Up Your Bioactivity With Proper Curing Tools

Most clinicians blame “sensitive composites” on bonding steps or patient factors, but we keep coming back to a simpler culprit: the cure. Dr. Michael Miyasaki walks us through how incomplete polymerization and polymerization shrinkage can create stress, gaps, and long-term restorative problems, even when the restoration looks fine on top. If you’ve ever wondered why a Class I or Class II composite feels great chairside and then comes back with postoperative sensitivity, this conversation gets specific about what to change.

We talk about the two big ways curing goes wrong: not delivering enough energy to fully cure the material, and shadowing that blocks light from reaching key walls and the gingival floor. We explain why keeping the curing light close matters, how light guide shape affects access to posterior teeth, and why beam collimation can be the difference between a confident cure and a guess. We also dig into modern photoinitiators and quad-wave wavelength technology, and how improved curing can reduce shrinkage, strengthen margins, cut marginal staining, and lower the risk of secondary decay.

Then we get hands-on with tools and techniques you can use right away: a transillumination diagnostic tip to help visualize cracks, a tight contact curing ball approach to reduce open contacts and food impaction in Class II restorations, and a small tacking tip workflow for crown cementation and veneers that stabilizes the restoration so cleanup and flossing are faster before the final cure. If you want restorations you can trust, start by upgrading your curing fundamentals.

Subscribe, share this with a colleague who fights sensitivity and open contacts, and leave a review with the curing light and curing time you’re using so we can compare notes.

Transcript

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Why Materials And Tools Matter

SPEAKER_00 0:18

Hi, I'm Dr. Michael Miyasaki, and thank you for joining this program, which is titled How to Up Your Bioactivity Game with the Correct Materials and Tools. So we've been talking about why we use the regen material. But what I want to do is we're leading up to how you actually place restorations using the regen. But to be clear, we have to understand some of the materials and tools we're going to use so it all makes

The Real Causes Of Sensitivity

SPEAKER_00 0:42

sense. So that's what I'm going to dig in today. Now, one of the things that we deal with when we're placing a direct restoration is sensitivity issues. Two of the most common reasons why we get sensitivity is one, when we cure our composite material material, our light-cured composite material, we don't provide enough energy to actually completely cure it. Or maybe we cure the top, but we don't cure all the way to the bottom. Or maybe while the material is curing, it actually pulls away from our tooth preparation walls because of shrinkage. Now, there's some tips that I always tell everybody to follow when you're curing composite. One is to keep your composite curing light close to the tooth. Don't hold it away from the tooth, get as close as you can, because we know that the intensity of that light energy diminishes the further away that it is from the material. And one of the areas that we really want to get down to is that gingival floor. So I need to make sure with most curing lights that I'm really almost touching the tooth, if not touching the tooth. We need to get that energy down.

Distance And Shadowing Kill Your Cure

SPEAKER_00 1:53

Now, when the energy is applied to the tooth, the second thing I have to think about is shadowing. And what shadowing means is that depending on the shape of the light guide, we may not be able to get our curing energy right over the tooth. In order to adapt the positioning because the patient can't open sufficiently or the tooth is so far back, or maybe it's just the angulation of adjacent teeth, that what happens is we can create shadowing. And if we're using a light cured material, even our adhesive, when we get the shadowing, as you see on these bottom photos, those areas of our adhesive, our composite, are not curing. That can lead to issues further down the road. So in the top two photos, you can see all the walls basically are being hit by the light. On the bottom, you can see there's a lot of walls that are in the shadows. So we need to have a light that and a light guide that helps us get back to the T so we don't have those issues. On the left-hand side, you see we have a very low profile light guide. And because it's slow, so low profile, we can go all the way back, even to a second or third molar, come in low over the occlusal surfaces of the T so the patient doesn't have to crank the jaw open. And yet, because we're emitting that light at about a 90-degree angle, all that light energy is hitting all the walls of that molar preparation. Whereas on the right hand side, this is a light guide designed more for a curing light that's used more for the anterior curing of teeth. So you don't have to reach way back there. But when you're trying to use that type of light guide to get to a posterior tooth, what you often find is you have to bring the light guide in at an angle. And so we get that shadowing that I showed you in the previous slide. Issues. Because whether it be our adhesive that's light cured or a composite, there can be an area that doesn't cure well.

