Lesions of the jaws presenting as radiolucencies on cone-beam CT

Uncovering the Hidden: A Study on Incidental Findings on CBCT Scans Leading to External Referrals

OBJECTIVES

This project aims to determine the prevalence of cone-beam computed tomography (CBCT) findings requiring referral. Additionally, the goal is to establish a reference standard protocol for incidental findings, outlining indications for further investigation and management protocol.

METHODS

Patients records from the Advanced Imaging Centre at the School of Dentistry, University of Alberta, underwent systematic examination to identify CBCT incidental findings. Radiographic findings requiring referral were categorised into 8 anatomic zones. Analysis assessed prevalence and a management protocol was developed for significant findings. Inferential analyses were conducted to determine the frequency and prevalence of specific findings requiring further investigation.

RESULTS

A total of 1260 CBCT interpretive reports were analysed. The most prevalent radiographic findings outside the areas of interest were found in the cervical vertebrae (18%), followed by the sinuses (15%), temporomandibular joints (8%), jaw lesions (7%), airway (5%), teeth (5%), soft tissue calcifications (5%), and other (1%).

CONCLUSIONS

Findings most commonly requiring external referral included carotid atheroma (2.7%), cervical vertebrae osteoarthritis (0.97%), jaw lesions (0.86%), adenoid and/or tonsillar hypertrophy (0.86%), and paranasal sinus pathology (0.73%). Increased medicolegal awareness and practitioner knowledge contribute to the rising number of CBCT-identified radiographic findings outside the area of concern. The study addresses the debate on reporting all CBCT/radiographic findings by exploring their prevalence and providing protocols. These guidelines assist dentists in identification, decision-making, and referral processes.

Diagnosis of common intraosseous lesions of the dentomaxillofacial region by chemometry-assisted FT-IR spectroscopy in dental tissue samples

PURPOSES

This study aimed to determine the differential diagnosis of three intraosseous lesions (odontogenic keratocyst (OKC), central giant cell granuloma (CGCG), and dentigerous cyst (DC)) of the dentomaxillofacial region with very similar radiological and clinical features by using chemometrics assisted FT-IR (Fourier transform infrared) spectroscopy in tissue samples.

METHODS

Tissue samples (exposed to formaldehyde for a similar time) of 20-micron thickness belonging to 19 intraosseous lesions diagnosed histopathologically were obtained from the pathology laboratory. The samples were analyzed by FT-IR spectroscopic method using the 400-4000 cm-1 wavenumber range, and the obtained spectra of the samples were evaluated using the orthogonal partial least squares discriminant analysis (OPLS-DA) algorithm.

RESULTS

The intraosseous lesions with different histopathological diagnoses were accurately and precisely clustered with different FT-IR bands corresponding to the main molecular vibrations, especially the phosphodiester region, of the tissue components using the proposed model with 3 latent variables.

CONCLUSIONS

The model showed high sensitivity and specificity. The present study is the first to report the elucidation of clear spectral differences between similar lesions in the maxillofacial region. In the future, the FT-IR method may be used in the non-destructive classification of similar lesions in the maxillofacial region as an alternative to histopathological evaluation.

Odontogenic Keratocyst Presented as Multi-Locular Radiolucency in Mandibular Canine and Premolar Region: A Case Report

An odontogenic keratocyst (OKC) was first described by Philipsen in 1956. They are benign cysts of odontogenic origin that behave aggressively and have a high recurrence rate. The present case report describes an unusual presentation of OKC as a multi-locular lesion in the anterior mandible. A 14-year-old male patient was referred to the oral maxillofacial surgery clinic in Tabuk Specialist Dental Centre by his orthodontist to evaluate a radiolucent lesion that had been identified in his lower anterior teeth during an OPG examination. The patient was medically fit and had multiple previous dental restorations. An intraoral examination revealed a small bony expansion in the cystic lesion on the buccal side. The panoramic radiograph showed well-defined multi-locular radiolucencies in the lower left canine area, despite there being no tooth resorption; however, there was a slight divergence noted between the teeth. An excisional biopsy was performed, and the subsequent histopathological examination revealed a cystic lesion diagnosed as an odontogenic keratocyst. The six-month follow-up OPG showed that the site had completely healed without any lesions recurring. OKCs can present at any age, irrespective of gender. The differential diagnosis included a lateral periodontal cyst or a radicular cyst when the tooth was not vital. In this case, the six-month follow-up OPG following surgery revealed no recurrence, although a close follow-up is recommended because of the high recurrence rate.

