Film and digital radiography for detection of simulated root resorption cavities

Soft tissue simulant materials in X-ray-based imaging in dentomaxillofacial radiology: a scoping review

INTRODUCTION

In in-vitro dental radiographic research, simulation of soft tissue is required to replicate the clinical condition as close as possible. This study aimed to find out which soft tissue simulation material have been studied to use in dentomaxillofacial radiology and showed similarity in radiodensity to the soft tissues of the maxillofacial region.

METHODS

In this scoping review, Web of Science, Embase, Scopus, Google scholar and PubMed databases were searched on April 9, 2023, considering the following PICOS: Population: soft tissue simulants, Intervention: X-ray-based imaging, Comparison: -, Outcome: properties of the soft tissue simulants, Study design: in-vitro studies. Screening, study selection, and data extraction were performed by two independent researchers. A third team member was consulted in the case of disagreement. Quality assessment of the included studies was made using Quality Assessment Tool For In-Vitro Studies (QUIN Tool).

RESULTS

Of the initial 1172 articles retrieved in the database search, 13 studies were included in the review. Seven studies had a low risk of bias. In 8 studies, computed tomography (CT) or cone beam computed tomography (CBCT), in 4 studies intraoral radiography, and in 2 studies panoramic radiography was used (one study has used CT/CBCT and panoramic radiography). The studies varied in the radiographic modality, acquisition parameters, selected outcomes, and gold standard. In the majority of the studies (n = 10, 77%), acrylic resin derivatives were used in the soft tissue simulant formula alone or as a major component. Wax was used in the simulant material in 8 studies (62%). In addition, in 3 studies (23%) ice/water was used as the main simulant.

CONCLUSION

Ballistic gelatin, expanded 2-cm thick polystyrene with or without 1-cm utility wax, and 0.5 cm of acrylic resin were shown to have a radiographic density similar to soft tissue in standardized studies employing CBCT scanning. For intraoral radiographs, using self-polymerizing acrylic resin, utility wax, and wood, as well as a polymethylmethacrylate box filled with water in thicknesses ranging from 4 to 45 mm, provides suitable radiographic contrast. However, for 4 and 8 mm of wax and 4 mm of water, the radiographic contrast is not appropriate. In addition, 13-17 mm wax and 14.5 mm acrylic resin showed acceptable soft tissue densities in intraoral radiography. Further studies using different imaging modalities with standardized conditions and objective metrics are required to confirm the most appropriate soft tissue simulant material for in-vitro dental radiographic research.

Comparison of Efficiency and Image Quality of Photostimulable Phosphor Plate and Charge-Coupled Device Receptors in Dental Radiography

The photostimulable phosphor (PSP) plate and charge-coupled device (CCD) are receptors commonly used for intraoral radiography in U.S. dental schools. However, it is unclear which receptor is more beneficial for radiology education and patient care in an academic setting. The aim of this study was to compare the time efficiency, image quality, and operator performance for student-operated PSP plate and CCD receptors. At one U.S. dental school in 2018, 20 dental hygiene and dental students (n=10 each) were recruited as operators. They each exposed anterior and posterior periapical and bitewing radiographs on dental radiograph teaching and training replica using the PSP plate and CCD as receptors. The time taken to expose the radiographs was recorded. Image sharpness/definition, brightness/contrast, and technical errors, including placement, angulation, and cone cut errors, were evaluated on a three-point scale with 0=non-diagnostic, 1=diagnostic acceptable with minor errors, and 2=perfect diagnostic quality. The results showed that it was generally faster for the students to expose intraoral radiographs with CCDs than with PSP plates, although the difference was not significant (p>0.05). Image quality and technical accuracy, especially angulation, were significantly superior for PSP relative to CCD (p<0.05). This study found that PSP imaging was of higher quality and accuracy than CCD, whereas CCD was more efficient. Dental and dental hygiene students would benefit from being trained on both receptors to be able to adapt to a diversified workplace.

Root Resorption in Orthodontics

Root resorption has been the subject of many studies, and it can be caused by many factors such as the mechanics used during orthodontic treatment, factors related to the type and magnitude of the force, and other factors related to treatment such as the type of tooth movement and malocclusion. The clinical importance of root resorption is directly related to its detectability. Therefore, orthodontic and biological factors that may cause root resorption were evaluated using various imaging methods in present use. In this review, root resorption in orthodontics was considered from different viewpoints.

Effect of Voxel Size on Detection of External Root Resorption Defects Using Cone Beam Computed Tomography

BACKGROUND

Selecting a voxel size that yields minimal radiation dose with no significant compromise of the diagnostic accuracy of cone beam computed tomography (CBCT) is particularly important.

OBJECTIVES

This study aimed to assess the effect of voxel size on detection accuracy of simulated external root resorption defects using NewTom CBCT system.

MATERIALS AND METHODS

In this diagnostic study, the roots of 90 extracted human central incisors were hypothetically divided into cervical, middle, and apical thirds. Variable-size defects were prepared in the buccal and lingual surfaces of the roots and CBCT scans were obtained with four different voxel sizes (150, 200, 250, and 300). Presence or absence of defects on CBCT scans was determined by three radiologists and the results were compared with the gold standard (actual size and depth of defects). Sensitivity and specificity values were calculated and reported for different groups.

