508 Improving clinical and laboratory relevance of ISO curing light testing

Saturday, September 7, 2013: 11:30 a.m. - 12:30 p.m.
Location: Limonaia
Presentation Type: Poster Session
C. DEACON1, A.C. SHORTALL2, and C. FELIX1, 1BlueLight analytics inc, Halifax, NS, Canada, 2The Dental School, University of Birmingham, Birmingham, England

Objective: The intended benefit of International Standards Organization (ISO) standards is to ensure that products are “safe, reliable and of good quality”.  ISO 4049 is intended to “standardize the intra-oral and extra-oral energy activation of polymer based restorative materials” and ISO 10650-2 exists to standardize “the requirements and test methods for polymerization activators [light curing units] intended for chair-side use”.  This study examined extra-oral test methods that might be predictive of extra-oral and intra-oral light curing unit (LCU) performance and resulting polymerization activation.

Methods:   An integrating sphere (Labsphere) was used to determine mean (n=3) Radiant Exitance (total power/unit area) at the LCU tip of eight LCUs in their most powerful mode.  Measurements were confirmed using a thermopile (ThorLabs).  The MARC® Resin Calibrator (BlueLight) measured irradiance delivered to an ISO 4049 Depth-of-Cure (ISO-DOC) sized sensor (4 mm diameter) at distances up to 10 mm from the sensor.  Both systems use calibrated spectrometers (Ocean Optics).  The MARC® Resin Calibrator was used to measure the variability in irradiance delivered to an ISO-DOC sized sensor depending on the lateral positioning of the LCU light tip relative to the sensor within a 10 mm diameter (adult molar-sized) circle. 

Results: The results (Table 1) illustrate that the LCU Manufacturer Stated Irradiance is commonly not indicative of the LCU's actual Radiant Exitance, the irradiance delivered to laboratory specimen prepared using ISO-DOC methods, or to clinically simulated scenarios.  As distances between the LCU light tip and sensor increased to 10 mm, variations in irradiance delivered were noted.  Changes in lateral positioning also resulted in significant irradiance differences (P < 0.001), with the highest/lowest values for each LCU expressed as the Lateral Variability Ratio.

Conclusions: Additional test information may strengthen current ISO reporting requirements, better informing scientists and clinicians of the actual extra-oral and intra-oral performance of their LCU.

Table 1

Measurement (units) – Distance from LCU tip

Ivoclar Vivadent

3M ESPE

CMS

SDI

Dentsply

Coltene

Ultradent

Bluephase G2

Bluephase Style

Elipar S10

FlashMax P3 (4 mm Tip)

Radii Plus

SmartLite maX

S.P.E.C.3

VALO

Manufacturer Stated Irradiance (mW/cm²)

1200

1100

1200

4000-5000

1500

1400

3000-3500

3200

Total Radiant Exitance (mW/cm²) at 0 mm

1302

1087

1175

2777

1384

588

3862

2240

ISO-DOC Irradiance (mW/cm²) at 0 mm

1311

1164

2071

2777

1923

1633

6951

3867

ISO-DOC Irradiance (mW/cm²) at 4 mm

1508

1235

1376

1637

814

720

2760

2840

ISO-DOC Irradiance (mW/cm²) at 10 mm

912

444

572

618

192

277

671

1310

ISO-DOC Irradiance Change From 0–10 mm (%)

-30%

-62%

-72%

-78%

-90%

-83%

-90%

-66%

Lateral Variability Ratio at 0 mm

1.3

4.9

1.8

5.9

4.7

2.5

5.0

1.6


Keywords: Composites, Curing lights, Dental materials, Polymerization and Quality assurance
Presenting author's disclosure statement: ** MISSING DISCLOSURE **