Hello all I thought I’d start my blogging career with a summary of my learning points from the BDA conference. I’m going to do it in 3 parts and hopefully give those who couldn’t make it (like Chris) an idea of what they missed.
After an early start and a three hour train ride, we arrived at Glasgow ready to start our learning curve at our first BDA conference. The Northern Deanery were out in force with all five schemes making the trip north of the border.
The venue was the fantastic Scottish Exhibition and Conference Centre; the design mimics the Sydney Opera House but affectionately called the armadillo by the locals.
So the stage was set, the lights dimmed and the BDA President John Drummond entered the stage to welcome the crowd. Peter Ward the BDA Chief Executive warmed the audience for the Keynote Speaker Charan Gill MBE, a Glaswegian entrepreneur and owner of the Harlequin Leisure Group. Known as Glasgow’s Curry King and was featured on the 3rd episode of ‘The Secret Millionaire’.
Charan spoke about his journey from his childhood experiences in the Punjab to prejudice streets of 1960’s Glasgow to owning the largest curry chain in Europe. An intriguing man with a fantastic story to tell, If you want to read more his cleverly named book ‘Tikka Look At Me Now’ is out now (sorry for the plug but the proceeds do go to charity and not the Inci-Dental blog).
The main objective of the lecture was to show how composite can be used in multiple clinical scenarios such as treating cracked cusp syndrome, tooth wear and full core build ups negating the need for an indirect restoration.
The first part of the lecture was comparing composite to amalgam. Obviously the main advantage most people think of is aesthetics, but they don’t stop there. Composite is an ideal restoration in small carious lesions as less tooth tissue is removed for the cavity outline form. So the old days of G.V Blacks ‘extension for prevention’ is long gone. Another advantage is the bonding of cusps together reducing the chance of cracks forming below the restoration. The data that Niek collated showed most of the amalgam failures are due to tooth fracture.
Some reported disadvantages of composite are post-operative sensitivity, reduced strength and poor contact points. Niek believes that 4th generation bonding system (which incorporate a separate prime and bond stage) reduces the post-operative sensitivity due to a stronger hybrid layer that doesn’t insult the dentinal tubules. With respect to strength of composite, most hybrid composites nowadays are durable to stand clinical practice so this should no longer be an issue. Niek mentioned that most of cracked or broken composite restorations were due to a GIC base (open sandwich technique) so this should be avoided.
Tight contact points are achieved using a sectional matrix system. They work by taking advantage of physiological tooth movement and wedging the teeth apart. There are several systems out there but they are more expensive then conventional matrix bands. Sectional matrix bands are all well and good for MO, DO or MOD cavities but for useless for large cuspal replacements or core build ups.
Niek gets round the problem by using a conventional matrix band to build the lingual and buccal aspects first i.e. restoring to an MOD cavity then swaps the matrix band for a sectional matrix for the contact points.
So what important points did I learn?
• Adhesive dentistry is ideal for minimally invasive dentistry.
• Hybrid composites are ideal for posteriors.
• A three bottle bonding system is the gold standard (separate stages for Etchant, Primer and Bond) but following the manufactures instructions is key.
• Enamel, dentine and staining shades are really not necessary; Niek only uses A2 or A3 depending on the age of the patient. Time is better spent on incremental layering of the composite.
• To achieve an ideal tight contact point sectional matrices are needed.
• Research has shown that open sandwich techniques (GIC under the composite) have a higher failure rate then total etching composite.
• Rubber dam is not necessarily needed but good isolation is the key, be it with cotton wool rolls and suction or a rubber dam.
• Composite can be used to bond cusps together to treat cracked tooth syndrome.
For further information about the speaker:
Niek Opdam, a Specialist in Adhesive Dentistry and Assistant Professor in Cariology and Restorative Dentistry at the University of Radboud, Nijmegen, Netherlands.
So overall it was a very interesting and informative lecture. The main reason for Nieks interest in composite is due to the shift from amalgam to composite in the Netherlands, with many countries doing the same who knows when the UK will follow suite. The only concern I have with posterior composites is it takes a lot longer to distinguish between restoration and tooth. So what do you guys think? Any tips or techniques is most welcome.
Zaid

#1 by ChrisO'C at June 9th, 2009
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I’m suprised that he didn’t recommend all posterior composites to be done under rubber dam. I’ve always found this quicker and more effective than messing around with saliva ejectors.
Lets say I’m doing a 46 MO. I’d cut 3 holes and cut between them with sharp scissor to make a split dam. Use a wingless clasp on the 7. stretch over the dam and put a wedget between 35 and 34. Then use normal metal matrix band. You usually get a slight bleeding when you place the matrix so I put a paper point below the wedge I use.
