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Welcome to the Ruddle Show. I'm Lisette and this is my dad, Cliff Ruddle. How are you doing this morning?

I'm doing great and I'd even be doing better if I would have done that first.

So we started talking yesterday about if we were going to do any summer vacation. You maybe remember our Hawaii vacation we showed you last year. But right now we have no vacation plans because we didn't make any in the last couple months. In the time of Corona Virus like what do you do? A lot of people are renting motor homes; that's up. I guess camping is a good option. So we started talking about our past camping trips, because as a child we went camping a lot. And a lot of times while we were camping we went on these pretty amazing hikes. So we started talking about hiking more than camping, and we thought let's share some of our hiking experiences with you when we open the next show. So why don't you tell us some of your great hiking moments?

Well, I think we're laughing because she knows one of them is going to involve her. Well the first one I'd like to talk about that was pretty exciting – it was some years ago and we were camping on the south shores of Lake Tahoe. And for those around the world that have never been there, it's one of the great wonders of the world in my mind. It's a fabulous lake. I don't know that they've almost ever found the bottom of the lake, so it's a very deep, beautiful, emerald blue lake and it has a ring of mountains around it. And the centerpiece, the queen of all the ranges and mountains circling this lake is Mount Tallac. It's actually pronounced T-Lak, but Tallac is how I say it.

So anyway, Lise and I left our campground – do you remember this – and we got in the car and we went up about 2 or 3 miles and we parked. And I'd seen that sign every day we had driven back and forth to Aspen, and I said – we actually didn't have a plan.

Were Mom and Lori with us, and then they didn’t want to hike and we thought oh, we're just going to hike a little bit and they went back and we went hiking?

They took the car. They actually dropped us off because they didn't want to be car-less for whatever period of time. So we got dropped off at the trailhead, which is right by the lake, and I said to Lise we're going to climb Mount Tallac; would you like to do that?

Well I think you said well let's just go a little ways. Let's just see what it's like. Because we had no backpacks with water or any food or anything. We were just going to scope out the bottom of the trail.

That's true. I said maybe we could just kind of check it out, the bottom third or whatever. So maybe I should tell our viewers that it's – from European standards or maybe Alaska – these maybe aren't massive mountains. But it's in the United States; it was 9,700+ feet. So I don't know what the meters are, but it was almost 10,000 feet.

It was like 5 miles to the summit.

Well it was 10.2 round trip, so you're about right. So we started climbing, and it was a nice trail as I recall. We soon were in trees and the forest. And as we gained elevation, we went by these incredible lakes; I don't know if you remember. There was Fallen Leaf Lake and there was Meer Lake and there was Cathedral Lake, and we were going by these little lakes looking down on them because we were on a ridge. And when we finished the ridge, there were these cairns. I don't know if you remember, but for our viewers that don't hike, they're little rock monuments that are trail markers. So we were following the cairns and we went around the corner, and then we could see way up the mountain to the peak. And I asked you, what do you think?

And then I said it looks so close; we're almost there; let's just go a little further.

So she was pretty young then, and just so you'll know, we were probably a third of the way. So I said well maybe we don't have to get to the top, but maybe we could just go about this far again. Well we went through meadows and there were incredible flowers and it was springtime the way I recall; anyway there were flowers. And just intoxicating views across Desolation Valley because that's where this mountain range is around the lake and that's Desolation Valley. And finally we came to a bunch of really massive boulders. Do you remember that?

I don’t remember the details of it. I just remember the conversation being let's just go a little further. Let's just check it out a little bit more. That's all I remember really about that hike until we were at the top.

Well long story short, we were above the timberline, so we were crawling across rocks and kind scrambling and we got to the top. And I remember when we got to the top it was a tremendous sense of accomplishment. I looked at my daughter and I thought no water, no sunscreen. But we're here and we weren’t struggling. She didn't say one time to me “I'm thirsty!” You didn't complain ever. Lise was a phenomenal hiker. So that was a really good experience and it brought us down off the mountain some hours later, because it was 10.2. It's considered a very difficult – if you look at the ratings, it’s very difficult to strenuous – so that's what we did. And it was a great place to have magnificent vistas, beautiful skies, changing color. It was a great memory I shared with you.

Yeah, I do remember. Remember when we were at the top we only saw that one other person? And they actually asked us if we had any food or anything to eat because they said that they were a diabetic and they might be in trouble.

I do remember.

I don't know, that seemed a little bit scary. But then they just walked off.

Yeah. I think what you should hear from what I'm saying is be prepared. And we started off on a little innocent walk that turned out to be a little more of a walk that turned out to be a complete, full-blown hike. But it was a wonderful payoff and we've often talked about that over the years.

Yeah, we often talked about how we could go on such a massive hike with absolutely no water or supplies or sunscreen or anything.

Next time a knapsack.

