# Pulse oximetry as a Diagnostic Tool to Determine Pulp Vitality: A Systematic Review
## 3 Results
### Study Results  
All authors expressed their results as percentages of oxygen saturation levels, except for [PERSON] et al. (2017) [23], who measured the pulpal oxygen saturation of maxillary amines after alveolar cleft bone grafting in mmHg, using the healthy contralateral canine as the control group. They reported 85.04 mmHg in the affected canine, and 87.78 mmHg in the healthy canine when using a Criticcare 504 pulse oximeter (Criticare, Waukesha, WI, USA). A total of eight studies reported pulp vitality test outcomes as SpO\({}_{2}\) levels by type of tooth [11; 17; 18; 27; 28; 31; 32]. Moreover, %SpO\({}_{2}\) values reported by the previously mentioned studies, categorized by tooth type, along with their sample numbers, are presented in Table 4. All studies found PO reliable regardless of the tooth type, although studies that compared maxillary and mandibular teeth generally found higher levels of SpO\({}_{2}\) in mandibular teeth. Pulse oximetry was also assessed as a tool for the diagnosis of pulp vitality at different stages of pulp inflammation, i.e., reversible pulpitis, irreversible pulpitis, necrotic pulp. [PERSON] et al. (2012) [26] and [PERSON] et al. (2017) [15] compared PO to thermal tests; [PERSON] et al. (2016) [4] compared it only to the cold test, and [PERSON] and [PERSON] (2017) [30] compared PO to the EPT. In all cases, the studies measured SpO\({}_{2}\) in different pulpar inflammatory states, producing statistically significant results and consequently concluding that PO was a valid diagnostic tool. These results, categorized by pulp status, are summarized in Table 5.  
The same was observed in studies evaluating the effectiveness of PO to determine pulp vitality after trauma [2; 4; 10]. In all of the studies, after assessing the changes in SPO\({}_{2}\) in traumatized teeth at different time periods, it was concluded that PO was a viable diagnostic tool in these cases. Two studies investigated the effect of head and neck radiotherapy (RT) on SPO\({}_{2}\) using pulse oximetry [21; 22]. While [PERSON] et al. (2016) [22] studied the levels of %SpO\({}_{2}\) by type of teeth, in the study of 2011 [21], they calculated the SpO\({}_{2}\) levels at different stages of radiotherapy (RT). Therefore, at the first time point (before the RT), the mean percentage of SpO\({}_{2}\) of the assessed teeth was 93%, at the second time point (beginning of RT with radiation doses between 30 Gy and 35 Gy) 83%, at the third time point (end of RT with radiation doses between 60 Gy and 70 Gy) 77%, and at the fourth time point (four months \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Author** & **Teeth** & **Sample** & **Age** & **Patients** & **Test** & **Measure** & **Pulse oximeter** \\ \hline \multirow{6}{*}{[PERSON]. [PERSON] (2018) [27]} & \multirow{6}{*}{UCI} & Study: 68 & & & & & Portable pediatric pulse \\  & & PCG: - & 19–36 & 41 w & PO & & & & \\  & & NCG: 10 & & 27 m & CT & & & \\  & & & & & & & & \\ \hline \multirow{6}{*}{[PERSON] (2020) [2]} & \multirow{6}{*}{I} & Study: 37 & & & & & Monitor: Nellcor N-600 \\  & & & & & & & (Healthcare group LP, & \\  & & & & & & PO & & Pleasanton, CA, USA). \\ \cline{1-1}  & & & & & & CT & & Sensor: N3 oxy sensor \\ \cline{1-1}  & & & & & & HT & & (Healthcare group LP, \\ \cline{1-1}  & & & & & & & & \\ \cline{1-1}  & & & & & & & & & \\ \cline{1-1}  & & & & & & & & \\ \hline \end{tabular}  
* I: incisors; C: canines; P: premolars; M: molars; UCI: upper central incisors; ULI: upper lateral incisors; UC: upper cenines; LCI: lower central incisors; LLI: lower incisors; LC: lower cenines; UP: upper premolars; LP: lower molars; LM: lower molars; PO: pulse oximetry; CT: cold test; HT: heat test; EPT: electric pulp test; LDF: laser Doppler flowmetry; PCN: positive control group; NCG: negative control group; SpO\({}_{2}\): pulp oxygen saturation level; PPV: positive predictive value; NPV: negative predictive value; w: woman; m: men.  
\end{table} 
Table 3: _Cont._to five months after the beginning of cancer treatment) 84%.