For most patients who experience a toothache, a visit to the dentist usually leads to a clear-cut direction of care and a predictable resolution of pain. The answer may be a simple repair, placement of a restoration, or may require root canal therapy (if the pulp is compromised by inflammation or infection). Pain relief with root canal therapy is often achieved after the first treatment session unless the tooth had been compromised for an extended period of time before treatment was initiated.
In fact, approximately 96% of all root canal procedures are successful and pain relief is achieved. The 4% that don’t fully resolve often remain symptomatic as a result of an irritated PDL that exhibits allodynia, a condition whereby normal stimuli produce pain. As a result, tooth pain may be experienced in a continuous fashion or emerge when the PDL is stimulated during chewing or tooth cleaning activities.
The PDL can also remain reactive due to a number of conditions that include an untreated canal, a tooth fracture, over-instrumentation of the apex, chemically induced irritation of the apex, autoimmune influences that impact connective tissue, and neuropathic conditions.
When a tooth fracture and an untreated canal have both been ruled out, we are essentially left to treat situations where nerve thresholds in the PDL have decreased in all the remaining scenarios. This, unfortunately, is a difficult process with few treatment options available.
Medications are the first and most likely therapy to help restore normal PDL reactivity. The oral medications of choice are often not easily tolerated by patients and require some creativity in terms of dosage, time of administration, and the need for polypharmacy. Common choices include low-dose tricyclic antidepressants inclusive of amitriptyline, nortriptyline and sinequan. Membrane stabilizers such as lyrica, gabapentin, baclofen and trileptal are frequently used, as well.
Dose-related decisions for all these medications vary from case-to-case and may at times require the use of liquid suspensions instead of pills to achieve a balance between effectiveness and side effects. At times benzodiazepines are added to the mix to quiet an upset brain, which often is the result of a chronic, disruptive pain problem.
When applicable, the use of topical medication preparations used intra or extra orally may be beneficial as well, with custom-made intra oral stents being used to hold the medication preparations in place. The time frame to continue these medications (if they help) is over many months, balancing benefits with side effects over the long term.
In situations where an autoimmune influence may be suspected as playing a role in reducing the threshold of peripheral nerves in the PDL, medications called biologics (Enbrel, Humira) may be required. These medications should be prescribed by a rheumatologist whose skills are often essential as part of the pain care team.
Surrounding these medications supportive therapies are often required, particularly if there is a history of awake and or sleep bruxism. Changing acquired jaw overuse behaviors during the day along with an oral appliance to protect the teeth from the impact of sleep bruxism is often important.
There are times, however, that response to these therapies is poor and pain continues. My overall rule at this point in time is to extract the teeth if after several months of care the patient still cannot chew on them. With a suspicion that the pain has a PDL origin, there should be full resolution of the pain once the teeth are removed. Fortunately, this is often the case. If, however, pain continues in the tooth extraction site, or in a neighboring tooth, additional dental interventions should be avoided.
The question then is: what is the next step?
Unfortunately, options from here on out are limited and experimental at best. With the knowledge that Botox has the capacity to stabilize neurosensory excitation, research is currently underway to determine whether the injection of Botox could somehow dampen electrical discharge from a sensitized PDL.
Protocol for both Botox and cannabis, however, remain poorly defined at the moment.
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