1. Articles in category: Dentistry

    1-24 of 442 1 2 3 4 ... 17 18 19 »
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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
    8. 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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    9. 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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    10. 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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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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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    16. 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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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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    22. 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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    23. 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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    24. 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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    1-24 of 442 1 2 3 4 ... 17 18 19 »
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