Ceramic Onlays from Preps, Temporisation and Bonding Protocols – PDP059

Jaz’s Introduction: Hello, Protruserati and welcome to Episode 59 of the Protrusive Dental podcast. Thank you so much for joining me. As always, this episode is wow like so jam packed. Like every sentence like you’ll have to definitely grab a pen and paper for this one is one of those crazy ones. And I know you will love it so much and I’m so excited to share it with you. Before we get to that I have some cool news. I’ve done a few extra videos I have one on YouTube on how to take occlusal photographs which you can just search for it. But recently one of my buddies [name], he asked me can you make one on how to take posterior quadrant photographs. So I show how to use the long buccal mirror and that’s all on the website also on YouTube. So check out my channel if you’re interested in how to take photos for posterior quadrant dentistry. I want to say a warm welcome to all the new members of the Protrusive Dental community. Thanks so much for joining guys really appreciate it. If you haven’t checked out the Facebook group, it’s called Protrusive Dental community and one of the listeners, one of the Protruserati, shall I say message on that asked if we have a whatsapp group. We don’t but now because of the demand like that thread has got like 80 plus comments of dentists of the Protruserati who wants a whatsapp group. So it’s coming soon guys, as soon as the splint course is done, and out and ready, and I’ve done the whole launch has been taking up all my time at the moment. So once that is done, then we will have a whatsapp group just to Protruserati. I want to give four more shoutouts before the Protrusive Dental Pearl and then we will have this epic episode with Nik Sethi. So the first Shoutout is for Sai Mehta, who is a great young dentist, buddy, thank you so much for all your support, also to Taha Adamji, who has made some phenomenal notes on those episodes with Zak Kara, Episode 10 and Episode 40 something on comprehensive dentistry and treament planning, you have done a wonderful job of making notes, which I’ll be sharing on the Protrusive Dental community as a PDF download. So thank you for taking the time to do that. And if anyone else because I know some of you guys take notes on the episodes, if you can just email me those notes and I can share them with the community. That would be amazing. Shout out also to Jenny from snowy Norway. Thanks so much for tuning in from Scandinavia. And last but not least, I’m going to read out an email that I got, which is just, you know, one of those moments where you think wow, just Wow, what an impact. And it made me so grateful to be able to have this platform with you guys. I really appreciate you guys listening and his emails like this and that which really just validate and keep me going and keep me podcasting. Right? So thanks so much. I’m gonna read out. I’m not gonna read out your full name because I don’t wanna embarrass you in any way. So it’s from Adam says, “Hi Jaz. I just want to reach out to say what a fantastic job you’re doing with the podcast.” – Thank you, buddy. “I’m a 40 year old GDP working in a city I won’t name and up until have felt stuck in a rut and had become a bit despondent with dentistry. Your infectious enthusiasm that you show your podcasts and your YouTube videos has really helped me reignite my passion for dentistry and I’m really enjoying learning then. The guests you have on the show are so interesting and so knowledgeable. I particularly enjoyed listening to the master that is Finley Sutton. I could listen to him talk about dentures all day.” I think we all can, Adam. “I’m enjoying my job so much more now. And you have even started a distance learning MSC program. I won’t which uni and I’m doing that alongside my job. Keep up the great work. It’s always great when you have one your new episodes drop and I can listen to them on the way home from work. Myself and many others out there. I’m so grateful for the work you put in. With all the negativity in the world right now. I still feel feels important to give people some positive feedback and praise where it’s due. Thanks again Jaz, Adam.” Adam, honestly, what can I say you have made my day, month, week, year with that email. That’s one of the sweetest things I’ve ever had. So thank you so much. I’m so so pleased that it’s made you more passionate about dentistry again, which is exactly the mission I’m on now, before it was it was a fluke that I made the podcast but now I feel like I have a purpose which is to help dentists become the best version of themselves. So thank you, Adam, and thank you everyone who have given a shout out to and thank you who’s listening or watching right now for tuning in today. The Protrusive Dental Pearl I have for you is a splint one and is dedicated to Tilly Houston. Tilly, thanks so much for listening to podcasts you sent in a slide from a lecture you went to at Queen Mary’s I believe, and it was about the use of air abrasion or sandblasting on a Michigan splint for a couple of reasons. And the reason why you would do this and typically I would usually do this when I’m checking for compliance. So by air abrading the Michigan or Tanner appliance, when the patient goes home and comes back and when they’ve parafunction on the appliance, you will get these polished areas. So you know they’ve been wearing it, right? And if they’re not wearing it, it still remains sandblasted or that’s how it goes. Now Tilly messaged me about that, “Hey, Jaz, have you heard about this?” But also, she also taught me from what she shared with me was that you can actually use it for getting your contacts as well. So when you’re checking your contacts, it is one of the problems is that when you’re checking with the articulating paper is difficult to get the markings on the polished surface. It’s only after I’ve adjusted it with the acrylic bur that I can see my contacts are much better. So to check your contacts if you actually air abraded or sandblasted the Michigan splint, then your contacts or articulating paper marks will show up much better. So that’s a great pearl. Tilly, thanks so much for sharing that with me. And so guys straight over to the main interview with Nik Sethi. Man, you will love this. Enjoy.

Main Interview:

[Jaz]
Nik Sethi, Welcome to Protrusive Dental podcast. How are you my friend?

[Nik]
Amazing, mate. Thank you so much for having me on this evening.

[Jaz]
Dude, I can’t think of anyone else who is so anal about getting their onlays on so beautifully. And every time you blow them you know this, Nik, every time you post a case on Facebook, right? And I was like, Wow, that’s awesome, right? And then you’re like, oh, by the way, this is a temporary and you just crush all our hearts.

[Nik]
No, that’s that’s definitely not true. My temporaries are okay, but they’re not as well. My brother’s temporaries they are another level. My temporaries are alright. Basil and Sanjay’s temporaries, I can’t touch them there..

[Jaz]
We know all about Basil and Sanjay’s temporaries. But not everyone I met. What I meant to say was you know, you could take every photo so well, when you post on and it such a something that you want me now I know your passion about lots of various dentistry but I know a [inaudible] and onlays and stuff, something that you’re quite hot on. And that’s exactly what we’ll be talking about today. And we’re gonna talk about like the really, really big things that comes onlay, that how to make them look invisible, how to temporize. That’s a massive one. That’s a biggest pain that Dentists have right how to temporize. We’re gonna cover that. We’re gonna cover about your learn about your workflow, you know, do you do IDs, do you not? What’s like your workflow? And that’s exactly what I’ve got you on for today. And I know you’re so passionate about it. So I’m really excited to have this chat. But before we do get into that, Nik, tell those people listening all over the world, who don’t know who you are, a little bit about yourself, what drives you, where you work, that kind of stuff.

