Correlation between temporomandibular joint temporal component pneumatization and morphology: analysis by cone beam computed tomography

The aim of this study was to evaluate whether a correlation exists between temporal bone pneumatization and the morphology of the articular eminence and glenoid fossa. A sample of 100 cone beam computed tomography scans was used, for a total of 200 temporomandibular joints (TMJ). Paracoronal and parasagittal images of the TMJ were evaluated by two examiners. For all TMJ, pneumatization was classified in the mid-lateral direction using a score of 0 or 1, and in the anteroposterior direction using a score ranging from 0 to 3. The inclination and height of the articular eminence and the thickness of the roof of the glenoid fossa were obtained. Pneumatization was found in the mid-lateral direction in 83.5% of the cases and in the anteroposterior direction in 88%. The age of the patient and side did not influence the prevalence or degree of pneumatization (P=0.051-0.953), but female patients showed more pneumatization in the mid-lateral direction than male patients (P=0.014). The presence of pneumatization did not affect articular eminence and mandibular fossa morphology. It is concluded that the presence and extent of pneumatization of the TMJ temporal component does not affect its morphology. However, professionals should be aware of the high prevalence of pneumatization and take this into account when performing TMJ assessment.

Effect of delayed scanning on imaging and on the diagnostic accuracy of vertical root fractures in two photostimulable phosphor plates digital systems

AIM

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.

METHODOLOGY

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.

CONCLUSION

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.

Efficacy of lead foil for reducing doses in the head and neck: a simulation study using digital intraoral systems

OBJECTIVES

To assess the efficacy of lead foils in reducing the radiation dose received by different anatomical sites of the head and neck during periapical intraoral examinations performed with digital systems.

METHODS

Images were acquired through four different manners: phosphor plate (PSP; VistaScan(®) system; Dürr Dental GmbH, Bissingen, Germany) alone, PSP plus lead foil, complementary metal oxide semiconductor (CMOS; DIGORA(®) Toto, Soredex(®), Tuusula, Finland) alone and CMOS plus lead foil. Radiation dose was measured after a full-mouth periapical series (14 radiographs) using the long-cone paralleling technique. Lithium fluoride (LiF 100) thermoluminescent dosemeters were placed in an anthropomorphic phantom at points corresponding to the tongue, thyroid, crystalline lenses, parotid glands and maxillary sinuses.

RESULTS

Dosemeter readings demonstrated the efficacy of the addition of lead foil in the intraoral digital X-ray systems provided in reducing organ doses in the selected structures, approximately 32% in the PSP system and 59% in the CMOS system.

CONCLUSIONS

The use of lead foils associated with digital X-ray sensors is an effective alternative for the protection of different anatomical sites of the head and neck during full-mouth periapical series acquisition.

Comparison of digital systems and conventional dental film for the detection of approximal enamel caries

OBJECTIVES

The aims of this study were (1) to compare the accuracy of the detection of approximal enamel caries lesions using three intraoral storage phosphor plate digital systems and one conventional film-based radiographic system; and (2) to determine whether there is a correlation between the histological and radiographic measurements of enamel caries.

METHODS

160 approximal surfaces were radiographed under standardized conditions using three storage phosphor stimulable systems (DenOptix and Digora FMX with white and blue plates), and one film system (Insight film). 17 observers scored the images for the presence and depth of caries using a 4-point scale. The presence of caries was validated histologically (gold standard). Two-way analysis of variance was used to test the differences in sensitivity, specificity and overall accuracy (TP + TN). The data from the radiographic and histological measurements were statistically analysed by Spearman's rank correlation coefficient.

RESULTS

Two-way analysis of variance and the post hoc t-test demonstrated that Digora (white plate) had higher specificity and overall accuracy values than DenOptix (P = 0.021); there was no statistically significant difference among the other imaging modalities (P > 0.05). There was no significant correlation between the histological depth measurements and the radiographic measurements from Digora (blue plate) (P = 0.43), Digora (white plate) (P = 0.15), DenOptix (P = 0.17) and Insight film (P = 0.06).

CONCLUSIONS

The results suggest that (1) the performance of the three storage phosphor image plate systems was similar to that of the Insight film for detection of approximal enamel caries, and (2) the increase in histological depth of enamel caries was not significantly correlated with radiographic measurements.

What happens if you delay scanning Digora phosphor storage plates (PSPs) for up to 4 hours?

OBJECTIVES

To assess, both objectively and subjectively, the effects of different combinations of storage conditions and delaying scanning for up to 4 h on digital images captured using Digora phosphor storage plates (PSPs).

METHOD

Standardized images were obtained of an aluminium step wedge and dry mandible in acrylic using GE 1000 and phosphor storage plates (PSPs) from the Digora (Soredex) digital system. 12 plates were exposed and immediately scanned to produce the baseline gold standard. The plates were re-exposed and stored using three different storage combinations--(A) ambient temperature, (R) refrigeration and (S) low humidity, and then scanned after 10 min, 30 min, 1 h, 2 h, 3 h or 4 h. The objective analysis was carried out by pixel density measurements and the data analysed statistically using analysis of variance. Subjective analysis was carried out by three oral radiologists and the results analysed using the Mann Whitney U-test.

RESULTS

Objective analysis showed loss of pixel density after 4 h using all storage combinations. Subjectively, this loss of density was not evident.

CONCLUSION

There is a loss of image density at 4 h when using Digora PSPs which can not be detected clinically, but could compromise multisite research.

