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Essay on a complex composite restoration using laser

422583987560The patient attended with a complaint of extreme temperature sensitivity from the Upper Left Side that was starting to present symptoms without stimulus. This is a sign the nerve was inflammed,and progressing to irreversible pulpitis, where the nerve becomes necrotic and requires endodontic treatment. The case was discussed with the patient as it was urgent to remove the restoration and any decay.  The patient was informed that due to the symptoms and depth of decay, the tooth may require further treatment (root filling). Anaesthetic was given and a rubber dam placed to provide protection and comfort to the patient, and allow me to treat the tooth aseptically and isolate the tooth for optimum bonding.

422583987740The amalgam restoration in the Upper Left First Molar (UL.6) was removed to reveal extensive decay. All my work is carried out using my operating microscope, in removing this amalgam I section the block of filling into three pieces, which are then lifted out; this reduces mercury released from the filling. The magnification of the microscope allows me to remove the filling without cutting the tooth. At all times I try to conserve healthy tooth tissue.

All decay is removed from the cavity, I use a combination of special drills that will remove only the softened decayed tooth, leaving healthy tissue. As the decay was  close to the nerve, I used the Waterlase i-lase to work in the most delicate areas. The laser works at a cellular level, it selectively removes the darker, stained decayed tissue.

422584195030As a traditional drill cuts it significantly raises the temperature of the tooth, it also tends to rip the surface opening cracks deeper into the tooth. When I am so close to the nerve these factors could lead to fatal damage to the already delicate nerve. In contrast, the Waterlase is a cold cut laser that has minimal temperature increase, it doesn’t cause fractures within the surface, in-fact it leaves the surface sterile.

 

422583988040It was clear that the filling behind was also  defective with an uneven face, the patient agreed that I should replace the front part of the filling at the same time to allow me create the optimal shape to allow these teeth meet effectively. Again I carefully removed the restoration, with minimal contact or removal of tooth. All these stages are photographed using the on-chair camera, to allow me to show the patient where and why decay has occurred. In this case it helped reinforce why flossing is so important.

As before using traditional drills and laser I removed all decay to prepare the teeth for bonded restorations

422584195030At this stage I use our Aqua-abrasion unit to lightly clean all surfaces with a highly mineralised powder Sylc, this removes and contamination, smooths the surfaces removing any irregular shards and creates a highly mineralised surface layer.

I then set the laser to a low level called bond prep, all dentine surfaces are treated at this stage, the laser sterilises the dentine roughens it slightly leaving it in perfect condition for bonding.

Finally, in this case as the nerve of these teeth were inflammed I applied Low Level Light Therapy to the teeth using our diode laser. Low energy is absorbed by the nerve tissues starting photo-chemical changes in the nerve that is as effective as steroids in  reducing inflammation and increasing the chance of the tooth survival.

422584195180The enamel is etched with a weak acid to aid bonding, normally I would etch the dentine, however as this has been treated with the laser it is not necessary.  The tooth is washed and then dried with absorbent paper points, drying with blasts of air is too harsh and damages the dentine surface of the tooth reducing bond strength. Once dried the surface must remain dry for bonding this is where the dam is vital.  It is easy to stop a cavity being contaminated with saliva, but only a rubber dam stops contamination by the moisture within your breath.  Any contamination will weaken the strength of the completed filling.

 

422584195670The bonding is the first line of defence for a tooth, the dentine is best thought of as millions of minute tubes running down into the nerve of the tooth. The bonding liquid is like a varnish, it is sucked down into these tubules, sealing the nerve from bacteria and providing the physical grip for the restoration.

The second line of defence are the walls that replace the missing walls, over 90% of fillings involve the walls where teeth

contact, these are the hardest to clean (flossing) and so are most prone to decay. I build this up like a curtain across the tooth in sections. This allows me to inspect the join of the composite to the tooth, to ensure they are sound and seal the tooth. As composite sets in contract  slightly by building the wall in increments we can minimise the effect of this shrinkage.

422584196050Once I have completed the outer walls I restore the inner bulk of the tooth with a material called Glass Ionomer, it is rich in minerals, that are released into the tooth to help re-harden the tooth and protect against further decay. Due to the mineral content, it is naturally antibacterial, further protecting against decay and as it sets it is dimensionally stable. The only downside is that it has a poor wear rate and so as it sets I impregnate the surface with a layer of bonding that acts as another layer of sealant and allows me to bond a protective roof of hard wearing composite  to the Glass Ionomer.

422584366210Finally the restoration is completed as I bond the composite onto the glass ionomer, again to manage the low percentage shrinkage of the composite it is added in sections to the tooth wall, this allows the shrinkage to occur at the free end of the composite and protect the join of the composite to the tooth wall. This tooth wall bond is important as it is the site of any future decay.

Eventually all that is left is to bond in the final central island of composite to complete the restoration, I then cover the entire surface with a final wash of sealant that is cured and set.

 

422584366570The tooth had been very painful, it had totally settled within 2 days and remains trouble free.

This restoration was very deep, I was close enough to the nerve to see it’s colour below the dentine, I am convinced being able to use the lasers to remove the decay and help resolve the inflammatory state was vital in the successful outcome.

This patient was new to the practice, I have discussed the cause of the decay and started our preventative programme to improve the conditions to allow this restoration remain healthy.

Composite is a great restoration material, superior to the old standard silver amalgam fillings, but it is very technique sensitive. I have not used amalgam in over 15 years and have composite fillings that have lasted over 20 years. The materials I now have available are vastly superior to the materials then. My technical ability has greatly improved through investment in both education and equipment.

I am heavily involved in sport and have a great interest in how excellence is achieved across the differing sports, the successful ones all look at every aspect of performance and try to make a small improvement at every level, time and again these many small improvement lead to world class excellence, these are the lessons from the British Cycling, Mercedes motorsports and more.

I try to apply the same ideas to my dental work and in particular the use of composites. I started to use isolation and rubber dams in 2006, I had been to two courses with world leading dentists, both were using dams and considered them necessary; the message from Prof. R. Elderton at the second course was blunt, “if you are placing composites restorations and not using a rubber dam, stop using composite”  I bought a rubber dam kit at the trade show, came home and have been using them since. Rubber dam doesn’t provide a small change it is a game changer.

Since then, the small changes have been in my technique and improvements in the materials, but then the next big change has been in the use of the laser. The ability and accuracy of the laser in comparison to a conventional drill is massive. I joke that it is the same as a doctor performing surgery with a sharp spade, then being given a scalpel.

I am pleased with the above restoration, but I am always aware that as good as it is, it isn’t as good as the natural tooth that suffered decay in the first place. The filling faces two challenges in the mouth; the challenge of the physical forces that will be placed upon it, but potentially more damaging is the bacterial attack, Their need to be changes and improvements in the factors that have led to the original decay. Again some small changes in diet, brushing and flossing can add up to a great improvement in the chances of long term success to the restoration. This applies to every filling, crown veneer or implant placed.