[Nik]
So my name is Nik, I’ve been working in private practice in London, a practice called Square Mile Dental Centre for the last 10 years now, I can’t believe I’m already 11 years qualified, it’s crazy. And I did my qualification at Kings and I went back to do a masters in aesthetics at Kings as well. And I work for my brother, who is Sanjay Sethi, and a previous president of the British Academy of aesthetic dentistry for which I’ve just become scientific chairman. So big, big bruise to follow from Rob Oretti and Sanjay and people and so on. And Sanjay from day one, told me one thing that I would never forget. He said, Look, forget all the magazines and the posts you see on work looking pretty. He says, You’ve got the rest of your career to make things look pretty. So make things look beautiful, but if it doesn’t stick, you’ll spend the rest of your career replacing it. And so He hammered me on protocols, Jaz, I mean, literally my nurse Shaz, she’s like a second mom, she was like a spy, the number of times she ratted me out is amazing. His son would be so a naughty I’m so angry. So I know about protocols and adhesion dentist somehow think that we’ve got this right to be scientists, we’re not scientists where the end user of a toy that’s been made by billions of pounds of research by people that are far cleverer than us. So talking about what drives me, what drives me is the inspiration behind the people that made those products and those protocols and the science of how they got to those protocols. How did they develop this chemistry to be able to bond a tooth which is got water in collagen fibrils and provides a restoration that can bond to it and change it to a hybrid layer and make a restoration last 15, 20 years. For me it’s bonkers.

[Jaz]
That is crazy.

[Nik]
What breaks my heart is people abuse the protocols. You know what one right didn’t have to abuse those protocols set by the guys that have done so much research. So Sanjay with literally I mentioned this day, at the end of every week. And all I wanted to do at the time was go out and party. You know what it’s like I was 20, 21, 22 and San, he would sit me down on a Friday. I’d have to show him all my before and afters for the week. Every single one on the intraoral.

[Jaz]
This is you as a student?

[Nik]
No, this is me when I started working at Square Mile. So they put me through a rigorous six month training program. And he’s done that to every associate to be fair, and we have to show him our photos before and after. And he puts a kitchen timer in every surgery, and the nurse is pressed timeout, press start when you start the etch, and she will not let me wash until it’s hit 30 seconds. And then she was drying until it’s washed for 30 seconds. So from minute one, I didn’t have a chance to fall into bad habits. So I’m very lucky. It’s not because I’ve got a gift or an incredible brain, I’d like to consider myself as fairly academic and I enjoy studying. But when it comes to hand skills, my brother’s the opposite. He may not be as as naturally academic, but I’ve never see well, very few people I’ve seen with natural hand skills like him. So he really whipped me into shape. And that inspired me because I realized in dentistry people are very lonely. They find that very challenging. They’re constantly comparing themselves to this university of Facebook and Instagram. And realistically, you need a mentor, you need a collective of people around you, whether it be an academy such as BARD, PACD, Dentinal Tubules, you need like minded people that you can openly discuss your failures and I’m very lucky to have that. So if I can do my bit to help drive people to say that it’s okay to fail, because Lord knows I’ve failed many times, then that for me to see the light come into someone’s eyes like Sanjay did for me is a lovely thing.

[Jaz]
That’s brilliant. I can just say I’ve got visions of at the end of the day, Shaz going up to Sanjay was like, he didn’t use the 2% chlorhex rub and he only air abraded the mesial part, but he missed that distal part, or, whatever.

[Nik]
She’ll kicked me under the chair. If I forget to put a second layer of bond or something, she physically kicked me.

[Jaz]
That’s fantastic. Well, let’s dive right and ask you, the first clinical question, which is a bit about decision making, right? So every Clinician’s is different. What features of a tooth have a cavity of a fracture or just any toothpaste or a quadrant makes you the more towards an indirect restoration than a direct restoration? So what is your threshold? Is it the same as what the textbook says, you know, more than a third of isthmus, root field, that sort of stuff? Or are there so what’s your sort of decision making process with regards to that?

[Nik]
It’s a really interesting question. And I think decision making changes all the time over the years. And I always when I start my lectures, I always talk about traditional concepts and minimally invasive and whilst we mustn’t forget the traditional concepts, we also shouldn’t just blindly believe, for minimal invasive dentistry, we’ve got to have some, a lot of Didier Dietschi coins that beautifully minimally hazardous dentistry, you’ve got to appreciate the limits of adhesion, and also move away from heavy preparations where we can so there’s a wonderful article by Marco Veneziani , who spoke at the British Academy a couple of years ago, and it’s an article I recommend everyone to read. And he says that the best way to answer that question that you’ve got general factors and dentists, you know, you’ve got someone comes in and pain or a fractured cast, we’re very quick to just stick an ID block in and crack on. But we’ve got to look at General factors, meaning where’s that tooth in the arch. So I might treat a cracked Upper premolar. I have a patient who’s got canine guidance with no lateral contact differently to how I may treat a lower left seven, with a strong upper medium palatal CUSP with history of fractures, clenching and dietary habits. So the general factors would be the position of the tooth in the arch, the presence or lack of anterior guidance, the depth of occlusal schemes if they’ve got history of fractures or parafunction, and multifaceted issues such as tooth wear, say we’ve got our general facts, of course, but we’ve also got to appreciate the local factors and that’s what all dentists are pretty good at. And essentially, those factors have changed. So traditionally 1/3 or more of the isthmus, but now it’s been shown by Didier Dietschi, Pascal Magne, [inaudible] but on a vital tooth. Even if you’ve got one millimeter of residual cusp width, that’s enough thickness to be able to keep a wall with a good adhesive restoration. You know, today’s restorative composites are fabulous. So I do not take the decision to hack down a cusp lightly with the fact that these composites such as Venus diamond, GCs, G-ænial, ENA HRi , you name it, there’s some fabulous systems on the market. If I’m missing both marginal walls, if I’m a millimeter and an MOD cavity, I’m going to start thinking this is higher risk. Then if you compound that with endodontic treatment, and symptoms, cracks, you’ve got to start thinking. I must admit, I tried to be a bit more of a hero earlier on in my career and try to avoid because I thought I was being minimally invasive, but you’re not really because when that Does fracture, you’ve then got a bigger crime on your hands. So now I’m a lot quicker to decide to partially cuspal coverage doesn’t mean I’m hacking away buccal and lingual, but if I’m worried about one cusp, I will bring that down. Concerning a millimeter, 1.5 millimeters and then overlaying it with composite. And if it’s, I feel that that’s not going to work for that patient, then I’ll weigh up and decide to go indirect, which more often than not, because I don’t have a milling machine, will end up being a lithium silicate restoration.

[Jaz]
That’s a fantastic. Very comprehensive reply on [inaudible]. And definitely I’ll link to that paper you mentioned, for general reading. So I put it on the website, the show notes and on the Protrusive Dental community where, Nik, you’re welcome to join as well. So we’ll add that paper on, which would be really cool. It’s interesting. So about a millimeter remaining. Let’s say for example, buccally palatally, it makes total sense, because how many massive amalgams Have you seen where the patient comes in, and they’ve broken off the mesial buccal corner? But How long ago was that amalgam restoration placed? It’s been there for 30 years, right? So you’re completely right, with these modern additive systems, then I’m sure that will hopefully surpass it or change the mode of failure in a more favorable way, would you say?

[Nik]
Definitely, and it’s a fine balance, because dentist has to realize that whilst the adhesive material is getting much better, you can’t deny function. And this is what Riaz is really hammered into my brain. This whole, patients don’t just bite and grind left and right, we chew outside in, we’re hammering these cusps all the time. And if you don’t appreciate that function, and you rely purely on adhesion, you’re gonna lose because the body’s gonna win. But on the other hand, this whole thing of like, you say amalgams that I keep saying to patients, you know, Mr. Smith, we’re gonna have to replace this, but I will let the tooth tell me I went over to, and it’s still there five years later, six years later, it’s it’s amazing. And it’s very much case dependent.

