Imaging of Benign Odontogenic Lesions

Factors and management techniques in odontogenic keratocysts: a systematic review

OBJECTIVES

Odontogenic keratocysts exhibit frequent recurrence, distinctive histopathological traits, a tendency towards aggressive clinical behavior, and a potential linkage to the nevoid basal cell carcinoma syndrome. The aim of this systematic review is to compile insights concerning the control of this condition and assess the effectiveness of various treatment approaches in reducing the likelihood of recurrence.

MATERIALS AND METHODS

The following systematic review adhered to the PRISMA guidelines. The systematic revision was registered on PROSPERO and  structured around the questions related to the population, intervention, control, outcome and study design (PICOS).

RESULTS

After conducting a search on the PubMed database, we initially identified 944 records. After using end-note software to remove duplicate entries, results totally with 462 distinct records. A thorough review of the titles and abstracts of these articles led to the selection of 50 papers for in-depth examination. Ultimately, following the application of our eligibility criteria, we incorporated 11 articles into our primary outcome analysis.

CONCLUSION

Among the studies examined, the most common location for these lesions was found to be in the area of the mandibular ramus and the posterior region of the mandible. In cases where the exact location wasn't specified, the mandible emerged as the predominant site. When we considered the characteristics of these lesions in studies that mentioned locularity, most were described as unilocular in two studies, while in two other studies, the prevalence of multilocular lesions was observed. Risk factors associated with keratocyst recurrence include younger patient age, the presence of multilocular lesions, larger lesion size, and a longer anteroposterior dimension. Certain treatment methods have demonstrated a lack of relapses. These include the use of 5-fluorouracil, marsupialization, enucleation with peripheral ostectomy or resection, enucleation and curettage, as well as resection without creating continuity defects. However, it is important to note that further research is essential. Prospective studies and randomized trials are needed to collect more comprehensive evidence regarding the effectiveness of various treatment approaches and follow-up protocols for managing odontogenic keratocysts.

CLINICAL RELEVANCE

Odontogenic keratocysts still enter into differential diagnoses with other lesions that affect the jaw bones such as ameloblastama and other tumor forms, furthermore it is not free from recurrence, therefore the therapeutic approach to the lesion aimed at its elimination can influence both the possible recurrence and complications, knowledge of the surgical methods that offer the most predictable and clinically relevant result for the management of follow-up and recurrences.

Deep learning for detection and 3D segmentation of maxillofacial bone lesions in cone beam CT

OBJECTIVES

To develop an automated deep-learning algorithm for detection and 3D segmentation of incidental bone lesions in maxillofacial CBCT scans.

METHODS

The dataset included 82 cone beam CT (CBCT) scans, 41 with histologically confirmed benign bone lesions (BL) and 41 control scans (without lesions), obtained using three CBCT devices with diverse imaging protocols. Lesions were marked in all axial slices by experienced maxillofacial radiologists. All cases were divided into sub-datasets: training (20,214 axial images), validation (4530 axial images), and testing (6795 axial images). A Mask-RCNN algorithm segmented the bone lesions in each axial slice. Analysis of sequential slices was used for improving the Mask-RCNN performance and classifying each CBCT scan as containing bone lesions or not. Finally, the algorithm generated 3D segmentations of the lesions and calculated their volumes.

RESULTS

The algorithm correctly classified all CBCT cases as containing bone lesions or not, with an accuracy of 100%. The algorithm detected the bone lesion in axial images with high sensitivity (95.9%) and high precision (98.9%) with an average dice coefficient of 83.5%.

CONCLUSIONS

The developed algorithm detected and segmented bone lesions in CBCT scans with high accuracy and may serve as a computerized tool for detecting incidental bone lesions in CBCT imaging.

CLINICAL RELEVANCE

Our novel deep-learning algorithm detects incidental hypodense bone lesions in cone beam CT scans, using various imaging devices and protocols. This algorithm may reduce patients' morbidity and mortality, particularly since currently, cone beam CT interpretation is not always preformed.

KEY POINTS

• A deep learning algorithm was developed for automatic detection and 3D segmentation of various maxillofacial bone lesions in CBCT scans, irrespective of the CBCT device or the scanning protocol. • The developed algorithm can detect incidental jaw lesions with high accuracy, generates a 3D segmentation of the lesion, and calculates the lesion volume.

