August 6, 2020
Oral health during Covid-19 lockdown.
Welcome to issue sixteen of YOUR DENTAL CARE News.
In our fifteenth issue we discussed about testing and treatment for OSA…. If you missed this issue please visit our website http://www.procarefamilydental.com.au/news.
In this issue we will discuss Root canal treatment.
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Why the bad press about Root canal treatment?……..
What is root canal treatment?
Each tooth has a space in the middle of the crown and in the root. This space houses the pulp containing nerves and blood vessels. This pulp tissue keeps the tooth alive by responding to its environment.
The pulp makes more tooth structure when the tooth is stressed. This protects the pulp from bacteria and also helps bolster the strength of the tooth when it is overloaded during periods of teeth grinding.
Bacteria invading the tooth through dental decay or a crack will cause inflammation and pain from the pulp. This alerts you to a problem. But when the symptoms of discomfort are ignored the bacteria continue their advance into the tooth. Eventually the pulp begins to die and the toothache won’t go away but increase in intensity.
In order to keep the tooth the dead pulp or inflamed pulp must be removed along with the bacteria. Once the space inside the tooth is disinfected the space is filled and the cavity restored. This process of treatment is known as root canal treatment.
The only other alternative to root canal treatment is extraction of the tooth and replacement with a prosthesis. Root canal treatment is a good option to save a diseased tooth from being lost.
Figure 1. Diagram showing the anatomy of a molar. One half is healthy and the other shows the presence of an abcess. Courtesy of Dr Noel Garza.
Does a tooth need to be crowned after root canal treatment?
Most teeth which are root canal treated either have lost significant amounts of tooth structure to dental decay or are cracked. These teeth need a crown to support the remaining tooth structure from fracturing. But more importantly the crown, when done well, acts to seal the tooth from bacteria entering the tooth and reinfecting the canals within the tooth.
Not all teeth need a crown to seal the tooth and restore it. The dental literature has confirmed that molar teeth having had root canal treatment are best preserved over the long term with a crown. Due to the strong chewing forces at the back of the mouth these teeth benefit the most from a crown.
If crowns are not used on such fragile teeth the likelihood of tooth loss is very high. Furthermore root canal treatment can be reinfected from the bacteria in the mouth. Crowns offer the best method of sealing the tooth.
Figure 2. This is a zirconia crown on a stone model.
Why does root canal treatment take so long?
This form of dental treatment is very complicated and requires a high degree of skill. The openings into the spaces of the pulp chamber and canals are constricted and difficult to identify without visual magnification. Access to carry out treatment can also be challenging especially when dealing with molars.
But the greatest problem lies in the disinfecting process. The space inside the tooth is far from uniform in shape or size. In fact the canals and chambers are the main areas where the bulk of the pulp resides. However the spaces are really a labyrinth of complex structure which makes mechanical cleaning with special instruments difficult. The use of antiseptic products to flush the canals is carried out followed by the application of antibiotics. These are placed into the disinfected spaces and left in the tooth for several weeks to months, depending on the case. The antibiotic is necessary to penetrate into the complex spaces which the cleaning instruments or antiseptic fluid cannot get to. This will hopefully disinfect the tooth further.
After several weeks the tooth is accessed again, disinfected and filled with antiseptic cement followed by a sealer. So the whole treatment process can take up to 3 visits. In a small number of cases a single visit is sufficient to complete the treatment.
Figure 3. This diagram shows a molar with an instrument in the tooth which is used to clean the root canals. Courtesy of Colgate.
Why the bad press for root canal treatment?
Root canal treatment receives a bad reputation because sometimes local anaesthetic doesn’t work. This happens when the pulp is very infected and significantly inflamed. The procedure is quite painful in such cases. However there are methods of dealing with such teeth to make the procedure less traumatising.
Failure of root canal treatment is caused by many factors. The most common is the resistance of the bacteria in the root system to antibiotics and disinfectants used during treatment. Also if the bacteria make their way out of the tooth to infect the surrounding bone an abcess results. This reduces the likelihood of success further. This is a good reason to see a dentist quickly when a toothache starts. The sooner the condition is managed the less infected a tooth becomes and the likelihood of an abcess arising is reduced.
Other factors like cracks in teeth can lead to bacteria entering the tooth again. Also the tooth can continue to fracture even with a crown on it especially in situations where there is an extensive crack in the tooth to begin with.
A tooth with a good root canal treatment restored appropriately will have the best chance of survival. The best form of root canal treatment is no treatment. The best way to avoid root canal treatment is to manage teeth problems quickly. Prevention is definitely better than the cure!
In our next article we will discuss teeth grinding or bruxism.
Keep smiling and thank you for reading.
Dr Roland Chong