And then you also went on that – I didn't go on it, but you went with Mom and Lori on that High Sierra camping thing. I don't know if you want to say a little bit about that, but it sounds pretty fun.

Well I'm trying to get her to do this too, but any of you can do this, but it's a lottery so it's not so easy. But it's called High Sierra Camps, and there are seven camps. And we went – if you're in Yosemite Valley you just take Tioga Road and go up out of the valley, and you go up to Tuolumne Meadows and that's where we started; that's one camp.

So we hiked – it's about a day – we hiked into Glen Aulin, and there's tremendous waterfalls. All these High Sierra Camps are about 6-8 miles apart. You come in at night; you have a concrete slab, bunk beds, bedding, hot showers, wonderful meal. And breakfast is terrific, it's a send-off breakfast; they give you a -

Sack lunch.

Sack lunch goes in your knapsack. So you only carry a day pack. You carry lip balm, you carry sunscreen and water and your lunch, and that gets you to the next camp. And the next camp is always 6-9 hours away depending on how fast you walk and if you stop and all that. But anyway, we went to May Lake. And at May Lake, it's a fabulous lake and in the lake you see the mountain we want to hike. It's mirror in the lake; it's May Lake and it's Mount Hoffman.

So Mount Hoffman, it's 10,800 feet so it's a little bit higher, about 1000 feet higher than what you and I did, but that time I had Lori. So we started walking off in the morning – got up early, had the breakfast – and we took a lay day so we weren't going to the next camp; we were going to take a lay day and do the hike. So we went up Mount Hoffman; a similar experience; fabulous hike. A little bit shorter, it was only – it's 6.2 round trip; it's strenuous; it was four hours so about two up – probably three up and one down, something like that. But beautiful. You're looking all over Yosemite. You can see Half Dome; you can see some of the great – Glacier Point – you can see some of these outstanding, internationally known monuments, and you're right up in these peaks; they're like the peaks of the gods.

So the thing that Lori remembers the most is like you, we broke out of the trees and the meadows and we got to kind of like the last ascent, and there's a false peak. So when you're down here, you're coming around, you see this peak and you know that's the top; but when you get there you realize there's a taller one. And you have to go down in a little bowl, and then the last part's a scramble. And Lori was a little bit afraid, but she stuck it out. She was a little older than you at that time when we took our hike.

And so anyway we summited and we stood up there, and we could see our campground down below and the lake, and we could look at all the beauty. And hiking, I think to come back to the big picture, getting away and have a breakout in your mind, it really does free up your spirit and your soul to think about what's possible.

Yeah, it's true. It gets you thinking. But one thing that I've learned from all of the hikes we went on is that when you think you're close to the top, it's usually much further than you think still to go. That's one thing I've learned hiking. So we're probably going to do a lot. I mean actually Santa Barbara has a lot of great trails around here and I think we're probably going to do some hiking this summer as a family. I mean you can do some hikes, too. I do think though, with Santa Barbara having all the fires recently that a lot of the trees have burned down that give you shade on the trail. So you definitely need sunscreen and you definitely need to bring a lot of water. But yeah, I think actually even if we just stayed here we could probably hike every week on a different trail for the whole summer; there are so many trails around here. Maybe even every day.

And to tell you out there, she hikes a lot in Santa Barbara. So she's taken me on one hike here a few weeks ago; even back when you were even littler we used to go to Cold Springs Canyon and on up through the trail there to the lake and water.

Yeah, well we could talk about hiking actually for an hour, but we need to get started with the show. So let's get going.

In 2001 one of the most game changing file systems came to market, and this file system has subsequently revolutionized modern endodontics. And in case you can't guess what file system I'm talking about, I'm talking about ProTaper. Today we're going to discuss how the concept was conceived, what makes this file so unique, and then look at how it's progressed in its journey of 20+ years.

Now you're one of the inventors of ProTaper, along with Professor Pierre Machtou and Dr. John West. And because this represents a success story of the highest caliber, we often get questions from clinicians wanting to know how it all got started. So let's tell them. Let's tell them how it all started in Singapore.

Wow! You know I've never really told the ProTaper story and at least from my perspective, it's quite a story. But I think I want to just first say thank you for allowing me to do this because we do get a lot of questions and they want to know how it all happened. So here you go.

So the year was about the mid-'90s and I was on a lecture swing through Southeast Asia, and the first stop was Singapore. And so we stayed at the Raffles Hotel; it's a lovely hotel because -

This is the hotel.

And it was a lovely hotel because it was all the British theme and wicker furniture and the fans were blowing; because you know Singapore sits almost on the Equator so it's – there's not a lot of temperature – it's like 99° in the daytime, at night it's 92°.

