Intraoral topical anesthesia

Mirrors and toothaches: commonplace manipulations of non-auditory feedback availability change perceived speech intelligibility

This paper investigates the impact of two non-technical speech feedback perturbations outside the auditory modality: topical application of commercially-available benzocaine to reduce somatosensory feedback from speakers' lips and tongue tip, and the presence of a mirror to provide fully-detailed visual self-feedback. In experiment 1, speakers were recorded under normal quiet conditions (i.e., baseline), then again with benzocaine application plus auditory degradation, and finally with the addition of mirror feedback. Speech produced under normal and both feedback-altered conditions was assessed via naïve listeners' intelligibility discrimination judgments. Listeners judged speech produced under bisensory degradation to be less intelligible than speech from the un-degraded baseline, and with a greater degree of difference than previously observed with auditory-only degradation. The introduction of mirror feedback, however, did not result in relative improvements in intelligibility. Experiment 2, therefore, assessed the effect of a mirror on speech intelligibility in isolation with no other sensory feedback manipulations. Speech was recorded at baseline and then again in front of a mirror, and relative intelligibility was discriminated by naïve listeners. Speech produced with mirror feedback was judged as less intelligible than baseline tokens, indicating a negative impact of visual self-feedback in the absence of other sensory manipulations. The results of both experiments demonstrate that relatively accessible manipulations of non-auditory sensory feedback can produce speech-relevant effects, and that those effects are perceptible to naïve listeners.

Effectiveness and Tolerability of a New Formulation of a Topical Anesthetic in Reduction of Pain and Parents’ Satisfaction in Pediatric Dentistry

The aim of the present study was to test a new topical anesthetic gel with a different formulation (10% lidocaine, 10% prilocaine) to analyze its effectiveness in pain control, during the subsequent injection of local anesthetic, and the presence of any side effects. Methods: The study’s research design was a randomized controlled clinical trial on 300 children, aged 5–8 years, divided into two groups, each of 150 patients, according to pre-injection procedures (presence or absence of topical anesthesia). The injection pain was analyzed using the Wong-Baker Faces Pain Rating Scale (PRS) and the Face, Legs, Activity, Cry, Consolability Scale (FLACC). At the end of the procedures, patients’ parents’ satisfaction was recorded. The data were analyzed using the Student’s T test, Mann–Whitney U test and Chi-square test. Results: There were statistically significant differences between the two groups both in the PRS and FLACC ratings. Both in subjective and objective pain evaluations, significantly higher pain ratings were observed in the group without topical anesthesia. There was also a statistically significant difference in terms of patients’ parents’ judgment, as in the group with the use of topical anesthetic the level of parental satisfaction is statistically higher. Conclusion: The experimental anesthetic has proved very effective in its use as a topical gel in both pain measurement scales, thus validating its use on the oral mucosa, for its pharmacological and psychological effect, in the total absence of local and systemic side effects.

A Randomized Controlled Trial Comparing Two Different Local Intraurethral Anesthetics in Optical Internal Urethrotomy at the Outpatient Clinic

OBJECTIVE

To assess feasibility and efficacy of local topical urethral anesthesia at optical internal urethrotomy (OIU) in patients with anterior and posterior urethral strictures at outpatient clinic.

METHODS

One hundred and twenty eight patients were prospectively randomized to perform OIU with intraurethral prilocaine solution (group 1 = 64 patients) or intraurethral lidocaine gel (group 2 = 64 patients). Visual analog scale was used for procedure related pain evaluation at the beginning, during, and one hour after the procedure. All patients had follow-ups for a minimum of 12 months. Treatment failure was defined as Qmax < 12ml/sec at uroflowmetry and observed urethral stricture on cystoscopy.

RESULTS

The overall success rate of the OIU was 75.8%. The intraoperative mean visual analogue score in group 2 (5,1 ± 1,77) was significantly higher than the group 1 (3.7 ± 1.9) (P = 0.0001). The median time to stricture recurrence was 9.2 months (range 1-13 months). Stricture recurrences were noted in 15 patients in Group 1 and 16 patients in Group 2 during the follow-up period.

