Category: Dentistry

Objective Conventional diagnostic methods frequently detect only late stage enamel demineralization under composite resin restorations. The objective of this study is to examine the subsurface tooth–composite interface and to assess for the presence of secondary caries in pediatric patients using a novel Optical Coherence Tomography System with an intraoral probe. Methods A newly designed intraoral cross polarization swept source optical coherence tomography (CP-OCT) imaging system was used to examine the integrity of the enamel–composite interfaces in vivo. Twenty-two pediatric subjects were recruited with either recently placed or long standing composite restorations in their primary teeth. To better understand ...

The diagnosis of dental caries at an early stage enables the implementation of conservative treatments based on dental preservation. Several diagnostic methods have been developed, like visual-tactile and radiographic are the most commons but are limited for this application. The Optical Coherence Tomography is a technique that provides information of optical properties of enamel, which may change due to the decay process. The objective of this study was to evaluate the ability of OCT to detect different stages of demineralization of tooth enamel during the development of artificial caries lesions, taking as a reference standard for comparison sectional microhardness testing ...

Establishing reproducible methodologies for assessment of early enamel lesions using optical coherence tomography (OCT) appears to be challenging. This in vitro study longitudinally evaluated the subsurface enamel lesion progression after 3, 9 and 15 days by cross-sectional scanning using 1310 nm centered swept-source OCT (SS-OCT) under hydrated and dry conditions. The positive difference between the depth-integrated OCT signals at dry and hydrated conditions were calculated and adopted as dehydration parameter (DH). A linear regression was found between DH and the square root of demineralization time (R2 = 0.99). Significant differences were found in DH between sound and demineralized enamel, and ...

A cross-polarization 1310-nm optical coherence tomography system (CP-OCT), using a beam splitter based design, was used to assess ex vivo growth of complex multi-species dental biofilms. These biofilm microcosms were derived from plaque samples along the interface of composite or amalgam restoration in children with a history of early childhood caries. This paper presents a method of measuring the mean biofilm height of mature biofilms using CP-OCT. For our in vivo application, the novel swept source based CP-OCT intraoral probe (Santec Co. Komaki, Japan) dimensions and system image acquisition speed (20 image frames/second) allowed imaging pediatric subjects as young ...

Objectives It is difficult to completely remineralize carious lesions because diffusion into the interior of the lesion is inhibited as new mineral is deposited in the outermost layers. In previous remineralization studies employing polarization sensitive optical coherence tomography (PS-OCT), two models of remineralization were employed and in both models there was preferential deposition of mineral in the outer most layer. In this study we attempted to remineralize the entire lesion using an acidic remineralization model and demonstrate that this remineralization can be monitored using PS-OCT. Methods Artificial lesions approximately 100–150μm in-depth were exposed to an acidic remineralization regimen and ...

In this paper, we propose a highly nonlinear dispersion flattened hexagonal photonic crystal fiber (HNDF-HPCF) with nonlinear coefficients as large as 57.5W−1 km−1 at 1.31 μm wavelength for dental optical coherence tomography (OCT) applications. This HNDF-HPCF offers not only large nonlinear coefficient but also very flat dispersion slope and very low confinement losses. Using these characteristics of our proposed PCF, it is shown through simulations by using finite difference method with an anisotropic perfectly matched boundary layer that this PCF offers the efficient supercontinuum (SC) generation for dental OCT applications at 1.31 μm wavelength using ...

Abstract Aims:  Quantifying the ex vivo growth of complex multi-species dental biofilms by cross-polarization 1310-nm optical coherence tomography system (CP-OCT) was investigated. Methods and Results:  Bacterial microcosms, which were derived from plaque samples of pediatric subjects, were incubated in a biofilm reactor system containing discs of different dental materials for 72 hours with daily sucrose pulsing (5x). CP-OCT analysis of biofilm mass was validated with crystal violet assays at various growth stages of these complex biofilms. CP-OCT was able to filter out the back-reflected signals of water layers in the hydrated biofilm and allowed for direct biofilm quantification. The overall ...

Aim:  To investigate the ability of swept-source optical coherence tomography (SS-OCT) to detect incomplete crown fractures (cracks) in extracted teeth. Methodology:  Cracks were created by subjecting 30 porcine premolars to impaction by a steel rod plunging from the occlusal tip. SS-OCT images and stereomicroscopic photographs of the surface were acquired for each specimen before and after impaction. For evaluation, the focused light beam of SS-OCT was projected from 3 directions on the same plane: buccal or lingual, 45° to the mesial, and 45° to the distal. Histological sections were prepared after impaction, and length and width of cracks and lamellae ...

