A daily dilemma in Dentistry is deciding when (and HOW) to restore that extensive MODL amalgam restoration that was placed over 30 years ago! We go deep in to this, looking at single-tooth factors but also a full mouth ‘bigger picture’ view with Dr Andrew Chandrapal who has been trained by world-class clinicians including Dr John Kois and Dr Didier Dietschi,
Protrusive Dental Pearl: How to make sure your equipment doesn’t keep getting lost? Use color coded tapes on your own equipment and tell your team that stuff is super important because it belongs to you.
“Using things like air abrasion to then try and remove the apical amalgam whatever you can do to try and be gentle in your removal of that material is a good way to go” – Dr Andrew
In this episode I ask Dr Andrew Chandrapal,
- When to classify the large restoration has failed (12:45)
- Risk factors of a tooth with large restoration would undergo necrosis (18:33)
- About restricted anterior restriction or constriction (22:21)
- How to prevent yellow stains and if you should intervene for a long time restorations? (29:16)
- Little tip on special burs to use when cutting out caries (31:21)
- Cutoff point whether to cap the cusp tip or not (33:26)
- When to decide if you should intervene because of marginal staining and communicating to patients (37:44)
- What factors to consider moving from direct restoration to indirect restoration? (39:59)
- Treatment plan to reduce the risks of fracture (42:31)
As promised in the episode, if you want to learn more of Composite courses by Dr Andrew Chandrapal – IndigoDent Education
If you enjoy this episode, check out this Composite vs Ceramic with Dr Chris Orr
Click below for full episode transcript:Opening Snippet: I've shied away many times I've made a treatment plan for a patient for quadrant but I will just work around that upper first molar we've got that behemoth amalgam because I don't want to touch it. Any help you can give me? We should not be responsible for owning the clinical problems that the patient presents with...
Jaz’s Introduction: Most of my patients are above the age of 60 actually nowadays and when I look into their mouths I see these huge amalgam restorations you know like it’s MODB they’ve got very very thin cusps you can see the amalgam shining through. You can see craze lines, crack lines but they’ve been there for so many years, they’ve been there for two three sometimes even four decades i mean you look at these studies about longevity of amalgam and composite and you know my patients are the heavy metal generation patients are a living testament to longevity of amalgam however when things go wrong they can go catastrophically wrong like remember when you find secondary caries around amalgam it can be a huge huge mess and of course, we know that in time cusps can fracture around amalgams and that’s like the most common emergency we find which is when someone just broken off a cusp and lo and behold there’s a huge amalgam left behind.
So when should you look at amalgam and say you know what I’m gonna decide now is a good time to crown this tooth or now is a good time to remove this amalgam because I worry about secondary caries or I worry about microleakage because if they’ve been like this for 30 years 40 years and I can’t really justify enough a good reason to drill into it then why am I drilling into it okay? This kind of debate that I have with myself. So to help answer this as part of this back-to-basics series for August, I’ve got Dr. Andrew Chandrapal from the UK, who is just such a gifted clinician.
He’s well known throughout the world actually and I think he’s done a really good job of covering these basics of you know when do I need to remove the stained composite like is that staining around a margin, how can we prevent it but then when it happens, do we need to actually drill into it or not? So we covered that kind of thing but also we talk about that patient who’s got these amalgams everywhere, these flat amalgams that they’ve accumulated over the time and how we need to manage those patients but an interesting thing that Dr. Andrew Chandrapal discussed which I’m going to share with you now as like a teaser for the rest of the episode is these patients who have a flat amalgam like you know they go from having beautiful cuspal inclines to having this flat amalgam thumb inside the cavity right and then they have another one and then they have another one, they have another one, eventually because you’re losing the anatomy and the dentist obviously because it’s flat it’s very unlikely that that restoration is finely tuned into the occlusion. So what you get is that every time a restoration is placed it’s out of the occlusion right? So slowly but surely you’re losing occlusal vertical dimension just imagine all your molars getting these flat amalgams and eventually each one is out of occlusion and eventually you lose vertical dimension and it’s interesting how Andrew Chandrapal, who’s been very influenced by John Kois talks about this constricted envelope that can form, now if you don’t understand what that means don’t worry Dr. Andrew Chandrapal will cover that.
So yes this is back to basics theories but some of it does get a little bit into the bigger picture which is good we need to appreciate we need to look beyond the single tooth and appreciate the bigger picture. So much to look forward to in the rest of this episode I hope you stick around also for the rest of August for the back-to-basics series. I’m hoping if you’re watching on youtube or dentinal tubules or whatever I hope you like my new setup I’m standing no longer seated I’ve got my biggest green screen mounted behind me so I hope it’s coming out okay.
