1. Articles in category: Dentistry

    1-24 of 410 1 2 3 4 ... 15 16 17 »
    1. 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
    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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
    10. 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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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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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    16. 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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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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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    24. 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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    1-24 of 410 1 2 3 4 ... 15 16 17 »
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