RESULTS

In the lingual surfaces, the highest specificity and sensitivity belonged to 300µm voxel size (92.9%), and 200 and 250µm voxel sizes (both 97.4%) in the cervical third, respectively. In the middle third, the highest specificity and sensitivity belonged to 250 and 200µm voxel sizes (84.6% and 100%, respectively). In the apical third, the highest specificity and sensitivity belonged to 300 µm voxel size (100% and 97.9%, respectively). In the buccal surfaces, the highest specificity and sensitivity belonged to 150 (75.0%), 300 and 250 µm voxel sizes (100%) and the minimum values belonged to 200 µm voxel size (60% and 97.3%) in the cervical third. In the apical third, the highest specificity and sensitivity were noted in 300 µm voxel size (100% and 97.6%, respectively) and the minimum values were seen in 200 and 150 µm voxel sizes (93.8%, 90.5%, respectively). In the middle third, 300, 250 and 200 µm voxel sizes yielded the highest specificity (88.9%), while 150 µm voxel size yielded the highest sensitivity (98.8%).

CONCLUSION

Considering the similar diagnostic efficacy of all voxel sizes, 300 µm voxel size can be used with adequate efficacy for detection of external root resorption defects with minimal patient radiation dose and the shortest scanning time.

Diagnostic Accuracy of Cone-Beam Computed Tomography and Periapical Radiography in Internal Root Resorption

INTRODUCTION

The aim of this study was to compare the diagnostic value of cone-beam computed tomography (CBCT) and periapical (PA) radiography in detecting internal root resorption.

METHODS AND MATERIALS

Eighty single rooted human teeth with visible pulps in PA radiography were split mesiodistally along the coronal plane. Internal resorption like lesions were created in three areas (cervical, middle and apical) in labial wall of the canals in different diameters. PA radiography and CBCT images were taken from each tooth. Two observers examined the radiographs and CBCT images to evaluate the presence of resorption cavities. The data were statistically analyzed and degree of agreement was calculated using Cohen's kappa (k) values.

RESULTS

The mean±SD of agreement coefficient of kappa between the two observers of the CBCT images was calculated to be 0.681±0.047. The coefficients for the direct, mesial and distal PA radiography were 0.405±0.059, 0.421±0.060 and 0.432±0.056, respectively (P=0.001). The differences in the diagnostic accuracy of resorption of different sizes were statistically significant (P<0.05); however, the PA radiography and CBCT, had no statistically significant differences in detection of internal resorption lesions in the cervical, middle and apical regions.

CONCLUSION

Though, CBCT has a higher sensitivity, specificity, positive predictive value and negative predictive value in comparison with conventional radiography, this difference was not significant.

Comparison of intraoral radiography and cone-beam computed tomography for the detection of periodontal defects: an in vitro study

Background

This study aimed to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) unit with digital intraoral radiography technique for detecting periodontal defects.

Methods

The study material comprised 12 dry skulls with maxilla and mandible. Artificial defects (dehiscence, tunnel, and fenestration) were created on anterior, premolar and molar teeth separately using burs. In total 14 dehiscences, 13 fenestrations, eight tunnel and 16 without periodontal defect were used in the study. These were randomly created on dry skulls. Each teeth with and without defects were images at various vertical angles using each of the following modalities: a Planmeca Promax Cone Beam CT and a Digora photostimulable phosphor plates. Specificity and sensitivity for assessing periodontal defects by each radiographic technique were calculated. Chi-square statistics were used to evaluate differences between modalities. Kappa statistics assessed the agreement between observers. Results were considered significant at P < 0.05.

Results

The kappa values for inter-observer agreement between observers ranged between 0.78 and 0.96 for the CBCT, and 0.43 and 0.72 of intraoral images. The Kappa values for detecting defects on anterior teeth was the least, following premolar and molar teeth both CBCT and intraoral imaging.

Conclusions

CBCT has the highest sensitivity and diagnostic accuracy for detecting various periodontal defects among the radiographic modalities examined.

Diagnostic Accuracy of Charge-coupled Device Sensor and Photostimulable Phosphor Plate Receptor in the Detection of External Root Resorption In Vitro

Background and aims. Early diagnosis of external root resorption is important for accurate treatment. The purpose of this study was to compare the efficacy of a charge-coupled device (CCD) sensor and a photostimulable phosphor (PSP) plate receptor in the diagnosis of artificial external root resorption.

Materials and methods. In this diagnostic in-vitro study, 40 maxillary incisors were mounted in a segment of dry bone and preliminary radiographs were obtained using CCD and PSP sensors. Artificial resorption cavities were produced on the middle-third in half of the samples and on the cervical-third in the other half on the buccal root surfaces. Radiographs were repeated and images were evaluated. Data were statistically analyzed using chi-square and diagnostic tests.

Results. There were no significant differences between the two sensors in the sensitivity (p=0.08 and 0.06) and specificity (p=0.13) for the diagnosis of resorption in both root areas. The overall accuracy of CCD was higher than PSP sensor; however, the difference was not statistically significance (p>0.05).

Conclusion. CCD and PSP sensors chosen for the present study produced similar results in diagnosing simulated external root resorption.

