Interview: "the term 'regeneration' is very misleading..." Dr. Paul Abbott

Before taking a full-time University position in 2002, Dr. Abbott spent 17 years in private specialist practice in Perth and Melbourne. He was Dean and Head of the UWA School of Dentistry and Director of the Oral Health Centre of WA from 2003-2009. Prof. Abbott has lectured extensively (over 1,000 lectures and courses) in 48 countries, has published over 225 articles in refereed journals and 25 textbook chapters. He was the Editor-in-Chief of the international refereed journal "Dental Traumatology" from August 2015 until December 2022. He has served on Editorial Boards and Scientific Review Panels of 17 other international journals. Read more here

Dr. Shikha Sharma: With your extensive experience in both private practice and academia, what inspired you to pursue a career in dentistry, particularly in the specialized field of Endodontics?

Dr. Paul Abbott:

My interest in dentistry was sparked when I was in high school. For many years, I had aspired to be a medical doctor but then I discovered dentistry - partly through talking with my own dentist at the time and partly through talking to some dental students that I knew. I liked the idea of doing practical things - i.e. clinical procedures - and dentistry certainly had a lot of that whereas medicine seemed to be more consulting and prescribing unless you were a surgeon. In those days, dentistry was a small profession in terms of the number of dentists and they enjoyed a very high profile of honesty and professionalism within the community. Hence, I changed my mind and applied for dental school - and the rest is history! Then, during dental school, I particularly enjoyed the theory of Endodontics and the clinical challenges. There were very few Endodontists in Australia at that time so after 4 years of general practice, I was lucky enough to be accepted into the Endodontic training program at The University of Adelaide under the supervision and teaching of Prof. Geoffrey Heithersay. This was definitely a turning point in my life. Prof. Heithersay was an incredible role model, mentor and inspiration. I was also very fortunate to have Prof. Rory Hume as my research supervisor and he, along with Geoff Heithersay, inspired the research aspects of my subsequent career.

Your tenure as an Editor-in-Chief of Dental Traumatology spanned nearly a decade. Could you share some insights into the evolving landscape of Dental Traumatology during this period and any significant advancements that have shaped the field?

Dental Traumatology is a unique area within dentistry as it involves every specialty area. Being the Editor-in-Chief of the journal meant that I had exposure to research in all the different specialty areas, as well as having the opportunities to meet and work with experts from all these fields. Dental traumatology is still an area that many dentists struggle with and this has particularly become evident over the last decade as many research projects have investigated this. These studies have highlighted the considerable need for continuing education of dentists, as well as education of the general public in what to do when faced with a traumatic dental injury (TDI). Research is also ongoing in areas such as tooth resorption, splinting and emergency management of TDIs. Conservation of the dental pulp whenever possible is not a new area of research but it has become of greater interest in recent years with the push to do treatments such as a partial pulpotomy whenever possible to preserve the pulp.

With over 232 articles in refereed journals, 25 textbook chapters, and 47 newsletter articles, your contributions to dental literature are vast. How do you balance your academic pursuits with clinical practice, and what advice would you offer to aspiring researchers in the field?

I believe that it is very important to have a balance between clinical practice, research, teaching and service to the profession if you want to be an effective academic. Clinical practice is very important to maintain your clinical skills as well as to ensure the relevance of your research and teaching to clinical practice. For the first part of my career, I was predominantly a private practice clinician with part-time university work. I then switched to become a full-time academic and in the Australian system, full-time academic dentists can do the equivalent of one day per week of clinical practice. Another important aspect of being an academic is to surround yourself with students and colleagues, and to collaborate with experts throughout the world who have common interests with your own work. This not only ensures that you always have other people contributing their ideas and opinions, but it also ensures that your work maintains relevance to the profession with the ultimate goal of trying to improve the experiences and outcomes for our patients.

Your research interests encompass a wide range of areas within dentistry, including tooth resorption, pain control and disinfection of the root canal system. Could you highlight some recent developments or breakthroughs in these areas that hold promise for improving patient outcomes?

