A novel method to estimate the volume of bone defects using cone-beam computed tomography: an in vitro study

Effects of polymethyl methacrylate-based bone cement graft for treating excessive gingival display and its dimensional facial changes: 12-Month clinical study

Objective

to present a 12-month follow-up with photographic and tomographic analyses of the effect of polymethyl methacrylate-based bone cement graft (PMMA) in gingival exposure (GE) in patients with excessive gingival display (EGD).

Methods

Twelve patients with EGD were included. The PMMA was surgically placed. A frontal and lateral photograph protocol was performed at baseline (T0), 3 (T3), 6 (T6), and 12 months (T12) post-operatively. Soft tissue cone-beam computed tomography (ST-CBCT) was performed at T0 and T12. Measures included GE, length of the lip vermilion (LLV), lip shape (LS), nose width (NW), filter width (FW), nasolabial angle (NAS) while smiling, and nasolabial angle at rest (NAR). The height, thickness, and volume of the cement graft were also measured in the ST-CBCT. The comparisons were performed by Kruskal-Wallis test at 5 % of significance (p < 0.05).

Results

The height, thickness, and volume of the PMMA were respectively 12.84 ± 1.59 mm, 3.83 ± 0.53, and 1532.02 ± 532.52 mm3. PMMA significantly decreased GE from 8.33 ± 1.25 mm (T0) to 6.60 ± 0.93 mm (T12) (p < 0.01). NAR was 98.34 ± 9.28° at T0 and increased to 105.13 ± 7.33° at T12; however, the angle value was not statistically different (p = 0.08). LLV, LS, NW, FW, and NAS did not exhibit statistical differences between the baseline and follow-up periods.

Conclusions

PMMA significantly decreased GE in a 12-month follow-up without influencing adjacent soft tissue anatomical structures.

Accuracy of formula-based volume and image segmentation-based volume in calculation of preoperative cystic jaw lesions' volume

OBJECTIVE

The aim of this study was to assess the accuracy of formula-based volume measurements and the 3D volume analysis with different software packages in the calculation of preoperative cystic jaw lesions' volume. The secondary aim was to assess the reliability and the accuracy of 3 imaging software programs for measuring the cystic jaw lesions' volume in CBCT images.

MATERIALS AND METHODS

This study consisted of two parts: an in vitro part using 2 dry human mandibles that were used to create simulated osteolytic lesions to assess the accuracy of the volumetric analysis and formula-based volume. As a gold standard, the volume of each bone defect was determined by taking an impression using rapid soft silicone (Vinylight) and then quantifying the volume of the replica. Afterward, each tooth socket was scanned using a high-resolution CBCT. A retrospective part using archived CBCT radiographs that were taken from the database of the outpatient clinic of the oral and maxillofacial radiology department, Faculty of Dentistry, Minia University to assess the reliability of the 3 software packages. The volumetric data set was exported for volume quantification using the 3 software packages (MIMICS-OnDemand and InVesalius software). Also, the three greatest orthogonal diameters of the lesions were calculated, and the volume was assessed using the ellipsoid formula. Dunn's test was used for pair-wise comparisons when Friedman's test was significant. The inter-examiner agreement was assessed using Cronbach's alpha reliability coefficient and intra-class correlation coefficient.

RESULTS

Regarding the results of the retrospective part, there was a statistically significant difference between volumetric measurements by equation and different software (P value < 0.001, Effect size = 0.513). The inter-observer reliability of the measurements of the cystic lesions using the different software packages was very good. The highest inter-examiner agreement for volume measurement was found with InVesalius (Cronbach's alpha = 0.992). On the other hand, there was a statistically significant difference between dry mandible volumetric measurements and Gold Standard. All software showed statistically significantly lower dry mandible volumetric measurements than the gold standard.

CONCLUSION

Computer-aided assessment of cystic lesion volume using InVesalius, OnDemand, and MIMICS is a readily available, easy to use, non-invasive option. It confers an advantage over formula-based volume as it gives the exact morphology of the lesion so that potential problems can be detected before surgery. Volume analysis with InVesalius software was accurate in determining the volume of simulated periapical defects in a human cadaver mandible as compared to true volume. InVesalius software proved that open-source software can be robust yet user-friendly with the advantage of minimal cost to use.

