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

Quantitative and qualitative comparisons of pulp cavity volumes produced by cone beam computed tomography and micro-computed tomography through semiautomatic segmentation: An ex vivo investigation

OBJECTIVE

The aim of this study was to measure the volume and visually assess 3-dimensional (3D) virtual models of pulp cavities obtained through semiautomatic segmentation on images from 6 cone beam computed tomography (CBCT) units compared with the reference standard of micro-CT.

STUDY DESIGN

Fifteen mandibular premolar teeth were scanned with 6 CBCT units: Prexion 3D Elite, i-CAT Next Generation, NewTom 5G, Cranex 3D, 3Shape X1, and Orthophos SL 3D, using the smallest available field of view and highest resolution settings. Pulp cavity volumes were quantitatively assessed by 2 calibrated examiners. The volumes from each CBCT unit were compared with micro-CT. Qualitative assessment of the 3D reconstructions was also performed. Repeated-measures analysis of variance and the Friedman test compared the CBCT reconstructions to micro-CT. Intra- and interexaminer agreements were calculated with the intraclass correlation coefficient and kappa statistic.

RESULTS

The CBCT-based volumes were all significantly larger than micro-CT (P ≤ .0061). Prexion, X1, and Orthophos provided the segmentations that most closely resembled the reference standard. Intra- and interexaminer agreements ranged from good to excellent for quantitative measurements. Interexaminer agreement for qualitative evaluation was substantial.

CONCLUSIONS

Semiautomatic segmentation of CBCT images is a feasible method to produce virtual 3D models of the pulp cavity. Prexion, X1, and Orthophos were the CBCT units that resulted in 3D reconstructions most similar to the reference standard.

Evaluation of the follicular space volume of lower third molars with different impaction positions and angulations: A cone-beam computed tomography and histopathological study

Objective

To quantify the volume of the follicular spaces of impacted lower third molars (ILTMs) with different impaction positions and angulations using cone-beam computed tomography (CBCT) and to determine its association with the histopathological findings.

Study design

This study included 103 ILTMs of 33 men and 70 women aged 18-46 years (mean age, 29.18 years). The follicular space volumes were measured on CBCT by manual segmentation and correlated with the histopathological diagnosis of each ILTM having different impaction positions and angulations. Statistical Product and Service Solutions, version 24, was used for statistical analyses by applying the t-test and binary logistic regression and multiple linear regression tests (p < 0.05).

Results

Overall, 83 (80.6%) dental follicles presented a non-pathological diagnosis (mean follicular volume, 0.10 cm³), whereas 20 (19.4%) presented a pathological diagnosis (mean follicular volume, 0.32 cm³; p = 0.001). Similarly, the impaction depth in Position C cases was associated with a pathological diagnosis (p = 0.010).

Conclusion

The follicular volume of the ILTMs varied significantly in teeth with a histopathological diagnosis of a follicular cyst and was associated with the impaction depth, mainly in Position C cases, and its relationship with the mandibular ramus. A mean follicular volume of 0.32 cm³ was associated with a greater probability of a pathological diagnosis.

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.

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.

Influence of Voxel Size on CBCT Images for Dental Implants Planning

Objective  This study was developed to evaluate the influence of voxel size on bone measurements for implant planning.

Materials and Methods  The research was performed by using edentulous synthetic human mandibles with different levels of bone resorption. For each mandible, height and bone thickness were measured with a digital caliper. The PaX-i3d device was used to acquire the volumes of the five mandibles, with 50kVp, 4 mA, and a voxel size of 0.08 mm. After the acquisition, the images were reconstructed in the software CS three-dimensional Imaging, with four different sizes of voxels: 0.1, 0.2, 0.3, and 0.4 mm. All volumes were analyzed by a single evaluator who performed measurements to obtain bone height and thickness, using the reference points that were considered in obtaining the gold standard. The data were analyzed by ANOVA with a significance level of 5%.

Results  There was no significant difference in the measurements obtained with different voxel sizes, both for bone height measurements and bone thickness. There was no statistically significant difference in measurements in thickness in comparison to the gold standard.

Conclusion  When necessary, to measure height and bone thickness, it is possible to recommend voxel images of larger size (0.40 mm) without compromising the quality of the patient's clinical planning.