Odontogenic keratocyst in the mandibular condyle base region: A case report

Odontogenic keratocysts (OKCs) often occur in the molars in the mandibular ramus; they often progress asymptomatically and are discovered only after widespread development. Some cases of OKC progress to the mandibular condyle; however, very few cases exist only in the condyle. To the best of our knowledge, in all of the previously reported cases, OKCs occurred in the mandibular ramus, which underwent resection. The present study reports the case of a 31-year-old man in whom an OKC (13x12x6 mm) occurred discretely in the base of the condyle, in which the condylar head was successfully preserved. The tumor was removed under general anesthesia using the approach of shaving the anterior surface of the mandible. The extraction cavity was managed using the packed open technique and with an obturator. Approximately 20 months post-operation, the patient remained recurrence-free. This report presents a rare case of an OKC in the mandibular condyle base region. Resection was performed under general anesthesia and the condylar process was successfully preserved.

Efficiency and Safety of Dental Implantation in the Area of Hyperdense Jaw Lesions: A Narrative Review

Background. Mineralized lesions of the jaws are often found incidentally on radiographs and computed tomography. Most of them are benign, and only a few rare cases are associated with malignant transformation. However, there is little clinical data on successful rehabilitation with implants in patients with mineralized lesions. This narrative review aimed to study the efficiency and safety of dental implantation in the area of hyperdense lesions. Materials and Methods. A PubMed, Google Scholar, and Science Direct database search was carried out with keywords and manually. Results. The literature exploration identified 323 articles; only 19 of them matched the search criteria and reported cases about dental implantation in the lesion area. It has been shown that in 84.2% of described cases, dental implantation was successful: in the osteoid osteoma, odontoma, cementoblastoma, idiopathic osteosclerosis, and condensing osteitis areas dental implantation was performed without any complications. The possibility of lesion recurrence and implant failure limited the use of dental implants in the area of osteoblastoma and cemento-osseous dysplasia. Although most cases of dental implantation in hyperdense jaw lesions were successful and were not accompanied by complications, further research is needed.

Efficacy of bone grafts in jaw cystic lesions: A systematic review

BACKGROUND

Bone grafts have been applied for many years in orthopedic surgery to assist with bone repair for defects or bone discontinuity caused by trauma and tumors as well as periodontal defects. Jaw cysts are another common benign disease of the maxillofacial region which may lead to pathological bone fracture, loss of teeth, and infection. However, whether bone grafts are beneficial for bone regeneration in jaw cystic lesions and when bone grafts should be used remains unclear.

AIM

To study the efficacy of bone grafts compared to spontaneous healing in the treatment of jaw cystic lesions.

METHODS

A literature search was performed in Medline, Cochrane Library and Embase to identify related articles published in English in the last ten years. The following key words and MeSH terms were used: “jaw cyst”, “cystic lesion”, “odontogenic cyst”, “periapical cyst”, “dentigerous cyst”, “follicular cyst”, “keratocyst”, “treatment”, “surgery”, “bone graft”, “enucleation”, “cystectomy”, and “bone regeneration”. Case reports, clinical trials, clinical studies, observational studies and randomized controlled trials were included. Study quality was evaluated.

RESULTS

Ten studies (n = 10) met the inclusion criteria. Five studies reported spontaneous bone healing after enucleation, three studies investigated the efficacy of various bone grafts, and two randomized comparative studies focused on the comparison between spontaneous healing and bone grafting. Over 90% of bone regeneration occurred within 6 mo after bone grafting. The bone regeneration rate after cystectomy showed great variation, ranging from 50% to 100% after 6 mo, but reaching over 90% after 12 mo.

