Document Type : Original Article


1 Department of Pediatric Dentistry, Torabinejad Dental Research Center, Isfahan University of Medical Sciences, Isfahan, Iran

2 Department of Operative Dentistry, Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan, Iran

3 Department of Pediatric Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.


Objective: Addition of vasoconstrictors to local anesthesia results in prolonged pain 
control. However, associated soft‑tissue anesthesia (STA) of the lips and tongue typically lasts 
3‑5 hours which is longer than required time for pain control after routine dental procedures 
can lead to inadvertent biting of the soft tissue, particularly in children. The present study 
aimed to evaluate phentolamine mesylate (PM) effect on duration of STA and incidence of 
soft‑tissue trauma after mandibular block injection.
Methods: This randomized, double‑blinded, controlled clinical trial included 54 patients 
with the age of 4‑11 years. In group 1 at the first visit, the children received ordinary local 
anesthetic (LA) consisting of lidocaine 2% and epinephrine 1:80,000 and the PM injection was 
performed 30 minutes later. At the second visit, the contralateral side received LA injection 
then the dental procedure was done and a sham injection was performed. In group 2 at the 
first visit, patients received control injection and at the second visit received PM injection. 
Then the reversal time for normal sensation of soft tissue, the vital signs, and the incidence 
of soft‑tissue trauma in a period of 3‑5 hours after injection were evaluated.
Findings: There was a statistically significant difference (P < 0.001) in recovery time of normal 
lip sensation between case and control groups and also between two groups (P < 0.003). 
Incidence of soft‑tissue trauma between case and control groups showed a statistically 
significant difference (P < 0.039).
Conclusion: PM can be considered as a safe and effective drug for reduction of reversal 
time of STA after dental procedures.


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