Volumetric Assessment of Apical Periodontitis Using Cone-Beam Computed Tomography-A Systematic Review

This systematic review aimed to investigate the scientific literature on volumetric studies concerning the diagnosis and treatment of apical periodontitis using CBCT. A systematic review protocol was written following the preferred reporting items for the systematic reviews and meta-analyses (PRISMA) checklist. Four electronic databases were searched for relevant publications in English, which were published up to 21 January 2023. The inclusion criteria and corresponding search keys were applied. The risk of bias was assessed using the Joanna Briggs Institute Meta-Analysis of Statistic Assessment and Review Instrument. The search strategy identified 202 studies, with 123 studies excluded during the title and abstract screening and 47 studies left for full text screening. A total of 17 studies met the inclusion criteria. The lesion volume was measured and classified according to different indices which compared the effectiveness of their diagnostics. Moreover, the volume of AP lesions increased with the thickness of the maxillary sinus mucosa in primary and secondary infections and decreased due to endodontic treatment. Volumetric measurements using CBCT are useful in the correct definition of periapical tissue pathosis using a CBCT periapical volume index and assessment of the dynamics of the treatment of apical lesions.

Sphericity of periapical lesion and its relation to the novel CBCT periapical volume index

BACKGROUND

The purpose of this study was to assess the sphericity of periapical lesions and its relation to the cone beam computed tomography periapical volume index (CBCTPAVI).

METHODS

261 periapical lesions were assessed using cone beam computed tomography images from InteleViewer^TM. Three-dimensional analysis of the lesions was conducted using analytical imaging software Mimics Research^TM. Lesion volume and surface area measurements were determined using the semi-automatic segmentation technique and these measurements were then used to determine lesion sphericity and CBCTPAVI score. One-way analysis of variance with post-hoc Tuckey test was used to assess for differences in sphericity among CBCTPAVI groups.

RESULTS

The mean sphericity of periapical lesions was 62%. Periapical lesions with larger CBCTPAVI scores were significantly less spherical than lesions with smaller CBCTPAVI scores.

CONCLUSIONS

Periapical lesions of endodontic origin are mostly semi-spherical in their spread and as CBCTPAVI score increases, sphericity decreases, indicating that larger lesions expand less uniformly compared with smaller lesions. Clinicians should be aware that lesions of increased volume, have less sphericity, and are thus elongated or stretched in one or more anatomical plane. This information will assist clinicians in planning and performing periapical surgery and may aid in differential diagnosis of radiolucent jaw lesions.

Present status and future directions: Imaging techniques for the detection of periapical lesions

Diagnosing and treating apical periodontitis (AP) in an attempt to preserve the natural dentition, and to prevent the direct and indirect systemic effects of this condition, is the major goal in endodontics. Considering that AP is frequently asymptomatic, and is most often associated with a lesion in the periapex of the affected tooth, within the maxillary bones, imaging becomes of paramount importance for the diagnosis of the disease. The aim of this narrative review was to investigate the most relevant classic and current literature to describe which are, to date, the diagnostic imaging systems most reliable and advanced to achieve the early and predictable detection of AP, the best measures of the lesions and the disclosure of the different features of the disease. Dental panoramic tomography (DPT) is a classic exam, considered still useful to provide the basic diagnosis of AP in certain districts of the maxillary bones. Periapical radiographs (PRs) represent a valid routine examination, with few, known limitations. Cone-beam computed tomography (CBCT) is the only system that ensures the early and predictable detection of all periapical lesions in the jaws, with the minor risk of false positives. These techniques can be successfully implemented, with ultrasounds (USI) or magnetic resonance (MRI) imaging, exams that do not use ionising radiations. MRI and USI provide information on specific features of the lesions, like the presence and amount of vascular supply, their content and their relationship with the surrounding soft tissues, leading to differential diagnoses. Further, all the three-dimensional systems (CBCT, USI and MRI) allow the volumetric assessment of AP. Pioneering research on artificial intelligence is slowly progressing in the detection of periapical radiolucencies on DPTs, PRs and CBCTs, however, with promising results. Finally, it is established that all imaging techniques have to be associated with a thorough clinical examination and a good degree of calibration of the operator.