CONCLUSION

While the long-term superiority of bone grafting compared with spontaneous healing after cystectomy is unclear, bone grafts accelerate the process of healing and significantly increase bone quality.

Efficacy of bone grafts in jaw cystic lesions: A systematic review

BACKGROUND

Bone grafts have been applied for many years in orthopedic surgery to assist with bone repair for defects or bone discontinuity caused by trauma and tumors as well as periodontal defects. Jaw cysts are another common benign disease of the maxillofacial region which may lead to pathological bone fracture, loss of teeth, and infection. However, whether bone grafts are beneficial for bone regeneration in jaw cystic lesions and when bone grafts should be used remains unclear.

AIM

To study the efficacy of bone grafts compared to spontaneous healing in the treatment of jaw cystic lesions.

METHODS

A literature search was performed in Medline, Cochrane Library and Embase to identify related articles published in English in the last ten years. The following key words and MeSH terms were used: “jaw cyst”, “cystic lesion”, “odontogenic cyst”, “periapical cyst”, “dentigerous cyst”, “follicular cyst”, “keratocyst”, “treatment”, “surgery”, “bone graft”, “enucleation”, “cystectomy”, and “bone regeneration”. Case reports, clinical trials, clinical studies, observational studies and randomized controlled trials were included. Study quality was evaluated.

RESULTS

Ten studies (n = 10) met the inclusion criteria. Five studies reported spontaneous bone healing after enucleation, three studies investigated the efficacy of various bone grafts, and two randomized comparative studies focused on the comparison between spontaneous healing and bone grafting. Over 90% of bone regeneration occurred within 6 mo after bone grafting. The bone regeneration rate after cystectomy showed great variation, ranging from 50% to 100% after 6 mo, but reaching over 90% after 12 mo.

CONCLUSION

While the long-term superiority of bone grafting compared with spontaneous healing after cystectomy is unclear, bone grafts accelerate the process of healing and significantly increase bone quality.

Radiolucent Lesions of the Jaws: An Attempted Demonstration of the Use of Co-Word Analysis to List Main Similar Pathologies

(1) Background: Many radiolucent jaw lesions exist, and they often show a radiographic resemblance, rendering diagnosis a challenging act. Closely related lesions should be frequently mentioned together in the academic literature, which might be helpful for junior practitioners in determining their differential diagnosis. The usefulness of bibliometric analysis in this respect has yet to be demonstrated. (2) Methods: This study evaluated academic publications on radiolucent jaw lesions, as indexed by the Web of Science Core Collection database. The mentions of radiolucent jaw lesions were extracted from the complete bibliographic records of the publications, and co-word analyses were conducted with the aid of VOSviewer. (3) Results: Based on 1897 papers, visualization maps were synthesized to evaluate co-occurrences of the radiolucent jaw lesions. Ameloblastoma was frequently mentioned together with odontogenic keratocyst, dentigerous cyst, and radicular cyst. Osseous dysplasia was co-mentioned with osteomyelitis, ossifying fibroma, odontoma, fibrous dysplasia, and apical periodontitis. (4) Conclusions: The co-word analysis, a form of bibliometric analysis, could demonstrate a relatedness of radiolucent jaw lesions that could be considered at differential 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.

Multimodular Assessment of a Traumatic Bone Cyst Overlapped with Apical Periodontitis