For those of you listening I appreciate you while you’re running, jogging, chopping, onions, or gardening whatever you’re doing right now thanks so much for joining us today. If you’re a new listener to the Protrusive Dental Podcast, Oh my gosh, welcome thank you so much for joining us and sticking around. Check out some of the old episodes and just before we join the main meat and potatoes of the episode I’ve got my Protrusive dental pearl for you. So Raghav Munjal recently on the Protrusive dental community Facebook group. That’s facebook.com/groups/protrusive. He asked an interesting question he said ‘Jaz, you posted a while ago on Instagram about color coding your burs or dentists that buy their, or associates that buy their own equipment and how to make sure it doesn’t keep getting lost? Like that’s a huge bug bear of mine you know you spend your hard-earned money on buying this equipment or these burs or this you know composite brush or whatever modeling resin right and then it gets lost misplaced broken whatever it’s really you know it’s really sad because there are these associates who are buying their own equipment that they’re growing but they’re few and far between i think it’s a great thing to be able to buy your own stuff sometimes to elevate your dentistry and then hopefully find a principal that appreciates you enough to buy you the stuff that you want to use but anyway when you do, when you are that associate and you are buying that stuff one way I found to make sure that things don’t keep getting lost is to color code that equipment now obviously you can’t color code your mirrors because that’d be difficult but you can color code the cassettes that they go into or let’s talk about I’ve got like this little sword this interproximal saw is if I’ve ever bonded composite on the adjacent teeth together so I’ve stuck the two teeth together i will use that this little saw that itself could be a Protrusive Dental Pearl actually. Anyway use this saw but that little saw has got a handle which i’ve got like this yellow and green tape so what I’ll do is if you go to protrusive.co.uk and if you click on this episode then I will put a link there to the instagram live i did showing you exactly the tape that my nurse uses so i know that if something is color-coded orange and green and everyone knows that that belongs to me okay it always comes back to my surgery. I’ve got some handpieces that are color-coded orange and green so I know that hey these are Jaz’s handpieces they’re going to go back to him and when it comes to burs, this is the most annoying thing the easiest thing to lose is burs right? So why did i buy my own bur blocks from like eBay or something right and the color they could they’re colorful but I also color-code them with the green and orange banding which again like I said if you check out the website i’ll show you exactly where I get that from and then the bur blocks themselves are color-coded so any burs are put in will always come back because they’re part of that block and you take a photo of that block.
So the decon nurse knows what which burs are supposed to be inside that block so essentially the pearl is to start getting a little bit savvy with your equipment look after your equipment and part of that is actually color-coding it but also telling your team that hey this stuff is super important because it belongs to you. So hope you hopefully we can elaborate more on the website when you check out the full Instagram live I did some months ago. Raggy, thanks so much for asking that question on the Protrusive Dental Community and let’s finally join Andrew Chandrapal on what’s a very interesting episode about the very fundamental question of when should i drill this amalgam?
Main Interview:[Jaz] Andrew Chandrapal, welcome to the Protrusive Dental Podcast, my friend. How are you? [Andrew] I’m doing really well, thanks Jaz. Thanks for having me on here. [Jaz] It is amazing to have you on finally it’s something that people have been asking for. Mohammed Sharjeel asked for you. Loads of the others of the Protruserati have asked you because obviously we’ve been infected by your enthusiasm in the past. I first saw your lecture at the BACD, you did a little workshop with a microscope and you’re teaching us how to do these beautiful life-like composites and I saw you again lecture this is like one of those evening things in the BACD again this is at the BDA on behalf of the BACD and honestly your work is always inspiring. So it’s great to have you on to, really I’m gonna try and suck as much knowledge out of you and share it with everyone as possible today. [Andrew] Yeah go for it I mean it’s very complimentary what you have to say I mean it’s just you know it’s one of those things that I’m very lucky to be in the position that I’m in. I’m thankful to people who see you know what I can do.What i can offer to the profession and those who believe in me. So I’m privileged to be here. [Jaz] And to just give us a little bit about your journey because I think you qualify from Birmingham right? [Andrew] Yeah, I’m a Birmingham graduate. I qualified 2001. I took a year out and concentrated on trying to focus on what I did as an undergrad doing music and stuff like that because I was a bit of a performer back in the day and yeah so I qualified in 2001. I worked in West Bromwich in the black country for a couple of years developed the accents they thought would be time to leave. Moved down to oxford to mix practice there and then joined a pretty well-known and high-end private practice in Banbury and then basically moved to Buckinghamshire which is where I have been ever since. I’ve been there for 16 years now so I spend my time there and teaching as a do-all over the place and then also in specialist practices in Central London now. [Jaz] Who inspires you? Who inspires Andy? [Andrew] Oh, that’s a good one. So I guess there’s kind of mind, body, soul inspiration. So I guess the first inspiration I can’t lie it’s got to be my dad who’s not with us anymore but he was a massive inspiration to me we quite alike both grafters, both trying to do our best to be people, persons, as it were. The next one is a guy who taught me as an undergrad. His name is John Davenport, an amazing guy and one of the first things he said to me said ‘Andy, you want to make sure that whatever you do professionally because I can see that you’re quite focused on your profession always have a sideline, always make sure you do some stuff on the side to give you a complete separation from dentistry otherwise it will have this ability to kind of suck you in a little bit’ and with that, there’s a local park in Birmingham that I was going through that weekend and I saw him bear in mind John Davenport that time was probably in his mid-60s and I saw him rollerblading just like rollerblading across the park i’m like wow this guy’s for real. So yeah, he was probably the mind-body-soul mentor and then clinically I guess the first time I met Pascal Magne was in 2006 and he changed the way I performed dentistry. He’s been massively influential for many many dentists and I know you know him and know of him well and then John Kois, who’s been my mentor in sort of restorative dentistry I suppose since about 2008. [Jaz] You’ve been to Seattle a few times to see him in the course program? [Andrew] I have. I’m a graduate of the course center having done all nine modules and i teach the principles on some of my courses so I fully buy into his approach. It’s not a philosophy so it’s not like ‘oh yeah you know I do things that Pankey or the Dawson way or anything like that.’ It’s based on metric science and he manages to weed out all the rubbish and keep the good stuff within the science over the last 50 years and so I love that philosophy and so he’s camper fear and thought is always changing and modifying so I find that makes sense in my little head. So i love that and then finally Didier Dietschi is a great friend and mentor in Geneva.