Film and digital periapical radiographs for the measurement of apical root shortening

Objectives: The aim of this study was to compare the accuracy and agreement of scanned film and digital periapical radiographs for the measurement of apical root shortening. Study design: Twenty-four film and digital [phosphor plate sensor (PPS)] periapical radiographs were taken using the long-cone paralleling technique for six extracted teeth before and after 1mm of apical root trimming. All teeth were mounted using a typodont and the radiographs were recorded using a film holder and polysiloxane occlusal index for each tooth to ensure standardization during the different radiographic exposures. The film radiographs were scanned and the tooth length measurements for the scanned film and digital (PPS) images were calculated using Image-J-Link 1.4 software (http://rebweb.nih.gov/ij/index.html) for the two groups. The accuracy and agreement among the tooth length measurements from each group and the true tooth length measurements were calculated using intra-class correlation (ICC) tests and Bland and Altman plots. Results: A high level of agreement was found between the true tooth length measurements and the scanned film measurements (ICC=0.979, limit of agreement 0.579 to -0.565) and the digital (PPS) radiograph measurements (ICC= 0.979, limit of agreement 0.596 to -0.763). Moreover, a high level of agreement was found between the scanned film and digital (PPS) radiographs for the measurement of tooth length ICC=0.991, limit of agreement 0.411-0.231. Conclusion: Film and digital (PPS) periapical radiographs are accurate methods for measuring apical root shortening with a high level of agreement.

Key words:Root shortening, measurement, periapical radiographs, film, digital.

Validity of wax and acrylic as soft-tissue simulation materials used in in vitro radiographic studies

OBJECTIVE

To determine the thickness of wax and acrylic that provides a radiographic density similar to that of the human cheek.

METHODS

An intraoral film radiograph of the human cheek including a 40×30×3 mm reference aluminium block was recorded under standardized conditions in 61 subjects. Radiographic density was measured by a densitometer in ten randomly selected sites of the film to serve as the gold standard for density values of the cheek soft tissues. Thereafter, the density of series of radiographs of two tissue-simulating materials-wax and acrylic-in systematically increasing thicknesses (wax, 1.5-30 mm; acrylic, 2-40 mm) plus the reference block were measured and compared with the gold-standard values.

RESULTS

The radiographic density of wax with a thickness of 13-17 mm or acrylic with a thickness of 14.5 mm corresponded to the average density of the human cheek.

CONCLUSION

The soft tissues of the average human cheek can be simulated with 13-17 mm wax or 14.5 mm acrylic in in vitro radiographic studies.

Diagnostic value of two modes of cone-beam computed tomography in evaluation of simulated external root resorption: an in vitro study

PURPOSE

Field of view and voxel resolution of cone beam computed tomography (CBCT) might affect the diagnostic capability. This study was performed to compare between the standard and HiRes zoom modes in the diagnosis of external root resorption (ERR) using CBCT.

MATERIALS AND METHODS

Sixty three small cavities (0.25 mm depth and 0.5 mm diameter) were simulated on the buccal, lingual, and proximal surfaces at three different levels of 16 roots of teeth. After covering the root with nail varnish, the roots were inserted in the sockets and the model was placed in a water-containing lacuna. CBCT scans were taken in both standard and HiRes zoom modes using NewTom VG (QR srl Company, Verona, Italy). Then, an observer assessed the images to determine the presence or absence of the cavities. This process was repeated by increasing the size and depth of cavities to 0.5 mm depth and 1 mm diameter. Data were analyzed by McNemar test. The sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio in evaluation of the simulated cavities were calculated.

RESULTS

There was a significant difference between the two imaging modes in diagnosing the shallow cavities (p=0.02).The sensitivity of the standard zoom in detecting the shallow cavities was lower than that of the HiRes zoom. The likelihood ratio of the HiRes zoom was higher in the diagnosis of both cavity types.

CONCLUSION

This study suggested that a smaller voxel size in the HiRes zoom mode of CBCT is preferred for diagnosis of ERR.

Comparison of 6 cone-beam computed tomography systems for image quality and detection of simulated canine impaction-induced external root resorption in maxillary lateral incisors

INTRODUCTION

The most frequent adverse effect of canine impaction is resorption of the adjacent incisors. The subjective image quality and the radiographic diagnostic accuracy for detection of simulated canine-induced external root resorption lesions in maxillary lateral incisors were compared among 6 cone-beam computed tomography (CBCT) systems in vitro.

METHODS

A child cadaver skull in the early mixed dentition was obtained. This skull had an impacted maxillary left canine and allowed a reliable simulation. Simulated root resorption cavities were created in 8 extracted maxillary left lateral incisors by the sequential use of 0.16-mm diameter round burs in the distopalatal root surface. Cavities of varying depths were drilled in the middle or apical thirds of each tooth root according to 3 setups: slight (0.15, 0.20, and 0.30 mm), moderate (0.60 and 1.00 mm), and severe (1.50, 2.00, and 3.00 mm) resorption. The lateral incisors, including 2 intact teeth, were repositioned individually in the alveolus with approximal contacts to the impacted maxillary left canine. Six sets of radiographic images were obtained with 3D Accuitomo-XYZ Slice View Tomograph (J. Morita, Kyoto, Japan), Scanora 3D CBCT (Soredex, Tuusula, Finland), Galileos 3D Comfort (Sirona Dental Systems, Bensheim, Germany), Picasso Trio (E-WOO Technology, Giheung-gu, Republic of Korea), ProMax 3D (Planmeca OY, Helsinki, Finland), and Kodak 9000 3D (Trophy, Croissy-Beaubourg, France) for each tooth setup. The CBCT images were acquired and subsequently analyzed by 12 observers. Linear models for repeated measures were used to compare the CBCT systems for the image quality and the degree of agreement between the diagnosed severity of root resorption and the true severity.