Traumatic bone cyst (TBC), a “pseudocyst” that usually affects long bones, is a rare lesion among cystic lesions in the jaws. The most commonly affected site is the posterior mandible. Most of the time, TBC is asymptomatic and discovered during routine radiographic examination. The treatment recommended for TBC is surgical exploration followed by curettage of the bony walls, which also serves as a diagnostic procedure. A 27-year-old Caucasian male with a noncontributory medical history was referred to our department for the endodontic evaluation of the mandibular right first and second molars, which were connected to an extensive asymptomatic osteolytic lesion. A multimodular diagnostic assessment involving CBCT imaging, ultrasound, and histopathologic examination led to a definite diagnosis of a TBC overlapping with apical periodontitis (AP). Subsequently, a multidisciplinary treatment approach was performed, including surgical excision and biopsy of the lesion, endodontic retreatment of the right mandibular first molar, and postsurgical root canal treatment of the second molar. During the follow-up period of five years, the patient was reassessed periodically once a year and showed, in the absence of signs and symptoms, progressive healing of the affected area. The present article reports a case following the CARE guidelines of a TBC combined with AP where a multimodular diagnostic assessment was performed and discusses the possible pathogenetic mechanisms involved in its generation.

Unilocular Radiolucent Lesions of the Jaws: a Retrospective Panoramic and Cone Beam Computed Tomography Evaluation

Background/Aim: The aim of this study was to evaluate and compare the imaging characteristics of common, radiolucent, unilocular, intraosseous lesions of the jaws using both panoramic radiography and cone beam computed tomography (CBCT); also, to evaluate sufficiency of panoramic radiography in determining characteristic features of jaw lesions.

Material and Methods: Retrospectively selected images of 57 patients with histopathology results were evaluated by two oral radiologists. The lesions were assessed based on shape, location, borders, relationship with the mandibular canal, presence of destruction of cortical bone, and expansion of cortical bone, and presence of an unerupted tooth related to the lesion. In addition, the widest areas of the lesions were measured. A total of 9 (15.8%) odontogenic keratocysts, 9 (15.8%) apical granulomas, 24 (42.1%) radicular cysts, 12 (21.0%) dentigerous cysts and 3 (5.2%) central giant cell granulomas in 57 patients (20 women, 37 men) with a mean age of 36.93 ± 17.96 years were included. Fifty-seven CBCT and 56 panoramic images of these patients were evaluated.

Results: Twenty-nine (50.8%) lesions were in the mandible and 28 (49.2%) in the maxilla. A statistically significant difference was determined for the areas in CBCT images (p=0.007).

Conclusions: Panoramic radiography is not as successful as CBCT in demonstrating some characteristics of the lesions, such as expansion and destruction. The area measurements may be beneficial in establishing the differential diagnosis of the lesion.

The many faces of periapical inflammation

Dental periapical inflammation is common and can present with a wide variety of symptoms and signs. These include jaw pain and local soft-tissue inflammation, which may be obviously dental in origin; however, the presentation may also be with a painless mass or draining cutaneous sinus, with facial or ear pain or with symptoms of sinusitis, when the dental cause is not clinically obvious. Radiologists are often the first to recognise the dental source of symptoms in these cases. This recognition requires an awareness of the varied manifestations of periapical sepsis and careful systematic review of the teeth and jaws. The causative periapical lesion may be small and subtle, and there is not always a macroscopic defect in the cortical bone between the lesion and surrounding soft-tissue inflammation. The origin of the referral and the initial imaging technique used can vary. Dental periapical inflammation can also be an incidental finding on imaging. In these cases, it should not be mistaken for more sinister pathology and its presence should be conveyed to the referrer so that appropriate dental treatment can be initiated: this is especially important in patients with malignancy in whom radiotherapy is planned. In cases of severe odontogenic soft-tissue sepsis, a review of the airway and major blood vessels is important. We present cases to illustrate the wide range of clinical and radiological manifestations of periapical inflammatory pathology.

Imaging Characteristic of 11 Lesions of Odontogenic Keratocyst in the Indian Subpopulation: A Cone-Beam Computed Tomography Experience

Background:

The clinical feature and radiographic appearance of orthokeratinized odontogenic keratocyst (OKC) are not characteristic, which may lead to the misdiagnosis. The radiographic appearance of OKC may range from a small unilocular radiolucency to a large multilocular radiolucency, resembling other odontogenic cysts and tumors.

Aim:

The aim was to illustrate the characteristic feature of OKC presented on the digital panoramic radiograph and cone-beam computed tomography (CBCT), which may provide great value for the differential diagnosis and the treatment planning and also to compare the various radiographic features of OKC in CBCT and digital panoramic radiograph.

