Differentiation of periapical granulomas and cysts by using dental MRI: a pilot study

In vivo assessment of artefacts in MRI images caused by conventional twistflex and various fixed orthodontic CAD/CAM retainers

PURPOSE

To assess magnetic resonance imaging (MRI) artefacts caused by different computer-aided design/computer-aided manufacturing (CAD/CAM) retainers in comparison with conventional hand bent stainless steel twistflex retainers in vivo.

MATERIALS AND METHODS

MRI scans (3 Tesla) were performed on a male volunteer with different CAD/CAM retainers (cobalt-chromium, CoCr; nickel-titanium, NiTi; grade 5 titanium, Ti5) and twistflex retainers inserted. A total of 126 landmarks inside and outside the retainer area (RA; from canine to canine) were evaluated by two blinded radiologists using an established five-point visibility scoring (1: excellent, 2: good, 3: moderate, 4: poor, 5: not visible). Friedman and two-tailed Wilcoxon tests were used for statistical analysis (significance level: p < 0.05).

RESULTS

Twistflex retainers had the strongest impact on the visibility of all landmarks inside (4.0 ± 1.5) and outside the RA (1.7 ± 1.2). In contrast, artefacts caused by CAD/CAM retainers were limited to the dental area inside the RA (CoCr: 2.2 ± 1.2) or did not impair MRI-based diagnostics in a clinically relevant way (NiTi: 1.0 ± 0.1; Ti5: 1.4 ± 0.6).

CONCLUSION

The present study on a single test person demonstrates that conventional stainless steel twistflex retainers can severely impair the diagnostic value in head/neck and dental MRI. By contrast, CoCr CAD/CAM retainers can cause artefacts which only slightly impair dental MRI but not head/neck MRI, whereas NiTi and Ti5 CAD/CAM might be fully compatible with both head/neck and dental MRI.

The Effect of Lasers on the Healing of Periapical Lesion: A Systematic Review

Introduction: Endodontic treatment of teeth with periapical lesions presents more clinical difficulty. Various lasers in several methods are used in endodontics, and most of them are utilized as an adjunctive protocol in order to reduce the bacterial load of the root canal system. Improved disinfection plays a crucial role in enhanced and accelerated healing of periapical lesions. This review aims to summarize studies assessing the effect of lasers on periapical lesion healing. Methods: PubMed/MEDLINE, Scopus, Embase, and Web of Science (ISI) online databases were searched, with no publication year or status restriction, for relevant articles on April 2023. Clinical studies evaluating the effect of laser application on the periapical lesion of patients using radiographic assessment were considered eligible for inclusion. Results: Eight studies were included after carefully screening the obtained articles, first by their title and abstract and then by their full texts. Diode (4), Er, Cr: YSGG (3), and Nd: YAG (1) lasers were used with output powers that varied from 0.75 to 2 watts. Photodynamic therapy was employed in two studies, and in other studies, the root canal system was directly irradiated. Irradiation of the root canal system was adjunctive to standard preparation in all studies. The healing of the teeth treated with lasers was not inferior to those conventionally treated. In all of the included studies, laser application outperformed the standard cleaning and shaping protocol; however, this improved or faster healing was not statistically significant in most studies. Conclusion: Lasers might expedite and improve the healing process of periapical lesions. Since lasers enhance the quality of cleaning of the root canal system, it is hard to point out the exact mechanism of it. Further investigations are needed to realize the effectiveness of this treatment modality and to discover the underlying biological concepts.

Comparative Analysis of Examination Methods for Periapical Lesion Diagnostics: Assessing Cone-Beam Computer Tomography, Ultrasound, and Periapical Radiography

INTRODUCTION

Periapical lesions of teeth are typically evaluated using periapical X-rays (PA) or cone-beam computer tomography (CBCT); however, ultrasound imaging (US) can also be used to detect bone defects. A comparative analysis is necessary to establish the diagnostic accuracy of US for the detection of periapical lesions in comparison with PA and CBCT.

OBJECTIVES

This study aimed to evaluate and compare the measurement precision of US against PA and CBCT in detecting periapical lesions.

METHODS

This study included 43 maxillary and mandibular teeth with periapical lesions. All teeth were examined clinically, radiographically, and ultrasonographically. Observers evaluated and measured the periapical lesions on CBCT, PA, and US images.

RESULTS

The comparison of lesion size showed that it differs significantly between the different methods of examination. A statistically significant difference was found between CBCT and US (mean difference = 0.99 mm, 95% CI [0.43-1.55]), as well as between CBCT and PA (mean difference = 0.61 mm, 95% CI [0.17-1.05]). No difference was found between the US and PA methods (p = 0.193).

CONCLUSION

US cannot replace PA radiography in detecting pathologies but it can accurately measure and characterize periapical lesions with minimal radiation exposure. CBCT is the most precise and radiation-intensive method so it should only be used for complex cases.

Accuracy of Magnetic Resonance Imaging in Clinical Endodontic Applications: A Systematic Review

INTRODUCTION

The development of dedicated coils and new magnetic resonance imaging (MRI) sequences has led to an increase in image resolution and a reduction in artifacts. Consequently, numerous studies have demonstrated the utility of MRI as a nonionizing alternative to cone-beam computed tomographic imaging. The aim of this systematic review was to evaluate the accuracy of MRI in clinical applications in endodontics.

METHODS

A literature search was conducted using PubMed, Embase, Scopus, and Web of Science. The inclusion criteria encompassed studies evaluating MRI applications in endodontics, covering tooth and root canal anatomy, root canal working length, pulp vitality and regeneration, the effect of caries on dental pulp, guided endodontics, periapical lesions, and root cracks/fractures. The selected studies examined both ex vivo and in vivo human teeth using clinical MRI units. Two researchers independently screened the studies, applied the eligibility criteria, and assessed the potential risk of bias using the revised QUADAS-2 tool (Bristol Medical School, University of Bristol, UK).

RESULTS

A total of 18 studies were included in this systematic review, demonstrating that the use of MRI has a high diagnostic value in endodontics. In the evaluation of tooth and root canal anatomy, pulp vitality and regeneration, the effect of caries on dental pulp, periapical lesions, and root cracks/fractures, MRI's accuracy is comparable to or even higher than reference standards such as cone-beam computed tomographic imaging, micro-computed tomographic imaging, and histology.

CONCLUSIONS

MRI has high potential accuracy for diagnosing various clinical endodontic tasks, except for root canal length, size of caries, and periapical lesion dimensions, which are overestimated in MRI.

