As the manager of a dental practice and the co-founder of the Deutsches Zahnärztinnen Symposium (DZÄS), an event that provides a forum for female dentists in Germany, Dr Frederike Fehrmann is an extremely busy woman. In this interview, she discusses her experiences as a woman working in dentistry and offers advice for those who are considering entering the field.

How did you decide to enter the field of dentistry?

I knew very early that I wanted to study dentistry. My mother is an orthodontist and I always liked what she was doing. During my studies, though, things looked different—I wanted to do oral and maxillofacial surgery for a period. But then I was offered the dental practice where I now work, and though it was different from what I had expected, I was still able to develop my skills in many directions, arriving finally at CAD/CAM and laser dentistry, which have been my favourite areas in recent years.

My professional life is constantly changing and developing, and that is what makes it exciting. High-tech dental surgery is exactly what I want to do and work with.

In your experience, are there any advantages or disadvantages to being a woman in dentistry? Have these changed over time?

I think dentistry is great, but it’s the same in this field as in many other professions in which women work. We often have a double burden simply because of our responsibility to bring the next generation into the world. This is a topic that has been on my mind for a long time. In fact, the DZÄS will be hosting a symposium in Frankfurt later this year where we will highlight the balancing act between technology and mindfulness, between career and family. I’m looking forward to it very much.

In my experience, women tend to have certain advantages—for example, we often find it easier to deal with children as patients than male dentists do. However, we still have to assert ourselves constantly. But things are changing. At the university near us, there are hardly any male dental students. It is time to rethink and adapt dental education to empower women to fulfil their potential.

How important is it to have peers and mentors with whom you can discuss dental issues?

Having other women with whom one can exchange ideas is worth its weight in gold. Sometimes you discuss your problems and suddenly find there is a simple answer that you yourself would not have thought of, one that makes your life easier. It’s possible to do without a mentor, of course, but things do become more difficult. Both peers and mentors make you strong and help you progress continuously. Besides, women often talk and listen differently and understand even without words.

What qualities and skills do you think are needed to succeed in the dental world?

I have had feedback from many patients who say that they like to see women providing treatment, as we can often read between the lines and might be more likely to recognise when they are afraid, for example.

Nevertheless, we frequently have to prove ourselves repeatedly. How often haven’t I heard the questions, especially as a young professional, “Are you able do that? Are you strong enough to remove that tooth?” I don’t think that a male dentist would be asked this.

Do you have any advice for girls and women considering a career in dentistry?

Just do it! Network and never, ever give up. Find a focus, something you do better than everyone else. Find mentors and colleagues who can help and guide you when needed. Educate yourself and find out what you’re passionate about.

Which Kuraray Noritake products do you employ in your daily workflow?

I use both KATANA™ AVENCIA™ Blocks and KATANA™ Zirconia Blocks in my CEREC workflow to produce CAD/CAM dentures. A colleague who works a lot with Kuraray Noritake told me about these blocks, and so I tried them out. The zirconia blocks impressed me by being super-translucent and variable in their colour texture. Their fit is excellent and the CEREC workflow is easy. The AVENCIA™ blocks are very simple to use because after milling they only need to be polished, not fired. This is particularly useful when supplying inlays.

As the manager of a dental practice and the co-founder of the Deutsches Zahnärztinnen Symposium (DZÄS), an event that provides a forum for female dentists in Germany, Dr Frederike Fehrmann is an extremely busy woman. In this interview, she discusses her experiences as a woman working in dentistry and offers advice for those who are considering entering the field.

How did you decide to enter the field of dentistry?

I knew very early that I wanted to study dentistry. My mother is an orthodontist and I always liked what she was doing. During my studies, though, things looked different—I wanted to do oral and maxillofacial surgery for a period. But then I was offered the dental practice where I now work, and though it was different from what I had expected, I was still able to develop my skills in many directions, arriving finally at CAD/CAM and laser dentistry, which have been my favourite areas in recent years.

