7. Time Out: Dental Curing Basics
Q: How well does the average dentist understand the clinical
significance of:
a) Collimation?
b) Under curing the restoration?
c) Pulpal temperature rise?
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9. U-40 Ultracapacitor C.U.R.E Technology
Problem: Is the Restoration Fully Cured?
JADA: 37% of all composite restorations are insufficiently
cured. (Fan et al, April 2002)
CR Reports: “Clinicians must often guess at the time necessary
for adequate polymerization. High-intensity LED lights with
short time settings (1,3 or 5 seconds) imply that fast cure is
possible under ideal conditions, but multiple short exposures
are advised to ensure adequate depth of cure…” (May 2012)
Dr. Gordon Christensen: “Studies regarding the status of the
curing lights used by most general dentists are not impressive.
A study of 214 lights in Toronto showed that the typical curing
lights tested delivered about 512mW/cm2, and about 12% of
the lights tested delivered less than 300mW/cm2.” (Dental
Economics, Sept 2012)
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10. U-40 Ultracapacitor C.U.R.E Technology
Problem: Is the Restoration Fully Cured?
2 mm
LIGHT
CURING
TIP
2 mm
Second composite
increment
2 mm
LIGHT
CURING
TIP
LIGHT
CURING
TIP
2 mm
Second composite
increment
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11. U-40 Ultracapacitor C.U.R.E Technology
Consequences of Under Curing
“…hardness of the surface of the restoration does not indicate adequate
curing of the entire restoration. This situation is of concern, given reports that
inadequate polymerization adversely affects the resin’s physical properties,
reduces bond strength, increases wear and breakdown at the margins,
decreases biocompatibility of the resin restoration and increases bacterial
colonization of the resin in the restoration.”
Seth S, Lee CJ, Ayer CD. Effect of instruction on dental students’ ability to
light cure a simulated restoration. J Can Dent Assoc. 2012;78:c123.
“Restorations are all assumed to start out as equal in properties. A restoration
that is under-cured will have a different set of properties from the rest of the
group. This point cannot be emphasized enough.”
Bayne SC. Correlation of clinical performance with ‘in vitro tests’ of
restorative dental materials that use polymer-based matrices. Dent Mater.
2012;28(1):52-71
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12. U-40 Ultracapacitor C.U.R.E Technology
Components of a Successful Cure
• Characteristics of the restoration and materials
• Operator technique
• Curing light condition
• Deliver energy to fully cure the restoration
• Deliver energy WITHOUT side effects
EFFICIENCY
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13. U-40 Ultracapacitor C.U.R.E Technology
C.U.R.E. Technology:
Curing Uniformity & Reduced Energy
Curing Uniformity
Optimal Light Quality
Reduced Energy = Less Heat
Reduced Energy ≠ Less Output
EFFICIENCY
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14. U-40 Ultracapacitor C.U.R.E Technology
C.U.R.E Technology: Collimation
Source: Georgia Health Sciences University, Rueggeberg FA, May 2013
“This is clinically relevant
because the distance between
the cusp tip and the base of the
interproximal box can often
exceed 7 mm.”
Shortall A, ADA Professional
Product Review. 2013; 8(2): 6-8
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15. U-40 Ultracapacitor C.U.R.E Technology
C.U.R.E. Technology: Distr. of Light
Uniformity as measured by the average perimeter irradiance as a percentage of the 4mm diameter core average
irradiance. Beams not to scale. Source: Georgia Health Sciences University, Rueggeberg FA, May 2013
96.5% 87% 81% 69% 63%
Demi Ultra VALO Bluephase 20i Bluephase Style Elipar S10
Beam Uniformity Comparison: 4mm Core vs. Perimeter
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16. U-40 Ultracapacitor C.U.R.E Technology
C.U.R.E. Technology: Less Heat at Tip
Source: Dental Advisor, R. Yapp, May 2013
Human pain threshold is approximately 112⁰F (Baldissara, 1998)
Amer. Journal of Public Health recommends a max of 120⁰F for hot water to prevent scalding
98.6
112
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17. U-40 Ultracapacitor C.U.R.E Technology
C.U.R.E. Technology: Less Heat at Pulp
Source: Georgia Health Sciences University, Rueggeberg FA, May 2013
On average, the Demi Ultra delivered 10% more power than the other curing lights tested but also
generated 26% less heat on the tooth pulp.
“…the clinician is left wondering which suggested [curing] time is “correct”, and as a result, tends to
over-expose restorations to be on the “safe side”. However, in so doing, the longer exposure results in
generation of more heat within the tooth and surrounding, exposed tissues, leading to possible post-
operative, iatrogenic complications.”
Rueggeberg FA. State-of-the-art: dental photocuring—a review. Dent Mater. 2011;27(1):39-52.
