Odontogenic Cysts and Tumors

Odontogenic cystic lesion segmentation on cone-beam CT using an auto-adapting multi-scaled UNet

Objectives

Precise segmentation of Odontogenic Cystic Lesions (OCLs) from dental Cone-Beam Computed Tomography (CBCT) is critical for effective dental diagnosis. Although supervised learning methods have shown practical diagnostic results in segmenting various diseases, their ability to segment OCLs covering different sub-class varieties has not been extensively investigated.

Methods

In this study, we propose a new supervised learning method termed OCL-Net that combines a Multi-Scaled U-Net model, along with an Auto-Adapting mechanism trained with a combined supervised loss. Anonymous CBCT images were collected retrospectively from one hospital. To assess the ability of our model to improve the diagnostic efficiency of maxillofacial surgeons, we conducted a diagnostic assessment where 7 clinicians were included to perform the diagnostic process with and without the assistance of auto-segmentation masks.

Results

We collected 300 anonymous CBCT images which were manually annotated for segmentation masks. Extensive experiments demonstrate the effectiveness of our OCL-Net for CBCT OCLs segmentation, achieving an overall Dice score of 88.84%, an IoU score of 81.23%, and an AUC score of 92.37%. Through our diagnostic assessment, we found that when clinicians were assisted with segmentation labels from OCL-Net, their average diagnostic accuracy increased from 53.21% to 55.71%, while the average time spent significantly decreased from 101s to 47s (P<0.05).

Conclusion

The findings demonstrate the potential of our approach as a robust auto-segmentation system on OCLs in CBCT images, while the segmented masks can be used to further improve OCLs dental diagnostic efficiency.

Radicular Cyst: The Sequelae of Untreated Caries

A radicular cyst is characterized as an odontogenic cyst of inflammatory origin that develops from Malassez epithelial rests in the periodontal ligament as the consequence of dental pulp inflammation. The cyst commenced in the carious tooth and spread to the periodontal and periapical regions. The majority of these lesions appear as precise radiolucencies and encompass their entire apex. The cystic lesion, which is also called a root-end cyst or periapical cyst, is sometimes referred to as a true cyst because it is lined by fluid epithelium. There are several treatment options to address radicular cysts, including surgical and nonsurgical methods. In this case study, we described the clinical observation of the cyst. The cyst typically manifests in later life due to its prolonged etiology. The maxillary anterior region is the most frequently utilized site.

A Large Follicular Dentigerous Cyst: A New Multi-portal Access: Intraoral and Endoscopic Technique

Background

The standard treatment for a dentigerous cyst of maxilla is a surgical enucleation, the extraction of the tooth. In the case of cysts involving the maxillary sinus, a Caldwell-Luc approach is used. In case of large cysts, its marsupialization is carried out in order to reduce the bone defect, followed by enucleation and extraction of the tooth.

Methods

This is a case of a large follicular dentigerous cyst of upper jaw with 18 ectopic tooth within the maxillary sinus, treated in our Unit.

Results

We decided to perform a multi-portal access, the intraoral endoscopic-assisted technique; an intraoral approach has been performed, but less demolishing than the routine intraoral approach, through the anterior wall of the maxillary sinus, already eroded by the lesion. The lesion was very large, occupying the entire maxillary cavity. For this reason, by means of the intraoral approach alone, it was extremely difficult to remove the lesion in its entirety. The endoscopic-assisted technique was combined with intraoral approach. The lesion extended to the maxillary ostium. This did not allow to reach the ostium through the classic endoscopic approach. Endonasal endoscopic access was used both to enucleate the cyst, that was adherent to the orbital floor and soft tissues of the OMC (osteomeatal complex), and to restore the physiological drainage of the maxillary sinus.

Conclusions

We decided to perform a combined intraoral and endoscopic approach to allow a complete excision of the cystic lesion, without being very demolishing and taking advantage of the bone erosion already caused by the large cyst.

