Marsupialisation for the treatment of unicystic ameloblastoma of the mandible: a long-term follow up of 116 cases

A three-dimensional quantitative assessment on bony growth and symmetrical recovery of mandible after decompression for unicystic ameloblastoma

Unicystic ameloblastoma (UAM) of the jaw can be effectively reduced in volume through decompression, which promotes bone regeneration and restores jaw symmetry. This study quantitatively evaluated changes in mandible volume and symmetry following decompression of mandibular UAM. This study included 17 patients who underwent surgical decompression followed by second-stage curettage for mandibular UAM. Preoperative and postoperative three-dimensional computed tomography (CT) images were collected. Bone volume and the area of cortical perforation were measured to assess bone growth during decompression. Mandibular volumetric symmetry was analyzed by calculating the volumetric ratio of the two sides of the mandible. Twelve pairs of landmarks were identified on the surface of the lesion regions, and their coordinates were used to calculate the mean asymmetry index (AI) of the mandible. Paired t-tests and the Mann-Whitney U test were used for statistical analysis, with p < 0.05 considered indicative of statistical significance. The mean duration of decompression was 9.41 ± 3.28 months. The mean bone volume increased by 8.07 ± 2.41%, and cortical perforation recovery was 71.97 ± 14.99%. The volumetric symmetry of the mandible improved significantly (p < 0.05), and a statistically significant decrease in AI was observed (p < 0.05). In conclusion, UAM decompression enhances bone growth and symmetry recovery of the mandible. The present evaluation technique is clinically useful for quantitatively assessing mandibular asymmetry.

Treatment of benign maxillomandibular osteolytic lesions larger than 4 cm: A systematic review

OBJECTIVE

This systematic review aimed to assess the different treatments of benign maxillo-mandibular radiolucent bone lesions over 4 cm to propose a management algorithm.

STUDY DESIGN

A literature search was conducted using MEDLINE/PubMed, Scopus, Google Scholar, Virtual Health Library databases, and gray literature. Randomized or non-randomized clinical trials and case series with 10 or more patients with a minimum follow up of 1 year, published in French or English until August 2023, were included. The risk of bias was assessed for all papers included.

RESULTS

Of 1433 records identified, 22 were included in this review, reporting data from 1364 lesions. Ameloblastoma was the most common lesion (51.22%) and mandible was the most common site (81.21%). Initial conservative treatment was prevalent (71.04%). Recurrence was higher after conservative (13.8%) than after radical treatments (6.5%). Multilocularity, cortical perforation, dental element preservation were linked to a higher recurrence risk.

CONCLUSION

This study has shown importance of understanding specific characteristics and recurrence risk in benign maxillomandibular osteolytic lesions. Multidisciplinary team approval, personalized approach based on lesion type and patient are crucial. The presence of at least one risk factor could lead to therapeutic decision. Despite limitations, the study informed lesion management and provided precise recommendations.

The 'D-M-C' strategy for conventional ameloblastoma of the mandible: a retrospective study

The purpose of this multicentre study was to evaluate the efficacy of the 'dredging-marsupialization-curettage' (D-M-C) strategy in the treatment of conventional intraosseous ameloblastoma of the mandible. A total of 31 patients from three institutions, who had a pathological diagnosis of conventional ameloblastoma of the mandible, were treated with the D-M-C strategy. The surgical protocol comprised a dredging and marsupialization (D-M) step, with additional D-M steps as required. The patients then underwent curettage (C) once an obvious effect of the D-M step had been achieved during follow-up. Eight patients were followed up for ≥36 months but <60 months, while 23 were followed up for ≥60 months. Nineteen of the 23 patients followed up for ≥60 months were disease-free at the last follow-up, with no evidence of recurrence. The D-M step is effective for reducing the tumour size and preserving vital structures. The D-M-C surgical strategy may be a feasible treatment option for conventional ameloblastoma of the mandible.

Deep Circumflex Iliac Artery Flap Reconstruction in Brown Class I Defect of the Mandible Using a Three-Component Surgical Template System

BACKGROUND

Computer-assisted surgery is widely used in mandibular reconstruction, but the process is not well described for cases using the deep circumflex iliac artery flap (DCIA) as the donor site. This study aimed to present a DCIA-based three-component surgical template system (3-STS) in patients with a mandibular Brown class I defect.

