Beam Profiling of Dental Light Curing Units Using Different Camera-Based Systems

Abstract

Objective This study aimed to perform the beam profile of dental light-curing units (LCUs) using mirrorless and smartphone cameras and correlate it to a camera-based laser beam profiling system. Materials and Methods Three LCUs were evaluated (Radii Plus; Bluephase G2; and VALO Cordless). The spectral power of the LCUs was measured by using a spectrophotometer. The light emitted from the LCUs was projected onto a glass diffuser, and the images were recorded by using a mirrorless camera (NEX-F3), a smartphone (iPhone) and a camera-based beam profiler. Bandpass optical-filters were used, and for each LCU, the total spectral power output was integrated to calibrate the images. Statistical analysis was performed by digital image correlation (pixel by pixel) using Pearson’s correlation (α = 0.05; β = 0.2). Results The beam profile images showed nonuniform radiant emittance and spectral emission distributions across all the LCUs light tip. A strong correlation was found among cameras (Pearson’s r = 0.91 ± 0.03 with 95% confidence interval [CI]: 0.88–0.94 for the NEX-F3 and Pearson’s r = 0.88 ± 0.04 with 95% CI: 0.84–0.92 for the iPhone). Conclusion The standard Ophir beam profile system presented the most accurate distribution, but the mirrorless and smartphone cameras presented a strong correlation in the irradiance distribution of the beam profile images. Alternative cameras can be used to perform light beam profile of dental LCUs, but caution is needed as the type of sensor, image bit depth, and image processing are important to obtain accurate results.

The power of light – From dental materials processing to diagnostics and therapeutics

“…Appropriate radiant exposure (the total energy delivered per unit area [J/cm 2 ] given by irradiance [W/ cm 2 ] × exposure time [s]) is required to adequately cure any photocurable polymer-based composite restoration. For these reasons, both the photoinitiator system [12][13][14][15][16][17][18][19][20][21][22][23][24][25] and the dental LCU [6,[26][27][28][29][30][31][32][33][34][35][36] have also been subject to much research and development, particularly with the introduction of new shorter wavelength, more efficient and faster reacting photoinitiators over the last two decades. The diversity in photoinitiator chemistry and light curing technologies has also led to guidelines for proper selection, maintenance and use of LCUs to be published [37][38][39][40].…”

Monowave vs. Polywave Light – Curing Units: Effect on Light Transmission of Composite without Alternative Photoinitiators

“…With polywave LCUs, one of the blue LEDs is usually replaced by the violet LED, which reduces the radiant output in the blue part of the spectrum compared to exclusively blue light LCUs. In addition, the positioning of the violet and blue LEDs can lead to an inhomogeneous spectral output over the irradiated area ( 5 , 17 , 18 ). Since the violet LEDs generally have a lower irradiance, insufficient homogenization of the light output may result in insufficient curing of the parts of the composite restoration illuminated by the predominantly violet light ( 19 , 20 ).…”

Study on laser spot size measurement by scanning-slit method based on back-injection interferometry

“…Beam size is an important attribute of laser because it not only marks the performance of the laser, but also it is involved in the calculation of optical intensity [6][7][8][9]. Optical intensity of laser needs to be provided for laser cutting [10], drilling [11], and remote welding in industry [12] and laser microscopy in biological science [13]. Currently, beam profiler is used to captures, displays, and records the spatial intensity profile of a laser beam at a particular plane transverse to the beam propagation path.…”