Analysis of digital images acquired using different phosphor storage plates (PSPs) subjected to varying reading times and storage conditions

OBJECTIVES

To assess, both objectively and subjectively, the effects of different combinations of storage conditions and varying delays in reading on digital images captured using phosphor storage plates (PSPs).

METHOD

Standardized images were obtained of an aluminium step wedge and a dry mandible in acrylic using GE 1000 and PSPs from the Digora (Soredex) and DenOptix (Gendex) digital systems. Twelve plates from each system were exposed and immediately scanned to produce the baseline gold standard. The plates were re-exposed and stored using three different storage combinations, (A) ambient temperature, (R) refrigeration and (S) low humidity, and then scanned after 6 h, 12 h, 18 h, 24 h, 48 h or 72 h. Objective analysis was carried out by pixel density measurements and the data were analysed statistically using analysis of variance. Subjective analysis was carried by three oral radiologists and the results were analysed using Mann-Whitney U-test.

RESULTS

For the DenOptix system there were no differences either objectively or subjectively in the images obtained from all the plates using different storage conditions and after varying time intervals. For Digora, objective analysis showed loss of pixel density after 6 h using all storage conditions. This loss of density was also evident subjectively after 6 h on plates stored under certain storage conditions.

CONCLUSION

Storage of DenOptix PSPs for up to 72 h in different conditions does not affect the quality of the digital images. However, there is a loss of image density within 6 h when using Digora PSPs, which may affect clinical image interpretation.

Fraudulent use of radiographic images

The aim of this study was to evaluate the ability of trained observers to identify altered radiographic images after modifications using an image-editing software. Based on implantology in 10 radiographs, eight panoramic and one linear tomograph were modified while one tomograph was untouched. Implants were placed or removed and bone levels were altered, and seventy dentists were invited to identify these alterations. The results showed that the percentage of the correct answers was 12.5% or 2 identifications per examiner. The rate of false positives in relation to correct answers was at a level of 6:1. We concluded that the professionals have difficulty in identifying altered radiographs after using an image-editing software and that the seriousness of this situation demands that dentists be warned of the dangers of the use and abuse of this technology.

Clinical study of the sensitivity and dynamic range of three digital systems, E-speed film and digitized film

The objective of the present study was to clinically evaluate the sensitivity and dynamic range of three digital systems (Sens-A-Ray, CDR, Digora), digitized film and E-speed film. Five objects were submitted to three different kilovoltages and seven exposure times. In order to evaluate the relationship between exposure time and dosage, measurements were made in a dental x-ray unit with an ion chamber, X-ray timer and kVp meter. For each system, 105 radiographs were taken, totalling 525 images, that were evaluated by six trained observers by means of scoring from 0 to 4. The scores attributed to the images for each of the systems were submitted to analysis of variance and Turkey's test. The results showed statistically significant differences (p < 0.01) with the storage phosphor system producing the wider dynamic range, followed by the digitized film. The CDR system showed the greater sensitivity, followed by the Digora system.

[Clinical and comparative study of the image quality of 3 digital radiographic systems, E-speed film and digitalized film]]

The aim of this study was to evaluate, subjectively, the image quality of two CCD digital systems, a digital storage phosphor system, a digitized film and an E-speed film. Five objects were radiographed with 50, 60 and 70 kVp, with exposure times of 0.08, 0.13, 0.2, 0.4 and 0.8 s. In order to maximize the fidelity of the results, the dental X-ray unit employed was submitted to an evaluation so that the relation between exposure time and dose could be established. A good reproducibility was obtained. Six evaluators analyzed 375 images, using a scoring scale which ranged from 0 to 4. The results revealed different responses, indicating that the storage phosphor system had the best performance, in the various exposures employed. However, it was possible to conclude that all systems studied, except for the Sens-A-Ray, can offer images in ideal conditions for the diagnosis, as long as their latitudes are respected.

Comparative study of two digital radiographic storage phosphor systems

The objective of this study was to evaluate the image quality and dynamic range of two digital radiographic storage phosphor systems: Digora (Soredex, Finland) and DenOptix (Gendex, USA). Four objects were analyzed and eight exposure times employed, totaling 64 images that were analyzed by 5 examiners using a scale from 1 to 4 to classify the images. The scores were submitted to analysis of variance and the results showed statistical differences among the averages attributed to the systems, to the exposition times and to the objects (p 0.01 Pound). Digora presented a larger dynamic range and, in general, a better image quality. Although these 2 systems present the same photon detector, they present different results in relation to the evaluated items.

[Assessment of 3 radiographic methods (conventional periapical, digital periapical, and panoramic) ni the diagnosis of artificially produced periapical lesions]

This research was carried out in order to evaluate three radiographic methods--conventional periapical, digital periapical and panoramic--in the diagnosis of artificially produced periapical lesions. For this purpose, 5 mandibles, with lesions produced by means of spherical drills of different sizes, were used. The research was divided into five distinct phases, as follows: phase Z (initial)--characterized by the absence of lesion; phase R--lesion produced with a number 6 drill; phase J--lesion produced with a number 8 drill; phase D--lesion produced with a number 10 drill; and phase H--lesion reaching the vestibular cortex. The lesions were produced in quadrants. Radiographs were made after each phase and analyzed by 4 experts in radiology. For the digital system there was statistically significant difference in phase R (in the region of incisors) and in phase H (in the region of premolars). In the region of molars there was statistically significant difference in phase D for panoramic radiography. It must be pointed out that panoramic radiography produced the less effective results in phase H.