My professional life is constantly changing and developing, and that is what makes it exciting. High-tech dental surgery is exactly what I want to do and work with.

In your experience, are there any advantages or disadvantages to being a woman in dentistry? Have these changed over time?

I think dentistry is great, but it’s the same in this field as in many other professions in which women work. We often have a double burden simply because of our responsibility to bring the next generation into the world. This is a topic that has been on my mind for a long time. In fact, the DZÄS will be hosting a symposium in Frankfurt later this year where we will highlight the balancing act between technology and mindfulness, between career and family. I’m looking forward to it very much.

In my experience, women tend to have certain advantages—for example, we often find it easier to deal with children as patients than male dentists do. However, we still have to assert ourselves constantly. But things are changing. At the university near us, there are hardly any male dental students. It is time to rethink and adapt dental education to empower women to fulfil their potential.

How important is it to have peers and mentors with whom you can discuss dental issues?

Having other women with whom one can exchange ideas is worth its weight in gold. Sometimes you discuss your problems and suddenly find there is a simple answer that you yourself would not have thought of, one that makes your life easier. It’s possible to do without a mentor, of course, but things do become more difficult. Both peers and mentors make you strong and help you progress continuously. Besides, women often talk and listen differently and understand even without words.

What qualities and skills do you think are needed to succeed in the dental world?

I have had feedback from many patients who say that they like to see women providing treatment, as we can often read between the lines and might be more likely to recognise when they are afraid, for example.

Nevertheless, we frequently have to prove ourselves repeatedly. How often haven’t I heard the questions, especially as a young professional, “Are you able do that? Are you strong enough to remove that tooth?” I don’t think that a male dentist would be asked this.

Do you have any advice for girls and women considering a career in dentistry?

Just do it! Network and never, ever give up. Find a focus, something you do better than everyone else. Find mentors and colleagues who can help and guide you when needed. Educate yourself and find out what you’re passionate about.

Which Kuraray Noritake products do you employ in your daily workflow?

I use both KATANA™ AVENCIA™ Blocks and KATANA™ Zirconia Blocks in my CEREC workflow to produce CAD/CAM dentures. A colleague who works a lot with Kuraray Noritake told me about these blocks, and so I tried them out. The zirconia blocks impressed me by being super-translucent and variable in their colour texture. Their fit is excellent and the CEREC workflow is easy. The AVENCIA™ blocks are very simple to use because after milling they only need to be polished, not fired. This is particularly useful when supplying inlays.

Though traditionally a male-dominated discipline, dentistry is increasingly welcoming women into the fold, and female dental students now outnumber their male counterparts in many countries. The Paris-based dental surgeon Dr Anne Longuet Tuet recently spoke with Kuraray Noritake Dental about the challenges that women may face in dentistry and what it takes to succeed in this environment.

Dr Longuet Tuet, how did you decide to enter the field of dentistry?

I have always wanted to work in a medical profession. Initially, I wanted to be a veterinarian, but then, at a certain point, I spent a lot of time in a dentist’s office. She was also a woman, a teacher at the local university, and I saw what she could do and was inspired to help people in a similar way in order to let them smile again.

In your experience, are there any advantages or disadvantages to being a woman in dentistry? Has the situation changed over time?

I regularly lecture, and this still tends to be a very male-dominated arena. For example, at a lecture last year in Tunis, there were ten of us on stage and I was the only woman. Being a female lecturer can sometimes be a bit of a disadvantage, as we often have to work harder than the average male lecturer to prove ourselves and receive the same level of recognition. However, this will hopefully change in the future as more women prove themselves to be highly capable in this field.

Do you have any female mentors or role models in dentistry that you look up to?

Someone I really admire is Dr Francesca Vailati, who has contributed so much to modern adhesive dentistry through her lectures and research articles.

How important is it to have peers and mentors with whom you can have discussions?

I think it’s very important to have female peers and mentors, but it’s also worth remembering that men should also be part of your network. It’s nice to see other women when I give lectures or attend conferences, of course, but I also have plenty of male peers I admire and who help me grow professionally.

