Liposome-encapsulated ropivacaine for topical anesthesia of human oral mucosa.
BACKGROUND
The elimination of pain caused by needle insertion for local anesthesia would be a significant advance in dentistry.


METHODS
In this blinded cross-over study we evaluated the efficacy of liposome-encapsulated ropivacaine for topical anesthesia. Thirty healthy volunteers received 60 mg topical anesthetics: Liposome-encapsulated 1% ropivacaine, 1% plain ropivacaine, 2.5% lidocaine and 2.5% prilocaine mixture (EMLA), and 20% benzocaine gel, in the buccal fold of the upper-right canine for 2 min in different sessions. After insertion of 30-G needles, pain was rated on a visual analog scale (VAS). A pinprick test was used to measure the duration of topical anesthesia. The pulpar response was assessed by an electric pulp tester.


RESULTS
VAS median and interquartile range (in cm) were 0.8 (0.4-1.5), 1.6 (0.8-2.6), 1.1 (0.3-2.7), 2.2 (0.9-2.9) for liposome-encapsulated ropivacaine, ropivacaine, EMLA, and benzocaine groups, respectively. The liposome-encapsulated ropivacaine group showed lower VAS mean values when compared with the benzocaine group (P = 0.0205). The median values and interquartile range for the duration of soft tissue anesthesia were 11 (7-14), 6.5 (4-11), 14 (11-16), and 7 (6-9) min for liposome-encapsulated ropivacaine, ropivacaine, EMLA, and benzocaine groups, respectively. EMLA and liposome-encapsulated ropivacaine were just as efficient for reducing pain, and showed longer soft tissue anesthesia when compared to the other local anesthetics (P = 0.0001).


CONCLUSIONS
Liposomal-encapsulated 1% ropivacaine gel was equivalent to EMLA for reducing pain during needle insertion and for the duration of soft tissue anesthesia. None of the topical anesthetics was effective for inducing pulpal anesthesia.
Franz-Montan
Michelle
M
Department of Physiological Sciences, Dentistry School of Piracicaba, Piracicaba, SP, Brazil.
Silva
André L R
AL
Cogo
Karina
K
Bergamaschi
Cristiane de C
Cde C
Volpato
Maria C
MC
Ranali
José
J
de Paula
Eneida
E
Groppo
Francisco C
FC
D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000577:Amides / Q000008:administration & dosage* / Q000737:chemistry; D000772:Anesthesia, Local / Q000379:methods*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008081:Liposomes; D008297:Male; D009061:Mouth Mucosa / Q000187:drug effects* / Q000378:metabolism; D010147:Pain Measurement / Q000187:drug effects; D000077212:Ropivacaine
D000577:Amides; D008081:Liposomes; D000077212:Ropivacaine