How well do integrated 3D models predict alveolar defects after treatment with clear aligners?

OBJECTIVES

To evaluate the accuracy of integrated models (IMs) constructed by pretreatment cone-beam computed tomography (pre-CBCT) in diagnosing alveolar defects after treatment with clear aligners.

MATERIALS AND METHODS

Pre-CBCT and posttreatment cone-beam computed tomography (CBCT) scans from 69 patients who completed nonextraction treatment with clear aligners were collected. The IMs comprised anterior teeth in predicted positions and alveolar bone from pre-CBCT scans. The accuracy of the IMs for identifying dehiscences or fenestrations was evaluated by comparing the means of the defect volumes, absolute mean differences, and Pearson correlation coefficients with those measured from post-CBCT scans. Defect prediction accuracy was assessed by sensitivity, specificity, positive predictive values, and negative predictive values. Factors possibly affecting changes in mandibular alveolar defects were analyzed using a mixed linear model.

RESULTS

The IM measurements showed mean deviations of 2.82 ± 9.99 mm3 for fenestrations and 3.67 ± 9.93 mm3 for dehiscences. The absolute mean differences were 4.50 ± 9.35 mm3 for fenestrations and 5.17 ± 9.24 mm3 for dehiscences. The specificities of the IMs were higher than 0.8, whereas the sensitivities were both lower (fenestration = 0.41; dehiscence = 0.53). The positive predictive values were unacceptable (fenestration = 0.52; dehiscence = 0.62), and the overall reliability was low (<0.80). Molar distalization and proclination were positively correlated with significant increases in alveolar defects at the mandibular incisors after treatment.

CONCLUSIONS

Alveolar defects after clear aligner treatment cannot be simulated accurately by IMs constructed from pre-CBCT. Caution should be taken in the treatment of crowding with proclination and molar distalization for the safety of alveolar bone at the mandibular incisors.

Low-dose Multidetector Computed Tomographic and Cone-beam Computed Tomographic Protocols for Volumetric Measurement of Simulated Periapical Lesions

INTRODUCTION

The purpose of this study was to evaluate the accuracy of low-dose multidetector computed tomographic (LD-MDCT) imaging for the volumetric measurement of simulated periapical lesions.

METHODS

Eighteen monoradicular teeth were introduced in bone blocks, and periapical lesions were simulated at the periapical region of each tooth. All teeth were imaged using 4 acquisition protocols: large (dentoalveolar) field of view (FOV) cone-beam computed tomographic (CBCT) imaging (120 kV, 5 mA, and 0.2-mm voxel), small (dental) FOV CBCT imaging (90 kV, 10 mA, and 0.2-mm voxel), standard multidetector computed tomographic imaging (120 kV, 50 mA, and 0.62-mm voxel), and LD-MDCT imaging (120 kV, 10 mA, and 0.62-mm voxel). Tomographic images were evaluated by a single trained and calibrated examiner (intraclass correlation coefficient = 0.991) using ITK-SNAP segmentation software (University of Pennsylvania, Philadelphia, PA). The gold standard was obtained by the impressions of the lesions with regular fluid addition silicone and individual weighing using a precision analytical scale. Data were evaluated by the repeated measures analysis of variance test; the significance level was defined as P < .05.

RESULTS

No statistical differences (P > .05) were found among the groups regardless of the device, milliamperage, FOV, or voxel size.

CONCLUSIONS

LD-MDCT shows performance comparable with other standard reference methods for measuring the volume of periapical lesions and can be a useful and safe protocol in clinical situations in which CBCT imaging is not available, such as in cases of patients admitted to hospitals.

A Clinical Evaluation of Cone-beam Computed Tomography: Implications for Endodontic Microsurgery

INTRODUCTION

Cone-beam computed tomographic (CBCT) imaging is a valuable diagnostic tool for endodontics. Some studies report that CBCT images have limitations in representing the true clinical presentation. This prospective, in vivo study compared limited field of view (LFOV) CBCT measurements with clinical measurements made during endodontic surgery.