Management of internal inflammatory root resorption using injectable platelet-rich fibrin revascularization technique: a clinical study with cone-beam computed tomography evaluation

OBJECTIVES

The current study evaluated clinically and radiographically the management of internal inflammatory root resorption (IIRR) in permanent anterior teeth with or without periapical lesions using injectable platelet-rich fibrin (i-PRF) regenerative approach.

METHODS

Ten systemically healthy patients, with thirteen anterior mature teeth diagnosed with IIRR were selected for the study. At the first visit, the tooth was anesthetized, access cavity opened, root canals were mechanically prepared then medicated with calcium hydroxide and temporarily sealed. After 2-4 weeks, regenerative endodontic procedures were performed by preparing and applying i-PRF inside the canal, then a freshly prepared PRF membrane was placed over it. White mineral trioxide aggregate was placed over the PRF matrix, and the tooth was restored with a glass ionomer cement base and resin composite restoration. The patients were recalled for clinical and radiographic evaluation and follow-up every 3 months for 12 months. Cone-beam computed tomography (CBCT) imaging was performed preoperatively and after 12 months.

RESULTS

Clinical evaluation results showed resolution of signs and symptoms through the follow-up period in all of the cases. Both CBCT imaging readings of IIRR lesions and periapical lesions revealed a volumetric significant difference (p = 0.00) between the preoperative and the 12-month follow-up period.

CONCLUSIONS

Usage of i-PRF could arrest and allow for healing of IIRR in permanent mature teeth and allow for periapical healing with successful clinical results.

CLINICAL RELEVANCE

i-PRF revascularization technique proved to be a successful REP in the treatment of the IIRR, reducing the number of appointments and increasing patient compliance.

Influence of voxel size on cone beam computed tomography artifacts arising from the exomass

OBJECTIVES

The objective of this study was to evaluate the influence of voxel size on artifacts arising from the exomass in cone beam computed tomography (CBCT).

STUDY DESIGN

An imaging phantom was scanned using 2 CBCT units, each adjusted to 2 voxel sizes: 0.2 and 0.3 mm. From 1 to 3 metal inserts of titanium, cobalt-chromium, or amalgam were placed in the exomass and additional CBCT scans were acquired. Mean voxel gray values were obtained from 16 homogeneous areas of the phantom and averaged, and the standard deviation was calculated to obtain voxel gray value variability. The data were analyzed using 2-way analysis of variance, Tukey, and Dunnett tests (α =.05).

RESULTS

Overall, mean voxel gray values and voxel gray value variability did not differ significantly between CBCT scans obtained with voxel sizes of 0.2 and 0.3 mm for either CBCT model tested (P > .05). Despite some exceptions in which significant differences were observed between the 2 voxel sizes (P < .05), the mean voxel gray values and voxel gray value variability resulting from different metal compositions and, in most situations, for different numbers of metal inserts in the exomass were not affected.

CONCLUSION

Voxel size has little influence on exomass-related CBCT artifacts.

Relationship between buccal alveolar bone thickness and crown-to-root dimensions around mandibular first and second molars: A cone-beam-computed tomography-based study

BACKGROUND

Assessment of buccal alveolar bone thickness (ABT) and crown-to-root dimensions are essential in implant density; therefore, three-dimensional evaluation of these parameters provides a superior visualization than conventional radiographs.

OBJECTIVE

The present cross-sectional cohort study aims to investigate the relationship between buccal ABT and crown-to-root dimensions around the mandibular first and second molars using cone-beam-computed tomography (CBCT).

METHODS

Initially, CBCT-based scans from 271 individuals were assessed. Based on the inclusion and exclusion criteria, 171 CBCT-based scans were excluded. In total, 100 CBCT-scans were included in the present investigation and processed for data extraction. On the mandibular first and second molars, the mesial and distal root lengths and mesiodistal diameter of the crowns were measured. The pulpal floor served as a reference point for assessment of root length. The buccal ABT was measured at the coronal, middle and apical one-third of the root. Statistical analysis was performed and the level of significance was set at P< 0.01. One-hundred CBCT-scans from 294 mandibular teeth (137 first molars and 157 second molars) were included. One hundred and eighty-nine and 105 teeth were from males and females, respectively.