He has supported me throughout my career to this point and he’s a wonderful clinician and an even better person he’s that type of person that i strive to try and base myself on professionally and you know and have the integrity that he does. So those are my people. [Jaz] You have some amazing mentors and friends wow that is so inspirational. That is just so good I love it. Well today, we’ll be talking a little bit about we’re going back to basics so august is all about back to basics and I could have picked anything because I know you do teaching on all varieties within dentistry, beautiful composite restorations, the management of tooth wear, and everything in between and wide all that but the main thing that Mohammed Sharjeel, who just specifically i don’t know why he thought of you but he said ‘Look I want to learn this topic and I want to learn it specifically from Andrew Chandrapal. I said okay go what is it and he said I want to learn about the management of our day-to-day patients who like my patient base is average patients about 60 years old plus and they have these huge amalgams, right? And he just wants to hear from you and he wants me to bring you on an interview and ask you questions about how do you manage these big restorations and when they have subjectively failed because we do see a lot on social media and we’re in a blessed position as young dentists who want to learn that nowadays. You couldn’t do this maybe 10 years ago where you can just go on and look and observe and learn from full protocol cases and there’s so much to learn but there’s also something you appreciate that this some things that you would do or some things you wouldn’t do other clinicians are doing or not doing.
So the classic example is you know that restoration that you would have never touched or replaced and other dentists are replacing that’s the classic thing so essentially though I’m beating around the bush one of the first crux of a question I’m getting to for you, Andy is these patients with these large restorations, when do you classify them as failed and when do you have that what’s going through your mind when you’re discussing about okay has it near the end of the restorative cycle?[Andrew] Okay, great question. Thank you, Muhammad. I think let’s take a step back from this Jaz for a moment, and if you look at the whole sort of dentition in a single individual for a moment and you look at someone who’s in the age group that you said that is typical for my kind of age group in general practice as well you’re looking at someone that typically has gone through a restorative cycle of dentistry that means that there was perhaps a little bit more heavy-handedness for intervention in the areas that have gone before us.
So let’s look at perhaps the 70s the 80s or maybe the early 90s typically these people would be pretty heavily restored and to give testament to the practitioners of that time they were doing amalgam restorations bonded or pinned that I could never do. I have no idea how these massive MODL amalgam restorations have stayed in place for 20-plus years because i simply could not do that and so there is a degree of kudos to them to practitioners, before we start to then change the rhetoric a little bit but what I will say is that when you have a patient that has a mouth full of these there is a cycle that’s gone before them and this sort of cyclic fatigue, to me is the bigger picture so if we go back to Edwina Kidd publications and her textbook she was then referring to the fact that amalgam restoration that is unleashed or ditched to the degree of perhaps 0.5 of a millimeter or more should be then be replaced because you’re going to get that sort of creep of material over time which is going to then plaque trap and bacteria et cetera. So that’s one indication but that’s fairly historical. What I’ll say is this if I’m looking at a large restoration that’s got facet marks in it or has got a wide occlusal footprint as I call it you know so in other words something that shows you that occlusal contact is wide and flat. One then the potential for that to be adding especially when you have multiple restorations of that nature the potential for having loss of posterior guidance, loss of point contacts, loss of posterior bilateral simultaneous contacts is quite high, and what that will do… [Jaz] As what you mean is if you intervene in that scenario then the risk is high? [Andrew] Well, what i’m saying is that if the risk is high if we let some of these things go. So the point is of intervening on a single restoration like that is that you have to then conform to that occlusal scheme and the difficulty with that is you’re adding to the problem. So this kind of cyclic restoration cycle means that every time a restoration like that wears or every time a restoration is flattened in that sort of way you lose a little bit of vertical dimension and that cyclic that’s typical phase means that you lose vertical and then you increase anterior guidance and increase anterior contact, in other words, get to a point of anterior constrictions being a much higher risk than they would usually be and that in turn might give you anterior wear as well as the posterior wear that you see so, in short, I’m sorry I’ve gone around the houses on this but my indications for replacing something like this is if i start to see fatigue early fatigue of a restoration, singular or multiple. Then I’ll have a look, I’ll step back and have a look at the dynamic and the static occlusion as a whole. If I’m suspicious that we’ve had a loss of vertical as a consequence of that, I will keep a watch on that perhaps for six months and I’ll say to the patient keep an eye on this. Let’s take a scan of your teeth, let’s take photos of your teeth, or let’s take silicon indixes and then let’s see if this problem is dynamic in other words let’s see if the tooth wear is increasing and then decide to make a pathway to then replace your worn and flattened restorations.
