Laser Dentistry: The Techniques and Benefits of Dental Lasers

Laser Dentistry offers innovative solutions for various dental procedures. Dive into the history of dental lasers, their applications, and why dentists are adopting them.

Why do I need a diode laser?

A diode laser is an essential tool for precise and efficient applications in fields like medical, industrial, and cosmetic treatments. Its compact size, energy efficiency, and ability to deliver targeted wavelengths make it ideal for everything from hair removal to cutting materials, ensuring high-quality results with minimal downtime.

What's the history of dental lasers?

Before we get to diode lasers, let’s look at dental lasers in general. Technically, laser technology has been around since the 1960’s thanks, in no small part, to Theodore Maiman. He was the man behind the first laser, which used a ruby crystal at its core.

This all seemed a bit theoretical at the time. ‘So what’, said the man in the street. He clearly didn’t even know what a CD player was at that time. However, time goes by. 30 years later, lasers became a bit more real to those attendees who were at London’s Alexandra Palace. That edition of the Dental Showcase Exhibition featured a certain amount of razzamatazz. Particularly around the ADT exhibition stand where some strange floor standing units were positioned.

No one, in the UK, knew what Nd:YAG was. Nd being the chemical symbol for Neodymium. This is a silvery white rare earth metal, what does it have to do with lasers. Well, it’s a critical element doped into the crystal rod at the heart of this laser cavity. What looks like a glass rod, is in fact a crystal rod grown in a laboratory. The YAG part of the chemical symbol stands for Yttrium Aluminium Garnet. A crystal rod then, positioned perfectly between two mirrors and ‘pumped’ by a bright flash light. That gives us the light which pervades the crystal rod, which then oscillates between these 2 mirrors. Some of the light is lost, but the rest builds power in the Laser.

As you might already know, Laser, as a word, is an acronym. It stands for Light Amplification by Stimulated Emission of Radiation. Another critical element of the whole system is an efficient cooling system to avoid overheating the crystal rod – hence the size of the units. Given that it’s pumped by a flash light, it’s no surprise that the Nd:YAG laser gives us a pulsed laser beam.

Can we see the light emitted from this laser unit? No. It’s infrared. It's beyond the human visual spectrum. The human eye extends into the 700’s in nano meters, which is red in colour. Beyond red is infrared.

The Nd:YAG wavelength sits at 1064 nano meters (often shortened to nm). How was this exciting energy delivered to the tissue though? The answer is a glass fibre. Flexible, with a handpiece at the end which could control precisely where the energy was directed and delivered.

The American publicity, of the time, claimed that these 1064nm pulsed lasers could work on any tissue. Sadly, there were some drawbacks with this claim. Whilst this wavelength is deeply penetrating through human soft tissue, it struggles with cutting teeth without the application of a dark dye.

Shame, a £40,000 investment for those who were convinced by the hype. But what a fantastic marketing tool for those who did invest – guaranteed publicity - with patients queueing to come along.

As the claims were steadily discredited, the razzmatazz died down. It would be nearly another decade before lasers next appeared in Dentistry. By then teeth could be successfully etched or cut, veneers de-bonded and dentine beautifully excavated by the Erbium laser. Using Erbium instead of Neodymium in the crystal rod. Soft tissue could be efficiently cut and coagulated by CO2 lasers. However, these were still big, expensive units and only the early adopters were excited.

But if this was in dentistry, what sort of lasers were the medical folks using? Their CO2 lasers were much more powerful, but still very effective for soft tissue applications. However, they also had compact semi-conductor diode lasers for therapy and some surgical applications.

The medical profession used these diode lasers where a flexible fibre could access awkward areas. These fibres and handpiece arrangements are very similar in design to those used on the first Nd:YAG dental lasers, so quite familiar. When I say compact, that’s compared to the Nd:YAG, Er:YAG and CO2 lasers that they co-habited with.

Whilst the Nd:YAG and Er:YAG lasers will always have a pulsed output, CO2 lasers can be used in Continuous Wave (CW) or Super/Ultra-pulse. A typical 30W CO2 laser can have an Ultra-Pulse of up to 500W peak power.

This high power sounds a bit frightening – but the pulses themselves are very short (microseconds) in length with a gap between each pulse allowing for tissue cooling, before the next laser pulse arrives. This method of delivering energy eliminates carbonisation. One of the negatives of using infra-red lasers is having anything black in the target area. As you are aware a black car compared to a white car, in the sunshine, will heat up much faster. This is the same issue with carbonised tissue. If we continue to irradiate carbonised tissue with an infra-red laser, there can be a tremendous heat build up. On tissue, this can lead to necrosis – so it should be avoided at all costs.