CONCLUSION

Prilocaine solution as a local anesthetic is a better option than intraurethral lidocaine gel in the OIU procedure and allows successful OIU to be performed in outpatient clinic. It can be preferred as a local anesthetic for OIU, particularly in unfit patients for general/regional anesthesia. Although it provides successful pain relief, it still cannot prevent experiencing moderate or severe pain in a group of patients. More studies about more effective local anesthetics for pain relief during OIU at the outpatient clinic are required.

Present status and future directions - Mechanisms and management of local anaesthetic failures

Pain control during root canal treatment is of utmost importance for both the patient and the dental practitioner and many studies have investigated ways of overcoming problems with gaining adequate anaesthesia during treatment. The PubMed and Cochrane databases were searched for evidence-based studies regarding local anaesthesia for root canal treatment. Many variables, including premedication, pain during needle insertion, pain on injection, premedication with various types of drugs, volume of anaesthetic solutions, supplemental anaesthetic techniques, and additives to the anaesthetic solutions, may influence pain perception during root canal treatment. Differences between teeth with healthy pulps versus those with irreversible pulpitis should be considered when the effects of variables are interpreted. There are several concerns regarding the methodologies used in studies that have evaluated anaesthesia success rates. There are some conditions that may help to predict a patient's pain during root canal treatment and these conditions could be overcome either by employing methods such as premedication with a non-steroidal anti-inflammatory drug prior to the treatment visit or by using supplementary anaesthetic techniques before or during the treatment. However, authors need to be more careful when reporting details of their studies to reduce concerns regarding their study bias.

2.5% EMLA Versus 2% Lignocaine with Adrenaline Injection in Small Oral Mucosal Biopsies: A Parallel Group Randomized Controlled Trial

Trial Design

The study was designed as an open label randomized comparative parallel group design with a 1:1 allocation ratio.

Methods

All consecutive patients reporting for small biopsies (incisional or excisional) who gave written informed consent were included in the study between October 2018 and October 2019. They were randomized into two groups, Group A and Group B both receiving intervention in the form of 2.5% EMLA cream and 2% Lignocaine with 1:80,000 Adrenaline injection respectively, to anaesthetise tissue for small mucosal biopsies in the oral cavity.

Results

EMLA was found to be as effective as lignocaine infiltration with a completely painless application and higher satisfaction for overall comfort during procedure. The duration required to achieve anaesthesia was however more. A particular subgroup of pathology was found to be completely resistant to anaesthesia by EMLA.

Conclusion

We recommend the use of EMLA as a sole anaesthetic in small mucosal biopsies and shavings in all patients. We suggest it as a higher and first line recommendation for anaesthesia in needle phobic patients and children.

To Compare and Analyze the Potency of two Topical Anesthetic Gels in Reducing Inferior Alveolar Injection Pain in Children of 8-12 Years: A Double-Blinded Clinical Trial

Aim:

To compare and analyze the clinical adequacy of two topical anesthetic gels, Precaine (8% lidocaine + 0.8% dibucaine) and Precaine B (20% benzocaine) in children before intraoral local anesthetic injections.

Materials and Methods:

This clinical study included thirty children who needed an inferior alveolar nerve block. They were divided into three groups: Group A: Precaine topical gel group, Group B: Precaine B topical gel Group, Group C: no anesthetic topical gel group (control group). These two effective topical gels were applied before giving intraoral local anesthesia, and afterward, the child's pain response was surveyed utilizing the Wong-Baker Faces Pain Rating Scale. The scores obtained were subjected to statistical analysis.

Results:

Intergroup comparison showed a significant mean difference between the control group and Precaine group (P > 0.05) as well as Precaine B group (P > 0.05). However, there is no significant difference obtained between Group A and Group B (P < 0.05).

Conclusion:

It is psychologically and clinically beneficial to apply a topical anesthetic agent before injecting any intraoral anesthesia. In this study, both anesthetic gels showed a nonsignificant difference in reducing inferior alveolar injection pain, but Precaine B shows more promising results than Precaine.