RESULTS

The differences in the image quality between CBCT systems were statistically significant (P <0.001). The root resorption scores between CBCT systems showed a significantly higher score for the ProMax when compared with the Galileos and the Kodak. However, the differences in agreement between the diagnosed severity of root resorption and the true severity for all resorption sizes were not significantly different (P >0.05) among the different CBCT systems.

CONCLUSIONS

High image quality is important when detecting root resorption. The CBCT systems used in this study had high accuracy with no significant differences between them in the detection of the severity of root resorption.

Comparison between cone-beam computed tomography and intraoral digital radiography for assessment of tooth root lesions

INTRODUCTION

Cone-beam computed tomography (CBCT) might be more accurate in identifying radicular surface lesions compared with digital periapical radiography. In this study, we compared these techniques in detecting simulated root resorption lesions.

METHODS

A porcine mandible was used to support 10 human maxillary central incisors. CBCT and digital periapical radiographic images were generated before and after the introduction of standardized and sequentially larger root defects on either the mesial or the lingual root surfaces. The images were randomly labeled and evaluated by 3 examiners. Each image was classified according to defect size (0, none; 1, mild; 2, moderate; 3, severe).

RESULTS

Interrater reliability was acceptable (0.856 ≤ P ≤ 0.981). The location of the root defect (mesial vs lingual) had no significant effect on the evaluation of defect size. Both periapical radiographs and CBCT were slightly better at detecting lingual defects than mesial defects (75% vs 65% and 65% vs 60%, respectively), but these effects were not statistically significant (P = 0.49 and P = 0.74, respectively). The mean percentages of correctly diagnosed defect sizes were 65% for CBCT and 75% for periapical radiographs. Examiners using CBCT images tended to overestimate defect sizes (κ = 0.481) and correctly categorized teeth with no, mild-moderate, and severe defects 80%, 45%, and 90% of the time, respectively. Examiners using periapical radiographs tended to underestimate defect sizes (κ = 0.636) and categorized teeth with no, mild-moderate, and severe defects 100%, 50%, and 100% of the time, respectively.

CONCLUSIONS

There was no difference in accuracy of identifying defects between periapical radiographs and CBCT images.

Comparison between two tomographic sections in the diagnosis of external root resorption

Objectives

To assess the accuracy of coronal and sagittal CT sections to detect cavities simulating root resorption.

Material and Methods

60 mandibular incisors were embedded in plaster bases, and cavities with 0.6, 1.2 or 1.8 mm in diameter and 0.3, 0.6 or 0.9 mm in depth (small, medium and large cavities) were drilled on the buccal surfaces with high-speed round burs with diameters of 0.6, 1.2 and 1.8 mm to simulate external inflammatory root resorption. Simulations in the cervical, middle and apical thirds of each tooth root were made randomly. The Dental Scan software was used to obtain 1-mm-thick axial images from direct scanning, which were reconstructed in the coronal and sagittal planes using 3D software (Syngo FastView). Each series was loaded into the software. Fourteen images of each tooth were reconstructed in the coronal plane and 14 in the sagittal plane. A total of 1,652 images were obtained for analysis. Series information, tooth number and the plane reconstructed were stored. The images generated were saved on a CD-ROM together with the visualization software (Syngo FastView). Images were analyzed by a previously calibrated blinded, radiologist. Cochran’s Q test was conducted separately for each region analyzed followed by pair-wise comparison by the McNemar test (p=0.05).

Results

No statistically significant difference (p>0.05) was observed in the diagnosis of simulated resorption between the apical, middle, and coronal thirds. When the axial plane was assessed separately, diagnoses were statistically different (p<0.05) among the three root thirds. The apical third differed significantly (p<0.05) from the cervical and middle thirds. Diagnostic errors were more often observed in the apical third compared to the cervical and middle thirds. Mid-sized cavities revealed no statistically significant differences (p>0.05) between planes, irrespective of the third in which the resorptions were located.

Conclusion

When tomographic sections are requested for the diagnosis of buccal or lingual external root resorption, sagittal sections afford the best image characterization of the resorption process.

Comparative evaluation among different materials to replace soft tissue in oral radiology studies

Objective

The aim of this study was to establish which materials afford better simulation of soft tissues in Oral Radiology studies.

Material and Methods

The sample was composed of four materials in eleven different thicknesses to simulate the soft tissues of the face. The mean values of the relative amounts of radiographic contrast of the materials were determined and compared to a gold standard value, which was obtained from 20 patients who were referred to have periapical radiographs taken of the left mandibular molars. Data were subjected to statistical analysis with Dunnett's test (p<0.05).

Results

The mean value of the relative amounts of contrast encountered in the patients was 0.47, with a range between 0.36 and 0.64 for all 44 material/thickness combinations. The majority of the tested materials showed values close to those of the patients’ tissues, without statistically significant differences among them. The values of only three materials/ thickness combinations differed statistically from those of the patients’ tissues.