To avoid this heat build up, simply stop the procedure, wipe the tissue to remove the carbonisation with damp gauze or a damp cotton wool roll (just damp with water – no alcohol please!) then continue. However, this tends to make the procedure a bit iterative, but still very effective.

The Laser Output

By design, all diode lasers have a CW output. That doesn’t mean that they can’t have a pulse mode, but that pulse mode would be more of a gated pulse than the true pulse of the CO2 laser in Ultra-pulse mode.

Setting a diode laser into pulse mode would tend to reduce the cutting efficiency, so it’s rarely used. That is, until you lift the frequency of the pulses to at least 20,000Hz or 20,000 pulses per second. At this level, cutting efficiency is increased and carbonisation avoided. Some of the more technologically advanced diode lasers have pulse frequencies up to 50,000Hz.

Laser Wavelengths

Now that we’ve got this compact laser, what can it do? Well, that depends on the wavelength as this determines the tissue interaction. How many wavelengths are there? Quite a lot.

Let’s take a look a few popular ones.

940, 970, 980nm

These wavelengths offer good cutting speed, good haemostasis and an affinity for water. The water affinity of this wavelength helps with cutting speed, but reduces the penetration of this wavelength when used for laser therapy. For surface lesions, it works fine.

808-810nm

These wavelengths offer slightly slower cutting speed, compared to the 940-980nm range. However, that’s balanced by excellent haemostasis and a reduced affinity for water. The lack of water affinity of this wavelength allows for water irrigation during surgical procedures without any noticeable loss of power. This irrigation can act both in a cooling capacity as well as eliminating any smell of burning tissue – a major plus for patients.  

Anyone who has used electro surgery will know that horrible smell of burning that just can’t be eliminated. Due to the reduced water affinity, the penetration depth of this wavelength, when used for laser therapy, is up to 54%¹ greater than the 940-980nm series of lasers. For surface lesions, it also works fine. The excellent haemostatic effect of the 808-810nm wavelength comes with the negative. The propensity to produce carbonisation.

The way to avoid this is to pulse the laser beam at 20,000Hz or higher, which will increase cutting speed whilst minimising carbonisation^2,3. Due to the absorption characteristics, this wavelength is also suitable for antimicrobial Photo Dynamic Therapy (aPDT). This is a technique where a solution of indocyanine green is introduced onto the target tissue and low levels of laser energy are able to activate this solution to be bactericidal to the point of being able to significantly reduce the viability of bacteria⁴. This can be particularly good in both periodontal and endodontic applications.

The wide applications and characteristics of this wavelength suggest that it might be the best choice of diode wavelength for oral soft tissues^5,6.

450nm

This wavelength is blue in colour and has a high level of absorption in both melanin and haemoglobin as well as collagen. However, as this is a visible wavelength laser, the protective glasses tend to be quite dark and the beam intensity bright. It’s a similar effect to welding and discerning accurate tip placement needs more practice with this wavelength than with the others.

This wavelength can also be used for aPDT but with curcumin rather than with indocyanine green.

Let’s Meet our New Laser Dentist

Now that I’ve got my laser – 810nm being the most ubiquitous for therapy as well as surgical applications, what am I going to use it for?

Well let’s put ourselves in the shoes of a new laser dentist and take a look as some of the things that they might use the laser for in the first few months of ownership.

Dental Laser Applications:

Treating sub-gingival decay

There I am, happily working away, nicely coming up to lunchtime and Mr Smith is my next patient. He’s a lovely chap who’s been with the practice since it was first opened as a squat. We have a little chat, everything’s good, I just need to do a check-up. Is that sub-gingival decay hiding there just below that angry looking gum tissue? Oh dear. There goes a chunk of my lunch break. Hang on, can’t my laser help? He’s quite sensitive, so a little anaesthetic. I need a nice low setting, there’s no rush. What’s the preset on the laser? That should be fine.

Gently remove the gum tissue, with no bleeding. Perfect access. Pick up my drill, excavate the caries. Clean everything up. Etch and bond. Fill. Cure. Tidy it all up. Thank you Mr Smith – see you next time. Thank goodness for my laser.

Troughing around a crown prep

Though I say it myself, that’s a neat crown prep. Now to take an impression and George, at the lab, can get to work. I’ve got this lovely new digital scanner, but I’m not completely comfortable with this digital dentistry, so I’ll do an alginate as well. Before I do, I need to sort out that margin and there’s a bit of bleeding in the sulcus. Where’s my retraction cord? Hang on, can’t I use my laser?