So anyway we met there and Mark Oliver, the guy you see in the photograph by me, he was one of the owners of at that time Tulsa. It then, for the viewers, was Tulsa Dental and it became Tulsa Dental Specialties, then it became Dentsply Tulsa Dental. But anyway, he was one of the owners at the beginning. And one of his partners was a guy that everybody knows about in the world, Ben Johnson, the entrepreneurial inventor. So Ben did many, many fabulous contributions.

So Mark said, “I'd like to have breakfast with you. It's a lay day tomorrow and then you start a very grueling schedule, so he said let's have breakfast; I want to make a proposition.” So at breakfast Mark said to me, “You know, Cliff, we're thinking about developing a new file and we'd like to know if you'd join the team.” And I said, “Team? Who's on your team?” And he said, “Well, this is an idea that Ben got from Dr. John West.” So he said, “John West literally on a napkin drew his design and Ben still has it, and the company thinks we can go ahead and do this.” So he said, “How does that sound?” And I said, “Well it sounds interesting to me, but I would like to be really rude and invite one more person.” And he said, “Well who would that be?” And I said, “Well, you've got two Americans, but I think we need somebody overseas; somebody that has a lot of respect, somebody who's well known, who's a fabulous, gifted clinician, and in this case an academician, Professor Pierre Machtou.”

I think we have some pictures maybe.

So anyway, long story short, it all started at the Raffles Hotel. Nothing happened for some weeks, but then I want to say a little bit about John. John I met in grad school. He went to Boston University; his mentor is in the middle. Nobody's ever heard of Dr. – Professor Herb Schilder. He's probably the father of modern day endodontics. So that was – he was the mentor for John West.

Herb Schilder, he trained my guy. My mentor was Alvin Arlen Krakow and Alvin Arlen Krakow was in the second class. So the reason we're showing here – this is 1995 – it's about the same era that we started the file project. But mainly John and I have known each other since '76, so that's when we were in Boston as residents. So that's John West and the beloved Herb Schilder.

And then I got an invitation in 1987 to go to Paris to give my first big international lecture – there were hundreds of people there – and it was called Societe Odontal G de Paris. So Pierre Machtou was not president of SOP, but he was the program chairman and he had asked me.

So there you are; 1987, we're on the front row and we're getting ready to – I'm going to go on in probably about 30 or 40 minutes, so Pierre is giving me some sage advice I'm certain. And then we have a little inset of him at the school – Paris 7 is the most important dental school in France – and so I'm really proud of Pierre. He was the Chairman at that school for decades.

I love this picture. When I look at it I just wonder what you guys are talking about. It's really a great picture.

So those are the players; we've now introduced them.

Okay, so the team was formed and you all – like you, Pierre and John, all great clinicians, published regularly, great speakers – so it sounds like it was a pretty ideal team.

It was. And so the audience knows, I might have known Pierre better than John. Because after SOP in '87, we were in regular communication – regular – and exchanged cases and ideas and concepts. John I knew by reputation, and although we banged into each other at a few meetings around the world, I never really just sat down and visited with him. So it took about 20 years after grad school for us to come together like we're going to see.

And you affectionately call yourself The Three Amigos. I think that's funny.

We have been called the Three Amigos.

So when did your first all get together and start working on the project?

In 1995, and it all started right here. As you can see, that's the plant. Ballaigues, Switzerland is a little village of less than 1000 people in the Swiss Alps. So you fly into Geneva, you take about a one and a half hour car ride to Yverdon and we stay in Yverdon and then we come up that highway that you can see every morning early. It's about 30 or 40 minutes to the plant, and then we arrive at this facility. So the facility is layered across the hillside; that's the cafeteria, the very bottom building; machine plants and there's machine plants all the way up. And then we'll get another perspective. If you look from up the mountainside looking back, that's kind of how the building looks when you drive in. And don't be fooled by the architecture. Inside, it's state of the art, because it kept the old world look in the field as we'll see shortly; but inside, everything is renovated. Inside here you have white collar people working marketing, advertising, CEOs, general managers. But they give courses in this building right here and Daniel Nobs, we'll meet later, he has people from all over the world come and train here. And they've trained I think – I'll just say many, many thousands of international dentists trained right here at the facility.

Okay.

Now for some of our viewers, they might appreciate that it didn't always look like this. So let me take you back to 1889, and August Maillefer, that was the first guy; he was a dentist and he began in 1889 making a few dental instruments for the dental profession, and some medical instruments. And in fact last year they just celebrated the 130th year anniversary.

But what I want everybody to know with this very modest picture; Maillefer was a clock factory for many, many decades prior to being a manufacturer of dental instruments. So they made clocks, but they kind of converted over in 1889. So don't be deceived by that; the current factory makes one million files per day. There are 750 people that work on campus and they are known all over the world as one of the finest machine companies. Maillefer makes their own machines; I want to make that distinction even with you. A lot of companies go out and buy machines. They make the machines that make the machines. So because of that, they can do very innovative machining and they can do tough designs that are hard for other companies to make.

