Assessment of Pulpal Oxygen Saturation in Healthy and Diseased Primary Teeth Using a Customized Pulse Oximeter Holder in Children Aged Four to Nine Years: A Cross-Sectional Study.

Introduction Accurate assessment of pulp vitality is essential for diagnosis and treatment planning in pediatric dentistry. Conventional pulp sensibility tests, including thermal and electric pulp testing, assess neural response rather than pulpal vascularity and often demonstrate limited reliability in primary teeth. Pulse oximetry provides a non-invasive, objective assessment of pulpal oxygen saturation; however, evidence regarding its use in primary dentition remains limited. This study evaluated pulpal oxygen saturation in healthy and diseased primary teeth using a customized pulse oximeter holder and established reference values for different tooth types and pulpal conditions. Methods This descriptive cross-sectional study included 610 primary teeth from 271 children aged four to nine years, with multiple teeth included from some participants. Phase I comprised 530 healthy primary teeth, including maxillary and mandibular incisors, canines, first molars, and second molars. Phase II included 80 mandibular primary molars categorized as healthy pulp, reversible pulpitis, irreversible pulpitis, pulpal necrosis, and endodontically treated teeth (n = 16/group). A customized three-dimensional printed pulse oximeter holder was fabricated to ensure optimal adaptation and parallel alignment of the light-emitting diode (LED) and photodetector. Pulpal diagnosis was established using clinical history, clinical and radiographic examination, cold testing, electric pulp testing, and bleeding on access cavity preparation when indicated. Pulpal oxygen saturation was recorded three times for each tooth, and the mean value was analyzed. Statistical significance was set at p < 0.05. Results Pulpal oxygen saturation differed significantly among primary tooth types in both arches (p < 0.001). Maxillary central incisors exhibited the highest mean oxygen saturation (89.29 ± 2.20%), whereas mandibular second molars demonstrated the lowest values among healthy teeth (84.18 ± 2.81%). Anterior teeth showed significantly higher oxygen saturation than posterior teeth in both arches (p < 0.001). In Phase II, mean pulpal oxygen saturation progressively declined from healthy pulp (83.44 ± 2.56%) to reversible pulpitis (80.25 ± 2.70%), irreversible pulpitis (70.50 ± 3.98%), pulpal necrosis (11.13 ± 15.34%), and endodontically treated teeth (0.00%) (p < 0.001). Healthy pulp and reversible pulpitis demonstrated overlapping oxygen saturation values, whereas advanced pulpal disease showed significantly lower values. Finger oxygen saturation remained stable across all groups. Conclusions Pulpal oxygen saturation in primary teeth varied according to tooth type, dental arch, anatomical region, and pulpal status, demonstrating a progressive decline with advancing pulpal pathology. The customized pulse oximeter holder enabled consistent and reproducible measurements across different primary teeth. Pulse oximetry appears to be a promising objective and non-invasive adjunct to conventional pulp sensibility tests for assessing pulp vitality in children. However, further longitudinal studies incorporating appropriate statistical methods to account for clustered observations and larger study populations are needed to validate tooth-specific reference values and establish its routine clinical applicability.