Most of these topics have had slow, steady progress rather than "breakthroughs" - but this is typical of most research in dentistry. With tooth resorption, there is still a lot of uncertainty about the best management for the different types of resorption. We have shown that corticosteroid/antibiotic intracanal medicaments work very well to prevent external inflammatory resorption as well as arresting this type of resorption if it is already present. The key to preventing it is early intervention following injuries where the PDL has been damaged and where the pulp is unlikely to survive - in these cases, start root canal treatment as soon as the tooth is repositioned and stabilized, and place a corticosteroid/antibiotic medicament. Unfortunately, we have not really made any progress in preventing external replacement resorption. In addition, external invasive resorption is still an intriguing condition and one which is not fully understood. With respect to pain control, many studies have investigated things such as pre-operative anti-inflammatory agents, different local anesthetic solutions and different types of injections. Strategies have been developed to manage intra-operative pain much more effectively now. Disinfection of the root canal system still relies on the use of sodium hypochlorite and EDTAC, followed by medicaments such as calcium hydroxide.

As the former Dean and Head of the School of Dentistry at The University of Western Australia, and Director of the Oral Health Centre of Western Australia, what strategies did you implement to foster excellence in education and research within the dental community?

I was very fortunate when I became the Dean of our School because we had just moved into a new building one year prior to my appointment. This new building was the Oral Health Centre of Western Australia. It was a state of the art facility with all the latest equipment. it was also developed as a new model of dental health care delivery with a new funding assistance form the State Government whereby they subsidized the dental treatment of low income patients. As it was new, we had a lot of work to do to establish policies, protocols, workflow, etc. We also developed a new undergraduate dental curriculum to suit this new facility and we refined this curriculum over the 7 years that I was Dean. Alongside all this, we started new postgraduate programs and expanded the existing programs. Having these postgraduate programs was then a boost to our research output and this helped us to attract more students to do Masters and PhD degrees by research. It was an exciting time and I am proud of what we achieved through the dedication of our many staff members and students.

Having delivered over 1000 lectures and courses in 50 countries, what do you find most rewarding about sharing your knowledge and expertise on a global scale, and how do you adapt your teaching approach to diverse audiences?

I love to teach and to meet people - especially students and colleagues. It is always rewarding to talk to people after I have given my lectures so I can get feedback and answer their questions on an individual basis. It is through such discussions that I can learn new things myself, and particularly develop an understanding of the "local situation" if I am in a different country. It is important to have an understanding of who makes up your audience as the level of background knowledge can vary a lot, and the level of experience also varies considerably. Although I tend to teach the same material at all levels (undergraduate, postgraduate, continuing education, general dentists, specialists, etc.), the way I present it and the depth that I go into will vary according of the make-up of the audience. This can also be affected by knowing the "local situation" as treatment approaches, materials, instruments, etc. can vary from country to country, and even from city to city.

Given the rapid advancements in technology and techniques within dentistry, how do you stay abreast of the latest developments, and how do you incorporate innovation into your clinical practice and research endeavors?

Although there have been many technological and technique developments over the last couple of decades, it is important to remember that the basics do not change! We still have to remember that the aim is to disinfect the root canal system when doing endodontics. The outcomes of root canal treatment have not changed significantly at all since the 1970's and 1980's which is interesting to consider. Firstly, it means that what we were doing back then was very effective. Secondly, it means that the newer techniques do not actually improve the outcomes - all they tend to do is make the treatment somewhat easier and quicker! However, easier and quicker does not mean more bacteria will be removed or die, so this aspect must never be forgotten. You asked how do I keep abreast of developments - the simple answer is that I go to many conferences and I read many journals, as well as discussing things with colleagues and the manufacturers. Then, I take a careful approach!! I am always skeptical - that is, I question the claims that are made and where possible I test or research them myself. I will not use anything new (instrument, technique, concept, etc.) on a patient until I have satisfied myself that there is an advantage to the patient and the treatment outcome, plus I must ensure that it is safe for the patient. We should all be practicing evidence-based endodontics and we must ensure that what we think is "evidence" is truly scientifically based and proven evidence.

In your experience, what are some of the most challenging aspects of diagnosing and managing pulp and peri-radicular conditions, and how do you approach these challenges to ensure optimal patient care?

