The role of direct intraoral sensors in the provision of endodontic services

Void detection in root fillings using intraoral analogue, intraoral digital and cone beam CT images

AIM

To compare void detection in root fillings using different radiographic imaging techniques: intraoral analogue, intraoral digital and cone beam CT (CBCT) images and to assess factors influencing small void detection.

METHODOLOGY

Two straight root canals in canine teeth were prepared. Calibrated steel wires of five different diameters (200, 300, 350, 500, 800 microm) were inserted respectively in the canal after the injection of a sealer. To simulate filling voids of known dimensions, the wires were removed after the sealer had set. Each sample was imaged, using a Minray X-ray tube (Soredex, Helsinki, Finland) at optimal clinical settings combined with Vistascan PSP (Dürr Dental, Bietigheim-Bissingen, Germany), Digora Optime PSP (Soredex), Sigma CCD (Instrumentarium, Tuusula, Finland) and E-speed films (Agfa-Gevaert, Mortsel, Belgium). The teeth were also imaged using CBCT (3D Accuitomo, Morita, Japan). A generalized mixed model and ANOVA analysis were used on the acquired data (Tukey-Kramer correction).

RESULTS

There was no evidence that the factor 'root level' affected void detection in root fillings. 'Void size' was a main determining factor as all voids larger than 300 microm were determined with all techniques. For the smaller voids, there were significant differences between the 5 imaging techniques at different void sizes and different root levels.

CONCLUSIONS

Void size and imaging technique were main determining factors. Voids larger than 300 mum were determined with all imaging techniques. For small void detection, all digital intraoral techniques performed better than intraoral analogue and CBCT images.

Imaging of root canal fillings: a comparison of subjective image quality between limited cone-beam CT, storage phosphor and film radiography

AIM

To compare the subjective quality of limited cone-beam computed tomography (LCBCT), storage phosphor plate (SPP) and F-speed film images for the evaluation of length and homogeneity of root fillings.

METHODOLOGY

Root canals of 17 extracted permanent mandibular incisor teeth were filled. With the teeth placed in their jaws, images were obtained with Accu-I-Tomo LCBCT, Digora Optime image plate system and F-speed film using exposure parameters yielding 'clinically' acceptable density and contrast. Three radiologists and three endodontists independently rated the quality of all images in respect to homogeneity and the length of root fillings using a 3-graded scale. Evaluations were undertaken in two sessions. In the first, the coronal LCBCT images were not included. In the second, both coronal and sagittal LCBCT images were rated along with F-speed film and SPP images.

RESULTS

were compared using the Friedman test (P < 0.05). Pair-wise comparisons of systems were completed using the Wilxocon signed-ranks test (P < 0.05). Kappa was used to measure interobserver agreement. Results Digora images were rated superior, consecutively followed by F-speed films and LCBCT images, for the evaluation of both homogeneity and length of root fillings in both the evaluation sessions (P < 0.05). Kappa ranged from slight to moderate for the length evaluation of root fillings and from poor to fair for the evaluation of homogeneity of root fillings.

CONCLUSION

Image quality of storage phosphor images was subjectively as good as conventional film images and superior to LCBCT images for the evaluation of both homogeneity and length of root fillings in single-rooted teeth.

Digital and Advanced Imaging in Endodontics: A Review

This review provides an overview of digital radiography as it exists, including advanced imaging such as computed tomography (CT), cone beam volumetric imaging, and micro-CT as relevant to the practice of endodontics. An evidence-based approach to adoption of different imaging technologies is included to assist the practitioner with the selection process of imaging modalities. Commonly used imaging terminology is introduced, as well as the advantages and disadvantages of image processing. New image reconstruction techniques have been introduced that provide information three-dimensionally to the clinician for routine endodontic and surgical treatment planning. The age of three-dimensional imaging and image processing is here. Limitations and advantages of newly introduced imaging modalities are discussed briefly.