Now what’s the preset on the laser? A nice low setting, I don’t want to remove any tissue – or it would be a big job for George. Just open that sulcus nicely – and stop that bleeding. Moving the laser tip around the tooth, quite quickly. Stop. That’s perfect. Hang on. It’s still bleeding. Right. Please the laser tip on the point of bleeding and count to 2. Give it a wash with the 3-in-1.

Great job. Wow, that’s faster and neater than retraction cord⁷. Now, first with the alginate and now with the scanner. That’s it, I can be confident that that crown will look just as good as the teeth next to it when Mrs Jones gives her winning smile. Good job.

Treating an aphthous ulcer

Good morning Mr Blake, how’s things? Great to hear. A what? An ulcer. Painful? Mmm. Hang on, we can treat that with our laser – give me a moment. That’s it an intra-oral tip (which looks very much like it should be on a curing light). Holding it just above the ulcer and painting the energy evenly around the lesion. Let me know when you can feel something.

What do I mean by ‘something’? Well, a kind of tingling in the area of the ulcer. Not a definite feeling like something has touched it – but a gentle ‘something’. It might take us a minute of two. Just raise your hand when you feel something. Thanks for raising your hand. Great.

So, you felt something? Please run your tongue over the ulcer now. What do you feel? So, much better, but still a bit painful on the edges. OK. Let’s do a bit more laser on it. Again, raise your hand when you can feel something. Let’s do it again. Great. So, you felt something again. Now, run your tongue over the lesion and let me know what you can feel. Nothing? That’s great. You should be pain free from that ulcer from now on, but if you do feel anything – just come back and we’ll treat it again. I’m so glad that we could help.

Non-vital tooth bleaching

What’s in the book today? Ah yes, Mr Singh for his crown to be fitted. I seem to remember that he had a discoloured non-vital tooth sat next to what will be a lovely looking crown. I was contemplating doing some internal bleaching on that, but I think that there’s a way to use the laser?

That’s right prepare it as if for ‘walking bleach’ but activate with the laser tip in the gel for around 10 minutes in the chair. Review and then change the gel and apply the laser again, if required. Let’s see how we get on.

What do you think of your new smile, Mr Singh? You’re very happy. That’s good to hear.

Soft tissue crown lengthening

Today we’ve got Sarah coming in. She wants a new smile before her wedding and most importantly her wedding photographs. We can do extremely thin veneers for her as her teeth are a lovely colour to begin with, it’s just the shape that we need to alter. Now, about the soft tissue. There are slightly different levels on one of the centrals and on the other side with the lateral. I wonder if there’s enough biological width for us to just remove a little tissue without compromise? That would transform her smile from very nice to absolutely fantastic?

What I’ll do is give some anaesthetic and probe both areas and try to establish the biological width. Yes, it turns out that there is enough biological width. I’m going to use the laser on a nice low setting, giving plenty of control - as we only want to change the shape of the sulcus and balance up the soft tissues. Sarah will be able to maintain the resulting tissue position just using her toothbrush – I’ll give her some instructions when we fit those veneers.

Treating trismus

That was a surprise. When Mrs Critchley came in for her check-up appointment. She had some difficulty opening her mouth fully and complained that her jaw had been sore for a few days, since she tripped and banged it. Now I was reading about the use of the diode laser for treating trismus just the other day8. Using the laser, with the extra-oral therapy tip in place, we can scan the 810nm laser beam in an area around the TMJ on both sides. We can do this with the jaw both open and closed. This will then relieve the pain that Mrs Critchley is feeling. It will also allow much improved the jaw movement. We only need very low power as it’s a therapeutic application, but the results reported were amazing. I can hardly believe that result – Mrs Critchley is delighted.

Frenectomy

I’ve always shied away from doing any surgery. There’s way too much blood and I don’t feel confident and in control. However, I was on a laser course recently and we were practicing the release of the lingual frenum on pig jaws. It was amazing to see how cleanly the laser was able to remove the tissue. Perfect vision, no carbonisation and such an easy procedure to perform.

I called Mr Booth and we had a chat about his tongue movements these days. He told me previously that he's always wanted to lick an ice cream. You know those lovely soft 99’s with their flake and almost a Teddy boy quiff of soft vanilla straight from the machine. However, the long lingual frenum under his tongue has always made that simply a wish rather than a reality. He and I had a conversation about removing that annoying frenum and releasing the ice cream lover in Mr Booth.