Conclusions

Based on the results of the present study, it may be concluded that except for utility wax (4 mm and 8 mm) and water (4 mm), all materials tested at different thickness could be used as soft tissue substitute materials in Oral Radiology studies.

The detection and management of root resorption lesions using intraoral radiography and cone beam computed tomography - an in vivo investigation

AIM

To compare the accuracy of intraoral periapical radiography with cone beam computed tomography (CBCT) for the detection and management of resorption lesions.

METHODOLOGY

Digital intraoral radiographs and CBCT scans were taken of patients with internal resorption (n = 5), external cervical resorption (n = 5) and no resorption (controls) (n = 5). A 'reference standard' diagnosis and treatment plan was devised for each tooth. Sensitivity, specificity, positive predictive values, negative predictive values and receiver operator characteristic (ROC) curves, as well as the reproducibility of each technique were determined for diagnostic accuracy and treatment option chosen.

RESULTS

The intraoral radiography ROC Az values were 0.780 and 0.830 for diagnostic accuracy of internal and external cervical resorption respectively. The CBCT ROC Az values were 1.000 for both internal and external cervical resorption. There was a significantly higher prevalence (P = 0.028) for the correct treatment option being chosen with CBCT (%) compared with intraoral radiographs (%).

CONCLUSION

CBCT was effective and reliable in detecting the presence of resorption lesions. Although digital intraoral radiography resulted in an acceptable level of accuracy, the superior accuracy of CBCT may result in a review of the radiographic techniques used for assessing the type of resorption lesion present. CBCT's superior diagnostic accuracy also resulted in an increased likelihood of correct management of resorption lesions.

Influence of voxel size in the diagnostic ability of cone beam tomography to evaluate simulated external root resorption

This study assessed in vitro the diagnostic ability of cone beam computed tomography (CBCT) scans with different voxel resolutions in the detection of simulated external root resorption (ERR). For that purpose, 59 teeth were viewed through iCAT tomography (Imaging Sciences International, Inc, Hatfield, PA) following three protocols in which the variation was the voxel resolution (0.4, 0.3, and 0.2mm). A calibrated examiner blinded to the protocol assessed the images through the i-CAT View software (Imaging Sciences International, Inc). The chi-square statistical analysis did not show associations between voxel resolution, section plane, size of cavity, and radicular third. Sensitivity and specificity values were similar. However, likelihood ratio values of 6.4 for a 0.4-mm voxel, 16 for a 0.3-mm voxel, and 12 for a 0.2-mm voxel were found. It was concluded that CBCT is a reliable method for the investigation of simulated ERR, and a 0.3-mm voxel appeared to be the best protocol, associating good diagnostic performance with lower X-ray exposure.

Detection of artificial occlusal caries in a phosphor imaging plate system with two types of LCD monitors versus three different films

The aim of this study was to determine diagnostic performance of a storage phosphor plate system Digora Optime (Soredex, Helsinki, Finland) with two types of LCD monitor in the detection of artificial caries when compared to Ultraspeed (D), Ektaspeed Plus (E), and Insight (F) radiographic films. Seventy extracted human molars-with artificial caries-were radiographed under identical standardized conditions using (1) a storage phosphor plate system Digora (Soredex, Helsinki, Finland), (2) Insight, (3) Ektaspeed Plus, and (4) Ultraspeed (Carestream Health Inc, Rochester, NY). All digital images and radiographs were examined by three observers for the presence or absence of artificial caries using a five-point confidence scale. Digital images were evaluated both on a LCD computer monitor (Philips 170S, Holland) and medical monitor-3 megapixel monochrome display (Me355i2, Totoku, Tokyo)-with brightness and contrast enhancement. Observer responses were evaluated using ROC analysis and other measurements for diagnostic accuracy. Storage phosphor images with medical monitor demonstrated higher mean A (z) values (0.70 +/- 0.08) than digital images with computer monitor and conventional films. Storage phosphor images with medical monitor presented the highest score, 0.97, 0.90, 0.94, for each observer, respectively. Also, true positive observations (0.82) and positive likelihood ratios (2.71) were higher in enhanced storage phosphor images with medical monitor. Caries detection of mechanically created lesions by experienced radiologists is roughly comparable when examining D-speed film images and Digora images on both the computer and medical LCD monitors, and appears to be poorer on E- and F-speed film images.

Detection and size differentiation of simulated tooth root defects using flat-panel volume computerized tomography (fpVCT)

OBJECTIVE

Our aim was to evaluate the capacity of flat-panel volume computerized tomography (fpVCT) to enable the observer to detect and differentiate 3 different sizes of simulated tooth root defects in radiographs.

STUDY DESIGN

Three simulated tooth root defects of different sizes and a defect-free area (160 sites in total) were randomly distributed on the buccal and lingual surface of 20 mandibular premolar roots of Sus scrofa domestica with round burs. For the imaging of the specimens, an fpVCT prototype was used. Findings were evaluated by 3 observers.

