A new protocol to evaluate the effect of topical anesthesia

Area of Science:

• Oral medicine
• Pain research
• Clinical pharmacology

Background:

• Assessing orofacial pain requires reliable and valid sensory testing methods.
• Quantitative sensory testing (QST) protocols are used to evaluate pain perception.
• Needle penetration sensitivity (NPS) is a specific measure for evaluating pain response to needle insertion.

Purpose of the Study:

• To evaluate the reliability, validity, and sensitivity to change of punctate pain thresholds and self-reported pain on needle penetration.
• To assess the correlation between different pain sensitivity measures.
• To determine if lidocaine gel affects pain sensitivity in healthy individuals.

Main Methods:

• A double-blind, placebo-controlled, randomized cross-over study was conducted on 29 female subjects without orofacial pain.
• Standardized quantitative sensory testing (QST) including mechanical pain threshold (MPT), pressure pain threshold (PPT), mechanical pain sensitivity (MPS), and needle penetration sensitivity (NPS) was performed.
• Lidocaine hydrochloride 2% or placebo gel was applied to the mucobuccal fold before sensory testing.

Main Results:

• All measures demonstrated good to excellent test-retest reliability (Intraclass Correlation Coefficients ranging from 0.69 to 0.86).
• A high correlation was observed between NPS and MPS (r = 0.84; P < .001).
• No significant changes in sensory measures were detected after application of lidocaine or placebo gel.

Conclusions:

• Quantitative sensory testing measures, including NPS and MPS, exhibit good reliability and validity for assessing oral mucosa sensitivity.
• Current QST methods did not detect sensitivity changes with topical lidocaine or placebo in healthy subjects.
• Further research is needed to explore the clinical utility of these measures in pain conditions.