[Jaz]
I love that what you said that quote, Mr. Smith, I’ll let the tooth tell me, I’m definitely gonna borrow that one. So that’s great. That’s a real gem right there. Next question that Nik is, talk us through your protocol, because I know you’re really hot on protocols, Sanjay has read drill that into you, right? So tell us about specifically, we know that the bond between ceramic to enamel is one of the strongest bonds in dentistry. So tell us you’ve got your rubber dam on, you’re doing a lithium disilicate onlay. And you’re about to fit just to briefly describe your standard adhesive protocol.

[Nik]
So we’re skipping past the first stage of the prep and IDS where we’re talking about the fit stage, right?

[Jaz]
You know what I would like your take on, I would love to hear your take on IDS as well. And you know, which global you use, you know, what adhesive system you use that kind of stuff. So if that let’s roll it back a bit, let’s talk about IDS, and then let that lead nicely to the fit appointment. And talk us through your protocol that I think we can learn a lot from that.

[Nik]
Yeah. So I mean, that’s probably more logical way for me to explain it. So traditionally, what I used to do was, I used to take out my restoration first. I used to build up the tooth with their core filling. And I’ll talk about the adhesive steps in a minute. And then I would prepare the tooth. What I found in my hands is, I found that took quite a long time to build up a core filling wait for you know, cure it layer by layer by layer. I didn’t see the point of it. And if the whole goal was just to block undercuts, then I thought, Well, why don’t I get my prep done first. So I leave my amalgam in, I will do my depth cuts, I will do my reduction, I will do my variable margins, which we can discuss later how I blend in my margins to make the ceramic look not invisible, but as close as I can to the enamel. Once I’ve done my margins, and I’ve done my contacts, and I’ve done my depth cuts, at that point, there’s not much restoration left, I remove the amalgam very carefully or whatever they are caries or composite. And at that point, I don’t have a massive job to do in terms of rebuilding. And with onlays. We’re not trying to rebuild a whole core because we want 2, 3 millimeters for the ceramic, we want the strength of the Emax. And I don’t understand when people are doing these big core fillings and then saying we only do 0.5 or 0.7 millimeter reduction. And I’m thinking is bonkers. It doesn’t make sense. whopping great big restoration in the middle. Why not have a thicker layer of ceramics. And the first thing is I make sure that I don’t even call it a core filling. We call it a mini core. So we’re essentially we’ve got rid of our amalgam. I always use air abrasion with aluminum oxide. And that’s because as you know, when you cut with a diamond bur, what we think looks nice is essentially hundreds and thousands of microcracks. It’s like throwing a stone at your window sale. You get all microcraks. So what an air abrasion system does is, it removes all of that so you get a nice clean surface, but also any oil from the handpiece, any residual biofilm that’s going to massively impact that adhesion is then gone. You don’t have to get a massive expensive unit, I bought a two, two and a half grand prep start unit people buy an aquacare unit and these are great and I’ve worked my way up to be able to afford and by that and save for it. But you can pick up a micro etch for 2, 3 pounds..

[Jaz]
The latest trend, Nik, I don’t condone this but the latest trend because I’ve got a few buddies on Instagram who told me this, is their 80 pounds on eBay they go for a [inaudible] I don’t condone it in any way but they’re out there you know we know that [brand] are out there. We know that [brand] any country is over systems of air abrasion but nothing beats the gold standard like what you’re using but yeah, these are their options do exist.

[Nik]
Okay, perfect. So I said once the air abrasion is done. Then at that point, I’ve got a nice clean surface. And since I’ve been using microscope, honestly, the change is incredible. Even from loops to microscope, the surface you see of air abrasion is just stunning. It just looks like it’s ready to accept resin. It’s lovely. At this point, depending on my goal, my adhesive protocol changes. If I have not got a deep margin, and I’m not planning on doing deep margin elevation, if I’ve got nice supragingival margins, then my only goal is to seal the dentine and block the undercuts. And with flowable and maybe add a touch of composite if it’s too deep, and I don’t want any more than three millimeters of lithium disilicate has been shown by Professor Dr. ArcAngelo. If you’ve got more than three millimeters of lithium disilicate, you’re like your unit struggles to penetrate to cure the cement underneath. So three millimeters are critical level, and that’s quite easily achievable. He just measured to the adjacent marginal Ridge with your IMC probe. And you just build up your core to that point if you overdo it, or you can just trim it back. No big deal, right? So if I’m not going to do deep margin elevation, I’m not really bonding to any enamel. In that case, I generally don’t etch, I will go to a self etch system because I’m purely adding to my dentine. I like to use OptiBond™ XTR, I use a dedicated two bottle system, which is a separate self etch, and then a separate bond. Maybe because I’m pedantic and Sanjay has knocked into me you’ve got fabulous bonds such as G-Premio BOND, CLEARFIL™ Universal Bond and they all have the MDP monomer in, they all have the ability to self etch and I’ve no doubt that’s where we are going and I know I’ve no doubt they work terrifically well, but not having any trudy bonds in the last eight years with this system. It’s difficult for me to change when it’s not taking another 20 seconds right. So I like my water chemistry and I like my dry chemistry separate that’s that’s how I feel. So I do my self etching primer-dry-bond-dry-lightcure. I always light cure my bond for 40 seconds. Again being pedantic.

[Jaz]
Valo or no Valo?

[Nik]
Always Valo, man. I can’t do anything without my Valo. And that’s not a [inaudible].

[Jaz]
40 seconds of the Valo is like three minutes with a normal life.

[Nik]
You know, it’s funny because I keep saying it doesn’t work like that. Chemistry is so funny. I remember when I first got it, I was thinking yeah, wicked I can cure this layer in five seconds now. But anyway, we’ll go off topic, but essentially, the power diminishes so quick, every millimeter you move away from the tooth, the almost hard. So essentially, if you’re six, seven millimeters away from the face of that cavity, you’ve got to give it time. And especially if you’re not using a powerful like your unit, if you’re using something that’s under 800 milliwatts per millimeter squared, you’re gonna get poorly cured adhesive. And this is why we see marginal staining, and post op sensitivity on class two composite because we’re not respecting the light. It’s like A Bug’s Life. Don’t look at the light, you know, light. The light is so important. And it’s, I always say to dentists, it’s the easiest part of the whole process. But we don’t give it enough credit. And we’re not light curing, we’re like activating, we’re starting a free radical reaction that will then carry on over the next 24 hours. So once we light cure I then use them flowable composite for the FIPO protocol, we use their G-aenial Flo, which flows really nicely, the universal injectable because it’s not too runny and you don’t want it running off the sides of the tooth. It’s quite nice to handle. If I’ve got dark amalgam stains or residual dark brown color from caries, then with lithium disilicate, if you’re going to use a high translucency block, which we’ll come to later at hiding margin and becoming invisible. Any grayness will show through and it breaks the aesthetics. So you can either use a more opaque block, but then you use that ability to blend. Or you take something like a baseliner from Kulzer, you get the Venus Baseliner, which is literally, I call it dental tip x. And it’s a drop of that, and it just completely masks it. And then I just cover again, with a touch of flow, [inaudible], we’re done. And in most of the time, I don’t even need to then go ahead and put composite on, because I’m usually at that point within three millimeters of the marginal ridge, I don’t need to build any more. If it’s a very deep cavity, I will then use my G-aenial posterior composite to then put a mini layer on to build and then cure it. But essentially, it’s very quick. Rather than rebuilding a core filling, putting matrix bands on and stuff I don’t need to I’m controlling where I put the flow. The whole process of the mini core takes me no longer than about four or five minutes. It’s very quick.