If you don’t consider men for mentorship, you can really limit yourself in the dental world, so it’s better to be open-minded in this respect. Good mentorship isn’t necessarily related to sex but instead to knowledge, experience, charisma and a willingness to share your expertise.

What do you need to succeed in the dental world?

I think the most important quality is a commitment to lifelong learning. It’s dangerous to think that you know everything there is to know about dentistry—there’s always an area in which you can improve. Even when you’re at a certain level and have been practising for many years, there’s always some new technology or technique that you can learn or something that you can improve on.

Of course, this is not just on the personal level. Dental materials and technologies are constantly evolving, and if you stop learning about them, you stop being up to date, right?

This is especially true if you work in adhesive dentistry. You need to be aware of the new bonding products and materials that are introduced to the market, since this can be a way of improving your work and the cases you treat.

How were you first introduced to Kuraray Noritake Dental’s wide range of adhesive solutions?

It was about four years ago, just after I really began to develop my restorative and adhesive dentistry skills. I was looking for a way to improve my composites and the way I bonded my ceramic restorations, and a friend of mine told me that the company’s CLEARFIL MAJESTY™ range of composites was very good. I was sent some samples soon afterwards and have been using the company’s products ever since.

Which Kuraray Noritake products do you use in your daily workflow?

Since 80% of my work at the practice is now restorative dentistry, I use the CLEARFIL MAJESTY™ ES-2 composite every day, as well as Kuraray’s PANAVIA™ adhesive cement. In addition, the dental lab that I work with uses KATANA™ Zirconia regularly to manufacture dental crowns.

Though traditionally a male-dominated discipline, dentistry is increasingly welcoming women into the fold, and female dental students now outnumber their male counterparts in many countries. The Paris-based dental surgeon Dr Anne Longuet Tuet recently spoke with Kuraray Noritake Dental about the challenges that women may face in dentistry and what it takes to succeed in this environment.

Dr Longuet Tuet, how did you decide to enter the field of dentistry?

I have always wanted to work in a medical profession. Initially, I wanted to be a veterinarian, but then, at a certain point, I spent a lot of time in a dentist’s office. She was also a woman, a teacher at the local university, and I saw what she could do and was inspired to help people in a similar way in order to let them smile again.

In your experience, are there any advantages or disadvantages to being a woman in dentistry? Has the situation changed over time?

I regularly lecture, and this still tends to be a very male-dominated arena. For example, at a lecture last year in Tunis, there were ten of us on stage and I was the only woman. Being a female lecturer can sometimes be a bit of a disadvantage, as we often have to work harder than the average male lecturer to prove ourselves and receive the same level of recognition. However, this will hopefully change in the future as more women prove themselves to be highly capable in this field.

Do you have any female mentors or role models in dentistry that you look up to?

Someone I really admire is Dr Francesca Vailati, who has contributed so much to modern adhesive dentistry through her lectures and research articles.

How important is it to have peers and mentors with whom you can have discussions?

I think it’s very important to have female peers and mentors, but it’s also worth remembering that men should also be part of your network. It’s nice to see other women when I give lectures or attend conferences, of course, but I also have plenty of male peers I admire and who help me grow professionally.

If you don’t consider men for mentorship, you can really limit yourself in the dental world, so it’s better to be open-minded in this respect. Good mentorship isn’t necessarily related to sex but instead to knowledge, experience, charisma and a willingness to share your expertise.

What do you need to succeed in the dental world?

I think the most important quality is a commitment to lifelong learning. It’s dangerous to think that you know everything there is to know about dentistry—there’s always an area in which you can improve. Even when you’re at a certain level and have been practising for many years, there’s always some new technology or technique that you can learn or something that you can improve on.

Of course, this is not just on the personal level. Dental materials and technologies are constantly evolving, and if you stop learning about them, you stop being up to date, right?

This is especially true if you work in adhesive dentistry. You need to be aware of the new bonding products and materials that are introduced to the market, since this can be a way of improving your work and the cases you treat.

