1. Articles in category: Dentistry

    1-24 of 454 1 2 3 4 ... 17 18 19 »
    1. Quantitative measurement of peri-implant bone defects using optical coherence tomography

      Quantitative measurement of peri-implant bone defects using optical coherence tomography

      Purpose The purpose of this study was to visualize and identify peri-implant bone defects in optical coherence tomography (OCT) images and to obtain quantitative measurements of the defect depth. Methods Dehiscence defects were intentionally formed in porcine mandibles and implants were simultaneously placed without flap elevation. Only the threads of the fixture could be seen at the bone defect site in the OCT images, so the depth of the peri-implant bone defect could be measured through the length of the visible threads. To analyze the reliability of the OCT measurements, the flaps were elevated and the depth of the dehiscence ...

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    2. Optical coherence tomography to evaluate variance in the extent of carious lesions in depth

      Optical coherence tomography to evaluate variance in the extent of carious lesions in depth

      Evaluation of variance in the extent of carious lesions in depth at smooth surfaces within the same ICDAS code group using optical coherence tomography (OCT) in vitro and in vivo. (1) Verification/validation of OCT to assess non-cavitated caries: 13 human molars with ICDAS code 2 at smooth surfaces were imaged using OCT and light microscopy. Regions of interest (ROI) were categorized according to the depth of carious lesions. Agreement between histology and OCT was determined by unweighted Cohen’s Kappa and Wilcoxon test. (2) Assessment of 133 smooth surfaces using ICDAS and OCT in vitro, 49 surfaces in vivo ...

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    3. Evaluation of marginal gap of lithium disilicate glass ceramic crowns with optical coherence tomography

      Evaluation of marginal gap of lithium disilicate glass ceramic crowns with optical coherence tomography

      arginal gap (MG) was the most important factor to evaluate the success of crowns. The study was to assess the MG of lithium disilicate glass ceramic crowns with spectral domain optical coherence tomography (OCT) and stereomicroscopy in vitro , and to provide evidence to measure the MG with OCT. Consistency was observed between OCT and stereomicroscopy to measure the MG after cementation. There was no significant difference between the MG of lithium disilicate glass ceramic crowns using OCT and stereomicroscopy (OCT 59.55  ±  7.22   μ m, stereomicroscope 59.48  ±  6.53   μ m, P   =  0.736) after cementation. OCT was a noninvasive ...

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    4. Evaluation of the polymerization shrinkage of experimental flowable composite resins through optical coherence tomography

      Evaluation of the polymerization shrinkage of experimental flowable composite resins through optical coherence tomography

      This study evaluated the polymerization shrinkage of two experimental flowable composite resins (CR) with different proportions of Urethane dimethacrylate (UDMA)/triethylene glycol dimethacrylate (TEGDMA) monomers in the organic matrix (50:50 and 60:40, respectively). A commercially available flowable CR, Tetric N-Flow (Ivoclair Vivadent, Liechtenstein, Germany), was employed as the control group. The resins were inserted in a cylindrical teflon mold (7 mm diameter, 0.6 mm height) and scanned with OCT before photoactivation, immediately after and 15 minutes after light-curing (Radii-Cal, SDI, Australia, 1,200 mW/cm 2 ) exposure. A Callisto SD-OCT system (Thorlabs Inc, USA), operating at 930 ...

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    5. Silver nanoparticles as optical clearing agent enhancers to improve caries diagnostic by optical coherence tomography

      Silver nanoparticles as optical clearing agent enhancers to improve caries diagnostic by optical coherence tomography

      The use of silver nanoparticles as optical clearing agent (OCA) enhancers to improve caries diagnostic by optical coherence tomography (OCT) is demonstrated here. Five molars with no evident cavitation were selected. The OCAs were based on aqueous solution of silver nanoparticles (AgNP, 1.18x 10 14 particles/mL, ø ≈ 10nm) and its dilution at 10% in glycerol. Teeth were placed on a platform with a micrometric screw, and after applying the OCAs, they were scanned with a Callisto SD-OCT system operating ate 930nm central wavelength. The occlusal surfaces were scanned by OCT, capturing crosssectional images with 8 mm transversal scanning, generating ...