[Jaz]
I mean, you’ve got your mini core, but that is essentially doubles up as your immediate dentin sealing. Is it fair to say?

[Nik]
Absolutely. And in fact, one step further than that. There is a problem if you’re just immediate dentin sealing, the layer of bond we use for people that aren’t using a thick bonding agent such as OptiBond™ FL or OptiBond™ XTR, if you’re using one of the older generation, all in one bottles. Then what happens is your adhesive layer’s too thin, and you get an oxygen inhibition. So if you’re light curing, some of the adhesive layer doesn’t actually set. So you still have an uncured resin, which basically means your dentine isn’t sealed. So all the problems, you’re going to get possible sensitivity, poor bonding strength at stage two, these things can be easily over come by just adding a drop of flowable over the top to block that oxygen inhibition layer. And then you get the benefit of curing the adhesive fully because it’s blocked. And you can control the color and undercuts with the flowable.

[Jaz]
Brilliant. I love that. That’s fantastic. And you’re scanning at the moment, you’re taking What’s your flow at the moment?

[Nik]
I’ve just been scanning for the last year, we’ve just bought TRIOS 4, 3shape. And it’s lovely. It’s not without its learning curves. It’s not without its problems. So I wouldn’t say I put your impression materials away. It’s a learning curve. Now that I’ve got used to it, I hiked the dream, it’s lovely, because one of the biggest things is you can check your prep, and you can check your clearance immediately. Which for me, me being just the same as any other dentist I do what everyone does, I often used to under prepare the occlusal surface, the mid occlusal. And we used to complain our labs when we get a very thin onlay, but they’ve had no choice, we’re very quick to blame our labs. But if we don’t give the correct space for them, you know, they’re not Harry Potter, we’ve got our way either my lab would phone me in the past and say “oh Nik, there’s not enough space.” Either I’ve got to get the patient back numb up again, take off the temporary re prep or they make me a reduction jig which loses the accuracy of these minimal prep onlays which I don’t like. So with scanning, I can just check my clearance and I can see very quickly where I am. So from that point of view, it’s great, patient comfort wise obviously is through the roof and they love it from a patient perspective. It’s great for a I guess sellings a bad word but it’s from a communication tool. It’s been fabulous and just that digital design, being able to see the wax up design digitally the next day is amazing or no I don’t like this incline I prefer if we can avoid that contact. Normally you just rely on the labs just doing what they do or maybe they show you a day before the appointment you know which is no good.

[Jaz]
Absolutely and that said that function of checking the clearance has saved me a few times often the functional bevel area buccally where I’ve perhaps underprepared and be able to check out let me go back rub that bit out, prep again a little bit, give that bit of space. It’s just a dream also using the 3shape so that’s been great as well. So you’re now going to come on to the actual fit appointment and the protocol that’s you beautifully described the, your IDS version if you like, blocking the undercuts.

[Nik]
We forgot about the temporary because that’s not easy, but either.

[Jaz]
Can we get the temporary at the end because it’s temporary I want to give it a whole section because temporaries are so so I mean, everything is important don’t get me wrong, but temporary is I if you look at the because what I do is I’m wanting to on Facebook, the kind of questions people are asking what not and huge one is how can I get my temporary stick, right? I just wanted on the theme of protocols, I would love to get your the rest of your protocol and that can be chaptered off as the protocols.

[Nik]
So the one thing I forgot to mention is if I do have a deep margin, which is equigingival or just slightly subgingival then I have to make a decision because too many times I think I managed to isolate that at visit one I’m so good. When you come to Try and isolate a visit two, it’s a whole different ballgame, trying to get a rubber dam around the deep margin is much more difficult than putting a rubber down around the tooth and the margin goes deep. That’s okay, we can handle that. There’s so many times where I’ve been sweating trying to fit in onlay in the past, where I’ve got these deep margins, so at visit one I was giving myself a pat on the back. So just to rewind, if I’m going to be doing a deep cavity which has gone subgingival or a fracture, then I’m going to consider two things, I’m either going to consider crown lengthening, and then putting the rubber dam on immediately, and doing my deep margin elevation. But a lot of the time has been shown by a wonderful paper getsy in 2019 in the European Journal, that we were always taught this thing about biological width, you must have three to four millimeters from the crestal bone to your margin of restoration. And that was true for traditional prosth when you’re cementing a crown. But it’s not true for composite which blends in and you’re polishing the margin to a flush finish with tooth, you don’t have a fit of such you can get within 1 to 1.5 millimeters of crestal bone. And as long as that composite is smooth, the bone tolerates it superbly. So as long as you can isolate it, you can do deep margin elevation, only if I can’t isolate it when I then do crown lengthening. So if I’m doing crown lengthening, I will etch the enamel especially if there’s a little ring going up the walls, I want to make sure I etch that enamel because I will be bonding to enamel so then, there’s no chance I’m going to rely purely on self etch, I’m going to etch. Then we build up the composite for deep margin elevation. The reason being, I want to build up to make my margin supragingival. So that answering the next question, firstly, rubber dam placement is easy as pie. Because that is tricky. So deep margin elevation is a game changer for your second stage protocol. So now we come second stage, we get the onlay back, I check the fit. The nice thing is usually at this stage, I don’t need local anesthetic because I’ve done the mini course sealed all the dentine, generally, there’s no sensitivity. So you know, no one likes to put ID blocks back in for a fit and lots of local a lot of the time I get away without it. Temporary comes off, we clean it with a bit of air abrasion again, I check the fit of my onlay, I check the, lightly check the occlusion, I check the contacts, everything we normally do. And roughly check the aesthetics. Emax will always or lithium disilicate or LiSi whatever you use. With lithium disilicate, will always look brighter before you cement it. Once you cement it really acts as a contact lens that absorbs into the tooth. So at that point, my rubber dam then goes on. The onlay I go through my bonding protocol, we do the porcelain etch, I use the bond from ultradent. We then wash, we dry, I then use the I don’t have an ultrasonic bath yet. But I need to get one because apparently that [inaudible name], he said Nck you have to get a Sonic bath but I’m just using normal phosphoric acid etch after to try and remove the salts, which has proved not to be so effective, but I’m still doing it, then I prefer to use a separate Silane and then apply a bond and then you get these [inaudible]. But I prefer the chemistry to be separate. So we apply the Silane for five minutes, while the silanes going on, my rubber dam is going on. So I’m not wasting time. And I get my nurse to do a bit of this as well. So it helps, she helps me out.

