, Volume 17, Issue 4, pp 275-280
Date: 10 Nov 2012

A prospective randomized double-blind study to assess the latency and efficacy of Twin-mix and 2 % lignocaine with 1:200,000 epinephrine in surgical removal of impacted mandibular third molars: a pilot study

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A prospective randomized double-blind study was conducted to assess the latency and duration of pterygomandibular nerve block with a mixture of 1.8 ml 2 % lignocaine with 1:200,000 epinephrine and 1 ml of 4 mg dexamethasone and its impact on postoperative sequelae of surgical extraction of impacted mandibular third molars.

Material and methods

The study was conducted as a prospective randomized double-blind clinical trial on 20 patients with bilateral impaction of mandibular third molars. A total of 40 interventions were included for the study, 20 with 2 % lignocaine with 1:200,000 epinephrine (study group C, control) and 20 with the twin-mix (study group T, twin-mix), with a gap of 1 month between two interventions in a single patient. After injection of the anesthetic solution, the time to anesthetic effect, duration of anesthesia, and the need to re-anesthetize the surgical site were recorded. A 10-point visual analog scale (VAS) was used to assess the overall pain intensity while injecting the study drug, during surgery, and in the postoperative period. pH of the test anesthetic solutions was also determined using a pH meter.


Twin-mix was found to be more basic than 2 % lignocaine with 1:200,000 epinephrine. Mean VAS value for the pain/sting on local anesthetic injection/block was less in study group T. Time of onset of the local anesthetic was significantly less for the study group T, 51 ± 17.5 s when compared with patients in study group C (P less than 0.0001). The duration of soft tissue anesthesia was longer for all the patients in the study group T. On comparative evaluation between study group C and study group T, patients in the control group had more sever swelling and reduction in mouth opening in the postoperative period.


The addition of dexamethasone to lignocaine and its administration as an intra-space injection significantly shortens the latency and prolongs the duration of the soft tissue anesthesia, with improved quality of life in the postoperative period after surgical extraction of mandibular third molars.