in an oral biofilm reactor. The lesions were centrally cross sectioned and SS-OCT scans were obtained in two directions to construct a three-dimensional data set, from the lesion surface (sagittal scan) and parallel to the lesion surface ...

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    10. Method and apparatus for measuring and displaying dental plaque

      Method and apparatus for measuring and displaying dental plaque

      A method and an apparatus for measuring and displaying dental plaque are provided, and the method includes the steps of dividing near infrared light output from a light source into measurement light and reference light, applying the measurement light toward a tooth in an oral cavity and scanning the tooth with the measurement light, producing interference light from reflected light and back-scattered light from the tooth and the reference light, generating an optical coherence tomographic image based on a scattering intensity value of the interference light, extracting a dental plaque region having a specific scattering intensity value from the optical ...

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    11. Progression of erosive lesions after Nd:YAG laser and fluoride using optical coherence tomography

      Progression of erosive lesions after Nd:YAG laser and fluoride using optical coherence tomography

      This study aimed to use optical coherence tomography (OCT) to assess the progression of erosive lesions after irradiation with Nd:YAG laser and application of topical fluoride. One-hundred and twenty dentin samples (4 × 4 × 2 mm) obtained from bovine incisors were used. Samples were protected with acid-resistant nail varnish, with exception of a central circular area 2 mm in diameter. All samples were submitted to erosive cycles with citric acid solution 0.05 M (citric acid monohydrate—C6H8O7·H2O); M = 210.14 g/mol) pH 2.3, at room temperature, for 20 min, 2×/day, throughout 20 days. After 10 ...

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    12. Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography

      Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography

      Objective The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques. Material and Methods Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light ...

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      Mentions: Thorlabs
    13. In vivo assessment of periodontal structures and measurement of gingival sulcus with Optical Coherence Tomography: a pilot study

      In vivo assessment of periodontal structures and measurement of gingival sulcus with Optical Coherence Tomography: a pilot study

      There has been increasing interest on the development of clinically acceptable, more sensitive and specific methods for non-invasive diagnosis in Periodontics. In this pilot study, the performance of an Optical Coherence Tomography (OCT) system in imaging periodontal structures in humans was evaluated. Gingival sulcus depth measurements were obtained and compared with traditional probes. In total, 445 sites of 23 periodontally healthy individuals were measured by 3 instruments: North Carolina manual probe, Florida automated probe and OCT at 1325 nm. To obtain quantitative measurements from OCT images, the gingival refractive index was also determined. Discomfort/pain perception and the duration of ...

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    14. Enamel Thickness Determination by Optical Coherence Tomography: In vitro Validation

      Enamel Thickness Determination by Optical Coherence Tomography: In vitro Validation

      Optical coherence tomography (OCT) has been introduced in dentistry as a nondestructive diagnostic imaging tool that does not utilize ionizing radiation. This study investigated the agreement between polarization-sensitive OCT (PS-OCT), microcomputed tomography (μ-CT), and histology for enamel thickness measurements. Human enamel samples were prepared and evaluated with μ-CT and PS-OCT and then sectioned and observed via digital transversal light microscopy. For all methods, a standard transversal section (b-scan) in each sample was selected, and the enamel thickness was measured at three predetermined positions using ImageJ analysis software. The results revealed significant high agreement between all tested methods, indicating the potential ...

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    15. Assessment of bacterial demineralization around composite restorations using swept-source optical coherence tomography (SS-OCT)

      Assessment of bacterial demineralization around composite restorations using swept-source optical coherence tomography (SS-OCT)

      Objective To observe the bacterial demineralization of the enamel and dentin around composite restorations bonded with one-step and two-step self-etch adhesive systems using swept-source optical coherence tomography (SS-OCT). Methods Forty class V cavities (2.5-mm surface diameter, 2.0-mm maximum depth) were prepared on cervical areas of 20 human molars. The specimens were either treated with one-step adhesive (Clearfil Tri-S Bond ND Quick; TS) or two-step adhesive (Clearfil SE Bond; SE), restored with a flowable resin composite (Estelite Flow Quick). Specimens in the demineralized group were incubated for 2 weeks after Streptococcus mutans biofilm formation, while specimens in the control ...