How were you first introduced to Kuraray Noritake Dental’s wide range of adhesive solutions?

It was about four years ago, just after I really began to develop my restorative and adhesive dentistry skills. I was looking for a way to improve my composites and the way I bonded my ceramic restorations, and a friend of mine told me that the company’s CLEARFIL MAJESTY™ range of composites was very good. I was sent some samples soon afterwards and have been using the company’s products ever since.

Which Kuraray Noritake products do you use in your daily workflow?

Since 80% of my work at the practice is now restorative dentistry, I use the CLEARFIL MAJESTY™ ES-2 composite every day, as well as Kuraray’s PANAVIA™ adhesive cement. In addition, the dental lab that I work with uses KATANA™ Zirconia regularly to manufacture dental crowns.

This BOND edition covers the pursuit for durable dental aesthetics.

Unique insightful articles from renowned clinicians and researchers of the likes of Prof. Bart Van Meerbeek, Prof. Dr. Florian Beuer and Dr. Hendrik Zellerhoff are waiting for you. 

BOND | VOLUME 6 | 03/20

We post the BOND also here for your convenience; Enjoy!

Previous versions:

BOND | VOLUME 5 | 05/2019

BOND | VOLUME 4 | 06/2018

BOND | VOLUME 3 | 10/2017

BOND | VOLUME 2 | 04/2017

BOND | VOLUME 1 | 12/2016

A strong and durable bond between the tooth and the restoration is a decisive factor influencing the long-term performance of dental restorations. The quality of the bond, however, is not only affected by the bonding agent or cementation solution used, but also by the condition of the bonding surface. For those who would like to ensure clean tooth and restoration surfaces in an easy way, Kuraray Noritake Dental has developed KATANA™ Cleaner, a universal cleaner with MDP salt and a pH of 4.5 for intra- and extra-oral application.

It has been proven that proteins present in saliva and blood have a negative effect on the performance of dental adhesives. Especially in indirect procedures, however, it is impossible to keep the bonding surfaces free of oral fluids. At try-in at the latest, the prepared tooth and the restoration are contaminated and need to be cleaned. Rinsing with water does not have the desired effect, and even with many available cleaners, a certain amount of proteins are usually left on the surface. Tests show that by using KATANA™ Cleaner or by sandblasting, the desired high cleaning effect needed is obtained, without compromising bond strength. This is true for KATANA™ Zirconia restorations, while KATANA™ Cleaner also leads to the desired results on dentin and enamel – surfaces in the oral cavity for which sandblasting and most of the other cleaners are not indicated.

The use of KATANA™ Cleaner offers yet another advantage: the cleaning procedure is extraordinarily simple, quick and neat. The universal cleaner comes in a bottle with an innovative flip-top cap, enabling single-handed dispensing onto the dish. It is then rubbed into the surface of the restoration and the prepared tooth structure or the abutment for ten seconds, rinsed with water and dried. Thanks to the high surface activity of MDP salt, these ten seconds are sufficient to remove the proteins on the substrate almost completely, creating conditions very similar to those found on a non-contaminated bonding surface. Subsequently, the selected bonding agent or cementation solution – e.g. PANAVIA™ V5 or PANAVIA™ SA Cement Universal – is applied according to the maufacturer’s usage instructions.

The result is a strong long-lasting bond, which gives users a peace of mind. Pilot users who have already tested the product agree that KATANA™ Cleaner is the easy way to optimise bond quality and streamline any adhesive procedure.

A strong and durable bond between the tooth and the restoration is a decisive factor influencing the long-term performance of dental restorations. The quality of the bond, however, is not only affected by the bonding agent or cementation solution used, but also by the condition of the bonding surface. For those who would like to ensure clean tooth and restoration surfaces in an easy way, Kuraray Noritake Dental has developed KATANA™ Cleaner, a universal cleaner with MDP salt and a pH of 4.5 for intra- and extra-oral application.

