bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of low-dose digital lateral cephalometric radiographs
Authors: Näslund E B , Kruger M , Petersson A , Hansen K
Published: October 2024

OBJECTIVE

To examine the effects of the dose reduction obtained with photostimulable phosphor computed radiography (CR) on the identification of cephalometric landmarks.

METHODS

Dose reductions of 50% and 75% respectively were obtained by placing three storage phosphor image plates in the same cassette. Lateral cephalograms were exposed on ten patients. Seven observers identified 14 anatomical landmarks on the images.

RESULTS

The location of anatomical landmarks on the lateral cephalograms was not effected by the decreased dose (P > 0.05). Interobserver variation was the major influence.

CONCLUSION

A dose reduction of 75% does not effect the localization of anatomical landmarks in lateral cephalograms obtained with CR.
Advantage of appropriate K-edge filters for one-shot dual-energy subtraction sialography
Authors: Kobayashi S
Published: October 2024

OBJECTIVES

To determine the optimal added filtration for use for one-shot dual energy subtraction sialography.

METHODS

Test phantoms composed of bone and soft tissue materials were imaged with computed radiography using one-shot dual energy subtraction radiography. Eight different additional filter materials were compared with gadolinium contrast. Two numerical measures (absorption ratio and separation index) were used to compare the subtracted images obtained with the various filter/contrast combinations. The K-edge spectra were measured for each filter/contrast combination. A preliminary comparison of a 1.5 M iodine contrast medium with a 1.5 M gadolinium was performed using canine sialography.

RESULTS

The gadolinium contrast/samarium filter combination had a larger separation index (P < 0.05). The same combination yielded better sialograms than iodine contrast.

CONCLUSIONS

Samarium filter has an optimal k-edge for one-shot dual-energy sialography with gadolinium contrast.
The development of a new direct digital extra-oral radiographic system prototype using a thin-film transistor panel
Authors: Sakurai T , Matsuki T , Nakamura K , Kashima I , Lee D L , Cheung L K , Jeromin L S
Published: October 2024

OBJECTIVE

To develop a new method of direct digital image acquisition for extra-oral radiography.

METHODS

A selenium detector was combined with a thin-film transistor sensor and integrated with current technology for computed radiography in a system named Direct Radiography (DR). The effective image area of the prototype is 178 mm x 213.5 mm, and consists of a 1280 x 1536 pixel matrix with a pixel pitch of 139 microns x 139 microns. The electrical characteristics were evaluated and image quality was tested with a dried human mandible and half-skull phantom. The resultant images were subjectively reviewed by seven oral and maxillofacial radiologists.

RESULTS

The prototype had a signal-to-noise ratio of 400:1 when the exposure was 250 x 10(-8) C/Kg. Spatial resolution was equal to the Nyquist frequency of 3.55 cycles/mm. The images of the phantoms were considered to be of equivalent quality to conventional screen-film images and demonstrated the normal anatomical structures used for clinical evaluation. Three to four images per minute were generated with this system.

CONCLUSION

The DR system has an X-ray sensitivity comparable with a 400-speed film-screen system and appears suitable for clinical radiography. Further evaluation is therefore planned.
Adverse reactions to nonionic iodine in contrast-enhanced computed tomography: usefulness of monitoring vital signs
Authors: Kurabayashi T , Ida M , Fukayama H , Ohbayashi N , Yoshino N , Sasaki T
Published: October 2024

OBJECTIVE

To report on adverse reactions to intravenous nonionic iodine contrast media and evaluate the usefulness of monitoring vital signs.

MATERIAL AND METHODS

A prospective study of 1537 consecutive patients who received contrast-enhanced CT with nonionic iodine was performed. Systolic and diastolic arterial blood pressure, pulse rate and arterial blood oxygen saturation were monitored. Severity of adverse reactions was classified as minor, intermediate and severe.

RESULTS

A total of 64 adverse reactions developed in 57 patients. The overall prevalence was 3.7% (57/1537). The most common symptom was nausea (18/64) followed by pharyngeal discomfort (11/64). One patient had a severe reaction consisting of prolonged hypotension. Four patients had an intermediate reaction, three transient hypotension or hypertension and one extensive urticaria and facial edema. In two out of four patients who became hypotensive or hypertensive, the reactions developed without any obvious clinical symptoms.

CONCLUSIONS

Severe or life-threatening acute adverse reactions to intravenous nonionic iodine contrast media may develop without any obvious clinical symptoms. Monitoring vital signs is very helpful for early detection.
The role of three-dimensional spiral computed tomography in oral metastases
Authors: Cavalcanti M G , Vannier M W
Published: October 2024

We present the spiral 2DCT and 3DCT imaging findings in two patients with oral metastases, one with breast and the other with prostate cancer. In order to demonstrate the contribution of these techniques in the evaluation and treatment planning of such lesions. 3DCT can help to define further the extent of osteolytic involvement noted on initial 2DCT images, allowing better localization and visualization of the anatomical regions involved. We conclude that 3DCT is a useful adjunct for the management of maxillofacial tumors involving bone.
Comparison of reliability of manual and computer-intensive methods for radiodensity measures of alveolar bone loss
Authors: Hildebolt C F , Brunsden B , Yokoyama-Crothers N , Pilgram T K , Townsend K E , Vannier M W , Shrout M K
Published: October 2024

OBJECTIVE

To compare the reliability of radiodensity measurements made from dental radiographs with manual and a novel computer-intensive methods.

