Question: Can you please help me with the issue of creating a adhesive hybrid layer in a proper way using various systems?

Hi Friends! I hve a question – can You please help me with the issue of creating a adhesive hybrid layer in a proper way using various systems? Can You please cast some light on a topic of some details, ex. primer and adhesive agitating? Long time ago I started to create adhesive player by placing primer in two portions at least and rubbing it thoroughly, but when it comes to adhesive I place it very gently without agitating in order not to introduce air bubbles into the layer. But this is only my point of (I hope – logical) belief. My deduction was taken from endodontics where – while you place a GP cone with sealer into the canal, you should do it slowly and from impression taking – I put impression tray very slowly onto teeth to avoid air bubbles. A few days ago a friend of mine spoke to a lecturer who has a similar way of performing this step. What is Your opinion?

John Comisi: Interesting Karol. I instinctively think that it all depends on the solvent used in the adhesive. I understand that we are trying to displace the water in the dentin tubules while at the same time maintaining their structure so the resin can infiltrate and become part of the “tissue engineering” process that Umer Daood has discussed in previous posts. So do you minimize air entrapment, perhaps; but do you enable the process needed to create a good hybrid layer, probably not.

Scott Dubowsky: The philosophical problem that often appears to crop up in clinical situations is that too often there is not a differentiation between what we “know” and what we “believe.”Personally I am wondering whether the quest to bond to dentin using conventional resins is just plain futile.

John Comisi: In my opinion Scott, it is. A better way needs to be developed. In fact it is available, and us making a difference. Biomineralization.

Umer Daood: In my humble opinion, it is not clear whether there is a substantial correlation between the laboratory data or clinical outcomes or vice versa, in predicting clinical outcome in a laboratory. So I would rather buy more what a clinician might say on this. The rubbing affect of adhesive on dentine is one of the ways to reverse the adverse effects of over drying. Naturally the rubbing motion is aiding a better infiltration of the monomers by increasing the kinetic energy on the dentine substrate which already has a high surface energy. Also the rubbing motion that you are carrying out pushes the collagen fibers, and inadvertently more space. John has a very accurate point when he talks about the solvent. Do u know while you are rubbing the adhesive, you can actually bring the water and solvent molecules onto the surface for its evaporation. I think active application may be the need of the hour. The rest I can leave it to you fine judgement as your post does have a point.

Karol Babiński: Thank you for discussing the topic. Dear Umer Daood – rubbing motion for primer is one thing but rubbing adhesive is what I try to avoid (maybe I’m wrong doing it this way). I try just to spread adhesive gently without too much motion as I believe adhesive’s role is not to dive into collagen mesh but rather to connect with primer’s monomers.

Salvatore Sauro: dear Karol……………Dr Pashley spent so much time working on this aspect when using the ethanol-wet bonding technique. I was with him in Augusta in order to demonstrate the importance of allowing better penetration of hydrophobic monomers (those i…See more

Karol Babiński: I think we have misunderstanding. My point isn’t to use only primer but to use primer 2-3 times with rubbing motion to engage Denton deeply and evaporate water and the to use adhesive one, but placing it very gently to avoid air bubbles incorporation into hybrid layer.

Umer Daood: Karol honestly I don’t disagree with your avoiding movement while applying. The only thing I had in mind was Johns idea of displacing water. I believe there is no other way to sandwich water molecules between resin and solvent other than this. But as I previously mentioned, for me the final call is the clinician’s. What’s your take ?

Karol Babiński: Thank you again. Ma take on this is that water and solvent are mainly a matter of priming. Water should be evaporated at this stage. I consider adhesive (second bottle) as a connector between primer’s monomers and composite resin. Therefore rubbing motion is more important during priming.

John Comisi: The key phrase in your statement there Karol is “Water should be evaporated”, but there is ALWAYS water in the dentin. Always.

Karol Babiński: So there a question arises – does rubbing motion applied to adhesive (second step) helps in any way with water evaporation? As far as I know, solvent is only a part of a primer. Am I wrong?

Salvatore Sauro: I do not think so, if we consider water, but the residual presence of ethanol within the demineralised primered dentine can reduce the solubility parameters of hydrophobic monomers and allow their penetration to form a hybrid layer more hydrophobic

Vivianne Pedrosa: Em minha conduta clínica há mais de doze anos aboli os adesivos simplificados por entender que estes exigem de mim maiores atenções e cuidados técnicos. A mistura de duas substâncias hidrofóbicas e hidrofílicas em um único frasco nos exige uma agitação prévia a aplicação….que pode ser esquecida ou ignorada no passo clínico. A forma de aplicação desses adesivos simplificados também são outro fator importante na dependência direta do solvente: se o solvente for a base de água e álcool o melhor efeito pela penetração do adesivo se dá com a técnica de uso esfregando ( técnica ativa)…se contudo o solvente for acetona o ato de esfregar pode acelerar a evaporação e com isso se ter uma peneiração menos profunda do adesivo e menor carreamento de água para o exterior do tecido condicionado

Umer Daood: well said. Facebook translation helped

Vivianne Pedrosa: Desculpe. Meu inglês não é um exemplo kkkkk

Umer Daood: Please not to worry about that

Vivianne Pedrosa: Além desses adesivos simplificados agirem como membranas permeáveis…é por isso não os considero como protetores pulpares. Por esses motivos uso apenas adesivos hidrofobico de três passos…onde a dentina e o esmalte irão ser preparados respeitando-se as características de cada substrato. Scotchbond como total etche o clearfill como self etch para mim são excelentes exemplos desses sistemas hidrofóbicos.