I also use flowable composite for the bottom of the box and then build incrementally. The only time I do a posterior composite without rubber dam is if the cavity is entirely occlusal.
Not sure how I feel about flowable composte at the floor of boxes now. I worry it will be a weak point in the restoration and I’m considering stopping using it.
Not seen those sectional matrix bands before though and always thought prime and bond together was good enough. Certainly some food for thought.
Chris
#2 by Alexandra at June 10th, 2009
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Hmm- don’t do posterior composites if i can help it but always with rubber dam (helps with tongues too)
I’ve heard from loads of people now that prime+bond isn’t as good as etch, prime, bond. I went to a lecture by Pascal Magne who talked about that pretty incessantly!
It makes sense if you think about it, i never used the one step stuff when the hospital was trying it and i’m pleased to be proved right!
I’m not a fan of flowable, less filler=more contraction away from my margin= endo (which is never a good thing in my hands)
Heating composite makes it behave like flowable but with the better filler content, i’ve used a water bath in the hospital but a baby’s bottle warmer can also work. Magne cements all his veneers with heated composite- margins will stain less??
Alex
#3 by Pete at June 10th, 2009
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As far as I know bonding to dentine is a done deal. We have the technology, even if using a two step bonding procedure. The primary problem with the bond is still shrinkage of the composite during curing, not bond strength even if you do not separately etch, prime and bond.
However, there is light at the end of the tunnel with the development of composites that work by ring opening polymerisation (Filltek Silorane Low Shrink Posterior Restorative System). This reaction results in dramatically less volumetric shrinkage.
Based on my experience of one step bonding, I wouldn’t use it for anything except orthodontic brackets!
#4 by Simon at June 11th, 2009
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Alex’s tip is a good one i’ll give it a try although i’m not entirely sure the manufacturers would recommend heating up your composites! I have do disagree slightly with not using flowable composites though. What better way do we currently have for lining the floor of our posterior cavities for placement of direct restorations than this? I’m not suggesting using gallons of the stuff as the shrinkage could be a serious problem, but the bonded restoration has the potential to significantly reduce post operative sensitivity when used in conjunction with an incrementally placed heavily filled composite. There are some good reports coming out about 3M’s silorane as Pete has discussed above. Remember though if you are going to switch to this hide your other bonding agents in a locked room so you don’t get handed the wrong one as it most definitely wont work!!
#5 by matt at June 11th, 2009
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I’m in the Alex camp – flowable comp is banned in my surgery! The lack of filler content and high polymerization shrinkage must surely negate any benefits of its nice immediate adaptation. I feel my time is better spent adapting the hybrid composite as well as possible (nice tip with the bottle warmer – also can be used for warming hypochlorite irrigant. It seems we shouldn’t be without one!).
If the gingival cavosurface margin is on cementum an open sandwich restoration is my choice. I worry about dentine bonding here for a few reasons:
1. Proximity to the papilla means avoiding moisture contamination is difficult, even with dam, a well fitting matrix and wedge.
2. Even with the best DBA, the bond to dentine will degrade with time, I like all bonded margins to be on enamel as this is more durable and will protect the underlying bonded dentine from the oral env.
3. With 2 margins bonded to enamel and one bonded to dentine/cementum, polymerization contraction is bound to be towards the most strongly bonded surface ie enamel. The resultant marginal gap will be a major cause of failure.
I cound show you any number of bitewings where a margin on dentine has not taken (with recurrent decay) while an adjacent margin on enamel is still doing good.
Conventional GI is not indicated for the open sandwich, it is soluble and will wash out. RMGI (Fuji II LC or Vitrebond) are less moisture sensitive, easier to handle and radiopaque. Their HEMA content will allow them to copolymerize with the bonding system to some extent. Using a non-composite for a cavity surface also lowers the c-factor of the cavity, further reducing polymerization stress and chances of the bond pulling away.
My rationale is I’d rather it fail due to chipping than pulpitis and the rest.
Even for a deep occlusal I’ll do a closed sandwich. Even though all margins are on enamel the polymerization stress is high due to the number of bonded surfaces. The RMGI base again reduces the C-factor and provides a secondary adhesive seal over the pulp should the bond break down at any point. If the cavity base is on pink dentine and necessitates a dycal or mta indirect pulp cap then this has to be protected with RMGI/GI before acid etching, again indicating a sandwich approach.
I like the sandwich approach (open or closed) with the current 5th gen bond (Scotchbond 1) and composite (Z100) I use, I see it as an extra adhesive safety net protecting the pulp should any bond failure/leakage happen.