It has been proven that proteins present in saliva and blood have a negative effect on the performance of dental adhesives. Especially in indirect procedures, however, it is impossible to keep the bonding surfaces free of oral fluids. At try-in at the latest, the prepared tooth and the restoration are contaminated and need to be cleaned. Rinsing with water does not have the desired effect, and even with many available cleaners, a certain amount of proteins are usually left on the surface. Tests show that by using KATANA™ Cleaner or by sandblasting, the desired high cleaning effect needed is obtained, without compromising bond strength. This is true for KATANA™ Zirconia restorations, while KATANA™ Cleaner also leads to the desired results on dentin and enamel – surfaces in the oral cavity for which sandblasting and most of the other cleaners are not indicated.

The use of KATANA™ Cleaner offers yet another advantage: the cleaning procedure is extraordinarily simple, quick and neat. The universal cleaner comes in a bottle with an innovative flip-top cap, enabling single-handed dispensing onto the dish. It is then rubbed into the surface of the restoration and the prepared tooth structure or the abutment for ten seconds, rinsed with water and dried. Thanks to the high surface activity of MDP salt, these ten seconds are sufficient to remove the proteins on the substrate almost completely, creating conditions very similar to those found on a non-contaminated bonding surface. Subsequently, the selected bonding agent or cementation solution – e.g. PANAVIA™ V5 or PANAVIA™ SA Cement Universal – is applied according to the maufacturer’s usage instructions.

The result is a strong long-lasting bond, which gives users a peace of mind. Pilot users who have already tested the product agree that KATANA™ Cleaner is the easy way to optimise bond quality and streamline any adhesive procedure.

As co-editor-in-chief of the Journal of Adhesive Dentistry, Prof. Bart Van Meerbeek is one of the most respected authorities on the topic of dental bonding agents. Here, he discusses how they have advanced over the last three decades and what the future of adhesive dentistry might look like.

Prof. Van Meerbeek, how have bonding agents changed and advanced since you first began studying them?

I believe that the great progress dental adhesive technology has undergone in the last 30 years, and the progress in bonding agents in particular, has had a great impact on the field of dentistry and particularly on restorative dentistry, of course. Many of the current restorative dental procedures make use of adhesive materials and techniques and have advanced greatly compared with when I wrote my dissertation more than two decades ago on the topic of adhesion to dentine. Adhesion to enamel is, of course, relatively easy to achieve in comparison with adhesion to dentine, and when I first started researching this topic, I was limited to conducting clinical trials in which we were confronted with a relatively high number of restoration losses in the short term. I was lucky to have been able to witness first-hand the fast advancements dental bonding has made, having conducted research in this field now for nearly 30 years.

At a certain point, the research community started to realise that there is a smear layer in-between, which is created through cavity preparation, and that this layer interferes with bonding. If you want to achieve successful micromechanical and chemical bonding to the substrate, you first need to do something with this smear layer.

After this, we entered the era of conditioners and primers. In the past, the restorative community had been a little bit afraid of using phosphoric acid owing to its potential for pulp irritation. More and more, however, dental professionals began to use etchants with this chemical in them, as well as primers that effectively promoted bonding between the adhesive resin and dentine. While having achieved excellent bonding performance with multistep adhesives in the laboratory, as was later confirmed in clinical studies, further design and development of adhesive materials next focused on simplification and shortening of bonding procedures.

Out of this, two kinds of adhesives, making use essentially of two different bonding modes, arose: the etch-and-rinse adhesives and the self-etch, or etch-and-dry, adhesives. The newest generation of universal adhesives now enables dental practitioners to choose which of the two bonding modes to apply with one single adhesive formulation.

What advantages do bonded restorations offer over more traditional methods?

Bonded restorations are minimally invasive—the dentist doesn’t have to remove non-diseased tissue to create undercuts to keep the restoration in place, allowing for a more conservative approach. Keeping as much enamel as possible should be a goal of any restorative procedure, as it is simply the best tissue to bond to. Although bonding to dentine has always remained more challenging and has actually slowed down our adhesive endeavours for a long time, adhesively restoring teeth, involving also effective bonding to dentine, can today be achieved in a reliable, predictable and durable way.