A Narrative Review on Current Diagnostic Imaging Tools for Dentomaxillofacial Abnormalities in Children

The current review narrates the findings and discusses the available diagnostic tools for detecting structural abnormalities. The review discusses several diagnostic tools, such as magnetic resonance imaging, cone beam computed tomography, multi detector row CT and positron emission tomography. The vital findings and comparative analysis of different diagnostic tools are presented in this review. The present review also discusses the advent of newer technologies, such as the HyperionX9 scanner with less field of view and 18F-FDG PET/CT (positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-D-glucose, integrated with computed tomography), which can give more efficient imaging of dentomaxillofacial structures. The discussion of effective comparative points enables this review to reveal the available diagnostic tools that can be used in the detection of dentomaxillofacial abnormalities in the pediatric population. The advantages and disadvantages of each tool are discussed, and the findings of past publications are also presented. Overall, this review discusses the technical details and provides a comparative analysis of updated diagnostic techniques for dentomaxillofacial diagnosis.

Computer tomographic differential diagnosis of ameloblastoma and odontogenic keratocyst: classification using a convolutional neural network

OBJECTIVE

To analyse the automatic classification performance of a convolutional neural network (CNN), Google Inception v3, using tomographic images of odontogenic keratocysts (OKCs) and ameloblastomas (AMs).

METHODS

For construction of the database, we selected axial multidetector CT images from patients with confirmed AM (n = 22) and OKC (n = 18) based on a conclusive histopathological report. The images (n = 350) were segmented manually and data augmentation algorithms were applied, totalling 2500 images. The k-fold × five cross-validation method (k = 2) was used to estimate the accuracy of the CNN model.

RESULTS

The accuracy and standard deviation (%) of cross-validation for the five iterations performed were 90.16 ± 0.95, 91.37 ± 0.57, 91.62 ± 0.19, 92.48 ± 0.16 and 91.21 ± 0.87, respectively. A higher error rate was observed for the classification of AM images.

CONCLUSION

This study demonstrated a high classification accuracy of Google Inception v3 for tomographic images of OKCs and AMs. However, AMs images presented the higher error rate.

Patterns of Cone-Beam Computed Tomography (CBCT) Utilization by Various Dental Specialties: A 4-Year Retrospective Analysis from a Dental and Maxillofacial Specialty Center

The study aimed to analyze the uses of cone-beam computed tomography (CBCT) in the diagnosis and treatment in various dental specialties. This 4-year cross-sectional study analyzed the records of 1409 individuals who underwent a CBCT at the Oral and Maxillofacial Center at Sheba Medical Center, Israel. The average age of the patients was 27.9 ± 11.5 (range: 9-86 years). Patients were referred for CBCT by the following departments: Oral and Maxillofacial Surgery (1063; 75.5%), Endodontics (182; 12.9%), Periodontology (122; 8.6%) and Orthodontics (42; 3.0%). Most CBCT radiographs evaluated the maxilla (774; 55.0%), followed by the mandible (481; 34.1%) and both (154; 10.9%). The target anatomical structures included: bone (694; 49.3%), teeth (307; 21.7%), and both jaws (408; 29.0%). The main indications for CBCT use were: assessment of anatomical structures and implant sites (787; 55.9%), determine root canals morphology (182; 12.9%), visualization of impacted teeth, tooth alignment, and localization (177; 12.6%), suspected cysts or tumors (148; 10.5%), evaluation of Temporomandibular joint disorders (106; 7.5%) and other reasons (9; 0.6%). In 279 (19.8%) of cases, the diagnosis changed following CBCT, mainly in Orthodontics tooth analysis (28 (66.7%); p < 0.001). Practitioners and health authorities should be aware of this baseline information regarding CBCT use in the diagnosis and assessment of various oral and maxillofacial pathologies, anomalies and tooth position relative to anatomic structures. Continuing research and publications of CBCT utilization and guidelines are recommended.

[Three-dimentional radiographic features of 67 maxillary radicular cysts]

OBJECTIVE

To analyze the three-dimensional radiographic characteristics of maxillary radi-cular cysts using cone-beam computed tomography (CBCT) and spiral CT.

METHODS

Clinical records, histopathological reports, and CBCT or non-enhanced spiral CT images of 67 consecutive patients with maxillary radicular cysts were retrospectively acquired, and radiographic features, including size, shape, expansion, internal structure and relationship with the surrounding tissues, were analyzed. The lesions were divided into three types according to the involved tooth number, as follows: type Ⅰ (single tooth), the epicenter of the cyst was located at the apex of a nonvital tooth, without involvement of the neighbo-ring tooth; type Ⅱ (adjacent tooth involvement), the cyst was located at the apex of a nonvital tooth with involvement of the mesial and/or distal tooth root; and type Ⅲ (multi-teeth), the cyst involved the apexes of ≥4 teeth. Besides, these cysts were classified as another three types on sagittal views, as follows: centripetal, the root apex was oriented centripetally to the center of the cyst; palatal, the cyst was located mainly at the palatal side of the apex; and labial/buccal, the cyst was located mainly at the labial/buccal side of the apex.

