Figure 1
Chemical structure of a methacrylate-based monomer.
Figure 2
Schematic illustration of external energy factors acting on a radical-generating species to result in formation of “free radicals”.
Figure 3
Diagram of the polymerization initiation step.
Figure 4
Polymer chain propagation by addition of successive monomer units.
Figure 5
Diagram of chain termination via monomer-radical collision.
Figure 6
Electromagnetic spectrum with correlated depictions of trends in frequency and wavelength, as well as energy content and location of commonly used band portions.
Figure 7
Correlation of wavelength (in nanometers) and human perception of color, as well as perspective of the physical wavelength of violet light.
Figure 8
Visible light absorption spectrum of camphorquinone, ranging from about 425 to 495 nm.
Figure 9
Visible light absorption of the photoinitiator, Lucirin® TPO, spanning from about 390 to 410 nm.
Figure 10
Visible light absorption of PPD, ranging between 390 to 460 nm.
Figure 11
Visible light absorption of Ivocerin® is seen to span from about 390 to 445 nm.
Figure 12
Differences in spectral absorption profiles and absolute absorption values among the dental photoinitiators, when present at similar molar concentrations.
Figure 13
Internal components of a typical QTH curing light.
Figure 14
Different styles of removable fiberoptic light guides used in QTH lights.
Figure 15
Spectral emission profile of a typical QTH light with absorption wavelength ranges for typical dental photoinitiators.
Figure 16
PAC light with associated heat sinking apparatus.
Figure 17
Panel of early PAC light showing options for 1, 2, or 3-second lone exposures.
Figure 18
430 and 460 nm tips used in early PAC lights.
Figure 19
Spectral emission profile of a typical PAC light with absorption wavelength ranges for typical photoinitiators.
Figure 20
Argon-ion dental light-curing laser.
Figure 21
Spectral emission profile of an argon-ion laser curing light with absorption wavelength ranges for typical dental photoinitiators.
Figure 22
Example of a turbo-tip light guide used to increase irradiance values from lower-powered curing lights.
Figure 23
Individual LED can-type emitters closely packed into an array of a first-generation dental LED curing light.
Figure 24
Small footprint area chips used in later versions of 1st generation, blue dental light curing units.
Figure 25
Spectral emission profile of an early, 1st generation blue LED dental curing light
Figure 26
Second generation blue LED chip array, shown in the powered-off (A) and powered-on (B) modes.
Figure 27
Spectral emission from a typical second generation, blue LED curing light.
Figure 28
Image of the construction of the emitting elements in Ultradent’s Ultralume 5 curing light
Figure 29
Image of the construction of the emitting elements in Ivoclar’s Bluephase STYLE curing light.
Figure 30
Image of the construction of the emitting elements of a 4 element combination LED array: only the lower left chip emits violet light – the others emit blue light.
Figure 31
Image of the construction of the emitting elements in Ultradent’s VALO curing light: (a) chips off (B) chips on.
Figure 32
Spectral emission profile of the VALO curing light.
Figure 33
Spectral emission profile of a typical 3rd generation dental LED curing light
Figure 34
A variety of form factors of LED curing lights.
Figure 35
Power (mW) versus tip-to-target distance (mm) graph showing how the distances affect the irradiance delivered by three curing lights.
Figure 36
Light beam uniformity from two curing lights, one with a uniform light output (top figures) and one with a “hot spots” of very bright light and “cold spots” (bottom figures).
Figure 37
Clinical scenarios showing that some lights may not cover the entire restoration.
Figure 38
Maximum hazard versus wavelength (nm) graph for single peak (A) and broadband LED light-curing units.
Figure 39
Evaluation of the curing light’s status with radiometer.
Light curing in dentistry and clinical implications: a literature review