Along with highly successful implantology to replace missing teeth, lessening the need for bridges, solitary tooth restorations have substantially increased in number. Bonding promoted the additional shift from conventional tissue-invasive crowns to tissue-preserving partial tooth restorations, as modern adhesives can hold such partial restorations in place on rather flat and even non-retentive surfaces. In addition, bonding procedures allow for more natural-appearing restorations to be achieved by techniques to adhesively lute aesthetic restorations made of glass-ceramics and even the strong zirconia ceramics that no longer can be considered non-bondable.

What is your opinion regarding the current generation of universal adhesive solutions?

I think that this generation is very good, but that they are still not always as good as the more traditional gold standard two-step self-etch and three-step etch-and-rinse adhesives when it comes to their intrinsic bonding potential to dental tissue. However, I do see it as a positive that many of these universal adhesives integrate the MDP monomer, which should be considered to be one of the best functional monomers available today, though it needs to be present at a high concentration and purity level.

The MDP monomer is, generally speaking, excellent at bonding to zirconia as well. When it comes to bonding to different kinds of ceramic as well as resin-based composite restorative materials, it is always helpful to know which universal adhesives contain silane and are claimed to no longer need further treatment of the restoration. This has the advantages of lower technique sensitivity and fewer procedural steps—provided that it does, of course, work. There is current scientific evidence that the silane incorporated in today’s acidic aqueous universal adhesives is, however, insufficiently stable. Fortunately, research is underway to develop new universal adhesives that contain other silanes with higher stability in water at higher acidity.

Overall, I believe that a restoration primer that contains a high concentration of silane along with the MDP monomer is still more effective than many universal adhesives for bonding to restorative materials, since these universal adhesives can contain many other ingredients that create a kind of competition within the material to reach and interact with the substrate surface, leading to lesser bonds.

Another shortcoming of universal adhesives is their thin film thickness and relatively high hydrophilicity, promoting water uptake and hence making them sensitive to hydrolytic degradation. In this light, it’s important to note that, when a viscous and hydrophobic flowable composite is applied on top of a universal adhesive, it can make up for this somewhat and allow for durable bonding to take place.

Is the MDP monomer crucial to the ultimate success of universal adhesives? Are there other factors that can influence this?

Well, it’s very clear that the MDP monomer is one of the most effective monomers available, given its primary chemical binding potential to hydroxyapatite. However, there are significant differences in the MDP monomer purity and concentration levels between these products, factors that are affected by whether or not the monomer is synthesised by the company itself or whether this process is outsourced. Essentially, a universal adhesive that contains a high concentration of very pure MDP monomer should perform the best.

Are there any specific advantages that a self-etch adhesive possesses?

The biggest advantage is that it doesn’t remove all hydroxyapatite and minerals present in dentine and so keeps the weaker dentinal collagen protected. Phosphoric-acid etching results in relatively deep and complete demineralisation with collagen exposure, making the bond more prone to degradation. Partially maintaining minerals around collagen using a mild self-etch adhesive additionally allows for strong ionic bond formation to take place when the adhesive in particular contains the functional monomer MDP. In addition, one should be aware that, while chemical binding doesn’t necessarily lead to higher bond strength, it can create better long-term bond durability.

What do you see as the next step in adhesive dentistry?

One possibility is to reduce the number of steps in the adhesion process with the final goal of having self-adhering restorative materials. There have been developments in this direction, including studies and commercial products, though the products haven’t always proved to be very effective and their bond durability is unclear. Now, however, there are newer materials coming to market with claims that they can be used with no pretreatment. Their clinical effectiveness, nevertheless, still needs to be proved and guaranteed before such self-adhering restorative materials could be used as true amalgam alternatives in routine dental practice.