METHODS

As part of a prospective study of postmenopausal women, a series of seven vertical bitewing radiographs were taken of 36 patients. One of each set of radiographs was repeated. The original and the corresponding duplicate radiographs were used in this study. Radiographs were digitized at 50 microns spatial resolution and 12-bit gray-scale resolution. For the Manual Method, original and duplicate radiographs were manually cropped to improve image homology, histogram matched and mean pixel gray-scale values determined for an alveolar bone ROI within each image. For the computer-intensive method, images were put into registration with ANALYZE software (Mayo Foundation, Rochester, MINN, USA), cropped automatically, histogram matched and color-coded on the basis of the per cent difference. Alveolar bone ROIs adjacent to clinical crowns and root surfaces whose color code indicated less than a 5% change were sampled. Method error (ME) and the coefficient of variation of method error (CVME) were calculated.

RESULTS

With the Manual Method the SD between original and duplicate measures was 95.21 out of 4096 gray scale values; ME = 67.32; CVME = 3.78%. For the computer-intensive method, the corresponding values were 54.74, 38.71, and 2.29%.

CONCLUSIONS

The new computer-intensive method resulted in a 40% improvement over the Manual Method in the precision of radiodensity measurements.
Radiographic assessment of changes in marginal bone around endosseous implants supporting mandibular overdentures
Authors: Batenburg R H , Meijer H J , Geraets W G , van der Stelt P F
Published: October 2024

OBJECTIVES

To evaluate the reliability of a new method for quantification of radiographic changes in the marginal bone around implants.

METHODS

Three groups of seven patients treated with an overdenture supported by two endosseous implants (Brnemark, n = 7 patients; IMZ, n = 7 patients; ITI Bonefit, n = 7 patients) were selected. Six weeks after loading the implants, radiographs were obtained using the long cone technique and an aiming device, scanned and digitized. Two observers measured the height and area of the peri-implant bone defects twice. The difference between measurements was statistically analysed using paired t-tests.

RESULTS

There were small differences in interobserver error for the Brnemark implant system (P < 0.05), but no significant differences for the IMZ and ITI Bonefit. There were no significant difference in intraobserver error with any of the three implant systems (P > 0.05).

CONCLUSIONS

The newly developed technique by measuring the area of the defect overcomes some drawbacks of existing techniques for quantification of peri-implant bone loss in the mandible.
Low-field magnetic resonance imaging for implant dentistry
Authors: Gray C F , Redpath T W , Smith F W
Published: October 2024

OBJECTIVE

To evaluate the use of a low-field magnetic resonance scanner for assessment of available bone for placement of osseo-integrated dental implants.

METHODS

Eleven Patients were examined to assess suitability for implant placement using a 0.2 tesla 'open' scanner. Imaging/surgical templates were constructed, with gadolinium markers to allow accurate location of the implant sites.

RESULTS

In all cases, localisation of potential implant sites was easily made and full information in all three planes readily available. Artefacts were few and localised, (noted on one site in one case only). Vital structures (nerves and vessels), and the variable geometry of the floor of the maxillary sinus were clearly seen, and cortical bone delineated from cancellous. The appearance of soft tissues in the scan allowed the surgeon to assess the final profile of the patient.

CONCLUSION

Low-field magnetic resonance imaging has definite potential for pre-implant assessment. Full sectional information is readily available at any desired plane with no need for reformatting. The information for accurate and safe implant placement is clear. The technique uses no ionising radiation. Further work is needed to evaluate spatial distortion caused by magnetic susceptibility effects at air/tissue interfaces, but our calculations indicate that at low field, using an appropriate protocol, the effect will not be substantial.
An evaluation of digital subtraction radiography for assessment of changes in position of the mandibular condyle
Authors: Ekberg E C , Petersson A , Nilner M
Published: October 2024

OBJECTIVE

To compare conventional visual evaluation with digital subtraction for assessing changes in condylar position on TMJ radiographs.

METHODS

Horizontally corrected oblique lateral transcranial radiographs of the TMJ were taken bilaterally with and without a stabilisation or a control appliance on the same occasion in 20 patients. All of the radiographs were assessed both conventionally and following digital subtraction by seven observers. Three observers assessed both sets of radiographs twice to calculate observer agreement.

RESULTS

There were no statistically significant differences in observer performance or diagnostic outcome between the two techniques. Intra-observer agreement varied between 85 and 90% for the conventional visual evaluation and between 62 and 85% for digital subtraction. Although interobserver agreement was greater with the conventional evaluation the difference was not significant.

CONCLUSION

Conventional visual evaluation is recommended for the assessment changes in condylar position from TMJ radiographs.
A longitudinal study of idiopathic osteosclerosis and condensing osteitis
Authors: Williams T P , Brooks S L
Published: October 2024

OBJECTIVE

To document the prevalence of idiopathic osteosclerosis (IO) and condensing osteitis (CO) in a middle-age-to-older adult population and determine their long term behavior.

STUDY DESIGN

Full-mouth radiographs of 1585 adults, with a mean age 44.0 years, were evaluated for the presence of radiopaque masses diagnosed as IO or CO. All lesions were followed for 2 to 28 years, mean 10.4, to determine changes in size and shape.