Well we all came together, so I'll just say on the back row you can see Daniel Nobs on the left, a younger version, but he is head of international education. So he was planning with all the conferences around the world, the major state and country meetings, for speakers; and getting meetings together and of course funding those meetings to make them happen for dentistry. To his – to our right is the head engineer, Gilbert Rota; he also has been on the Tour de France as a grease monkey, so we love to talk to him about his experiences. And to his right is head of marketing, because why is marketing in this picture? Because marketing tells us all the things that dentists are complaining about, the things they don't like. So we have to introduce these things they don't like into innovations and improvements on future innovations. And then finally, our spiritual leader, Pierre-Luc Maillefer. And you know it was August, it was Michel and then it was Pierre-Luc, but all the Maillefer name. So a long string of leaders. And so Pierre-Luc was our leader and he challenged us to have an idea, to blow the lid off it. He said we're not going to make another Mi-2 file. We need to do real innovation.

So it all starts with a plan, and after big discussions among our group for hours and talking at night and over dinner and at breakfast, finally you get a rough plan together, the engineers then execute it with the machine shop, and what we ended up with is something that would be like this. So what I can tell you is flexibility. We wanted to make instruments that were really flexible to crawl around curvatures and re-curvatures. And we could do that with progressive tapers.

Pierre always loved the Eiffel Tower, because every time he looks at the Eiffel Tower – he's Parisian – he sees ProTaper; because the structure as you know because you lived there – she lived in Paris – it has multiple changing tapers over its length. So Pierre really liked that. So by changing the taper though it deactivated the instrument, so it minimized its contact between itself and dentin. So if you have longer engagement zones, you get a screw effect. If you have shorter engagement zones, you have a more efficient, smooth, progressing instrument.

And then our cross-section was a convex triangular, and you can see that. And that was a little bit innovative because it was the first active instrument in the world. Rotary came to market about 1992-93; remember we're here in '95. Everything was radiolanted with U-blades, so we were the first instrument in the world to have an actual cutting edge. And then another thing we did is we shortened the series. Most series in the era were like five or six instruments. We basically said it's as easy as 1, 2, 3; purple, yellow – sorry – purple, light yellow.

Okay, so that's a little bit about what we were trying to do. And then of course we didn't even know the word “minimally invasive endodontics,” but if our audience would look at Pierre and John's idea now this is the whole essence of their idea. All files before this were fixed tapered. So if they were 2% every millimeter you went up the instrument 2, 2, 2% fixed tapers; 4% fixed tapers; 6%. Well as you get to bigger tapers, those instruments want to screw. So how can you have bigger tapers, because our yellow instrument – we had yellow for a finisher, it's a 20/07, and our popular one is a 25/08 – but those are big tapers.

So their idea was to have a regressive taper file. So if you look at the top, you can see that's a 25/08, but the back end is only 1.05. We could say the back end is 1mm, so more or less it's a human hair difference, so it's about a millimeter. If you ran 8% Lise, out over that 16mm you'd have a staggering 1.53. So we wanted to make instruments that were more respective of dentin in the body of the canal, but still give colleagues the deep shape; because the deep shape could not only be three dimensionally disinfected and cleaned, but it could be filled in three dimensions.

So that's a little glimpse of the files.

I wanted to say one thing just to be clear. You had said that John had the idea of the progressive tapers on a single file that he had written on a napkin and given to Ben Johnson. But at the same time over in France, Pierre Machtou was working on something and he had even showed some prototypes to you, also progressive tapers on a single file. But they had not had communication with each other, but this idea was emerging simultaneously in two different locations; kind of like the pyramids in Egypt and Mexico.

Oh interesting!

So when you guys all got together, you already had some idea of this whole progressive taper thing.

Well I wasn't going to get into this, but Pierre will be very happy that his good friend Lisette that stayed in Paris for quite some time brought this back up. Unbeknownst to John West, in about '92 and '93, Michel Maillefer, at the time the general manager, he came to him and he said we need a new file because the first iteration is kind of crude, the U-blades, the radiolans, the profiles if you will and the GT files. And he said we want to get way more innovative, we want a shorter series. What would it look like; would you know how to do that? So Pierre said to the main engineer at that time, Francois Aeby, he said yeah, the tip would be about a 25. And up here at the orifice level it would be about 1.1, 1mm. And Francois the engineer immediately said, “I can do that.” Pierre said “No, no, no, you can't do that; because if you make that a fixed taper over all those 16mm you'll have a stiff screw.” Pierre said, “You must change the taper. Francois, you must change” – can you hear him – “You must change the taper!”

