The importance of a high quality curing light in dentistry
Ivoclar Vivadent’s new Bluephase PowerCure and G4 deliver more than most clinicians expect from a high performance curing light. In addition to the short curing times, starting at just 3 seconds from the Bluephase PowerCure when used with Tetric PowerFill or Tetric PowerFlow, these two lamps support dentists with reliable curing performance, thanks to Polyvision technology integrated, which acts as a personal polymerization assistant. As pointed out by Dr Richard Price, professor of prosthodontics at Dalhousie University Halifax in Nova Scotia, Canada, and expert in intraoral polymerization, the broad emission spectrum of the Bluephase series of lights means that they will polymerize all known dental resins. .
Dr Price, you were instrumental in researching light-curing technologies. Would you mind sharing your thoughts on tradeoffs polymerization and its potential effects on clinical success?
Thank you for this opportunity to discuss the under-polymerization of dental resins. The problem I see is that most dentists have never learned the importance of proper light curing or what to look for in a good curing light. Even the cheapest light and the sloppiest technique will produce a resin restoration that is difficult to touch. The problem is, the dentist cannot determine whether the bottom or the interior of the restoration has been hardened enough. An under-polymerized restoration is weaker and more prone to fractures, bond strength to the tooth is reduced or even non-existent, postoperative sensitivity occurs, resin color stability is compromised, and more chemicals are introduced. released into the body of the partially cured resin. These are all very undesirable results of improper light-curing, and none of them should occur.
What are the key attributes of curing lights for dental professionals?
Curing lights are defined as medical devices, and only approved medical devices should be used on patients. If we look at the curing lights from Ivoclar Vivadent, they are not only approved medical devices, but they are also functional, ergonomic, reliable and rigorously tested to international standards. In addition, the wide emission spectrum of Bluephase lamps means that they will cure all known dental resins and bonding systems.
What key attributes of Bluephase PowerCure will clinicians find useful?
In addition to the new Polyvision technology, the high power and irradiance of light can heal direct and indirect restorations. Depending on the thickness of the indirect restoration, light may light cure the resin cement used to bond most indirect restorations to the tooth. I like to use the high output settings for light-curing the resin under my indirect restorations and the regular output settings for my direct resin restorations.
The patented Polyvision technology has been described as an integrated personal curing assistant. How it works?
The Polyvision feature should help clinicians achieve reliable curing results by automatically detecting unwanted movement of the light tip away from the tooth. When it detects movement, it alerts the operator with vibration or an acoustic signal and automatically increases or stops the curing exposure cycle.
“When it detects movement, it alerts the operator with vibration or an acoustic signal and automatically increases or stops the curing exposure cycle“
Should dentists regularly measure the light output of their curing lights, and is a built-in radiometer useful?
Manufacturers often claim that their light has high irradiance. This can be true, but the power output can be quite low. How can this be? I think the way international standards are written is the cause of a major problem when describing lights. These standards require the manufacturer to measure the total power of the light and then divide that power by the area of the tip of the light. This means that to provide the same illumination, a light with a 7mm diameter light tip only needs to produce half the power of a light with a 10mm diameter light tip (the area of a 7 mm diameter point is half that of a 10 mm point). In addition, this method provides a single irradiance value which is an average value across the tip; however, there are often hot spots of high irradiance and areas where irradiance is rather low through the tip of the light. I see this all the time in the budget lights.
In contrast, the current range of Bluephase lamps offer an exceptionally uniform light output. Some models of Bluephase lamps also include a radiometer in the charging base, and a built-in tester makes it easy to test the light on a daily basis. I know this may seem unnecessary to some, but if you only test your light once a week or once a month, what will you do when the light fails the test because it fails at some point? Will you be recalling and redoing all the restorations you have placed since the last successful test?
Can you please advise on the correct polymerization technique for dental professionals?
When light curing, I recommend the following steps:
- First, read the instructions for using the curing light and the resin you are using. For example, the 3 s exposure time on the Bluephase PowerCure should only be used with Tetric PowerFill and Tetric PowerFlow resins from Ivoclar Vivadent. The 3s exposure mode does not apply to all resins.
- Identify what you want to heal. I know this sounds obvious, but I have often seen the helper hold the curing light over the wrong tooth, at least for part of the exposure time.
- Position the light tip perpendicular to and directly on the restoration, not at an angle. Light travels in a straight line; it does not magically compensate for a slight bad angulation of the point.
- For a direct restoration, start light-curing a few millimeters from the surface as you don’t want to flatten your beautiful anatomy. Then, because the surface will be hard after only 1 second, bring the light tip as close as possible to the restoration and hold it on the restoration. Use both hands if necessary to keep the light tip on the restoration.
- Watch what you’re doing through orange goggles or a shield, and keep the bright tip on the restoration.
- Follow the resin manufacturer’s instructions and light cure for the recommended exposure time.
Do you have any other tips to consider during curing that will help clinicians with their light curing?
For class II situations, I also heal oral and lingual aspects after removing the matrix band. I use the same technique for indirect restorations, but I usually use a tack tip first, wash off excess cement, and then light cure with the tip in contact with the indirect restoration.
Disinfect the lamp using the disinfectant recommended by the manufacturer. Some disinfectants can damage the lumen. Check that the tip of the curing light is clean and has no chips, cracks, or cured resin on it. Using a barrier above the lumen helps control infections and prevents the resins from binding to the lumen. However, extra care should be taken to optimize the operation of Polyvision technology when there is an infection control barrier on the bright tip of the Bluephase PowerCure and G4 lumen. In these cases, the best option is to use both hands and hold the light tip on the restoration and watch what you do with that light tip.
Editorial note: Visit Ivoclar Vivadent‘website for more information on Bluephase PowerCure test.
Dr Price is a Prosthodontist and Director of Digital Dentistry at Dalhousie University in Halifax, Canada. He obtained his BDS from the University of London in England in 1979 and his DDS from the Dalhousie School of Dentistry in 1988. He completed his specialist training at the University of Michigan in 1984 and his doctorate in oral technology and dental materials at the University of Malmö. in Sweden in 2001. He is actively involved in photopolymerization education and dental resin research and is the author of over 190 peer-reviewed papers, and co-author of the chapter on photopolymerization in the 7e edition of the Sturdevant manual, Art and science of operative dentistry.
Dr. Price organizes symposia on light-curing in dentistry. Consensus statements based on these symposia help dentists deliver the best dental restorations to their patients and have been published in English, French, German, Spanish and Portuguese.