Lung Cancer Cells Infiltration into a Mandibular Follicular Cyst

Introduction

The oral cavity is a rare site for other organs' tumor metastases. The incidence rate ranges from 1% to 3% of all oral malignancies. Metastases more frequently localize in the mandible, especially in the molar area. Metastases within odontogenic cysts are extremely rare, thus in the literature, only a few cases have been reported. The follicular cyst is one of the most frequent cysts of the jaws. Radiologically it shows as a unilocular lesion with a sclerotic border, characterized by a homogenous radiolucency that incorporates the crown of the unerupted tooth.

Methods

A 76-year-old female patient, affected by stage IV of lung adenocarcinoma, reported pain on the left mandible border, alongside lip dysesthesia. The ortho-panoramic radiograph showed a follicular cyst in the posterior left side of the mandible, with involvement of the ascending branch region. The cyst was surgically removed together with the impacted tooth. A histopathological examination of the specimen confirmed the diagnostic suspect of a follicular cyst, but in the cystic wall, focal infiltration of epithelial neoplastic cells was also found. The immunohistochemical analysis showed the presence of three different markers: CK 7+, TTF1+/-, and P40-. These markers identify the cells as metastatic lung carcinoma.

Results

Secondary tumor spreading in the jaws' area is rare (3% of all malignant lesions). Despite odontogenic cysts can undergo a dysplastic transformation (affecting the epithelial covering in ≤1% of the cases), infrequently these neoplastic cells can be related to secondary tumor spreading in a cystic wall. This report describes a metastatic localization within a mandibular follicular cyst.

Conclusions

Malignant cancers' metastasis in the oral district remains a rare and unexplored condition, especially when metastases are located in odontogenic cysts. In this circumstance, surgical removal and histopathological examination are strongly recommended.

Prevalence of oral and maxillofacial lesions in children and adolescents at a regional Brazilian oral pathology service: a retrospective study and the relevant literature review

PURPOSE

This study assessed the prevalence of maxillofacial lesions in children, i.e., 0-9 years, and adolescents, i.e., 10-19 years, in a Brazilian Oral Pathology Service and compared results with available literature.

METHODS

Clinical and histopathological records from January 2007 to August 2020 were analysed and a literature review investigating maxillofacial lesions in paediatric populations was also performed.

RESULTS

Overall, "reactive salivary gland lesions" and "reactive connective tissue lesions" were the most prevalent group of soft tissue lesions, affecting children and adolescents equally. From these, mucocele and pyogenic granuloma were the most prevalent histological diagnoses, respectively, regardless of age. These findings were consistent with the 32 studies included. Considering intraosseous lesions, "odontogenic cysts" and "periapical inflammatory lesions" were the most prevalent groups, with no relevant differences between age groups, except for the odontogenic keratocyst, which was more prevalent in adolescents. Moreover, several odontogenic tumours, such as ameloblastic fibroma and odontogenic myxoma, were significantly more prevalent in children.

CONCLUSION

Most maxillofacial lesions presented a similar prevalence between children and adolescents. Reactive salivary gland lesions and reactive connective tissue lesions were the prevailing diagnostic categories, regardless of age. Some odontogenic tumours and the odontogenic keratocyst showed significantly different frequencies across these age groups.

Application of Cone Beam Computed Tomography in Risk Assessment of Lower Third Molar Surgery

Risks of lower third molar surgery like the inferior alveolar nerve injury may result in permanent consequences. Risk assessment is important prior to the surgery and forms part of the informed consent process. Traditionally, plain radiographs like orthopantomogram have been used routinely for this purpose. Cone beam computed tomography (CBCT) has offered more information from the 3D images in the lower third molar surgery assessment. The proximity of the tooth root to the inferior alveolar canal, which harbours the inferior alveolar nerve, can be clearly identified on CBCT. It also allows the assessment of potential root resorption of the adjacent second molar as well as the bone loss at its distal aspect as a consequence of the third molar. This review summarized the application of CBCT in the risk assessment of lower third molar surgery and discussed how it could aid in the decision-making of high-risk cases to improve safety and treatment outcomes.