METHODS

This retrospective cohort study compared clinical outcomes of mandibular reconstruction with DCIA flap using 3-STS or conventional surgical templates. The primary outcome of the study was the accuracy of reconstruction, and the secondary outcomes included surgical time and bone flap ischemia time. Surgery-related parameters and functional outcomes were also recorded and compared.

RESULTS

Forty-four patients (23 in the 3-STS group and 21 in the control group) between 2015 and 2021 were included. Compared with the control group, the 3-STS group had higher accuracy of reconstruction, indicated by lower deviation in absolute distance (1.45 ± 0.76 mm versus 2.02 ± 0.89 mm; P = 0.034), and less deviation in coronal and sagittal angles (0.86 ± 0.53 degree versus 1.27 ± 0.59 degrees, P = 0.039; and 2.52 ± 1.00 degrees versus 3.25 ± 1.25 versus, P = 0.047) between preoperative and postoperative computed tomographic imaging. Surgical time and bone flap ischemia time were significantly reduced in the 3-STS group compared with the control group (median time, 385 minutes versus 445 minutes and 32 minutes versus 53 minutes, respectively; P < 0.001). In addition, masseter attachment was preserved in the 3-STS group but not in the control group. No differences were found in adverse events or other clinical variables.

CONCLUSION

The 3-STS can improve accuracy, simplify intraoperative procedures to increase surgical efficiency, and preserve functionality in mandibular reconstruction for Brown class I defects.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Clinicopathologic Profile and Surgical Modalities in Mandibular Ameloblastoma: A Descriptive Study

BACKGROUND

Ameloblastoma is a benign neoplasm composed of epithelial tissue with invasive and infiltrative behavior at the local level and a high recurrence rate, with various histopathologic patterns and clinical forms. Approximately 85% of conventional ameloblastomas occur in the mandible, most often in the body, angle, and ascending ramus area. The treatment modalities include both conservative and radical treatments. Postoperative follow-up is most important in the treatment of ameloblastoma.

AIMS AND OBJECTIVES

To describe the clinicopathologic profile of mandibular ameloblastoma in patients undergoing different surgical modalities. The primary objective was to describe the clinicopathologic profile and surgical management of mandibular ameloblastoma in patients aged ≥18 years, who had reported to a tertiary dental care center for follow-up during the study period. The secondary objective was to describe the distribution of comorbidities associated with different surgical modalities and reconstructive methods.

SUBJECTS AND METHODS

A total of 34 patients with mandibular ameloblastoma who underwent various surgical modalities between 2011 and 2021 were studied. Information was collected using a predesigned proforma and statistically analyzed.

RESULTS

Thirty-four review cases of ameloblastoma were included in the study. The patients were analyzed concerning age, sex, site, size, clinical presentation, radiographic pattern, histopathologic subtype, type of surgery, and associated comorbidities. Most cases of mandibular ameloblastoma involve the age of 16 to 55 years. The mean age of occurrence was found to be 35.5±13.2. A female preponderance, a tumor size range of 2 to 4 cm, a multicystic variant, involvement of the mandibular body in the premolar-molar area, root resorption, cortical perforation, and a follicular type of histopathologic pattern were the common presentations. Isolated anterior tumors restricted to the incisor/canine region were not found. The common surgical modalities undertaken were conservative methods such as enucleation, and chemical cauterization, and radical methods such as marginal mandibulectomy and segmental resection. Reconstruction using a titanium plate or free fibular graft was performed in the indicated cases. The common comorbidities included difficulty in chewing and loss of facial contour. Recurrence after surgical treatment was rare. Only 9% of cases developed a recurrence within 5 years. No recurrence was noted in cases treated with radical treatment, whereas 50% of cases treated with conservative methods showed recurrence.

