FACT OR FOLLY? All light curing units are created equally. Summary of the Dalhousie University’s First Conference on Light Curing
The conferences on Light Sources in Dentistry held at Dalhousie University, Halifax, NS bring world experts from academia and industry together to discuss ideas, advances and issues related to resin-based composite materials and light sources used in dentistry.
The 2nd Halifax Conference took place this past spring and information from this meeting has now been published. (Consensus statement from May Light Sources Meeting published in Journal of Adhesive Dentistry Vol. 16, No 4, 2014: Light Curing – Guidelines for Practitioners)
Short summaries of the topics covered at the 1st Halifax Conference (held in October 2012) along with links to the YouTube videos by various Key Opinion Leaders are listed below.
Intensity of QTH curing Lights in dental offices around the world
Dr. O. El-Mowafy
Take Home Message
Every research publication from around the world has shown that a vast number of lights in dental offices emit sub-optimal amounts of light. As age of the light unit increases, the light output decreases. Regular monitoring of curing lights is required.
Demonstrating the effect of operator technique on energy delivered to a restoration
Dr. R. Price
Take Home Message
When appropriate operator techniques are used during light curing, the amount of energy delivered to a restoration can more than double. The MARCTM System was developed to help clinicians (dentists, assistants as well as students) optimize their light curing techniques.
Effect of Moving the Curing Light on Energy Delivered to a Restoration
Dr. R. Price
Take Home Message
Ideally, when curing a resin composite material, the light should be held as close to the resin surface as possible (without touching) and at 90° to the restoration’s surface. Any movement of the light source can result in a decrease in the amount of energy delivered to the restoration. This can adversely affect the quality of the cure and the properties of the resin.
Effects of High Irradiance on Curing Rate and Stress Generation in Dental Composites
Dr. J. Ferracane
Take Home Message
When resin composites are placed in a tooth and light cured, a “tug-of-war” occurs between the resin composite and the tooth walls as polymerization shrinkage takes place. Contraction stress rates can be reduced by:
- ↑inhibitor concentration
- modifying initiators in materials
- ↓irradiance delivered to materials and ↑ exposure time
- ↓curing rate – pulse delay mode (soft start)
Teaching Effective Light Curing
Drs. S. Armstrong & M. Vargas
Take Home Message
The University of Iowa has undergone a paradigm shift when it comes to teaching light curing. Students are trained on the MARCTM Patient Simulator which measures the irradiance received by simulated restorations and calculates the amount of time required to completely cure various materials they are using.
What to Look for When Choosing a New Curing Light
Dr. A. Shortall
https://www.youtube.com/watch?v=7pNi0KOFltE
Take Home Message
Currently, there are several different light curing options available on the market. Dentists should be aware of the effects that exposure time and distance from the light tip have on the irradiance and energy received by the restoration.