[Nik]
Once the rubber dam goes on, then my onlay is ready to go in the heater. I put my onlay in the heater. This is a critical step. Because I cement all my onlays, the LiSi onlays that were used, I cement them with heated composite because I find number one, the aesthetics is incredible, which we’ll touch on later. But also the handling. Everyone in this room in this podcast knows how to handle composites, everyone’s struggles to handle luting cement because they go everywhere. And no matter how much you try and clean, you take that by a year later and you just see a bit of extra cement sometimes you think how am I going to get rid of this, then you’re there with scalpel blades, you know, whereas with composite heated composite, it just goes on like butter. So the tooth is ready, I will do a total etch technique this time because there’s no dentine exposed. So etch the whole thing, the enamel, the composite, air abrasion, so my composite is fresh and ready to go. Then use a same bonding agent which contains MDP. But at this point, you could just use a standard universal, 3M Scotchbond™, G-Premio BOND, universal all of these things, because there’s no dentine involved. So now you’re back on Easy Street. You can use whatever you want. Once that’s done, if you talk to the chemist, they say you must secure your bond, because you need to get that bond strength. If you talk to any dentist out there who has done that a couple of times, and you’re onlay then doesn’t fit, you don’t.

[Jaz]
So you definitely don’t, right? Cuz I was I was thinking, yeah, I’ve read that, you know, some dentists, you know, some instructions say cure, but I’ve made that mistake before and it’s not quite sitting as it should do. So the real world clinical advice is, it’s impossible.

[Nik]
It’s impossible. Well, it’s not impossible, because I have done it, and it has worked. But I mean, do you really want that to be the step that wrecks your whole, the whole plot of the story, right? You don’t want that. And you know, using a light like a Valo I’m pretty confident this thing is going to get through a brick wall, let alone a thin 1, 2 millimeter onlay. So we don’t cure, we dry, we air thin, and then my onlay comes out, which is warm, and then I apply warm composite, heated composite. Composite is an insulating materials even if you heat it, it loses temperature very quick. So by the time you faff around putting hot composite on a cold onlay, it’s already cooled down, and it’s going to be very stiff. We use the G-aenial because it’s quite nice to handle but previously, I’ve done hundreds with Venus diamond, which is lovely material as well, but it’s very stiff. And if it loses its heat, you’re not sure if it’s fully seated, you press, you remove the access, you press a bit more and more access in thinking calm when it’s going to stop and I have had a couple of incidences where I’ve tried to do a six and seven together, that by the time I get to the seven, if my nurse hasn’t put the composite back in the heater, the seven didn’t fully sit. And I took a post op extracts it didn’t feel right. And you think man nightmare. So a hot onlay. And making sure the composites back in the heater when you’re not using it, is the way to get around it. Composite goes on, I press I use the LM-Arte™ instrument a Fissura, the green Fissura, that we do posterior anatomy with, we remove the excess with that, Elaine taught me that trick actually it’s lovely. We remove the excess, floss the contacts, keep lots of pressure on the tooth. And then we ligth cure it for minimum one minute per surface buccal lingual occlusal. And then I go around another 20 seconds using an air blocks such as Oxyguard or liquid whatever it’s called is this few on the market like light liquid barrier. Then the nice thing about that is because composite drags together, there’s no cleaner, I’m not spending more than literally, the only thing I spend then is adjusting occlusion if I have to, there’s no cleanup as such, because everything’s just dragged away nicely, I might use a composite brush over the margin, just to make sure that as you’re dragging the composite, it doesn’t pull between the composite, between the onlay and tooth, I would use my Fissura and then go over it with a brush. So there’s no dragging. Then we set it and remove it. Check occlusion, adjust. And I have to say it’s the least stressful adhesive cementation technique that I’ve had for years because I used to use you name it Multilink, Panavia flowable composite, a lot. And I never enjoyed it. I’ve never enjoyed cementing with a dual cure composite. I just, I’m a slow dentist, I take my time. And I don’t like the fact that someone’s telling me I’ve got one minute to clean this thing up. It’s a stress I just don’t need in my life, Jaz. And so with a dual cure composite, you know if you’re not quick, and it’s an upper left seven with a patient with difficult access. It’s not fun. It’s really not fun.

[Jaz]
It’s not fun to use those little interproximal sores there. Trust me, I know.

[Nik]
Exactly. And the other thing with dual cure composite is, I know they’re getting better and the color stability everyone talks about a Delta numbers and they’re getting better and better. But you put it in a smoker, and you show me four years later because I’ve done it and every time on these ones where I’ve left the margin in the mid buccal aspect thinking I’m amazing. When they smile, I can see a little stain line. And it breaks my heart because I followed all the steps. And maybe it was my hands, maybe I’m just not good enough with dual cure composites. But having found that since I’ve been using a true light cures nanohybrid restorative.

[Jaz]
Amazing. Man that protocol was amazing. And I know for those listening out there who maybe struggle with these mini steps, I think you’ve covered it so well that’s worth another Listen again and again again because that’s how well and you float it so nicely. An interesting point you made about how composite drags together and how you can use the composite brush for example, to just brush the margin and use that Fissura instrument and I believe there is some evidence might have been by John Canker that if you use rotary instruments to clean up that you actually end up getting a void or a gap. I think David Gerdolle told me that actually in a Tubules lecture, and so, so much better to use like you said the brush to brush it out rather than using the rotary instruments afterwards. And I imagine you don’t get as nice of a finish by using rotary instruments afterwards.

[Nik]
Of course. And, you know, how many times have you seen a patient that’s finished ortho, and you can see a tiny bit of excess ortho cement on there tooth, it’s not the end of the world, right. And essentially, even with this onlay if there’s a tiny bit of excess composite at that margin, it’s composite, which we use for restorations if it’s smooth, I’d rather leave a couple of microns of excess composite. And if it stains over the years, I can use a brownie or a polisher and polish it back. We have this obsession with getting absolute flushed to the tooth. And it was bioclear that really turned my head around saying anything adhesive doesn’t like a margin. So we’ve got to get our things out of our head about having a finish line. It’s got to be an infinity bevel. So I always air abrade past my margin, because I don’t want flush, I want bond, I want a true bond to that residual enamel. I don’t want flush I’m having to pick off. It’s a different, whole different concept. But to me, it makes so much sense.

[Jaz]
Brilliant, chamfer versus bevel? Which do you choose? When? For example, when you’re doing the onlay? Are you finishing with like a shoulder chamfer? Or more just like a bevel? Or do you do vary between the two? Or obviously a butt joint sometimes as well, can you just throw that in there?