Dental-dedicated MRI, a novel approach for dentomaxillofacial diagnostic imaging: technical specifications and feasibility

MRI is a noninvasive, ionizing radiation-free imaging modality that has become an indispensable medical diagnostic method. The literature suggests MRI as a potential diagnostic modality in dentomaxillofacial radiology. However, current MRI equipment is designed for medical imaging (eg, brain and body imaging), with general-purpose use in radiology. Hence, it appears expensive for dentists to purchase and maintain, besides being complex to operate. In recent years, MRI has entered some areas of dentistry and has reached a point in which it can be provided following a tailored approach. This technical report introduces a dental-dedicated MRI (ddMRI) system, describing how MRI can be adapted to fit dentomaxillofacial radiology through the appropriate choice of field strength, dental radiofrequency surface coil, and pulse sequences. Also, this technical report illustrates the possible application and feasibility of the suggested ddMRI system in some relevant diagnostic tasks in dentistry. Based on the presented cases, it is fair to consider the suggested ddMRI system as a feasible approach to introducing MRI to dentists and dentomaxillofacial radiology specialists. Further studies are needed to clarify the diagnostic accuracy of ddMRI considering the various diagnostic tasks relevant to the practice of dentistry.

Diagnosis of Odontogenic Maxillary Sinusitis by Cone-beam Computed Tomography: A Critical Review

INTRODUCTION

This review aims to provide an up-to-date overview of the current applications of cone-beam computed tomography (CBCT) and other imaging modalities in diagnosing odontogenic maxillary sinusitis (OMS). Furthermore, the clinical operation procedures of radiography modalities in OMS diagnosis were summarized, with the goal of assisting clinicians in improving OMS diagnostic accuracy in clinical practice.

METHOD

A comprehensive review of researches that discussed the applications of radiography modalities in the diagnosis of OMS was conducted. Pertinent information was evaluated and organized for this review.

RESULTS

Cone-beam computed tomography (CBCT) offers a superior, high-resolution, and three-dimensional view of the maxillary tooth-bone-sinus complex compared to conventional radiography modalities. It enables a better understanding and classification of the spatial relationships between root apices/periapical lesions and maxillary sinus. The use of CBCT, combined with the advantages of other radiography modalities and proper image interpretation, is indispensable to enhance OMS diagnostic accuracy and mitigate the risk of missed or misdiagnosis.

CONCLUSION

The significance of CBCT in the diagnosis of oral and maxillofacial conditions has garnered widespread recognition. It provides highly precise diagnostic information and classification basis for OMS. The clinical operation procedures for imaging examination are essential in ensuring the consistency and reliability of the diagnosis.

Human Periapical Odontogenic Granulomas: Aspects of Microvessel Density (MVD), Heterogeneity of Blood Vessels and Mast Cells Density (MCD)

Periapical odontogenic granulomas are among the most encountered pathology that involve the alveolar bone, with severe consequences such as bone resorption, the presence of inflammatory infiltrate and the formation of abnormal vascularization. The present study aimed to quantify the existence of the microvessel density (MVD), mast cell density (MCD) and heterogeneity of the encountered blood vessels. A total of 37 patients diagnosed with odontogenic periapical granulomas were included, and the gender distribution, age and localization of the pathological lesions was assessed. After the surgical removal of the periapical odontogenic granuloma, the collected tissue was fixed in 10% buffered formalin. Primary processing, morphological analysis and immunohistochemical staining was performed in order to characterize the altered tissue. The results outlined the presence of a high number of mast cells, especially in the area of the inflamed tissue; the high heterogeneity of the blood vessels; and increased MVD with positive CD34. The conclusions of the study focus on the key role of the mast cells and their implication in the initiation and development of the angiogenesis process, triggering the inflammatory response of the host. Nevertheless, periapical odontogenic granulomas develop as an inflammatory response to the interaction between the host's immune system and microbial invasion.

Efficacy of imaging techniques for the diagnosis of apical periodontitis: A systematic review

BACKGROUND

Apical periodontitis (AP) is a chronic inflammatory response of microbial aetiology. Pathological changes associated with AP may not be visible on radiographic images and may linger without causing any symptoms. Clinicians rely mostly on clinical examination and imaging techniques to establish a diagnosis.

OBJECTIVES

The aim of this review was to answer the following question using the PICO format: In the adult human permanent dentition (P), what is the efficacy of diagnostic imaging of the periapical tissues (I) using histopathology as a reference standard (C) in the diagnosis of apical periodontitis, in terms of diagnostic accuracy (O).

METHODS

MEDLINE, EMBASE, Scopus and Cochrane Library were searched for English articles published through October 2021. At least two independent reviewers evaluated the study design, imaging modality used, histopathological assessment, outcome measures, results and conclusions for each article. The risk of bias was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2.

RESULTS

The initial search strategy identified 544 articles. Seven articles were included for analysis in the final review, all of which involved tissue samples obtained from cadavers. No clinical studies were identified that met the eligibility criteria. A consistently low sensitivity score and negative predictive value were reported for periapical radiography, especially in comparison to CBCT, which scored highly. Both modalities achieved high scores for specificity and positive predictive value. Diagnostic accuracy of CBCT was lower for root-filled teeth in comparison to non-root-filled teeth.

DISCUSSION

Assessment of the periapical tissues using periapical radiographs was shown to have a low to moderate agreement with the histopathological assessment. CBCT was reported to be more accurate than PR and demonstrated a good agreement with histopathology, especially for non-root-filled teeth.

CONCLUSIONS

This review identified a need for greater standardization in methodology and reporting, and as the findings are based on cadaver studies, their clinical relevance must be interpreted with caution.

REGISTRATION

PROSPERO (CRD42021272147).

Association between Clinical/Radiographic Characteristics and Histopathological Diagnoses of Periapical Granuloma and Cyst

OBJECTIVE

 The aim of this study was to determine the association between clinical/radiographic characteristics and histopathological diagnoses of periapical granuloma and cyst obtained from the teeth treated with endodontic microsurgery.

MATERIALS AND METHODS

 The clinical, radiographic (periapical and cone-beam computed tomography), and histopathological data were collected from patients' dental records of endodontic microsurgery on the teeth with periapical lesions. These lesions were histopathologically diagnosed as either granuloma or cyst, at the Endodontic Clinic, Faculty of Dentistry, Mahidol University, Bangkok, Thailand, from 2016 to 2021 according to inclusion and exclusion criteria. The data were analyzed using bivariate analysis and a multinomial logistic regression at a significance level of p-value less than 0.05.

RESULTS

 A total of 83 patients (58 females and 25 males) with an average age of 45 to 49.5 years old met the criteria including 68 periapical granulomas (81.9%) and 15 periapical cysts (18.1%). A periapical lesion involving multiple teeth in a periapical radiograph was significantly associated with the histopathological diagnosis of periapical cyst (p < 0.05). Such periapical lesion was six times more likely to be periapical cyst than periapical granuloma.

CONCLUSIONS

 A significant factor for predicting periapical cyst from periapical granuloma was the presence of a periapical lesion with multiple-teeth involvement in a dental radiograph.

Evaluation of 3D MRI for early detection of bone edema associated with apical periodontitis

OBJECTIVES

To detect and evaluate early signs of apical periodontitis using MRI based on a 3D short-tau-inversion-recovery (STIR) sequence compared to conventional panoramic radiography (OPT) and periapical radiographs in patients with apical periodontitis.