Diagnosing pain can be challenging although pulpitis and apical periodontitis is relatively easy to diagnose if the clinician gathers all the information that is needed. Unfortunately, many dentists do not do this - for example, many do not use pulp sensibility tests, they take inadequate radiographs, etc. If you have all the information, if you understand what each test is telling you, and if you understand the disease processes, then diagnosis is not too difficult. Sometimes it is more difficult to locate the source of the pain if the patient has poor localization. Management of some conditions can be very challenging. For example, if there is persistent apical periodontitis after root canal treatment, the decision on whether to re-treat the tooth can be difficult. Endodontic retreatment is a major focus of my clinical work and research, and although retreatment can usually lead to good results, the dentist has to make a careful assessment of the factors that have led to the persistent disease, as well as the likelihood of successfully rectifying these problems. If you do not know why the tooth has not healed, then the chances of success for retreatment are low.

As an Officer of the Order of Australia, you've been recognized for your distinguished service to clinical dentistry, higher education, and professional organizations. What motivates you to continue contributing to the advancement of dentistry, even after achieving such prestigious honors?

Receiving the Officer of the Order of Australia award was definitely a real highlight of my career - and a most unexpected accolade, especially because it came from the community and not just from within the profession. Receiving this award actually motivated me to keep going and to do more for our profession as I met other awardees and I was inspired by the things that they have achieved. I have also seen that these people keep on giving themselves and their services to their respective professions and/or the community. The award also opened up opportunities to meet members of the dental profession who had received similar awards and that was further inspiration for me. I also believe that the award was not just recognition of my work, but it was also recognition of the work of everyone who had worked with me or supported me over the years - especially my family, my students and other colleagues. They provided inspiration both before and after the award was announced.

Based on current evidence and advancements in endodontic practice, are there any traditional methods or approaches to root canal treatment that you believe should be discontinued immediately?

No, I do not think we should discontinue any of the traditional methods of root canal treatment at this stage. As I mentioned above, the newer techniques and devices have not led to improved outcomes for patients, so the traditional methods are just as valid today as they still produce the same outcomes.

It is also important for undergraduate students to learn some of the traditional techniques - such as hand filing - because it helps them with the development of their hand skills, plus rotary instruments are not applicable for all cases.

Similarly, some root filling techniques cannot be used in all cases, so traditional techniques such as lateral condensation are still applicable to many cases. Irrigants and medicaments have not changed and are still important. New devices make some things easier and quicker, but no research has shown them to make treatment better or more predictable as this still depends on disinfection of the root canal system, and instruments do not disinfect the canals - all they do is enlarge the canals and help to clean them of gross debris. Students should still be taught the basics with an emphasis on understanding the disease processes, diagnosis, treatment planning, the treatment aims, and the general concepts and philosophies of the treatment approach. The technical aspects are just that - i.e., techniques! I believe the biological aspects are far more important and these do not change with "technology."

What are your thoughts on the current state of vital pulp therapy techniques such as pulpotomy and direct pulp capping, in terms of their success rates and long-term outcomes?

Interestingly, these techniques have become popular in recent years. They have had previous periods where they were popular, but it seems that they are not readily accepted by the profession overall. Endodontists have been advocating these techniques, but general dentists do not appear to be convinced! It is important for general dentists to understand that these techniques are viable with good case selection. General dentists will likely see many more suitable cases than Specialist Endodontists as the general dentist is where patients typically go first. Case selection is extremely important with one major factor being the amount of remaining tooth structure because sometimes I feel that root canal treatment may be the best long-term option when comprehensive and expensive restorations are required. However, the concept of preserving the pulp is one that we should follow wherever possible.

Looking ahead, what do you envision as the future direction of Endodontics, and what areas do you believe will be the focus of research and clinical innovation in the coming years?

It is always difficult to predict the future of any clinical discipline as things can change rapidly. However, I think there will inevitably be continual work to develop the technical aspects such as root canal instruments because this is largely led by the manufacturers and suppliers, and they will always have a commercial interest to advance their products. From a biological viewpoint, I hope that research work continues on disinfection agents such as irrigants and medicaments. I also hope that research continues in dental traumatology and tooth resorption as we still have lots to learn in these areas.

Are current methodologies of Endodontics (complete pulpectomy and gutta-percha obturations) still going to be relevant for the future, or shall we be embracing Regenerative Endodontics entirely?

