Effect of At-Home Bleaching on Oxygen Saturation Levels in the Dental Pulp of Maxillary Central Incisors

Pulse oximetry as a dental pulp test: A scoping review to identify barriers hindering the use of oximeters in clinical practice

Background and Objective

Although medical pulse oximeters are considered effective for endodontic diagnoses, the method remains uncommon in current dental practice. The aim of the present scoping review was to investigate clinical factors that exert a negative impact on the use of pulse oximeters in dental practice.

Methods

This study followed the PRISMA-ScR guidelines and the protocol was prospectively registered in the Open Science Framework (https://doi.org/10.17605/OSF.IO/3GQCE). A comprehensive search of the MEDLINE (via PubMed), Cochrane Library, and Web of Science databases was performed in December 2022 for articles published in English or Spanish. All types of clinical studies were included, except comments, letters to the editor, and abstracts. Two independent investigators analyzed 45 full-text articles. Data extraction included general characteristics, oxygen saturation levels, and limiting factors/barriers to the use of oximeters as pulp testers.

Results

The search of the databases yielded 1,300 records and 38 were included (quantitative data extraction was performed for 35 and three articles were systematic reviews). Publications were highest in number between 2016 and 2017, with an evident reduction occurring after 2021. The oxygen saturation level for sound/vital maxillary anterior teeth was 84.99% (overall mean). The main limiting factors/barriers were i) the difficulty in maintaining the two light-emitting diodes parallel during pulp tests, ii) infrared light diffraction by enamel/dentin/gingiva, and iii) the diversity of patient ages in studies.

Conclusion

This scoping review encountered noteworthy findings associated with the impracticability of using medical pulse oximeters as dental pulp testers. The recent decrease in the frequency of published studies compared to approximately seven years ago may imply a negative trend in the use of the method.

Evaluation of the Pulp Oxygen Saturation Reading after Tooth Bleaching: A Randomized Clinical Trial

Objectives

The purpose of this clinical trial was to evaluate the influence of in-office dental bleaching on the pulp oxygen saturation (SpO₂p) reading. Material and Methods. SpO₂p was measured using a pulse oximeter in 112 upper and lower anterior teeth (canines and incisors) of patients submitted to bleaching. Whitegold Office 35% (WGO) (upper and lower left hemiarch) and Whiteness HP Auto Mixx 35% (WHP) (upper and lower right hemiarch) bleaching agents were used. SpO₂ measurements (teeth and index finger) were taken before and after each of the three application sessions of the agents. In the 4^th session, in which no bleaching gel was used, only SpO₂ was measured. Before and after the bleaching sessions, a colorimetric device performed the teeth color reading. The waiting time between sessions was 7 days. Data were analyzed by the Friedman, Kruskal–Wallis, and Mann–Whitney U tests (α = 0.05). Color change (ΔE) data were correlated (Spearman's Rho test) with the SpO₂p levels.

Results

Neither of the two bleaching agents showed significant differences between the readings when evaluated individually (WGO, P=0.780, and WHP, P=0.494). When taken together, the results showed significant difference between the readings performed, with higher median values after bleaching sessions: before (97.3) and after (98.6) 1^st session; before (98.3) and after (98.3) 2^nd session; before (98.3) and after (99.0) 3^rd session; and after 1 week (98.3). The dental groups formed by maxillary lateral incisors (P=0.012) and mandibular incisors (P < 0.001) showed a significant difference. Spearman's Rho test showed a nonsignificant and weak correlation between ΔE and SpO₂p in most comparisons.

Conclusions

The in-office dental bleaching influenced the SpO₂p reading, regardless of the dental group evaluated or the bleaching agent used. Clinical Relevance. This study provides information about the influence of in-office tooth whitening on the pulp SpO₂p levels. The observation of pulp vitality during and after the use of bleaching agents is important for the follow-up of patients undergoing tooth whitening. The use of a pulse oximeter may be a viable and painless alternative to perform this monitoring. The clinical trial was registered with the Brazilian Registry of Clinical Trials (ReBEC; registration number: https://clinicaltrials.gov/ct2/show/RBR-68xbth).

Pulse Oximetry as a Diagnostic Tool to Determine Pulp Vitality: A Systematic Review

Pulse oximetry (PO) can be used as a technique to assess vascularization. Although it is commonly used in the field of medicine, it still has limited use in dentistry. The aim of this study is to evaluate, by means of a systematic review, if pulse oximetry is a viable and effective system to determine pulp vitality and assess the clinical criteria for its use. A literature search was performed in Medline, Scopus, Embase, and Web of Science databases. Clinical studies using pulse oximetry as a tool to determine pulp vitality in permanent teeth were eligible. Quality assessment of the included studies was performed following the Quality Assessment for Diagnostic Accuracy Studies (QUADAS-2) guidelines. A total of 24 articles were included in the review. The subjective test most compared to PO was the cold test. PO has shown a good sensibility and specificity, and it has been used in different clinical situations. Pulse oximetry has a high potential as a tool for the diagnosis of pulp vitality. However, the absence of a specific pulse oximeter for a dental practice, among other limitations, added to the lack of evidence on how different systemic and oral pathologies may affect the pulp’s oxygen saturation levels, which hinders its clinical use.

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 (SpO₂) 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 SpO₂ 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 I² 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 SpO₂ 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