Effect of delayed scanning on imaging and on the diagnostic accuracy of vertical root fractures in two photostimulable phosphor plates digital systems.
OBJECTIVE
To evaluate the influence of delayed scanning on images obtained with two PSPs digital systems and on the diagnostic accuracy of vertical root fracture (VRF) by means of objective and subjective analyses.


METHODS
Forty single-rooted human teeth were divided into two groups, one without VRFs and another with VRFs induced by a universal testing machine. Two digital systems (VistaScan(®) and Express(®) ) were used to radiograph all teeth, and the resulting plates were scanned at four time-points: T0-immediately, T1-30 min, T2-2 h and T3-4 h after exposure. An aluminium (Al) wedge was used to evaluate the change in mean grey values as each scan was delayed. Three observers screened all images for VRFs, and one-fourth of the sample was revaluated after thirty days. Areas under the receiver operating characteristic (ROC) curve, sensitivity, specificity and accuracy values were compared by anova.


RESULTS
Intra- and interobserver agreement ranged from moderate to substantial and fair to moderate, respectively. There was no significant difference amongst scan delays with regard to sensitivity, specificity and accuracy; however, there were significant differences in the area under the ROC curve, with the 4-h delayed scan being associated with lower values compared to the others (P = 0.019). As for objective analysis, there was a significant difference amongst all different scanning time-points for the two systems (P = 0.001), except between the 30-min and 2-h delayed scans in the VistaScan(®) system.


CONCLUSIONS
Whilst delayed scanning caused changes to the density of images acquired with the systems studied, it did not seem to interfere with VRF diagnosis except when scanning was delayed for 4 h, which should therefore be avoided.
Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil. arnhelena@gmail.com.
H A R
HA
Nascimento
Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil.
M A P G
MA
Visconti
Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil.
L M
LM
Ferreira
Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil.
M A
MA
Suarez
Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil.
F
F
Haiter Neto
Division of Oral Radiology, Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, São Paulo, Brazil.
D Q
DQ
Freitas
D006801:Humans; D012372:ROC Curve; D019252:Radiography, Dental, Digital; D012680:Sensitivity and Specificity; D013997:Time Factors; D014082:Tooth Fractures / Q000000981:diagnostic imaging*; D014092:Tooth Root / Q000000981:diagnostic imaging*
digital images; radiography; storage phosphor plates; vertical root fracture