METHODS

Eighty-seven subjects requiring endodontic surgery and LFOV CBCT acquisition of the surgical site were enrolled. Data collection involved clinicians answering standardized questions during the radiographic and surgical assessment. Intraoperatively, data were collected and photographically documented. Postoperatively, CBCT scans were evaluated by 3 calibrated, board-certified specialists: 2 endodontists and 1 oral and maxillofacial radiologist. The 2 subsets of data were compared through statistical analysis to quantify their relationship.

RESULTS

The subjects included 65 maxillary and 29 mandibular teeth from 87 subjects: 25 women and 62 men with an average age of 42 years old. The CBCT evaluators correctly identified the presence or absence of buccal plate fenestrations with 91.0% accuracy (95% confidence interval, 83.1-96.0) with 89.4% sensitivity and 92.9% specificity. The area of fenestrations measured clinically (mean = 19.6 ± 33.4 mm²) was generally larger than the area measured by CBCT imaging (mean across CBCT evaluators = 12.2 ± 19.1 mm²). Fenestration size in the maxillary arch was more likely to be underestimated than in the mandibular arch (P < .0001). Vertical bone height was also underestimated when measured on CBCT imaging.

CONCLUSIONS

Based on the findings of this study, LFOV CBCT imaging accurately identifies the presence or absence of buccal plate fenestrations, yet, when a fenestration is present, underestimates its area.

Three-dimensional qualitative and quantitative analyses of the effect of periradicular lesions on the outcome of regenerative endodontic procedures: A prospective clinical study

OBJECTIVES

Qualitative and quantitative evaluation of the outcomes of regenerative endodontic procedure (REP) on human immature necrotic teeth with apical periodontitis using cone-beam computed tomography (CBCT) MATERIALS AND METHODS: Immature permanent teeth (n = 50) with necrotic pulp and periradicular pathosis were treated with a cell-homing concept-based REP. Following the procedure, a limited field-of-view CBCT scan was obtained. At each recall session (6, 12, 18 months), clinical tests were performed, and a digital periapical radiograph was taken. When significant radiographic changes were evident in the follow-up, a final CBCT scan was taken for qualitative and quantitative assessment. These initial and follow-up CBCT scans were assessed for quantification of changes in root length, pulp space diameter and periradicular lesion size. The data were statistically analysed using t test, one-way ANOVA, post hoc test and paired t test (P = 0.05).

RESULTS

Of the teeth, 94.6% were clinically successful based on the lack or regression of signs and symptoms after 48 months follow-up. REP resulted in a statistically significant increase in root length, decrease in pulp space diameter and periradicular radiolucency (P < 0.05). CBCT images illustrated various patterns of root maturation including an increased thickening of the canal walls and continued root maturation (37.1%), continued root development with the apical foramen remaining open (57.1%), severe calcification (obliteration) of the canal space (2.9%) and hard tissue barrier formation in the canal space between the coronal plug and the root apex (2.9%).

CONCLUSION

This study highlighted that the expected outcome of radiographic root development was less predictable when immature permanent teeth with periradicular pathosis were treated with REP.

CLINICAL RELEVANCE

The size and extent (expansion/destruction of the cortical plate) of periradicular lesions and abscesses influence the outcome of REP. These factors must be taken into consideration during treatment planning.

Binary Decision Trees for Preoperative Periapical Cyst Screening Using Cone-beam Computed Tomography

INTRODUCTION

Cone-beam computed tomographic (CBCT) analysis allows for 3-dimensional assessment of periradicular lesions and may facilitate preoperative periapical cyst screening. The purpose of this study was to develop and assess the predictive validity of a cyst screening method based on CBCT volumetric analysis alone or combined with designated radiologic criteria.

