Impact of cone-beam computed tomography scan mode on the diagnostic yield of chemically simulated external root resorption

DIAGNOSTIC PERFORMANCE OF CONE-BEAM COMPUTED TOMOGRAPHY TO DIAGNOSE IN VIVO/IN VITRO ROOT RESORPTION: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

This review analyses the diagnostic performance of cone-beam computed tomography (CBCT) for the in vivo/in vitro detection of external root resorption (ERR) and critically analyses current and past methods of measuring or classifying ERR in vivo/in vitro in terms of radiation doses and cumulative radiation risks.

METHODS

A diagnostic test accuracy (DTA) protocol was used for a systematic review of diagnostic methods following PRISMA guidelines. The protocol was registered with PROSPERO (ID: CRD42019120513). A thorough and exhaustive electronic search of 6 core electronic databases was performed, applying the ISSG Search Filter Resource. The eligibility criteria were designed [problem-intervention-comparison-outcomes (PICO) statement: Population, Index test, Comparator, Outcome] and methodological quality was assessed by QUADAS-2.

RESULTS

Seventeen papers were selected from a total of 7841 articles. Six in vivo studies were assessed as having a low risk of bias. The overall sensitivity and specificity of CBCT for diagnosis of ERR was 78.12% and 79.25%, respectively. The highest and lowest sensitivity and specificity of CBCT for diagnosis of external root resorption are 42%-98% and 49.3%-96.3%.

DISCUSSION

Most of the selected studies reported quantitative diagnoses with single linear measurements of ERR even though multislice radiographs were available. The cumulative radiation dose (μS) to radiation-sensitive structures, such as the bone marrow, brain and thyroid, was observed to increase using the 3-dimensional (3D) radiography methods reported.

CONCLUSIONS

The highest and lowest sensitivity and specificity of CBCT for diagnosis of external root resorption are 42%-98% and 49.3%-96.3%. The minimum and maximum effective doses of dental CBCT for external root resorption diagnosis are 34 μSv and 1073 μSv.

External root resorption evaluated by CBCT 3D models superimposition

Introduction:

The literature reports the association of external root resorption (ERR) with orthodontic movement. In cases of premolars extractions, orthodontic movement of anterior teeth is usually quite expressive, which are precisely the most susceptible teeth to suffer from ERR.

Objective:

The aim of this study was to assess the root morphology of maxillary canines and incisors in patients submitted to four premolar extraction and orthodontic retraction of the anterior teeth, by means of 3D surface models superimposition and mapping.

Methods:

The sample consisted of six adult patients, five female and one male, with a mean age of 23.5 ± 6.5 years, who underwent orthodontic treatment. All patients presented bimaxillary dental protrusion, with indication of maxillary and mandibular first premolar extractions, followed by the retraction of anterior teeth and space closure. Cone beam CT scans were performed before the beginning of the treatment (T₀) and right after space closure (T₁). 3D models were built at both times and superimposed to identify the root changes for the given period.

Results:

All average differences were close to zero and, even when evaluating the extreme values, the observed changes were always smaller than the accuracy of the CBCT.

Conclusion:

A mild resorption trend was observed, although it was not clinically significant, with values lower than the tomography accuracy.

Multiple idiopathic external cervical root resorption in patient treated continuously with denosumab: a case report

Background

External root resorption is an irreversible loss of dental hard tissue as a result of odontoclastic action. Multiple external cervical root resorptions in permanent teeth are rare. The exact cause of external cervical root resorption is unclear. It is currently well established that RANK/RANKL signaling is essential for osteoclastogenesis and osteoclast-mediated bone resorption. Denosumab is an anti-RANKL antibody used for the treatment of postmenopausal osteoporosis. RANK/RANKL pathway suppression by denosumab is expected to suppress the activity of clastic cells responsible for hard tissue resorption involving both osteoclasts and odontoclasts.

Case presentation

This case report demonstrates aggressive and generalized idiopathic external cervical root resorption that started and advanced during ongoing antiresorptive therapy with the human monoclonal RANKL-blocking antibody denosumab without discontinuation of therapy in a 74-year-old female patient treated for postmenopausal osteoporosis. The extent of resorptive defects was too large and progressively led to fractures of the teeth. The number of teeth involved and the extend of destruction excluded conservative treatment. The affected teeth had to be extracted for functional prosthetic reconstruction.

Conclusions

This finding suggests that treatment with denosumab may be associated with severe and aggressive odontoclastic resorption of multiple dental roots despite an adequate inhibitory effect on osteoclasts in the treatment of osteoporosis. The RANKL-independent pathways of clastic cell formation are likely to be involved in this pathological process.