So anyway it came out to be flexo-taper, which was actually machined and made. In the lecture in Bello Horizonte, Brazil, many years later Pierre brought me some – still in the '90s – and he gave it to me and I still have it. So it wasn't an idea; it was an actual, physical file that he was using. Phyllis reminded me that I had actually worked on that file myself. But I am not taking any credit for progressive tapers; although I played with flexo-taper and helped refine it we can say. I actually did do that. It was really John and Pierre that are the fathers. And to your point, two guys maybe 12,000 miles apart, more or less at the same moment in time both conceived the same idea.

And it's also kind of serendipity that Mark Oliver asked you, and then you wanted to bring Pierre who also had the idea. So it's like -

Maybe it was logical?

Yeah. It's a little more than coincidence.

All right.

So let's see. So all of this is when you started working on it. Did we go through all of the factory? I think there's more.

We can go a little further. You kind of wanted to know what was a typical day I guess and how it all started. So I don't think the audience wants to hear too much detail, but we were up very early in the morning. A van would pick us up at the hotel in Yverdon and up the mountain we went. And as we drove up that mountain – can you imagine the hiking, how you felt? Did you get a high; a little buzz? Because we were going to do something really important today. We were going to change the world. That was our command from Pierre-Luc Maillefer.

So we would get up, go into the plant, and there would be brand new instruments sitting at each station – the ones we'd been talking about by email or fax or whatever it was in that era – and there they were. So we'd go to work. And while we were working, the machines were making some refinements already, because we would say hey; this is like – it's a little bit stiff in the second curve; we need to make the instrument a little more flexible; we need to reinforce the back end; all these little ideas.

So there's a shot of the factory and you can see some of the machines. And then of course, we would then try these and we would try them endlessly. So we would spend hours, first in plastic blocks, because plastic is very unforgiving with files. Files get really grabby, so you have to have a really balanced instrument, balancing safety and efficiency, to work in plastic. And I'm not talking about this. I'm talking about 90° curves in plastic and I'm talking about 40° and about 40° re-curvature in plastic. So we always know if a file works in plastic, it's going to be beautiful in dentin.

So we worked plastic and then we started working in dentin. But then guess what? It dawns on us that we need to make refinements. We need to make some changes because we've discovered – one of us did, two of us, or all three of us. And so we would have breakout sessions, talk to the engineers; and they would get into our heads, we'd get into their heads. I loved this because we were learning a lot about instruments and how they work.

So it was quite normal then to have breakout sessions; the machines would go back to work. And every year we went back there were more machines because when we first went there there were no machines; it took a long time to get prototypes. Then they made one dedicated ProTaper machine that could make six ProTapers. I went back another year and they had six machines, one for each file; Shaper-X, S1, S-2, F1, F2, F3. And then I went back later and there were over 100 machines; because they'd run 24/7, three shifts a day. So more machines for tweaking our instruments. And then the thing I loved; being a clock company, the precision is demanded; it's expected; it's a part of who they are; it's in their culture – clocks.

So anyway, you can see some of the shots. I won't try to explain them, but I think you're getting a sense as an audience that there's a lot of workmanship and craftsmanship that goes into these, and the engineers are really smart people.

And then finally the clinicians don't want the engineers, we don't want marketing around, we don't want education around; we want talk: how is it really working? Are you excited about it because I'm excited, or do you have some misgivings? So all that has to be flushed out in very open, honest way for the integrity of the result.

So that was kind of a typical day, and I just mapped out actually the typical years as they flew by; because we went every year from 1995 to 2012. Every single year. And I went after 2012, but for other projects.

Well you started in 1995, right?

Yes.

That was the time – or maybe that was the first time you went there to work on that project.

On that, yes. Because I had gone there actually in 1991 to work on some other stuff.

Okay, and so 1995 was a pretty pivotal year for you. So just remind us really quickly what happened in 1995.

Oh, because I probably said in a previous show. It was a tough year – not to whine – but my mom passed away; we were pretty close and she wasn't that old, 76. So she passed away. And then I was in Italy giving a lecture in Florence for Professor Arnolo Castolucci, who you also know; you stayed in Florence. She's quite the traveler! She just didn't have her lecture carousels or she would have been a Ruddle, too. Anyway she was in Florence and we gave a congress there in Florence, and Arnolo was a good guy and that was all part of that story.

Well yeah. I guess what we want to make clear is that was when you had the detached retina, and your practice was kind of put on hold.

Well I didn't want to go into that, but she's forcing me. Okay. So when I was giving the 3-day lecture for Arnaldo Castellucci and there were several hundred colleagues present, in the middle day my eye started flickering and doing weird stuff, and I thought it was a bad contact. So I went to bed that night late, didn't think much about it; got in late, got up really early. The next day, the last day, a curtain came down and I couldn't see. I decided to do the third day because I had all these people and I had accountability, responsibility, so I did the third day like a stupid person and then it takes a day to get home. And then I had a scleral buckle; it's a band like a band that goes over your tooth. It's a band that goes around your eye so they can approximate the retina with the back of the eye and then they laze the Hell out of it; and I was out for about a year.