Conservative Algorithm for the Treatment of Locally Aggressive Tumors: A Retrospective Study

Background

Aggressive benign odontogenic neoplasms are a group of lesions that have the potential to grow to an enormous size resulting in bony deformities, locally aggressive behavior and have high recurrence rate. Ameloblastomas, keratocystic odontogenic tumors, etc., are included under this group of lesions. Treatment of these lesions is challenging owing to their particular characteristics including high recurrence rate, locally aggressive behavior, etc.

Materials and Methods

A retrospective study was conducted in 40 patients who had undergone enucleation and open packing as treatment for benign aggressive neoplasms in the department of oral and maxillofacial surgery.

Results

In the study, all the cases were followed up for a minimum of 5 years clinically and radiographically. Satisfactory bone healing was noted with no evidence of recurrence in all cases.

Conclusion

Enucleation followed by open packing with iodoform is an excellent conservative modality with proven minimal rate of recurrences in 5-year period.

Immunoexpression of stem cell markers SOX-2, NANOG AND OCT4 in ameloblastoma

Background

Ameloblastoma (AME) is characterized by a locally invasive growth pattern. In an attempt to justify the aggressiveness of neoplasms, the investigation of the role of stem cells has gained prominence. The SOX-2, NANOG and OCT4 proteins are important stem cell biomarkers.

Methodology

To verify the expression of these proteins in tissue samples of AME, dentigerous cyst (DC) and dental follicle (DF), immunohistochemistry was performed and indirect immunofluorescence were performed on the human AME (AME-hTERT) cell line.

Results

Revealed expression of SOX-2, NANOG and OCT4 in the tissue samples and AME-hTERT lineage. Greater immunostaining of the studied proteins was observed in AME compared to DC and DF (p < 0.001).

Conclusions

The presence of biomarkers indicates a probable role of stem cells in the genesis and progression of AME.

A custom-made removable appliance for the decompression of odontogenic cysts fabricated using a digital workflow

OBJECTIVES

This case series aimed to assess the feasibility of a custom-made decompression appliance fabricated using a digital workflow to decompress odontogenic cysts. Additionally, the treated cysts were assessed for volumetric changes.

METHODS

A three-dimensional (3D) reconstruction software (CoDiagnostiX version 10.4) was used to obtain the master cast STL (Standard Tessellation Language) file by placing a customized virtual implant to create a recess for the tube of the decompression device. The decompression appliance was planned using Dental Wings Open Software (DWOS). Following rapid prototyping, the tube of the appliance was perforated using round burs. In cases where the appliances were designed to replace teeth, denture teeth were added using the conventional workflow. The appliances were delivered on the day of the cystostomy. Following decompression, cyst enucleation was performed. Cyst volume was assessed by manual segmentation of pre- and post-operative cone-beam computed tomography (CBCT) reconstructions using slice-by-slice boundary drawing with a scissors tool in the 3DSlicer 4.10.2 software. Percentage of volume reduction was calculated as follows: volume reduction/pre-operative volume × 100.

RESULTS

Six odontogenic cysts in six patients (5 male, 1 female; age 40 years, range: 15-49 years) with a pre- and post-operative cyst volume of 5597 ± 3983 mm³ and 2330 ± 1860 mm³ respectively (p < 0.05) were treated. Percentage of volume reduction was 58.84 ± 13.22 % following a 6-month-long decompression period.

CONCLUSIONS

The digital workflow described in this case series enables the delivery of decompression appliances at the time of cystostomy, thus effectively reducing the volume of odontogenic cysts. The resulting bone formation established a safe zone around the anatomical landmarks; therefore, during enucleation surgery, complications to these landmarks can be avoided.

