Fear and anxiety related to the administration of local anaesthetic is a common reason for avoiding dental procedures. Topical anaesthesia may be used to reduce discomfort from local anaesthetics and a variety of agents and formulations are available.
The aim of this review was to determine whether the use of topical anaesthetics is effective in reducing pain during needle puncture and local anaesthetic infiltration when compared to a placebo.
Methods
The review protocol was registered on PROSPERO and searches were conducted in the Cochrane Library, Medline/PubMed, and Scopus databases. Parallel of cross-over randomised controlled trials (RCTs) comparing topical anaesthetic prior to injection v placebo or no topical agent using a valid pain instrument and published in English were included. Two reviewer independently selected studies with data being extracted by a single reviewer and checked by a second reviewer. Two reviewers assessed risk of bias using the Cochrane Collaboration Risk of Bias version 2 (RoB 2) tool. Meta-analyses were conducted with pain reported as standardised mean difference (SMD) with 95% confidence intervals (CI).
Results
- 22 RCTs involving a total of 1029 patients were included.
- Patients ages ranged from 5 – 72 years.
- topical anaesthetics used included 2% lidocaine, 2% lidocaine patch + 12.5 mg epinephrine, 5% lidocaine,
- 10% lidocaine, 20% lidocaine, 60% lidocaine, EMLA cream, 20% benzocaine, 1% ropivacaine, 2% ropivacaine, Gingicaine, and Legecain-solution
- Needle gauge was 25G, 27G, 30G, or 33G.
- 15 studies reported drying mucosa before applicant, one reported not drying the remainder did not specify.
- 9 RCTs reported on the perception of pain associated with anaesthetic infiltration.
- Meta-analysis (5 studies) showed no significant reduction in pain associated with anaesthetic infiltration with the use of topical anaesthetics., SMD= –0.85 (95%; –1.88 to 0.18)
- 7 studies reported a reduction in pain parameters during needle puncture compared to placebo.
- 14 studies contributed to the meta-analyses the findings for different regions and anaesthetic agents are shown in the table.
| Standardised mean difference (95%CI) | |||
| Anaesthetic | Maxilla vestibular area | Palatal region | Mandibular region |
| Lidocaine | -1.09 (-2.02 to -0.16) | -1.65 (4.15 to 0.86)* | -0.12 (-0.47 to 0.23)* |
| Benzocaine | -0.59 (-1.00 to -0.17) | -0.02 (-0.47 to 0.43)* | -3.09 (-3.90 to -2.27) |
| Ropivacaine | -0.67 (-1.12 to -0.22) | -0.31 (-0.75 to 0.13)* | N/A |
| EMLA | N/A | -1.00 (-1.38 to -0.61) | -0.97 (-1.63 to -0.10) |
| All agents | -0.81 (-1.23 to -0.39) | -0.84 (-1.42 to -0.26) | -1.07 (-2.25 to 0.10)* |
*Not significant
Conclusions
The authors concluded: –
the use of topical anaesthetics for pain relief with regard to needle puncture is effective when used in the maxilla. On the other hand, the same assessment for the mandible did not show statistically significant results in favour of topical anaesthetics.
Comments
Searches were conducted in 3 major databases although restricting inclusion to papers published in English may mean that some relevant studies may have been excluded. 22 RCTs were included with the reviewers assessing them all as being at low risk of bias although 2 were considered unclear in relation to randomisation and one in relation to allocation and all 22 were unclear in relation to selective reporting. A wide range of topical anaesthetic agents and formulations were tested, and statistically significant differences were seen during needle puncture with topical anaesthetic use in the maxilla and palate but not the mandible. While meta-analyses are presented for different areas of the mouth and for different types of anaesthetics the numbers of studies contributing to these analyses is small. No difference was seen will topical anaesthetic use for pain caused during maxillary infiltration. Because of the variations in sample size, participant ages, types of anaesthetic agent, needle gauges, application times and procedures the findings should be interpreted cautiously.
Links
Primary Paper
Maia FPA, Araujo Lemos CA, de Souza Andrade ES, de Morais SLD, do Egito Vasconcelos BC, Pellizzer EP. 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. Int J Oral Maxillofac Surg. 2021 Aug 11:S0901-5027(21)00229-0. doi: 10.1016/j.ijom.2021.06.005. Epub ahead of print. PMID: 34391592.
Other references
Dental Elf – 17th Feb 2021
Vibration devices: Do they reduce pain linked to dental injections in children?
Dental Elf – 2nd Mar 2020
Local anaesthetic for dental treatment: interventions to improve acceptance in children