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    6. Effect of bioglass on artificially induced enamel lesion around orthodontic brackets: OCT study

      Effect of bioglass on artificially induced enamel lesion around orthodontic brackets: OCT study

      Background and Objective: White spot lesions (WSLs) are commonly seen after completing orthodontic treatment. Different approaches have been suggested to avoid such a complication. Recently, 45S5 bioglass (BG) was introduced as remineralizing agent. Therefore, the objective of this in-vitro study was to assess the effect of BG in remineralizing WSLs using Optical coherence tomography (OCT). Methods: Fifteen human premolar teeth were sectioned and bonded to orthodontic brackets with Transbond XT primer followed by Transbond PLUS color change adhesive (3M Unitek, USA) on their smooth surfaces according to the manufacturer’s instructions. Then, all specimens were varnished excluding the area of ...

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      Mentions: Turki Bakhsh
    7. Lesion dehydration rate changes with the surface layer thickness during enamel remineralization

      Lesion dehydration rate changes with the surface layer thickness during enamel remineralization

      A transparent highly mineralized outer surface zone is formed on caries lesions during remineralization that reduces the permeability to water and plaque generated acids. However, it has not been established how thick the surface zone should be to inhibit the penetration of these fluids. Near-IR (NIR) reflectance coupled with dehydration can be used to measure changes in the fluid permeability of lesions in enamel and dentin. Based on our previous studies, we postulate that there is a strong correlation between the surface layer thickness and the rate of dehydration. In this study, the rates of dehydration for simulated lesions in ...

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    8. Deep learning classifier with optical coherence tomography images for early dental caries detection

      Deep learning classifier with optical coherence tomography images for early dental caries detection

      Dental caries is a microbial disease that results in localized dissolution of the mineral content of dental tissue. Despite considerable decline in the incidence of dental caries, it remains a major health problem in many societies. Early detection of incipient lesions at initial stages of demineralization can result in the implementation of non-surgical preventive approaches to reverse the demineralization process. In this paper, we present a novel approach combining deep convolutional neural networks (CNN) and optical coherence tomography (OCT) imaging modality for classification of human oral tissues to detect early dental caries. OCT images of oral tissues with various densities ...

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    9. Influence of the Loci of Non-Cavitated Fissure Caries on Its Detection with Optical Coherence Tomography

      Influence of the Loci of Non-Cavitated Fissure Caries on Its Detection with Optical Coherence Tomography

      Objective The main objective of this study was to evaluate the accuracy of optical coherence tomography (OCT) in detecting naturally occurring non-cavitated fissure caries (NCFC) in totality and at different loci by visually assessing cross-sectional OCT scans (B-scan) with an interpretation criterion. The secondary objective was to evaluate the agreement between dimensions of NCFC measured with OCT and polarized light microscopy (PLM). Methods 71 investigation sites of sound fissure and naturally occurring NCFC on human extracted premolars were identified and scanned with a swept-source OCT. The teeth were then sectioned bucco-lingually at the investigation sites and imaged using PLM. Two ...

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    10. Evaluation of adaptation of ceramic inlays using optical coherence tomography and replica technique

      Evaluation of adaptation of ceramic inlays using optical coherence tomography and replica technique

      Optical coherence tomography (OCT) has generally been used as a nondestructive technique to evaluate integrities of composite restorations. We investigated marginal and internal adaptations of ceramic inlay restorations with OCT and compared them to results with the silicone replica technique. Round-shaped class I cavities were prepared on 16 human maxillary first premolar teeth. Ceramic inlays were fabricated. Silicone replicas from inlays were obtained and sectioned to measure marginal and internal adaptations with a stereomicroscope (Leica Dfc 295, Bensheim, Germany). Inlays were cemented on respective teeth. Marginal and internal adaptations were then measured with the OCT system (Thorlabs, New Jersey, USA ...