[Nik]
Yeah, I’m looking forward to when we’re doing a hands on course, because we’ve had some really cool type of dogs made that make this really clear, because I’ve tried to explain it a few times without pictures, and it’s tricky. I’ll give it a go. But essentially, the tooth has a point of maximum bulbosity, the widest point, and they call colloquially referred to as the equator. So the equator of the tooth is a very important point because coronal to the equator, you have an abundance of enamel, two millimeters thick enamel in all planes. Beautifully aesthetic, rock solid stiffness, that’s the key, aesthetic and stiffness. Apical to the equator, you lose enamel rapidly, and you end up with very, very thin enamel and rapidly as soon as you touch it with a bur you’re in dentine. So now you have a more flexible material, and you don’t have that residual stiffness that you’d have from your enamel. So this is why your margin has to change according to where you are on a tooth. If you are coronal to the equator, then you don’t need a big shoulder. You don’t need that millimeter of ceramic that we were taught schulenberg incredible traditional crown and bridge prosthetics. All you need is some form of what we call a contact lens margin, something that used almost like a rugby shaped diamond to create a gradual contact lens purely for an aesthetic advantage. But also like we do on anterior teeth you create this adhesive advantage because you expose not hundreds but thousands of enamel micro prisms. So we optimize an aesthetic and an adhesive advantage with a contact lens margin. If we now roll back, if we’re doing a contact area like a mesial aspect, anytime you’re breaking a contact, you’re going to be below the equator because by definition, a contact point is going to be the widest area right? So apical to that, if I’m going to have a more flexible dentine, as Pascal Magne shows us we need to replace the stiffness of the tooth. So if you have these knife edge finishes in lithium disilicate, which I’ve done, you can see chipping. And I again tried to be minimally invasive in the past showing ultra featheredge margins down in deep areas. And I’ve seen chipping in numerous cases. And I didn’t know whether it was my protocol. But now having read and understood a bit more on my journey of which I still consider myself young in that journey. And it makes total sense that patience is biting down, chewing in and out and what takes the force is the rest of the tooth near the cervical area but has taken that Brunt. And if you’ve got a flexible material and a thin ceramic edge, it’s going to fracture. So a buccal to that equator, we got to have a thicker shoulder, a traditional shoulder that’s going to be about one millimeter thickness and Marco Veneziani describes this really nicely as well to replace that stiffness on the tooth and then all you do is take a round ended tapered diamond bur and you just connect the dots. So you’d do your contact lens margin buccal lingual wall, your shoulder margin, medial distal, and then you just roll up the walls and allow the two to meet. And you have this lovely graduation from shoulder to contact lens. And again I’m making gestures with my hands which looks silly for those of you listening on Spotify or whatever. I’m making Mexican wave type gestures but eventually on the course we had these typodont made where we have a colored onlay like a blue or gold onlay cemented on an ideal prep. So the delegates get to prep through that colored onlay till they get back to the ideal prep. So it’s gonna help them visualize where we want what and why? Because I’m a very visual person. And so I’m a typical Essex boy, I need things explained in the most simple way possible. And if I can get it, anyone can get it.

[Jaz]
Dude you explain that so beautifully and do send me details of the course. Because you know, what usually happens is someone that’s passionate you do comes on. And people always bombard me that, hey, you know what, Nik was awesome. I want to learn more about onlays from him. So I’ll rub, just take it on the website, it’d be easy to find. So I will add that to the show notes because those models sound amazing. And I think you guys were the FIPO protocol, what I seen a really got something great going there as well. Now we can really nicely touch on, because you’ve explained that beautifully about what type of finish to have where and it makes so much more sense in relation to the equator, which is just a genius term. How can we make our content lens margins or any margin that we’re finishing mid buccally? Because we want to be more conservative. How can we really get to blend in without having that, that show through, that visible differentiation between the restoration and the tooth, like, sometimes I’ve got haven’t I’ve had an aesthetically demanding patient on a premolar, for example. And for someone who’s not aesthetically demanding, I’m happy to finish mid buccal alright? With my lithium disilicate. With someone who’s aesthetically demanding, I turned it more into a Vonlay like a veneer onlays, that buccal, I’m gonna drop it right down.,sacrifice that enamel for the aesthetic advantage. Only because I’ve doubted my skill to be able to nail it in that high demanding patient. Any gems you can share with me?

[Nik]
Well, Jaz, you being harsh, Didier Dietschi, he himself says that the ideal place to have a finish is either in the incisal third, where it’s all enamel, or the cervical third where it’s all dentine, the user, the operator should be very careful about placing a margin in the mid third, where it’s a combination of both, especially if it’s visible in the smile zone. So this is the master of bonding himself saying this so it’s not like anyone’s doing anything wrong by dropping the margin more apically. So the first tip I’d give, sit the patient up before you numb them up, smile and mark the extent of the tooth that you see. I use just I’ve got a hundreds of black markers I just buy from Amazon, I just mark the line on the tooth. And when I’m then preparing if I’m anywhere near that black line, I’m going to extend it apically. So if I’m not in the incisal third, if I’m getting close to somebody is going to be seen, if in any doubt, I do exactly what you do this I like where you call it a vonlay. I’m going to I’m going to nick that, that’s great. And so then I’m with you totally because it’s risky. If it’s a lower molar in a patient that’s not as aesthetically demanding, then I’m going to push it and go mid buccal. There are some cases where I feel like No, you know what I trust even my lab technician and Steve Campbell, I’m going to go for it. And we do get really nice results. And the way to do that is number one, not have a flat tabletop, if you have a flat tabletop, you’ve got what we said earlier, you’ve got a finish line composite doesn’t like finish line. If you’ve got this contact lens, that is the same principle as our class four, you’ve got this margin of error with this bevel effects. The second thing is the translucency of the ingot that you use, because if you’re using a opaque ingot, no matter what you do, it’s gonna look so different to the tooth underneath. So you’ve got to start looking with products like LiSi, you want to look at the high translucency blocks. Because they are, they are like a contact lens. This whole process is like a contact lens. So they absorb the color very well from the tooth underneath. And then you submit with just a normal A2, A3 composite, we use the posterior A3 composite or whatever the tooth is on that on and it picks up the color beautifully. The only caveat being is if there’s any residual staining on the tooth and you haven’t blocked it, it’s gonna look rough and it will show through even if it’s on the occlusal it will still affect the color from the buccal aspect. And I’ve had a couple of cases that I really regret where the there was heavy occlusal staining and I didn’t put enough of the baseliner. I thought it’s okay, but buccal was fine. It totally showed through. It’s amazing. It really does flourish through that too. And then the other thing is using composite rather than luting cements. The composites are designed to be strong, but the composite is designed to be beautifully aesthetic with the optical properties they have the filler particles, they’re designed for that so why are we still messing around with luting cements I don’t get it. We’ve got a material that is designed to blend, heat it and that’s the key thing for me and that’s been a game changer, but in an aesthetic demanding patient. And with the 100% you got to, don’t make your job harder than it is.

[Jaz]
Well said and I think anyone who’s sitting on the fence who has been not confident in changing their protocol from a dual cured cement like Panavia, which I am a big fan of then moving to a composite, I think your protocol today and how you described it is really going to get a lot of confidence to move on to that and your your tip about heating the onlay is fantastic. Just a point about Emax in particular. So lithium disilicate Emax five, that’s the one I’ve used more of, I tend to go for like an LT, or low translucency or an MT, medium translucency ingot is one better than the other for trying to blend in your experience?

[Nik]
Well, the more translucent so low translucency is going to be difficult, because you’re going to have that obvious change. Because it’s low translucency and medium will be better. The high translucency are the ones that are going to blend in the best for sure. But the color of the tooth underneath has got to be good. If you’re doing one of Vonlays, you’ve now coined it, I like that, and you’ve got a dark tooth, let’s say non vital, then you don’t want to be using our high translucency block, then you can go for a low translucency block, it doesn’t matter because you’re in the cervical area anyway. And you’re finishing on the an area which is mainly denting which is more chromatic and easier for that lab to mask. So I think it comes down to operator technique of how we’re finishing that margin. It comes down to documentation with our photography, our labs are not magicians, and I feel sorry for them. They give a, they’re the hardest job. They don’t have the emotional glory that we get when something goes great. But they get all the when something goes wrong.

[Jaz]
It’s totally cool on this podcast, man, I love that. I’ve got I’ve got some technicians who listen to this actually. And they’re gonna love that. So shout out to Graham from truform lab is a buddy I’ve met and met on Instagram and we chat quite a bit now. Quite a few technicians picked up so they wil love that they will really appreciate what you said.