Materials and Methods:

Digital panoramic and CBCT records of seven cases, with 11 lesions of OKC were analyzed retrospectively from the patients' database from our institute (2014 to 2016), which was histopathologically diagnosed as OKC.

Results:

The mean age of the patients was 24.1 years, and the female-to-male ratio was 3: 4. Six of 11 lesions were localized within the mandible, and five lesions were in the maxilla.

Conclusion:

The presurgical assessment with radiological information is extremely important for treatment planning, and CBCT provides us with an accurate and faster three-dimensional representation of a lesion at a lower dose and cost, but the role of panoramic radiograph cannot be refuted.

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.

The effectiveness of ultrasound examination to assess the healing process of bone lesions of the jaws: a systematic review

OBJECTIVE

To assess the potential of ultrasound examination (USE) as an adjunctive method to conventional radiology to evaluate the healing processes occurring after the treatment of bone lesions of the jaws. The research question was: what is the effectiveness of USE to evaluate the healing of intra-osseous bone lesions when compared to radiological or clinical examination?

MATERIALS AND METHODS

Six databases (PubMed, the Web of Science, Scopus, Embase, the Cochrane Library, and Best Evidence) were searched from their inception (PROSPERO CRD42019134482). A quality assessment was performed combining the Downs and Black tool and the Newcastle-Ottawa scale. The risk of bias was calculated using the Cochrane collaboration tool to assess the risk of bias.

RESULTS

A total of 4404 records were screened, and 7 studies meeting the inclusion criteria were included in the systematic review. USE allowed to evaluate the healing of jaw bone lesions by assessing their reduction in size, the increase in echogenicity of the affected area, and the progressive decrease\disappearance of the vascular flow signal within the lesions.

CONCLUSIONS

USE implemented with color power Doppler is an advanced imaging technique feasible to monitor the early and long-term response of the intra-osseous lesions of the jaws to both surgical and nonsurgical treatment.

CLINICAL RELEVANCE

This systematic review brought evidence that USE can constitute a safe alternative imaging technique in the dental clinical practice for the management of central lesions of the maxillary bones.

Incidental findings in a consecutive series of digital panoramic radiographs

Purpose

The aim of this study was to determine the prevalence of incidental findings (IFs) on digital dental panoramic radiographs (DPRs) of asymptomatic patients attending a general dental practice.

Materials and Methods

This was a retrospective study of 6,252 consecutive digital (photostimulatable phosphor) DPRs of patients who visited a Canadian general dental practice for a complete new patient examination. The IFs were grouped into dental-related anomalies, radiopacities and radiopacities in the jaws, changes in the shape of the condyles, and other findings in the jaws, such as tonsilloliths and mucosal antral pseudocysts. Their prevalence was determined.

Results

Thirty-two percent of the DPRs showed at least 1 IF. The highest prevalence was found for dental-related anomalies (29% of all DPRs), of which impacted teeth were the most prevalent finding (24% of all DPRs), followed by idiopathic osteosclerosis (6% of all DPRs). A lower prevalence was noted for tonsilloliths (3%), and the prevalence of root tips, mucosal antral pseudocysts, and anomalies in condylar shape was approximately 1% each.

Conclusion

The observed prevalence of 32.1% for IFs of any type underscores the need for a dental practitioner to review the entire DPR when a patient presents for an initial dental examination (or check-up) or for dental hygiene. Only a single IF (a central giant cell granuloma) provoked alarm, as it was initially considered malignant. Similarly, impacted teeth and suspected cysts need careful evaluation upon discovery to determine how they may be optimally managed.

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.

