Efficacy of liposome-encapsulated 0.5% ropivacaine in maxillary dental anaesthesia.

The aim of this study was to evaluate the effectiveness of liposome-encapsulated ropivacaine (0.5%) in dental anaesthesia. This randomised, double-blind, crossover, four-period treatment study included 40 volunteers who were given 1.8 ml of the following local anaesthetics into the buccal sulcus at the right level of the upper canine: 0.5% ropivacaine; 0.5% ropivacaine with 1:200,000 adrenaline; liposome-encapsulated 0.5% ropivacaine; and 2% lignocaine with 1:100,000 adrenaline. Onset of pulpal anaesthesia; the success of anaesthesia; and the duration of labial, gingival, and pulpal anaesthesia involving the upper right canine and first premolar were evaluated. At the end of each injection, volunteers rated the pain on injection on a visual analogue scale (VAS). Both ropivacaine and adrenaline, and lignocaine with adrenaline, were more successful anaesthetic agents than liposome-encapsulated ropivacaine or plain ropivacaine (p<0.05). There were no significant differences among the anaesthetic preparations in the onset of pulpal anaesthesia. Ropivacaine and adrenaline and lignocaine and adrenaline gave a significantly longer duration of pulpal anaesthesia. VAS showed no significant differences among the groups tested. The results showed that encapsulation of liposome did not improve the anaesthetic efficacy of ropivacaine.

Liposomal delivery system for topical anaesthesia of the palatal mucosa.

An effective topical agent to reduce pain during local anaesthesia of the palate is not yet available. The aim of the present study was to evaluate the efficiency of liposome-encapsulated ropivacaine in different concentrations for topical anaesthesia of the palatal mucosa. In this single-blinded, placebo-controlled, crossover study 40 (20 male) healthy volunteers were randomised to be given: liposome-encapsulated 2% ropivacaine, liposome-encapsulated 1% ropivacaine, a eutectic mixture of 2.5% lidocaine and 2.5% prilocaine (EMLA), and liposomal placebo gel, topically on to the palatal mucosa of the right canine region for 5 min each, at four different sessions. Pain associated with insertion of a 30G needle, and with injection of a local anaesthetic, was rated on a visual analogue scale (VAS). The effect of liposomal ropivacaine 1% and 2% did not differ from that of placebo (p=0.3 and p=0.1, respectively) in reducing pain during insertion of the needle. Lower VAS were obtained with EMLA. In this group VAS were lower in women than men (p=0.007). There was no difference in VAS among groups (p=0.3) as far as injection of the local anaesthetic was concerned. In conclusion, liposomal-encapsulated ropivacaine formulations did not reduce the pain of insertion of a needle into the palatal mucosa. None of the anaesthetic formulations tested, including the positive control (EMLA), were effective in reducing the pain of an injection of local anaesthetic compared with placebo.

Ulceration of gingival mucosa after topical application of EMLA: report of four cases.

This study reports four cases of mucosa ulceration after a 30-minute application of EMLA (0.3 g) as a topical anaesthetic in dentistry. The subjects returned the next day with a white ulceration and desquamation on the application site. EMLA cream should not be applied to the oral mucosa for 30 minutes.

Articaine and lignocaine efficiency in infiltration anaesthesia: a pilot study.

AIM: The purpose of this study was to evaluate the onset of action of pulpal and soft tissue anaesthesia, and pain experience after buccal and palatal infiltrative injections with 4% articaine with 1:100,000 adrenaline, and 2% lignocaine with 1:100,000 adrenaline. METHOD: A double blind cross-over study was conducted with 20 healthy adult subjects who, in two appointments at least two weeks apart, randomly received an infiltration anaesthesia with the solutions in the buccal and palatal regions of the upper right canine. The tooth was tested with a pulp tester before (to establish its baseline response), and after the injection, until return to the base threshold level. The pain experience caused by palatal injection was verified by the visual analogue scale (VAS). Data were analysed using Wilcoxons test (alpha = 0.05). RESULTS: There were no significant statistical differences between the solutions with respect to VAS (p = 0.45), onset of action (p = 0.80) and pulpal (p = 0.08) and soft tissue (p = 0.18) anaesthesia duration, although pulpal anaesthesia may have reached statistical significance if a higher number of volunteers had been used. CONCLUSION: Under the conditions of this study it can be concluded that both anaesthetic solutions showed similar pain experience.

Allergic reaction after rubber dam placement.

In the last few years allergic reactions to natural rubber latex (NRL) have increased in dental practice affecting both the dental team and patients. Some case reports discuss the potential risks of hypersensitivity to NRL products. An adverse patient reaction after dental rubber dam placement is reported. About 1 min after the isolation of the tooth with a rubber dam the patient presented signs and symptoms of hypersensitivity. Oxygen and intravenous hydrocortisone were administered and the patient kept under observation. After 2 h she had stable vital signs and no more allergics symptoms. It is unclear whether components of the NRL dam or the cornstarch powder incorporated with the rubber dam was responsible for the allergic reaction. Dentists must be aware of the health problem and be prepared for an adequate management in dental practice.

Acute toxicity (LD50 and CD50) of lidocaine and prilocaine in combination with adrenaline and felypressin.

The toxicity of the combination of vasoconstrictors to local anaesthetic solutions has been debated since its first use in the beginning of this century. A combination of two vasoconstrictors to a local anaesthetic has been proposed by some researchers. In this study they were evaluated the acute toxicity (lethal dose 50%, convulsion dose 50%) and latency times of loss of righting reflex and convulsion as well as the duration of convulsion) of 2% lidocaine or 3% prilocaine, when administered in combination with adrenaline and felypressin at various concentrations. Lethal dose 50% studies showed that for both anaesthetics the solutions with higher concentrations of adrenaline were more toxic. The opposite was observed in the convulsion dose 50% studies. No alterations were observed in the control groups. All lidocaine solutions increased the latency of loss of righting reflex. The latency of convulsion was increased in some groups, but once the convulsion was achieved there was no difference in its duration. There was no statistical difference among prilocaine groups for any of the variables studied. Based on the experimental model studied, it was concluded that there is no advantage in the association of two vasoconstrictors concerning the toxicity of lidocaine and prilocaine solutions.

Blood glucose determination in normal and alloxan-diabetic rats after administration of local anesthetics containing vasoconstrictors.

Normal and alloxan-diabetic rats were injected submucously in the posterior region of the upper jaw with bupivacaine (1.28 mg/kg) containing adrenaline (0.0012 mg/kg), or lignocaine (5.14 mg/kg) containing noradrenaline (0.005 mg/kg). Blood glucose was determined at zero (before administration), 0.5, 1, 2, 3 and 4 hours after the administration of the anesthetics. Statistical analysis (ANOVA and Tukey's test, P < 0.05) showed significant differences between treatments at 1 hour in normal rats. Bupivacaine with adrenaline induced a significantly greater blood glucose level than lignocaine with noradrenaline. The effect was significant but of short duration. In alloxan-diabetic rats, anesthetics containing adrenaline or noradrenaline did not induce increased blood glucose levels.