Comparison of standard and task-specific enhancement of Digora storage phosphor images for approximal caries diagnosis

OBJECTIVES

To compare approximal caries detection on Digora storage phosphor images pre-enhanced with the automatic "caries-specific Oslo enhancement procedure" ("Oslo-enhanced" method) and storage phosphor images individually enhanced by observers particularly experienced in digital imaging using standard brightness and contrast functions of the Digora system ("Digora-enhanced" method).

METHODS

Seven staff members from four oral radiology departments rated 240 approximal surfaces for caries with regard to lesion depth in the inner and outer half of the enamel and dentine, using a 5-point confidence scale. The observations were validated histologically. A receiver operating characteristic (ROC) analysis and an analysis of variance with three dependent variables (observer confidence, observer signed error and observer absolute error) were performed.

RESULTS

The most evident difference between the methods as elucidated by the ROC analysis was the highly significant smaller interobserver and intraobserver variance with the Oslo-enhanced method for all but one observer. The methods were not different with regard to average diagnostic accuracy (A(z) values) as tested with paired t-tests, and there was no correlation between A(z) across methods. The method and lesion main effects, as well as the lesion by method interaction effect, were multivariately significant (P<0.001) in favour of the Oslo-enhanced method. On a univariate level, the method main effect was not significant for the absolute observer error (P=0.330). All other univariate effects were significant (P<0.001).

CONCLUSIONS

The accuracy of approximal caries detection with Digora storage phosphor images pre-enhanced and images individually enhanced was similar, but interobserver and intraobserver variability improved with the Oslo-enhanced method. Since image manipulation is not performed with the Oslo-enhanced method, the increased speed of the diagnostic procedure combined with the improved observer variability would probably be even more pronounced for the general dental practitioner.

Fraudulent management of digital endodontic images

AIM

To present examples of radiographic image reconstructions in endodontic treatment, to discuss the potential problems arising from the use of image processing software and to mention some current methods to prevent such counterfeit utilization of digital endodontic radiographs.

SUMMARY

Conventional Ultra-Speed periapical films of root canal treatment were digitized with flatbed scanner (Umax Powerlook II, Umax Technologies, Inc., Taiwan). Digital images were altered with PHOTOSHOP 6.0 software (Adobe Corporation, San Jose, CA, USA). Carious lesions, periapical pathoses, fake root canals and artificial fillings were created, and inadequate treatment was corrected by application of various image manipulation functions of the software.

KEY LEARNING POINTS

Digital endodontic images can be altered with image processing software. The use of digital radiographic data inevitably raises concerns about security, reliability and the potential for fraud.

Comparison of direct digital and conventional intraoral radiographs in detecting alveolar bone loss

BACKGROUND

Intraoral radiographs are important diagnostic aids in periodontics. The authors conducted a study to compare estimates of bone levels from direct digital and conventional radiographic under normal clinical use.

METHODS

A full-mouth series of conventional radiographs was taken for each of 25 subjects who had periodontitis. A long cone paralleling technique was used for periapical, or PA, images, and a paper sleeve with biting tab was employed for bitewing, or BW, images. A set of direct digital radiographs matching the conventional radiographs was taken for each subject under the same conditions. The distance from the cementoenamel junction to the interproximal alveolar crest on all readable surfaces was measured.

RESULTS

Examiners measured 857 PA image sites and 315 BW image sites matched on both radiographic systems. Paired t test showed significant differences in bone levels between the two systems. Measurements from conventional PA images were higher in all maxillary sextants (P < or = .02), and measurements from digital PA images were higher in mandibular anterior sextants (P = .007). Measurements in digital BW images were higher in mandibular posterior sextants (P = .002). A chi2 analysis of categorical bone levels (normal, early-to-moderate loss or advanced loss) showed significant differences between the imaging systems in revealing bone levels in both PA (P < .04) and BW (P < .001) images. Digital radiographs showed a higher number of sites with bone loss than did conventional radiographs.

CONCLUSIONS

Under normal clinical use, alveolar bone levels revealed on intraoral direct digital radiographs differ from those revealed on conventional radiographs.

CLINICAL IMPLICATIONS

Intraoral direct digital radiographs are not an equivalent substitute for conventional radiographs in evaluating alveolar bone levels.