Now whether or not that’s amalgam whether or not that’s composite the principle is the same because whenever you’re replacing a single restoration you are having to confirm that’s the first thing. I hope that makes sense.[Jaz] It does. I’m just going to probe you further on that but I’m gonna let you finish the two-three points here saying because I’m fascinated by this and i love the angle we’re taking it but I have got some things to try and clarify for listeners about the decision making tree but please do carry on so if you’re like I said you might monitor it and see if there’s a dynamically deteriorating situation. [Andrew] Yeah, there’s the second thing is that if I see a restoration within a dentition that does show wear or high occlusal contacts or quite flat heavy occlusal contacts, I’m always going to be suspicious of fractures within the actual coronal tooth tissue itself and one of the main things that I am worried about with amalgams that have been present for a long time is what Cameron stated in 1964 and that was, there is a massive concurrence of fractures subrestoration when you remove amalgam restorations and that’s because the amalgam restoration in itself is harder than the tooth substrate by which you put it into and so that cyclic fatigue that you get on amalgam restorations the casualty is not the amalgam off and it’s the tooth and so when you unearth these seeing internal fractures, cavity fractures are for me are a real commonality and sometimes that can be a problem is that if we leave it for too long you’re then dealing with problems that could potentially be terminal for the tooth. [Jaz] But how can, you know, obviously we can’t see through the restoration I mean yeah it’s very common you and i both see we remove these big amalgams and we see this massive crack line and we take the obligatory photo so we can explain to the patient afterward our findings in case it does go necrotic or needs a root canal but yes that’s one factor but then how do you, how can you predict that or is it just a high percentage chance and you go with that in mind? [Andrew] Well, i think if we rely on the percentage chance of probability I think that we’re on shaky ground. I think that’s probably you know because I’ve got an inkling, can we do this? I’m not sure that’s going to fly and so actually what I do is I try and look at the evidence over some time I’m lucky I’ve been in the same practice for many years and so if I’m noting that tooth wear or tooth surface loss is progressive for example or this patient presents with lingual or buccal tori or they have masseter hypertrophy as an example, I’m thinking okay we’re building a case for someone who’s higher risk and what we’re trying to do here is do a risk assessment on every single patient that comes our way. We’re trying to be predictable in terms of that treatment modality. So that we don’t have a crystal ball but we can look at the risk factors that would associate with the risk to be higher in one individual than another and that in itself might legitimize the course for this individual requiring their amalgam or restoration to be removed plus a little bit of fatigue that we see on the individual tooth versus another one that doesn’t show any form of dynamic tooth surface loss, shows normal muscle tone and this type of thing.
So there are differences but you’ve got to step back from it a little bit and look at the evidence that stands before you. So the term that I was gonna point to on my first point just so you know Jaz it’s called a combination syndrome and combination syndrome is that thing where you’ve got a heavily restored patient who’s had you know most of their posterior dentition treated directly most of the time or indirectly on some other time and over that period the teeth is fatigued the restorations are fatigued and we’ve had that general loss of vertical over that period.
So every time you do an amalgam restoration or a direct composite restoration you know what it’s like if you leave it if you sculpt it in the way that you think or believe is morphologically correct the patient be like you know what I just can’t bring my teeth together on that one side, yeah it feels a bit odd. So what do you go in and you remove or you adjust as you need to and then yeah no that feels better but what you’ve done right there is conformed or even you’ve even infra occluded the restoration and you’re contributing to that combination syndrome. So done over some time repeatedly what that does is further reduces your vertical dimension and that is one of the main rationales as to why a lot of the age older restorations that happen to be an amalgam need to be replaced but you’ve got to look for the risks sights so you’ve got to stand back and look at the and risk assessment that individual patient.
Now I’m going back to the third point it’s a bit more obvious if I start to see signs of fractures underneath the amalgam restoration so a lot of the time on premolars as an example you might see the palatal wall or buccal wall hairline fractures. Some of the time on class 2 restorations that have amalgam restoration particularly upper fours you can tend to see these little hairline cracks in between the buccal cusp and the floor of the cavity. So these types of things might be rationals as to why I’d be interventionist and choose to suggest to a patient you’d remove the amalgam restoration and perhaps then choose to lay the cusps with your direct composite after that.[Jaz] That’s a clear one to see and that’s a clear one to show the patient as well. One thing I’m going to come up with again in the first time is that it’s a much bigger picture issue to convey to a patient let alone another dentist as well which you know we tend to think tooth by tooth single tooth dentistry you know you place these restorations. So when you’re having this kind of conversation in the future about the flat, how flat the tooth is, the functional risk and being able to convey that to a patient and a timely manner be able to rehabilitate them to an improved vertical dimension, less constriction anteriorly so for those maybe dental students listening if you don’t mind clarifying exactly what you mean by the restricted anterior restriction or constriction even. [Andrew] So the idea is that we can introduce interferences both posteriorly and anteriorly. Now we know when we learn about occlusion at an undergraduate level we’re talked about the fact that posterior contacts can often be a working side interference or a non-working side interference and that is often occurring when you excurse and so as a patient ruminates or masticates their food as an example or even protrudes. If you introduce an interference on the posterior teeth depending on the direction of where the mandible moves you will introduce a working side or a non-working side interference. Now as a consequence of that this is where these working side interferences or non-working side interferences need to be removed adjusted or modified appropriately. Now that can be done subtractively or additively. Now often the theory stops there but in fact, when we’re talking about interferences, the interfaces can also be anterior.
So if you can imagine the path of closure and the path of elevation of the mandible as it comes into full closure, into full maximum intercuspation. The issue sometimes is that you can have and this is well proven throughout science is that you can have a situation where the mandible elevates into position has a micro contact onto the incisor ledge of the upper incisor teeth and then shifts back as the mandible shifts and what you get there is a situation where you can get localized incisal edge wear or palatal incisal edge wear of the uppers and labial incisal edge wear of the lowers and if you think of a class two div two type situation where you have kind of frictional wear caused by teeth that are retroclined, if the mandible actually if the path of closure of the mandible which is controlled by the CNS and that’s well-proven equally apart from trauma or pathology. If that closure means that your anterior teeth interfere on that path of closure then you’re going to have an anterior interference and effectively the mandible is going to be shunted posteriorly distally and that is known as a constricted envelope of function because what you are doing is you are constricting the envelope of function which is the methodology of how the mandible elevates into its home position as we call it.[Jaz] Definitely can hear the Kois running through your veins, Andy. I love it I mean here’s an interesting debate I’m gonna throw with you that there are some of my mentors and friends who actually I wouldn’t say they don’t believe in it but they see it in a different way. Let’s just talk about that so that there is this you know restriction let’s say anteriorly or a frictional chewing pattern as is also referred to which is am I embarking on the right tree that is the same sort of philosophy?