Please don’t hold back criticising my approach, we’re all reading/commenting here to learn how to get better!
Cheers
#6 by ChrisO'C at June 11th, 2009
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Matt I agree with you. We got some vitrebond in early this year. It is excellent. Fot those who don’t know it is a light cured RMGIC which can be used as a lining material. it is much easier to place than caoh cements and sets immediatly with light. I would highly recommend it for indirect pulp caps used over your dycal or MTA too.
I always thought with composite though that you want to get as much bond as possible. It is a huge surface area your missing out on by placing a liner and dentine bonds can be very reasonable. For this reason I’ve always avoided any kind of lining for composites if i can.
I’ll have a think on what you’ve said though Matt and do a little reading. It’s a very interesting point.
On the other subject If your heating up composties could that not increase the amount of shrinkage? You would now be getting both polytmerisation and heat contraction. Also could it release free radicals and start the polymerisation process early making the composite less flowable? Just a thought.
Chris
#7 by Matt at June 11th, 2009
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For a deep occlusal I worry about the ratio of bonded to unbonded surfaces and the effects on bonding (and what will happen if it fails if I’m not protecting the pulp). This is no doubt a gross oversimplification but eg in an occlusal there are 5 bonded walls (m,d,b,l,floor) compared to 1 unbonded surface (occlusal). When composite cures it wants to pull towards the bonded surface but at the same time it shrinks, something has to give. This stress generated means the bond could pull away from one margin if stress is greater than the bond. Obviosuly the oblique layered incremental technique we were tought compensates for this but I always like my safety nets.
I couldn’t care less about the contribution of a dentine bond to deep dentine when my margin is totally bounded by enamel…
Deep dentine is full of tubules and is very wet, because of the number of tubules most of the mineral is peritubular dentine, it is the collagen of intertubular dentine that we rely on for the hybrid layer. Not to say the DBA won’t work here, but if the bond fails further up at any point (one possible mode of failure is polymerisation stress, which I can reduce by eliminating one bonded surface) I know I have the RMGI sealing the very pourous deep dentine against bacterial microleakage so its really just a second line of defence for the pulp in case of failure.
Despite the fact I could talk for England I am a very underconfident clinican and find myself reading too much to make sure I’m not doing any patients a disservice. I’ve probably totally lost the plot firstly using and now trying to explain my methods!!! Please tell me if I’m not seeing the woods for the trees.
Chris this blog is excellent, I think we are all questioning our daily routines. My head is killing, a trained monkey shouldn’t have to think this much!!
#8 by Pete at June 11th, 2009
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When I was in practice for deep occlusal restorations I used either a LC RMGIC base, for Composite or Amalgam, although for Amalgam if I had the time to allow the GIC to set sufficiently to pack amalgam on it I would use that instead.
I did have theoretical reservations about using LC RMGIC though as although I liked the rheological properties and the handling the HEMA content did concern me. We all know that the base of a cavity can be a moist environment with fluid levels replenished from below by the dentine tubules, and HEMA is known to result in Hygroscopic expansion as it takes up water. RMGICs definitely do take up water as that is what allows the small amount of acid base reation to occur leading to low but long term levels of fluoride release. I just didn’t like the idea I might have placed a lining that might expand with time.
#9 by Matt at June 12th, 2009
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Expansion will be good in terms of marginal seal but from what you said could well be the cause of failure of open sandwich fills due to fracture. I guess it will swell even more in this situation as the open part is exposed to the saliva, GCF etc.
I’m not sure what stress the expansion places on the dentine bond. RMGI luting cements are said to expand enough to crack porcelain restorations so it could be a fairly high stress.
…..Cheers Pete, I’ll keep an eye out for fractures!
#10 by Andy at June 16th, 2009
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The argument about using open/closed sandwich with composites is an interesting one…. I must admit after hearing Niek at the conference i would be convinced enough to nolonger use open sandwich with RMGIC or GIC. His arguement was that open sandwich in this manor results in a fulcrum-type effect with the strongly bonded composite on the weakly bonded GIC which therefore ends in fracture of the restoration and tooth. This fracture seemed to be by far the highest cause of failure of these restorations. If i come across the paper I’ll post a link for people to decide for themselves! I guess this would be reduced with a RMGIC and Vitremere/vitrebond are both quality products, but i would still use flowable composite for the floor of a box and have found it overall to be pretty handy for this purpose if use judiciously. Everyone has their preferences i guess. As for protecting the pulp, both Niek and Pascal Magne advocate etch and bond straight away after prepping to seal dentinal tubules…magne does this even before he takes impressions for indirect restorations. I would love to see some research comparing this to indirect pulp capping to see if its any better. Personally im still direct pulp capping, though not as much as I used to.
