212 Drummond

Does new technology in dentistry really work for people?

 Part 1

In Dentistry @ Ballarat we are all about using new technology to do what dentists have always done, but better than before. But using new technology comes with a trap that gadget enthusiasts can easily fall into, falling for marketing hype (think Power balance band). Sometimes the new thing is just the old thing but “Now, with Factor X!”. In dentistry we must always remember that we are working with people and that for technology to be considered useful it should pass the only test that matters: the results it brings should make a difference to peoples’ quality of life.

Dental technology during the 20th century had advanced from the 1900’s but in a few respects had significantly failed to improve the lot of patients’ lives.

An uncle of mine was a minister in the Anglican Church, somebody who loved to talk and meet with his parishioners. On the day that I qualified he took me aside and told me that his greatest fear in life was standing beside an open grave giving an oration and the dentures flying out of his mouth to land with a rattle on the lid of the coffin. He then asked me if dentists had come up with anything that could be used to fix false teeth permanently into the mouth. All I could say at that time was, no, there was nothing really good. New technology in dentistry came too late for my uncle but all that was about to change.

 

Part 2

So what was it like when Brian and I qualified?

Routine dentistry involved filling a tooth with silver amalgam, if it was a back tooth, white if it was a front tooth. If you had a missing tooth you had a denture or a bridge.

Dental amalgam is a pretty good material at plugging a hole in a tooth but you can’t escape the fact that it makes your teeth look black and it is a material that, if it hasn’t been replaced early because of decay infecting the tooth around it eventually it breaks down, becoming rough and attracting plaque. When amalgam deteriorates it expands and has the potential to crack cusps. Cusp fracture is one of the most common reasons for tooth extraction as we age. It’s been around since the 1900’s and it was only during the 1960’s that a new material (composite) was produced which allowed us to create a restoration that looked like a tooth.

Dentures have been around since the time of the Pharaohs but really got going about 500 years ago. In 1988 they were no longer carved out of whalebone or wood but made out of plastic instead, that change being made during the 1960s, the age of plastics.

Dentures do have the advantage of being quick and easy to make, as well as being cheap, but their biggest problem is that looseness is an inevitable part of wearing them and some patients just never adapt to that, either leaving them in the drawer or, like my uncle, living in constant fear of embarrassment and sometimes even shame.

To try and prevent that looseness the denture clasps around other teeth in the mouth but in doing so traps plaque and bacteria between the tooth and the denture, encouraging gum disease and decay. Not a great outcome.

Bridges and crowns were some of the more advanced dental techniques available in 1988. Crowns are armour plating for a tooth and were used primarily to hold a tooth together that would otherwise have fallen apart. Bridges are a permanent alternative to a denture for replacing a missing tooth so long as there are only a few teeth missing, but the process of preparation in both cases incurs a high biological cost. (Biological cost is when part of a tooth is sacrificed in order to save the whole tooth. During preparation for a crown or a bridge 60% to 70% of the natural tooth is removed, with the consequence that after crown placement the tooth could develop an abscess and require root canal treatment) All of these problems were recognised at the time but we just didn’t have anything better. A gold crown was recognised as being the gold standard of restoration but a gold tooth doesn’t look too much like a real tooth and the nerve could still die off underneath.

With both dentures and bridges a domino effect exists where the provision of a denture or bridge to replace one tooth is more likely to result in the loss of more teeth.

All in all, when a patient in 1988 opened their mouth widely enough to see their back teeth you expected to see teeth black with amalgam, if they weren’t then you knew they had dentures.

For a dentist who really wanted to save a patient's teeth the options were fairly limited. To change this what was required was not just some fiddling around the edges but a completely different approach. On the day I graduated in 1988 (a quarter-century ago) the seeds of two such approaches had just recently been planted.

The first porcelain filling was placed in a tooth, in the University of Zurich.

The first osseo-integrated implant was placed in a patient’s jaw.

Both of these have revolutionised the outcomes for dental patients today.

How?

 

Part 3

Porcelain fillings are able to replace most crowns

Implants, not dentures or bridges, are now the best replacement for extracted teeth.

Porcelain fillings keep the tooth healthier than a crown or composite/amalgam, they are easier to place than crowns and they look better.