Objectives:  For decades there has been increasing focus on the development of clinically acceptable, more sensitive and specific methods for the accurate and non-invasive diagnosis and prognosis of periodontitis. There are several well-known inherent drawbacks to current clinical procedures. The purpose of this article is to summarise some of the newly emerging diagnostic approaches, namely: the ultrasonographic probe; cone-beam computed tomography; optical coherence tomography; optical spectroscopy, and proteome analysis. Results:  These novel diagnostic tools complement one another and, together with conventional clinical and radiographic examination, are likely to provide more accurate methods of diagnosing periodontitis. However, these techniques are yet ...

Objectives To investigate optical properties of human enamel and dentine in relationship to structural orientation of enamel prisms and dentinal tubules by optical coherence tomography (OCT). Methods Discs of 300–400 μm thickness including enamel with cross-cut or long-cut prisms and mid-coronal dentine with cross-cut, long-cut or oblique-cut tubules were obtained from 28 non-carious freshly extracted human third molars sectioned at different directions. Each disc was placed over a metal plate and B-scan images were obtained by a swept-source OCT at 1330 nm centre wavelength (Dental SS-OCT Prototype 1, Panasonic Healthcare Co., Ltd, Japan). Refractive index (n) calculated from optical ...

A cross-polarization 1310-nm optical coherence tomography system (CP-OCT), using a beam splitter based design, was used to assess ex vivo growth of complex multi-species dental biofilms. These biofilm microcosms were derived from plaque samples along the interface of composite or amalgam restoration in children with a history of early childhood caries. This paper presents a method of measuring the mean biofilm height of mature biofilms using CP-OCT. For our in vivo application, the novel swept source based CP-OCT intraoral probe (Santec Co. Komaki, Japan) dimensions and system image acquisition speed (20 image frames/second) allowed imaging pediatric subjects as young ...

Frequent monitoring of gingival sulcus will provide valuable information for judging the presence and severity of periodontal disease. Optical coherence tomography, as a 3D high resolution high speed imaging modality is able to provide information for pocket depth, gum contour, gum texture, gum recession simultaneously. A handheld forward-viewing miniature resonant fiber-scanning probe was developed for in-vivo gingival sulcus imaging. The fiber cantilever driven by magnetic force vibrates at resonant frequency. A synchronized linear phase-modulation was applied in the reference arm by the galvanometer-driven reference mirror. Full-range, complex-conjugate-free, real-time endoscopic SD-OCT was achieved by accelerating the data process using graphics processing ...

We previously demonstrated that a swept-source optical coherence tomography system (SS-OCT) without polarization-sensing could quantitatively estimate the progress of cavitated dentin lesions in vitro. The purpose of the current study was to investigate the ability to estimate the lesion development in non-cavitated dentin lesions with a surface layer. Bovine root dentin specimens were subjected to different periods of demineralization (1 to 14 days). Cross-sectional images of the specimens before and after the demineralization were captured by SS-OCT at 1310 nm center wavelength. Following each period, the specimens were cut into sections for transverse microradiography (TMR) and correlations between SS-OCT data ...

The aim of this work was to investigate relationship between refractive index (n) and mineral content (MC) (vol %) of enamel and dentin using swept-source optical coherence tomography (SS-OCT) and transverse microradiography (TMR). Enamel and dentin blocks were partitioned into three regions. The middle partition of each sample was covered with a nail polish to protect the sound area during exposure to the treatment solutions. Samples were demineralized in a demineralizing solution, which was refreshed once a week, for 2 months. One window was covered with acid-resistant varnish, leaving the other window exposed; the samples were placed in a solution for ...

Selecting the most representative site for biopsy is crucial in establishing a definitive diagnosis of oral epithelial dysplasia. The current process involves clinical examination that can be subjective and prone to sampling errors. The aim of this study was therefore to investigate the use of optical coherence tomography (OCT) for differentiation of normal and dysplastic oral epithelial samples, with a view to developing an objective and reproducible approach for biopsy site selection. Biopsy samples from patients with fibro-epithelial polyps (n = 13), mild dysplasia (n = 2), and moderate/severe dysplasia (n = 4) were scanned at 5-μm intervals using an OCT microscope ...