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Odontalgia 317
single maxillary tooth. Infiltration is only necessary on the buccal side; lingual
injection increases discomfort without improving pain relief. 23 The relative
thickness of the mandibular bone, compared with the maxillary bone, provides
more of a barrier to diffusion of the injected agent (i.e. to the apical
nerve). Therefore, an inferior alveolar nerve block is recommended for
anesthesia of ipsilateral mandibular tooth-related OP. Both accessory innervation
and operator technique contribute to a failure rate of at least 20% for
inferior alveolar nerve blocks. 24
Although discussion of the procedural approach to providing regional
anesthesia is outside this text’s scope, some notes about medication selection
are in order. First, neither the selected local anesthetic nor its volume and
concentration appear to impact the rate of anesthetic success. 25,26 Second, as
long as some vasoconstricting epinephrine is coadministered, the concentration
(1:50 000, 1:80 000, 1:100 000) does not appear critical. 27 Finally,
bupivacaine’s extended duration of action, while advantageous in some
respects, is associated with buccal trauma risks related to prolonged anesthesia.
For safety reasons, we do not believe bilateral inferior alveolar nerve
blocks should be provided.
Injection of local anesthetics is a legitimate, well-studied mechanism for
providing relief of OP. This route may not be the approach of first choice in
every patient. However, it is sufficiently efficacious for most causes of dental
pain that it can be ethically recommended by the ED physician who is
concerned about potential (inappropriate) drug-seeking behavior on the
part of the patient with OP.
While there is insufficient evidence to recommend their routine use by the
acute care provider, locally injected opioids may in the future prove useful
for some cases of OP. One trial found that administration of low-dose (0.4 to
1.2 mg) morphine into the intraligamentary space provided relief in chronic,
but not in acute, OP. 28
Since there is no indication for routine addition of antibiotics for all
patients with OP, it is not surprising that penicillin therapy usually has no
impact on pain unless there is obvious infection. Trial evidence from OP
series shows that penicillin neither alleviates pain nor reduces the amount of
other analgesics required. 29,30