Evaluation of Cold and Electric Pulp Tests for Assessing the Success of Inferior Alveolar Nerve Block for Mandibular
Farzaneh Afkhami1, Sholeh Ghabraei2, Nasim Hashemi2
1School of Dentistry, The University of Queensland, Brisbane, Australia; Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
Introduction:
Fear of dentistry, often due to past painful experiences, is a significant barrier preventing patients from visiting dentists. Achieving effective pain control, especially during root canal treatments, is crucial. However, inferior alveolar nerve blocks (IANBs) have a low success rate, influenced by factors such as anxiety, anatomical variations, and technique limitations, leading to anesthesia failure. Although numerous studies have examined the cold test and electric pulp test (EPT) in assessing the success of local anesthesia, no standardized method has been established. This study evaluated the effectiveness of EPT and cold tests in assessing the depth of anesthesia in patients with symptomatic irreversible pulpitis in the mandibular first molar teeth.
Methods:
A cross-sectional study was conducted on 50 patients with symptomatic irreversible pulpitis who met the inclusion criteria and exhibited lip numbness. Following the administration of the IANBs and confirmation of lip numbness, cold tests and EPT were performed on all patients. Subsequently, the preparation of the access cavity (gold standard test) was initiated, and patients' responses during cavity preparation were recorded as either "presence of pain or discomfort" or "absence of pain or discomfort," indicating IANB failure and success, respectively. Sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), positive and negative likelihood ratios, and accuracy (AC) with 95% confidence intervals were calculated for each test separately as well as for sequential testing.
Results:
IANB failure was determined in 56% of the patients. A comparative analysis of diagnostic tests (cold test and EPT) showed no significant difference in SN, NPV, and AC; however, the cold test had higher SP, PPV, and positive likelihood ratio. Combining cold test and EPT evaluations improved SN, NPV, PPV, and negative likelihood ratio, but SP and AC were similar to EPT alone. No correlation was found between IANB success and patient age, sex, or initial pain.
Conclusions:
Despite evidence of lip numbness, a significant number of IANBs failed in cases of painful pulpitis. A positive result from the cold test strongly indicated anesthesia failure. The findings of the current study suggested that when the cold test yielded a negative result, further evaluation with EPT was necessary to confirm anesthetic success and ensure complete pain control.