Now some people say that actually when we’re chewing and were that the teeth generally do not slide, they don’t make that contact and then the way that some other people rationalize that accelerated wherein a class two div two is rather than it being a constricted envelope of function they say it’s a constricted envelope of parafunction i.e when that patient does parafunction because of that sort of setup that they have, all the force is transmitted and accelerates the wear anteriorly. Do you have anything in the literature or from what we know that could counter that argument in a way or is this something that we still aren’t sure about?[Andrew] So from what I have learned and from my mentor the whole definition of. parafunction kind of differs and there is a differentiation of parafunction versus a constricted envelope of function or a frictional chewing pattern. A frictional chewing pattern is not known to necessarily be a parafunctional movement.
Parafunctional movements are tending to be classified in my eyes as non-functional movements and that’s the massive difference between those two forms of wear and so the issue and if let me give you another example when orthodontics back in the day, I for one, I was a class two div one case and I have my upper fours removed what you end up doing as a consequence of that is retracting in the upper anterior labial segment but often what you can end up doing is bringing the upper and lower anterior teeth to a minimal or tenuous overjet and when you have a tenuous overjet the problem being is that you cannot change the arc of closure as that mandible elevates into position. There are only three determinants of that arc of closure there’s the CNS or your skeletal neuromuscular system this pathology or this trauma and so as a consequence of that, that doesn’t necessarily change and so if the teeth effectively get into that position or they interfere into that arc of closure that is an anterior interference.
Now the problem being is that if we are in a situation where our jaw or rather more TMJ can ascertain a position of neutrality within the condyle when our teeth are discluded. So as we are moving our jaws and not in contact if they’re in that position of neutrality all of a sudden that position of neutrality is then in discord when the teeth meet and when the anterior teeth meet, well then shunted and that therein causes or causes the incisor-edge tooth wear that we’re talking about. It’s a phenomenon that you know it is has taken I guess a lot of credence, a lot of belief I suppose in the more recent years but actually when you look back in the literature it’s been there for many many years more in Amsterdam in the 60s was talking about this as an example. Pete Dawson was talking about this for many many years as an example and so i guess that you can create an anterior constricted envelope of function by the sheer fact that vertical height can reduce thereby bringing effectively your anterior teeth closer together. It’s the same reason why when we open our vertical height the mandible postures distally it’s the same so it makes sense that when you lose vertical, the mandible can posture anteriorly rather than distally when you open it that makes sense?[Jaz] Brilliant and I think that does help to clarify those listening who’s never come across this term that’s great. Now you’ve said the three points so far was there a fourth one or can I go to the next question? [Andrew] No that’s it. That’s my rationale really. [Jaz] Perfect and I love that so much and I want to just be able to jump to the next common scenario that you might see. So I think you’ve gone way over and above what I was expecting I love that and you really and I’m so glad you converted what is a single you know it can be interpreted as a single tooth question but you know helped everyone to explain that actually, you’ve got to take a step back and look at the chewing system, look at the functional risk so all these great things you’ve introduced into this dilemma is fantastic. The next question which maybe is a bit more single tooth based is that when we see posterior composites and they have the yellow-brown stain okay that dreaded stain that you see at the margin, A) how can we prevent that any protocols and B) when these restorations have been there for some time and there’s no radiographic evidence of secondary caries is that in itself a reason to intervene? [Andrew] Great question. So i think in terms of what we’re looking at is marginal microleakage so when you start to get a breakdown of the margin of your composite restoration we are getting a reduction in the hybrid layer effectively in the adhesion between that thin part of your restoration and the underlying tooth and so there are a couple of things that are anecdotal there’s a couple of things that are scientific that I can suggest. The first thing I think I will say is that anecdotally is that rubber dam is such an important part of this, isolation in some way shape, or form to enable the tooth substrate when it’s prepped to not get hydrated to allow the tongue not to contact you know the cusps tips let’s say of your tooth before restoration is such an important thing and i think if you’re looking at a lower six or a lower seven and you’re talking about exactly what you’re talking about there which is the marginal breakdown, the chances of that being the case are slightly greater if you’re not going to be using any rubber dam isolation that’s the first thing that said no evidence in the literature would support the use of rubber dam and so it’s such a subjective thing so it’s all anecdotal but there are ways to then apply rubber dam that are simple, that are predictable, that are quick. It’s just a case of learning it as we go along and with the confidence of course.
So the second thing I would say is that your prep design is also quite important just like something like Emax is an indirect restoration. Composite doesn’t really like sharp edges so you need to make sure that you’ve got beveled edges or that you’ve got soft edges so that when you have a finished point it’s not necessarily just a butt joint equally if you’re sort of overlaying cusps you need to make sure that that cusp tip on the internal line angle isn’t sharp it’s not a butt joint it needs to be rounded. So things like that will make a big difference..[Jaz] Any before you just jump onto the next one, just a little tip that you can give us when you’re cutting your cavities removing caries, is there a special bur that you use to try and create that sort of bevel or the sort of the correct emergence out into the cavity from the proximal surface? [Andrew] Sure. So, I’m old school and so I would still tend to use steel roseheads to remove my caries where i can proximately I sometimes like to finish the proximal boxes with sonic handpieces NSK do a great sonic handpiece and the proximal attachments that go with them are great for removing a prismatic enamel for ensuring that you don’t harm the adjacent proximal wall as well.