Choosing A High-Quality Curing Light

SPEAKER_00 3:45

So one of the tools that I really depend on is the pink wave curing light. Now think about it. Every day we are curing materials, and we're trusting that that material is hardening up with our curing light. But if I were to put a hundred dentists in a room and ask you what light you're using, there's a myriad of different lights you're using. There'll probably be at least a dozen different responses. So when we're using these curing lights, we have some high-quality curing lights, and we have some curing lights that are not of high quality. And I've even purchased some of these lights just to kind of test them out. I can buy a curing light from a source overseas for about $25. And I've used those really inexpensive curing lights to do some workshop courses. So when we were shipping lights all over the country, I don't want to put expensive curing lights that could get lost or broken or destroyed in transit. So we I would buy these really inexpensive curing lights. Now, when we use the inexpensive curing lights and we cure that composite for 20 seconds, sure, the top can be cured and hard. And for a bench top exercise, that's probably good enough. But what you'll find is the underside of that composite oftentimes isn't cured all the way. And you can test this by taking a two-inch thick, sorry, a two-millimeter thick piece of composite, light cure it from the top for whatever your typical curing duration is. Some of you are at 10 seconds, some of you are at 20, some of you are at 60, and then flip that piece of composite over and take a sharp instrument like a scaler and scrape that composite and see if it's hard or if it's scrapable because it's still soft. Now, one of the things I like about the pink wave curing light is that it has that very low profile head. So we can get all the way back there to a back molar, and you can see we have no shadowing of the light. So it is a well-columned light. What does collimmation mean? That just means that we can have a bright light, and if the light that when it's emitted from that curing light just spreads out, we lose the intensity. Yeah, maybe the light's bright, but we lose the intensity of that energy. So we want to make sure that that energy is well collimated, almost like how we think of a laser, but this light is not a laser. But you know how a laser can go a long distance because that light energy is not dissipated, it's directed towards, in this case, the tooth. So this beam collimation really makes sure that the also the way it's focused, it can get down to the deepest part of our box, about 8.5 millimeters, and still cure sufficiently.

Quad-Wave Science And Less Shrinkage

SPEAKER_00 6:32

Now, one of the things that happened is that when I was in dental school, we had a photoinitiator called camphor quinone. And that basically would cure with blue light. So all the curing lights back in those days, back we were using halogen light bulb type of curing lights, emitted a blue light. And that blue light would activate the camphor quinone and we would get our composite cured. Well, camphor quinone by itself has kind of a yellow tint to it. So as we were moving towards the more bleached or extra white shades like we have today, that yellow photoinitiator no longer was the best one for us to use because it would make our composites more yellow. So now we have different photoinitiators and they they basically will be cured at different wavelengths. So now we have UV wavelength light and we have the blue light. But what was discovered in the research that VISTAPEX did was that if you took a near infrared wavelength and added that to the curing light, that you actually got less polymerization shrinkage. And also by using the red, you got a little bit better cure, too. So the pink wave curing light has what we call a quad wave technology because there's actually four wavelengths that are emitted from the curing light. And each one does its job to ensure that we get very good curing, complete curing. So this was a study that was done. I was working with a manufacturer at the time, and basically what you're looking at is you're looking at composite. What you see in the middle is that's a box. And so this composite block had a class two box fabricating it or prepped, and then it was filled with composite and then cured from the occlusal surface. Now think about what happens when you put a curing light on the occlusal surface. Well, the light hits the top, that part cures, then that light penetrates a little deeper, then it cures. And remember, as composite cures, it shrinks. So by the time you have this large volume of composite to cure, and that curing light gets down to the bottom of that gingival floor, everything above it has shrunk a little bit, right? And so you start to create a micro gap at the bottom of your preparation. So that's what this shows is that's the preparation, and that white line is a micro gap created between the resin tooth. This isn't a real tooth, it's a resin tooth, and the resin that was placed in that class two box. The pink wave curing light will actually cure down to 8.5 millimeters, and it was found that decreased polymerization shrinkage by 26%. So if we have less polymerization shrinkage, we have a better margin, which means less marginal staining, uh, less chance of secondary decay gain there, because now we don't have a micro gap that bacteria can sneak up underneath, and a reduction in post op sensitivity. So one of the things where we get post op sensitivity is just doing a class one composite restoration because our C factor is so high because we have five walls around that restoration, and when we cure it, if that composite shrinks, that polymerization shrinkage puts that tooth under a lot of stress. Using a pink wave curing light, we don't see that. Now, one of the things that I notice is that when I'm using a curing light, and maybe we can use a three-second boost or the 20-second standard cure or the 20-second ramp curing, 20 seconds seems like a long, long time. So, what we want to do is we want to make sure that we have a curing light that is able to cure within that 20 seconds, ideally, and we don't have to use multiple lights. When I used to teach courses and we used to have smaller light guides and a big tooth that we're putting a veneer on, I would tell the doctors use multiple lights to decrease your curing time. Because oftentimes, with let's say a five or seven millimeter diameter light guide lens, we'd have to cure the genital margin, then the midbody, and then the incisal, and then come in from the lingual. Today, with the power of the pink wave and the size of the lens, we're able to cover the whole tooth and cure the whole tooth. We have over a 12 millimeter diameter lens, and if I'm doing, say, a molar, first molar, that lens typically will cover the entire tooth. So I don't have to do multiple cures on a tooth, I can just do one cure, and we're able to get a lot of power delivered. So if I'm doing a lot of restorations, this will save me a ton of time. So here's uh the pink wave curing light, and I'm just showing you over a typodont tooth, all that energy that's just being emitted, you know, it comes straight out, it's well collimated, and then just kind of pours over the tooth. And I think that's an important thing. So when you look at the light guide dimensions, the pink wave lens is 12.1 millimeters, and there are others that are much smaller, and that small lens is gonna add up to a lot of time, and that lens on the far right hand side you can see has that curve where we're gonna create a lot of shadowing, and that's gonna create a lot of problems post-cure.