[Nik]
Oh man. And listen. I say to young dentists, if you want to learn how to prep a tooth, talk to your technician, people just don’t do a [inaudible]. People don’t talk to their sales representatives who are trained to know the best protocol for the product you’re using. And people don’t talk to the lab technicians who are making prep your onlays on your preps. Now get their advice. Let them you know critique I always say even now I say to either forced to I use for my high end cases, I’d say to either let me know if we’re struggling or something and what I can tweak next time. And there’s always something, there’s always something. To this day, every time I think I’ve nailed it, I’ll look at my postdoc photos and think close but now I’ve got to work on this. But essentially, communication with lab is very important. You need to have a lab that has got the gusto, the skills that can do it. So I’m not saying the dentist should blame themselves for everything. The lab also has to be damn good. And you need that marriage of harmony between you, find someone that you work well with. And if you’re dentist who’s trying to find a lab that’s going to do a lithium disilicate onlay for 20 quid, you’re not really going to have that quality. I mean, do you want to charge 20 quid for doing onlay? What do you expect if you’re getting charged 20 quid for the ceramic, right? I mean, even certainly not cheap. But I charge accordingly for it to the patient. But the time he spends that bespoke character we get from it the little craze lines he puts in, the white effects and you just put it on you think, Oh man, it’s just music. It’s beautiful. When you somebody wants to go on. That’s the key. I think she’s done. Amazing.

[Jaz]
That is also I love it. And this moves us on to the last big theme of this podcast, were reaching that critical one hour point, right? But this is so so so so big, right? Onlays, we’re doing more and more onlays, I feel that dentists are doing it more and those dentists who aren’t doing it, then they have an opportunity to learn from people like you, elevate FIPO, to learn how to do these preps to get because a lot of dentists don’t have faith. They don’t have the faith in bonding because they start to traditional methods. And they need to move and learn about the protocols. So, that you’ve done so beautifully described today. But one thing that annoys everyone is temporary. So when you’re doing the onlays that’s more in the direction of a tabletop, let’s say, it doesn’t have to be but even then, you know, compared to a traditional crown, you don’t have that retention form, right? You can have a little bit resistance. We don’t have that classic retention form because that’s coming from your composite, that’s coming from your Panavia or whatever you’re using. It’s coming from your etched enamel. So therefore, the risk of the temporary coming away is much higher. So what are Nik Sethi’s top tips to temporize onlays?

[Nik]
Well, first thing I say is it’s not as fun as with a traditional crown. I mean, I did Basil’s year course and he really I opened my eyes to how to do provisional properly on a traditional prep. And I love realigning with acrylic, and I love nailing my provisionals for full crowns or verti prep crowns, it’s stunning. I really enjoyed watching the tissues mature. With onlays, Listen, you’re saving so much tooth structure, there’s got to be a weak link in this chain. And the weak link is the temporary here. I’ve got some tips do I have all the answers? No. But what I will say is two things. Number one, if you’re working with a lab that can turn around work quite quick that even if the onlay attempt does come off, because you’ve done immediate dentin sealing and a mini core, there is no sensitivity. I’ve never had a patient that said to me, Well, no, that’s a lie, I’ve had one. But hardly ever do we get a patient that has sensitivity if the onlay comes off, and it’s a matter of a week or two and they’re back. I’m not saying that’s a great situation. But if it does happen, it’s not the end of the world. However, we have come up with a couple of little things that have dramatically helped. But one thing I don’t like to do, which I know some people do, some people like to spot etch and just bond the provisional on like we do for veneers. I find that risky because after I’ve done my immediate dentin sealing and my mani core, even if I’ve used an air block, I’ve had situations where my provisional has bonded and I couldn’t get it off. And then I’ve had to prep through and we start again, that’s no fun for anyone. With veneers, it’s different, you got a lot more leverage. And it’s not the same, your preparation even more smaller. But when you’re doing an MOD with an onlay you’re in trouble because it will lock into that MOD area. So I don’t like to shrink fit them as such. I’m not a fan of that, because it can bomb underneath. And also with shrink fitting, you often get access, you know, you can put wedges in to reduce that. But you know, you’re relying on precision gums at visit two and you’ve got inflamed gums and you’re trying to isolate this thing. That’s not fun. So I am doing a traditional putty index before. But here’s the key thing. I’m trying to improve that patient all the time. So if I’ve got a deficient, lower right six occlusal amalgam when the walls have cracked, a lot of the reasons why that would have happened is because the dentist infra occluded, which I probably did a few years back infraocclude that amalgam, the residual cuspal walls take a lot more pressure, they end up fracturing, right so before we start prepping a tooth, what I like to do is look at the opposing tooth and see how’s that tooth over erupted. Do I need to reduce that palatal cusp? Riaz came up with a great idea for the FIPO concept where we put a blob of composite on the tooth but some glycerin on the opposing tooth get the patient to bite together and we cure it. We take a scan of that because that shows the lack of perfect inclines that they need because it is a negative of the opposing cusp. And what I would then do is I would then take an index of that after I shaped it up. So my temporaries already gonna have a better occlusal function and what they came in with so we’re getting better every time. Once I’ve then made my using a bis-acry or just to make my temporary onlay..

[Jaz]
So there’s this thing Bis-acry is like protemp or integrity that kind of stuff?

[Nik]
Exactly. Luxatemp, Protemp you name it. We put a bit of glycerin over the surface. I try not to use Vaseline because Vaseline doesn’t come off and it will interfere with your temporary cement. So I use a bit of glycerin I then use my Bis-acryl. I let the material set for a good three, four minutes you know trying to just pick it off after a minute is still too flexible and the shape will shrink while you’re adjusting it and it won’t fit so well. Then once I’ve adjusted it and I’m happy I don’t use Temp-Bond non eugenol i think is useless. I think it’s rubbish. It’s one of the worst materials I’ve ever used, the Temp-Bond is great if I know I’m going to be using glass ionomer cement then Temp-Bond is great but Temp-Bond non eugenol I slightly mixed Vaseline and on purpose just to piss us off. But sorry whoever makes Temp-Bond, no offense. But essentially I like to use Poly-F i find that it’s much more attentive to the tooth. It’s bactericidal, the gums come back looking beautiful. And if it’s very non retentive and I’ve got someone with bruxist features or parafunction, I will just get a bit of acrylic like tab 2000 or get a coe-pak, the acrylic..

[Jaz]
[Jaz] Trim?

[Nik]
Trim. I think you know, you just mix a tiny bit of a trim. You put a bit of monomer on the bit of, sorry, bit of bond, a universal bond on the adjacent teeth, and you just mix a tiny bit of trim, and you put it on the onlay and lock it into the tooth next door just under the equator, you make sure you’ve got space for the TPN. So also…

[Jaz]
That’s so Basil.

[Nik]
Yeah, that’s, you know where I got that from, right? So you’re just tacking it in with a bit of Trim, so that you’ve got that physical protection. It’s not bulletproof, but it was personally reduce the risk.

[Jaz]
That’s really good. I did appreciate it and it makes sense. I did appreciate that you can, because I make my temporaries also out of Bis-Acryl. But for some reason, I don’t do it, what you’ve suggested, because I just always thought I had to use acrylic to do that. But you’re so right, these modern, seventh generation, whichever generation we’re on now, with [inudible] and stuff, the acrylic can bond to that and you can tack them in. So you’re completely right, we’re reminded.