RESULTS

There were 187 lesions detected, 100 IO in 90 subjects (5.7%) and 87 CO in 71 subjects (4.5%). At follow-up, 180 lesions (96%) were still present, of which 155 were unchanged in size, 18 were smaller, and 7 were larger.

CONCLUSIONS

Idiopathic osteosclerosis in middle age to older adults is stable and requires no further action after documentation in the patient's clinical records.
Validation of spiral computed tomography for dental implants
Authors: Cavalcanti M G , Yang J , Ruprecht A , Vannier M W
Published: October 2024

OBJECTIVES

To investigate the accuracy of 2DCT orthoradial reformatted images from spiral computed tomography (CT) for pre-surgical planning of dental implants in proximity to the mental foramen.

METHODS

Eight cadaver heads were imaged by spiral CT (S/Xpress, Toshiba-America, Tustin, CA) with 1 mm thick axial slices by 1 mm/sec of table feed. The image data set was transferred to a networked computer workstation. Using computer graphics the data was analysed with 2D orthoradial reformatting using the ToothPix (Cemax, Fremont, CA, USA) protocol. Linear measurements were made by two oral radiologists independently from the superior border of the mental foramen to the crest of the alveolar process and from the inferior border of the mental foramen to the mandibular inferior border. The soft tissues were removed and physical measurements made using a 3 Space (Polhemus, Colchester, VT) electromagnetic digitizer with a personal computer running Windows 95.

RESULTS

The differences between the measurements on orthoradial 2DCT images and the physical measurements were not statistically significant (P > 0.05).

CONCLUSIONS

Two-dimensional spiral CT imaging allows highly accurate measurements for dental implant placement in proximity to the mental foramen. Computer graphics software, using reformatted reconstruction, is suitable for implant planning.
Sources of radiographic distortion in conventional and computed tomography of the temporal bone
Authors: Ahlqvist J , Bryndahl F , Eckerdal O , Isberg A
Published: October 2024

OBJECTIVES

To identify those bony regions of the glenoid fossa where, due to the inclination, there is an increased risk of radiographic distortion in conventional and computed tomography (CT).

METHODS

The inclination of the roof and posterior wall of the glenoid fossa was determined relative to established imaging planes. Measurements were performed on 50 corrected coronal MR and 50 axial CT images and 200 sagittal cryosections of 50 temporomandibular joints (TMJs). The location of regions with unfavourable bone wall inclination was identified using the condyle as a reference.

RESULTS

The inclination of parts of the fossa roof exceeded the limit for reliable depiction in corrected sagittal and coronal planes in 40% and 8% of the joints respectively. The inclination of parts of the posterior wall of the fossa exceeded the limit for reliable depiction in corrected sagittal and in true sagittal planes in 100% and 84% of the joints respectively. In 84% of the joints the inclination exceeded the limit for reliable depiction in the axial plane. For both bone walls the regions with unfavourable inclination were in the medial part of the joint.

CONCLUSIONS

The angulation of parts of the roof and posterior wall of the glenoid fossa in relation to established imaging planes makes them highly susceptible to distortion. The oblique coronal projection is well suited for depiction of the roof of the fossa and preferable to a sagittal projection. An oblique axial projection is required for the posterior wall.
Effects of developer exhaustion on the sensitometric properties of four dental films
Authors: Syriopoulos K , Velders X L , Sanderink G C H , van Ginkel F C , van der Stelt P F
Published: October 2024

OBJECTIVES

To examine the effects of exhaustion of five different processing solutions on the sensitometric properties of four dental X-ray films: Ektaspeed Plus and Ultra-speed (Kodak Eastman Co. Rochester, USA) and new and previous Dentus M2 (Agfa-Gevaert, Mortsel, Belgium).

METHODS

An aluminum stepwedge was used to construct characteristic curves for the four films. All films were processed manually using three sets of chemicals for manual processing: Agfa (Heraeus Kulzer, Dormagen, Germany), Kodak (Kodak-Pathé, Paris, France) and Demat (Viscopac, Athens, Greece) and two sets for automatic processing: Dürr XR and Periomat (Dürr Dental, Bietigheim-Bissingen, Germany). Film speed and gradient were evaluated until the chemicals were completely exhausted. An analysis of variance was performed separately for each set of chemicals for manual and automatic processing.

RESULTS

Ektaspeed Plus was the fastest film in the manual processing solutions. The new Dentus M2 and Ektaspeed Plus films had similar speed using the chemicals for automatic processing. Ultra-speed had the lowest speed in all solutions, but it had the greatest consistency. Exhaustion of the developer caused a comparable decrease in speed of Ektaspeed Plus and the two Dentus M2 films. In fresh chemistry Agfa was the strongest manual processing solution, but it had the highest exhaustion rate. The Dürr XR chemical was stronger than Periomat over the whole test period.

CONCLUSIONS

The combination of film and processing solution is an important factor for achieving constant sensitometric properties. Ektaspeed Plus and the new Dentus M2 film should be used in dental practice, as they require lower exposure and have equivalent or superior properties compared with Ultra-speed.
Dental students' ability for three-dimensional perception of two-dimensional images using natural stereopsis: its impact on radiographic localization
Authors: Wenzel A
Published: October 2024

OBJECTIVES

To investigate the ability of dental students to perceive 2D images in 3D using natural stereopsis and to evaluate whether the use of stereovision influences their interpretation of radiographic depth, with particular reference to intra-oral radiographs of third molars compared with scanograms.