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      Mentions: Thorlabs Leica
    11. Detection of carious lesions utilizing depolarization imaging by polarization sensitive optical coherence tomography

      Detection of carious lesions utilizing depolarization imaging by polarization sensitive optical coherence tomography

      As dental caries is one of the most common diseases, the early and noninvasive detection of carious lesions plays an important role in public health care. Optical coherence tomography (OCT) with its ability of depth-resolved, high-resolution, noninvasive, fast imaging has been previously recognized as a promising tool in dentistry. Additionally, polarization sensitive imaging provides quantitative measures on the birefringent tissue properties and can be utilized for imaging dental tissue, especially enamel and dentin. By imaging three exemplary tooth samples ex vivo with proximal white spot, brown spot, and cavity, we show that the combination of polarization sensitive OCT and the ...

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    12. Comparison of microtomography and optical coherence tomography on apical endodontic filling analysis

      Comparison of microtomography and optical coherence tomography on apical endodontic filling analysis

      OBJECTIVES: To compare in vitro differences in the apical filling regarding working length (WL) change and presence of voids and to validate OCT in comparison to µCT for the detection of failures in the apical filling. METHODS: Forty-five uniradicular teeth with round canals, divided into groups (n=15) following the obturation protocols: CL (Lateral condensation), TMC (thermomechanical compaction) and SC (single cone). Samples were scanned using µCT (parameters: 80 kV, 222 µA, and resolution of 11µm), OCT (parameters: SSOCT, 1300nm and axial resolution of 12µm), and periapical digital radiography. The images were analyzed by two blind and calibrated ...

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    13. Resin infiltration analysis into carious lesions by optical coherence tomography

      Resin infiltration analysis into carious lesions by optical coherence tomography

      Purpose/aim: The minimally invasive approach claims for the detection and treatment of early caries lesions. Resin infiltrant materials can penetrate into porosities of the lesion body by capillary forces, preventing the progression of white spot lesions, improving esthetic and providing support to enamel. It is suggested that optical coherence tomography (OCT) could assess penetration depth of the resin infiltrant into white spots lesions, which may provide information about the lesion's progression.

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    14. Feature of the Week 08/17/2017: In Vivo Assessment of Periodontal Structures and Measurement of Gingival Sulcus with Optical Coherence Tomography: A Pilot Study

      Feature of the Week 08/17/2017: 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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    15. Dynamic measurement of the optical properties of bovine enamel demineralization models using four-dimensional optical coherence tomography

      Dynamic measurement of the optical properties of bovine enamel demineralization models using four-dimensional optical coherence tomography

      Dental enamel mineral loss is multifactorial and is consequently explored using a variety of in vitro models. Important factors include the presence of acidic pH and its specific ionic composition, which can both influence lesion characteristics. Optical coherence tomography (OCT) has been demonstrated as a promising tool for studying dental enamel demineralization. However, OCT-based characterization and comparison of demineralization model dynamics are challenging without a consistent experimental environment. Therefore, an automated four-dimensional OCT system was integrated with a multispecimen flow cell to measure and compare the optical properties of subsurface enamel demineralization in different models. This configuration was entirely automated ...

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    16. Quantitative Swept-Source Optical Coherence Tomography of Early Enamel Erosion in vivo

      Quantitative Swept-Source Optical Coherence Tomography of Early Enamel Erosion in vivo

      Swept-source optical coherence tomography (SS-OCT) shows potential for the in vivo quantitative evaluation of micro-structural enamel surface phenomena occurring during early erosive demineralization. This randomized controlled single-blind cross-over clinical study aimed to evaluate the use of SS-OCT for detecting optical changes in the enamel of 30 healthy volunteers subjected to orange juice rinsing (erosive challenge) in comparison to mineral water rinsing (control), according to wiped and non-wiped enamel surface states. Participants were randomly allocated to 60 min of orange juice rinsing (pH 3.8) followed by 60 min of water rinsing (pH 6.7) and vice versa, with a 2-week ...

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    17. Optical coherence tomography applications in tooth wear diagnosis

      Optical coherence tomography applications in tooth wear diagnosis

      Dental wear represents an irreversible loss of dental hard tissue under the action of physical, chemical and mechanical factors, excluding dental caries and acute trauma. Four clinical forms of dental wear are described: erosion, attrition, abfraction, and abrasion. Most experts agree that in each clinical form multiple etiological factors are involved, one being predominant. Optical coherence tomography (OCT) is a noninvasive optical method characterized by a micronic resolution. The applications of this type of investigation are multiple in the medical field in recent years, and OCT is gaining a growing importance in dentistry. The study pointed out through OCT imaging ...