The impact of digital filters on the diagnosis of simulated root resorptions in digital radiographic systems

OBJECTIVES

To evaluate the influence of digital filters of intraoral radiographic systems on the diagnosis of simulated internal and external root resorptions and image quality.

MATERIALS AND METHODS

Internal root resorption (IRR) and external root resorption (ERR) were simulated in 34 teeth. For image acquisition, two radiographic systems were used: Digora Toto and VistaScan. All filters available in these systems were applied. Three observers scored the detection of root resorptions in a 5-point scale. The noise and the contrast-to-noise ratio (CNR) were calculated. The area under ROC curve, sensitivity, specificity, and accuracy were obtained. One-way ANOVA with Tukey's post hoc tests compared the diagnostic values, noise, and CNR between the filters (α = 0.05).

RESULTS

For ERR, there were no significant differences in diagnostic values between the filters tested for both systems. For IRR, Original and Noise Reduction filters presented higher sensitivity than the Sharpen2 filter for images from Digora Toto, with no differences between the other groups. For VistaScan, there were no significant differences of diagnostic values between the groups studied. Noise values differed among the filters of both systems. The CNR of the filters differed only for the bone region for Digora Toto, while for VistaScan, both tooth and bone regions differed.

CONCLUSIONS

Despite promoting changes in pixel intensities and affecting the noise level of the radiographic images, the digital filters of Digora Toto and VistaScan systems do not affect the diagnosis of internal or external root resorptions.

CLINICAL RELEVANCE

Digital filters are common tools in digital radiographic systems and may be used by the professional without impairment in root resorptions diagnosis.

The effect of two different types of forces on possible root resorption in relation to dentin phosphoprotein levels: a single-blind, split-mouth, randomized controlled trial

Background

The purpose of this 2-arm-parallel split-mouth trial was to evaluate and compare the extent of possible root resorption using dentin phosphoprotein levels in gingival crevicular fluid between controlled continuous and intermittent orthodontic force groups.

Materials and methods

A sample of 16 maxillary first premolars from 8 patients requiring bilateral extractions of the upper first premolars as part of their orthodontic treatment were recruited. A buccally directed continuous force of 150 g, reactivated after 28 days, was applied to the upper first premolar on one side for 8 weeks. On the contralateral first premolar, a buccally directed intermittent force (21 days on, 7 days off) of the same magnitude was applied for the same period. Gingival crevicular fluid samples were collected at the beginning of the study, 1st, 3rd, 4th and 5th week, and at the end of the study to quantify and compare dentin phosphoprotein levels in both groups.

Results

Dentin phosphoprotein levels showed a higher concentration in the continuous force group than the intermittent force group in week 4 and 8 of sample collection; where the differences were statistically significant (95% CI 0.007–0.14; P < .04) and (95% CI 0.02–0.17; P < .04) respectively. No harm was observed.

Conclusions

Dentin phosphoprotein was found to be a useful early biomarker to detect and monitor root resorption, showing that the application of an intermittent orthodontic force caused less root resorption than a continuous force.

Trial registration

NCT04825665 ClinicalTrials.gov. Registered 1 April 2021—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04825665.

Scatter-to-primary ratio in dentomaxillofacial cone-beam CT: effect of field of view and beam energy

OBJECTIVE

The aim of this study was to evaluate the effect of field of view (FOV) and beam energy on the scatter-to-primary ratio (SPR) in dental cone-beam CT (CBCT).

METHODS

An anthropomorphic phantom representing an adult male (ATOM Max 711-HN, Norfolk, VA, USA) was scanned using the 3D Accuitomo 170 CBCT (J. Morita, Kyoto, Japan) using 11 FOVs. During each scan, half of the X-ray beam was blocked. Each scan was performed at three exposure settings with varying beam energy and equal radiation dose: 90 kV 5 mA, 77 kV 7.5 mA and 69 kV 10 mA. The SPR was estimated by measuring the grey values in the blocked and non-blocked regions of the RAW data. The effect of FOV on SPR was evaluated using Dunn's multiple comparison test, and the effect of the exposure settings was compared using a Wilcoxon signed rank test.

RESULTS

Larger FOVs showed increased scatter. FOVs with a shorter isocenter-detector distance showed a particularly high SPR. Most intercomparisons between FOVs were statistically significant. The largest difference was found between 17 × 12 cm and 6 × 6 cm (lower jaw), with the former showing a 4.9-fold higher SPR. The effect of beam energy was relatively small and varied between FOV sizes and positions.