And you know I think this is interesting because as you were forced to stop practicing, this other door opened up for innovation and going to the factory. So it's just kind of how opportunity works. I thought it was interesting how when one door closed another door opened. And you just have faith and you just take your new path, and you were doing something very creative, creating something. So I think that's really actually interesting.

As I understand it, you actually had finalized the file that you thought was ready to launch around 1998. But it didn't launch until three years later in 2001. So what was that delay about?

Well fortunately, there's no politics in endodontics. I mean if we want politics, we just watch a little television and do a little reading, but there's politics, believe me, in endodontics. We were kind of pushed on the back burner because Dentsply at that time had acquired Tulsa, and they were really going hard on Pro Files and GTs; those were two of the most popular files in those days. So you can begin to see; we were trying to move in with the big boys. Those were big, name brand files that were taught and sold around the world. So we had to wait because they didn't want the competition to be frank, so we were blocked for a while until 2001.

Was this discouraging for you?

Well actually we weren't discouraged; it's kind of funny. You'd think we should have been discouraged, but I guess we were too young to know better. We were thinking business. We were thinking every year I get to go to Ballaigues; I get to spend a week with my friends; I learn so much from the engineers; I talk to Nobs and learn all about education, new ways, teaching models and all that; we're brainstorming at night. We were happy and thrilled and we didn't know what would happen, but at the very least, we were making a file I could use, they could use; and we could teach it, too.

I heard you say earlier – you referred to Pierre-Luc Maillefer as your spiritual leader. So how did he fit into all of this?

Well Pierre-Luc is a stud. You know he's a little cigarette; he's very thin and short; he's brilliant; the whole Maillefer family was brilliant. But inspiration was he would go up the mountain in the Swiss Alps on a dirt bike. We would drive up in a van to a restaurant at the top of the mountain; he would ride up on his bike and meet us. Anyway, he was an incredible guy and just being around him – I could tell you many stories, but he was very inspirational. So when he said do something important, that was what we ate, breathed and slept; we wanted to do something to really be a difference maker in files.

He kept the morale up basically.

He kept the morale up.

Is what I was getting from it. And I think just with the creativity and inspiration you're feeling; just we're having fun doing in and not focusing so much on why it wasn't launching. Like you said, you were learning a lot. I know also that you love documentation, right? So this was maybe something you had done in your practice, like a lot of documentation. And you enjoyed doing that and you did a lot of that when you were doing the R&D.

Well thanks for bringing that up, because people probably think oh, so you spend one week a year; you build a file; isn't that great. No. When you leave the company you have only moved the file closer towards the goal. But then the files arrive in the mail and there's hours and hours of field testing. We do hundreds and hundreds of extracted teeth. And of course notes, documentation, torque stuff, speed, flexibility, efficiency, dangerous stuff; all this has to be flushed out and identified because then you communicate back to the company and more files arrive with little adjustments. So life is about adjustments and building files is about adjustments. And not getting to market is about adjustments.

Yeah, I guess what is striking to me about this is a lot of people when they invent something they think oh yeah; I want to invent something so that I can make a lot of money. And I've actually not heard you even say anything really about – I heard you say that you were hoping to make files that you could use in your practice. So it wasn't really ever I think about inventing something to make a lot of money. I think it was just the whole process; you were just in love with the whole process.

You know Lisette, I feel so honored to be chosen to be part of something that through the teaching of doctors that I train; through them touching their patients I've touched millions of people I never touched, but I touched them through the files we built. So our idea always started with the patient. It was always a patient centered idea. And if the patient wins, then it empowers the doctors to deliver that care and then make the company successful, and we figured good things could happen.

So the good news really kind of broke. I got a call one morning – this was in 2000 and you said you'd been blocked – and it was Tom Whiting who was the president and COO of Dentsply Sirona at that time, or Dentsply/Tulsa Dental Specialty; they hadn't merged with Sirona yet – and at that time, he called me in the morning and he said, “Cliff; we're going to launch!” I said, “Launch? What are you going to launch?” “ProTaper!” I said, “No!” He said, “Yeah, we're going to launch.” And I said, “Why now? We've had it since '98.” And he said, “Well, Steve Buchannan is worried about it.” I said, “Steve's worried?” He said, “If Steve's worried about it, we felt it was a damn good file.” So that was a good story, and then at that time he said, “You'll be hearing Pierre-Luc Maillefer.” And that's when Pierre-Luc Maillefer came to the three of us on one of our trips and he said, “You know guys, we know how hard you've been working for all these years. You've never asked for anything except your flights and your hotel.” So he said, “There'll be some compensation that we're going to reward you for your work; but also go forward with it. We expect great things; we want you to teach more. We want you to write articles and publish.” He said, “Some of you will even start websites and you can have platforms and get it out that way” just like we're doing today.

So anyway that's kind of how that all happened. And so go ahead. It didn't start with a bang though.