METHODS

Seventy-two dental students (37 from sixth semester and 35 from fourth semester) who had all completed a course in the use of the buccal-object rule participated in the study. Lectures in 3D perception were given to the sixth semester students. They were trained in 3D perception using a 'single image colour field' stereogram and classical stereograms of circles. Both semester students diagnosed nine scanograms and nine intra-oral radiographs for: (1) the position of the crown of an impacted third molar in relation to the second molar and (2) root deviations in the bucco-lingual plane. The sixth semester students recorded whether they were able to achieve a 3D image in these cases.

RESULTS

Five students could not achieve a depth image from the training stereograms. Fifty-six per cent agreed on which two objects in the circles were nearest to the viewer and which were most distant, whereas 38% agreed on the opposite. Root deviation was a more difficult diagnostic task than crown position, and the sixth semester students made significantly more correct diagnoses than the fourth semester students (P < 0.001). Irrespective of semester, there was no significant difference between number of correct diagnoses of crown alignment in intra-oral radiographs and scanograms (P = 0.57), whereas root deviations were diagnosed significantly more accurately from the intra-oral radiographs (P < 0.001).

CONCLUSIONS

Most dental students can be taught to use natural stereovision to achieve a 3D image from two radiographs at different angles. 3D image is achieved equally well from intra-oral radiographs with a free-hand tube shift and scanograms. Those students who achieved a 3D image in a particular case, made more correct diagnoses than those who could not.
Predictability of a three-dimensional planning system for oral implant surgery
Authors: Jacobs R , Adriansens A , Verstreken K , Suetens P , van Steenberghe D
Published: October 2024

OBJECTIVES

To compare 2D CT alone with 2D + 3D reconstruction for pre-operative planning of implant placement.

METHODS

Spiral CT scans of 33 consecutive patients were used for both reformatted 2D and 3D computer-assisted planning. The number, site and size of implants and the occurrence of anatomical complications during planning and implant placement were statistically compared using the percentage agreement and the Kendall's correlation coefficients (tau). Although planning was performed in 33 patients, implants were only placed in 21 patients. In 11 patients surgery was based on 2D + 3D imaging and in ten patients on 2D planning.

RESULTS

Agreement between planning and placement of implants was highly significant for the implant sites selected. For 2D based planning and placement, agreement reached 68% (tau = 0.94). For 2D + 3D based planning and placement, agreement attained 73% (tau = 0.89). For planning and placement of implant size based on 2D images, agreement was 31% and not significant (tau = 0.23). When based on 2D + 3D images, agreement for implant size was 44% (tau = 0.5). Agreement was not significant for anatomical complications: 69% for 2D planning and 71% for 2D + 3D planning (tau = 0.24 for 2D and tau = 0.21 for 2D + 3D).

CONCLUSIONS

The 3D planning system is a reliable tool for pre-operative assessment of implant placement. Both 2D and 2D + 3D planning have a good predictability for the number and site of the implants but less so for anatomical complications. However, the 2D + 3D planning provides a better pre-operative assessment of implant size.
A simplified method to obtain perceptibility curves for direct dental digital radiography
Authors: Stamatakis H C , Yoshiura K , Shi X Q , Welander U , McDavid W D
Published: October 2024

OBJECTIVES

To derive and test a simplified method to construct Perceptibility Curves (PCs) for dental digital detectors.

METHODS

Mathematical expressions were derived to make it possible to construct PCs from viewer data obtained at two exposures, one low and one high. PCs were constructed applying these expressions and compared with data previously obtained employing the conventional method.

RESULTS

PCs constructed according to the simplified method agree extremely well with conventionally obtained data.

CONCLUSIONS

Reliable PCs may be constructed according to the simplified method.
Accurate linear measurements in the anterior maxilla using orthoradially reformatted spiral computed tomography
Authors: Cavalcanti M G P , Yang J , Ruprecht A , Vannier M W
Published: October 2024

OBJECTIVES

To validate measurement accuracy in proximity to the incisive canal from two-dimensional (2D) reformatted spiral computed tomography (CT).

MATERIALS AND METHODS

Eight cadaver heads were examined with spiral CT with 1 mm thick axial slices and 1 mm.s-1 table feed. The data was transferred to a networked computer workstation to generate 2D orthoradially reformatted images. The length of the incisive canal and width of the alveolar crest were measured independently by two oral and maxillofacial radiologists. The soft tissues in the region of the incisive foramen were removed and physical measurements made using an electromagnetic digitizer.

RESULTS

There was no statistically significant difference between measurements on orthoradial 2DCT images and physical measurements (P > 0.05).

CONCLUSIONS

Accurate measurements for dental implant placement in proximity to the incisive canal can be made from reformatted spiral CT images.
Frequency of portrayal of foramen transversarium of the second cervical vertebra on rotational panoramic radiographs
Authors: Timmons S R , Ruprecht A , Deahll S T
Published: October 2024

OBJECTIVES

To determine the prevalence of portrayal of the foramen transversarium of the second cervical vertebra on rotational panoramic radiographs.

METHODS

A stratified random sample of 1600 diagnostic-quality rotational panoramic radiographs were retrospectively reviewed. Approximately 100 radiographs each for males and females were reviewed for each of the decades of life up to age 69 and for subjects 70 or older.