MATERIALS AND METHODS

Patients with clinical evidence of periodontal disease were enrolled prospectively and received OPT as well as MRI of the viscerocranium including a 3D-STIR sequence. The MRI sequences were assessed for the occurrence and extent of bone changes associated with apical periodontitis including bone edema, periradicular cysts, and dental granulomas. OPTs and intraoral periapical radiographs, if available, were assessed for corresponding periapical radiolucencies using the periapical index (PAI).

RESULTS

In total, 232 teeth of 37 patients (mean age 62±13.9 years, 18 women) were assessed. In 69 cases reactive bone edema was detected on MRI with corresponding radiolucency according to OPT. In 105 cases edema was detected without corresponding radiolucency on OPT. The overall extent of edema measured on MRI was significantly larger compared to the radiolucency on OPT (mean: STIR 2.4±1.4 mm, dental radiograph 1.3±1.2 mm, OPT 0.8±1.1 mm, P=0.01). The overall PAI score was significantly higher on MRI compared to OPT (mean PAI: STIR 1.9±0.7, dental radiograph 1.3±0.5, OPT 1.2±0.7, P=0.02).

CONCLUSION

Early detection and assessment of bone changes of apical periodontitis using MRI was feasible while the extent of bone edema measured on MRI exceeded the radiolucencies measured on OPT.

CLINICAL RELEVANCE

In clinical routine, dental MRI might be useful for early detection and assessment of apical periodontitis before irreversible bone loss is detected on conventional panoramic and intraoral periapical radiographs.

Diagnostic compatibility of various fixed orthodontic retainers for head/neck MRI and dental MRI

OBJECTIVES

To evaluate the diagnostic MRI compatibility of different fixed orthodontic retainers using a high-resolution 3D-sequence optimized for artifact reduction.

MATERIALS AND METHODS

Maxillary and mandibular retainers made of five different materials were scanned in vitro and in vivo at 3 T MRI using an MSVAT-SPACE sequence. In vitro, artifact volumes were determined for all maxillary and mandibular retainers (AVmax; AVmand). In vivo, two independent observers quantified the extent of artifacts based on the visibility of 124 dental and non-dental landmarks using a five-point rating scale (1 = excellent, 2 = good, 3 = acceptable, 4 = poor, 5 = not visible).

RESULTS

Rectangular-steel retainers caused the largest artifacts (AVmax/AVmand: 18,060/15,879 mm3) and considerable diagnostic impairment in vivo (mean landmark visibility score ± SD inside/outside the retainer areas: 4.8 ± 0.8/2.9 ± 1.6). Smaller, but diagnostically relevant artifacts were observed for twistflex steel retainers (437/6317 mm3, 3.1 ± 1.7/1.3 ± 0.7). All retainers made of precious-alloy materials produced only very small artifact volumes (titanium grade 1: 70/46 mm3, titanium grade 5: 47/35 mm3, gold: 23/21 mm3) without any impact on image quality in vivo (each retainer: visibility scores of 1.0 ± 0.0 for all landmarks inside and outside the retainer areas).

CONCLUSIONS

In contrast to steel retainers, titanium and gold retainers are fully compatible for both head/neck and dental MRI when using MSVAT-SPACE.

CLINICAL RELEVANCE

This study demonstrates that titanium and gold retainers do not impair the diagnostic quality of head/neck and dental MRI when applying an appropriate artifact-reduction technique. Steel retainers, however, are not suitable for dental MRI and can severely impair image quality in head/neck MRI of the oral cavity.

Dental MRI-only a future vision or standard of care? A literature review on current indications and applications of MRI in dentistry

MRI is increasingly used as a diagnostic tool for visualising the dentoalveolar complex. A comprehensive review of the current indications and applications of MRI in the dental specialities of orthodontics (I), endodontics (II), prosthodontics (III), periodontics (IV), and oral surgery (V), pediatric dentistry (VI), operative dentistry is still missing and is therefore provided by the present work.The current literature on dental MRI shows that it is used for cephalometry in orthodontics and dentofacial orthopaedics, detection of dental pulp inflammation, characterisation of periapical and marginal periodontal pathologies of teeth, caries detection, and identification of the inferior alveolar nerve, impacted teeth and dentofacial anatomy for dental implant planning, respectively. Specific protocols regarding the miniature anatomy of the dentofacial complex, the presence of hard tissues, and foreign body restorations are used along with dedicated coils for the improved image quality of the facial skull.Dental MRI poses a clinically useful radiation-free imaging tool for visualising the dentoalveolar complex across dental specialities when respecting the indications and limitations.

The magnetic resonance imaging characteristics of radicular cysts and granulomas

OBJECTIVES

Limited studies have differentiated radicular cysts and granulomas with MRI. Therefore, we investigated the MRI characteristics of the two lesions and clarified features for distinguishing between them.

METHODS

We collected data of 27 radicular cysts and 9 granulomas definitively diagnosed by histopathology and reviewed the fat-saturated T2 weighted, T1 weighted, and contrast-enhanced fat-saturated T1 weighted images. We measured the maximum diameter and apparent diffusion coefficient values of the lesions. We employed Fisher's exact test, the Mann-Whitney U test, and independent t-tests to compare the two lesions and created a decision tree for discriminating between them.

RESULTS

There were significant differences between radicular cysts and granulomas with respect to five imaging characteristics-signal intensity of the lesion centre on fat-saturated T2 weighted images; signal intensity, texture, and contrast enhancement of the lesion centre on contrast-enhanced fat-saturated T1 weighted images; and maximum diameter of the lesion. The cut-off diameter for radicular cysts was 15.9 mm. The area under the receiver operating characteristic curve, sensitivity, and specificity were 0.971, 85.2%, and 100%, respectively.

CONCLUSIONS

From the decision tree analysis, maximum diameter, lesion centre contrast enhancement on contrast-enhanced fat-saturated T1 weighted images, and lesion centre signal intensity on fat-saturated T2 weighted images were important for discriminating between radicular cysts and granulomas.

Evaluation of CT and MRI Imaging Results of Radicular Cysts, Odontogenic Keratocysts, and Dentigerous Cysts and their Contribution to the Differential Diagnosis

AIM

This study aimed to evaluate the contribution of the MRI and CT results to the differential diagnosis of histopathologically different odontogenic cysts.

BACKGROUND

Odontogenic cysts are commonly seen in the jaw bone and their surgical operations have an important place in the practice of maxillofacial surgery; treatment options for these cysts differ according to their histopathology. Differential results that can be obtained from the radiological evaluations of different cyst groups will allow the surgeon to plan a more accurate approach at the beginning of the operation. In this study, computed tomography (CT) and magnetic resonance imaging (MRI) results of different cyst groups were interpreted together with their histopathological diagnosis.