Yeah, so it launches in 2001 and it wasn't just an overnight success. What were some of the issues?

Okay, well what Tom Whiting didn't tell me on the phone; he said we were launching and that was the good news. What was the bad news? In life, the good news/bad news story. The bad news was it wasn't even at any exhibit hall; it was under the table. So our colleague – I just heard Ruddle's lecture; I want to see ProTaper! Are you an endodontist? No. Well it's for endodontists only. And furthermore, if you're an endodontist and you came up; do you have ProTaper? I don't see it. Here. Oh! And what's this for? Difficult curved and calcified canals; that's it. It's only for the very difficult curved and calcified canals.

So I started being a little bit negative, which I don't want to be negative – I like to see the glass as half full – but I did whine. I started whining to Russ Vanderslice, one of the co-owners of Tulsa that had been acquired by Dentsply; and I said you guys don't even have it at the booth, there's no marketing pieces, you never show it, and in four years there wasn't one single ad in North America. Think about that. New launch we're really proud of, a game changer; no marketing. Because it's for endodontists only, shhh; difficult curved and calcified canals.

So what came out is he said, “You know what? You need to quit whining.” He said, “I know you're lecturing a lot; you and Phyllis keep a very aggressive schedule.” But he said, “Work harder!” So what's that mean? Well Nobs was head of International Education, so Nobs started putting my sorry you-know-what on the road and I started doing 3-week tours through Asia, Southeast Asia, barnstorming tours through the four Eastern Block countries, Russia, went to Latin America and visited almost every country on the tour. Phyllis didn't recognize me when I came home. I was so old – got so much older. But I always wanted to thank Daniel Nobs who is really not just education; he is one of the pillars of Dentsply and Maillefer. He's been there I think 35 years. So he not only knows all about the history, he knows all about the technology, but he's out on the road teaching. He's bringing the motors and setting them up so the doctors can give their workshops.

So I want to really acknowledge Daniel Nobs. These are a few shots of him from around the world. We're at a stadium in Madrid, at the famous Real, Madrid; national soccer team; and then we're having a dinner in Poland, Krakow, and that's Daniel Nobs.

And as the years went by we did go through different iterations.

Yeah, I think that you were saying that it was in 2006 you made some changes and it became ProTaper Universal. So you kept still going to the factory every year, right, and still working on making it even better. And then as time went by and more changes, ProTaper Gold launched in 2014. So just tell us about what changes the file underwent.

When ProTaper launched in 2001, there were six instruments. And then in 2006 – we went every year, but some years we didn't make changes; other years we were able to make changes. And changes were driven largely by technology and what was available for us to try and use. So machining became more sophisticated, so we could do more things. So the idea in 2006 with ProTaper Universal was to expand the line, so instead of having a 30/09 – that was the last instrument in the set; 30 tip, 9% taper.

The 9% taper though I must re-explain. Remember, regressive tapers everybody. Regressive tapers means that after the fixed taper of 9% in the first 3mm; then as an example it would be 8, 7.5, 7, 6 – okay. So it got smaller to make the instrument more flexible. So they wanted to have an F4, they wanted to have a 40/06, and they wanted to have a 50/05, an F4 and an F5. We got 31mm instruments so we got the longer ones for the really super-long canals like canines perhaps. They added – they extended the line; we have 70 paper points, we had master cones, we had carrier based obturators. Perhaps all of those for me was fluff. The one that was the most important was the F3.

The audience should remember earlier we showed the classic, convex, triangular cross-section. So in every convex side, we made a concavity, a concavity and a concavity. That reduced the core and F3 got dramatically more flexible. So that was what I was most proud of. The extra line was good.

So then ProTaper Gold, pretty much all the same geometry as the ProTaper Universal; it's just now there's new metallurgy, the gold wire?

Also as we're teaching around the world, people always tell you; I love it; it changed my life; you hear all the accolades. I don't want to hear that. I mean of course I feel good about it. I want to hear did you have a problem? What didn't work in your hands that maybe I should hear about; because maybe I can help you fix that.

So we knew with improvement in heat treatment – it was a big thing in this era – Pierre-Luc Maillefer summoned us back to the plant and he said you know what? We can make those instruments dramatically more flexible and we can probably improve the resistance to cyclic fatigue by almost double.

Was it that some people had said that their files broke or something? Is that why?

The complaint was – to be bluntly and brutally honest – our file by 2005 or '06 was the number one selling file in the world. And so I'm telling you a story that's up around 2007 and '08. But listen, it isn't that we had a perfect file – there's no such thing. And so people were saying your F2 and your F3 seem a little stiff. And other companies had started introducing heat treatment, but of course they were making files that were 4 and 6% tapered. So when you have 4 and 6, everything's always pretty flexible; when you have 7, 8 and 9% you really need technology.