So we also like using those but i tend to use rose heads more than anything i use them with water so they could be ceramic or they could be steel but i tend to just go for steel because[Jaz] What about for beveling that enamel so you’re not ending up with a butt joint of the composite at the proximal? [Andrew] So when it comes to the actual prep of that of that particular part they tend to stick with the 20 micron red band composite finishing burs and in particular i quite like the rugby ball pear-shaped i tend to sort of try to eat flatten that out and then have my hand be sort of curve over a smidgen so that you’ve got the bulbosity of that rugby ball that then sort of makes a concavity at that point so i quite like doing that i have no hesitation with overlaying cusp tips either and Didier Dietschi did some research that would suggest that posteriorly your composite needs to be at least one millimeter in thickness on an occlusal layer so as a consequence of that if you’re gonna overlay your cusps tips you do need to take that down by at least a millimeter in an effort to then overlay and get strength of your composite material. So together with the red band 20-micron finishing bur and at least 1-millimeter reduction on the cusp tip, I’m quite comfortable doing that. [Jaz] Brilliant and just leaning on from that, at what point do you numerically or otherwise are you going to decide to cap that cusp or not? So what’s your cutoff point, do you think okay now this cusp is thin enough that I’m going to now remove a little bit to allow one millimeter of composite to cap that cusp? [Andrew] Great question so I’m going to answer that and I’m going to go back to the last point that I was going to raise on your first question. So the answer to that is I look at Pascal Magne’s research from 2009. He did some finite element analyses on different types of posterior cavities I’m not sure you’re probably aware of this particular piece of research and surprise what he figured out is that the weakest or the highest stress of would be the MOD and now that stands to reason because of course what you’ve got is a channel going straight through the middle of the tooth and then you’ve got these unsupported buccal and lingual walls and so he supported obviously the motion to then say okay well if you don’t have to do a MOD and if you don’t get rid of that middle part of the isthmus then don’t and then sort of you know to get rid of your GV black kind of classification and just do what you need to and then adhere to that which makes perfect sense.
Moving on from that however is that what makes me decide whether or not I cover the cusp tips or not is whether the distance between my cusp tips and the width of my isthmus that’s been created is and the ratio between those two distances, so if the distance between my isthmus that I prepped is over half the distance between my cusp tips then i will overlay the cusps if that makes sense. If I’m less than that then I’m quite happy to not overlay the cusp because i know that the thickness of my buccal or lingual proportions is going to be decent. The only time that changes is if we’re diverted onto one side more than the other and in which case if i got buccal that’s real thin but my estimate is still thin I’m gonna then still overlay that particular cusp tip because it’s very thin indeed that’s the only exception but I will rely on the science to guide me there.[Jaz] Brilliant. I knew you’re going to be coming on with references and stuff and I’ll try and put as many of these on for the Protrusive Dental Community Facebook group as well so people can geek out and you’re going to talk about isolation and you’re talking about the correct cavity form and that led nicely to all these accessory questions and i think there was one more point you were going to raise right in terms of staining. [Andrew] That’s correct. And the other way and the other thing that we’ve got to look at is the quality of the bonding that we get and one of the main things that we often miss out on is that we think that because the cusp tip is a relatively accessible area in terms of cleaning and hygiene we think that that’s clean and the difference is actually if you were to use something like GC plus and triple paste to then highlight your biofilm or some of the plaque. You’d be quite surprised with how much plaque indeed builds up and so actually what i tend to do is use particle abrasion. Particle abrasion is so important in making sure that your cavities are disinfected or as at least the biofilm has been removed as best as possible and I’ll overlay that onto the sides external sides of the buccal lingual cusps equally so that when I do perform either a custom overlay or I have a finishing point of my composite resin i know that that’s free of biofilm the same principle will apply from like a class 5 restoration, they look clean but to the naked eye they would look clean but you’ve got to make sure that you sandblast those areas to make sure you can remove that biofilm and I’ve found that since I’ve been using that and that’s been about 10 years now that has revolutionized the level of marginal leakage that I then get on the periphery of my composite restorations. [Jaz] But I was having a chat with Marcus Blatts and he was just coming out with all these you know the evidence for and against air abrasion and by against air abrasion I mean that there’s the lack of efficacy for it but there’s one in terms of bond strength that is how much does it improve your bond strength and there are some papers for and some papers against but there’s one thing that cannot be denied and that’s a removal of biofilm which is why I will routinely use it and i completely agree with you that you know once you scale and then you disclose you’ll still find plaque there but only after you use the air abrasion unit can you find that you’ve got a truly clean surface that is ready for bonding and recently David Gerdolle came on the podcast and he just blew us away about the two most important things about bonding being clean and rough so I’m glad you’re echoing those are those same sentiments. So talk about those three main areas of how to prevent having that staining and you know how air abrasion has revolutionized that.
So now let’s come to the fact that okay at what point are you gonna see these stained composites probably not yours probably from your predecessor and now decide, okay, now I’m gonna intervene because of this staining or this microleakage. [Andrew] So that’s a tricky one and i think that there is so much subjectivity that builds into whether or not to decide to intervene because of marginal staining and it may well be that we have to then communicate effectively with our patients when we do this because it may well be that certain situations don’t look complicated or infiltrated with caries but in fact when you open them up they are rife and it may well be for a host of different reasons it may well be because the bonding protocol was either old not so good, perhaps the quality of the bonding agent wasn’t ideal back in the day, perhaps the composite wasn’t cured in completeness.
There are so many factors that can contribute to whether or not you get propagation of that delamination going all through the tooth. So I guess in answer to your question I would do this if I see microleakage that can either be polished or gently smoothed down by means of either air abrasion or by use of rubber cups for example the chauffeur one glosses is a popular one in my hands or composite finishing burs and you see a finish that then is not stained or delaminated then perhaps that’s a good place to stop if however you see that then propagating then obviously you’ve got to go further in and you might end up having to then suggest to the patient that you have to remove the whole restoration.
