TOOTH FRACTURE TO THE OSSEOUS CREST
Because no ferrule is required, the direct MODXYZ may be the most periodontally- conservative long-term restoration if radical coronal fracture has taken place.
If the tooth is compromised in other ways that limit the desirability of crown work, this approach will be a very handy arrow to have in your restorative quiver… for example
- unchecked periodontal disease
- incipient furcation involvement
- limited budget
- terminal illness
METHOD OF RESTORATION
- If the break extends close to or all the way down to the osseous crest, we need to preserve biological width for long term periodontal stability. Sometimes it may be tempting to just place a restoration and see how it is accepted, but the process is seldom pleasing. If the break is a few days old, for example, the tissue will likely be collapsed over the stump. This makes it tough to find the margin, and to properly instrument the preparation.
- When the tissue is fibrous, sometimes you might be able to prep the root and manage the hemostasis conventionally , see Hemostatic Etch . However, more often than not the tissue is granulomatous or hyperemic, and you have a bull by the horns trying to achieve hemostasis.
- Another factor hindering immediate treatment is the likelihood that the fracture has left shattered tooth structure around the gingival line. If that unsound margin is restored, it will fail early due to micro leakage. The patient may also find the unsound margin exquisitely tender to brush, or whensubsequently touched by the dentist with an explorer.
- The break may also be inoperable in form – for example, a very fine, isolated spicule down the root.
- All these possibilities suggest the best strategy is to flap the site, perform crown lengthening, and make a definitive prep that has the ability to be properly matrixed and restored. You will then be sure of the integrity and access of the margin.
- Then temporize with IRM.
- The surgical process is very uncomplicated and goes like this: Raise a full thickness flap, (with, or without releasing incisions, as required.) Remove the bone with a new 1558 OS bur, copious water, light touch, vertically to 1.5 mm below the fracture,horizontally, to within 1/4 mm of the root surface.
- Clean the remaining bone away from the root with a Weidelstat or sharp curet/scaler.
- Prep the tooth as normal to receive a restoration, except retain any presenting GV Black retentive features to hold the IRM.Because the previous restoration is usually amalgam, there are usually remaining mechanical retentive features to help you out.
- Adapt a tempered .0015 band tightly to the prep, so that it will exclude bleeding. Shape with the Bandbender so as to prevent open contacts. Place wedges, leave the matrix filled with a wet cotton pledglet, and go away for five minutes. By then the bleeding should have stopped, and you can place the IRM.
- Wait until the IRM is fully set. Then reduce the bite to sub- occlusion. Being in sub-occlusion, the restoration will not be dislodged readily. Also, the tooth may super-erupt, which is all the better. If you use resorbable sutures to hold the papillae in place the patient will not need to come back. No surgical pack is required. Surgical pack is needed where you are trying to produce very specific interproximal control in periodontal resection, but this is a lingual or buccal fracture we are treating, not interproximal tissue.
- Wait 3 months and then book for the composite restoration.
The fee for this crown lengthening should be commensurate with the amount of time taken –seldom more than thirty minutes. The suggested fee for crown lengthening in my jurisdiction, which is British Columbia, is % over $500, and seems excessive for the limited procedure taken above. The fee for ”caries control requiring anesthesia and band” seems more suitable, and makes remuneration commensurate with the time,skill and responsibility level of this procedure.
- Pain? Post-operative discomfort has never been an issue with this approach. I believe the real source of pain in crown lengthening has been the widespread use of diamonds for osseous reduction, because they clog up quickly and produce local heat, which is anathema to happy bone. The healing around a smooth IRM surface is very good, and of course the pulp is happy from the ZOE.
- At the return visit in 3 months,,when modifying the prep for composite, eliminating stress risers, round internal line angles, see Enamel Axioms and Shoeing Cusps and Bevels and follow links from there.
- You may be concerned about eugenol interfering with the polymerization of the resin. Some research suggests that eugenol, as a bonding barrier, dissipates in three weeks, but clinically this is an invisible and unknowable factor.It seems prudent, rather than be uncertain, to freshly prepare bonding surfaces with burs and or sandblasting.
- When it comes to removing the IRM margin that is still sub-gingival,avoid a rotary bur under the tissue line. Attempt to preserve the epithelium of the gingival tissue. Attempt to remove all the retentive aspects for this sub-gingival extension, and just flick the last bit of IRM out with an explorer or scaler. Then you should be able to carefully slip on the matrix. You can even re-use the previous matrix if you thought ahead and kept it in the chart. This is a time-saver if the matrix was particularly hard to trim. However, if the matrix is beaten up, at the very least the old one will guide you as a template in preparing a new one.
The reward of this approach is healthy tissue in the operative field; there will not be chronic fulminating tissue whose biological width has been violated, nor the botchy, nerve-racking hemostasic crisis presenting when trying to place composite immediately without addressing biological width.
It is worth noting that the amount of osseous reduction required for a direct restoration is less than the equivalent for crown placement, where 1.5mm of ferrule is desired. This makes the direct composite restoration the more conservative of bone. It also in some cases is the only feasible restoration.