RESULTS

The normality plot showed a normal data distribution. The mesiodistal crown width showed a weak yet significant correlation with mesial root length (r= 0.137), bone thickness at mesial apical third (r= 0.180), distal apical (r= 0.157) and distal coronal third (r= 0.161). Bone thickness at mesial, middle and apical third correlated significantly with one other (r= 0.786).

CONCLUSION

There is a direct correlation between the buccal ABT and tooth dimensions around the mandibular first and second molars.

Negligible tooth resorptions after anterior open bite treatment using skeletal anchorage with miniplates

Introduction:

When miniplates are used as anchoring for orthodontic mechanics for anterior open bite correction by retraction of anterior teeth and posterior teeth intrusion and retraction, orthodontically induced inflammatory external apical root resorption is clinically negligible.

Methods:

A homogeneous sample of 32 patients was used, and the roots of the teeth were compared on CT scans performed before and after orthodontic treatment.

Results:

The observed root resorption was minimal, and this can be explained by the uniform distribution of forces in several teeth, simultaneously, in the set of the dental arch and in the bone that supports the teeth.

Conclusion:

The most important thing to prevent root resorption in orthodontic practice, besides being concerned with the intensity of the applied forces, is to be careful with its distribution along the roots of each tooth, in the dental arch and in the bone that supports the teeth.

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.

The crucial role of imaging in digital dentistry

One of the recent trends in dentistry - and this in every field from the restorative to the orthodontic one- is the introduction of simplified completely digital workflows. Digital dentistry is supposed to allow dentists to work more efficiently, and this at higher precision, and with the possibility of all-in-one sessions using in-house computerized techniques. In this workflow, one of the major tools for simulating and transferring dental treatments is imaging. Both 3D low dose radiographic as well as optical imaging are playing crucial roles and have been overwhelming the market. Novel design platforms, compact and extremely fast milling and printing units are now also plentiful and rapidly being adopted in practice. Nevertheless, many of the steps in this digital dentistry process, no matter how simplified, present risks that can contribute to reduced precision and clinical difficulties. It is therefore the purpose of the article to briefly describe the role of imaging in this digital workflow, and where the pitfalls can be found that may lead to errors and imprecision.

CBCT assessment of bone thickness in maxillary and mandibular teeth: an anatomic study

OBJECTIVE

The site of the sinus tract depends on the rate of resistance against abscess exudate drainage, bone morphology, and distance from the root apex to the outer cortical bone. To assess apical bone thickness in buccal and palatal/lingual aspects of maxillary and mandibular teeth, using a high-resolution cone-beam computed tomography (CBCT) system.

METHODOLOGY

In total, 422 CBCT examinations were included in the study, resulting in a sample of 1400 teeth. The scans were acquired by PreXion 3D, with a high-resolution protocol. The bone thickness was taken as the distance between the center of the apical foramen and the buccal and lingual/palatal cortical bone. The quantitative variables were expressed as mean values±standard deviation. The independent samples were analyzed using the t-test or the Mann-Whitney test (p<0.05).

RESULTS

The lowest mean value of bone thickness was observed in the buccal cortical bone of the upper canines (1.49 mm±0.86) and in the upper central incisors (1.59 mm±0.67). In premolar teeth, the lowest values were found in the buccal cortical bone of upper first premolars (1.13 mm±0.68). In the posterior teeth, the lowest values were found in the buccal cortical bone of upper first molars (1.98 mm±1.33). In the lower second molar region, the buccal cortical bone (8.36 mm±1.84) was thicker than the lingual cortical bone (2.95 mm±1.16) (p<0.05).

CONCLUSIONS

The lowest mean values of bone thickness are in the buccal cortical bone of the maxillary teeth. In the mandible, bone thickness is thinner in the buccal bone around the anterior and premolar teeth, and in the lingual aspect of mandibular molars. All these anatomic characteristics could make the occurrence of the sinus tract more susceptible in these specific regions of the maxillary and mandibular alveolar bone.

Accuracy of computer-assisted image analysis in the diagnosis of maxillofacial radiolucent lesions: A systematic review and meta-analysis

OBJECTIVES

This study aimed to search for scientific evidence concerning the accuracy of computer-assisted analysis for diagnosing maxillofacial radiolucent lesions.

