How standard deviation contributes to the validity of a LDF signal: a cohort study of 8 years of dental trauma.

The aim of this cohort study was to document the potential of laser Doppler flowmetry (LDF) for diagnosing tooth vitality in traumatized teeth in a population of 88 referred patients with dental trauma over a period of 8 years (2011-2018). The main reason to refer was tooth discoloration (26%), and the main trauma cause was a traffic injury (35%). Taking into account that referral for LDF is best given within the week after trauma, 66% of referrals were overdue. In 73% of cases, root canal treatment could be avoided, and in 65%, the presence of a fixed orthodontic retainer showed beneficial for pulp recovery. Data of 394 teeth were collected and submitted to multilevel modelling statistics. As a general conclusion, both LDF perfusion and concentration values proved to be highly reliable in the appreciation of tooth vitality. The difference of variability of standard deviation and range of LDF measurements involving intra-subject control teeth showed statistically significant in discriminating between vital and non-vital pulps. In non-vital teeth, the diagnostic combination of LDF, sensibility tests and peri-apical X-ray is advised.