Comparative Evaluation of Two Different Topical Anesthetic Agents in Controlling Pain during Intraoral Local Anesthetic Administration in Children: A Split-mouth Triple-blinded Randomized Clinical Trial

Aim

To compare the efficacy of lignocaine and benzocaine when applied as a topical anesthetic before intraoral local anesthetic administration in children.

Materials and methods

Forty-four patients aged between 4 years and 10 years indicated for pulp therapy of primary teeth under inferior alveolar nerve block were selected for this study. The participants were randomly allocated into two groups of 22 each. Group I (lignocaine gel) and group II (benzocaine gel) were applied before inferior alveolar nerve block. The pain scale was assessed by a trained examiner using the visual analog scale (VAS) and sound eye motor scale.

Results

Lignocaine when used as a topical anesthetic agent showed lower mean scores under both the pain scales when compared with benzocaine but the results were statistically insignificant.

Conclusion

Lignocaine and benzocaine are equally effective when applied as a topical anesthetic agent. But lignocaine was more preferred in taste when compared with benzocaine.

How to cite this article

Kotian N, Mani G, Ramakrishnan M. Comparative Evaluation of Two Different Topical Anesthetic Agents in Controlling Pain during Intraoral Local Anesthetic Administration in Children: A Split-mouth Triple-blinded Randomized Clinical Trial. Int J Clin Pediatr Dent 2021;14(2):180–182.

Does the use of topical anesthetics reduce the perception of pain during needle puncture and anesthetic infiltration? Systematic review and meta-analysis of randomized controlled trials

The objective of this systematic review was to assess whether the use of topical anesthetics reduces the perception of pain during puncture and anesthetic infiltration. Twenty-two randomized controlled clinical trials, published in English on or before August 6, 2020, were found in the PubMed/MEDLINE, Scopus, and Cochrane Library databases. Risk of bias was determined for randomization and other issues. A total of 1029 patients were evaluated using parameters such as type of topical anesthetic, application site, and pain (measured on a scale). Some studies assessed more than one topical anesthetic. Seventeen of them showed a reduction in pain from needle puncture and four from infiltration. Meta-analyses for some results showed considerable statistical heterogeneity. Regarding pain during needle puncture of the maxilla, statistically significant differences were observed in the topical anesthetics group, in both the vestibular (P = 0.0002) and palatal (P = 0.005) region. This was different from the mandible, for which there was no statistically significant difference (P = 0.07). With regard to pain caused by anesthetic infiltration in the maxilla, there was no difference in the use of anesthetic in relation to the control group (P = 0.11). Given these findings, using topical anesthetics only relieves pain during needle puncture and in the maxilla. PROSPERO 2020: CRD42020206362.

The effect of vibration stimulation on intramuscular injection pain and patient satisfaction: Single-blind, randomised controlled study

AIMS AND OBJECTIVES

The aim of this study was to assess the effect of vibration stimulation application in ventrogluteal region on intramuscular injection pain and patient satisfaction.

BACKGROUND

Intramuscular injection pain caused distress for the patients and affected their compliance with the treatment.

DESIGN

This was a prospective, single-blind, cross-over study. The study complied with the guidelines of Consolidated Standards of Reporting Trials (CONSORT).

METHODS

Eighty-four patients who applied to the adult emergency department received an intramuscular injection of amoxicillin\ cefuroxime sodium to the ventrogluteal site with and without vibration in a random order following a standard procedure by the same investigator. Pain and satisfaction were assessed immediately after the injection with Visual Analogue Scale (VAS), by a researcher blinded to the study. The data were evaluated using mean, standard deviation, percentage, Student's t-test, paired sample t-test, linear regression analysis and generalised linear mixed model.

RESULTS

A total of 174 injections were analysed. The result of the study revealed that vibration decreased the severity of pain and increased the patient satisfaction.

CONCLUSIONS

Vibration is a non-pharmacologic approach, which can be effective in decreasing the injection pain and increasing patient satisfaction.

RELEVANCE TO CLINICAL PRACTICE

Intramuscular injection is the most frequently used nursing practice in the clinic. The use of vibration in decreasing pain due to intramuscular applications can help increase the self-confidence of nurses and the quality of the care they provide.

