Evaluation of in vitro dental restoration by optical coherence tomography
Carregando...
Data
Data de publicação
2005
Orientador
Título da Revista
ISSN da Revista
Título do Volume
É parte de
É parte de
É parte de
É parte de
CONFERENCE ON LASER AND ELECTROOPTICS IN EUROPE
Exportar
Resumo
Optical coherence tomography (OCT) is a well established interferometric technique that performs high resolution,
non-invasive, cross-sectional tomographic imaging of tissue microstructures and other biophotonics applications [1]. In
Odontology, a series of reports first appeared in 1998 [2], with imaging of both hard and soft oral tissues. This led to
several diagnostics of bucal diseases, including'periodontal, early caries, among others. Dental caries is known as a
multifactorial pathological process, characterized by hard tissue demineralization. Early diagnostics is thus desired. In
this communication, we report the application of OCT to dental restoration evaluation, particularly analyzing failure
gaps left after the restoration has been performed. Imaging resolution of 10-15 fun have been achieved and > 50 µm
dental cavities are measured. Molar dental restorations on enamel of extracted teeth were performed using composite
resin and amalgam as the restoring material. Failure gaps were set by using a 50 µm thick acetate tape during the
restoration procedure. The results from the OCT were compared to two-dimensional images obtained with x-ray and
optical microscope.
The basic experimental scheme for the OCT is similar to most set ups reported in the literature [ 1,2]. Femtosecond
pulses, operating at 800 nm, were used to induce a spectral broadening in a nonlinear fiber. The initial spectral width of
1Onm, were broadened to 41nm providing a depth spatial resolution of 10µm. The output light from the nonlinear fiber
was directed to a 2X2 fiber coupler (50/50 @800nm) that composed the Michelson Interferometer. Both arms (the
reference and sample) were set on computer controlled translation stages with 200nm minimum displacement steps. The
collimated beam incident on the sample was focused using a 10cm focal distance length, providing a lateral resolution
of 25µm. The collected light on the output port of the Michelson Interferometer was sent to a highly sensitive
photodetector, whose output was electronically filtered according to the translation stages speed. A and B scans were
obtained for several samples. Samples of extracted molar human teeth (available at the University bank tooth) were
sectioned and restored with amalgam and composite resin, and failure gaps were purposely introduced in selected
regions of the tooth enamel using 50µm thick acetate sheets. Figure 1 shows a summary of the A and B scan results,
displaying the interferometric backscattered amplitude as a function of axial position and lateral displacement along the
gap. Left figure shows a trace where there is no gap purposely left, and the enamel-restoration interface is seen, while
right figure shows a purposely left failure gap using the 50µm acetate sheet on an amalgam restoration. The gap is
clearly detected, and is wider than the acetate sheet due to natural imperfections in placing the acetate. From our data, a
2D plot has been constructed. The results were compared to radiographic images, showing the potential of the technique
for detection of earlier caries, since X-Ray can not show the gap failure, only depicting the restored region. OCT has the
advantage of showing the restored region as well as the gap, if existing, localizing precisely its position.
Como referenciar
MELO, L.S.A. de; CARVALHO, M.T. de; GOMES, A.S.L.; ARAUJO, RENATO E. de; FREITAS, A.Z.; ZEZELL, D.; VIEIRA JUNIOR, N.D. Evaluation of in vitro dental restoration by optical coherence tomography. In: CONFERENCE ON LASER AND ELECTROOPTICS IN EUROPE, Munich. Abstract... DOI: 10.1109/CLEOE.2005.1568418. Disponível em: http://repositorio.ipen.br/handle/123456789/19975. Acesso em: 20 Mar 2026.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.