#11 by Alex Jones at June 17th, 2009
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Having spent a lot of time doing postgrad courses in restorative dentistry I have a few observations here. The point about the ratio of bonded to unbonded surfaces is a good one. This actually makes the occlusal composite the hardest to place.
Here are my observations (from a lot of literature reviewing as well!). After etching it is essential to re-wet the dentine to decrease any osmotic effects caused by over-drying which will pull the nerve processes up the dentine tubules and cause post op sensitivity. I use tubulucid which also disinfects thus removing any bacteria that may stil be in the tubules and then place onestep bonding agent (optident) over the top and cure for 10 secs. In an occlusal a thin layer of flowable composite can be used to ensure the floor of the cavity has a good first layer with no potential pul back and so air gaps under the restoration. This shoulod be as thin as possible and can be painted on. What no one else has suggested is to then use chemical cure composite to build up the bulk of the restoration. This has less shrinkage and can also be well packed in place ensuring no gaps and less stress on the remaining tooth tissue through polmerisation shrinkage. It is then straightforward to build each cusp in any hybrid composite and light cure. Following polishing and shaping it is a good idea to then re etch the restoration and its margins and apply a filled surface sealant (Bisco fortify from Optident) cure for 10s then place a layer of glycerin and cure for a further 20s. The glycerin removes the oxidative layer and allows complete polymerisation.
In a class 2 cavity the best way to restore is to use the sectional matrices already described (Dentsply palodent sytem) and a flexiwedge and first place the wall to be replaced then restore as per a class I cavity.
As far as pulp capping goes, if the bleeding stops within a few minutes the exposure is probably iatrogenic and will recover so etch, tubulicid and bond, if bleeding continues longer the pulp is probably infected and will need rct.
Preps can be protected in the same way prior to taking impressions (sealing the dentine) but care must be taken to ensure any excess bonding agent is removed as this will interfere with the silicone set. Either sit patient up and leave for 5 minutes and allow saliva to do its job or gently polish with a rubber cup.
#12 by Matt at June 17th, 2009
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Regarding pulp ‘crapping’ we probably shouldn’t be doing it at all as endodontic success for a vital pulp RCT is not too far off 100%. I don’t think the success of either method of pulp cap could get close to that.
Nevertheless some patients are not candidates for endo for a number of reasons and if a carious exposure of a vital, asymptomatic pulp is expected my personal choice is an indirect pulp cap. Why?
1. remaining dentine thickness is related to ability of odontoblasts to survive and ability to form reparative dentine. Some form of dentine bridge is already there!
2.I know I will not let infected debris into the pulp which will further increase level of inflammation.
3.I need not concern about pulpal heamorrhage ruining my seal.
4.Antibacterial pulp capping material will disinfect the deepest layer left and sealing it in with an adhesive restoration will incarcerate it and arrest the caries.
I don’t do these very much (prob once or twice a month). For caries removal I use a caries disclosing dye and 2% chlorhexidine under rubber dam. Only firm leathery dentine lying immediately over the pulp is left. Saliva contamination is bound to finish the pulp off.
Many of these pulps will be irreversibly inflamed despite being symptomless and neither pulp cap will work. I think indirect is the best of a bad bunch but if either method is used the tooth needs to be watched very closely…. if we choose to pulp cap then the pulp becomes infected asymtomatically and then we do endo for chronic apical periodontitis we’ve just lost 10-20% of the success we could have had…..
…. probably best to do the endo if everything allows it.
Cheers
#13 by Matt at June 17th, 2009
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Just read that back – a very slowly rotating bur is used for caries removal – caries dye and chorhexidine are adjuncts, they don’t remove anything!
#14 by Andy at June 17th, 2009
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don’t worry…i just read mine back and i meant indirect pulp capping, not direct. but when i expose during a cavity prep, unless its pinpoint and the cavity is now free from caries, i do generally begin RCT for the reason Matt said.
Good tip on the chlorhex though. hadnt ever heard that before, so will give it a go!
#15 by ChrisO'C at July 23rd, 2009
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Hi I’ve meant to put this comment up for ages, it kept slipping my mind.
I asked Phil Broughton about some of the issues raised in this post on our recent study day (see post reflection on proactive performance). The following is a summary of what he answered (but I concede I may have miss interpreted)
When asked about open or closed sandwich composites he said that he usually placed composite only restorations if the box finished on an enamel margin. However if the box was deep and into dentine/cementum he would use a GIC base. The difference in his technique being that he would build the whole tooth in GIC and get the patient back another day to cut it down and place the composite. This was because he felt the GIC had to fully set before composite could be placed over.