CONCLUSION

While the choice of FOV size and position is determined by the diagnostic region of interest, the image quality deterioration for large FOVs due to scatter provides another incentive to limit the FOV size as much as possible.

Influence of the image file format of digital periapical radiographs on the diagnosis of external and internal root resorptions

OBJECTIVES

To evaluate the influence of different image file formats of digital radiographic images on the diagnosis of external (ERR) and internal root resorption (IRR).

MATERIALS AND METHODS

Thirty-four human teeth were selected. For ERR, 20 teeth were used (10 control and 10 with simulated ERR), and for IRR, 14 teeth were used (before and after IRR simulation). Digital periapical radiographs were acquired using the Digora Toto system and exported in four different image file formats: TIFF, BMP, PNG, and JPEG, totaling 192 radiographs. Five examiners evaluated the images using the JPEGView software and scored the detection of ERR or IRR on a 5-point scale. Sensitivity, specificity, accuracy, and the area under the ROC curve were obtained for the diagnosis of ERR and IRR in the different image file formats. Two-way ANOVA compared the diagnostic values between the file formats and the Kappa test assessed intra- and inter-examiner agreement. The significance level was set at 5% (α = 0.05).

RESULTS

The mean values of intra-examiner agreement were substantial (0.740) for ERR and almost perfect (0.836) for IRR and, inter-examiner was fair (0.263) and moderate (0.421), respectively. No statistically significant differences were found among the different file formats for the diagnostic values of ERR and IRR.

CONCLUSION

The file format of digital radiographs does not influence the diagnosis of ERR and IRR.

CLINICAL RELEVANCE

Digital radiographic images may be susceptible to computational factors; however, they can be stored in multiple file formats without affecting the diagnosis of dental root resorptions.

Diagnostic efficacy of different cone beam computed tomography scanning protocols in the detection of chemically simulated external root resorption

OBJECTIVES

The aim of this study was to evaluate the efficacy of different high-resolution cone beam computed tomography protocols in the diagnosis of chemically simulated external root resorption (ERR).

STUDY DESIGN

ERR was simulated in 3 sizes by using an acid decalcification protocol in the cervical, middle, and apical thirds of 30 single-rooted premolars. Four scans of each tooth were acquired with different voxel sizes: 0.080, 0.085, 0.120, and 0.133 mm. The images were analyzed by 2 blinded evaluators for the presence of ERR. The evaluation of diagnostic performance was based on receiver operating characteristic (ROC) curve analysis.

RESULTS

No statistically significant differences were found in the detection of ERR with regard to lesion sizes or the different root thirds. Areas under the ROC curve were 0.901, 0.892, 0.887, and 0.767 for voxel sizes of 0.080, 0.085, 0.120, and 0.133 mm, respectively. Voxel sizes of 0.080 and 0.085 mm presented significantly larger areas under the ROC curve compared with the voxel size of 0.133 mm. There were no statistically significant differences among the protocols with the use of voxel sizes of 0.080, 0.085, and 0.120 mm.

CONCLUSIONS

Cone beam computed tomography examinations with higher-resolution protocols demonstrated better performance in the diagnosis of ERR. Further investigations using simulations that more closely resemble the actual ERR process are warranted.

Accuracy of Different Imaging CBCT Systems for the Detection of Natural External Radicular Resorption Cavities: An Ex Vivo Study

OBJECTIVE

The aim of this study was to compare the sensitivity and specificity of 3 different systems of cone-beam computed tomography (CBCT) in the detection of natural external root resorption (ERR) cavities using microtomography as the gold standard.

METHOD

A sample of 126 ex vivo teeth were submitted to a microtomography examination to verify the presence/absence of ERR cavities. Then, they were divided into the control group: 85 teeth that did not present with an ERR cavity; and experimental group: 41 teeth that presented with 1 or more ERR cavities. The size of the natural ERR cavities varied from 2.46 mm³ to 3.11 mm³, which corresponded to cavities of 1.67 mm and 1.81 mm in diameter, respectively. The teeth were placed on a dry human mandible for scanning in each of the 3 protocols with different voxel sizes: 0.25 mm, 0.20 mm, and 0.166 mm.

RESULTS

The accuracy of the 3 protocols evaluated in this study are listed in decreasing order: 60.3% for a voxel size of 0.20 mm, 56.7% for a voxel size of 0.166 mm, and 46.7% for a voxel size of 0.25 mm; these are smaller values than previous studies have obtained using artificial ERR cavities. Statistically significant results were not found among the 3 CBCT protocols that were used (P > .05), and the receiver operating characteristic curve shows the small differences found between the protocols.