Lens Size And Faster Full Coverage

SPEAKER_00 12:08

So the pink wave curing light also has light guides, and these are really important. So we have three light curing tips. We have a tacking tip, which is a 2.5 millimeter lens, we have an inapproximal diagnostic lens, which helps us to find cracks, we can transilluminate the tooth with a white light emitted from the pink wave curing light, and we have a tight contact curing ball. Now, when I would go out and teach um doctors how to do class two composite restorations, I would get a lot of questions, typically at the break. You know what? When I do my class twos, I'm getting a lot of light contacts or open contacts. And so if you're having that problem, then I'm gonna show you a solution to that. So let's start with the interproximal diagnostic lens. All these just slip right onto the lens of the pink wave. And you can see that this emits a very concentrated light, and then

Diagnostic Tip For Cracks

SPEAKER_00 13:07

we can go through a tooth. The patient says, you know, every once in a while when I bite on this tooth, I'm having sensitivity. We can actually begin to visualize if there's cracks or not. So just you can see right here in that mesiolingual cusp pal, there's little fractures, fractured lines that run from the mesial over to the lingual side of that tooth.

Building Tight Contacts With Curing Ball

SPEAKER_00 13:28

So tight contact curum balls. You know, when we place a matrix, and some some of you watching this use sectional or matrices, and some of you are using some kind of Toffelmeyer. Well, if you're using especially a Toffelmeyer type of matrix, that tightens up around the tooth. But now when we're using those to pack amalgam, amalgam had a lot of body. So as we pack that material into the box, we're pushing that matrix up against the adjacent tooth. Well, today when we use a composite, what we have to do is when we put that matrix over the tooth, we have to burnish that matrix, whether it be a toffelmeer-like matrix like this, or even a sectional, I will burnish that up against the adjacent tooth so I don't have an open contact, which then leads to food impaction, which then can lead to decay. So this is just showing that toffelmire, when we tighten it up, leaves an open contact between that molar and that bicuspid. This is just a recipe for frustration because we're going to end up with an open contact when we place that composite. And that's not good. So here is a ball shape on the end of that curing tip. And what we're able to do is we're able to use that to press the matrix against the adjacent tooth to make sure that we have development of a good contact. And one of the things that I'll do is I'll put a little seam free, which is our composite wetting resin, on that little light guide just so it comes out easier. And when you put your composite in that little box, you're going to take that curing ball and you're going to push that up against the adjacent tooth, but don't sink that ball into the composite because you want to be able to get it out. So place that ball into the composite, push the composite up against the adjacent tooth, cure it for five to ten seconds, and then remove that. And you can see we're starting to get the creation of a very tight contact against the adjacent tooth. Now just don't place that curing ball too deep. Here you can see the white, which represents the composite, is wrapping over the top of that ball. And if you cure that now, you're gonna have a hard time getting that out. So as you go and you begin to fill that box up, you can see we start to get a very nice shape developed. And so if you're having problems getting tight contacts, this curing ball can be very helpful. Just put the composite in the box, and this is just showing taking that curing ball. Again, don't sink it too deep into that composite, but press that Toffelmeyer light matrix up against the adjacent tooth and then pull that tip out. Now you're gonna have a really tight contact, very easily developed. All right, now the one that I use the most often is a 2.5 millimeter tacking

