Intraoral Receptors Research Articles

Comparing the Diagnostic Accuracy of Two Different Resolutions of Radiographs Captured with PSP Digital Intraoral Receptors in Detection of Secondary Caries (In Vitro)

Comparing the Diagnostic Accuracy of Two Different Resolutions of Radiographs Captured with PSP Digital Intraoral Receptors in Detection of Secondary Caries (In Vitro)

Comparison of images from digital intraoral receptors and cone beam computed tomography scanning for detection of voids in root canal fillings: an in vitro study using micro-computed tomography as validation

To compare the diagnostic value of six intraoral digital receptors and a cone beam computed tomography scanning system for detection of voids in root fillings. Sixty-seven root-filled roots with oval and ribbon-shaped canals were included. Three standardized radiographic examinations were performed for each root with six intraoral digital receptors. Further, the roots were examined using CBCT. Four observers measured the extension of voids in all images. The true extension of voids was recorded in cross-sectional images from micro-computed tomography scans (micro-CT). The proportion of voids observed in the radiographic image validated against micro-CT was calculated for each system. All intraoral receptors underestimated the extension of voids, and few false positives were recorded. CBCT resulted in a higher proportion of correctly observed voids, but with several false-positive recordings. The diagnostic value differed little among the six intraoral systems. CBCT overestimated in many cases the proportion of voids in root fillings.

Detection of cavitated approximal surfaces using cone beam CT and intraoral receptors

The aim of this study was to compare cone beam CT (CBCT) in a small field of view (FOV) with a solid-state sensor and a photostimulable phosphor plate system for detection of cavitated approximal surfaces. 257 non-filled approximal surfaces from human permanent premolars and molars were recorded by two intraoral digital receptors, a storage phosphor plate (Digora Optime, Soredex) and a solid-state CMOS sensor (Digora Toto, Soredex), and scanned in a cone beam CT unit (3D Accuitomo FPD80, Morita) with a FOV of 4 cm and a voxel size of 0.08 mm. Image sections were carried out in the axial and mesiodistal tooth planes. Six observers recorded surface cavitation in all images. Validation of the true absence or presence of surface cavitation was performed by inspecting the surfaces under strong light with the naked eye. Differences in sensitivity, specificity and agreement were estimated by analysing the binary data in a generalized linear model using an identity link function. A significantly higher sensitivity was obtained by all observers with CBCT (p < 0.001), which was not compromised by a lower specificity. Therefore, a significantly higher overall agreement was obtained with CBCT (p < 0.001). There were no significant differences between the Digora Optime phosphor plate system and the Digora Toto CMOS sensor for any parameter. CBCT was much more accurate in the detection of surface cavitation in approximal surfaces than intraoral receptors. The differences are interpreted as clinically significant. A CBCT examination performed for other reasons should also be assessed for approximal surface cavities in teeth without restorations.

Patient discomfort in bitewing examination with film and four digital receptors

The aim was to compare patient discomfort during bitewing examination using five intra-oral receptors: a conventional film, a storage phosphor plate with a new soft cover, an already manufactured and sold sensor with a wire and two square and two rounded corners, a new version of a previously developed sensor with a wire and four square corners, and a newly developed sensor with a wire and four rounded corners. 60 patients participated in the study. The five receptors [a Kodak paper pack film (Eastman Kodak Company, Rochester, NY), a DIGORA® Optime phosphor plate (Soredex, Tuusula, Finland), and SuniRay (Suni Medical Imaging, Inc., San Jose, CA), DIGORA Toto (Soredex) and Snapshot (Instrumentarium Dental, Tuusula, Finland) complementary metal-oxide-semiconductors] with differences in ergonomic shape were placed in the mouth for a bitewing examination for approximately 10 s. The patients rated their discomfort on a 100 mm visual analogue scale after having had each receptor positioned. There was no significant difference in patient discomfort score between the conventional film and the Snapshot sensor (p > 0.05). Both conventional film and Snapshot were significantly less uncomfortable than the other receptors (p < 0.05). No significant difference was seen between the storage phosphor plate and the SuniRay sensor (p > 0.05). The storage phosphor plate was significantly less uncomfortable than the DIGORA Toto sensor (p < 0.05). There was no significant difference in the perception of discomfort between the conventional film and an ergonomically shaped wired sensor with rounded corners.

Patient discomfort and retakes in periapical examination of mandibular third molars using digital receptors and film

The aim was to compare patient discomfort and evaluate the frequency of retakes using intraoral digital receptors and conventional film for radiographic examination of mandibular third molars. Both mandibular third molar regions were examined in 110 patients with 2 of 5 digital intraoral receptors. Discomfort was scored on a visual analog scale (VAS) for each receptor and for film as a reference. If the whole tooth was not imaged on the digital image, a retake was performed using film. t Tests evaluated differences in VAS score, chi-squared tests evaluated differences in frequency of remakes, and logistic regression analyses evaluated factors predisposing for retake. No significant difference existed in VAS scores between right and left sides for film (P = .24). The digital receptors were more uncomfortable than film (P < .001), and CDR-APS was more uncomfortable than Digora (P = .049) and Vista (P = .002). The frequency of retakes was higher for solid-state sensors than photostimulable phosphor plates (PSPs) (P < .018). Gender (P = .022), type of receptor (P < .021), and VAS score (P = .001) were predisposing factors for a retake. Patients accepted film better than digital intraoral receptors, and retake frequency was lower for PSPs compared with solid-state sensors.