A Proof-of-concept Study Using Quantitative Sensory Threshold Analysis to Compare Two Intraoral Topical Anesthetics

PURPOSE

CTY-5339A is an investigational topical anesthetic spray containing 14% benzocaine/2% tetracaine in a metered canister. Each spray delivers ∼0.2 mL of solution. This double-blind, randomized, crossover study compared the local anesthetic effect of CTY-5339A versus 14% benzocaine alone by using 2 quantitative sensory threshold experimental pain paradigms on the maxillary gingiva: pin prick test pain intensity (PPT PI) and heat pain threshold (HPT).

METHODS

American Society of Anesthesiology Class 1 and 2 subjects (N = 50) were enrolled in this study. To qualify for the study, subjects were tested on the anterior maxillary gingiva with both PPT and HPT. Subjects had to report a PPT PI of ≥3 on a 0 to 10 numeric pain intensity scale on 1 of 2 consecutive pin pricks separated by 10 s, with at least one score ≥4. After PPT, mean HPT following 2 ramps in the same location had to be ≤ 46.5 °C, with each ramp beginning at 35 °C and an automatic cutoff of 50.6 °C. For treatment visits, subjects were randomly administered either 1 spray of CTY-5339A or 14% benzocaine to the anterior maxillary gingiva within 3 weeks of screening and then the alternative treatment 5 days to 2 weeks later. PPT PI and HPT were recorded immediately before drug application. After drug administration, PPT PI was recorded every minute through 5 min. Commencing at 5 min, PPT PI and HPT were recorded every 5 min through 60 min. For assessment of methemoglobin concentrations, venous blood (5 mL) was drawn from the antecubital fossa both before and 60 min after drug application. Oxygen saturation was recorded via pulse oximetry at baseline and every 10 min.

FINDINGS

The AUCs for pain intensity difference from 0-30 and 0-60 min after PPT and HPT differences were significantly greater (P < 0.0001) for CTY-5339A compared with 14% benzocaine. Multiple time points on the time-action curves for PPT PI difference and HPT difference statistically (P < 0.05) favored CTY-5399A. Methemoglobin and oxygen saturation levels did not change compared with baseline after dosing with either treatment.

IMPLICATIONS

Recommended doses of CTY-5339A provided significantly more profound and sustained local anesthesia than 14% benzocaine when applied to the maxillary gingiva. Significant changes in methemoglobin or oxygen saturation concentrations did not occur for either drug. ClinicalTrials.gov identifier: NCT03233737.

Hybrid Hydrogel Composed of Polymeric Nanocapsules Co-Loading Lidocaine and Prilocaine for Topical Intraoral Anesthesia

This study reports the development of nanostructured hydrogels for the sustained release of the eutectic mixture of lidocaine and prilocaine (both at 2.5%) for intraoral topical use. The local anesthetics, free or encapsulated in poly(ε-caprolactone) nanocapsules, were incorporated into CARBOPOL hydrogel. The nanoparticle suspensions were characterized in vitro in terms of particle size, polydispersity, and surface charge, using dynamic light scattering measurements. The nanoparticle concentrations were determined by nanoparticle tracking analysis. Evaluation was made of physicochemical stability, structural features, encapsulation efficiency, and in vitro release kinetics. The CARBOPOL hydrogels were submitted to rheological, accelerated stability, and in vitro release tests, as well as determination of mechanical and mucoadhesive properties, in vitro cytotoxicity towards FGH and HaCaT cells, and in vitro permeation across buccal and palatal mucosa. Anesthetic efficacy was evaluated using Wistar rats. Nanocapsules were successfully developed that presented desirable physicochemical properties and a sustained release profile. The hydrogel formulations were stable for up to 6 months under critical conditions and exhibited non-Newtonian pseudoplastic flows, satisfactory mucoadhesive strength, non-cytotoxicity, and slow permeation across oral mucosa. In vivo assays revealed higher anesthetic efficacy in tail-flick tests, compared to a commercially available product. In conclusion, the proposed hydrogel has potential for provision of effective and longer-lasting superficial anesthesia at oral mucosa during medical and dental procedures. These results open perspectives for future clinical trials.