Tack Curing Crowns For Clean Margins

SPEAKER_00 16:22

tip. Now the tacking tip works really well when you're doing things like veneers, but it also works really well whenever you cement a crown. So what I'll do is I'll seat my restoration, either wipe off the excess at the margins. Let's say we're doing a crown, I position the crown, all the excess cement comes out. That's usually either a light-cured or dual-cure cement that I'm using. Then I will tack that restoration at the at the margin for about three to five seconds. That prevents that crown from moving, right? It locks it on. And now I go through and I floss the mesal and distal, I wipe off the all the excess on the buckle. And remember, we've only cured really about a 2.5 millimeter section of that margin, so I can clean up the rest of the margin before it sets either with time or with light. And that simplifies the curing so much. Because I know a lot of you will place that restoration, you'll see all that excess cement, and you'll wipe off as much as you can, then you'll cure it. Well, you still have a lot of cleanup you have to do. Or I know some of you you squish that crown down, you see all that excess cement, and you go and just cure it. So, what this is allowing you to do is, and the reason why you do that once again is because you don't want that restoration to move. So now you can push it down, light cure a small section. Depending on your prep, if you've got a very retentive prep, I just cure usually on one side, either the buckle or lingle, whichever side is easier for me to access. If you've got a really short prep and you want to make sure that it doesn't move, then cure from the lingual and the buckle just five five seconds using the tacking tip. Half of the tacking tips on your restoration, half it's on the tooth, and you just cure that. So now that restoration will not move, and you can wipe off all the excess and actually floss the mahesial and distal, and again, it's gonna save you a lot of time. So here I'm putting two crowns in on eight and nine, the one one and the two one. You can see there's a lot of excess cement. Just wipe off that excess cement, bring that tacking tip up at about a 40-degree angle there, and just cure that for three to five seconds, and you're only gonna cure at the margin. You're not gonna cure all the interproximal, you're not gonna cure the lingual, but that's gonna hold the crowns in place. So you floss, do the majority of your cleanup, and then you come back and do your final cure. And just showing you, you can see these centrals are fairly long centrals, but we were able to cover the entire central with the light guide of the pink wave and cure it all at once. So this is the pink wave, it is a high-intensity curing light, it will flood the tooth and the mouth with light, and that's what you want because you don't want to be guessing if your restorative light-cured material cured or not.

Heat Control Positioning And Final Rules

SPEAKER_00 19:19

So don't compromise on the light. Make sure that you have a curing light where you know it has sufficient output. It's a quality light. It make sure the lens is clean because now with this pink wave, it's well collimated, but we don't want to block out the light that exits the lens. Keep the light close. This is a high intensity light. If you put the light guide by your finger, you will feel a lot of heat because that's what light is it's energy. So, in some cases, just kind of feel where that heat is, and you may not hold it right on the tooth or right on the gum if you're doing a cervical type of cure. Just hold a little bit away. Your assistant can actually hold a suction in that area, just keep the air moving. And remember, this will cure to 8.5 millimeters. So if you're doing, let's say, a class 5 restoration and you don't want to lay the lens right on the tissue because it's gonna be warm, you can hold it a few millimeters away. Suction is pulling the air through that area, keeping that area cool. Works really well. And remember, remember about the shadows, position that light guide so you don't create shadows where you need that light to cure the rest the restorative material.

Next Steps Community And Subscribe

SPEAKER_00 20:33

Now, what we're gonna talk about next time I'm with you. Well, we might have a little bit of a break on the bioactive uh materials, but we're gonna talk about the bioactive glasses again. I just want you to understand what it is that we're using to place these restorations, and that is in large part the reason why we had the success. So, next time we're talking about the biota glass, we're gonna be talking about uh wetting resins. We'll be talking about um just ways of making our life easier, like warming the composite so we get better adaptation of our composite to the walls. We've got a lot more to cover, so I'm looking forward to it. So, what are your next steps? Remember, subscribe to this YouTube. You don't want to miss the next couple weeks that have some information that I hope will make your clinical life much easier. Remember to tell a colleague types of presentations, but we'll have information that I think will be worthwhile for you to learn. We are creating a community of like-minded individuals focused on providing the very best care for their patients. It's interesting because this week we had a patient that called our office asking where they could find a clinician using the bioactive regen materials close to them. They don't live close to our office, they're a couple hours away, but they're thinking about coming in just because we use the regen materials. Anyway, I look forward to seeing you next week. Take care and have a good one.