Effectiveness of 20% Benzocaine as a Topical Anesthetic for Intraoral Injections

In: Anesthesia

29 Oct 2009


Fear of the needle has been reported as one of the major causes of apprehension in dental patients. Patients have reported that the feeling of the needle being inserted into the tissue is a chief source of anxiety. Empirically, it makes sense to attempt to reduce this source of anxiety and assure the patient that everything possible is being done to make their appointment comfortable. Topical anesthesia has been advocated for the reduction of a patient’s anxiety and pain.

The pharmacological and psychological effects of topical anesthetics have been studied. However, the results have varied. Rosivack et al, Hersch et al, and Hutchins et al have reported topical anesthetic to be effective in reducing the pain of needle penetration. Conversely, Gill and Orr, Keller, and Martin et al failed to show any differences in effectiveness between a topical anesthetic and placebo in reducing needle insertion pain. Martin et al also showed that topical anesthesia reduced the patients’ anticipation of injection pain, but did not reduce reported pain. Kincheloe et al reported that patients with high expectations of pain experienced more pain than those with low expectations, and that topical anesthesia had no effect on the pain experienced. tamsulosin 0.4 mg

Nakanishi et al reported that the effectiveness of topical anesthesia may be related to the location of the injection. They found that topical anesthesia reduced the pain of needle insertion in the mandibular mucobuc-cal fold adjacent to the canine, but failed to reduce pain in the pterygotemporal depression (lateral to the pterygomandibular raphe) where an inferior alveolar nerve block is given. Hersch et al found that lidocaine patches were more successful in reducing the pain of needle insertion in the mandibular premolar buccal fold as compared with the maxillary premolar buccal mucosa.

The purpose of this study was to compare the effectiveness of a topical anesthetic (20% benzocaine) in reducing the pain of needle insertion during maxillary posterior and anterior infiltration injections and inferior alveolar nerve block injections. finasteride hair loss

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