The dentist in general practice is most often confronted with pain of endodontic origin. Carious lesions (also secondary caries) are the primary culprit in 88% of cases, followed by cusp fracture, hypersensitive cervical areas, and traumatic occlusion. If the patient can identify the responsible tooth, or a radiograph reveals apical pathology, or there are additional clinical symptoms (e.g., sensitivity to percussion or a fistula) that provide clues about the affected tooth and the overall pathophysiologic situation, a treatment decision should be made quickly. If the patient reports radiating pain not directly related to a specific tooth, symptomatic treatment should be initiated.
Clinical studies have reported varying rates of success following direct pulp capping as an emergency treatment measure, ranging from 97.8% after 1.5 years to 61.4% 5 years later. In one clinical study, the success rate of 37% after 5 years dropped to only 13% after 10 years. Similar clinical studies following immediate extirpation of the exposed vital pulp found significantly higher success rates. For example, Rocke reported a 5-year success rate of 93% for all endodontically treated teeth, and a 10-year success rate of 81%. An exception to these excellent results were immature teeth with exposed pulps whose root growth was not yet complete.
Before attempting any management of pain of dental origin, the clinician must establish whether the patient has irreversible or reversible pulpitis or necrosis with or without apical involvement.
The transition into irreversible pulpitis is gradual, making precise diagnosis very difficult. In the first instance, the pulp chamber is not directly violated, but there may be a fractured restoration, exposed dentin, or an inadequate restoration. Pain can be elicited by stimuli such as cold, sweet, and sour and is of short duration.
The standard sensitivity test is positive, but there is no pain on percussion. A radiograph usually reveals deep caries or an old restoration with secondary caries; there are generally no radiographic signs of periapical involvement. Pulpal diagnosis has as its goal the maintenance of tooth vitality while simultaneously eliminating pain. This will usually involve complete removal of all old restorations and caries; in no case should residual caries be left untreated. Only by these measures is it possible to eliminate the possibility of additional pulpal irritation. When the patient has been pain-free for 48 hours, the tooth can be restored. If pain persists or increases in intensity, it indicates that irreversible pulpitis is present. In such cases, the root canal must be appropriately instrumented endodontically and later definitively restored.
An important component of all devitalization pastes is paraformaldehyde. It leads to coagulation and denaturation of cell wall proteins, which, finally, results in the arrest of all vital cell functions. The tissue becomes “fixed,” and this state of fixation is irreversible.
Animal experiments have demonstrated cellular toxicity, mutagenesis, carcinogenesis, and genotoxic changes. Using radioactively labeled paraformaldehyde, 14 days following pulpectomy, accumulation of metabolites in the liver has been observed. Systemic dissemination has also been observed in blood plasma, as well as in the lungs and kidneys.
With root canal fillings that are inadequately sealed, the result may be sequestrum formation in the adjacent bone, ultimately leading to tooth loss. Even with optimally sealed proximal restorations it is not always possible to inhibit the penetration of formaldehyde into adjacent bone, where damage can occur.
At the time of writing, there are no indications for devitalization of the pulpal tissues as “emergency” therapy. The numerous adverse effects far outweigh the potential beneficial effects.
Among emergency treatments of irreversible pulpitis, immediate endodontic treatment with extirpation and temporary filling provides the highest rate/>