1. Articles in category: Dentistry

    1-24 of 431 1 2 3 4 ... 16 17 18 »
    1. Assessment of enamel cracks at adhesive cavosurface margin using three-dimensional swept-source optical coherence tomography

      Assessment of enamel cracks at adhesive cavosurface margin using three-dimensional swept-source optical coherence tomography

      Objectives Swept-source optical coherence tomography (SS-OCT) can construct cross-sectional images of internal biological structures. The aim of this study was to evaluate enamel cracks at the cavosurface margin of composite restorations using SS-OCT. Methods Bowl-shaped cavities were prepared at two locations (mid-coronal and cervical regions) on the enamel surface of 60 bovine teeth. Half of the cavities (30) were treated with phosphoric acid gel. A two-step self-etch adhesive (Clearfil SE Bond) was applied to all cavities and a flowable composite was placed in bulk. After 7 days in water at 37 °C, three-dimensional (3D) images of the specimens were obtained ...

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    2. Cracked Teeth and Poor Oral Masticatory Habits: A Matched Case-control Study in China

      Cracked Teeth and Poor Oral Masticatory Habits: A Matched Case-control Study in China

      Introduction Previous studies have suggested that masticatory forces are associated with cracked teeth, but it is not clear which specific poor oral masticatory habits may be more likely to cause cracks. The aim of this study was to quantitatively assess risk factors for cracked teeth among poor oral masticatory habits and create a model for individualized risk predictions. Methods We enrolled 35 patients with cracked teeth matched to 70 controls without cracked teeth by age, sex, position of the affected tooth, presence/absence of systemic disease, and diagnosis of symptomatic irreversible pulpitis from the Stomatology Hospital of Tianjin Medical University ...

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    3. Detection of Apical Root Cracks Using Spectral Domain and Swept-source Optical Coherence Tomography

      Detection of Apical Root Cracks Using Spectral Domain and Swept-source Optical Coherence Tomography

      Introduction This study aimed to evaluate the ability of 2 optical coherence tomographic (OCT) systems to detect apical dentinal microcracks. Methods Twenty extracted human single-rooted mandibular incisors were selected. After root canal preparation with an R40 Reciproc file (VDW, Munich, Germany), the specimens presenting apical microcracks were identified using micro–computed tomographic (micro-CT) scanning as the gold standard. Then, the apical portions of the roots were imaged with spectral domain OCT (SD-OCT) and swept-source OCT systems, and the resulting images were blindly evaluated by 3 independent examiners to detect microcracks. The diagnostic performance of each OCT device was calculated, and ...

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    4. Near-IR and CP-OCT imaging of suspected occlusal caries lesions

      Near-IR and CP-OCT imaging of suspected occlusal caries lesions

      Introduction Radiographic methods have poor sensitivity for occlusal lesions and by the time the lesions are radiolucent they have typically progressed deep into the dentin. New more sensitive imaging methods are needed to detect occlusal lesions. In this study, cross-polarization optical coherence tomography (CP-OCT) and near-IR imaging were used to image questionable occlusal lesions (QOC's) that were not visible on radiographs but had been scheduled for restoration on 30 test subjects. Methods Near-IR reflectance and transillumination probes incorporating a high definition InGaAs camera and near-IR broadband light sources were used to acquire images of the lesions before restoration. The ...

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    5. Imaging Resin Infiltration into Non-Cavitated Carious Lesions by Optical Coherence Tomography

      Imaging Resin Infiltration into Non-Cavitated Carious Lesions by Optical Coherence Tomography

      Objectives Visualisation of the etching process and resin penetration at white spot carious lesions by spectral domain optical coherence tomography (SD-OCT). Materials and methods The non-cavitated carious lesions (ICDAS code 2) of four visually preselected extracted human molars and premolars were verified as enamel lesions by micro computed tomography (μCT). One region of interest (ROI) per tooth was marked by two drill-holes in occlusal-cervical direction. The lesions were imaged by SD-OCT. Lesions were infiltrated (Icon, DMG) according to the manufacturer’s instructions. During each treatment step and after light curing of the infiltrant, the ROIs were imaged again by SD-OCT ...

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    6. Automatic detection of tooth cracks in optical coherence tomography images

      Automatic detection of tooth cracks in optical coherence tomography images

      Purpose The aims of the present study were to compare the image quality and visibility of tooth cracks between conventional methods and swept-source optical coherence tomography (SS-OCT) and to develop an automatic detection technique for tooth cracks by SS-OCT imaging. Methods We evaluated SS-OCT with a near-infrared wavelength centered at 1,310 nm over a spectral bandwidth of 100 nm at a rate of 50 kHz as a new diagnostic tool for the detection of tooth cracks. The reliability of the SS-OCT images was verified by comparing the crack lines with those detected using conventional methods. After performing preprocessing of ...

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    7. Improved accuracy in periodontal pocket depth measurement using optical coherence tomography

      Improved accuracy in periodontal pocket depth measurement using optical coherence tomography

      Purpose The purpose of this study was to examine whether periodontal pocket could be satisfactorily visualized by optical coherence tomography (OCT) and to suggest quantitative methods for measuring periodontal pocket depth. Methods We acquired OCT images of periodontal pockets in a porcine model and determined the actual axial resolution for measuring the exact periodontal pocket depth using a calibration method. Quantitative measurements of periodontal pockets were performed by real axial resolution and compared with the results from manual periodontal probing. Results The average periodontal pocket depth measured by OCT was 3.10±0.15 mm, 4.11±0.17 mm ...

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    8. Evaluation of dermal fillers with noncontact optical coherence elastography

      Evaluation of dermal fillers with noncontact optical coherence elastography

      Over 2 million dermal filler procedures are performed each year in the USA alone, and this figure is only expected to increase as the aging population continues to grow. Dermal filler treatments can last from a few months to years depending on the type of filler and its placement. Although adverse reactions are rare, they can be quite severe due to ischemic events and filler migration. Previously, techniques such as ultrasound or magnetic resonance imaging have been used to evaluate the filler injections. However, these techniques are not practical for real-time filler injection guidance due to limitations such as the ...

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    9. Study on application to the field of dentistry using optical coherence tomography (OCT)

      Study on application to the field of dentistry using optical coherence tomography (OCT)

      Purpose This paper describes the basic principles and the feasibility of the field of dental diagnosis of optical coherence tomography (OCT) used in diverse field of medical diagnosis. Materials and methods In this review, the research data of OCT were searched from PubMed, medical journal and related papers. Results Generally, OCT is non-invasive and is possible to secure an excellent spatial resolution and real-time images of biological microstructure. Conclusion This review discusses not only the basic principles of operation, types, advantages, disadvantages of OCT but also the future applications of OCT technology and their potential in the field of dental ...

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    10. Enamel Thickness before and after Orthodontic Treatment Analysed in Optical Coherence Tomography

      Enamel Thickness before and after Orthodontic Treatment Analysed in Optical Coherence Tomography

      Despite the continuous development of materials and techniques of adhesive bonding, the basic procedure remains relatively constant. The technique is based on three components: etching substance, adhesive system, and composite material. The use of etchants during bonding orthodontic brackets carries the risk of damage to the enamel. Therefore, the article examines the effect of the manner of enamel etching on its thickness before and after orthodontic treatment. The study was carried out in vitro on a group of 80 teeth. It was divided into two subgroups of 40 teeth each. The procedure of enamel etching was performed under laboratory conditions ...

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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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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    16. 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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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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
    23. 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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    24. 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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    1-24 of 431 1 2 3 4 ... 16 17 18 »
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