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18. U-40 Ultracapacitor C.U.R.E Technology
C.U.R.E. Technology: Depth of Cure
Depth of Cure measured at 80% conversion (Barcol Hardness)
Lab test results – Kerr recommends 20 seconds to cure 5mm of SonicFill
Source: Dental Advisor, R. Yapp, May 2013
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19. Time Out: C.U.R.E. Technology GTM
Q: What concepts of C.U.R.E. Technology will resonate most
with the average dentist?
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21. Time Out: “Universal” Curing
“A curing light that emits a narrow spectra of light (i.e. blue
visible light only) is not capable of curing all types of resin
based composite materials.”
Q: Do you agree or disagree with this statement?
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22. Why Camphorquinone (CQ)?
CQ is cured by blue light:
• The CQ “sweet spot” is within the blue light
range (460-480 nm)
• The “sweet spot” for TPO and PPD falls into
the violet (400-440 nm) and UV (<400 nm)
wavelength range
UV and “violet” light cannot
penetrate as deeply as blue
light:
• UV and violet light scatter when contacting
the top surface of the restoration
• Blue light passes straight down through the
composite – very little scatters
“The light absorption analysis of dental photo-initiators
showed that CQ exhibited an absorption centered in the
blue region of the light spectrum, with Absmax at 470 nm,
while PPD initiates the curve in the UV region, with Absmax at
398 nm...”
Brandt WC. Effect of different photo-initiators and light
curing units on degree of conversion of composites. Brazil
Oral Res 2010;24(3):263-270.
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23. Misconceptions of “Universal Curing”
Narrow spectrum lights can’t cure all materials…
FALSE!
Source: Kerr Lab Testing, U. Dreschler, Feb 2013Source: Kerr Lab Testing, U. Dreschler, Sept 2013
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24. Misconceptions of “Universal Curing”
Narrow spectrum lights can’t cure all materials.
FALSE according to independent research!!
Brandt WC, Schneider LF, Frollini E, Correr-Sobrinho L, Sinhoreti MA. Effect of different photo-initiators and
light curing units on degree of conversion of composites. Brazil Oral Res 2010;24(3):263-270.
Conclusion:
“The use of LED with a wider emission spectrum did not generate the highest DOC values for the
composite resins used, but the same DOC values.”
www.curingresin.com
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25. Misconceptions of “Universal Curing”
Why is this a misconception?
• The PRIMARY photoinitiator in blended composites is still CQ
• Broad spectrum lights have just ONE lower wavelength LED chip
and it contributes very little power for curing
• Lower wavelength light is not as efficient
• The AMINE does the majority of the work and is NOT light
activated!
26. Misconceptions of “Universal Curing”
Broad spectrum is better…
Not True!
Broad spectrum sacrifices curing power when curing 100% CQ materials
which represent the VAST MAJORITY of composite materials used.
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27. Misconceptions of “Universal Curing”
Why is this a misconception?
• More power delivered in the “sweet spot” for CQ (460-480 nm)
• Power delivered in near UV or “violet” range does very little except add heat
• UV light exists below 400 nm
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28. Summary: When curing RBCs a “focused”
spectrum is…
…and is always more efficient!
About the same and Always better
When curing
blended materials
When curing CQ
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Easy Suite Key Features – a set of product features that improve ease of operation and maintenance, allowing the dental practicioner to focus less on the curing light and more on the patient.
Blue (light)and yellow (photoinitiator) are complimentary colors.
Polymerization process:Light activates the CQ photoinitiatorCQ photoinitiator interacts with the amine co-initiator to polymerize the materialCQ cannot do the job alone – it needs to interact with the amineOther photoinitiators (TPO, PPD) do not need the amine, but the light that activates them scatters and cannot penetrate deep into the material
Of these considerations, what has no relationship with the curing light?Opacity (material)Type and depth of restoration (patient anatomy)Positioning of tip (user)Distance of tip (user/patient anatomy)The rest all are impacted by the curing light and it’s properties!CollimationUniformity of beam (both output AND wavelength)Output of lightHeat generationWavelength of beam
Notes:In order to make PPD and TPO/Lucerine as efficient as CQ it would take A LOT of UV and near UV light, which could compromise the safety of the patient.CQ is yellow in color in its RAW form, but is bleached during the curing process and therefore has no impact on color stability. It is also used in very small quantities – on the order of 0.4% by weight or less.
Image 1: The top surface of the restoration facing the curing light tip gets blasted with energy and cures easily. This is the surface the dentists measures to gauge if the restoration is fully cured. But what about the BOTTOM surface?Image 2: A restoration is NOT like a steak. You can flip the steak over and cook it on both sides. What happens when you try to cook a steak on one side?We are pushing the outer envelope of curing: Several curing lights on the market have super high outputs and claim curing in under three seconds, and bulk fills are increasing the depth of curing. But is the bottom really getting cured? And if you do multiple cures what is the impact on the tooth pulp?Image 3: The Coltene SPEC-3 claims curing of 2mm in just 1 second in 3K mode! (3,000 mW/cm2)Image 4: Bulk fill materials represent the largest growing segment of the composite market
C.U.R.E. Technology is a series of features that work together to reduce heat, provide a uniform depth of cure and overall to improve curing efficiency and efficacy. There are THREE main principles:Curing Uniformity requires Optimal Light Quality – Collimation and Uniformity of Beam (output AND wavelength)Reduced Energy equates to Less Heat, or Less Heat Generation Reduced Energy is NOT equal to less output – this is NOT basic physics! Demi Ultra can create the same high Output of Light as the Demi plus with HALF the energy.