METHODS

CT and MRI results of 17 patients aged between 19-61 were evaluated, whose histopathological diagnosis consisted of 3 radicular cysts (RC), a total of 9 odontogenic keratocysts (OKC) of which 4 were inflamed, and a total of 5 dentigerous cysts (DC) of which one of them was inflammatory.

RESULTS

In the CT scan, all cysts showed lytic, a sclerotic surrounding, and showed MRI peripheral enhancement, whereas solid nodular enhancement was only observed in OKCs. Edema and/or air in the surrounding bone medulla was observed in the infected lesions. OKC was heterogeneous, whereas RC and DC were more homogeneous. Diffusion restriction was observed to be frequent in OKCs. The OKCs were ellipsoidal in appearance and were located parallel to the long axis of the bone, and their dimensions were observed to be larger than the other cysts. OKCs may be accompanied by unerupted teeth. Radicular cysts were located perpendicular to the long axis of the bone and were globular in appearance, and their dimensions were smaller and more homogeneous compared to the OKCs. Dentigerous cysts are also accompanied by an unerupted tooth, and their peripheral enhancement is minimal and homogeneous. However, dentigerous cysts can be dense in content and smaller in size, and ellipsoidal localization is more common than OKCs.

CONCLUSION

In addition to classic panoramic radiography in the evaluation and differential diagnosis of maxillary and mandibular lesions, CT and MRI evaluations can provide helpful information to the surgeon and pathologist in making the diagnosis and may further help plan the operation.

High-Resolution Single Tooth MRI With an Inductively Coupled Intraoral Coil-Can MRI Compete With CBCT?

OBJECTIVES

The aims of this study were to quantify T1/T2-relaxation times of the dental pulp, develop a realistic tooth model, and compare image quality between cone-beam computed tomography (CBCT) and high-resolution magnetic resonance imaging (MRI) of single teeth using a wireless inductively coupled intraoral coil.

METHODS

T1/T2-relaxometry was performed at 3 T in 10 healthy volunteers (283 teeth) to determine relaxation times of healthy dental pulp and develop a realistic tooth model using extracted human teeth. Eight MRI sequences (DESS, CISS, TrueFISP, FLASH, SPACE, TSE, MSVAT-SPACE, and UTE) were optimized for clinically applicable high-resolution imaging of the dental pulp. In model, image quality of all sequences was assessed quantitatively (contrast-to-noise ratio) and qualitatively (visibility of anatomical structures and extent of susceptibility artifacts using a 5-point scoring scale). Cone-beam computed tomography served as the reference modality for qualitative assessment. Statistical analysis was performed using 2-way analysis of variance, Fisher exact test, and Cohen κ.

RESULTS

In vivo, relaxometry of dental pulps revealed T1/T2 relaxation times at 3 T of 738 ± 100/171 ± 36 milliseconds. For all sequences, an isotropic resolution of (0.21 mm) 3 was achieved, with acquisition times ranging from 6:19 to 8:02 minutes. In model, the highest contrast-to-noise ratio values were observed for UTE, followed by TSE and CISS. The best image/artifact quality, however, was found for DESS (mean ± SD: 1.3 ± 0.3/2.2 ± 0.0), FLASH (1.5 ± 0.3/2.4 ± 0.1), and CISS (1.5 ± 0.4/2.5 ± 0.1), at a level comparable to CBCT (1.2 ± 0.3/2.1 ± 0.1).

CONCLUSIONS

Optimized MRI protocols using an intraoral coil at 3 T can achieve an image quality comparable to reference modality CBCT within clinically applicable acquisition times. Overall, DESS revealed the best results, followed by FLASH and CISS.

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.

Reliability and accuracy of dental MRI for measuring root canal length of incisors and canines: a clinical pilot study

To evaluate whether high-resolution, non-contrast-enhanced dental MRI (dMRI) can reliably and accurately measure the canal length of incisors and canines compared with cone-beam computed tomography (CBCT). Three-Tesla dMRI was performed in 31 participants (mean age: 50.1 ± 14.2 years) with CBCT data. In total, 67 teeth were included (28 from the upper jaw and 39 from the lower jaw; 25 central incisors, 22 lateral incisors, and 20 canines). CBCT and dMRI datasets were reconstructed to visualize the root canal pathway in a single slice in the vestibulo-oral (V-O) and mesio-distal (M-D) direction. Root canal length was measured twice by two radiologists using dMRI and CBCT. Data were statistically analyzed by calculating intraclass correlation coefficients (ICCs) and performing Bland–Altman analysis. The reliability of dMRI measurements was excellent and comparable to that of CBCT measurements (intra-rater I/intra-rater II/inter-rater was 0.990/0.965/0.951 for dMRI vs. 0.990/0.994/0.992 for CBCT in the M-D direction and 0.991/0.956/0.967 for dMRI vs. 0.998/0.994/0.996 for CBCT in the V-O direction). According to Bland–Altman analysis, the mean (95% confidence interval) underestimation of root canal lengths was 0.67 mm (− 1.22 to 2.57) for dMRI and 0.87 mm (− 0.29 to 2.04) for CBCT in the M-D direction/V-O direction. In 92.5% of cases, dMRI measurements of canal length had an accuracy within 0–2 mm. Visualization and measurement of canal length in vivo using dMRI is feasible. The reliability of dMRI measurements was high and comparable to that of CBCT measurements. However, the spatial and temporal resolution of dMRI is lower than that of CBCT, which means dMRI measurements are less accurate than CBCT measurements. This means dMRI is currently unsuitable for measuring canal length in clinical practice.

Endodontic working length measurements of premolars and molars in high-resolution dental MRI: a clinical pilot study for assessment of reliability and accuracy

OBJECTIVES

To prospectively assess the reliability and accuracy of high-resolution, dental MRI (dMRI) for endodontic working length (WL) measurements of premolars and molars under clinical conditions.

MATERIALS AND METHODS

Three-Tesla dMRI was performed in 9 subjects who also had undergone cone-beam computed tomography (CBCT) (mean age: 47 ± 13.5 years). A total of 34 root canals from 12 molars (4/8, upper/lower jaw; 22 root canals) and 11 premolars (2/9 upper/lower jaw; 12 root canals) were included. CBCT and dMRI datasets were reconstructed to visualize the root canal in one single slice. Subsequently, two radiologists measured the root canal lengths in both modalities twice in blinded fashion. Reliability and accuracy for both modalities were assessed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis, respectively.

RESULTS

Reliability (intra-rater I/II; inter-rater) of dental MRI measurements was excellent and comparable to CBCT for premolars (0.993/0.900; 0.958 vs. 0.993/0.956; 0.951) and for molars (0.978/0.995; 0.986 vs. 0.992/0.996; 0.989). Bland-Altman analysis revealed a mean underestimation/bias (95% confidence interval) of dMRI measurements of 0.8 (- 1.44/3.05) mm for premolars and 0.4 (- 1.55/2.39) mm for molars. In up to 59% of the cases, the accuracy of dMRI for WL measurements was within the underestimation margin of 0 to 2 mm short of the apical foramen AF.