The key in the answer this is really and truly communicate with your patient because the truth of the matter is that you may not know until you’re in that in that zone and so you have to then make sure the patient has the expectation they’re going to have to have that restoration removed and the solution presented to them alongside with the time and the cost and the risks to that patient and if it’s then ever more limited in terms of what you need to do then that’s only then a bonus and that’s a good way to look like the hero.[Jaz] Brilliant and we always appreciate these communication gems and that was one right there so I really appreciate that and one thing that we did also touched on obviously that you mentioned about, the cusp cupping which leads very nicely to the next question which is something I discussed on the podcast at great length with Chris Orr as well, it’s about at what point do you Andy want to go from the beautiful direct work that you do to say you know what I’m going to now move to indirect lithium disilicate or whatever for those big restorations? So what is it because you’re so gifted with these composites, for you to recreate the functional anatomy of composite comes easy at what point do you say you know what I’m not going to just cusp cap with composite I’m going to now consider an indirect restoration. What parameters go through your mind in that decision-making? [Andrew] Yeah, again I think the answer to that lies by stepping back and looking at the dynamic and static occlusion by which you’re treating. Look at how long that restoration has perhaps been in the position in place and how well that’s performed in the time. look at the level of fatigue that’s in place there, look at the opposing dentition is there anything that you can do to limit the further fatigue of a more simple direct restoration by for example removing that of a plunger for example, little things like that. The next thing that you need to look at is the ratio of the restoration to the tooth, if you’re in excess of about sort of 50 to 60 percent then I think there is absolute legitimacy for going for a semi-direct or an indirect restoration i say semi-direct because these days we’ve got more options than ever when you’ve got things like semi-direct composite works or pre-cured composites or ceramic hybrids when you’re dealing with milling and CAD CAM solutions. So I think that that world has really opened up in terms of using more robust harder materials that have great ability to protect the tooth moving forwards so if I was in excess of perhaps 50 or 60 percent of the ratio of the tooth to restoration and I was dealing with a static and dynamic occlusion that had the potential to worsen in a short time i would definitely go for a semi-direct or semi-indirect or an indirect. [Jaz] Amazing. That’s such a nice clear guideline and I think a lot of people find these guidelines helpful in their decision making tree and again I appreciate the fact that you’re looking at the opposing dentition, the functional risk of the patient, and the fatigue that you mentioned as well of the restoration as well and that’s fantastic and that leaves beautifully to our last big theme which is how do we manage, and these restorations which are these huge amalgams?
Now we’re talking maybe you said 50-60% I’m talking about these amalgams that are 80-90 okay let’s go for 80% of the tooth, right? So upper-lower molar 80% of the tooth is an amalgam it’s been there for a long time but we can see signs of fracture, we can see some ditching and you want to reduce the risk of fracture or catastrophic failure by intervening the problem is by intervening you’re not going to have many teeth left and really sometimes you think okay am I going to remove the whole restoration and commit this patient to a root canal treatment and then put a cusp post in this molar. Are there any other ways around treating this or some things that you some guidelines that you use for decision making because I have to tell you, Andy, I’ve shied away many times I’ve made a treatment plan for a patient for a quadrant but I will just work around that upper first molar we’ve got that behemoth amalgam because I don’t want to touch it any help you can give me?[Andrew] I think the first thing is communication as we said before, Jaz, we’ve got to look at communication and have our patient on board we should not be responsible for owning the clinical problems that the patient presents with okay so it’s really essential to every patient that comes our way that we say look we are here to assist we are here to help here is the problem at hand. Now we have a couple of options here but here are the risks that are the first thing because very very very quickly it can turn on you and I hate to go off topic I apologize but I think that that is so so important to make sure that you as the clinician don’t own the problems that the patient possesses first thing… [Jaz] That is key I love that [Andrew] The second thing is that by removing that restoration as you say when it’s 80-90 percent you run the risk of there being so little to that there’s not anything to work with so you are already telling that patient that root treatment is a possibility and if that is the case how are you going to then restore that too with an indirect restoration when there’s so little tooth that remains. So there are a couple of ways to look at this and I guess some of the more contemporary core build-up materials and I’ll include composite within that are probably a sensible way to then seal the underlying dentine and is as good as anything these days as the researchers suggested when properly treated.
So again if we were to then carefully and sympathetically remove the amalgam restoration that doesn’t mean going in with the fast hand piece until you see dentine or worse yet until you see pink what i do mean by that is perhaps sometimes using ultrasonic hand pieces to then try and blast off bits of the terminal part of the apical amalgam if you like i also mean using things like air abrasion to then try and remove the apical amalgam whatever you can do to try and be gentle in your removal of that material is a good way to go and then because you’ve used something like air abrasion you’re in a good place to then try and hybridize that dentine as well as predictably as possible pretty quickly I’m gonna get etch on there and leave it on there for no longer than about 10 maximum 15 seconds and then use a good fourth generation bonding agent like Kerr OptiBond 1 and 2 FL which is gold standard and then put a core in place I’m quite happy to build up a composite core in good nano hybrid composite because that’s nice and strong i know then it’s well sealed to the underlying pulpal area and then perhaps you can carry on your your prep from there that’s all done pretty quickly. You’ve got to be in a situation where you can engage the margins of your restoration.