METHODS

Three independent examiners evaluated 118 presurgical CBCT scans from cases that underwent apicoectomies and had an accompanying gold standard histopathological diagnosis of either a cyst or granuloma. Lesion volume, density, and specific radiologic characteristics were assessed using specialized software. Logistic regression models with histopathological diagnosis as the dependent variable were constructed for cyst prediction, and receiver operating characteristic curves were used to assess the predictive validity of the models. A conditional inference binary decision tree based on a recursive partitioning algorithm was constructed to facilitate preoperative screening.

RESULTS

Interobserver agreement was excellent for volume and density, but it varied from poor to good for the radiologic criteria. Volume and root displacement were strong predictors for cyst screening in all analyses. The binary decision tree classifier determined that if the volume of the lesion was >247 mm³, there was 80% probability of a cyst. If volume was <247 mm³ and root displacement was present, cyst probability was 60% (78% accuracy).

CONCLUSIONS

The good accuracy and high specificity of the decision tree classifier renders it a useful preoperative cyst screening tool that can aid in clinical decision making but not a substitute for definitive histopathological diagnosis after biopsy. Confirmatory studies are required to validate the present findings.

Post-processing open-source software for the CBCT monitoring of periapical lesions healing following endodontic treatment: technical report of two cases

OBJECTIVES

To describe the use of open-source software for the post-processing of CBCT imaging for the assessment of periapical lesions development after endodontic treatment.

METHODS

CBCT scans were retrieved from endodontic records of two patients. Three-dimensional virtual models, voxel counting, volumetric measurement (mm³) and mean intensity of the periapical lesion were performed with ITK-SNAP v. 3.0 software. Three-dimensional models of the lesions were aligned and overlapped through the MeshLab software, which performed an automatic recording of the anatomical structures, based on the best fit. Qualitative and quantitative analyses of the changes in lesions size after treatment were performed with the 3DMeshMetric software.

RESULTS

The ITK-SNAP v. 3.0 showed the smaller value corresponding to the voxel count and the volume of the lesion segmented in yellow, indicating reduction in volume of the lesion after the treatment. A higher value of the mean intensity of the segmented image in yellow was also observed, which suggested new bone formation. Colour mapping and "point value" tool allowed the visualization of the reduction of periapical lesions in several regions.

CONCLUSIONS

Researchers and clinicians in the monitoring of endodontic periapical lesions have the opportunity to use open-source software.

Cone-Beam Computed Tomography contrast validation of an artificial periodontal phantom for use in endodontics

Validation of image processing techniques such as endodontic segmentations in cone-beam computed tomography (CBCT) is a challenging issue because of the lack of ground truth in in vivo experiments. The purpose of our study was to design an artificial surrounding tissues phantom able to provide CBCT image quality of real extracted teeth, similar to in vivo conditions. Note that these extracted teeth could be previously scanned using micro computed tomography (μCT) to access true quantitative measurements of the root canal anatomy. Different design settings are assessed in our study by comparison to in vivo images, in terms of the contrast-to-noise ratio (CNR) obtained between different anatomical structures. Concerning the root canal and the dentine, the best design setup allowed our phantom to provide a CNR difference of only 3% compared to clinical cases.

Reliability and Reproducibility of Manual and Automated Volumetric Measurements of Periapical Lesions

INTRODUCTION

The present study aimed to test the reliability and reproducibility of 2 methods: manual and automated segmentation (using a threshold-based region growing algorithm) for measuring the volume of periapical lesions.

METHODS

A total of 43 cone-beam computed tomographic scans (14 men and 29 women, mean age of 54.6 ± 8.5 years) were analyzed by 3 observers. Intraobserver reproducibility and interobserver reliability were assessed using the intraclass correlation coefficient. Parametric correlation between manual and automated volumetric measurements was performed. In addition, the Student t test was also used to compare the mean time required for manual and automated volumetric measurements.

RESULTS

Automated segmentation showed slightly higher intraclass correlation coefficient values for all observers. A strong significant correlation was found between manual and automated volumetric measurements performed by the 3 observers. A significant difference in the mean procedure time was also found between both methods (P = .001).

CONCLUSIONS

Within the limitations of this study, the present results suggest that automated segmentation with a region growing algorithm is faster and slightly more reliable to calculate the volume of periapical lesions.