Diagnostic accuracy of cone beam computed tomography scans compared with intraoral image modalities for detection of caries lesions

The aim was to compare the caries diagnostic accuracy of two cone beam CT systems (CBCT) with two intraoral receptors, one digital and one film. 100 non-cavitated extracted human teeth were placed with approximal contacts: each row of teeth comprised 1 canine, 1 first and second premolar, and 1 first and second molar. Radiographs of each tooth were recorded using two intraoral modalities: Digora-fmx (Soredex) and film (Kodak Insight), and two CBCT systems: NewTom 3G (Quantitative Radiology) in three fields of view (FOVs): pixel size of 0.36 mm (FOV 12 inches), pixel size of 0.25 mm (FOV 9 inches), pixel size of 0.16 mm (FOV 6 inches); and 3DX Accuitomo (Morita), pixel size of 0.125 (FOV 4 cm). The volumetric data from the CBCT systems were reconstructed and sectioned (0.5 mm) in the mesiodistal tooth plane. Six observers scored approximal and occlusal surfaces for the detection of caries lesions. The teeth were clinically sectioned and microscopy served as the validation tool. Two-way ANOVA tested differences in sensitivity, specificity and overall true score (true positives plus true negatives) between the modalities. Microscopy of approximal surfaces found 63% sound, 31% enamel and 6% dentin lesions; of occlusal surfaces, 6% sound, 59% enamel, 19% dentin lesions and 16% had fillings. For approximal surfaces, NewTom 12 inch and 9 inch images had significantly lower sensitivities than Accuitomo (P < 0.02); and NewTom 9 inch and 6 inch had significantly lower specificities than film and Digora-fmx (P < 0.04). Accuitomo images were not significantly different from film or Digora-fmx images for any of the tested variables (P > 0.2). For occlusal surfaces, the Accuitomo presented a higher sensitivity than the other systems. Specificity and overall true score did not differ (P > 0.06) among the modalities. In conclusion, the NewTom 3G CBCT had a lower diagnostic accuracy for detection of caries lesions than intraoral modalities and the 3DX Accuitomo CBCT. The Accuitomo CBCT had a higher sensitivity than the intraoral systems for detection of lesions in dentin, but the overall true score was not higher.

Detection of simulated periodontal bone gain by digital subtraction radiography with tuned-aperture computed tomography. The effect of angular disparity.

To investigate the influence of angular disparity on observer detection of simulated bone gain in digital subtraction radiography using tuned-aperture computed tomography (TACT). Simulated periodontal defects were created in interproximal and buccal or lingual (tooth-obscured) areas of the premolar and molar regions of a dry human skull. Radiographs were obtained before and after known weights of amorphous bone were added to the defects to simulate bone gain. The skull was positioned in a multidirectional tomographic unit to achieve reproducibility. A series of nine basis images were acquired with a CMOS intra-oral receptor and repeated using angular disparities of 10 degrees, 20 degrees, and 30 degrees. Stacks of TACT slices generated from the basis images were paired for image-registration, histogram-equalization and subtraction using TACT Workbench. Eight calibrated observers randomly assessed the presence or absence of bone gain using a 5-point confidence scale. ROC curves were generated and A(z) values were analysed using ANOVA. There were significant differences in the performance of the observers (P=0.034), defect location (P=0.005), amount of bone gain (P<0.001), angular disparity (P=0.003) and angular disparity x defect location interaction (P=0.019). Mean A(z) values in detecting bone gain were 0.90, 0.85, 0.79 for angular disparities of 10 degrees, 20 degrees, and 30 degrees respectively. Smaller angular disparity provided better detection of bone gain with TACT-subtraction using nine basis-projections. This effect of angular disparity was especially evident with tooth-obscured defects.

Factors influencing the excitatory-masseteric reflex evoked by gingival electrical stimulation in man

An excitatory-masseteric reflex response was evoked by electrical gingival stimulation in five subjects; the reflex had an onset latency of 7.6 ms with a SD of 0.7 ms. The response occurred just prior to the silent or inhibitory period. There was consistent post-inhibitory synchronization of the EMG activity record in all subjects. Several methods were used to demonstrate this short-latency reflex. The first was to average non-rectified EMG activity. The second was to increase the number of receptors which are simultaneously activated by using multiple electrodes so that a greater area of gingiva could be stimulated. A third was to increase the level of excitability of the motoneurons in the masseteric pool by increasing voluntary bite force. Fourthly, the excitatory reflex was evoked during increased-excitatory drive to the pool, with the additional feature that the reflex appeared at a time when no ongoing EMG activity was present in the masseter muscle. Little doubt should now remain concerning the existence of a short latency excitatory reflex from intra-oral receptors to masseteric motoneurons in man.

Reflex control of cat extrinsic and intrinsic tongue muscles exerted by intraoral receptors.

The effects of mechanical and noxious stimulation of the palatal and lingual surfaces on the activity of the extrinsic and intrinsic tongue muscles have been studied in cats. Stimulation of the hard palate produced mainly activation of extrinsic tongue muscles while inhibition was elicited by stimulating the soft palate. Longlasting pressure on the hard palate caused rhythmic tongue flapping by intermittent genioglossal activity. The intrinsic tongue muscles, m. transversus and m. verticalis, were activated by noxious stimuli applied to the hard palate, the effects apparently being mediated by high-threshold afferents. Mechanical and noxious stimulation applied to the dorsal and ventral lingual surfaces of the tongue either activated or inhibited the extrinsic tongue muscles depending on the reflex area stimulated. The intrinsic tongue muscles were activated by noxious stimuli applied to the tongue surfaces. The anastomoses running between the hypoglossal and lingual nerves were found to mediate mainly nociceptive afferent impulses traveling from the hypoglossal to the lingual nerve. The intrinsic muscles were found to be controlled by anastomosal nociceptive afferents.