CONCLUSIONS

In vivo demonstration and measurement of WL are feasible using dMRI. The reliability of measurements is high and equivalent to CBCT. Nonetheless, due to lower spatial resolution and longer acquisition time, the accuracy of dMRI is inferior to CBCT, impeding its current use for clinical treatment planning.

CLINICAL RELEVANCE

dMRI is a promising radiation-free imaging technique. Its reliability for endodontic working length measurements is high, but its accuracy is not satisfactory enough yet.

Fibrous granulation mimicking cranial intraosseous tumor

A cranial intraosseous lesion is a rare disease with a limited number of subtypes. We report a case of a cranial intraosseous fibrous granulation that mimicked an intraosseous tumor. A 57-year-old man was incidentally found to have a cranial intraosseous lesion on brain computed tomography. Total resection was performed to establish a pathological diagnosis and to achieve cosmesis, and the pathological diagnosis was fibrosis and fibrous granulation in the medullary cavity. Fibrous granulation tissue occurs in the calvarium due to bone defects secondary to acquired factors, including trauma. Since its pathological diagnosis is established through surgery, surgery should be carefully considered based on the patient's chief complaint, location of the lesion, and suspicion of malignancy based on imaging findings.

Value of FDG-PET/MR in Oral Focus Assessment in Head and Neck Cancer Patients-A Feasibility Study

FDG-PET/MR is a hybrid imaging modality used for the staging and restaging of advanced head & neck cancer (HNC) patients. Their treatment typically involves radiation therapy, which requires previous dental focus assessment. The aim of this study was to analyze if staging FDG-PET/MR is a valuable tool for oral focus assessment. For this purpose, FDG-PET/MR findings, such as metabolic activity of periapical radiolucencies and marginal periodontitis, were retrospectively compared with conventional standardized dental focus assessment, including dental radiographs and clinical assessment of 124 teeth in seven patients. Increased FDG uptake of periapical lesions was found in one out of 23 lesions. Increased FDG uptake of the marginal periodontium was recorded in one out of 34 lesions. In summary, standardized dental focus assessment by panoramic radiography and periapical radiographs may be enriched by information from FDG-PET/MR, showing active inflammation in dental foci. However, many dental foci have no correlate in FDG-PET/MR. The treatment decision for oral foci may benefit from the visualized presence or absence of metabolic activity on FDG-PET/MR.

Inductively Coupled Intraoral Flexible Coil for Increased Visibility of Dental Root Canals in Magnetic Resonance Imaging

OBJECTIVES

Accurate visualization of dental root canals is vital for the correct diagnosis and subsequent treatment. This work assesses the improvement of a dedicated new coil for dental magnetic resonance imaging (MRI) in comparison to conventional ones in terms of signal-to-noise ratio (SNR) and visibility.

MATERIALS AND METHODS

A newly developed intraoral flexible coil was used to display dental roots with MRI, and it provides improved sensitivity with a loop design and size adjusted to a single tooth anatomy. Ex vivo and in vivo measurements were performed on a 3 T clinical MR system, and results were compared with conventional head and surface coil images. Additional comparison was performed with a modified fast spin echo sequence and a constructive interference in steady-state sequence.

RESULTS

Ex vivo, an SNR gain of 6.3 could be achieved with the intraoral flexible coil setup, and higher visibility down to 200 μm was possible, whereas the external loop coil is limited to 400 μm. In vivo measurements in a volunteer resulted in an SNR gain of up to 4.5 with an improved delineation of the root canals, especially for the branch tissue splitting of the mesial root canal into mesial-buccal and mesial-lingual.

CONCLUSIONS

In summary, we showed the feasibility of implementing a wireless coil approach with readily available dental practice materials for sealing and placement. Highly improved MRI scans can be acquired within clinically feasible scan times, and this might provide additional medical findings to supplement available x-ray images.

Interplay of collagen and mast cells in periapical granulomas and periapical cysts: a comparative polarizing microscopic and immunohistochemical study

Objectives

This pilot study aimed to establish the interrelationship between collagen and mast cells in periapical granulomas and periapical cysts.

Materials and Methods

An observational cross-sectional study was conducted on the paraffin-embedded tissue sections of 68 specimens (34 periapical granulomas and 34 periapical cysts). The specimens were stained with picrosirius to observe collagen fiber birefringence and anti-tryptase antibody to evaluate the mast cell count immunohistochemically. The mean number and birefringence of collagen fibers, as well as the mean number of mast cells (total, granulated, and degranulated), and the mean inflammatory cell density were calculated. The data obtained were analyzed using the Kruskal Wallis test, Mann Whitney U test, and Spearman correlation test (p < 0.05).

Results

The mean number of thick collagen fibers was higher in periapical cysts, while that of thin fibers was higher in granulomas (p = 0.00). Cysts emitted orange-yellow to red birefringence, whereas periapical granulomas had predominantly green fibers (p = 0.00). The mean inflammatory cell density was comparable in all groups (p = 0.129). The number of total, degranulated, and granulated mast cells exhibited significant results (p = 0.00) in both groups. Thick cyst fibers showed significant inverse correlations with inflammation and degranulated mast cells (p = 0.041, 0.04 respectively).

Conclusions

Mast cells and inflammatory cells influenced the nature of collagen fiber formation and its birefringence. This finding may assist in the prediction of the nature, pathogenesis, and biological behavior of periapical lesions.

Magnetic resonance imaging versus cone beam computed tomography in diagnosis of periapical pathosis – A systematic review

Objective

The diagnosis of any dental pathology can vary from being simple to challenging. While the use of cone beam computed tomography (CBCT) is well established, magnetic resonance imaging (MRI) remains a proof of concept. This systematic review aims to compare the diagnostic ability of MRI with CBCT in diagnosing periapical pathosis.

Materials and Methods

This systematic search was performed using the electronic databases of MEDLINE, Cochrane Library, Google Scholar, and Science Direct to identify relevant articles from 2010 to 2020. The search terms used were magnetic resonance imaging, cone beam computed tomography, diagnosis, and periapical diseases.

Result

In total, 3218 potentially relevant abstracts and titles were identified. After removing duplicates, 1288 articles were reviewed for titles and abstracts, and 29 articles were selected for full-text reading. From those, 19 articles were finally selected that included original research studies, case reports, and case series and were included for systematic review. Most of the studies included in this review suggested that the combined use of CBCT and MRI is needed for a better and more precise diagnosis of complex periapical pathoses. The main advantage of MRI is its ability to image soft tissues usingnonionizing radiation, and the main disadvantage in the case of CBCT is overdiagnosis of the lesion.

Conclusion

MRI has various advantages over CBCT with similar diagnostic utility. When diagnosing periapical pathogens, both MRI and CBCT are needed for an accurate diagnosis.