So whether that be by using deflection or retraction cord and whether that be sort of some form of deep marginal elevation whether it be some form of crown lengthening you’ve got to try and make sure you can get onto sound margins where possible especially with direct restorations and I think that if you’re not, if you can’t visualize, if you can’t see your margins then you need to put yourself in a position where you can and that means either doing one of those things we’ve just talked about or then perhaps bouncing it off to someone who can perform some crown lengthening for you or something like that.[Jaz] I think the main takeaway there in those tough scenarios is all about the communication because the dentistry we can do, we can remove and then get some great tips in terms of atraumatically if you like removing these amalgams which is such a great thing to consider and then proper protocols in bonding under isolation to build your core and then considering something indirect from there but it’s all about that conversation in these big amalgam cases so i really appreciate you not digressing but really putting the foundation of that entire topic in its place. Andy, you’ve answered all my questions I really appreciate it so much. So the main two things want to ask now is any final words on this big topic that we covered and where can we learn more from you I know you run some courses and I’d love to know about this because I always get flooded every time I got a really interesting guest like yourself people always message me saying hey where can i learn more about, Andy. So I want to put your stuff on my website but also where you know what kind of where which countries do you teach in now? [Andrew] So I guess the first thing to say is that in terms of trying to then make sure that we adhere to good principles in terms of you know what the subject matter we were just talking about it’s really really important you train appropriately to get to that point where you can prepare the tooth in the most appropriate fashion. If I can just add one more point really quickly, Jaz is that and there’s a lot of evidence that supports the use of something like RelyX™ Unicem as almost like a base if you’ve removed that amalgam restoration then sandblasted. The reason is is because that self-etch is also cured you mustn’t let the dual-cure operate by itself because the exothermic is quite high so you want to light cure it quite quickly but then you can bond to that because it’s self-adhesive so from that perspective that’s a good material to use and then you can then… [Jaz] So like an indirect pulp cap? [Andrew] Basically, exactly that. So to your question, I own and run a company called indigo dent it’s been around for about four or five years now and what i do is teach in composite restoration anteriorly and posteriorly. I’ve been doing composite education I’m so lucky for in my I mean my 13th year of education now with composites and I’ve seen the layer of the land change hugely i’ve seen some wonderful talent emerge in the UK which you know which is just an amazing thing I really like to see that young talent emerge through and so I do anterior and posterior courses. I launched a tooth wear course about four years ago which has been as I’ve been told kind of one of a kind in terms of teaching a lot of the course.. [Jaz] People have been raving on about that my friend Maria Godfrey, she’s always banging on about how awesome that was i think you do it with Govinda right? [Andrew] Yeah, it’s one actually that I’m taking by myself these days but yeah we started off doing that but yeah it’s taken a long time to get the course into what it is now and we, you know, I’ve teamed up with Ashley Burn, who’s really helped me out on some individual exercises and things like that but there’s it’s a pretty heavy going course and I want every delegate to come well rested because you’re not going to be when you come on the course and there’s a lot of theory in it and there’s a lot of hands-on and it breaks through a lot of the mystery demystify a lot of the stuff that’s there and it makes it work systematically in a workflow that I can understand and I can then put across to the delegates. [Jaz] Well, please do send me the website and stuff so I can put that on for everyone to check that out. [Andrew] I will do, I’ll send you the link it’s www.indigodent.com so and then yeah I also offer photography I’ve done that for the RTI and such like so that you can actually get to grips with taking restorations document your work appropriately and do ethical marketing. [Jaz] Fantastic, Andy. It’s been an absolute pleasure and I love that you took this seemingly single tooth issue and I’m so glad you brought these. I’m so glad i wasn’t expecting to talk about constricted envelopes of function but I’m so glad we did because that’s another thing that is something that we don’t really touch on at dental school but this basic series in august that we’re doing. I’m so glad that you touched on it and the role of this episode or role of any podcast is never to give you the complete info. This is just 45 minutes so take Andy, what he’s saying as an inspiration to go and read more. Look up John Kois in the works of John Kois. There’s so much out there that you can learn for free and even when you consider going to Seattle or one of andy’s courses, the learning never stops. So thanks so much for sharing that all with us. [Andrew] It’s worth saying that you know just because we look at the whole dynamic occlusion and dentition as a whole it doesn’t mean we have to treat the whole dentition as a whole. You can still remain to be single tooth dentistry without having to treat the whole arch or all of the restorations there so it’s just a matter of stepping back and looking at the bigger picture. [Jaz] And classifying your patient in terms of risk and failure and having those communications. So great conversations with the patients which you really help with as well. So Andy thank you so much and i look forward to catching you at the dental events, my friend. When they go back up again run again.
Jaz’ Outro: There we have it guys the first episode of the back-to-basics series of august with Andrew Chandrapal. Thanks so much for listening all the way to the end. Hopefully, it didn’t get too complex around the whole occlusion and the loss of vertical dimension leading to a constricted envelope if you didn’t understand it, message us let me see if we can help you to understand that and now and again we’re making some helpful infographics you might have seen that recently the protrusive team has expanded we’ve got Erika, Krissel helping me out. We’ve got the producer John, myself. So the team’s getting bigger.
So the announcement really I want to make is that if you signed up to my splint course early on and one of the promotions I had hey if you sign up by this date then you’ll be part of the protrusive premium. Well something really awesome is coming to your inbox very soon just give me a few weeks and a really important announcement is coming very soon but anyway check out the next episodes i’m super excited for in two episodes time the episode will be titled ‘Regaining your confidence in extractions’ This will probably be the most profound episode I’ve done to date so I’m really excited for you to listen to that one but anyway I hope you enjoy the rest of august. As always I really appreciate you listening and I’ll catch you in the next one.