Demi ultra rt deck may 2014 under curing and cure technology

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D e n t a l C u r i n g

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The Light Spectrum

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Photoinitiators

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http://www.ncbi.nlm.nih.gov/pubmed/17804051

CQ Photo-initiator

Amine

P O L Y M E R I Z A T I O N

Ratio of AMINE to CQ Photoinitiator is usually 2:1Amine is a CO-INITIATOR and is NOT light activated

Curing Light

The Polymerization Process

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U-40 Ultracapacitor C.U.R.E Technology

Curing Considerations

Position of TipDistribution of Light/Energy

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Time Out: Dental Curing BasicsQ: 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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C . U . R . E . T e c h n o l o g y

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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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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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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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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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C.U.R.E. Technology: Curing Uniformity & Reduced Energy

Curing UniformityOptimal Light Quality

Reduced Energy = Less Heat

Reduced Energy ≠ Less Output

EFFICIENCY

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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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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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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

98.6112

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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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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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Time Out: C.U.R.E. Technology GTMQ: What concepts of C.U.R.E. Technology will resonate most with the average dentist?

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U n i v e r s a l C u r i n g

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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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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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Misconceptions of “Universal Curing”Narrow spectrum lights can’t cure all materials…FALSE!

Source: Kerr Lab Testing, U. Dreschler, Feb 2013 Source: Kerr Lab Testing, U. Dreschler, Sept 2013

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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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http://www.curingresin.com/

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!

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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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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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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T h a n k Y o u

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