Quantitative assessment of contrast-enhancement patterns of the healthy dental pulp by magnetic resonance imaging: A prospective in vivo study

AIM

This prospective in vivo study aimed to optimize the assessment of pulpal contrast-enhancement (PCE) on dental magnetic resonance imaging (dMRI) and investigate physiological PCE patterns.

METHODOLOGY

In 70 study participants, 1585 healthy teeth were examined using 3-Tesla dMRI before and after contrast agent administration. For all teeth, the quotient of post- and pre-contrast pulp signal intensity (Q-PSI) was calculated to quantify PCE. First, pulp chambers were analysed in 10 participants to compare the coefficient of variation of mean versus maximum Q-PSI values (Q-PSI_mean versus Q-PSI_max ). Second, dynamic PCE was evaluated in 10 subjects to optimize the time interval between contrast agent application and image acquisition. Finally, 50 participants (age groups: 20-29, 30-39, 40-49, 50-59 and 60-69 years) were examined to analyse age, gender, tooth types and maxilla versus mandible as independent factors of PCE. Statistical analysis was performed using Wilcoxon signed rank test and linear mixed models.

RESULTS

PCE assessment based on Q-PSI_max was associated with a significantly smaller coefficient of variation compared with Q-PSI_mean , with median values of 0.17 versus 0.21 (p = .002). Analysis of dynamic PCE revealed an optimal timing interval for image acquisition 4 min after contrast media application. No significant differences in PCE were observed by comparing age groups, female versus male participants and maxillary versus mandibular teeth (p > .05). Differences between tooth types were small (median Q-PSI_max values of 2.52/2.32/2.30/2.20 for molars/premolars/canines/incisors) but significant (p < .05), except for the comparison of canines versus premolars (p = .80).

CONCLUSIONS

PCE in dMRI was a stable intra-individual marker with only minor differences between different tooth types, thus forming an important basis for intra-individual controls when assessing teeth with suspected endodontic pathosis. Furthermore, it was demonstrated that PCE is independent of age, gender and jaw type. These findings indicate that dMRI-based PCE analysis could be a valuable diagnostic tool for the identification of various pulp diseases in future patient studies.

Differential Diagnosis of Cysts and Granulomas Supported by Texture Analysis of Intraoral Radiographs

The aim of this study was to evaluate whether textural analysis could differentiate between the two common types of lytic lesions imaged with use of radiography. Sixty-two patients were enrolled in the study with intraoral radiograph images and a histological reference study. Full textural analysis was performed using MaZda software. For over 10,000 features, logistic regression models were applied. Fragments containing lesion edges were characterized by significant correlation of structural information. Although the input images were stored using lossy compression and their scale was not preserved, the obtained results confirmed the possibility of distinguishing between cysts and granulomas with use of textural analysis of intraoral radiographs. It was shown that the important information distinguishing the aforementioned types of lesions is located at the edges and not within the lesion.

[Interpretation of periapical healing in radiological images. A review]

Interpretation of the state of healing of chronic apical periodontitis or apical curettage with apicoectomy in radiological images is based on the analysis of changes in the appearance of the periapical area and in the bone structure adjacent to the site of inflammation or surgical intervention, which are projected onto normal bone structures. However, distortion of structures or the superposition of anatomical images should be considered when interpreting radiographs. We compared conventional studies of evaluation of the periapical area following treatment, together with 2D images, with the periapical index and the criteria of evaluation in both successful and unsuccessful cases of endodontic surgical treatment. Some studies have reported that the radiographic appearance of the tooth crown and root may facilitate interpretation of the periapical area. In addition, cone-beam computed tomography can show the relationship between injured and repairing tissue using buccal and lingual tables to measure the periphery in transverse reconstruction. Indeed, complex biological events and mechanisms can occur during the healing process of periapical and root tissues. Knowledge of the diversity of tissues is essential to identify the dynamics of the signs of regeneration or the presence of healing due to repair. Hence, the aim of this article was to identify the criteria used to interpret periapical healing in two-dimensional or three-dimensional images and their relationship with diagnosis and treatment according to the literature currently available.

Ultrasound Imaging versus Radiographs in Differentiating Periapical Lesions: A Systematic Review

BACKGROUND

Ultrasonography is a non-invasive method of diagnosing periapical lesions while radiologic methods are more common. Periapical lesions due to endodontic infection are one of the most common causes of periapical radiolucency that need to be distinguished to help determine the course of treatment. This review aimed to examine the accuracy of ultrasound and compare it to radiographs in distinguishing these lesions in vivo.

METHODS

This review process followed the PRISMA guidelines. A literature search of databases (PubMed, Scopus, Embase, and Web of Science) was conducted without any restrictions on time. Articles available in English were included. The selection was done according to the inclusion and exclusion criteria. The QUADAS-2 tool was used to assess the quality of the studies.

RESULTS

The search provided a total of 87 articles, out of which, five were selected for the final review. In all the studies, ultrasound had higher accuracy in distinguishing periapical lesions. All the studies indicated a risk of bias, especially in patient selection.

CONCLUSION

Within limitations, the study indicates that ultrasound is a better diagnostic tool to distinguish periapical lesions compared to radiographs but further studies with well-designed, rigorous protocols and low risk of bias are needed to provide stronger evidence.

An Update of the Possible Applications of Magnetic Resonance Imaging (MRI) in Dentistry: A Literature Review

This narrative review aims to evaluate the current evidence for the application of magnetic resonance imaging (MRI), a radiation-free diagnostic exam, in some fields of dentistry.

BACKGROUND

Radiographic imaging plays a significant role in current first and second level dental diagnostics and treatment planning. However, the main disadvantage is the high exposure to ionizing radiation for patients.

METHODS

A search for articles on dental MRI was performed using the PubMed electronic database, and 37 studies were included. Only some articles about endodontics, conservative dentistry, implantology, and oral and craniofacial surgery that best represented the aim of this study were selected.

RESULTS

All the included articles showed that MRI can obtain well-defined images, which can be applied in operative dentistry.

CONCLUSIONS

This review highlights the potential of MRI for diagnosis in dental clinical practice, without the risk of biological damage from continuous ionizing radiation exposure.

Effect of a formalin-based fixation method on bone mineral content in human ex-vivo specimens

OBJECTIVE

Histopathology of formalin-fixated human ex-vivo specimens may be used as reference standard for evaluation of diagnostic index tests like CBCT or MRI. The aim was to estimate changes in bone mineral content (BMC) over time in human ex-vivo bone specimens fixated in a formalin-based solution for 24 h followed by storage in an alcohol-based medium for six months, assessed by dual-energy X-ray absorptiometry (DXA).

METHODOLOGY

Bone specimens (n = 19) from human ex-vivo mandibles donated for science were included. BMC was measured by DXA before fixation (D₀), after 24 h of immersion fixation in a formalin-based solution (D₁), and hereafter every 30 days (M₁-M₆) during storage in a 30% ethanol-based storage medium for 6 months. Changes in BMC from D₀ to D₁ and from D₀ to M₆ were calculated and mean change in BMC estimated.