RESULTS

Cavity 0 (no lesion) was correctly identified in 53%, cavity 1 in 69%, cavity 2 in 96%, and cavity 3 in 89%. Altogether, the simulated cavities were classified in a correct manner in 77%. The values were compared using receiver operating characteristic curves. The area under the curve (AUC) for cavity 0 versus the pooled results for cavities 1-3 was found to be 0.72. The AUC for the pooled results for 0-2 (no pathologic impact) versus cavity 3 (potential pathologic impact) was 0.94. There was no significant dependence of the results on the observer (P = .37). Results with P < .05 were considered to be significant.

CONCLUSIONS

Flat-panel volume computerized tomography, which is currently used only as a research tool, has a high potential in detection and differentiation at an early stage of external root resorption cavities with pathologic relevance..

Diagnosis of artificially induced external root resorption using conventional intraoral film radiography, CCD, and PSP: an ex vivo study

OBJECTIVE

To compare diagnosis of artificially induced external root resorption cavities using conventional intraoral film radiography (Kodak Insight), CCD sensor (Sopix wireless) and PSP sensor (Orex Digident).

STUDY DESIGN

Two mandibles were obtained from cadavers and teeth extracted from their alveolus. Artificial external root resorptions were simulated using ISO 0.5 mm, 0.8 mm, and 1.2 mm diameter round burs by drilling to the entire depth in different locations at the cervical, middle, and apical thirds of the proximal and buccal root surfaces of 6 teeth in increasing order. Conventional and digital radiographs were obtained from 3 different views of each tooth in 3 steps (small = 0.5 mm; medium = 0.8 mm; and large = 1.2 mm diameter round burs). Three observers examined all images for the presence of resorption cavities. In the first session, each image was evaluated separately; in the second, examiners had access to all views. Data were statistically analyzed using 4-way analysis of variance. Pair-wise comparison between receptors, projection views, size, and location were made by Tukey test.

RESULTS

Higher proportions of correct readings were obtained with the conventional film (Kodak Insight) and CCD receptor compared with the PSP receptor used in this study (PSP < CCD <or= Film; P < .001). Best results were obtained when examiners had access to all views. Most difficult locations in determining true diagnosis were the apical regions. Highest correct readings were obtained at the proximal cervical regions.

CONCLUSION

Conventional intraoral film and CCD sensor produced similar results in diagnosing simulated external root resorption.

Diagnostic ability of computed tomography to evaluate external root resorption in vitro

OBJECTIVES

The aim of this study was to evaluate the diagnostic ability of CT to detect simulated external root resorption defects.

METHODS

External root resorption defects of different sizes and in different locations were simulated in 59 human mandibular incisors. Cavities simulating root resorption defects of 0.6 mm, 1.2 mm, or 1.8 mm in diameter and 0.3 mm, 0.6 mm, or 0.9 mm in depth (small, medium and large defects) were drilled in the cervical, middle and apical thirds of buccal surfaces. Axial CT was used to obtain cross-sectional images of the teeth, and 177 root thirds were assessed by a blinded observer.

RESULTS

Of the 131 cavities, 117 were detected (89%). 32 of the 44 (72.72%) cavities located in the apical third were identified. A statistically significant difference (P<0.01) was found between the sizes of defects examined in the apical third.

CONCLUSIONS

The evaluation of CT diagnostic ability revealed high sensitivity and excellent specificity. However, small cavities located in the apical third were more difficult to detect than all other cavities.

Comparison of conventional film with different digital and digitally filtered images in the detection of simulated internal resorption cavities--an ex vivo study in human cadaver jaws

OBJECTIVE

To determine observers' ability to detect experimentally induced simulated internal resorption cavities using conventional film, digital images and digitally filtered images.

STUDY DESIGN

In the coronal plane, 11 single-rooted teeth with radiographically visible pulps were split in half. Four artificial internal resorptions were simulated in each tooth at the coronal, cervical, mid-root, and apical locations of the buccal/labial wall. Conventional and digital radiographs were taken from 3 different views in 4 steps. Three observers examined conventional, digital, and digitally filtered images for the presence of resorption cavities. Data were statistically analyzed using analysis of variance. Pair-wise comparison between receptors, location, and size were made by Tukey post hoc test.

RESULTS

One digital system produced a significantly lower proportion of correct readings, with no significant difference between other imaging types (P < .001). In the apical region, internal resorption was the most difficult to detect. The cervical region had the highest proportion of correct readings (P < .001). False-positive readings were higher in the apical and mid-root locations (P < .001). Defect size increased detection ability. Interaction was significant between receptor and size and between size and location (P < .001).

CONCLUSIONS

All systems, except PSP, produced similar results in detecting simulated internal resorption.

Quantitative determination of radio-opacity: equivalence of digital and film X-ray systems

OBJECTIVES

To evaluate the equivalence of a digital X-ray system (DenOptix) to conventional X-ray film in terms of the measured radio-opacity of known filled-resin materials and the suitability of attenuation coefficient for radio-opacity determination.

METHODS

Discs of five thicknesses (0.5-2.5mm) and step-wedges of each of three composite materials of nominal aluminum-equivalence of 50%, 200% and 450% were used. X-ray images of a set of discs (or step-wedge), an aluminum step-wedge, and a lead block were taken at 65 kV and 10 mA at a focus-film distance of 400 mm for 0.15s and 1.6s using an X-ray film or imaging plate. Radio-opacity was determined as equivalent aluminum thickness and attenuation coefficient. The logarithm of the individual optical density or gray scale value, corrected for background, was plotted against thickness, and the attenuation coefficient determined from the slope. The method of ISO 4049 was used for equivalent aluminum thickness.

