by Richard Mounce, DDS
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Creating positive endodontic resultS is a compilation of many small steps, each done well. Each step acts as a platform for the next stage of the procedure. An arbitrary set of these steps that can collectively help the general dentist optimize treatment is listed below. These include:
- Always reproduce the patient's chief complaint. If, for example, the patient has pain to cold or hot, test all the teeth in the quadrant, as well as the contralateral tooth with the same thermal stimulus, to determine the culprit. Never take a patient's word as to the offending tooth.
- Verify profound anesthesia before starting treatment. If the chief complaint is pain to cold, challenge the tooth with ice to assure the patient is asymptomatic before starting.
- Estimate the working length from the radiographs before access. This initial estimate should be very close to the true working length (TWL) determined later.
- Always use a rubber dam, and ideally use enhanced visualization and magnification such as the surgical operating microscope (SOM, Global Surgical, St. Louis, Mo.).
- Before starting, assess the external root form of the tooth to give the best three-dimensional mental image of the position of the chamber.
- Create straight-line access; assure yourself all canals are located before entering any. If you do not find the canals where expected, immediately take a radiograph. If in doubt, refer.
- Estimate the expected master apical diameter and taper before a canal is entered. This determination is made from a careful evaluation of three radiographs from various angles (mesial, distal, buccal). The more complex the root form, the smaller the master apical diameter and taper. The converse is true.
- Always remove the cervical dentinal triangle (CDT) by removing dentin against the root wall with the greatest amount of dentin up and away from the furcation with a rotary nickel titanium (RNT) file system such as the Twisted File (TF)*. There is no need for Gates Glidden drills or special orifice openers. Aside from CDT removal, TF allows the entire root canal to be shaped in approximately two thirds of the cases treated with one or two TF instruments. In addition, TF technology will safely prepare most canals to at least an .08 taper.
- Stay patent at every stage in the treatment. Irrigate and recapitulate after every RNT instrument inserted into the root canal system. Irrigant syringes can be drawn up in advance. Irrigation is more effective when it is heated and activated (ultrasonically or otherwise).
- Always have a canal that is open to the size of a No. 15 hand K file before inserting an RNT file. Some canals will have this diameter available naturally, and in other canals, this minimum diameter will need to be created. The use of a reciprocating handpiece such as an M4* safety handpiece can be very helpful in making this initial enlargement to a No. 15 hand K file.
- Precurve all hand files. All canals are curved somewhere along their length, even if they appear to be radiographically straight. As a result, they should be explored with a curved stainless steel hand file. Have copious quantities of Nos. 6, 8, and 10 hand K files arranged on the sponge for easy access.
- Once a hand file is able to reach the estimated working length, the true working length should be determined electronically. After the first and last RNT are used, the TWL should be verified again.
- Tugback should always be obtained if using a master cone-based technique for obturation. The master cone should slide passively into place with contact only in the apical 3 to 4 mm, both with and without sealer.
- The coronal restoration is ideally placed after obturation with the rubber dam in place. If a specialist treats the tooth, instructions for the desired coronal seal should be clear to eliminate miscommunications and subsequent coronal microleakage.
- Take the tooth out of occlusion if possible after placement of a coronal seal.
A clinically relevant series of steps has been presented to provide solutions to common clinical problems. Emphasis has been placed on patency, copious irrigation recapitulation, and early coronal seal with the rubber dam in place at all times.
I welcome your questions and feedback.
* SybronEndo, Orange, Calif.
Dr. Mounce offers intensive, customized, endodontic single-day training programs in his office for groups of one to two doctors. For information, contact Dennis at (360) 891-9111 or write RichardMounce@MounceEndo.com. Dr. Mounce lectures globally and is widely published. He is in private practice in endodontics in Vancouver, Wash.