22 Jun 2018

What makes an ideal light?

A curing light is designed for curing resin rapidly. It is important to choose an ideal light which can cure resin properly, otherwise the inadequate polymerization would lead to clinical failures and decrease patient comfort.

When you select a curing light, there are many factors that you would consider. Does the curing light have a board emission spectrum? Does the unit have sufficient light intensity and collimated beam? How big is the curing footprint? Is it durable? And is it easy to access to patient’s mouth without sacrificing patient comfort? To assist you to choose the right curing light, we will discuss 7 most important features which will make an ideal light.

Power density

Power density also called light intensity, which is measured by power output, or expressed as mW/cm². To cure a 1.5 – 2mm thick resin composite, a minimum irradiance of 400 mW/cm² is required from a curing light while 1,000 mW/cm² is considered to be ideal. Inadequate light intensity cannot lead to adequate depth of cure but would increase bacterial colonization and reduce bond strength, etc.

Beam collimation

With all curing lights, the beam disperses when it exits the light guide or tip, resulting in lost power density. With many lights, this power reduction causes ineffective curing, which can lead to microleakage, sensitivity, and restoration failures. To maximize a light’s efficacy at normal working distances, the beam must be collimated to allow optimal energy to reach the restoration in all cases.

Spectral distribution

This refers to power delivered over specific wavelengths or bands of colours in the light, e.g. 370 – 510 nm. If a curing light does not emit light over a broad spectrum, some dental materials will not polymerize. A true broad‐spectrum curing light needs to produce light in the right colour ranges—where the photo initiators are most active—to thoroughly cure dental materials.

Easy access

The average adult male mouth opens a maximum of 55mm from incisal edge to incisal edge. That doesn’t leave much room to work, especially in the posterior region. There are many gun-style or modified gun‐style curing lights with bulky light guides or heads in the market. These curing lights become problematic if they feature the usual 45° angle bend, which makes it nearly impossible to properly position the light for adequate curing, as patients simply cannot open their mouths wide enough. An ideal curing light must allow the clinician to properly position the curing light in all areas of the mouth, without discomfort to the patient.

Curing footprint

The surface space that occupied with the curing light is called the curing footprint. A narrow light tip emits a small footprint. It is beneficial to have a curing light with a larger footprint which can cover a larger restoration surface. It is time saving for dental professionals as they don’t need to cure multiple times in large restorations. 


A curing light is an essential part of the office. The product should be robust and not break when dropped. A durable curing light is tough enough to withstand all types of handling in the office and durable enough to meet your clinical expectations day in and day out.


It is essential to have your curing light covered by warranty. The longer warranty the curing light has, the better value you can get out of your device. A better quality curing light should have a 3 year warranty. The manufacturer should warrant the product for a period of 3 years from the date of purchase, conform in all materials respects to the specifications as set forth in manufacturer’s documentation accompanying the product, and be free from any defects in materials and/or workmanship. This type of service can maintain your curing light in the best condition and ensure it can deliver the right power.

In summary, when purchasing a curing light, the key considerations are the light intensity, the beam collimation, the spectral distribution, the accessibility, the curing footprint it has, the durability of the curing light, and the warranty that the manufacturer offers. As we all use our curing lights in a daily basis, without a good quality curing light, we could not deliver a successful restoration. We hope the features that have been discussed can give you some ideas about how to choose the right curing light for your practice.











Recent Posts