METHODS

A systematic review was conducted according to the statements of Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocols and considering 10 databases, including the gray literature. Protocol was registered at the International Prospective Register of Systematic Reviews (CRD42018089945). The population, intervention, comparison and outcome strategy was used to define the eligibility criteria and only diagnostic test studies were included. Their risk of bias was assessed by the Joanna Briggs Institute Critical Appraisal tool. Random-effects model meta-analysis was performed and heterogeneity among the included studies was estimated using the I² statistic. The grade of recommendation, assessment, development, and evaluation (GRADE) tool assessed the quality of evidence and strength of recommendation across included studies.

RESULTS

Out of 715 identified citations, four papers, published between 2009 and 2017, fulfilled the criteria and were included in this systematic review. A total of 191 lesions, classified as periapical granuloma and cyst, dentigerous cyst or keratocystic odontogenic tumor, were analyzed. All selected articles scored low risk of bias. The pooled accuracy estimation, regardless of the classification method used, was 88.75% (95% CI = 85.19-92.30). Heterogeneity test reached moderate values (I² = 57.89%). According to the GRADE tool, the analyzed outcome was classified as having low level of certainty.

CONCLUSIONS

The overall evaluation showed all studies presented high accuracy rates of computer-aided diagnosis systems in classifying radiolucent maxillofacial lesions compared to histopathological biopsy. However, due to the moderate heterogeneity found among the studies included in this meta-analysis, a pragmatic recommendation about the use of computer-assisted analysis is not possible.

Comparison of in situ cone beam computed tomography scan data with ex vivo optical scan data in the measurement of root surface area

OBJECTIVE

The aim of this study was to compare root surface area (RSA) measurements of single-root teeth in a sheep mandible based on cone beam computed tomography (CBCT) with measurements made with an optical scanner.

STUDY DESIGN

Eight anterior teeth of a sheep cadaver mandible were scanned in situ by using CBCT with 3 different exposure parameters, followed by treatment with smoothing software. The teeth were then extracted and scanned individually with an optical scanner. Three-dimensional digital models of the teeth were reconstructed on the basis of CBCT and optical scanner data. RSA data were calculated, and an equivalence test was used to statistically compare the measurements with significance of difference established at α = 0.05.

RESULTS

The means of the differences between RSA measurements from CBCT and optical scanning ranged from 0.33% to 3.01%. There were no statistically significant differences between the 2 methods. The smoothing parameters for good fitness of the linear regression were determined to be 0.8 for the smooth factor, 8 for iterations, and 0 for compensate shrinkage.

CONCLUSIONS

The proposed CBCT technique to measure RSA is feasible. RSA data obtained from CBCT in situ are as accurate as optical scanner measurements ex vivo.

Age and sex estimation based on pulp cavity volume using cone beam computed tomography: development and validation of formulas in a Brazilian sample

OBJECTIVES

To develop and validate formulas for age and sex estimation based on the pulp cavity volume of teeth using cone beam CT.

METHODS

The sample was composed of 116 cone beam CT scans from Brazilian individuals of both sexes, ranging in age from 13 to 70 years. A total of 232 teeth (upper central incisors and canines) were evaluated. Two calibrated examiners determined pulp cavity volumes using the ITK-SNAP software. Pearson's correlation test was used to assess the correlation between chronological age and pulp volume. Linear and logistic regression models were developed for age and sex estimation, respectively, and were validated in another sample of 72 teeth.

RESULTS

Pearson's correlation coefficients between age and pulp volume were negative and significant (p < 0.0001) for both teeth (r = -0.8782 for central incisors and r = -0.8738 for canines). The age estimation formulas showed good determination coefficients (adjusted R² = 0.7614 to 0.8367). For sex estimation, when the age was known, the coefficients were also good (adjusted R² = 0.649 to 0.812). However, when the age was unknown, the coefficients of the sex estimation formulas were low (adjusted R² = 0.047 to 0.393). Validation showed high accuracy of age estimation in individuals older than 35 years, as well as high accuracy of sex estimation when the age was known.

CONCLUSIONS

Our formulas provided excellent results and can be applied to the Brazilian population. The best results were observed for age estimation in females and for sex estimation when the age was known.