CONCLUSION

The age of occurrence, site, and size of the tumor, cortical perforation, root resorption, histopathologic type, and radiographic patterns are widely considered factors in devising a treatment plan for mandibular ameloblastoma. However, there may be rare instances where these tumors behave differently regardless of their innocuous clinicopathologic presentation. Surgical procedures such as segmental resection and marginal mandibulectomy were found to be promising for the eradication of the tumor, and prevention of recurrences and metastasis. However, conservative measures such as enucleation and chemical cauterization were fraught with an increased risk of tumor recurrence and metastasis. Future studies with a larger sample size should focus on the clinicopathologic characteristics of ameloblastoma to elucidate its varied behavior and develop newer and advanced treatment modalities that would provide better surgical and postsurgical outcomes in affected patients.

Volumetric change of bony cavity and shrinkage speed after marsupialization for odontogenic keratocyst and unicystic ameloblastoma

The aim of this study was to evaluate the efficacy of marsupialization treatment for odontogenic keratocyst (OKC) and unicystic ameloblastoma (UA) based on the three-dimensional volumetric change over time, and to determine the difference between OKC and UA in terms of the absolute volume reduction (AVR) and absolute shrinkage speed (ASS), and whether they are correlated with the preoperative volume, time after marsupialization (time between marsupialization and second treatment), and patient age. This was a retrospective cohort study with a sample size of 60 patients: 29 with OKC and 31 with UA. Pre- and post-marsupialization cone beam computed tomography images were analysed using Mimics software. The volume reduction and shrinkage speed were analysed and correlated with the preoperative volume, time after marsupialization, and demographic data. Descriptive univariable and multivariable statistics were computed; significance was set at P ≤ 0.05. The mean percentage volume reduction after marsupialization was 67.6 ± 9.6% for OKC and 63.3 ± 20.1% for UA. There was no significant difference in AVR or ASS between the OKC and UA groups. For OKC and UA, the preoperative volume (both P < 0.001) and time after marsupialization (P = 0.024 and P < 0.001, respectively) were associated with AVR. Moreover, for OKC and UA, the preoperative volume and time after marsupialization were also significantly associated with the ASS (all P < 0.001). For both lesions, patient age was not significantly related to AVR or ASS. Marsupialization appears to be a viable option to decrease the volume of OKC and UA. Age was found not to be associated with the volume reduction of either UA or OKC.

Ameloblastoma: An Updated Narrative Review of an Enigmatic Tumor

Ameloblastoma is one of the most common benign odontogenic tumors of the jaw that constitutes about 10% of all tumors that arise in the mandible and maxilla. It is a slow-growing but locally invasive tumor that presents with painless swelling of the mandible or maxilla. The World Health Organization (WHO) classification of 2017 describes ameloblastomas of the following four types: ameloblastoma; unicystic ameloblastoma; extraosseous/peripheral ameloblastoma; and metastasizing ameloblastoma. The diagnosis of ameloblastoma requires computerized tomography (CT) imaging as well as a biopsy. A biopsy is helpful in differentiating ameloblastoma from ossifying fibroma, osteomyelitis, giant cell tumor, cystic fibrous dysplasia, myeloma, and sarcoma. The best treatment of ameloblastoma is aggressive en bloc resection with simultaneous reconstruction. The high recurrence rate and large tissue defects have been long-standing issues in the treatment of ameloblastoma. Recent molecular developments strongly suggest the possibility of targeted therapy with better outcomes in ameloblastomas. We present a detailed updated narrative review of our current understanding and management of this enigmatic tumor.

αTAT1-induced tubulin acetylation promotes ameloblastoma migration and invasion

Ameloblastoma (AB) is the most common benign epithelial odontogenic tumor occurring in the jawbone. AB is a slowly growing tumor but sometimes shows a locally invasive and an aggressive growth pattern with a marked bone resorption. In addition, the local recurrence and distant metastasis of AB also sometimes occurs, which resembles one of the typical malignant potentials. From these points of view, to understand better the mechanisms of AB cell migration or invasion is necessary for the better clinical therapy and improvements of the patients' quality of life. Microtubules in eukaryotic cells reveal the shape of hollow cylinders made up of polymerized alpha (α)- and beta (β)-tubulin dimers and form the cytoskeleton together with microfilaments and intermediate filaments. Microtubules play important roles in cell migration by undergoing assembly and disassembly with post-translational modifications. Stability of microtubules caused by their acetylation is involved in cell migration. In this study, we investigated the expression and distribution of acetylated α-tubulin and alpha-tubulin N-acetyltransferase 1 (αTAT1), an enzyme which acetylates Lys-40 in α-tubulin, in AB specimens, and analyzed how tubulin was acetylated by αTAT1 activation in a human AB cell line, AM-1. Finally, we clarified that TGF-β-activated kinase1 (TAK1) was phosphorylated by TGF-β stimulation, then, induced tubulin acetylation via αTAT1 activation, which subsequently activated the migration and invasion of AB cells.

