Pretreatment – Is it worth the Effort?
Pretreatment involves preparing a tooth for Endodontic treatment. Many endodontically involved teeth are heavily broken down or carious. Some involve deep fractures, subgingival proximal caries or faulty margins. The need for proper isolation of a tooth during Nonsurgical Endodontic treatment demands the use of rubber dam. Adequate isolation and proper asepsis during treatment can only be achieved when the portion of the tooth to be clamped is in a reliable condition, the clamp is secure and the dam seals the tooth be be treated. Failure to adequately pretreat a tooth can result in contamination of the working area through rubber dam leakage, clamp disengagement or loss of reference points. Pretreatment does require extra effort on the part of the dentist and slight added expense to the patient. However, this is more than made up in the ease of treatment and asepsis of the working area both during and after treatment. It also gives reasonable assurance that the tooth will be protected until it is restored.
Types of Pretreatment
- Removal of all caries and defective restorations
In order to consider any tooth for endodontic treatment, we first must determine if it is restorable. There is nothing more embarrassing for clinician than to complete endodontics through a crown, only to find that the remaining tooth is not restorable and must be extracted. This can be prevented by removing all caries and defective restorations from the tooth and examining for adequate remaining tooth structure. If you are satisfied that the tooth can be restored, move to step 2.
- Gingivoplasty/Gingivectomy with scalpels, Electrosurgery or Lasers
In some cases, caries, fractures or defective restorations are subgingival. Teeth with caries is just below the gingival crest can occasionally be treated by judicious use of a scalpel, electrosurgery or gingivoplasty where hyperplastic or excessive gingival tissue is removed to allow placement of a rubber dam clamp. In severe cases, such as those with muco-gingival involvement, those that require osseous recontouring or apical repositioning, referral to a Periodontist may be necessary before initiating endodontic treatment. There is no point in treating the case endodontically if attainment of proper biologic width, a healthy periodontal condition and proper patient hygiene is not achievable.
3. Reinforcement of the remaining tooth structure
Sometimes a tooth will be so broken down that insufficient solid tooth remains to use a rubber dam clamp. On other occasions the clamp may be able to be placed, but the post operative fragility of the remaining tooth poses a serious risk of vertical or cusp fracture. (Loss of a reference cusp during treatment can mean inaccurate working lengths.) In those cases, reinforcement of the tooth is necessary.
For many years banding of teeth with copper or orthodontic bands was the method choice. With the development of deeper curing light cured composites and fast setting bonded core pastes, banding of teeth has become less common. However, the copper band offers one advantage that these other technologies do not… the ability for the rubber dam clamp to securely engage the soft copper of the band and not come loose. As much as I dislike taking the time and trouble to place a copper band on a tooth (a well fitting band in a tooth with previously deep proximal restorations can take 20 min. or more to place), I invariably love the results. The case is much easier to treat, isolation is easily achieved and the rubber dam remains secure throughout the treatment. The tooth also has much less chance of post-operative loss of seal or fracture. The properly contoured copper band can also serve as an excellent temporary restoration in cases where patients cannot afford to have the tooth restored immediately, or where other, more important treatment dictates that the tooth remain unrestored for a few months.
Copper Band Placement Steps:
- Band size selection is VERY important – Select a band that fits snugly around the tooth but not so snugly that it cannot be removed. It should also not be so large that it has big overhangs. Anneal the band to soften the copper, if necessary. (Heat to red hot in open flame and quench in alcohol in a dappen dish). This renders the copper dead soft.
- Place the band over the tooth and score the inside and outside of the band with an explorer to indicate the height of the occlusal surface. Cut the band with scissors to and check for fit. Notch one side of the occlusal surface of the band to allow the copper to be pushed down and contoured to fit the occlusal areas. The band should draw off the tooth and be able to be placed in the tooth easily. In some rare cases, the proximal surface(s) may need to be reduced to allow it to be seated.
- Polish band with Joe Dandy disc and rubber wheels to smooth the outside surface of the band. Dry and isolate the tooth with Dri-angles and cotton rolls
- Mix ZnPO4 Crown and Bridge cement. Two types of consistencies of mix are necessary:
(1) typical C&B loose cement – used to cement the band. Place cement on inside of band and seat by hand. Contour the Cu band as necessary with a band pusher.
(2) A second mix is made by immediately adding more ZnPO4 powder to the first mix to create a “doughy” ball of cement. Be careful with this mix, as too much powder can cause immediate set. Place powder on fingers to prevent the cement from sticking to your gloves and push the ball of cement on to the occlusal surface of the tooth, ensuring adaptation to any proximal surfaces. Some excess may be visible around the band edges but proper contour and fit will ensure that it is not excessive. Use band pusher to contour the apical and coronal portions of the copper band to adapt to the tooth as well as possible. Once cement becomes doughy, stop all manipulation and wait for the cement to harden.
- Once the cement is set rock hard, flick out any proximal excess with a plastic instrument or scaler. Trim band and cement from band margins to create smooth occlusal surface and check occlusion. Perform final polish of trimmed band areas with green rubber wheel or points. Tell patients that while this may feel as hard as permanent restoration, the copper still can be deformed or cement seal broken if it is abused. Tell them to treat it “like a temporary filling”.
Your rubber dam clamp will now easily bite into the soft copper and the rubber dam with be securely placed. When removing the clamp be sure to open the forceps and disengage the entire band completely before removing the dam. Failure to do this when minimal tooth structure is left can dislodge the band and require you to replace it again!