RESULTS

The foramen was portrayed 29.3% of all radiographs, 35% of females and 22.6% of males. However, when considering only those radiographs in which cervical vertebrae were visible, the foramen was more frequently portrayed in males than in females. Portrayal of the foramen did not differ substantially among age groups.

CONCLUSIONS

The foramen transversarium is found sufficiently often on rotational panoramic radiographs that this structure should be identifiable by clinicians who use these images.
Radiological and clinical features of aneurysmal bone cyst of the jaws
Authors: Kaffe I , Naor H , Calderon S , Buchner A
Published: October 2024

PURPOSE

To evaluate the clinical and radiological features of aneurysmal bone cyst (ABC) of the jaws.

MATERIALS AND METHODS

A total of 64 cases (60 from the English-language literature and four new cases) were studied and critically evaluated with emphasis on the radiological features.

RESULTS

Age at time of initial diagnosis ranged from 4-78 years, with a mean age of 21.5 years and median age of 17 years. There were no differences in gender distribution. The ratio between the mandible and maxilla was 2.4:1. Ninety-two per cent of the lesions were located in the posterior region of the jaws. Lesions were radiolucent in 87% of cases, radiopaque in 2% and mixed in 11%. Fifty-three per cent were multilocular, 43% unilocular and 3% not loculated. The border of the lesions was defined but not corticated in 39%, well defined in 33% and diffuse in 28%.

CONCLUSIONS

ABC has a variable radiological appearance and should be considered in the differential diagnosis of any unilocular or multilocular radiolucent lesion of the jaws as well as any mixed radiolucent-radiopaque lesion.
Influence of the digital image display monitor on observer performance
Authors: Cederberg R A , Frederiksen N L , Benson B W , Shulman J D
Published: October 2024

OBJECTIVE

To assess the influence of the display monitor on observer performance.

MATERIAL AND METHODS

Artificial enamel lesions were created in 40 extracted teeth at random using 1/4 and 1/2 round burs. Teeth were mounted in dental stone blocks to simulate a hemidentition. Approximate exposures were recorded at 70 kVp using a Digota (Soredex, Orion Corp, Helsinki, Finland) digital imaging system, calibrated to achieve optimum density. Six dentists rated each image on a five-point scale for the presence or absence of a lesion. Radiographic images were viewed on the following monitors: (1) AlphaScan 711 (Sampo Corp.); (2) Multiscan 17 Se II (Sony Electronics Inc.); (3) DS 2000 (Clinton Electronics Corp.) and (4) Latitude CP Laptop (Dell Computer Corp.). Raters were allowed to magnify and to adjust density and contrast of each image at will. Receiver Operating Characteristic (ROC) analysis was performed and curves were plotted for each image. Data was subjected to repeated measures analysis of variance and ordinal logistic regression to test for significance between variables and to determine odds ratios.

RESULTS

Mean ROC curve areas ranged from 0.8728 for the Sampo monitor to 0.8395 for the Sony. Repeated measures analysis of variance showed significant differences between observers (P < 0.0001), lesion size (P < 0.0001), examiner/monitor interaction (P < 0.033) and examiner/block interaction (P < 0.013). However, no significant difference was found between monitors.

CONCLUSION

This study suggests that observer performance is independent of the visual characteristics of the display monitor.
The effect of developer age on the detection of approximal caries using three dental films
Authors: Syriopoulos K , Velders X L , Sanderink G C , van Ginkel F C , van Amerongen J P , van der Stelt P F
Published: October 2024

OBJECTIVES

To compare the diagnostic accuracy for the detection of approximal caries of three dental X-ray films using fresh and aged processing chemicals.

METHODS

Fifty-six extracted unrestored premolars were radiographed under standardized conditions using the new Dentus M2 (Agfa-Gevaert, Mortsel, Belgium), Ektaspeed Plus and Ultra-speed (Kodak Eastman Co, Rochester, USA) dental films. The films were processed manually using Agfa chemicals (Heraeus Kulzer, Dormagen, Germany). The procedure was repeated once a week until the complete exhaustion of the chemicals (6 weeks). Three independent observers assessed 210 radiographs using the following rating scale: 0 = sound, 1 = enamel lesion; 2 = lesion reaching the ADJ; 3 = dentinal lesion. True caries depth was determined by histological examination (14 sound surfaces, 11 enamel lesions, eight lesions reaching the ADJ and 23 dentinal lesions). True caries depth was subtracted from the values given by the observers and an analysis of variance was performed. The null hypothesis was rejected when P < 0.05.

RESULTS

No significant differences were found in the diagnostic accuracy between the three films when using chemicals of up to 3 weeks old (P = 0.056). After the third week, Ultra-speed was significantly better than the other two films (P = 0.012). On average caries depth was underestimated.

