Dental Curing Lights: Clinical Reality

Quantitative testing of dental composite curing lights improves fracture resistance

Introduction

Light activated resin-based composite fillings have become the standard of care for dental restorations, yet they typically last only six years. Their susceptibility to bulk failure and chipping or marginal fractures is complicated by the variability of the light curing process conducted in the dental chair. Manufacturers recommend minimum exposure intensities and times for their composites to ensure sufficient polymerization, yet these values are often obtained under ideal curing conditions in a laboratory environment.

Experimental Conditions

In reality, there are many clinical variables that affect curing including light source design and performance, distance between the light tip and the composite, access to the area, and operator technique and curing time. Researchers in the dental school at the University of Birmingham, UK, decided to look at differences in the fracture resistance of 10 commercially available composites, contrasting those cured optimally in laboratory conditions to those cured using a clinically relevant energy dosage (quantified in J/cm2). To conduct this research they used two purpose-built instruments called the MARC^® patient simulator (MARC^® PS) and the MARC® resin calibrator (MARC^® RC) from BlueLight Analytics. The MARC^® PS was used to determine a clinically relevant energy dosage and the MARC^® RC was used to enable specific energy dosages to be delivered to the composite specimens prior to fracture resistance testing.