[Nik]
Just like we can re face Bis-Acryl immediately with flowable. Right? Or composite. It’s the same thing. It’s got a resin base to methacrylate resin maybe with a resin base. So you can apply the Trim before you started, you know, glazing or polishing, you still want to rough this Bis-Acryl surface there, lock it in. And it works really well. It’s, it is a I would say it’s an improvement on the amount of decementing that we have. But I do say to my patients, I show them the prep I’ve done and I showed them a prep I had done in the past on a full crown prep and I still do a full crown preps you know, discolored teeth, parafunctions. I haven’t checked Schilling Berg’s textbook in the bin By the way, I’ve got massive respect for Basil and people are doing traditional preps, I still do my other things are currently as a lot. But more often than not, we’re trying to veer away. And for those kinds of cases say to my patient, okay, the worst thing that’s going to happen here is your temporary may come off, but it’s unlikely to be sensitive. And we’ll see quite quick to get this turned around. But biologically, we’ve saved a tremendous amount. We look at the studies by Sorenson [inaudible name] And we look at Saunders and look at the rate of tissue, the amount of volume you lose with a full crown prep 60%, roughly, and you look at the loss of vitality around 20% with full crowns. Whereas with onlays like this, it’s no different to doing DO composite.

[Jaz]
Brilliant and two observations, I think I’d say is a with the zinc oxide cement that we or polyethylene or that we use as a temporary cement because I also do that i think that’s another reason why patients don’t get sensitivity is because if the onlay was to come away, it leaves that thick white cement layer which is just brilliant for preventing sensitivity again, and obviously a good ultrasonic scaler can just you know frazzle that way.

[Nik]
Absolutely picks off really nicely low power, and just be patient, and far too, or trying to, you know, be aggressive, but ultrasonic works by the power of the ultrasonic breaking down the surface, not the pressure of your tip. So, you know, I see young dentist, remember training them and they digging on that tooth and I’ll say, you know, chill. Turn the power down, take your time, find that little edge and just work on it. And then suddenly, a whole sheet just pings off. And it’s just being a bit more patient, I guess.

[Jaz]
Brilliant and a real pearl I took from you as well as to use the trim and put it in the side onto your Bis-Acryl using a latest generation bond material. That’s, great. And that’s better than some ways I’ve tried it in the past whereby you can etch the buccal and the palatal. And then you sort of put a blob of flowable in a little bit on the enamel, leave on a Bis-Acryl. But it’s annoying, who wants composite on their buccal and the palatal? It’s annoying. It’s fiddly. Yes, it can be effective, sometimes not so much. But I think everything you covered in terms of the very beginning looking at the occlusal shape and the way that the opposing tooth will guide and excurse with it. To use it with cement use and these little accessory techniques, it’s just been absolutely fantastic. Any other points or I think you’ve covered that comprehensive [inaudible] [Nik]
I know, I mean, I’m really excited about doing the kind of courses and stuff we’re doing as Riaz as next year. Riaz blow my mind with occlusion, my understanding is picking up very, very quickly on that. And the preparation kind of protocols. I hope we’ve made it quite simple. But in terms of bits of guidance, you know that the type of dentistry we’re talking about, you really can’t do unless you’re using magnification. So I mean, all these kind of subtle contact lens margin, equators put that all in the bin if you’re not using magnification, so I tell any young dentists, go and get a good pair of loupes. And don’t start off with 1.8 and build yourself up, jump in and get a decent magnification get us get a powerful light. And, you know that’s the only way we’re going to start to ever see the type of modern adhesive dentistry, that the loupes, a micro etcher and, you know, in terms of protocols, it’s lovely talking about how we can blend in a margin but understand the bonding agent you use, go look in the drawer rather than say, nurse, give me the bonding agent. Have a look what it is. Is it a self etch? Is it a total etch? Have a look at the manufacturer’s instructions. You know, we somehow just like kinder eggs we become kids when we start using these things. I don’t need the instructions. Give it to me. You know, these things are there for a reason. Pick up the instructions. I’m not going to tell you which bond to use, but use whatever bond you’re using to the best capability that it cannot be and light cure, get a radiometer which of cheapest chips from eBay and measure the power. Is it 800 milliwatts per millimeter squared? What’s the wavelength range? You know, traditionally we know that composite has a photoinitiator camphorquinone which is set for 50 to 490 nanometers is activated to that. Camphorquinone is very yellow. So a lot of composites, you talking about blending in margins, and class four composites or posterior composites. The older ones used to go for a yellow one of the reasons is because of the camphorquinone, so in a response to try and reduce that they use different initiators now, for phenol P, all these other things, but they don’t activate at the same wavelength. Some of them activate a 400 nanometers, some of them activate 500 nanometers. So if you’re using an LED light curing, unlike the old halogen lights, the Optilux 501, a halogen light has a very wide wavelength range, and led as a very narrow wavelength range. So if you’re using a single LED light that’s catered for camphorquinone, which is 450 to 490, but you’re using a composite that has accessory initiators, you could be following the instruction and cure for 20 seconds, but you’re not giving light have the right energy to activate that initiator. So you need to make sure using a latest generation multi LED light, you can use the Valo, there’s a liight cure from GC, that translex 2 again, there’s loads of great lights out there. But it’s got to be more than 100 milliwatts. It’s got to be multi LED. And you’ve got to look at the beam distribution, it can’t just have a focus hotspot in the middle and then very, very weak on the sides. I know we’re getting a bit off topic here. But essentially, this is more important than blending in of a margin. Because if we don’t appreciate that bit, it’s going to get — in four years anyway. So what’s the point?

[Jaz]
Amen, brother, dude, I love your science. I love your passion. I love your geekiness man, I’ve actually forgot how geeky you are, Nik, there’s been a brilliant amount of but in a good way. We love Geeking this one and this is what this podcast all about. So Nik, honestly, you must send me any brochures, any websites you have for the course because people can definitely message saying where can I find them? So I’ll stick them on the show notes for this. This has been up there with probably at the level of Chris Orr and Prof. Paul Tipton as to the you know one of my clinical heavy and I mean that in a good way because we’d like these now and again these these heavy ones that Yeah, yes, you’ve got the the ones that we talked about like we’d Rajiv Ruwala, 10 successful habits of dentists, which is so much fun. But when you get this really geeky one, these ones I love with you, Nik, we’re just now it was so full of workloads at every stage, I was visualizing exactly what you’re doing the restoration, exactly what I’m doing what we’re doing for tooth. So I know we’re gonna get loads of like, applause and messages just saying wow. Nik’s protocols we’re on fire. So Nik, thank you so so much for giving your time this evening. I know you’re such a busy guy.

[Nik]
It’s no not at all, mate. You’re super busy. But thank you. It’s been a real pleasure. And I’ve been looking forward to doing this for a while actually I was quite nervous about coming on air with you. You’re like a celebrity in the dental world now. Thank you.

Jaz’s Outro: Guys, What did I tell you? I told you what infratry and certainly there were so many knowledge bombs in there. It was phenomenal. Nik, thanks so much for doing a wonderful job. Guys, Thanks so much for listening all the way to the end. If you liked it, share it with someone who might be placing their first onlay or maybe their 100th onlay. And they might just gain something from the temporisation or from the bonding protocol that they can use on Monday morning. So thank you so much. I’ll catch you Same time. Same place. Next week.