RESULTS

Totally, 67 patients with maxillary radicular cysts were acquired, including 38 males and 29 females, and their ages ranged from 13 to 77 years. Among them, 46 lesions (68.7%) were located in the anterior maxilla and 65 (97.0%) were round or oval. Labial/buccal cortex expansion was present in 43 cases (64.2%) and palatal cortex expansion in 37 cases (55.2%). The nasal floor was invaded in 27 cases (40.3%), the maxillary sinus was invaginated in 26 cases (38.8%), and root resorption was present in 9 cases (13.4%). The average diameter of lesions was (20.89±8.11) mm mesio-distally and (16.70±5.88) mm bucco-palatally. In spite of the 4 residual cysts, the remaining 63 lesions included 14 type Ⅰ, 26 type Ⅱ and 23 type Ⅲ cysts according to the involved tooth number. Besides, the 63 lesions included 46 centripetal, 15 palatal and 2 buccal cysts on sagittal views.

CONCLUSION

The maxillary radicular cysts were frequently well-circumscribed round or oval radiolucency, with significantly different sizes. According to the involved tooth number, it can be divided into single tooth, adjacent tooth involvement and multi-teeth types. On sagittal views, the root-cyst relationship was centripetal in most cases, while a minority of cysts expanded palatally or buccally.

Radicular cysts and Chin implants; An unexpected complication prompting explantation - Case report

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Radicular cysts are benign, odontogenic, and inflammatory in nature that commonly arise in the maxilla.

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No link has been previously found between silicone chin implants and radicular cysts or fistulating radicular cysts.

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We suggest dental panoramic X-ray screening for patients with poor oral hygiene or dental trauma to detect radicular cysts before the operation.

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The decision to proceed with chin implant in a patient known for treated radicular cyst may be unsafe, as the recurrence rate is unknown.

Introduction

Implant-based genioplasty is a simple and safe but not complication-free cosmetic procedure. Patients are commonly briefed about anticipated complications and their management pre-operatively, but few unexpected complications may arise; and this case report is an example. This paper is the first to report a radicular cyst fistulating through chin implant pocket to the skin. Moreover, we present our prevention strategy and recommendations.

Presentation of case

A 39-year-old-lady underwent a silicone implant-based genioplasty that was uneventful. Later, she developed a reddish nodule on the chin necessitating fistulectomy followed by a recurrence leading to explantation. It was not until the second recurrence that a fistulating radicular cyst was discovered and was treated with the help of a dentist.

Discussion

Radicular cysts are benign, inflammatory cysts that arise in a background of dental trauma or caries. No link has been discovered yet between silicone implants and radicular cysts or fistulating cysts. Moreover, we propose that poor oral hygiene could be implicated in the development of these cysts. Dental panoramic X-ray has been used to diagnose radicular cysts, but its efficacy as a screening tool needs to be studied. Finally, the recurrence rate of radicular cysts is unknown.

Conclusion

In a patient with chin implant, radicular cysts could lead to a disastrous outcome. Through history and physical examination, a plastic surgeon should identify patients with poor oral hygiene and dental trauma prior to implant-based genioplasty to arrange for a dental panoramic X-ray. Patients known to have radicular cysts should not undergo an implant-based genioplasty.

Cross-Sectional Imaging of Third Molar-Related Abnormalities

Third molars may be associated with a wide range of pathologic conditions, including mechanical, inflammatory, infectious, cystic, neoplastic, and iatrogenic. Diagnosis of third molar-related conditions can be challenging for radiologists who lack experience in dental imaging. Appropriate imaging evaluation can help practicing radiologists arrive at correct diagnoses, thus improving patient care. This review discusses the imaging findings of various conditions related to third molars, highlighting relevant anatomy and cross-sectional imaging techniques. In addition, key imaging findings of complications of third molar extraction are presented.

Is peripheral cortication of intraosseous lesions accurately displayed on panoramic radiography?

