Pulp blood flow velocity analysis using ultrasound doppler flowmetry in anterior teeth and intra- and inter-examiner reliability

Abstract

1. Objectives Clinical diagnosis of pulpal status is difficult and occasionally confusing. A thermal (cold or hot) test and electric pulp test (EPT) are commonly used to evaluate pulpal nerve sensibility. However, these tests say nothing about pulp blood flow, which means true pulp vitality. The aims of this study were as follows: 1) to measure pulp blood flow velocities of clinically normal maxillary anterior teeth of healthy adults using ultrasound Doppler flowmetry (UDF), 2) and to evaluate intra- and inter-examiner reliability of UDF.

2. Materials and Methods 1) Part 1: Measurement of pulp blood flow velocities in maxillary anterior teeth A total of 359 anterior teeth from 62 patients (mean age, 29.8 years; range, 22 to 52 years; 26 females and 36 males) were included. The data were collected according to tooth type (three groups: central incisors, lateral incisors, and canines). An MM-D-K (Minimax, Moscow, Russia) ultrasound Doppler imaging instrument with a 20-MHz probe was used to measure pulp blood flow velocity. Differences between the tooth types were analysed with one-way ANOVA and a Bonferroni correction at the 95% confidence level. 2) Part 2: Intra-examiner and inter-examiner reliability A total of 222 anterior teeth from 37 patients (mean age, 25.4 years; range 21 to 32 years; 13 females and 24 males) were included. An MM-D-K (Minimax, Moscow, Russia) ultrasound Doppler imaging instrument with a 20-MHz probe was used to measure pulp blood flow velocity. For the intra-examiner reliability, one examiner measured the patients at about 1 week intervals for three weeks. For the inter-examiner reliability, the blood flows of patients were measured by five examiners using the UDF. Data were analysed with a repeated measure ANOVA (RM_ANOVA) and Tukey as a post hoc test at the 95% confidence level. Intraclass correlation coefficients (ICCs) were calculated from the data for intra- and inter-examiner reliability.

3. Results 1) Part 1: Measurement of pulp blood flow velocities in maxillary anterior teeth The mean average linear velocities during the systolic period (Vams) of the central incisors, lateral incisors, and canines were 0.58 cm/s, 0.58 cm/s, and 0.52 cm/s, respectively. There were no significant differences in the mean Vams between the tooth types (P >0.05). 2) Part 2: Intra-examiner and inter-examiner reliability Intra-examiner reliability: There were no significant differences in the Vam measurements among three time points (P>0.05), and ICC was 0.56. Inter-examiner reliability: There were significant differences in the average linear velocities during the systolic period (Vam) measurements among the five examiners (P=0.044), and ICC was 0.41.

4. Conclusions Within the limitations of this study, the pulp blood flow velocities of clinically normal, maxillary anterior teeth of healthy adults were 0.56 ± 0.46 cm/s. There were no significant differences in mean blood flow velocities between maxillary central incisors, lateral incisors, and canines. Intra-examiner consistency demonstrated no significant differences among the measured time points and moderate to low reproducibility. Inter-examiner consistency demonstrated statistically significant differences among examiners and a low reliability. The methods which can reduce the variations between different examiners should be investigated in the near future.

Key words: pulp blood flow velocity; pulp vitality; ultrasound Doppler; intra-examiner reliability; inter-examiner reliability