CONCLUSION

A similar level of diagnostic accuracy for approximal caries is achieved when using the three films. Dentus M2 and Ektaspeed Plus are at present the fastest available films and they should therefore be recommended for clinical practice. Agfa chemicals should be renewed every 3 weeks. Fifty per cent reduction in average gradient is indicative of renewing processing chemicals.
Progression of maxillofacial squamous cell carcinoma evaluated using computer graphics with spiral computed tomography
Authors: Cavalcanti M G , Ruprecht A , Quets J
Published: October 2024

This report describes the appearance of maxillofacial squamous cell carcinoma in multiplanar (MPR) and three-dimensional (3D) images reconstructed from spiral CT using computer graphics and the importance of the computer software tools in permitting better visualization of the lesion. Two oral and maxillofacial radiologists and one neuroradiologist analysed the images. The usefulness of interactive reconstruction in the diagnosis, surgical planning and treatment evaluation, especially in the localization of the extent of these maxillofacial tumors, was demonstrated. Spiral CT-based computer graphics for displaying MPR and 3D images are an important adjunct in the evaluation of squamous cell carcinoma.
Effects of collimator size of a dental X-ray unit on image contrast
Authors: Falk A , Lindhe J E , Rohlin M , Nilsson M
Published: October 2024

OBJECTIVES

To examine the effect of collimator size on image contrast in dental radiography.

METHODS

Two conventional collimators, one circular (53 mm in diameter) and one rectangular (35x45 mm2), were compared with a small rectangular collimator (26x39 mm2). Low-contrast and high-contrast resolution was assessed with the aid of contrast-detail and line-pair phantoms.

RESULTS

Shallower holes were observed with the small rectangular collimator. Two-thirds of 17 observers assessing high-contrast resolution considered the small collimator to result in a clearer image than the conventional collimators. The same effect was demonstrated with the line-pair phantom and by microdensitometry. With the small collimator the energy imparted is estimated to be reduced by 54 and 36% compared with the conventional circular and rectangular collimators respectively.

CONCLUSIONS

Decrease of the collimator size to fit the film size used for children will result in improved low-contrast and, under some conditions, improved high-contrast resolution. This improvement might have implications for caries diagnosis and monitoring.
Fractal dimension calculated from two types of region of interest
Authors: Lee K I , Choi S C , Park T W , You D S
Published: October 2024

OBJECTIVES

To compare the effect of using two region of interest (ROI) types on calculating the fractal dimensions of trabecular bone during simulated osteoporosis.

METHODS

Ten 5 mm thick cross-sections from the long bone of a cow were progressively decalcified in 0.1 N Hcl for 5, 10, 20, 30, 60 and 90 min intervals, and radiographed using 0 degrees projection angle in a specially designed device. Two types of ROI (the ruggedness of the boundary and bone profiles) were placed on each digital image. Fractal dimensions and variance in mean pixel intensity were computed from each ROI using the caliper method in ImageFractal (National Institutes of Health, Washington, DC, USA). Correlation analysis quantified the relationship between changes in variance and fractal dimensions of the two types of ROI.

RESULTS

A Strong correlation (r=0.90 approximately 0.98, P</=0.0026) was found between variance in mean pixel intensity and decreasing fractal dimensions calculated from bone profiles. There was no consistency in the ruggedness of the boundary and increasing decalcification.

CONCLUSIONS

The fractal dimensions used to characterize the ruggedness of a boundary of trabecular bone in a two-dimensional ROI are inadequate for the detection of osteoporosis, but those calculated from bone profiles may be a sensitive descriptor of trabecular bone structure.
Mandibular osteoradionecrosis: a comparison of computed tomography with panoramic radiography
Authors: Store G , Larheim T A
Published: October 2024

OBJECTIVES

To compare the value of computed tomography (CT) with panoramic radiography in the diagnosis and presurgical evaluation of mandibular osteoradionecrosis (ORN).

METHODS

Retrospective study comparing the diagnostic information from CT and panoramic radiography of 33 patients with clinical symptoms of ORN. In six patients the imaging was compared macroscopically with the resected mandible.

RESULTS

Both panoramic radiography and CT revealed ORN in 31 cases. In 22 the anterior-posterior extent of the lesions could be estimated with equal reliability. In six patients the lesion appeared larger on CT and in three on panoramic radiography. Mono- or bicortical destruction, central necrosis and sequestration were better visualized by CT. Comparison between the imaging findings and the surgical resection showed that CT depicted the topography of the specimen more accurately.

CONCLUSIONS

CT is superior to panoramic radiography in visualizing the features of mandibular ORN and the anterior-posterior extent of the lesion.
A method for correcting for errors produced by variable magnification in three-dimensional tuned-aperture computed tomography
Authors: Webber R L , Bettermann W
Published: October 2024

OBJECTIVES

To develop and test a method for correcting tomosynthetic misregistration caused by variation in projective magnification.

METHODS

A tooth from a monkey was radiographed from various angles and distances using a solid-state sensor to which a plastic spacer with a wire frame was attached. The position of the tooth was fixed relative to both the frame and the sensor. Information derived from the frame's shadow was used to produce a series of tomosynthetic slices using tuned-aperture computed tomography (TACT(R)). One series was corrected for magnification errors and the other was not. Corresponding slices from each series were compared.

RESULTS

The corrected slice exhibited much less artifactual blur than its uncorrected counterpart. Linear traces through corresponding portions of these slice images demonstrated discrepancies in homologous dimensions attributable to systematic variations in projective magnification.

CONCLUSIONS

Correcting for differences in projective magnification reduces both misregistration and scaling artifacts in tomosynthetically reconstructed volumes.
Reproducible X-ray projection geometry in edentulous patients
Authors: Handschel J , Kleinheinz J , Kelker M , Reuter I , Joos U
Published: October 2024

OBJECTIVE

To evaluate a novel fixation system for reproducible radiography in edentulous patients.