Using just a small amount of anaesthetic and with my nurse holding Mr Booth’s tongue in some gauze, we were all set to start.

Off we go with the diode laser tip just following that fine tissue of the frenum. Very straight forward. Absolutely no bleeding. No trauma. No carbonisation on the tissue. We used the laser at 7W. I was initially worried that this would be way too high a setting with too much power. On the laser course, we learnt about pulse mode on the diode laser. By using a 20,000Hz pulse setting, I had free movement of the laser tip which allowed me to move quite quickly and left the tissue with no carbonisation.

This is apparently to do with the ‘off’ time of the pulse allowing for tissue cooling before the next pulse of laser energy is delivered. The result was really good and Mr Booth went off to find an ice cream shop to start practicing his new found skills.

We had Mr Booth back for a review appointment 2 weeks later and he was full of it. Unfortunately, he can’t go past an ice cream shop now without partaking – so his wife has got him on a strict diet away from ice cream.

We also had another patient for a frenectomy. This one was down to a diastema that was separating the two centrals on an older male patient – a midline diastema.

This patient commented that he was finally getting fed of looking like Jimmy Tarbuck. When I examined the midline diastema closely, it became apparent that the centrals were separated by a superior labial frenum that came down from the upper lip. We had a chat about what I could do with the laser to remove this tissue and we got the orthodontist involved.

Once he agreed to proceed, we were able to remove the labial frenum – including the thick tissue between the centrals and get brackets onto the upper teeth to stabilise their alignment. He was blown away by his final smile – which even his wife fell in love with. Success.

Pulp Capping

I always get a bit nervous when there’s soft caries down close to the pulp chamber. It’s never on a day where there are convenient gaps and I’ve had a couple of situations where I’ve had to do endodontics as a result of an unfortunate pulp exposure. One of the discussions that I had on the recent laser course was to do with vital pulp therapy⁹.

This is where we can use the 810nm laser to stop the bleeding, get complete haemostasis and sterilisation on the exposure site and then carry on with a normal pulp capping procedure. Once completed we can then use the laser to reduce inflammation in the pulp therapeutically. So the direct application of the laser gives us the sterilisation and haemostasis using around 3W of laser energy – directly onto the exposure site. The clever bit is the therapy side where we can use a very small dose of laser energy to calm the pulp. Very clever and a great catch all – in case I make an accidental mistake. Very reassuring.

Exposure of an unerupted tooth

We have an orthodontist in the practice and she’s very much of the older school of thought. That means that she would tend to use a scalpel to expose an unerupted tooth with a view to bringing the patient back a week later to fit a bracket. I challenged her to use the laser. The next case with an unerupted tooth, we reviewed carefully together and decided how to approach it. We set the diode laser on 5W pulse (20,000Hz). Gave a decent amount of anaesthetic so patient and clinicians were relaxed. With the nurse adding drops of water to the tissue for cooling, we started. The orthodontist watched carefully as I gently removed some tissue to expose the enamel of the unerupted crown. She was amazed to see no interaction between the laser and the tooth. Meanwhile the soft tissue was being removed cleanly, with no carbonisation and no bleeding. I can’t believe that there’s no bleeding she said – after the patient had left.

Once I’d exposed the first third of the crown, I stopped and we swapped places. She’s had a decent play with the laser on some green apples, but this was her first live patient. Carefully, she mimicked my movements of the laser handpiece.

Slowly removing more tissue until she decided that a bracket could easily be fitted to the exposed crown and a chain attached to apply tension. No smell. No bleeding. No carbonisation. No trauma. No waiting for a follow-up appointment and the whole thing (with a swop over) took 15 minutes. She was amazed and will incorporate laser use into her standard treatment from now on. I’ll still help as required, but she knows what to do and how it all works.

Time and stress avoided

The two things that the laser brings to my practice is an amazing amout of time saved and stress avoided. It’s difficult to put a value on the latter, but with the former an unhurried cup of hot tea is almost priceless. Is the cost of the machine worthwhile? Absolutely. The old saying is that ‘You have to speculate to accumulate’ and I guess that’s true of this purchase. We’re getting a few referrals in just due to word of mouth from those patients treated by the laser, so there’s certainly something there. We’re not very whizz at the marketing side of things, but we were introduced to Chris Baker who is. Chris runs Corona out of South Wales and he helped tremendously with our presence on social media.