OBJECTIVE

The aim of this study was to calculate the sensitivity, specificity, and positive and negative predictive values (PPV and NPV) for the detection of the presence and continuity of peripheral cortication (PC) around benign intraosseous lesions on panoramic radiography (PR), with cone beam computed tomography (CBCT) as the reference standard.

STUDY DESIGN

The sample consisted of the mesial, distal, superior, and inferior borders of 40 bony lesions (n = 160) depicted on both PR and CBCT. Ten observers assessed the PRs. CBCT images were assessed by 2 radiologists. For each lesion, observers classified the 4 borders with regard to the presence of PC, and if present, its continuity. Sensitivity, specificity, PPV, and NPV were calculated for the presence and continuity of PC. Intra- and interobserver agreements were calculated.

RESULTS

PR had sensitivity, specificity, PPV, and NPV for PC detection of 0.844, 0.435, 0.435, and 0.844, respectively. With regard to PC continuity, those values were 0.750, 0.810, 0.577, and 0.904. Observer agreement was slight to fair.

CONCLUSIONS

The high sensitivity and low specificity for the presence of PC indicate a large false-positive rate. The high NPVs suggest greater validity for negative decisions. The findings corroborate the influence of the eggshell effect. Observer agreement rates indicate that interpretation of PC is substantially subjective.

Odontogenic keratocyst: An incidental finding during an orthodontic examination

For all orthodontic patients, a detailed clinical examination is essential to obtain the correct diagnosis before the formulation of an orthodontic treatment plan. Additional information may be required from radiographs in order to supplement this clinical examination. While orthodontists principally prescribe dental panoramic tomographs for orthodontic patients to confirm the presence, position and morphology of unerupted teeth, the absence or presence of disease within the supporting structures may be overlooked. This case report presents one such instance where the pre-orthodontic radiographic examination of a young male patient revealed the presence of an asymptomatic odontogenic keratocyst in the right posterior body of the mandible.

This case report discusses how this incidental finding was diagnosed, managed and how its surgical treatment subsequently affected the orthodontic management of the patient. Furthermore, this case highlights the importance of undertaking a thorough and systematic approach when analysing any prescribed radiographs, in order to reduce the risk of overlooking any evidence of underlying disease.

Differential Diagnosis of Periapical Radiopacities and Radiolucencies

Periapical pathoses represent changes noted at the apices of teeth within the alveolar process that are suspected on examination, visualized via imaging, and confirmed via histopathology. They can be bone forming or destructive. There are pathologic entities that show both types of changes at the apical regions. These lesions must be identified if they are odontogenic in origin because treatment modalities differ. This article discusses identification of radiopaque and radiolucent lesions noted on radiographs. The common opacities and lucencies are described. When required, advanced imaging is used to depict changes within the bone near the periapical regions of mandibular and maxillary teeth.

Nonsyndromic Examples of Odontogenic Keratocysts: Presentation of Interesting Cases with a Literature Review

The odontogenic keratocyst (OKC) may occur at any age. However, it mostly occurs during the second and third decades of life. Compared to other odontogenic cysts, this type occurs with a frequency of 5-15%. It is more common in the mandible region and in the male sex. Histologically, odontogenic keratocysts are characterized by the presence of an external connective tissue capsule, with keratinizing lining of the epithelium consisting of 5-8 cell layers with marked palisadisation of polarized basal cells and a corrugated parakeratin layer. The objective of this study is to present cases of odontogenic keratocysts, with reference to the latest classification and dilemmas in therapeutic doctrine. This project was realized in the form of descriptive studies, specifically in a series of cases. A collection of four individual cases was found at the Department of Oral Surgery. Due to the proper approach towards diagnosis, adequate and detailed histopathological analysis, and suitable therapeutic procedures, all cases of odontogenic keratocysts were successfully treated without complications. Enucleation of OKC, with a regular follow-up, proved to be the effective therapeutic choice for the patients described in this paper. Only in the case of recurrence would we consider other therapeutic options, primarily enucleation in combination with Carnoy's solution.

Three-dimensional radiographic features of ameloblastoma and cystic lesions in the maxilla

OBJECTIVES

To characterize the radiographic features of maxillary ameloblastoma (AM), odontogenic keratocyst (OKC) and dentigerous cyst (DC) comparatively by using spiral CT and cone beam CT (CBCT).

METHODS

Clinical records, histopathological reports, and nonenhanced spiral CT or CBCT images of 191 consecutive patients with primary maxillary AMs, OKCs, or DCs were retrospectively acquired, and radiographic features were analyzed.