Another possibility, and current R & D hype, is the development of bioactive adhesives. Many dental researchers and many companies want adhesives not only to deliver good bonding performance but also to have certain therapeutic benefits. What exactly a bioactive adhesive is depends on who you’re talking to. Some researchers believe that they should have antibacterial qualities, whereas others state that remineralisation of dentine and pulpal cell interaction are needed to qualify for the term “bioactive”. We certainly need to investigate whether we can give these materials these additional properties, but on one condition: that the adhesive material does not lose any of its original bonding abilities. That, in my opinion, is the biggest challenge for the future of adhesive dentistry.

As co-editor-in-chief of the Journal of Adhesive Dentistry, Prof. Bart Van Meerbeek is one of the most respected authorities on the topic of dental bonding agents. Here, he discusses how they have advanced over the last three decades and what the future of adhesive dentistry might look like.

Prof. Van Meerbeek, how have bonding agents changed and advanced since you first began studying them?

I believe that the great progress dental adhesive technology has undergone in the last 30 years, and the progress in bonding agents in particular, has had a great impact on the field of dentistry and particularly on restorative dentistry, of course. Many of the current restorative dental procedures make use of adhesive materials and techniques and have advanced greatly compared with when I wrote my dissertation more than two decades ago on the topic of adhesion to dentine. Adhesion to enamel is, of course, relatively easy to achieve in comparison with adhesion to dentine, and when I first started researching this topic, I was limited to conducting clinical trials in which we were confronted with a relatively high number of restoration losses in the short term. I was lucky to have been able to witness first-hand the fast advancements dental bonding has made, having conducted research in this field now for nearly 30 years.

At a certain point, the research community started to realise that there is a smear layer in-between, which is created through cavity preparation, and that this layer interferes with bonding. If you want to achieve successful micromechanical and chemical bonding to the substrate, you first need to do something with this smear layer.

After this, we entered the era of conditioners and primers. In the past, the restorative community had been a little bit afraid of using phosphoric acid owing to its potential for pulp irritation. More and more, however, dental professionals began to use etchants with this chemical in them, as well as primers that effectively promoted bonding between the adhesive resin and dentine. While having achieved excellent bonding performance with multistep adhesives in the laboratory, as was later confirmed in clinical studies, further design and development of adhesive materials next focused on simplification and shortening of bonding procedures.

Out of this, two kinds of adhesives, making use essentially of two different bonding modes, arose: the etch-and-rinse adhesives and the self-etch, or etch-and-dry, adhesives. The newest generation of universal adhesives now enables dental practitioners to choose which of the two bonding modes to apply with one single adhesive formulation.

What advantages do bonded restorations offer over more traditional methods?

Bonded restorations are minimally invasive—the dentist doesn’t have to remove non-diseased tissue to create undercuts to keep the restoration in place, allowing for a more conservative approach. Keeping as much enamel as possible should be a goal of any restorative procedure, as it is simply the best tissue to bond to. Although bonding to dentine has always remained more challenging and has actually slowed down our adhesive endeavours for a long time, adhesively restoring teeth, involving also effective bonding to dentine, can today be achieved in a reliable, predictable and durable way.

Along with highly successful implantology to replace missing teeth, lessening the need for bridges, solitary tooth restorations have substantially increased in number. Bonding promoted the additional shift from conventional tissue-invasive crowns to tissue-preserving partial tooth restorations, as modern adhesives can hold such partial restorations in place on rather flat and even non-retentive surfaces. In addition, bonding procedures allow for more natural-appearing restorations to be achieved by techniques to adhesively lute aesthetic restorations made of glass-ceramics and even the strong zirconia ceramics that no longer can be considered non-bondable.

What is your opinion regarding the current generation of universal adhesive solutions?

I think that this generation is very good, but that they are still not always as good as the more traditional gold standard two-step self-etch and three-step etch-and-rinse adhesives when it comes to their intrinsic bonding potential to dental tissue. However, I do see it as a positive that many of these universal adhesives integrate the MDP monomer, which should be considered to be one of the best functional monomers available today, though it needs to be present at a high concentration and purity level.

