Reference values for pulp oxygen saturation as a diagnostic tool in endodontics: a systematic review and meta-analysis

OBJECTIVES: This systematic review aimed to identify mean oxygen saturation values (SpO(2)) using pulse oximetry in permanent maxillary anterior teeth. MATERIALS AND METHODS: The MEDLINE, Scientific Electronic Library Online, Cochrane Central Register of Controlled Trials, EMBASE, and Literatura Latino Americana em Ciências da Saúde electronic databases were searched. Combinations and variations of “oximetry” AND “dental pulp test” were used as search terms. Studies reporting means and standard deviations of SpO(2) values were included. Two reviewers independently extracted data following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Heterogeneity was assessed using the I(2) statistic, and all analyses were performed using R software. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and the Newcastle-Ottawa scale. RESULTS: Of the 251 studies identified, 19 met the eligibility criteria and were included (total sample, 4,541 teeth). In the meta-analysis, the mean SpO(2) values were 84.94% (95% confidence interval [CI], 84.85%–85.04%) for the central incisors, 89.29% (95% CI, 89.22%–89.35%) for the lateral incisors, and 89.20% (95% CI, 89.05%–89.34%) for the canines. The studies were predominantly low-quality due to the high risk of bias associated with the index test, unclear risk regarding patient selection, and concerns about outcome assessment. CONCLUSIONS: Although most studies were low-quality, the oxygen saturation levels in normal pulp could be established (minimum saturation, 77.52%). Despite the risk of bias of the included studies, the reference values reported herein are clinically relevant for assessments of changes in pulp status. TRIAL REGISTRATION: International Prospective Register of Systematic Reviews Identifier: CRD42018085598