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    18. Radiological and optical coherence tomography aspects in external root resorption

      Radiological and optical coherence tomography aspects in external root resorption

      Pathological external root resorption is a process by which the hard tooth substance is lost because of action of different local irritative or systemic factors. Six forms of external root resorption are described: surface external root resorption, inflammatory external root resorption, replacement external root resorption, invasive external cervical root resorption, ankylosis and transient apical breakdown. The objective of the study was to establish the prevalence of the pathological root resorption in a retrospective radiological study, to highlight radiological aspects of external root resorption and to describe optical coherence tomography (OCT) aspects in pathological root resorption. External root resorption prevalence in ...

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      Mentions: Dan P. Popescu
    19. Effects of Temperature Variations during Sintering of Metal Ceramic Tooth Prostheses Investigated Non-Destructively with Optical Coherence Tomography

      Effects of Temperature Variations during Sintering of Metal Ceramic Tooth Prostheses Investigated Non-Destructively with Optical Coherence Tomography

      Calibration loss of ovens used in sintering metal ceramic prostheses leads to stress and cracks in the material of the prostheses fabricated, and ultimately to failure of the dental treatment. Periodic calibration may not be sufficient to prevent such consequences. Evaluation methods based on firing supplemental control samples are subjective, time-consuming, and rely entirely on the technician’s skills. The aim of this study was to propose an alternative procedure for such evaluations. Fifty prostheses were sintered in a ceramic oven at a temperature lower, equal to or larger than the temperature prescribed by the manufacturer. A non-destructive imaging method ...

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    20. OCT assessment of non-cavitated occlusal carious lesions by variation of incidence angle of probe light and refractive index matching

      OCT assessment of non-cavitated occlusal carious lesions by variation of incidence angle of probe light and refractive index matching

      Objectives This study evaluated (1) the detection and assessment of non-cavitated occlusal carious lesions by spectral domain optical coherence tomography (SD-OCT) and (2) the impact of varying angle of incidence (AI) of probe light and refractive index matching (RIM). Methods Nine extracted human molars with 18 occlusal lesions (ICDAS code 2) were visually selected. 18 regions of interest (ROI) were imaged with SD-OCT under varying AI (0°, ±5°, ±10°, ±15°) and with/without application of glycerine at 0°. X-ray micro computed tomography (μCT) was used as a validation standard. μCT and OCT signals were categorized according to the lesion extent ...

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    21. Automated ablation of dental composite using an IR pulsed laser coupled to a plume emission spectral feedback system

      Automated ablation of dental composite using an IR pulsed laser coupled to a plume emission spectral feedback system

      Objective The purpose of this study is to assemble a laser system for the selective removal of dental composite from tooth surfaces, that is feasible for clinical use incorporating a spectral feedback system, a scanning system, articulating arm and a clinical hand-piece, and evaluate the performance of that system on extracted teeth. Methods Ten extracted teeth were collected and small fillings were placed on the occlusal surface of each tooth. A clinical system featuring a CO 2 laser operating at 50 Hz and spectral optical feedback was used to remove the composite. Removal was confirmed using a cross polarized optical ...

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    22. Dental Applications of Optical Coherence Tomography (OCT) in Cariology

      Dental Applications of Optical Coherence Tomography (OCT) in Cariology

      Across all medical disciplines, therapeutic interventions are based on previously acquired diagnostic information. In cariology, which includes the detection and assessment of the disease “caries” and its lesions, as well as non-invasive to invasive treatment and caries prevention, visual inspection and radiology are routinely used as diagnostic tools. However, the specificity and sensitivity of these standard methods are still unsatisfactory and the detection of defects is often afflicted with a time delay. Numerous novel methods have been developed to improve the unsatisfactory diagnostic possibilities in this specialized medical field. These newer techniques have not yet found widespread acceptance in clinical ...

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    23. 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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    1-24 of 454 1 2 3 4 ... 17 18 19 »
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