A Rare Case of Peripheral Compound Odontoma and Review of the Literature

Peripheral or extraosseous odontogenic tumors are rare oral soft tissue enlargements which demonstrate the same histologic features of their intraosseous counterparts but emerge in gingiva and mucosa. In this paper we report a case of peripheral odontoma in a 12-years-old female patient presented asymptomatic swelling in the palatal site. After the clinical and radiographic examination, excisional biopsy was applied to the lesion located entirely in the soft tissue of maxillary incisors. Histopathologically presence of tooth-like structures containing dentin with regular canals and partly enamel matrix were observed. Our aim is to present the extremely rare case of peripheral odontoma and to review the literature for demonstrating the frequency and clinicopathologic features of this entity.

The Prevalence of EBV and KSHV in Odontogenic Lesions

OBJECTIVES

Odontogenic lesions evolve as a result of altered dental development. This study aimed to evaluate the prevalence and the coinfection of Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV) in radicular cysts, dentigerous cysts, odontogenic keratocysts, and ameloblastomas.

METHODS

Polymerase chain reaction (PCR) was used to analyse 66 cases of odontogenic lesions for the presence of EBV-DNA and KSHV-DNA. These lesions were 15 radicular cysts, 16 dentigerous cysts, 18 odontogenic keratocysts, and 17 ameloblastomas.

RESULTS

EBV-DNA was detected in 24 (36.4%) of the studied samples as follows: 6 samples (40.0%) of radicular cysts, 4 (25.0%) of dentigerous cysts, 10 (55.6 %) of odontogenic keratocysts, and 4 (23.5%) of ameloblastomas (P = .168). KSHV-DNA was found in 16 (24.2%) of the studied samples as follows: 1 sample (6.7%) of radicular cysts, 6 (37.5%) of dentigerous cysts, 8 (44.4 %) of odontogenic keratocysts, and 1 (5.9%) of ameloblastomas (P = .001). Additionally, EBV and KSHV were positively correlated in all studied samples (P = .002).

CONCLUSIONS

Both EBV and KSHV are found in odontogenic cysts and ameloblastomas. KSHV and EBV are more prevalent in odontogenic keratocysts than in other studied odontogenic lesions. Further, there is a high prevalence of EBV and KSHV coinfection in odontogenic cysts and ameloblastomas.

Epidemiological evaluation of jaw cysts according to the new WHO classification: a 30-year retrospective analysis

The aim of the present study was to analyze the epidemiology of maxillofacial odontogenic and non-odontogenic cysts diagnosed for 30 years in a Brazilian population. A retrospective descriptive cross-sectional study was performed. Biopsy records were obtained from the archives of a Brazilian referral center between 1989 and 2019. Data regarding age, gender, anatomical location, and histopathological diagnosis were collected and categorized. Further, a literature search for similar studies was performed. A total of 6.994 biopsy records were evaluated, but only 367 (5.24%) cases were classified as odontogenic cysts (OC) or non-odontogenic cysts (NOC). Among all cystic lesions, 341 cases (92.9%) were OC and 26 cases (7.1%) were NOC. These lesions were more common in females (n = 208 / 56.67%) and located mostly in the mandible (n = 195 / 53.1%). In patients with OC, the radicular cyst was the most frequent (n = 134 / 36.5%), followed by the dentigerous cyst (n = 101 / 27.5%) and the odontogenic keratocyst (n = 52 / 14.2%). Patients with NOC had a higher frequency of epidermoid cyst (n = 12 / 3.3%), oral lymphoepithelial cyst (n = 7 / 1.9%), and nasopalatine duct cyst (n = 4 / 1.1%). The OCs were more prevalent than NOCs, and inflammatory cysts were the most common among all the OCs.

Multidisciplinary approaches to odontogenic lesions

PURPOSE OF REVIEW

To give an overview of technical considerations and relevant literature in the management odontogenic pathology with involvement of the maxillary sinus.

RECENT FINDINGS

Infections, cysts, benign neoplasms (odontogenic and nonodontogenic), and inflammatory conditions impact the maxillary sinus in various ways, could result in significant expansion within the maxillary sinus and significant infections.

SUMMARY

This manuscript provides an overview of common pathologic entities of the oral cavity proper that impacts the maxillary sinus health, with discussion of the role of the otorhinolaryngologist and the dental specialist.