Injection pain of bupivacaine with epinephrine vs. prilocaine plain.

Background: Prilocaine plain has been described in the literature as causing less pain on injection than bupivacaine with epinephrine, possibly because of the higher pH of the prilocaine anesthetic solution.

Methods: In a double-blind study design, 681 consecutive patients in a general dental practice received maxillary buccal infiltration, posterior palatal infiltration or inferior alveolar block injections, administered under clinical conditions by one of two dentists. Immediately after injection, patients rated the pain from each injection on a six-point scale. The pain response was analyzed according to treating dentist, location of injection, patient's sex and anesthetic administered.

Results: The reported pain on injection of bupivacaine with epinephrine was significantly greater than that of prilocaine plain. Patients reported no significant difference in pain at different injection locations, except that palatal injections caused significantly more reported pain than did anterior maxillary infiltration, posterior maxillary infiltration or inferior alveolar block injections.

Conclusions: Under clinical conditions, the injection of bupivacaine with epinephrine causes significantly more perceived pain than does the injection of prilocaine plain. Clinical Implications. Bupivacaine with epinephrine and prilocaine plain have certain advantages and disadvantages that should be considered before choosing an anesthetic for a dental procedure. A disadvantage of bupivacaine with epinephrine is that it produces more perceived pain than does prilocaine plain.