RESULTS

The equivalent aluminum thickness method is not suitable for materials of low radio-opacity, while the attenuation coefficient method could be used for all without difficulty. The digital system gave attenuation coefficients of greater precision than did film, but the use of automatic gain control (AGC) distorted the outcome unusably.

CONCLUSION

Attenuation coefficient is a more precise and generally applicable approach to the determination of radio-opacity. The digital system was equivalent to film but with less noise. The use of AGC is inappropriate for such determinations.

Radiographic evaluation and treatment of feline dental resorptive lesions

Many feline resorptive lesions are easily diagnosed by clinical oral examination, whereas others require dental radiographs. Radiographs can reveal the presence of resorption, and often the nature of the resorptive process as well. Removal of affected teeth when they cause discomfort, or of the portion of the tooth causing the discomfort, remains the only treatment that provides long-term resolution. Until we understand the etiology of the inciting causes and of the factors contributing to the progression of resorptive lesions, reliable prevention cannot be offered.

Conventional and digital radiographic methods in the detection of simulated external root resorptions: a comparative study

OBJECTIVES

The purpose of this study was to evaluate and to compare the efficacy of a conventional and a digital radiographic method in diagnosing simulated external root resorption cavities.

METHODS

Human dry mandibles containing teeth were covered with bovine muscle slices in order to simulate the soft tissues. Nine teeth from each dental group were investigated. Three periapical radiographs of each tooth were taken in an orthoradial, mesioradial and distoradial aspect using conventional film (Insight Kodak F-speed; Eastman Kodak, Rochester, NY) and a digital sensor (DRS Gnatus System; Gnatus, Ribeirao Preto, Brasil). The teeth were extracted using a forceps and had 0.7 mm and 1.0 mm deep cavities prepared on their vestibular, mesial and distal surfaces at the cervical, middle and apical thirds. Following preparation, each tooth was replaced in its alveolus and new radiographs were taken. Three dental professionals, an endodontist, a radiologist and a general practioner, evaluated the images.

RESULTS

A larger number of cavities (P<0.05) were detected by the digital method when compared with the conventional method, for all depths of lesions.

CONCLUSIONS

The results of this study suggest that the digital radiographic method is more sensitive than conventional radiography to detect simulated external root resorption cavities.

Exploring the third dimension in root resorption

OBJECTIVE

To review and investigate the validity of various 2D quantitative measurement techniques, and to explore the third dimension of root resorption.

DESIGN

A review of the literature involving various quantitative evaluation of root resorption.

RESULTS

Quantitative evaluation of resorption using radiographs has proven to be highly inaccurate because of magnification errors and their inability to be readily repeated and reproduced. Studies using histology sections of samples have proven to be laborious and technique sensitive. Inherent parallax errors and loss of material in data transfer have denied the true understanding of this 3D event.

CONCLUSION

With the evolution in computing technology and digital imaging, the vision of evaluating the extent of root resorption in 3D has materialized. It was demonstrated that 3D volumetric quantitative evaluation of root resorption craters was feasible and its accuracy and repeatability was high.

The dynamic range of digital radiographic systems: dose reduction or risk of overexposure?

OBJECTIVES

To investigate the range of diagnostically acceptable digital radiographs and film as a function of exposure time, as well as the relationship to dose reduction and consequences for dental practice.

METHODS

Five systems for intraoral radiography were used to take a series of radiographs, with increasing exposure times, of five different dry bone specimens. Seven observers evaluated the 25 series of radiographs. The observers had to determine which radiographs of each series were acceptable for dental diagnostics and which radiograph of each series they preferred.

RESULTS

For Ektaspeed Plus film, the exposure time for the preferred radiograph was 0.52 s, with a range of diagnostically acceptable radiographs from 0.23-1.02 s. The preferred radiograph of the solid-state systems required less radiation than film (Sirona, 0.13 s; MPDx 0.35 s). The exposure range of these systems is narrow. In contrast, the exposure range of the phosphor plate systems is very wide. The preferred radiograph of the phosphor plate systems required high exposure (Digora, 1.21 s; Gendex DenOptix, 1.16 s).

CONCLUSIONS

All digital systems require less exposure than film for diagnostically acceptable radiographs, but this is less obvious for preferred radiographs. Solid-state systems alert the dentist when a too long exposure time is used by a lack of image quality; phosphor plate systems, however, produce good quality radiographs even at high exposure times, which may result in an unnecessarily high dose.

A comparative evaluation of the diagnostic efficacy of film and digital sensors for detection of simulated periapical lesions

OBJECTIVE

The purpose of this study was to evaluate the diagnostic efficacy of Ektaspeed Plus film (EPF), a charge-coupled device (CCD), and photostimulable phosphor (PSP)-based digital images for detection of simulated periapical lesions.

STUDY DESIGN

Lesions were simulated in the periapical areas of 24 human mandibular sections invested in acrylic using burs of sizes #1, 2, 4, and 6 and imaged using EPF, CCD, and PSP sensors. Percent correct response scores, sensitivity, and specificity values were computed for all variables. Repeated-measures analysis of variance and post hoc testing were performed to determine the effects of imaging modality, observer, and lesion sizes with respect to lesion detection.