Lack of Methemoglobin Elevations After Topical Applications of Benzocaine Alone or Benzocaine Plus Tetracaine to the Oral Mucosa

PURPOSE

This study evaluated changes in methemoglobin and oxygen saturation concentrations after the administration of recommended doses of 14% benzocaine alone or 14% benzocaine combined with 2% tetracaine.

METHODS

American Society of Anesthesiology class 1 and 2 subjects (n = 40) were enrolled in this modified crossover study. Subjects were administered 0.2 mL of 14% benzocaine alone, 0.2 mL of 14% benzocaine plus 2% tetracaine, or 0.4 mL of 14% benzocaine plus 0.2% benzocaine to their cheek mucosa. Venous blood (5 mL) was drawn from the antecubital fossa before and 60 minutes after drug application for methemoglobin analyses. Oxygen saturation was also recorded via pulse oximetry at baseline and every 10 minutes through 60 minutes after drug application.

FINDINGS

Methemoglobin and oxygen saturation levels did not change from baseline after the administration of benzocaine alone or when combined with tetracaine.

IMPLICATIONS

Recommended doses of benzocaine or benzocaine combined with tetracaine when applied to the cheek mucosa do not induce even clinically insignificant elevations in methemoglobin levels. Metered dosing, such as that used in this study, can help avoid this overdose phenomena with these drugs. ClinicalTrials.gov identifier: NCT02908620.

Review: allergic contact stomatitis

Allergic contact stomatitis (ACS) is an oral mucosal immunoinflammatory disorder variably characterized clinically by erythematous plaques, vesiculation, ulceration, and/or hyperkeratosis and by pain, burning sensation, or itchiness. ACS is brought about by a T cell-mediated, delayed hypersensitivity immune reaction generated by a second or subsequent contact exposure of an allergen with the oral mucosa, in a genetically susceptible, sensitized subject. Lichenoid contact reaction is a variant of ACS brought about by direct contact with the oral mucosa of certain metals in dental restorations. The features of ACS are neither clinically nor histopathologically specific, so the diagnosis is usually presumptive and can only be confirmed by resolution of the inflammation after withdrawal or removal of the suspected causative allergen. When ACS is suspected but an allergen cannot be identified, patch testing is necessary. In persistent cases, topical corticosteroids are the treatment of choice, but for severe and extensive lesions, systemic corticosteroid and systemic antihistamines may be indicated. In this short review, we highlight the clinical, immunologic, and histopathological features of ACS, and provide some guidelines for diagnosis and management.

Recent advances in topical anesthesia

Topical anesthetics act on the peripheral nerves and reduce the sensation of pain at the site of application. In dentistry, they are used to control local pain caused by needling, placement of orthodontic bands, the vomiting reflex, oral mucositis, and rubber-dam clamp placement. Traditional topical anesthetics contain lidocaine or benzocaine as active ingredients and are used in the form of solutions, creams, gels, and sprays. Eutectic mixtures of local anesthesia cream, a mixture of various topical anesthetics, has been reported to be more potent than other anesthetics. Recently, new products with modified ingredients and application methods have been introduced into the market. These products may be used for mild pain during periodontal treatment, such as scaling. Dentists should be aware that topical anesthetics, although rare, might induce allergic reactions or side effects as a result of an overdose. Topical anesthetics are useful aids during dental treatment, as they reduce dental phobia, especially in children, by mitigating discomfort and pain.

Comparison of lidocaine/tetracaine cream and lidocaine/prilocaine cream for local anaesthesia during laser treatment of acne keloidalis nuchae and tattoo removal: results of two randomized controlled trials

BACKGROUND

Pain is a common adverse effect of dermatological laser procedures. Currently, no standard topical anaesthetic cream exists for deeper dermal laser procedures.

OBJECTIVES

To compare the efficacy of lidocaine/tetracaine cream and lidocaine/prilocaine cream in reducing self-reported pain during deeper dermal laser treatment of acne keloidalis nuchae (AKN) and tattoos.