Porcelain fillings have a tiny biological cost in comparison to crowns and this means that the nerve underneath the porcelain filling is much more likely to not require root canal treatment six months later. The incidence of root fillings after crown placement is between 5 and 10%. Under porcelain fillings generally only those cavities which are already into the pulp end up needing root canal treatment. Aesthetically, the translucency of the porcelain matches natural tooth enamel very closely with the effect that the porcelain filling blends seamlessly with the tooth. A crown requires three weeks between preparation and fitting, a porcelain filling can be completed in one day. It ticks all the boxes of useful technology and to cap it all, in our practice at least, they are cheaper than crowns.

 

Why can I say that implants are now the best replacement for a natural tooth?

They are fixed permanently into the mouth, so no fear of the denture moving during speech, chewing function is completely restored after being completely lost and they keep the rest of the teeth in the mouth healthier, no domino effect. Dentures obtain their retention from the other teeth in the mouth. Implants by contrast, are fixed permanently into the gum, they touch only the teeth on either side, so they don’t induce gum disease and decay in other teeth and they are as firm in your gum as a natural tooth.  Because they don’t move the implant takes its fair share of loading and so the remaining teeth don’t have to bear any more strain than they were naturally designed to take.

Bridges are also fixed permanently but are destructive on the teeth that are prepared (like crowns), which sometimes results in abscess formation and they are harder to clean and floss around than natural teeth. An implant is as easy to clean around as a natural tooth.

But, good and all as these treatments are compared to what went before, there will inevitably be something better somewhere in the future.           

What lies in the future for dental technology?

 

Part 4

Smart people are currently working on two developments which hold a lot of hope for the future.

The first is growing teeth within the gum from adult cells which have been stimulated into forming stem cells, which can then grow into a tooth. This sounds initially very enticing but it does have a few problems in that it takes 5 years to grow a tooth from scratch. Nobody will want to have that gap at the front for 5 years until a new tooth comes through, and there is no guarantee that it will look the same as the existing tooth beside it.

Another technology which probably holds out more promise not only for dentistry but for the world in general is that of 3D printing. Already a Belgian dentist has been able to print a jaw made from titanium and implant it into a patient. This has obvious benefits for both dentistry and medicine in general. Already we have titanium implants to replace the root of a tooth, but these are one-size-fits-all items where the jaw has to be made to fit the implant, the ideal is something that can be custom fit to every person. More exciting than titanium teeth is tissue printing. This technology realistically holds the hope of being able to print a tooth then implant that tooth into a person’s jaw. Like titanium implants, but made of enamel and dentine, we overcome the problem of the 5 years it takes to grow a tooth naturally. This is really exciting and mind-boggling stuff.

If this is so good then why haven’t we heard about it already? The answer is that it is still in very early stages. Researchers have already been able to take the first step of being able to print tissue using a patient’s own cells and currently they use this scrap of tissue to test the effectiveness of anti-cancer drugs. Immersed in a nutrient liquid the cells are only the size of a cube a few cells wide by a few cells high so pretty far off being a tooth. The factor preventing the creation of larger structures has been an inability to create blood vessels to supply nutrients, but even this step is being solved by clever people bending their minds to doing amazing things. Nina Tandon gave a talk at TED June 2012 where she explained how exactly they were now able to do that. It seems to be only a matter of time before an entire tooth can be printed from a patient’s own cells, ensuring no rejection by host, then implanted. No doubt there will be a bagful of issues to overcome before we get there but the principle seems to be already established, it’s simply a matter of expanding an existing process.

Technology has revolutionised what we can achieve for patients over the last 25 years. When it comes to the human body nothing will ever make us bulletproof but there are new ways of helping us work toward that which have been developed and newer ways which are being worked on again. Growing your own tooth and putting it back into your jaw sounds like something out of Star Trek but we are closer to that point than anybody could imagine. Within my practicing life I am looking forward to being able to do exactly that.

As many of my patients tell me, dentistry has changed out of all recognition since they were young.

The best, however, is yet to come.

 

 

 Dr. Ian Harper

 

FAQs

Why do you take an hour for the first exam, when other dentists don’t? Why do I need to see a hygienist? Can’t the dentist just clean my teeth? Will they cost more? I haven’t been to a dentist in years & I’m worried about what they might find. What’s the difference between a porcelain filling
and a cheaper one?
How do our dentists look
aftertheir own teeth?
Why do I need X-rays?
Do they do me any harm?
If it isn’t currently broken,
do I need to get it fixed?