Influence of CBCT parameters on the output of an automatic edge-detection-based endodontic segmentation

OBJECTIVES

To determine the optimal CBCT settings for an automatic edge-detection-based endodontic segmentation procedure by assessing the accuracy of the root canal measurements.

METHODS

12 intact teeth with closed apexes were cut perpendicular to the root axis, at pre-determined levels to the reference plane (the first section made before acquisition). Acquisitions of each specimen were performed with Kodak 9000(®) 3D (76 µm, 14 bits; Kodak Carestream Health, Trophy, France) by using different combinations of milliamperes and kilovolts. Three-dimensional images were displayed and root canals were segmented with the MeVisLab software (edge-detection-based method; MeVis Research, Bremen, Germany). Histological root canal sections were then digitized with a 0.5- to 1.0-µm resolution and compared with equivalent two-dimensional cone-beam reconstructions for each pair of settings using the Pearson correlation coefficient, regression analysis and Bland-Altman method for the canal area and Feret's diameter. After a ranking process, a Wilcoxon paired test was carried out to compare the pair of settings.

RESULTS

The best pair of acquisition settings was 3.2 mA/60 kV. Significant differences were found between 3.2 mA/60 kV and other settings (p < 0.05) for the root canal area and for Feret's diameter.

CONCLUSIONS

The quantitative analyses of the root canal system with the edge-detection-based method could depend on acquisition parameters. Improvements in segmentation still need to be carried out to ensure the quality of the reconstructions when we have to deal with closer outlines and because of the low spatial resolution.

3D dento-maxillary osteolytic lesion and active contour segmentation pilot study in CBCT: semi-automatic vs manual methods

OBJECTIVES

This study was designed to evaluate the reliability of a semi-automatic segmentation tool for dento-maxillary osteolytic image analysis compared with manually defined segmentation in CBCT scans.

METHODS

Five CBCT scans were selected from patients for whom periapical radiolucency images were available. All images were obtained using a ProMax® 3D Mid Planmeca (Planmeca Oy, Helsinki, Finland) and were acquired with 200-μm voxel size. Two clinicians performed the manual segmentations. Four operators applied three different semi-automatic procedures. The volumes of the lesions were measured. An analysis of dispersion was made for each procedure and each case. An ANOVA was used to evaluate the operator effect. Non-paired t-tests were used to compare semi-automatic procedures with the manual procedure. Statistical significance was set at α = 0.01.

RESULTS

The coefficients of variation for the manual procedure were 2.5-3.5% on average. There was no statistical difference between the two operators. The results of manual procedures can be used as a reference. For the semi-automatic procedures, the dispersion around the mean can be elevated depending on the operator and case. ANOVA revealed significant differences between the operators for the three techniques according to cases.

CONCLUSIONS

Region-based segmentation was only comparable with the manual procedure for delineating a circumscribed osteolytic dento-maxillary lesion. The semi-automatic segmentations tested are interesting but are limited to complex surface structures. A methodology that combines the strengths of both methods could be of interest and should be tested. The improvement in the image analysis that is possible through the segmentation procedure and CBCT image quality could be of value.

Periapical repair following endodontic surgery: two- and three-dimensional imaging evaluation methods

This study quantitatively assessed the periapical bone repair following endodontic surgery, using planimetric evaluation based on two- (conventional and digital intraoral radiographic images - IRs) and three-dimensional (cone beam computed tomography - CBCT) evaluation. Eleven maxillary anterior teeth (of 11 patients) with periapical bone lesions and indication for surgical endodontic treatment were selected. IRs and CBCT images were acquired before the endodontic surgery, and 48 h, 4, and 8-months after the surgery. In each period of evaluation, the area (mm2) of the bone lesion was measured in the images, and the values for the three methods were compared. The area in the CBCT images was measured in the mesio-distal sections comprising the largest diameter of the lesion. Data were submitted to repeated measures 2-way ANOVA and t-tests with Bonferroni correction. There was significant difference between the periods of evaluation (p=0.002) regarding the assessed periapical bone lesion area. There was no statistically significant difference between the methods of evaluation (p=0.023). In the CBCT images the lesion areas were 10% larger than those observed in the conventional IRs (22.84 mm2) and 15% larger than those observed in the digital IRs (21.48 mm2). From the baseline (40.12 mm2) to 4 (20.06 mm2) and 8-months (9.40 mm2), reductions of 50 and 77% in the lesion area, respectively, were observed (p<0.0001). From 4 to 8-months, this value was 53%. Progressive bone repair could be seen from 48 h to 8-months following endodontic surgery based on two- (conventional and digital IRs) and three-dimensional (CBCT) evaluation. CBCT images provided results similar to those assessed by means of IRs.

