An investigation on light intensity variation with composite resin depth in dental curing devices

Abstract

In this thesis whether a new generation LED light source based Light CuringUnit can cure a new generation Dental Restoration Composite in a deep cavitysituation, by a single application, without adverse effects and save time both for the Doctor and the patient, is investigated. An experimental setup, including a made-tospecification LCU using the highest intensity single LED available is prepared to findthe light intensity change through a new generation Dental Composite, from 0 to 8 mm,in 1 mm incrementsIt is observed that the light intensity falls by exponentially in the composite,leaving only 15% of the light entering at the top surface in 4th mm and 5% in the 5thmm. With a given exposure duration of 20s, this proves not enough to polymerize thecomposite at lower levels As the composite polymerizes its opacity decreases to result in an increase in light intensity on the other side of the material by 4%. Thisphenomenon stabilizes in 40s at 1 mm, 72s in 2 mm, 84s in 3 mm. This may be anindication of full polymerization. When longer cure duration of 90s and 180s isapplied composite polymerizes up to a depth of 5.50 mm, while increase in light intensity trend behind 6 mm composite thickness continues (482% increase in 180 s)Results indicate that, if a LCU with enough power to compensate the loss in thematerial is used, it may be possible to cure deep restorations in a single application atshorter total duration.|Keywords: Dental Curing Light, LED, Dental Restoration Composite, Light Intensity Attenuation / Absorption / Penetration, Polymerization.