The MDP monomer is, generally speaking, excellent at bonding to zirconia as well. When it comes to bonding to different kinds of ceramic as well as resin-based composite restorative materials, it is always helpful to know which universal adhesives contain silane and are claimed to no longer need further treatment of the restoration. This has the advantages of lower technique sensitivity and fewer procedural steps—provided that it does, of course, work. There is current scientific evidence that the silane incorporated in today’s acidic aqueous universal adhesives is, however, insufficiently stable. Fortunately, research is underway to develop new universal adhesives that contain other silanes with higher stability in water at higher acidity.

Overall, I believe that a restoration primer that contains a high concentration of silane along with the MDP monomer is still more effective than many universal adhesives for bonding to restorative materials, since these universal adhesives can contain many other ingredients that create a kind of competition within the material to reach and interact with the substrate surface, leading to lesser bonds.

Another shortcoming of universal adhesives is their thin film thickness and relatively high hydrophilicity, promoting water uptake and hence making them sensitive to hydrolytic degradation. In this light, it’s important to note that, when a viscous and hydrophobic flowable composite is applied on top of a universal adhesive, it can make up for this somewhat and allow for durable bonding to take place.

Is the MDP monomer crucial to the ultimate success of universal adhesives? Are there other factors that can influence this?

Well, it’s very clear that the MDP monomer is one of the most effective monomers available, given its primary chemical binding potential to hydroxyapatite. However, there are significant differences in the MDP monomer purity and concentration levels between these products, factors that are affected by whether or not the monomer is synthesised by the company itself or whether this process is outsourced. Essentially, a universal adhesive that contains a high concentration of very pure MDP monomer should perform the best.

Are there any specific advantages that a self-etch adhesive possesses?

The biggest advantage is that it doesn’t remove all hydroxyapatite and minerals present in dentine and so keeps the weaker dentinal collagen protected. Phosphoric-acid etching results in relatively deep and complete demineralisation with collagen exposure, making the bond more prone to degradation. Partially maintaining minerals around collagen using a mild self-etch adhesive additionally allows for strong ionic bond formation to take place when the adhesive in particular contains the functional monomer MDP. In addition, one should be aware that, while chemical binding doesn’t necessarily lead to higher bond strength, it can create better long-term bond durability.

What do you see as the next step in adhesive dentistry?

One possibility is to reduce the number of steps in the adhesion process with the final goal of having self-adhering restorative materials. There have been developments in this direction, including studies and commercial products, though the products haven’t always proved to be very effective and their bond durability is unclear. Now, however, there are newer materials coming to market with claims that they can be used with no pretreatment. Their clinical effectiveness, nevertheless, still needs to be proved and guaranteed before such self-adhering restorative materials could be used as true amalgam alternatives in routine dental practice.

Another possibility, and current R & D hype, is the development of bioactive adhesives. Many dental researchers and many companies want adhesives not only to deliver good bonding performance but also to have certain therapeutic benefits. What exactly a bioactive adhesive is depends on who you’re talking to. Some researchers believe that they should have antibacterial qualities, whereas others state that remineralisation of dentine and pulpal cell interaction are needed to qualify for the term “bioactive”. We certainly need to investigate whether we can give these materials these additional properties, but on one condition: that the adhesive material does not lose any of its original bonding abilities. That, in my opinion, is the biggest challenge for the future of adhesive dentistry.

In the category CEMENT: Self Adhesive; PANAVIA SA Cement Universal was awarded Top Award 2020 by Dental Advisor.

Bond Strength:

As tested in DENTAL ADVISOR Biomaterials Laboratories, bond strength to dentin
and enamel were best in class for a self-adhesive resin cement.

Universal:

Since it can be utilized on any substrate, DENTAL ADVISOR
Laboratories tested the bond to both lithium disilicate and zirconia and
results were outstanding.

Evaluator Comments:
• “This cement is very strong and has great adhesive properties.
There was virtually no post-op sensitivity.”
• “Very user-friendly and cleaned up well.”