I guess this would work the same way as Mat who uses a RMGIC base (which is fully set because it is light cured) but would have the advantage that there would be no expansion as with RMGIC due to HEMA content. I thought it was a neat idea place a capsulated GIC restoration with matrix, book back in (say in 3 months) then composite
Phil agreed with Alex that the occlusal composite is the most difficult because of the varying bond ratio’s. I asked about placing self cure composite under a top light cure layer but the opinion in the study group was that self cure composite only cures to around 50% and should never be used when light cure composite is available. (i guess this also means to light cure your duel cure cements not just oxyguard).
However he did not advocate a base of GIC/RMGIC to counter these contraction forces. Instead he emphasied the need to build the composite up in layers. I suppose this should even appy to a very small composite restoration.
Anyway just some food for thought. Not sure we’ll ever get a definative answer on this everyone sems to give different advice!
#16 by David Bentley at July 29th, 2009
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Few good tips picked up from John Kanca III on a course earlier this year. He also recommended 3 separate stages for bonding, don’t think there is any doubt about that anymore. Even the companies admit the old ones are the best! He also said his company (cel surprise!) had come up with a 9th generation system that was better than the lot (Apex dental – available through Optident). His spiel was good and very convincing but I haven’t used it. He did basically invent the concept of bonding to teeth so I guess if he doesn’t know it, it’s not worth knowing!
He says he uses bucket loads of flowable and practically builds up full teeth from it on occasion. He’s not concerned about bond strengths (still much greater than GIC/RMGIC). He hardly ever uses sandwich techniques and that you can get away with composite.
He is happy to bond directly over small, vital exposures but says if you’re concerned you can use a small spot of Duralon (carboxylate cement!) to cover it and apparently healing can occur around it. Hadn’t heard that one before.
I’ve used a lot more flowable since this talk and have noticed a lot less people complaining of sensitivity.
Good speaker and not in the UK very often so would highly recommend it if you get the chance. This point got me thinking about a potential discussion topic…
…”Which speakers would you recommend going to see?”
I have seen some really good ones and some rubbish since graduating. I was led to believe my tutors (at Manchester) were all great and you should take everything they say as gospel but since I have realised a lot of what they said was unfounded rubbish. Even many of the consultants appear to be stuck in a timewarp from when they did their MSc/Phd. Lets be honest, who ever questions them?
Anyway, more food for thought. Would be interested in peoples comments.
#17 by Jason at March 7th, 2010
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Ok.. this is my understanding in the topic of flowable CR. Contraction stress(which forms marginal gaps and create post op sensitivity) is actually more dependent on the different modulus of elasticity than shrinkage . A CR with a high modulus elasticity (very densely filled) will produce higher shrinkage stress during polymerisation (Kleverlaan and Feilzer 2005). A prosthodontist I talked to simplified this phenonemon by saying ‘the contraction stress is essentially produced by the pull between filler particles (silica/zirconia). Densely filled CR has more boys pulling, which overrides the benefit of having lower resin component to shrink’. That statement is fine but didn’t take into account the ability of polymer to rearrange and relieve stress (flow). The addition of prepolymerised cluster also changes things a bit. It does make sense to use flowable CR as the first layer to create a better (lower stress) CR/tooth structure bond, and fill the rest of the cavity with a densely filled CR for better strength and wear property. Let me know wut u guys think!!
#18 by matt at March 7th, 2010
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Hi Jason,
Your comment has just led to me clicking back on this one from last summer. I learnt a lot from everyones comments on this one and, being the main opponent of it on here back then, am now using flowable composite for the applications people suggested.
Thanks to you all for your help, this is much cheaper than a CPD course!
#19 by Zaid at March 8th, 2010
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I am really pleased that this thread has gotten so many comments! I have learned as much from these comments as I have from the actual BDA talk. I think the comments are a credit to what the blog is actually about.
#20 by Dentist in milpitas at July 12th, 2010
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This the farthest most replied thread I’ve seen for this day. Zaid is right.
#21 by Toronto Dentist in Etobicoke at August 13th, 2010
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Great comments on bonding on this post. Glad to know I’m not the only one obsessing over this stuff.
My approach? With a thin layer of flowable, you reduce the risk of any voids at the pulpal floor from instrument pullback and such. Consider it my little security blanket over the pulp.
Joe

Etobicoke-Toronto Dentist (Canada)
http://www.RoyalYorkDental.com
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