METHODS

We conducted two randomized, double-blind, controlled clinical trials with intrapatient, split-lesion designs: study A included patients with AKN (n = 15); study B included patients with black tattoos (n = 15). The primary end point was the patients' self-reported pain on a 10-cm visual analogue scale (VAS). Secondary objectives were the percentage of patients with adequate pain relief, willingness to pay €25 for the cream that provided the best pain relief and safety of the creams.

RESULTS

In both studies, VAS scores were lower for lidocaine/prilocaine cream, with a mean VAS difference in study A of 1·9 [95% confidence interval (CI) 1·0-2·8] and in study B of 0·6 (95% CI -0·7 to 1·9). In study A, adequate pain relief was achieved in 13% (n = 2) with lidocaine/tetracaine cream vs. 73% (n = 11) with lidocaine/prilocaine cream (P = 0·004), and in study B in 53% (n = 8) vs. 80% (n = 12), respectively (P = 0·289). In study A, 47% (n = 7) were willing to pay an additional €25 vs. 73% (n = 11) in study B. No serious adverse events occurred.

CONCLUSIONS

Lidocaine/prilocaine cream under plastic occlusion is the preferred topical anaesthetic during painful laser procedures targeting dermal chromophores.

Efficacy of Benzocaine 20% Topical Anesthetic Compared to Placebo Prior to Administration of Local Anesthesia in the Oral Cavity: A Randomized Controlled Trial

The aim of the present study was to compare the effects of a topical anesthetic to a placebo on pain perception during administration of local anesthesia in 2 regions of the oral cavity. A split-mouth, double-blind, randomized clinical trial design was used. Thirty-eight subjects, ages 18-50 years, American Society of Anesthesiologists I and II, received 4 anesthetic injections each in regions corresponding to the posterior superior alveolar nerve (PSA) and greater palatine nerve (GPN), totaling 152 sites analyzed. The side of the mouth where the topical anesthetic (benzocaine 20%) or the placebo was to be applied was chosen by a flip of a coin. The needle used was 27G, and the anesthetic used for administration of local anesthesia was 2% lidocaine with 1:100,000 epinephrine. After receiving the administration of local anesthesia, each patient reported pain perception on a visual analog scale (VAS) of 100-mm length. The results showed that the topical anesthetic and the placebo had similar effects: there was no statistically significant VAS difference between the PSA and the GPN pain ratings. A higher value on the VAS for the anesthesia of the GPN, relative to the PSA, was observed for both groups. Regarding gender, male patients had higher values on the VAS compared with female patients, but these differences were not meaningful. The topical anesthetic and the placebo had similar effects on pain perception for injection of local anesthesia for the PSA and GPN.

A new protocol to evaluate the effect of topical anesthesia

This double-blind, placebo-controlled, randomized cross-over clinical experimental study tested the reliability, validity, and sensitivity to change of punctuate pain thresholds and self-reported pain on needle penetration. Female subjects without orofacial pain were tested in 2 sessions at 1- to 2-week intervals. The test site was the mucobuccal fold adjacent to the first upper right premolar. Active lidocaine hydrochloride 2% (Dynexan) or placebo gel was applied for 5 minutes, and sensory testing was performed before and after application. The standardized quantitative sensory test protocol included mechanical pain threshold (MPT), pressure pain threshold (PPT), mechanical pain sensitivity (MPS), and needle penetration sensitivity (NPS) assessments. Twenty-nine subjects, mean (SD) age 29.0 (10.2) years, completed the study. Test-retest reliability intraclass correlation coefficient at 10-minute intervals between examinations was MPT 0.69, PPT 0.79, MPS 0.72, and NPS 0.86. A high correlation was found between NPS and MPS (r = 0.84; P < .001), whereas NPS and PPT were not significantly correlated. The study found good to excellent test-retest reliability for all measures. None of the sensory measures detected changes in sensitivity following lidocaine 2% or placebo gel. Electronic von Frey assessments of MPT/MPS on oral mucosa have good validity.