Unicystic ameloblastoma: analysis of surgical management and recurrence risk factors

Unicystic ameloblastoma is a distinct pathological variant with varying evidence published about its behaviour and surgical management. Due to a paucity of large studies in the literature with long-term follow up, the aim of this study was to analyse its surgical management and identify clinicopathological features associated with recurrences. All histopathologically confirmed lesions diagnosed at two referral centres between 1995 and 2020 were retrospectively analysed. Demographic, clinical, radiological, and histopathological features were analysed along with surgical methods and follow-up data. Univariate regression analyses were performed to identify risk factors for recurrence. Sixty-three patients were included in the study with mean age of 26.3 years and a male to female ratio of 1:0.75. The majority of lesions occurred in the posterior mandible (57.1%) and were unilocular (88.9%). Most lesions were managed with enucleation followed by application of Carnoy's solution (ferric chloride: 1g; chloroform: 3 mL; glacial acetic acid: 1 mL; ethyl alcohol 96%: 6 mL) and burring of the peripheral bone margin which resulted in the lowest recurrences (9.1%) besides resection. Significantly associated clinicopathological features with recurrences included patients who were male, large lesions (>90 mm), presence of root resorption, cortical perforation, mural subtype, and retention of associated teeth. In conclusion, decision making in the management of unicystic ameloblastoma should be based on the clinicopathological features and not be solely based on the histopathological subtype. Enucleation followed by application of Carnoy's solution and burring of the peripheral bone margin was demonstrated to be the least invasive method with an acceptable low recurrence rate.

Recurrence Rates of Intraosseous Ameloblastoma Cases With Conservative or Aggressive Treatment: A Systematic Review and Meta-Analysis

Objective

This study aimed to systematically investigate and compare the post-treatment recurrence of intraosseous ameloblastoma in patients treated with conservative or aggressive approaches.

Methods

Systemic searches of PubMed, Medline, Cochrane Library, and Embase databases from inception to October 28, 2020, were conducted. Studies that aimed to evaluate the recurrence of intraosseous ameloblastoma by conservative and aggressive treatment approaches were included.

Results

A total of 20 studies with 942 ameloblastoma cases were included. Fourteen studies included patients with ameloblastoma who received conservative treatment, and 16 studies reported the overall recurrence rate for patients undergoing aggressive treatment. The pooled results indicated that the recurrence rate for aggressive treatment [0.12, 95% confidence interval (CI) = 0.09–0.16] was significantly lower than that for conservative treatment, with a recurrence rate of 0.30 (95% CI = 0.23–0.39). Similar results were obtained when stratifying the participants by the histological classification. When trying stratification analysis following the original included studies, multicystic ameloblastoma presented a much higher recurrence rate than solid and unicystic ameloblastomas.

Conclusion

These findings supported the hypothesis that aggressive treatment might lead to a lower recurrence rate than conservative treatment. More studies and meta-analyses following the new histological classification of ameloblastomas are needed to validate and support the findings.