RESULTS

EPF displayed the highest sensitivity and specificity, followed by PSP and CCD images (P <.001). Percent correct score was the highest for 3 of 4 observers when EPF was used. Analysis of variance revealed significance (P <.001) with respect to all variables. Observers with experience in digital image-viewing performed better than those without such experience (P <.001). Intraobserver agreement was fair (kappa = 0.5).

CONCLUSIONS

EPF outperformed CCD and PSP images when observers could manipulate image characteristics.

Comparison between PAI and quantitative digital radiographic assessment of apical healing after endodontic treatment

OBJECTIVE

The purpose of this study was to compare both subjective (Periapical Index, PAI) and objective (densitometric) radiographic evaluation of healing after endodontic treatment for apical periodontitis.

STUDY DESIGN

Standardized radiographs of 103 teeth taken at baseline (immediately after endodontic treatment) and at 1, 4, 12, 26, and 52 weeks were evaluated. Consensus PAI scores obtained from 7 calibrated observers served as "true scores." Densitometric estimates of periapical status were obtained from digitized radiographs as the ratio of mean gray value of an area of radiolucency (AR) to an adjacent and similar-sized normal (N) area (AR/N). The selected regions of interest on baseline images were automatically superimposed on postoperative images. All estimates of change were measured with respect to baseline. The subtraction estimate was expressed as AR(S)-N(S). Linear regression was used to analyze longitudinal changes against baseline and to assess the relationship of PAI and AR/N and of change in PAI with respect to baseline and AR(S)-N(S).

RESULTS

Five hundred fifty-six PAI scores were generated, with 547 AR/N values and 444 subtraction estimates. PAI, AR/N, and AR(S)-N(S) demonstrated statistical significance for change (P < or = .05) starting at 12 weeks. PAI was significantly correlated with AR/N (P < .0001), as was CHPAI with AR(S)-N(S) (P < .024).

CONCLUSION

The PAI and 2 densitometric estimates (AR/N and AR(S)-N(S)) detected healing of apical periodontitis at 12 weeks after treatment. No difference could be observed among the methods.

Radiographic diagnosis of root resorption in relation to orthodontics

The literature regarding external root resorption in relation to orthodontics and its radiographic diagnosis is reviewed, including a summary of the more common radiographic techniques available. Sample cases are presented which demonstrate the need for good radiographic technique and an awareness of the limitations of certain radiographs. A provisional diagnosis of external root resorption may need to be confirmed by further radiographic views where appropriate.

Radiographic study of the maxillary canine tooth of four mesaticephalic cats

The radiopaque and radiolucent anatomical structures that are superimposed over the root of the maxillary canine tooth in mesaticephalic cats were identified on digital radiographs made at various angles. The vomer bone, the nasal bone, the palatine fissure, and the infraorbital foramen were not superimposed over the root of the canine tooth in the range of angles examined. Superimposition with the palatine sulcus (which is rarely visible clinically because of silhouetting of the soft tissues) only occurred at extreme horizontal (cross-sectional arc) angles. The second premolar tooth was superimposed at a cross-sectional angle of 80 degrees and 90 degrees. The structures of concern in the interpretation of radiographs of the maxillary canine tooth in mesaticephalic cats are the conchal crest, the line of conjunction between the vertical body of the maxilla and its palatine process, the incisivomaxillary canal (which is rarely visible on radiographic images), and the lachrymal canal. Because of their anatomical vicinity, the radiographic position of these structures relative to the maxillary canine tooth can only be minimally changed. It was not possible to identify an "ideal" angle to radiograph the maxillary canine tooth in these four mesaticephalic cats. However, an acceptable compromise between minimal distortion of the image and satisfactory visualization of the root was obtained with the radiographic beam (rostro-caudal rotation) angled at 80 degrees and the skull (rotation in cross-sectional arc) angled at 70 degrees.

Detection of caries with conventional digital imaging and tuned aperture computed tomography using CRT monitor and laptop displays

OBJECTIVE

The purpose of this study was to compare the diagnostic performance of conventional digital images and tuned aperture computed tomography (TACT) slices in caries detection through use of cathode-ray tube monitor and laptop displays.

STUDY DESIGN

Forty-two extracted posterior teeth were mounted and imaged with a direct digital radiography system. Conventional digital bitewing projections and TACT slices were acquired. Images were viewed on a high-resolution cathode-ray tube monitor and on an active-matrix laptop display. Eight observers assessed caries status of occlusal and proximal surfaces of the teeth using all combinations of image and display modality. Observers' assessments were compared with the results of histologic examination of tooth sections. Possible differences in receiver operating characteristic curve areas among displays, image modalities, observers, and surfaces were analyzed by means of analysis of variance.

RESULTS

There was no statistically significant difference between the diagnostic performances provided by the cathode-ray tube monitor and laptop displays in caries detection (P = .588). In addition, the performances of digital images and TACT slices were not significantly different (P = .843).

CONCLUSIONS

Modern active-matrix laptop displays provide diagnostic quality for caries detection comparable to that obtainable with cathode-ray tube monitors.