RESULTS

The study included 118 males and 73 females (age: 5-84 years). 72.0% of AMs and 84.3% of OKCs originated from the posterior maxilla, while 69.6% of DCs occurred in the anterior maxilla. Among 25 AMs, 44.0% were of desmoplastic type, with honey-combed appearance. 84.0% of AMs were circular or oval in shape, 84.0% expanded buccally, and 36.0% invade the nasal floor. Among 89 OKCs of 88 patients, 61.8% were circular or oval, 58.4% expanded buccally, 49.4% were dentigerous, 41.6% nearly filled the maxillary sinus, and 13.5% invaded the nasal floor. 93.7% (74/79) of DCs enveloped a single tooth, and the tooth-cyst relationship was centripetal in 35, eccentric in 30, and circumferential in 9. Moreover, 98.2% (55/56) of the cysts enveloping a supernumerary tooth were DCs, while 80.9% (38/47) of the cysts enveloping the third molar were OKCs.

CONCLUSIONS

Maxillary AMs tend to grow with buccal expansion and invade the nasal floor, and DAs with honey-combed lobularity are common. Maxillary OKCs have variant shapes and tend to invaginate the maxillary sinus. The tooth-cyst relationship of dentigerous OKCs and DCs can be centripetal, eccentric, or circumferential.

Cone Beam Computed Tomography in Oral and Maxillofacial Surgery: An Evidence-Based Review

Cone Beam Computed Tomography (CBCT) is a valuable imaging technique in oral and maxillofacial surgery (OMS) that can help direct a surgeon’s approach to a variety of conditions. A 3-dimensional analysis of head and neck anatomy allows practitioners to plan appropriately, operate with confidence, and assess results post-operatively. CBCT imaging has clear indications and limitations. CBCT offers the clinician 3-dimensional and multi-planar views for a more accurate diagnosis and treatment without the financial burden and radiation exposure of conventional computed tomography (CT) scans. Furthermore, CBCT overcomes certain limitations of 2-dimensional imaging, such as distortion, magnification, and superimposition. However, CBCT lacks the detailed depiction of soft tissue conditions for evaluation of pathologic conditions, head and neck infections, and temporomandibular joint (TMJ) disc evaluation. This review evaluates the evidence-based research supporting the application of CBCT in the various fields of oral and maxillofacial surgery, including dentoalveolar surgery, dental implants, TMJ, orthognathic surgery, trauma, and pathology, and will assess the value of CBCT in pre-operative assessment, surgical planning, and post-operative analysis when applicable. Additionally, the significant limitations of CBCT and potential areas for future research will be discussed.

Odontogenic keratocyst: imaging features of a benign lesion with an aggressive behaviour

Abstract

The latest (4th) edition of the World Health Organization (WHO) Classification of Head and Neck Tumours, published in January 2017, has reclassified keratocystic odontogenic tumour as odontogenic keratocyst. Therefore, odontogenic keratocysts (OKCs) are now considered benign cysts of odontogenic origin that account for about 10% of all odontogenic cysts. OKCs arise from the dental lamina and are characterised by a cystic space containing desquamated keratin with a uniform lining of parakeratinised squamous epithelium. The reported age distribution of OKCs is considerably wide, with a peak of incidence in the third decade of life and a slight male predominance. OKCs originate in tooth-bearing regions and the mandible is more often affected than the maxilla. In the mandible, the most common location is the posterior sextant, the angle or the ramus. Conversely, the anterior sextant and the third molar region are the most common sites of origin in the maxilla. OKCs are characterised by an aggressive behaviour with a relatively high recurrence rate, particularly when OKCs are associated with syndromes. Multiple OKCs are typically associated with the nevoid basal cell carcinoma syndrome (NBCCS), an autosomal dominant multisystemic disease. Radiological imaging, mainly computed tomography (CT) and, in selected cases, magnetic resonance imaging (MRI), plays an important role in the diagnosis and management of OKCs. Therefore, the main purpose of this pictorial review is to present the imaging appearance of OKCs underlining the specific findings of different imaging modalities and to provide key radiologic features helping the differential diagnoses from other cystic and neoplastic lesions of odontogenic origin.

Key Points

• Panoramic radiography is helpful in the preliminary assessment of OKCs.

• CT is considered the tool of choice in the evaluation of OKCs.

• MRI with DWI or DKI can help differentiate OKCs from other odontogenic lesions.

• Ameloblastoma, dentigerous and radicular cysts should be considered in the differential diagnosis.

• The presence of multiple OKCs is one of the major criteria for the diagnosis of NBCCS.