Imaging of odontogenic sinusitis

The aetiological relationship between dental disease and procedures and mucosal disease within the maxillary sinus has received extensive attention in the recent otolaryngological and dental literature. In contrast, the concept of an odontogenic cause for sinusitis is not well appreciated by radiologists. Review of the maxillary dentition, the alveolar process, and the relationship of the tooth roots to the floor of the maxillary sinus should be an integral part of interpretation of imaging of the paranasal sinuses. The pathogenesis, clinical presentation, and imaging features of rhinogenic and odontogenic sinusitis are discussed and compared. Clinical definitions of rhinosinusitis are explained and the huge impact on healthcare of this disease is briefly discussed. Periapical inflammatory lesions, post-extraction oroantral communication, and procedures used to augment the alveolar process prior to placement of dental implants are the commonest causes of odontogenic sinusitis. Current estimates are that an odontogenic cause for maxillary sinusitis is present in 25-40% of cases. The incidence of odontogenic sinusitis is rising, extension outside the maxillary sinus is common, and the diagnosis is often delayed, resulting in inappropriate and failed treatment. Differentiation of rhinological and odontogenic causes of sinusitis is usually difficult on clinical grounds and imaging plays a key role in the distinction.

Extranodal lymphoma arising within the maxillary alveolus: a systematic review

Objectives

Extranodal lymphomas affecting the head and neck infrequently arise within the jaw bones. Although clinical examination and conventional radiography may initially suffice for such lesions arising within the mandible, those arising within the maxillary alveolus generally require cross-sectional imaging because of the complex anatomy of this region. This study was performed to determine the prevalence, demographic characteristics, and clinical presentations of these lesions and the imaging modalities used for their diagnosis.

Study design

A systematic review (SR) on case series and another SR on case reports were performed to investigate the demographic, clinical, and radiological features of extranodal lymphomas arising within the maxillary alveolus.

Results

Most case series were derived from just four nations, whereas the case reports were derived from a wider range of ethnicities. The more detailed case reports significantly reported at least one imaging modality. Most patients were aware of their lesions for nearly 2 months before presentation. The most frequent symptom was swelling. Most case reports included a provisional diagnosis, the most frequent of which was dental infection followed by squamous cell carcinoma.

Discussion

Extranodal lymphomas arising within the maxillary alveolus were sufficiently frequent in four communities to be reported in two or more case series, and the occasional single case report indicated that such lesions are more widespread globally. Although the SR on case series revealed differences in the relative period prevalence and maxillary/mandibular ratio, the SR on case reports revealed details of the clinical presentation and imaging modalities used.

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.

Cone-beam CT in paediatric dentistry: DIMITRA project position statement

DIMITRA (dentomaxillofacial paediatric imaging: an investigation towards low-dose radiation induced risks) is a European multicenter and multidisciplinary project focused on optimizing cone-beam CT exposures for children and adolescents. With increasing use of cone-beam CT for dentomaxillofacial diagnostics, concern arises regarding radiation risks associated with this imaging modality, especially for children. Research evidence concerning cone-beam CT indications in children remains limited, while reports mention inconsistent recommendations for dose reduction. Furthermore, there is no paper using the combined and integrated information on the required indication-oriented image quality and the related patient dose levels. In this paper, therefore, the authors initiate an integrated approach based on current evidence regarding image quality and dose, together with the expertise of DIMITRA's members searching for a state of the art. The aim of this DIMITRA position statement is to provide indication-oriented and patient-specific recommendations regarding the main cone-beam CT applications in the pediatric field. The authors will review this position statement document when results regarding multidisciplinary approaches evolve, in a period of 5 years or earlier.

Trends in maxillofacial imaging

Maxillofacial imaging encompasses radiology of the teeth and jaws, including the temporomandibular joints. Modalities used include intra-oral radiographs, panoramic tomography, cephalograms, cone-beam computed tomography, computed tomography, magnetic resonance imaging, ultrasound, and radionuclide imaging. Common indications for imaging are impacted and supernumerary teeth, dental implants, inflammatory dental disease, and fibro-osseous lesions, cysts, and masses of the jaws. Osteonecrosis of the jaws may follow radiotherapy or the use of bisphosphonates and other drugs. Imaging of the temporomandibular joints and the potential role of imaging in obstructive sleep apnoea are also discussed.