CONCLUSION

The results indicate that CBCT presents, for natural ERR, lower sensitivity and specificity values than those detected in previous studies of artificial cavities. The results demonstrate that natural ERR is neither easily observed nor accurately located by CBCT, as previous studies using artificial ERR indicated.

Diagnosis of external root resorption in teeth close and distant to zirconium implants: influence of acquisition parameters and artefacts produced during cone beam computed tomography

AIM

To assess the influence of artefacts, the metal artefact reduction (MAR) tool and kilovoltage (kVp) on the diagnosis of simulated external root resorption (ERR) in teeth close and distant to zirconium implants in cone beam computed tomography (CBCT) images.

METHODOLOGY

Cavities (0.62 mm in diameter and 0.19 mm deep) were created in the apical thirds of 12 roots on the buccal, lingual, distal or mesial surface; ten roots served as controls. The roots were randomly positioned in the first and second right and left premolar sockets of a dry human mandible, and a zirconium implant was placed in the socket of the first right molar. A ProMax 3D unit varying kVp (70, 80, or 90 kVp) and with the MAR tool activated or not was used to obtain CBCT scans. Five examiners evaluated all images to determine the area under the receiver operating characteristic (ROC) curve, sensitivity and specificity.

RESULTS

The ROC values and sensitivity were not affected by MAR or artefacts regardless of the distance to the implant (P > 0.05), whilst increasing kVp from 70 to 90 led to a significant increase in these values (P = 0.0202 and 0.0199, respectively). Specificity was not affected by the factors studied (P > 0.05).

CONCLUSIONS

Amongst the factors studied, only kVp influenced the diagnosis of simulated external root resorption in CBCT images. Increasing kVp from 70 to 90 improved the accuracy in diagnosing the simulated lesions.

Accuracy of linear and volumetric measurements of artificial ERR cavities by using CBCT images obtained at 4 different voxel sizes and measured by using 4 different software: an ex vivo research

OBJECTIVES

To compare the accuracy of linear and volumetric measurements of artificial external root resorption (ERR) cavities by cone beam CT (CBCT) images obtained at four voxel sizes and by using four different software ex vivo.

METHODS

ERR cavities were created on 40 extracted single rooted anterior teeth. Images were obtained by using Planmeca CBCT unit at endo mode (0.075 mm); high-resolution mode (0.1 mm); high-definition mode (0.15 mm) and normal resolution mode (0.2 mm) voxel sizes. Images were analyzed by two observers using four different software (Romexis, 3D Doctor, ITK-SNAP, and OsiriX). (1) Diameter; (2) height; (3) depth; and (4) volume of the ERR were measured. CBCT measurements were then compared with direct physical measurements. ANOVA was used with general linear model analysis. The significance level was set at p < 0.05.

RESULTS

One-way ANOVA general linear model analysis showed no significant difference between or within observers for diameter, height, depth and volume measurements (p > 0.05). We found significant differences for diameter and volume measurements among softwares in terms of mean differences as compared to mean standard direct measurements (p < 0.05). We found statistically significant differences among voxel sizes and software for height measurements (p < 0.05). In addition, we found significant differences for diameter and volume measurements (p < 0.05) suggesting more accurate measurements for the cervical region when compared to apical region.

CONCLUSIONS

Observers using CBCT images obtained at four voxel sizes performed similarly in the quantification of artificial ERR with clinically insignificant distinction between CBCT softwares used.

Comparison between Two Radiological Methods for Assessment of Tooth Root Resorption: An In Vitro Study

Purpose

This study aims to verify the validity of the radiographic image and the most effective radiological techniques for the diagnosis of root resorption to prevent, cure, and reduce it and to verify if radiological images can be helpful in medical and legal situations.

Methods

19 dental elements without root resorption extracted from several patients were examined: endooral and panoramic radiographs were performed, with traditional and digital methods. Then the root of each tooth was dipped into 3-4 mm of 10% nitric acid for 24 hours to simulate the resorption of the root and later submitted again to radiological examinations and measurements using the same criteria and methods.

Results

For teeth with root resorption the real measurements and the values obtained with endooral techniques and digital sensors are almost the same, while image values obtained by panoramic radiographs are more distorted than the real ones.

Conclusions

Panoramic radiographs are not useful for the diagnosis of root resorption. The endooral examination is, in medical and legal fields, the most valid and objective instrument to detect root resorption. Although the literature suggests that CBCT is a reliable tool in detecting root resorption defects, the increased radiation dosage and expense and the limited availability of CBCT in most clinical settings accentuate the outcome of this study.