METHODS

A conventional extra-oral fixation system was modified with a filmholder and adjustable scales. For measuring reproducibility and angulation errors two rods and two balls were fixed on the alveolar crests of the maxilla and the mandible and angular variations were measured. One hundred radiographs of a conventional phantom were taken by one of the authors and by ten dental students. The angular disparity was calculated and intra- and interoperator precision determined.

RESULTS

The average time taken to assemble the fixation system was 4 min. The 95% confidence interval for precision of the single operator was less than 2.5 degrees in both the maxilla and mandible. The 95% confidence interval for precision of the ten students was less than 2.2 degrees for the maxilla and 2.7 degrees for the mandible. There was no significant difference (P>0.05) in interoperator precision.

CONCLUSION

The novel extra-oral fixation system appears to be a potential means of obtaining reproducible radiographs of edentulous patients.
Cyclopia and exadactyly: CT and MRI findings.
Authors: Karantanas A H , Papanikolaou N , Danos A , Antonakopoulos G
Published: October 2024

Cyclopia is a congenital abnormality consisting of fused orbits and a single eye and is the most extreme form of alobar holoprosencephaly. The present case describes the CT and MRI findings in the skull of a 33-week-old cadaver with alobar holoprosencephaly and exadactyly.
An electronic survey of opinions on the compatibility of current X-ray generators with intra-oral digital X-ray systems
Authors: Hayakawa Y , Kuroyanagi K , Chen S K , Farman A G , Welander U
Published: October 2024

OBJECTIVES

To assess opinions on the compatibility of current X-ray generators with intra-oral digital X-ray systems.

METHODS

A questionnaire was posted in both English and in Japanese on oral and maxillofacial radiology electronic bulletin boards. The questionnaire was also mailed to selected researchers and manufacturers in oral and maxillofacial radiology. The replies were evaluated to determine opinion on the current and future status of digital intra-oral imaging with special reference to their compatibility with current X-ray generators.

RESULTS

Seventy-one replies were received from 19 countries: 39% from Japan and Korea, 27% from North America, 25% from Europe and 8% from the rest of the world. Eighty per cent of respondents were from academia, 15% from industry and the remainder largely in private practice. Respondents' experience was equally divided between solid state, mainly charge-coupled devices (CCDs) and photostimulable phosphor (IP) technologies. Sixty-eight per cent considered that current X-ray generators are compatible with intra-oral digital systems and many believed this was due to their gray scale flexibility. Twenty-eight per cent believed that existing X-ray generators are inconsistent with low exposure times. Many of the replies suggested that in future pixel size would decrease and bit depth and receptor sensitivity increase.

CONCLUSIONS

Most respondents are happy to use existing X-ray generators with digital X-ray systems. However, they also believe that increased sensitivity of receptors could lead to more stringent designs of X-ray generators to ensure more reliable outputs in the low exposure range.
Interrelationship between cross-sectional and sagittal imaging in computer-assisted dental implant tomography
Authors: Thunthy K H
Published: October 2024

OBJECTIVE

To determine what changes may occur in computer-assisted dental tomography to cross-sectional and sagittal slices when the positions of one or both slices are adjusted.

METHODS

A human skull with a ball bearing attached to the mandibular first molar was positioned off-centre in a CommCAT (Imaging Sciences International, Hatfield, PA, USA) tomographic machine. An occlusal projection of the mandibular dental arch was scanned into the computer. Correction measurements obtained from scout cross-sectional and sagittal slices were used to 'customize' cross-sectional and sagittal slices simultaneously and also individually.

RESULTS

The resulting changes in position and blur of the ball bearing were analysed. When simultaneously and correctly customized, the resultant slices were at the correct locations with a sharp image of the marker. When the sagittal slice only was adjusted, the blur of the marker changed, but its position remained unchanged; at the same time, the blur of the marker in the cross-sectional slice remained unchanged, but its position changed. When the cross-sectional slice only was adjusted, the blur changed, but its position remained unchanged; at the same time, the blur of the marker in the sagittal slice remained unchanged, but its position changed.

CONCLUSIONS

It is important for dentists evaluating tomograms for implant placement to be aware that with the CommCAT tomographic machine an interrelationship exists between cross-sectional and sagittal slices and that adjustment in one type of slice produces changes in either the blur or position of the marker in the adjusted and unadjusted slices.
Subjective image quality of solid-state and photostimulable phosphor systems for digital intra-oral radiography
Authors: Borg E , Attaelmanan A , Gröndahl H G
Published: October 2024

OBJECTIVES

To compare subjectively the image quality of intra-oral radiographs from six digital systems.

METHODS

Two generations of two different solid-state detectors; Visualix-1 and -2 (Gendex Dental Systems, Milan, Italy), Computed Dental Radiography (CDR) and CDR Active Pixel Sensor (APS) (Schick Technologies Inc., Long Island City, NY, USA), and two photostimulable phosphor (PSP) systems; Digora (Soredex, Orion Corporation, Helsinki, Finland) and DenOptix (Gendex Dental Systems, Milan, Italy) were compared. Tooth-containing specimens from different areas of dried mandibles were radiographed at exposures between 91-9400 microGy. Images were transferred to a personal computer, displayed in random order and evaluated in their original form and after applying a histogram equalisation algorithm. Eight observers graded subjective image quality using a 5-point scale.