I believe that the current methods of managing pulp, root canal, and peri-radicular conditions will be with us for many years. I say this because true "pulp regeneration" is yet to be shown to occur in human and animal teeth despite about 25 years of research and clinical case reports.

Unfortunately, the term "regeneration" is very misleading for what is currently happening with the so-called "regenerative" techniques. The word "regeneration" is defined as getting back the tissue that has been lost - hence, it is inappropriate to use.

It is also not revascularization - that is a process that we have known about for decades following trauma - such as an avulsion - where the blood supply is cut off during the injury and then after the tooth has been repositioned, the blood vessels re-anastomose with the pulp tissue that is still in the canal. The pulp then recovers and functions normally. A more appropriate term is "repair" because all we see is repair of the periapical tissues - which should be expected if the root canal system is adequately disinfected. There may also be repair with various soft and hard tissues within the root canal - but no research has shown that pulp develops at this stage. Currently, we do not have a predictable protocol for this "repair" treatment and the longer-term studies (i.e., more than 2 years follow-up) are showing more cases of continued or new infection of the root canal system. Many of these teeth will then need to be extracted as endodontic re-treatment is not always possible because of the various hard tissues that form in the canal. At this stage, I think this is still very much an experimental procedure and much more research is required. I am also concerned that this unpredictable procedure is being done on young patients who may lose their tooth. I believe long-term apexification with calcium hydroxide is still the simplest and most predictable procedure for an immature tooth that has an infected root canal system.

You have also been a part-time private practitioner. What have you enjoyed more: private practice or academics?

I enjoyed both - equally!! As I mentioned earlier, the first half of my career was mainly private practice with part-time academic work. Then, the second half was the opposite. As a clinician, I believe the academic work helps you to develop your thought processes and to recognize what areas of clinical work need research to justify what we do or to develop new ways to do things. As an academic, the same happens but in reverse where you are better able to do the research and then you can apply it to your clinical work. Overall, what I have enjoyed is having the variety throughout my typical working week. Each day was different. I also enjoyed being able to interact closely with specialists in other disciplines of dentistry and this is much easier to do as an academic than when busy in private practice. Finally, interacting with students can be very stimulating as they question what you say and make you think. They also tend to have much more respect for an academic who they know is doing clinical work as well. Hence, I have enjoyed all aspects of my career and the challenges that they have presented.

What are your top 3 book recommendations in Endodontics?

My top recommendation is what many people call the "trauma bible" - that is, the textbook by Andreasen, Andreasen, and Andersson on Traumatic Injuries of the Teeth - now in its 5th edition. Every dentist should have this book, no matter what discipline they work in as trauma affects all areas of dentistry! My recommendations for Endodontic books are *Ingle's Endodontics* and *Pathways of the Pulp*. I also recommend a new book edited by Ahmed and Dummer called *Endodontic Advances and Evidence-Based Clinical Guidelines*.

What are your top 3 journal recommendations in Endodontics?

I think that every clinician who provides endodontic treatment should be very familiar with the management of traumatic dental injuries - hence, I highly recommend *Dental Traumatology* as a "must-read" journal in addition to the specific endodontic journals. Then, I will take the liberty of recommending four journals for endodontics - the *International Endodontic Journal*, the *Journal of Endodontics*, the *Australian Endodontic Journal*, and the *European Endodontic Journal*. I also recommend that clinicians read widely and have email content alerts for other journals as some of the general dental journals can contain very useful endodontic articles from time to time.

Lastly, if you could sum up your philosophy or approach to life in general, what would it be?

I strongly believe that we must do the things we enjoy and enjoy the things we do! This applies to all aspects of life. In addition, family comes first, followed by friends, and then work. I also adhere to the philosophy that what you get out of life depends on what you put in - hence, I have always been very happy to give my time and energy to helping others whenever I can. As a healthcare practitioner, this can be easily done through managing our patients, but we should all go beyond this and contribute to society in other ways. This could be through donations to charity, doing charity work, pro bono treatment of disadvantaged people in your area, education, helping with your children's sporting activities, plus many other ways - the opportunities are endless! As dentists, we are very privileged, and we must always appreciate that others are not as privileged as us -but we can help them in many different ways. Once you find a way that you enjoy, just do it!

Thank you for the opportunity to talk about all these things.

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