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    16. Monitoring of cariogenic demineralization at the enamel–composite interface using swept-source optical coherence tomography

      Monitoring of cariogenic demineralization at the enamel–composite interface using swept-source optical coherence tomography

      Objectives The aim of this study was to evaluate enamel demineralization at composite restoration margins caused by cariogenic biofilm using swept-source optical coherence tomography (SS-OCT). Methods Sixty round-shaped cavities were prepared on the mid-buccal enamel surface of extracted human molars. The cavities were restored with Estelite Flow Quick flowable composite using either Clearfil SE Bond or Clearfil Tri-S Bond ND bonding agents. Streptococcus mutans suspension was applied to form a cariogenic biofilm on the surface. After 1, 2, or 3 weeks of incubation ( n = 10), the biofilm was removed to observe the carious demineralization at the cavosurface margins using SS-OCT ...

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    17. Internal adaptation of resin composites at two configurations: Influence of polymerization shrinkage and stress

      Internal adaptation of resin composites at two configurations: Influence of polymerization shrinkage and stress

      Objective This study compared internal adaptation of composites under different C-factors and examined the relationship between internal adaptation and polymerization shrinkage parameters. Methods Cylindrical cavities 3 mm in diameter were prepared in 100 human third molars in two depths: 4 mm high C-factor (H-CF) or 1 mm low C-factor (L-CF). After adhesive application (Clearfil SE One, Kuraray Noritake), the composite was placed in two increments in three subgroups: Filtek Supreme (FS, 3 M ESPE); Charisma Diamond (CD, Heraeus Kulzer); Amelogen Plus (AP, Ultradent); and as a single increment in two subgroups: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent) and Venus ...

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    18. The role of enamel thickness and refractive index on human tooth colour

      The role of enamel thickness and refractive index on human tooth colour

      Objectives To investigate the role of enamel thickness and refractive index ( n ) on tooth colour. Methods The colour and enamel thickness of fifteen extracted human central incisors were determined according to CIELab colour scale using spectrophotometer (Crystaleye) and swept-source optical coherence tomography (SS-OCT), respectively. Subsequently, labial enamel was trimmed by approximately 100 μm, and the colour and remaining enamel thickness were investigated again. This cycle was repeated until dentin appeared. Enamel blocks were prepared from the same teeth and their n were obtained using SS-OCT. Multiple regression analysis was performed to reveal any effects of enamel thickness and n on ...

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    19. Assessment of occlusal fissure depth and sealant penetration using optical coherence tomography

      Assessment of occlusal fissure depth and sealant penetration using optical coherence tomography

      Swept source optical coherence tomography (SS-OCT) is an interferometric imaging technique. This study aimed to assess SS-OCT as a diagnostic tool for the evaluation of occlusal fissure depth and sealant penetration into fissure. Seventy investigation sites of occlusal fissures without visible evidence of caries were categorized into four groups (smooth, shallow, intermediate, and deep fissures). Categorization utilized two methods: 1) visually, using a computer screen, and 2) using SS-OCT images. After sealant placement, penetration was observed in SS-OCT. The results obtained from SS-OCT and visual inspections were compared with those of confocal laser scanning microscope (CLSM). The diagnostic power of ...

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    20. Ultrastructural features of dentinoenamel junction revealed by focused gallium ion beam milling

      Ultrastructural features of dentinoenamel junction revealed by focused gallium ion beam milling

      To take full advantage of focused ion beam (FIB) in preparation of ultrathin sections of biological tissues, we have used a cryo-milling process. In this study, extracted human teeth were scanned by optical coherence tomography to inspect the samples for intactness and to determine the area of interest. Then, the selected area of interest was cross-sectioned for examination under a confocal laser scanning microscope to determine the target location of the dentinoenamel junction (DEJ) that was later milled by cryo-FIB at preset parameters, followed by transmission electron microscope examination of the final sliced specimens for ultrastructural characterization. The proposed technique ...

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      Mentions: Turki Bakhsh
    21. 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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    22. 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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    23. 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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    24. 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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    1-24 of 421 1 2 3 4 ... 16 17 18 »
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