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Using New Technology to save an Old Crown

July 18, 2018

For my 50th Birthday I avoided the trappings of a late mid-life crisis and decided to treat myself by refurbishing the surgery and ended up with one of the most technologically advanced surgeries in Ireland. More useful than a fancy car. 

One of the items I decided to invest in, was a dental laser called a Waterlase.  This has now become an essential part of my equipment used every day. It has quickly become indispensable.




In this case a patient attended with a complaint of recurrent episodes of pain from a crowned tooth in the lower left. It was an old crown. Both the radiograph and exam showed an area of extensive decay that was easily probed in the mouth. The patient had previously had two courses of antibiotics to relieve pain but this was the worst episode. 

The patient wanted my opinion if the tooth could be saved.  The patient was also concerned about the possible cost of a new crown onto of the cost of root filling the tooth. 

I explained to the patient that this was a case of bacteria management. Bacteria had leaked under the surface of the crown and lead to the extensive decay, reaching the nerve of the tooth, now dead.  To save the tooth I needed to remove all the bacteria, seal the tooth from further bacterial invasion and then clean and sterilise the canal removing the dead nerve tissue.


Starting the Treatment

My first point of business was to access the dead nerve and so once frozen we cut a hole through the crown to allow me to access the nerve.   As soon as I had established the nerve canal I then removed all the decay from around the crown. Decay is a bacterial infection of the tooth, if I am to get the tooth sterile I need to remove the source of the bacteria namely the decay. In this case we removed decay from the inside. As I stated earlier I could probe the decay from the outside of the tooth and so  I used the laser to expose and remove the decay around the margin of the tooth.

Once I was sure I had the tooth decay free, I blocked off the canal with a gutta percha point and injected Glass Ionomer filling, to both seal and fill the tooth.  Once set I pulled out the point to re-establish access to the canal.


The picture opposite, shows the tooth just after the band was removed and the extent of the decay around the crown. The filling was polished down, the area cleaned thoroughly.

Also visible in this photograph is a sinus where this long standing infection had started to drain through the bone.

I then took a radiograph of the tooth (see below) to allow me to assess and check the filling. I was happy with the appearance of the filling.  Now that I felt the tooth was adequately sealed and decay removed I could start to carry out the root filling.

I explained to the patient my role in successfully root filling this tooth was to remove all the dead nerve tissue from the canal and then sterilise the canal as fully as possible.

The canal is a dead space to the bodies immune system, it cannot reach the inside of the tooth. I need to take care of all bacteria inside the tooth, and then the bodies immune system will take care of any infection outside the tooth.

 Mixing Old and New Dentistry

Our treatment of the root canal is now a mixture of the old and new. I will access the canal and prepare it using the traditional files and Sodium Hypochlorite (NaClO, medical grade bleach) according to the traditional best evidence treatment, but I augment this with the laser.

For the second time in the treatment of this tooth I reach for the laser and use it to clean and disinfect the tooth. 

All my work is carried out using my operating microscope, as I wash out the with NaClO I can see the waste product wash out and eventually the liquid remains clear. 

However as I proceed with the laser I get further debris, washing out of the canal. As I pass the laser tip along the canal, the energy of the laser causes micro explosions and implosions of the water in the canal.  This effect scrubs the canal clean, removing further hard to reach debris. 

Finally I switch the laser to disinfection mode.  Now the light emitted from the tip at 360o will destroy any remaining bacteria. At this point I am ready to complete the treatment and cement in the root filling.

Completing the treatment and cementing in the root filling.

Pictured opposite is the tooth after 3 weeks, the tooth has settled down and is completely comfortable to eat on, and is functioning well in the mouth.

For me the most impressive fact is the degree to which the bone is healing around the tooth. At the time of treatment there is a clear area of bone loss around the end of the root. In dentistry we allow 1 year to allow the bone to fill in and anything up to 5 years before considering the treatment a failure.

I am very pleased to see the area is greatly healed within the 3 weeks, especially as this patient is approaching their 72nd birthday, when we would expect healing to be slightly slower.

As the crown is now functioning well, I will keep the tooth under review. I see no reason at the moment to replace the crown and needless to say the patient was delighted at the reduced treatment. I am a firm believer in re-use and recycle where possible.

I started this article, stating it was new technology for an old tooth. This has been the tale of the entire treatment.

The filling material, Glass Ionomer, was the very first white adhesive filling material available to dentists. It is a great material, the only filling that chemically bonds to the tooth.

It is naturally rich in minerals which it releases into the tooth to protect it. Every time this patient uses a fluoride tooth paste the Glass Ionomer will regard itself for lasting material . The root filling is a Gutta Percha point with Zinc oxide/Eugenol cement.  Again it has been used for over 100 years.

Both these materials are well established with solid research and clinical guidance behind them They are constantly improved but the basic formula remains. There are lots of newer materials available but I don’t believe in re-inventing the wheel, both these materials are fit for purpose.

However the new technology offered by the Biolase is a different matter. In my view it is a total game changer. Treating one tooth I can use it to remove decay, treat the tooth surface for better bonding, reshape the gum or bone around the tooth, treat gum disease, or clean a root canal. Same hand-piece, quite often the same tip, it just requires me to adjust the power settings.

I don’t believe in the latest newest gadget or materials, just for the sake of change, but the treatment possibilities and improved outcomes for my patients that the laser delivers more than justified the price.

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