Laser Tips

There can be some negative perception about the cost of disposable laser tips and it's fair to say that some lasers do require relatively expensive tips in order to use the laser. You’re often encouraged to stock a wide range of them for different applications and that can all begin to add up.

Tips for the Dawn and Dawn Light lasers are more cost effective with purchases of 40 tips giving you 10 extra tips free. They work out at approximately £4.50 each (before the free ones) and last quite a while. They can also go through the autoclave between patients.

Laser Dentistry Training

How do I decide on a Dental Laser?

The thing is... Which laser should you buy?

Possibly start off with the Dawn Light laser, which is a 10W 810nm diode laser capable of pulsing the laser bean at up to 50,000Hz. Dental Sky are also offering this unit with 980nm although 810nm may well be the better option for the depth of penetration with laser therapy. This unit should see you through for a number of years as you build your laser expertise.

However, Dental Sky are also offering the Dawn laser (this is the Dawn light’s big sister) with 3 wavelengths available in the same unit: 450, 635 and 810nm (or 980nm). You may be excited by the blue light wavelength at 450nm.

With good in clinical training and hands on courses, Dental Sky are taking this quite seriously. Both the Dawn and the Dawn light come with 3 years warranty, so offer great peace of mind.

What do Laser Customers Say?

Dr Seb Lomas spoke enthusiastically about the quality of the in office training that came with his laser – on the back of attending a hands on course.

Dr Simon Agabeg enthusiastically commented: “Could I live without my diode laser?" 

Diode Lasers are part of my kit that I use multiple times a day. I have five Lasers in our two practices of which the Dawn light is the latest addition. The beauty of the Dawn light is that it uses a fibre which we just keep shortening. This means that each use costs a fraction of the disposable tips. It’s the same fibre system that we started with in 2007 when I got my first Velopex diode laser, so we’re well used to the way it works.

We use the Dawn light for troughing around fillings, inlays ,crowns and veneers. It’s especially relevant with our with Cerec system. I find it an essential tool for crown lengthening, frenectomies, operculectomies, implant exposure, cold sore therapy, and many other procedures.

So the answer is:  ‘no’, my laser is as essential as my loupes or handpiece and I can’t live without any of them.

References

1. D.E. Hudson, D.O. Hudson, J.M Winiger, B.D. Richardson: “Penetration of Laser light at 808 and 980nm in Bovine Tissue Samples”, Photomedicine and Laser Surgery, Vol 31. No 4 April 2013
2. R. Doshi: Technology in focus, Soft tissue crown lengthening, reducing carbonisation, PPD, pp129-130
3. N.H.K. Affendi, R. Ahmad, F. Vahidi, M.Z. Hassan, S.N. Rahimi, ‘The integration of a dual wavelength Super Pulsed Diode Laser for Consistent Tissue Ablation in the esthetic zone: a case series’, Case Rep Dent. 2020: 8883156
4. Sang Ho Shim, Si Young Lee, Jong-Bin lee, Beom-Seok Chang, Jae-Kwan Lee, Heung-Sik Um, ‘Antimicrobial photothermal therapy using diode laser with indocyanine green on streptococcus gordonii biofilm attached to zirconia surface’, Photodiagnosis Photodynamic Therapy 2022 Jun: 38: 102767 Epub 2022 Feb16
5. N. Akbulut, E.S. Kursun, M.K. Tumer, K. Kamburoglu, U. Gulsen, ‘Is 810nm diode laser the ebst choice in oral soft tissue therapy’, Eur J Dent, 2013 Apr-Jun; 7(2): 207-211
6. A. Gutierrez-Corrales, Y. Rizcala-Orlando, P. Moontero-Miralles, G. Volland, J.L. Gutierrez-Perez, D. Torres-Lagares, M.A. Serrera-Figallo, ‘Comparison of diode laser – Oral tissue interaction to different wavelengths. In vitro study of porcine periodontal pockets and oral mucosa’ Med Oral Patol Oral Cir Bucal. 2020 Mar; 25(2): e224-e232
7. D. Melilli et al. ‘Gingival displacement using diode laser or retraction cords: A comparative clinical study’, Am J Dent. 2018 Jun
8. E. Rasca, A. Namour, A. Fauchon-Giumeli, S. Nammour, ‘Laser phototherapy in acute post traumatic trismus case series study’ Laser Therapy, 2018 Sep 30; 27(3): 219-226
9. F. Afkhami, G. Rostami, C. Xu, L.J. Walsh and O. A Peters, ‘The application of lasers in vital pulp therapy: a review of histalogical effects, Lasers Med Sci. 2023; 38(1) 215