RESULTS

Mean change in BMC from D₀ to D₁ was -0.73% (95% CI -1.75%; 0.29%), and from D₀ to M₆ -1.19% (95% CI -2.14%; -0.23%).

CONCLUSIONS

No changes in BMC of ex-vivo human bone specimens were found after 24 h formalin-based immersion fixation. After six months storage in an ethanol-based medium, BMC mean loss of 1% was detected. In this range, changes in BMC are not clinically relevant.

Suitability of Magnetic Resonance Imaging for Guided Endodontics: Proof of Principle

INTRODUCTION

This proof-of-principle study aimed to demonstrate that magnetic resonance imaging (MRI) is sufficiently accurate for the detection of root canals using guided endodontics.

METHODS

One hundred extracted human teeth (anterior and premolar) were mounted onto 5 mandibular and 5 maxillary models, fitted with splints designed to accommodate a thin layer of aqueous gel for indirect imaging, and scanned by MRI. After MRI and intraoral scans were aligned using planning software, access cavities were planned virtually, and templates were manufactured with computer-aided design/computer-aided manufacturing, the access cavities were prepared. Cone-beam computed tomographic scans were performed and matched with the virtual preoperative planning data to determine the accuracy of access cavity preparation in terms of deviation between planned and prepared cavities in the mesiodistal and buccolingual dimensions and angle. Descriptive statistical analysis was performed, and the mean values were compared using the t test.

RESULTS

Ninety-one of 100 root canals were successfully scouted after MRI-guided access cavity preparation. The mean angle deviation was 1.82°. The mean deviation ranged from 0.21-0.31 mm at the base of the bur and from 0.28-0.44 mm at the tip of the bur. Preparation in the buccolingual dimension was significantly more precise in mandibular compared with maxillary teeth, and accuracy in the mesiodistal dimension was more precise in anterior teeth compared with premolars.

CONCLUSIONS

This in vitro study demonstrated the suitability of MRI for guided endodontic access cavity preparation.

MRI for the display of autologous onlay bone grafts during early healing-an experimental study

OBJECTIVES

Autologous bone grafts are the gold standard to augment deficient alveolar bone. Dimensional graft alterations during healing are not known as they are not accessible to radiography. Therefore, MRI was used to display autologous onlay bone grafts in vivo during early healing.

METHODS AND MATERIALS

Ten patients with alveolar bone atrophy and autologous onlay grafts were included. MRI was performed with a clinical MR system and an intraoral coil preoperatively (t0), 1 week (t1), 6 weeks (t2) and 12 weeks (t3) postoperatively, respectively. The graft volumes were assessed in MRI by manual segmentation by three examiners. Graft volumes for each time point were calculated and dimensional alteration was documented. Cortical and cancellous proportions of bone grafts were assessed. The intraobserver and interobserver variability were calculated. Statistical analysis was performed using a mixed linear regression model.

RESULTS

Autologous onlay bone grafts with cortical and cancellous properties were displayed in vivo in eight patients over 12 weeks. The fixation screws were visible as signal voids with a thin hyperintense fringe. The calculated volumes were between 0.12-0.74 cm³ (t1), 0.15-0.73 cm³ (t2), and 0.17-0.64 cm³ (t3). Median changes of bone graft volumes of -15% were observed. There was no significant difference between the examiners (p = 0.3).

CONCLUSIONS

MRI is eligible for the display and longitudinal observation of autologous onlay bone grafts. Image artifacts caused measurements deviations in some cases and minimized the precise assessment of graft volume. To the knowledge of the authors, this is the first study that used MRI for the longitudinal observation of autologous onlay bone grafts.

Ultrasound imaging for the differential diagnosis of periapical lesions of endodontic origin in comparison with histopathology - a systematic review and meta-analysis

BACKGROUND

Differentiating periapical lesions is important for treatment planning and subsequent treatment outcome.

OBJECTIVE

To assess the diagnostic accuracy of ultrasound imaging for the differentiation of periapical lesions in comparison with histopathology.

METHODS

PubMed, Scopus, Embase, Web of Science and ProQuest databases were searched for clinical studies published until June 2020 that evaluated the use of ultrasound (US) imaging for differential diagnosis of periapical lesions and used histopathology as the reference standard. Animal studies, laboratory-based studies, reviews and clinical studies not using a reference standard were excluded. Risk of bias (RoB) assessment was performed using a modified Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. The random effects model was used for quantitative analysis of the data, and the Deeks test was used for calculating publication bias. Quality of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Twelve articles were included in the systematic review, out of which ten articles were quantitatively assessed. All the articles had a high RoB and concerns regarding applicability in the patient selection domain. For the index test domain, seven articles had low and the remaining five had unclear RoB and concerns regarding applicability. In the reference standard domain, low RoB and concerns regarding applicability were observed for all the articles. The RoB was low in flow and timing domains in all the articles except for one, where it was high. Summary estimates of sensitivity and specificity of US to diagnose periapical granulomas were 0.94 and 0.98, whereas for periapical cysts it was 0.98 and 0.99, respectively. Area under the curve for diagnosis of both periapical granulomas and periapical cysts was 0.99. All the included articles had inherent publication bias. Quality of evidence using GRADE, for sensitivity, was moderate for periapical granulomas and high for periapical cysts, whereas for specificity, it was high for periapical granulomas and low for periapical cysts.

DISCUSSION

The available evidence is considered to be of low quality due to the observational nature of the studies and inherent publication bias.

CONCLUSION

Although the sensitivity and specificity for differentiating periapical cysts and periapical granulomas using US were high, taking the quality of evidence into consideration, it can serve as an additional tool in differential diagnosis of periapical lesions.

German Dentists' Preferences for the Treatment of Apical Periodontitis: A Cross-Sectional Survey

Currently, there is no standard treatment protocol for apical periodontitis (AP). Thus, restorable teeth might get extracted and replaced prosthetically. This study evaluated German dentists’ preferred AP treatment decisions and the influencing factors for selecting tooth retention by initial/repeated surgical/non-surgical root-canal treatment (RCT) or extraction with/without prosthetic replacement. Through an online-survey, participants (n = 260) rated different treatment options for four case scenarios with AP in anterior/posterior teeth without/with previous RCT. Statistical analysis included the Friedman test for intra-case comparisons and Chi-squared test for factor-associations (p ≤ 0.05). Tooth retention using initial/repeated RCT was ranked first in all scenarios and rated as (very) appropriate by most participants, while implant-supported crowns (ISC) and apicoectomy had the second ratings. ISC were preferred more on posterior teeth or previous root-canal-treated teeth. Rating levels of treatment options displayed significant differences for all case scenarios. Posterior tooth retention by RCT demonstrated a significant association with work experience. Tooth retention with previous RCT displayed a significant correlation with dentists’ privately insured patients. Most dentists preferred tooth preserving with initial/repeated RCT, while others selected non-evidence-based choices. This reflects a lack of consensus of AP treatment decisions in Germany. Fixed treatment guidelines and further evaluation of treatment–decision-correlated factors are recommended for correct treatment planning.