So we did heat treatment, so Pierre-Luc summoned us back to the plant and he said guys, let's try some heat treatment. We have M-Wire, there's all this stuff we've been trying, but we have a new idea, new technology, and it was called gold wire technology and it's a post-machining event. So they make all the files, they machine them, handles are on, put them in cassettes; they go up to a proprietary temperature, and then they cool down and it forms an oxide that looks gold, but it can cut and the inside still looks silver like Niti. But that was a dramatic change in our file line, and you can see it right here. So there is an F4 and there is an F5; I've never used them. But if you get re-curved maxillary interiors and you can see those on your schedule, then you might have some bigger canals that need bigger size files. But that's the core set that everybody around the world knows.

So again to summarize this, the fixed taper is only the first 3mm and after that, we have regressive tapers on the finishers. And I never said this until now but our shapers, the SX, the little short one, the one with the purple and the white stripe; they actually have progressively increasing percentage tapers because we wanted those files to work up in the body. We wanted to remove restrictive dentin before we made a big commitment to shape the apical one-third. So shapers worked predominantly upstairs, coronal middle one-third; finishers worked predominantly downstairs, apical one-third, and blend the deep shape into the body.

So how many files have been sold to date, like a million, trillion, billion? I mean I know that Dentsply has had a few clever analogies that have been presented to you, like to try to grasp the magnitude of how many files they've sold. Tell me some of those analogies.

Okay. Well for you, I prepared a special slide, but actually you prepared it for me. Look, I'm really humble about this. But there's an old expression: model success, success leaves clues. It wasn't Ruddle, it wasn't Machtou, it wasn't West. It was a bunch of people that came together to form a team. And we always talk about teamwork, and when you're having a bad day or a good day, the team when they step between the lines, they're focused and they're on. So we had a lot of help with marketing, all the dental reps around the world. But to answer your question; you can read as an audience the number of files sold and it's over 370 million files. So the cleverness for them – Maillefer – the cleverness that she speaks of; if you laid the files end to end that were sold, whether they were 21s, 25s or 31s, it's a pretty big distance. Do you want to yell that distance out for the group in miles and kilometers?

Well 8,311 miles; I don't need the kilometers.

Okay, but if you're overseas, then you might want to see the kilometer number. But anyway, if you put these files end to end – there's fun places – you could go from Ballaigues in Switzerland – maybe think Paris – all the way to Maui. You can go to Western Australia, like going around the world the long way; go to Western, that's out there where Perth is – not the East coast, the West coast. So it's pretty interesting. And then another guy, an engineer there, said well that would be a lot of weight. So each file weighs I think 4 ounces roughly. And if you multiply the 370 million by the ounces, you have something like a lot of elephants.

Yeah, 22 African bush elephants.

And how much do they weigh?

Seven tons each.

So if you have seven tons each, for the foreigners that's 14,000 pounds, we have a herd of how many; 22? I can't hardly read.

Yeah, 22.

Okay, 22. So anyway, fun stuff to kind of in different ways look at how many instruments have been sold. We're humbled and honored. When we started, there might be less than 5 files on the market in the world in 2001. There were GTs and Pro Files, and McSpadden had a pretty good file, and maybe one more. If I'm wrong, say 5. Today, there's over 100 file systems. We have been the number one sold file around the world from about 2007 to present. That's a long run to be number one.

And let's be clear; the story is not over yet, right? Can you give us a sneak peak of what's to come?

Oh, because you saw I just came back from Maillefer again? Yeah, we recently had another great meeting in Maillefer because endo never sleeps. You have to incessantly be working on improvement and working on your product. So all I can say, Lise, in closing; we are working on a new ProTaper. And it is going to be unbelievable. With technology and our ideas it's going to be even more appreciative of minimally invasive. We did a minimally invasive file before the words were even out, but now we can even be more minimally invasive in the body. We're still going to give callings the deep shape they love because that's the shape they can exchange reagents and clean root canal systems, and that's the shape that lets you fill in three dimensions; the thrill of the fill. Got to clean them to fill them.

So we're doing that; it's going to be a shorter series.

What's it going to be called?

Well, I can't really tell everybody everything or my life could be in trouble. But let's just end the show by saying we're going to have something really fun for you next year!

Okay, well I think you even have one more click to do.

Do I have one more?

Yes - top secret.

Top secret; okay.

Okay, well thank you for sharing that story. I actually really love that story; I think it's an exciting story. We're going to be joined for the next segment by Dr. John West and Professor Pierre Machtou, and they're going to share a little bit of their perspective on everything; we're going to do it by Zoom. And so we'll get their perspective, maybe hear some of their memories, and then also find out what went on behind the scenes when no one was watching.

And you know what? That's going to be pretty interesting for them, because I know you know one of those stories they're going to tell; Pierre Machtou's story.

Okay, well thank you. That's the end of the segment. [Music fade out]