Background and objective: Deciduous teeth portray less pain sensitivity in comparison to permanent teeth. Conventional vitality tests depend on the stimulation of nerve fibers. Loss of sensory function due to trauma can result in negative responses. Unpleasant painful stimuli may lead to apprehensiveness and require behavior management in children. This study is a genuine attempt to compare pulp oxygen saturation levels of deciduous posterior teeth clinically or radiographically diagnosed as reversible pulpitis (RP), irreversible pulpitis (IRP), and pulpal necrosis (PN) with healthy teeth using a pulse oximeter with probes in preoperative and postoperative conditions. Methods: A total of 120 deciduous posterior teeth from participants aged 4–9 years were evaluated using random stratified sampling, divided into four groups with 30 teeth each based on clinical and radiological interpretation—group I: noncarious (NC) (control group); group II: RP; group III: IRP; group IV: PN. Teeth from children meeting the inclusion criteria were recorded and examined. The data obtained were sent for statistical analysis. Results: A significant difference in pulp oxygenation rates was observed between teeth with pulpal pathologies and healthy teeth in both preoperative and postoperative conditions. Interpretation and conclusion: Pulpal diseases cause a reduction in oxygen saturation of the pulp vasculature, thereby affecting the vitality of the tooth. The pulse oximeter used in the neonatal intensive care unit (ICU) was suitable for determining SpO₂% in children. Clinical significance: Pedodontists face challenges in making diagnoses because children may provide false-positive or false-negative responses to stimuli or questions. Pulse oximetry is a boon as it is highly efficient, can be used chairside, is completely atraumatic, and eco-friendly.