Efficacy of lignocaine in gel and spray form during buccal infiltration anesthesia in children: a randomized clinical trial

AIM

To compare the efficacy of 15% lignocaine spray and 8% lignocaine gel as a topical anesthetic, in reducing pain, during buccal infiltration in children.

MATERIALS AND METHODS

Forty-two patients aged between 7 and 12 years requiring restorative procedures/extraction/pulp therapy of primary/ permanent teeth in the maxillary arch, under buccal infiltration anesthesia were selected for the study. The participants were randomly allocated into 2 groups of 21 each. In group A, 8% lignocaine gel and in group B, 15% lignocaine spray was applied prior to buccal infiltration. Pain was assessed using Wong-Baker faces pain rating scale (WBFPRS) and faces legs activity cry and consolability (FLACC) painscale.

RESULTS

Pearson's chi-square test revealed that there was no significant difference in the FLACC scores of the two groups (p = 0.54). Independent t-test demonstrated that there was no significant difference in Wong-Bakers faces pain score between the two agents (p = 0.07).

CONCLUSION

There is no significant difference in the efficacy of 15% lignocaine spray and 8% lignocaine gel as a topical anesthetic in controlling pain during buccal infiltration anesthesia, in children.

In vitro evaluation of mucoadhesive films for gingival administration of lidocaine

The aim of this study was the optimization of a lidocaine-based film formulation for the prevention of pain from needle prick during the injection of local anesthetic in dentistry. Film performances were evaluated in vitro by studying lidocaine permeation across pig esophageal epithelium as model for nonkeratinized buccal mucosa. The results obtained showed that the molecular weight of the film-forming polymer had no effect on lidocaine transport. The introduction of the adhesive Plastoid® into the film determined a significant increase of drug permeation rate, which was further improved by the addition of Azone®. On the contrary, the effect of sodium taurocholate was negligible.

Effect of eutectic mixture of local anesthetics on pain perception during scaling by ultrasonic or hand instruments: a masked randomized controlled trial

BACKGROUND

The aims of this study are to evaluate the efficacy of a eutectic mixture of local anesthetic (EMLA) cream on pain perception during scaling and to compare the intensities of pain provoked by hand and ultrasonic instruments.

METHODS

Forty subjects with chronic gingivitis or periodontitis were enrolled in the study. In this randomized, split-mouth, controlled, masked clinical trial, each of the four quadrants in subjects was randomly assigned to receive one of the following protocols: scaling with an ultrasonic scaler with or without the application of the EMLA cream or scaling with a Gracey curet with or without the application of the EMLA cream. Pain levels after each quadrant of scaling were assessed with a visual analog scale (VAS; 0 to 100 mm) and verbal rating score (VRS; 0 to 4). All subjects were recalled to detect any complications after 24 hours.

RESULTS

The mean VAS and VRS when EMLA cream was applied (18.39 ± 14.47 mm and 0.95 ± 0.69) were significantly lower (P <0.001 for VAS and VRS) compared to when EMLA cream was not used (26.54 ± 16.46 mm and 1.30 ± 0.75). The mean VAS and VRS of the ultrasonic scaler group (20.43 ± 16.40 mm and 0.98 ± 0.76) were significantly lower (P = 0.024 for VAS; P = 0.003 for VRS) than those of the Gracey curet group (24.50 ± 15.17 mm and 1.28 ± 0.69). None of the subjects showed adverse effects after EMLA-cream application.

CONCLUSION

Although most patients experienced limited pain during scaling, a significant reduction of pain is achieved by using EMLA cream and ultrasonic scaler.

Aspirations and solutions--a 20 year journey through dental local anaesthetics

This paper describes clinical and laboratory investigations concerned with the delivery, comfort, systemic effects and efficacy of dental local anaesthesia. Factors influencing the aspirating ability of dental local anaesthetic delivery systems are discussed. The effects of adrenaline in dental local anaesthetic solutions on plasma potassium levels and on the transplanted heart are described. The use of an infiltration technique as an alternative to the inferior alveolar nerve block in the mandible is discussed.