Diagnosis of approximal caries after delayed scanning of photostimulable phosphor plates

Statement of the Problem: Considering the high diagnostic accuracy and wide dynamic range of photostimulable phosphor plates [PSPs], they can be a good alternative for radiographic films

Purpose: This study was aimed to assess the effects of delay in scanning PSPs on the diagnostic accuracy of detection of approximal caries

Materials and Method: Radiographs from fifty-two extracted molar and premolar teeth were radiographed using DIGORA PSP [Soredex Corporation, Helsinki, Finland]

The teeth were either intact or with non-cavitated approximal caries. The plates were scanned immediately [time zero] and at 10 min, 30 min, 60 min and 120 min after exposure. Sixty-five images were obtained and evaluated for presence or absence of approximal caries by two oral and maxillofacial radiologists and 2 restorative specialists. The diagnostic accuracy of approximal caries detection was measured using a 5-point rating scale. Definite presence of caries was confirmed using a stereomicroscope. Analysis of caries detection data was performed by calculating sensitivity and specificity using repeated measures with ANOVA

Results: Significant differences were found in complete negative predictive value, absolute negative predictive value and complete dentine sensitivity value between different scan times [p< 0.05]

These values were significantly different at 10 min, 60 min and 120 min [p< 0.05]

However, immediate scan and 30 min delay were not significantly different [p> 0.05]

The accuracy of approximal caries detection at 120 min was less than at 60 min and at 60 min was less than at 30 min. Conclusion: In order to detect approximal caries more accurately, DIGORA PSPs should be scanned within 30 min after exposure

Evaluation of the relationship between relative signal intensity of magnetic resonance images of retrodiscal tissue and lateral pterygoid muscle and magnetic resonance imaging findings

Disc displacement is the most common temporomandibular joint disorder and magnetic resonance imaging [MRI] is the gold standard in its diagnosis. This disorder can lead to changes in signal intensity of magnetic resonance [MR]. The purpose of this study was evaluation of correlation between relative signal intensity of MR images of retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle with type of anterior disk displacement and condylar head flattening in patients with temporomandibular disorder [TMD]. In this retrospective study, 31 MR images of patients who had anterior disc displacement were evaluated. After relative signal intensity measurement for retrodiscal tissue, superior and inferior head of lateral pterygoid muscle, the correlation between relative signal intensity and type of anterior disc displacement was evaluated with repeated measure ANOVA test. In each of these 3 areas, t-test was used to compare the groups with and without condylar head flattening. The correlation between relative signal intensity of MR images and type of anterior disc displacement in retrodiscal tissue, superior and inferior head of lateral pterygoid muscle was not significant. There was also no statistically significant correlation between relative signal intensity of MR images and flattening of condylar head in retrodiscal tissue, superior and inferior head of lateral pterygoid muscle [P>0.05]. According to findings of this study, relative signal intensity of MR images in retrodiscal tissue, superior and inferior head of ptrygoid muscle is not a good predictor for type of anterior disc displacement and flattening of condylar head. It seems that this cannot be used as a diagnostic marker for TMD progression