Effectiveness of marsupialisation and decompression on the reduction of cystic jaw lesions: a systematic review

In this study, we aimed to systematically review and critically appraise the available literature concerning the effectiveness of marsupialisation and decompression on the reduction of cystic jaw lesions. The 'Preferred Reporting Items for Systematic Reviews and Meta-Analysis' guidelines were followed and the study protocol was registered at the 'International Prospective Register of Systematic Reviews' (CRD42019116099). Six main databases were searched: Embase, LILACS, PubMed, Scopus, The Cochrane Library, and Web of Science. Searches were complemented with three grey literature sources: Google Scholar, ProQuest, and Open Grey. Any reduction measures, compared with preoperative status or other procedures, were considered. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Tool. Thirty-one studies were included, of which five were judged with low, 24 with moderate, and two with high risk of bias. Considering surgical approach, 20 studies assessed the decompression and 11 the marsupialisation technique. Most studies considered these techniques as preliminary treatments, followed by enucleation. From 1088 lesions found, most were odontogenic keratocysts (33.8%), followed by unicystic ameloblastomas (21.0%), dentigerous cysts (20.6%), and radicular cysts (8.4%). Large lesions and younger individuals frequently presented more favourable responses to treatment and anatomical location was not associated with lesion reduction overall. The intervention duration generally ranged between one to two years. In conclusion, marsupialisation and decompression were mostly considered as preliminary treatments, followed by enucleation. Lesion reduction was generally considered insufficient for these techniques to be used as definitive therapies, although benefits concerning the diminished invasiveness of the secondary surgery were often proposed.

Developmental Odontogenic Lesions Associated with the Crown of an Impacted Tooth: A Guide to the Distinct Histologic Features Required for Classification

Odontogenic cysts are categorized as inflammatory and developmental. Of the developmental odontogenic cysts, the dentigerous cyst is the most common and by definition is attached to the cervical region of an unerupted tooth. The cyst envelops the crown forming a sac. However, there are other developmental cysts, and rarely, odontogenic tumors, that can have a similar clinical and radiographic presentation as dentigerous cyst, including odontogenic keratocyst, orthokeratinized odontogenic cyst and ameloblastoma, unicystic type. Understanding the key histologic differences of these cysts will aid the pathologist to correctly diagnose these lesions, ensuring appropriate clinical management.

Identification of circ_0089153/miR-608/EGFR p53 axis in ameloblastoma via MAPK signaling pathway

OBJECTIVES

This study investigated the role of circular RNAs (circRNAs) in the pathogenesis of ameloblastoma (AB), identifying potential novel targets for future targeted therapy.

MATERIALS AND METHODS

CircRNA and microRNA (miRNA) profiling in AB were built with microarrays. Six novel circRNAs were validated, circ-miRNA networks were delineated. Hsa-miR-608 was filtered over cross-comparison between database screening, miRNA microarray and validated. Circ-miRNA binding sponge was validated via luciferase reporter assay. Downstream mRNAs were screened. Regulation between miRNAs and mRNAs was confirmed in vitro. Gene interaction networks and circRNA-miRNA-mRNA interaction pathway enrichment analyses were established.

RESULTS

Six differentially expressed circRNAs were selected and validated. According to miRNAs and pathways predicted, six correlated miRNAs were selected, hsa-miR-608 was filtered and validated. The hsa_circ_0089153/hsa-miR-608 binding sponge was validated. Downstream gene interaction networks showed that EGFR and p53 had the strongest co-expression. In vitro transfection results confirmed the suppressive function of miR-608 and EGFR p53. Hsa_circ_0089153/hsa-miR-608/EGFR p53 interaction pathway enrichment analysis confirmed functions mainly enriched in MAPK and related signaling pathways regulating AB progression.

CONCLUSIONS

Six novel circRNAs were identified. Hsa_circ_0089153/hsa-miR-608 sponging was validated, hsa-miR-608 downregulated EGFR and p53, which might further regulate cell proliferation, differentiation, apoptosis, and cell cycle processes via the MAPK signaling pathway.

Mural Unicystic Ameloblastoma mimicking Odontogenic Cyst

Unicystic ameloblastoma is considered a less aggressive variant of ameloblastoma with clinical and radiographic features mimicking a cyst. Herein, we present a case of unicystic ameloblastoma in a 20-year-old female who was clinically and radiographically diagnosed as an odontogenic cyst. Unicystic ameloblastoma and its subtypes are reviewed with special emphasis on the mural variant. The main aim of this case report is to highlight (1) the need of including an odontogenic tumor in the differential diagnosis of the unilocular, well-circumscribed radiolucent lesion by the clinicians (2) importance of serial sectioning of the specimen to identify the mural component if any present, and (3) following resection as the mode of treatment.