The diagnostic accuracy of laser Doppler flowmetry in assessing pulp blood flow in permanent teeth: A systematic review.

BACKGROUND/AIM: Pulp necrosis is a frequent complication following dental trauma. The diagnosis of the state of the dental pulp can be challenging as most commonly used diagnostic tools are subjective and rely on a response from the patient, potentially making their use unreliable, especially in the child population. The aim of the study was to systematically review the evidence on the use of laser Doppler flowmetry in the assessment of the pulp status of permanent teeth compared to other sensibility and/or vitality tests. METHODS: A systematic literature search, using MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, www.clinicaltrials.gov and www.controlled-trials.com, in addition to citation and manual reference list searches, was conducted up to 15th January 2018. A risk of bias assessment was performed using the quality assessment for diagnostic accuracy studies tool (QUADAS-2) with all steps performed independently by two reviewers. RESULTS: Four studies with a high risk of bias were included in the final analysis. Laser Doppler flowmetry was reported to be more accurate in differentiating between teeth with normal pulps and pulp necrosis with a sensitivity of (81.8%-100%) and specificity of 100% in comparison to other vitality tests such as pulp oximetry (sensitivity = 81.3%, specificity = 94.9%) and sensibility tests such as electric pulp testing (sensitivity = 63.3%-91.5%, specificity = 88%-100%). CONCLUSION: Despite the higher reported sensitivity and specificity of laser Doppler flowmetry in assessing pulp blood flow, these data are based on studies with a high level of bias and serious shortfalls in study designs. More research is needed to study the effect of different laser Doppler flowmetry's parameters on its diagnostic accuracy and the true cut-off ratios over which a tooth could be diagnosed as having a normal pulp.

A Diagnostic Accuracy Study of Laser Doppler Flowmetry for the Assessment of Pulpal Status in Children's Permanent Incisor Teeth.

INTRODUCTION: The aim of this study was to assess whether laser Doppler flowmetry is more accurate than the conventional pulp sensibility tests (electric pulp test and ethyl chloride) in assessing the pulpal status of permanent anterior teeth in children and to identify the laser Doppler flowmetry's Flux cut-off threshold. METHODS: A cross-sectional diagnostic accuracy study with randomization was performed and included 74 participants (8- to 16-year-old children). Participants had 1 maxillary central or lateral incisor with either a completed root canal treatment or an extirpated pulp and a contralateral tooth with vital pulp. Outcome measures included the sensitivity, specificity, and predictive values as well as the repeatability of all tests. RESULTS: A significant difference between the Flux values for teeth with vital and non-vital pulps was found. The cut-off ratio for laser Doppler flowmetry was 0.6, yielding a sensitivity of 53% and a specificity of 33%, which were lower than the values of the electric pulp test (sensitivity = 83.8%-94.6% and specificity = 89.2%-97.6%) and ethyl chloride (sensitivity = 81.1%-91.9% and specificity = 73%-81.1%). The repeatability of laser Doppler flowmetry, electric pulp testing, and ethyl chloride were 0.85, 0.86, and 0.81, respectively. CONCLUSIONS: Laser Doppler flowmetry was unable to differentiate between teeth with vital and non-vital pulps. The results of this study showed that there was a high probability for false results. Further development of laser Doppler flowmetry in assessing pulpal blood flow would be required before it could be recommended for clinical use, especially in children.