Radiographic volume analysis as a novel tool to determine nasopalatine duct cyst dimensions and its association with presenting symptoms and postoperative complications

OBJECTIVES

The aims of the study were to use cone beam computed tomography (CBCT) images of nasopalatine duct cysts (NPDC) and to calculate the diameter, surface area, and 3D-volume using a custom-made software program. Furthermore, any associations of dimensions of NPDC with age, gender, presence/absence of maxillary incisors/canines (MI/MC), endodontic treatment of MI/MC, presenting symptoms, and postoperative complications were evaluated.

MATERIAL AND METHODS

The study comprised 40 patients with a histopathologically confirmed NPDC. On preoperative CBCT scans, curves delineating the cystic borders were drawn in all planes and the widest diameter (in millimeter), surface area (in square millimeter), and volume (in cubic millimeter) were calculated.

RESULTS

The overall mean cyst diameter was 15 mm (range 7-47 mm), the mean cyst surface area 566 mm(2) (84-4,516 mm(2)), and the mean cyst volume 1,735 mm(3) (65-25,350 mm(3)). For 22 randomly allocated cases, a second measurement resulted in a mean absolute aberration of ±4.2 % for the volume, ±2.8 % for the surface, and ±4.9 % for the diameter. A statistically significant association was found for the CBCT determined cyst measurements and the need for preoperative endodontic treatment to MI/MC and for postoperative complications.

CONCLUSION

In the hands of a single experienced operator, the novel software exhibited high repeatability for measurements of cyst dimensions. Further studies are needed to assess the application of this tool for dimensional analysis of different jaw cysts and lesions including treatment planning.

CLINICAL RELEVANCE

Accurate radiographic information of the bone volume lost (osteolysis) due to expansion of a cystic lesion in three dimensions could help in personalized treatment planning.

CBCT-based volume of simulated root resorption - influence of FOV and voxel size

AIM

To examine the influence of the field of view (FOV) and voxel size on the measurement of the volume of simulated internal root resorption (IRR) lesions through cone-beam computed tomography (CBCT).

METHODOLOGY

Eleven single-rooted teeth with IRR simulated by acid demineralization were studied. CBCT images were acquired using large FOV (voxel sizes of 0.200, 0.250 and 0.300 mm) and limited FOV (voxel sizes of 0.076, 0.100 and 0.200 mm). The IRR volumes were calculated using the Dolphin(®) software. Volumetric measurements were validated using IRR silicone putty casts. The analysis of variance (anova) for randomized block design complemented with the Tukey's test was employed.

RESULTS

IRR volumes obtained using voxel sizes of 0.200 and 0.250 mm were similar (P > 0.05). However, both these values were significantly different from that obtained using the 0.300-mm voxel (P < 0.05). There was no significant difference between IRR volumes measured through voxel sizes of 0.076 and 0.100 mm (P > 0.05), but both differed significantly from that obtained through the 0.200-mm voxel (P < 0.05). There was no significant difference between the volumetric measurements of the 0.200-mm voxel images of the restricted and large FOV protocols. The mean volumes of the silicone casts were smaller than those calculated using a 0.200-mm voxel, but were similar to those obtained using voxel sizes of 0.076 and 0.300 mm.

CONCLUSIONS

Despite the FOV protocol, voxel size can influence measurement of simulated IRR volumes. The importance of standardization of CBCT image acquisition protocols is emphasized, especially during follow-up of an IRR lesion, to prevent misinterpretation of its extent, which can create a bias in clinical decisions.