When to Obturate the Canal

Regardless of the material and the technique used, certain parameters should be met before the canal is considered ready for filling.

There are various schools of thoughts illustrating these parameters. These thoughts come from the clinical experiences of various practitioners and research of scientists. We always believe that endodontics moves with the clinical symptoms and signs. Listen to the tooth and it tells you what to do. To listen to tooth you need to know its language. It speaks in various languages. These languages when interpreted by your knowledge and your experience becomes the parameter. The important parameters are:

1) The Tooth is Asymptomatic. (The tooth is tamed)

This happens to be the first and the most logical and simple requirement for obturation. The tooth is lightly tapped with the butt end of a mouth mirror and by digital manipulation of the buccal and lingual plates of the bone surrounding the tooth. There should be no sensitivity or pain/tenderness during percussion or palpation. The presence of sensitivity indicates inflammation in the periodontal membrane space. If the canal is filled before the inflammation has subsided, the additive inflammation of filling, packing the canal, will cause extremely painful episode. Unless tissue resistance is strong enough to overcome this considerable increase of inflammatory potential, an area of periapical inflammation will result or a previously existing lesion will recur.

2) The Canal is Dry (The tooth is not crying)

It is important to check with the paper points that the canal to be obturated is free of all the exudates and is dry. This is done for two reasons.

a) Exudates from the canal is indicative of some infection. You will many times come across cases of weeping canals. Calcium hydroxide preparation helps to dry the canal.

b) Canal needs to be dry at the time of obturation for the adaptation of the filling material to the canal walls.

3) Presence of Sinus

It is controversial as to whether to do obturation in the presence of sinus or not. First find out the amount of bone loss and stability of tooth. Prepare the canal and ask for a follow-up after 2-3 days. If you find that the sinus shows signs of healing, canals are dry and tooth asyptomatic— you may obturate without waiting for the sinus to heal completely. Follow-up the patient to check the progress.

The presence of sinus is not a contraindication for filling. You may rather consider it as advantageous, as post-operative pain rarely occurs when ever the canals are filled with periapical sinus present.

Extension root of the sinus seen. (Vitapex extruding out of sinus and the distal pocket)

4) Foul Odour (The Canal smell ill)

Many years ago in my days of graduation my teacher used to tell two methods.

1) I was told to smell the paper point, used as a root canal dressing, and check for any foul odour.

2) The paper point was then dipped in hydrogen peroxide to check for any effervescence.

The logic was that, if there was a foul odour then canal was infected. The effervescence was an indication of the exudates.

Researches later reported a poor correlation between canal odour and culture results. Positive cultures were found in canals free of odour. In addition, a foul odour has been associated with anaerobic growth, which is difficult to verify without routine culturing technique. You should not consider absence of canal odour alone as any indication for filling. It must be correlated with other clinical

findings.

5) Negative Culture Test

This has been a dominating criterion for many years. It has been statistically found that there will be an average of 11% more success in healing when teeth are filled with negative culture. The probability of post-filling discomfort is more when the root filling is done into infected canals.

6) Temporary Filling is Intact

A breach or a washed off temporary filling is an indication of seepage of saliva in the canal. This may be presumed as a case of infected canal. You should always fill the temporary filling as if, you are filling it permanently. I have seen that temporary filling is always done with a very heavy heart. It is always considered to be temporary but is intended to work as permanently. The temporary filling should hermetically seal to prevent leakage of the canals and be strong enough to withstand the masticatory forces.

7) When you have enough time to achieve quality seal.(hungry, hurry, haphazard) It is a fact that you cannot do a good obturation if you are hungry, in a hurry or haphazardly organized.