RESULTS

Both CDR systems scored highest for image quality but within the narrowest exposure range. The Visualix images received the lowest scores. The PSP systems produced acceptable image quality at both lower and higher exposures than the solid-state systems. Enhanced images were generally considered to be inferior to the original images, except for those produced by the four solid-state systems at very low exposures.

CONCLUSIONS

(i) the PSP systems provided a clinically acceptable image quality over a wide exposure range; (ii) the CDR systems had the best image quality but over the narrowest exposure ranges; (iii) the Visualix systems had the lowest image quality; and (iv) histogram equalisation did not generally improve image quality.
A clinical evaluation of some factors affecting image quality in panoramic radiography
Authors: Kaeppler G , Axmann-Krcmar D , Reuter I , Meyle J , Gómez-Román G
Published: October 2024

AIM

To evaluate the suitability of panoramic radiographs obtained with two different machines for clinical use.

MATERIAL AND METHODS

Three observers assessed 111 pairs of panoramic radiographs taken with the Scanora (Soredex, Orion Corp., Helsinki, Finland) programme 001, and the Orthophos Plus (Sirona, Bensheim, Germany), programme P1 respectively, for visualisation of seven anatomical structures on each side, on a 5-point scale where 1 = very good. The median values were computed and a descriptive analysis performed. Interrater and intrarater agreement were expressed as weighted kappa.

RESULTS

The median values of both Scanora and Orthophos radiographs were the same, scoring 2. The intra- and inter-observer agreement was generally poor and similar for both machines.

CONCLUSIONS

The two panoramic machines were both given good ratings for evaluation of anatomical structures. The differences were very small and suggest that both machines are suitable for clinical use.
Radiological findings in an unusual osteosarcoma in the maxilla
Authors: Cavalcanti M G , Ruprecht A , Yang J
Published: October 2024

An unusual case of osteosarcoma of the maxilla, which was initially diagnosed as fibrous dysplasia on the basis of the clinical CT and histopathological findings, is presented. However, panoramic and periapical radiography suggested a malignant neoplasm. After surgery, the tumor was diagnosed histopathologically as a low-grade osteosarcoma. We conclude that panoramic and periapical radiographs are important adjuncts and should be included in any investigation of the jaws where CT scanning is unable to differentiate between osteosarcoma and fibrous dysplasia.
Parotid lymph node metastasis from adenocarcinoma of the urachus
Authors: Shimoyama T , Horie N , Yamada T , Ide F
Published: October 2024

The parotid gland and its lymph nodes are frequent sites of metastases from head and neck cancers. However, metastasis from a distant primary below the clavicle is unusual. These originate from a variety of sites, most commonly the lung, kidney and breast. A case of a 59-year-old woman with parotid lymph node metastasis from an adenocarcinoma of the urachus, diagnosed on the basis of two discrete periparotid masses on CT and the patient's history, is presented.
A study of the association between the prognosis of carcinoma of the mandibular gingiva and the pattern of bone destruction on computed tomography
Authors: Nakayama E , Yoshiura K , Yuasa K , Kanda S , Saitoh M , Kage W , Ikebe T , Ozeki S , Shinohara M
Published: October 2024

OBJECTIVE

To clarify whether the pattern of bone destruction seen on CT is more closely associated with the outcome of carcinoma of the mandibular gingiva than that derived from panoramic radiographs (PR).

METHOD

Axial bone window CT scans and PR of 62 patients with carcinoma of the mandibular gingiva were evaluated retrospectively by two oral radiologists for the pattern of bone destruction. Patterns were classified into the three types: erosive, invasive and mixed. The relationship between these patterns with each imaging modality and cumulative recurrence rate, cumulative metastasis rate and cumulative survival rate, calculated by the Kaplan-Meier method, were statistically analysed by the log rank test.

RESULTS

The pattern of bone destruction derived from CT was closely associated with the cumulative metastasis rate (P < 0.05), the cumulative recurrence rate and the cumulative survival rate. In contrast, the pattern of bone destruction based on the PR was not associated with the cumulative metastasis rate (P = 0.43), the cumulative recurrence rate (P = 0.44), or the cumulative survival rate (P = 0.5).

CONCLUSION

The prognosis of patients with carcinoma of the mandibular gingiva is more closely related to a classification derived from the pattern of bone destruction on CT rather than PR. However, the number of subjects investigated in this study was not large enough to confirm our conclusions statistically. Further studies by other investigators are therefore needed.
Flattening of the articular eminence correlates with progressive internal derangement of the temporomandibular joint
Authors: Kurita H , Ohtsuka A , Kobayashi H , Kurashina K
Published: October 2024

OBJECTIVES

To test the hypothesis that flattening of the slope of the articular eminence occurs with progressive internal derangement (ID) of the TMJ.

METHODS

MR images of 170 TMJs in 130 patients with proven disk displacement were studied. The correlation between the prevalence of a flattened articular eminence and radiological stage of ID was analysed.

RESULTS

The prevalence of a flattened articular eminence was significantly higher in the joints with advanced ID (Mann-Whitney's U-test, P < 0.05).

CONCLUSIONS

It appears that a flattening of the slope of the articular eminence occurs as a result of remodeling or degenerative changes secondary to ID.