Collimation is a strength of the Elipar S10. They stress the importance of curing power at the clinically relevant distance of 7mm.These results show that Demi Ultra is equivalent to Elipar in terms of collimation and better than the VALO and Bluephase lights.
Another BBQ analogy – if you don’t spread the coals out all the heat is in the center and the meat doesn’t fully cook around the perimeter. When curing, if there isn’t enough power to fully cure the margins then the restoration may fail.The image showing curing area comes straight from 3M’s ad for Elipar. Their claim is a 10mm tip can cure the restoration in one cure, while a smaller tip needs two cures to cover the same area. However, the full 10mm area of there tip is not uniform – the outer perimeter receives 37% LESS energy than the core. Is it enough to energy to fully cure the margins?
Notes:VALO in XTRA power mode yielded almost 124⁰F for only 3 x 3-sec curing cycles, including a 3 second delay between.Tests of the VALO in High power mode and the Bluephase 20i in Turbo mode also included a 3 second delay between multiple curing cycles.Baldissara study regarding human pain threshold is subjective – each person is differentInformation about scalding water on skin is included as a reference – gingival tissues likely more sensitive to heat than skinPatients are usually numb and may be unaware of injury until after procedure
Output measurements for each light were obtained by Dr Rueggeberg as part of the irradiance study of the Demi ultra and competitor curing lights. The actual output values were used instead of the manufacturer’s advertised output. Note that they are all quite different. The Demi Ultra’s output measurement is 4 mW/cm2 more than the advertised average with PLS activated.“The clinician is left wondering which suggested [curing] time is “correct”, and as a result, tends to over-expose restorations to be on the “safe side”. However, in so doing, the longer exposure results in generation of more heat within the tooth and surrounding, exposed tissues, leading to possible post-operative, iatrogenic complications.”Rueggeberg FA. State-of-the-art: dental photocuring—a review.Dent Mater. 2011;27(1):39-52.
Notes:Demi Ultra and Elipar S10 showed equivalent resultsVALO and 20i were tested in default modes (standard and high respectively)NONE of the tests yielded adequate conversion (above 80%). This simulation shows the importance of tip distance and how it can impact the depth of cure and the required curing time to achieve an adequate DOC - particularly the bottom layer that is closer to the pulp.
Notes:In order to make PPD and TPO/Lucerine as efficient as CQ it would take A LOT of UV and near UV light, which could compromise the safety of the patient.CQ is yellow in color in its RAW form, but is bleached during the curing process and therefore has no impact on color stability. It is also used in very small quantities – on the order of 0.4% by weight or less.
Notes:In order to make PPD and TPO/Lucerine as efficient as CQ it would take A LOT of UV and near UV light, which could compromise the safety of the patient.CQ is yellow in color in its RAW form, but is bleached during the curing process and therefore has no impact on color stability. It is also used in very small quantities – on the order of 0.4% by weight or less.
Notes:In order to make PPD and TPO/Lucerine as efficient as CQ it would take A LOT of UV and near UV light, which could compromise the safety of the patient.CQ is yellow in color in its RAW form, but is bleached during the curing process and therefore has no impact on color stability. It is also used in very small quantities – on the order of 0.4% by weight or less.
The lights used in this study were:Narrow – UltraBlue, DMC EquipmentBroad – UltraLume, UltradentThe study compared the lights in terms of J/cm2 (flux), which is a function of time, to compensate for the difference in outputs (mW/cm2).The percentages are DC, or degree of conversion, not Depth of cure (DOC) hardness
Notes:Images are from Ultradent and Ivoclar’s websites and show how poorly the light is blended due to adding a third/fourth LED at a lower power and wavelength.
Notes:Demi Ultra and Elipar S10 have narrow “blue only” light spectrums targeting the “sweet spot” of CQ (460-480 nm)VALO and Bluephase 20i have broad light spectrums bordering on the UV range.The material (SonicFill) represents the vast majority of materials used because it is 100% CQDemi Ultra and Elipar S10 deliver a HIGHER DOC value while delivering 36% LESS POWER on average compared to the broad spectrum lights.
Notes:More power delivered – the red line is taller in the area between 450nm and 480 nm, indicating that the Demi Ultra is delivering more power in the “sweet spot” to cure CQ compared to Bluephase Style and VALOLower wavelength light (purple range) is outside the primary absorption spectrum of CQ and therefore contribute very little or no energy to curingUV and near UV light (purple) still contribute to heat generation even though they have very little impact on curing
Notes:Images are from Ultradent and Ivoclar’s websites and show how poorly the light is blended due to adding a third/fourth LED at a lower power and wavelength.