Differentiation of periapical granuloma from radicular cyst using cone beam computed tomography images texture analysis

Objective

This study aimed to investigate the use of texture analysis for characterization of radicular cysts and periapical granulomas and to assess its efficacy to differentiate between both lesions with histological diagnosis.

Methods

Cone beam computed tomography (CBCT) images were obtained from 19 patients with 25 periapical lesions (14 radicular cysts and 11 periapical granulomas) confirmed by biopsy. Regions of interest were created in the lesions from which 11 texture parameters were calculated. Spearman's correlation analysis was performed and adjusted with Benjamini-Hochberg false discovery rate procedure (FDR <0.005).

Results

The texture parameters used to differentiate the lesions were assessed by using a receiver operating characteristic analysis. Five texture parameters were predictive of lesion differentiation for eight positions: angular second moment; sum of squares; sum of average; contrast; correlation.

Conclusion

Texture analysis of CBCT scans distinguishes radicular cysts from periapical granulomas and can be a promising diagnostic tool for periapical lesions.

Clinical significance

Texture analysis can be used in diagnostic and treatment monitoring to provide supplementary information.

Cone beam computed tomography - extending its arm to explore new possibilities

Purpose

To determine whether the greyscale value depicted in cone beam computed tomography (CBCT) differentiates different benign osseous lesions of jaws and to measure the greyscale value of various osseous lesions of jaws and to find the correlation (if any) of these greyscale values to that of histopathological diagnosis.

Material and methods

This study was conducted in the Department of Oral Medicine and Radiology of the Dental Institute after obtaining approval from the Ethical Committee. CBCT scans of osseous lesions of jaws confirmed with histopathological reports depicting cystic or tumour-like lesions were included in the study. Greyscale values depicted in CBCT scans of osseous lesions were measured. The greyscale values were grouped as per the histopathological diagnosis, and these ranges were then tabulated and statistically evaluated.

Results

The mean value with standard deviation of greyscale values for cystic lesions was 1208.375 ± 93 and for that of the tumour group was 1603 ± 425.5.

Conclusions

The greyscale value is a useful tool in differentiating between different groups of osseous lesions of jaws.

Evaluation of magnetic resonance imaging artifacts caused by fixed orthodontic CAD/CAM retainers-an in vitro study

Objectives

Magnetic resonance imaging (MRI) image quality can be severely impaired by artifacts caused by fixed orthodontic retainers. In clinical practice, there is a trend towards using computer-aided design/computer-aided manufacturing (CAD/CAM) retainers. This study aimed to quantify MRI artifacts produced by these novel CAD/CAM retainers.

Material and methods

Three CAD/CAM retainers and a stainless-steel retainer (“Twistflex”; clinical reference standard) were scanned in vitro at 3-T MRI using a high-resolution 3D sequence. The artifact diameters and three-dimensional artifact volumes (AV) were determined for all mandibular (AV_mand) and maxillary (AV_max) retainers. Moreover, the corresponding ratio of artifact volume to retainer volume (AV/RV_mand, AV/RV_max) was calculated.

Results

Twistflex caused large artifact volumes (AV_mand: 13530 mm³; AV_max: 15642 mm³; AV/RV_mand: 2602; AV/RV_max: 2235). By contrast, artifact volumes for CAD/CAM retainers were substantially smaller: whereas artifact volumes for cobalt–chromium retainers were moderate (381 mm³; 394 mm³; 39; 31), grade-5 titanium (110 mm³; 126 mm³; 12; 12) and nickel–titanium (54 mm³; 78 mm³; 12; 14) both produced very small artifact volumes.

Conclusion

All CAD/CAM retainers caused substantially smaller volumes of MRI artifacts compared to Twistflex. Grade-5 titanium and nickel–titanium CAD/CAM retainers showed the smallest artifact volumes.

Clinical relevance

CAD/CAM retainers made from titanium or nickel–titanium may not relevantly impair image quality in head/neck and dental MRI. Artifacts caused by cobalt–chromium CAD/CAM retainers may mask nearby dental/periodontal structures. In contrast, the large artifacts caused by Twistflex are likely to severely impair diagnosis of oral and adjacent pathologies.

Endodontic Periapical Lesion: An Overview on the Etiology, Diagnosis and Current Treatment Modalities

Nonsurgical and surgical endodontic treatments have a high success rate in the treatment and prevention of apical periodontitis when carried out according to standard and accepted clinical principles. Nevertheless, endodontic periapical lesions remain in some cases, and further treatment should be considered when apical periodontitis persists. Although several treatment modalities have been proposed for endodontically treated teeth with persistent apical periodontitis, there is a need for less invasive methods with more predictable outcomes. The advantages and shortcomings of existing approaches for the diagnosis and treatment of endodontic periradicular lesions are discussed in this review.

Investigation of the effectiveness of CBCT and gray scale values in the differential diagnosis of apical cysts and granulomas

PURPOSE

The aim of this study was to investigate the effectiveness of cone-beam CT (CBCT) findings and gray scale values (GSV) in the differential diagnosis of apical cysts and granulomas.

METHODS

Two independent researchers retrospectively analyzed the CBCT images of 21 teeth and histopathologically diagnosed them as having radicular cysts or apical granulomas. In the CBCT images, apical lesions were evaluated and categorized according to 7 criteria. These criteria were determined as relationship of lesions with dental roots, periphery of the lesion, shape, darker focus in the center, root resorption, displacement in related teeth, and cortical bone perforation. In addition, the minimum and maximum gray scale values of the lesions were measured and compared.

RESULTS

There was a statistically significant relationship between histopathological (HP) diagnosis and well-defined cortical border and lesion shape (p = 0.003, p = 0.014, respectively). According to the HP diagnosis, no statistically significant difference was found among other variables (p > 0.05) CONCLUSION: The presence of a well-defined cortical border or partial cortical border is a distinctive criterion for cysts. Additionally, the shape of the lesion was found to be a significant criterion for the separation of the two lesions. The shape of cystic lesions was circular and apical granulomas had a more curved shape. There was no relationship between the histopathological diagnosis of lesions and CBCT gray scale values.

Utilização da imagem por ressonância magnética na odontologia: revisão de literatura

A Imagem por Ressonância Magnética (IRM) tem sido considerada a modalidade de escolha para o diagnóstico de processos patológicos que acometem a articulação temporomandibular, tecidos moles e outros processos inflamatórios. Devido a sua característica não invasiva e livre de radiação ionizante, novas aplicações para a técnica têm sido propostas e estudadas nas mais diversas áreas da Odontologia, como Endodontia, Dentística, Periodontia e Cirurgia Oral. O objetivo neste trabalho é apresentar uma revisão de literatura acerca da utilização da IRM na Odontologia, destacando as vantagens e limitações da técnica.