Threshold response to electric pulp testing in anterior teeth of patients with and without history of COVID-19: analytical cross-sectional study

Abstract

Objective: To compare the response threshold to the electric pulp test (EPT) in anterior teeth of adults with and without a history of COVID-19. Materials and methods: This was an observational, cross-sectional, analytical study conducted in 2024. A total of 89 adults were evaluated (48 women, 41 men): 49 without a history of COVID-19 and 40 with confirmed COVID-19 recorded in the clinical history. No uniform interval was established between infection and clinical evaluation. In maxillary and mandibular incisors and canines, a standardized EPT protocol was applied based on previous recommendations for pulp sensibility testing: electrode placement on the middle third of the buccal surface, use of a conducting medium, dry field isolation, two measurements per tooth, and calculation of the average value. The primary variable was the individual mean EPT response latency, and the exposure variable was history of COVID-19 (yes/no). Descriptive statistics, Student’s t-test for independent samples, and chi-square test were used, with 95% confidence intervals. The primary analysis accounted for the tooth-subject nesting structure using a linear mixed model (random intercept for subject; fixed effects for COVID-19, tooth type, age, and sex). Results: The response threshold had a mean of 25.29 s (SD = 23.42) in the group without COVID-19 and 42.29 s (SD = 28.58) in the group with COVID-19, with a mean difference of 17.00 s (95% CI: 5.80 to 28.20; p = 0.003). Descriptively, the group with a history of COVID-19 showed higher latencies in all anterior teeth evaluated. In the adjusted linear mixed model, history of COVID-19 remained significantly associated with greater EPT response latency (adjusted β = 15.9 s; p = 0.005). Conclusions: In this clinical sample, a history of COVID-19 was associated with an increased EPT response threshold in anterior teeth. These findings should be interpreted as preliminary and confirmed in longitudinal studies incorporating disease severity, time since infection, and potential confounders.