Marsupialization inhibits interleukin-1α expression and epithelial cell proliferation in odontogenic keratocysts

Long-term bone remodeling after definitive decompression for jaw cysts based on a three-dimensional analysis

BACKGROUND

Decompression is an effective treatment for jaw cysts. Many studies have reported its effectiveness as a preliminary treatment followed by secondary enucleation. This study aimed to explore long-term bone remodeling after definitive decompression for jaw cysts based on a three-dimensional (3D) analysis.

METHODS

This was a retrospective study. The clinical and radiological data of patients with jaw cysts who underwent decompression and were followed up for two years or more at Peking Union Medical College Hospital between January 2015 and December 2020 were reviewed. The 3D radiological data before and after decompression were analyzed to study the long-term reduction in cysts, especially after one year of decompression.

RESULTS

A total of 17 patients with jaw cysts were included in this study. The radiological data showed a mean reduction rate of 78% one year after decompression. At the final examination, which was 36.1 months after decompression on average, the mean reduction rate was 86%. The unossified lesions could still ossify slowly after one year of decompression. The recurrence rate was 5.9% (1/17).

CONCLUSIONS

Bone remodeling continued for a long time after decompression. Definitive decompression could be an option for most patients with jaw cysts. Long-term follow-up is required.

Model-assisted marsupialization of a large odontogenic keratocyst in the maxillofacial region using a multicolored 3D-printed model: A novel approach in surgical planning and teaching

3D printing can improve surgical planning and coordination between the healthcare team and serve as a valuable educational tool for students.

Abstract

Although the occurrence of odontogenic keratocysts (OKCs) in the maxillofacial region is not uncommon, their aggressive growth behavior requires advanced surgical techniques for minimal recurrence. The current case report describes the use of a multicolored 3D-printed model as an interactive visual aid for the surgical planning and management of an OKC treated with a minimally invasive surgical decompression technique. A cone-beam computed tomography scan of the patient showed a profound OKC involving the left side of the body of the mandible. A 3D printer was used to print a multicolor resin model of the patient's OKC lesion within the mandible. The printed model was successfully used as a planning tool for surgical intervention (i.e., marsupialization and enucleation) of the OKC. The model was also used as a handheld interactive visual aid for dental students, so they could more effectively understand the anatomical and surgical complexity of the case. The novel use of the multicolor 3D-printed model for treatment of this OKC improved visualization of the lesion during surgical planning and was a valuable teaching tool for educational discussion of this case.

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.

Use of Marsupialisation for a Conservative Approach to Huge Cystic Lesions of the Jaws - A Report of three Cases

Rationale

The management of cystic lesions of the jaws presents a challenge to the surgeon. Marsupialisation, one of the conservative management options, has been used as a single or combined surgical treatment modality for the cystic lesions of the jaws.

Patient Concerns

All patients presented with a complaint of a firm swelling of the face with one of the patients presenting with paraesthesia in the affected area.

Diagnosis

Clinical and radiographic examination was carried out followed by aspiration cytology. All lesions were provisionally diagnosed with odontogenic cystic lesions.

Treatment

Marsupialisation under general anaesthesia was carried out for all patients. Postoperatively, a customised obturator was fabricated.

Outcomes

All the patients showed good radiological ossification postoperatively.

Take-Away Lessons

The approach to larger cysts remains controversial. The long-term results following the marsupialisation of extensive cysts of this report may help surgeons to opt for a conservative approach to such lesions before aggressive options.

Minimally Invasive Two-Staged Surgery in the Treatment of Large Cystic Lesions of the Jaw

Background: Cystic lesions of the jaw are commonly found in clinical practice. Large, expansive cysts raise challenges for the clinician from both diagnostic and surgical perspectives. The aim of our work is to present a combined, two-staged surgical approach in histologically confirmed non-aggressive cystic lesions of the jaw. Methods and Results: We report the case of an extensive mandibular cyst, associating a high risk of bone fracture, that is treated in the initial stage by cystic decompression through marsupialization with concomitant histological diagnostic confirmation, followed in the second stage by radical excision and mandibular reconstruction with titanium mesh, with the purpose of prevention for oro-cystic chronic fistula formation. Conclusions: Large odontogenic mandibular cysts imply a meticulously conducted assessment and treatment. Marsupialization should be taken into consideration for the treatment of large cystic lesions, followed by secondary enucleation, with minimal risks for the patient. The soft tissue healing process can be optimized with the use of titanium meshes, as an alternative for other reconstructive techniques, in the management of large cystic lesions.

Does active decompression of odontogenic keratocyst change the histologic diagnosis?

AIM

The purpose of this study was to compare the histopathologic findings of pre- and post-active decompression of odontogenic keratocyst and to establish if such findings were consistent.

MATERIALS AND METHODS

A retrospective case series from a group of patients diagnosed with odontogenic keratocyst who underwent active decompression and distraction sugosteogenesis followed by final enucleation was designed and implemented. The dependent variable was changed in histologic diagnosis, as evaluated by an oral and maxillofacial pathologist. Other variables included age, gender, anatomic location of the lesion, and time elapsed from initial biopsy to final enucleation.

RESULTS

Six patients diagnosed with odontogenic keratocyst who underwent active decompression followed by enucleation and curettage were studied. The mean age was 45.6 years (range, 16 to 74) 83.33% were males, 16.66 females. Lesions were located in the mandible in 83.33% of cases and in the maxilla in 16.66% of cases. Post-active decompression histologic examination at the time of definitive enucleation was consistent with the initial diagnosis in 83.33% of cases.

CONCLUSIONS

The histopathological diagnosis at the time of definitive treatment by enucleation and curettage is consistent with the pre-active decompression diagnosis.

Decompression strategy for critical-sized lesions: A case series and literature review

Critical-sized lesions are defined as the smallest sized intraosseous wound in a particular bone that will not heal spontaneously during the lifetime of that animal. These critical-sized entities pose a unique challenge in endodontics, where these lesions are most likely cystic, with dimensions extending over 10 mm. This paper describes a structured methodology to treat such cases whilst also highlighting inconsistencies and variability between practitioners regarding management of critical-sized lesions. The case series demonstrates that non-surgical root canal therapy followed by surgical decompression may be the treatment of choice for such pathosis. A 16 gauge nasogastric tube was used as a decompression device and sutured to surrounding mucosa. Healing was evaluated using both two- and three-dimensional radiographs. Decompression of critical-sized lesions would appear to be a reliable, conservative and an altogether complete procedure that may not warrant second-stage surgery.

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.

Gorlin-Goltz syndrome with familial manifestation

AIMS

The detection of odontogenic keratocysts (OKC) in the oral cavity is one of the main criteria for the clinical manifestation of Gorlin-Goltz syndrome (Nevoid Basal Cell Carcinoma Syndrome - NBCCS). From a clinical point of view, we distinguish between "syndromic" and "sporadic" OKC. Syndromic cysts, often multifocal, may be an accidental finding on X-ray examination. They can manifest gradually depending on the development of permanent dentition. Sporadic cysts are rather solitary lesions with clinical manifestation in adulthood.

METHODS

Mutations in the PTCH1 gene are thought to be the cause of the clinical manifestation of NBCCS. These abnormalities can be transmitted from one generation to another and lead to a familial occurrence of the disease. In 35-50% of cases, these are a newly arising mutations. It is necessary to take into account the typical manifestations which in the next generation begin at a younger age and the disease usually has a more serious course.

RESULTS

We found a familial manifestation of NBCCS in two pairs of patients (mother and daughter and two siblings). Odontogenic keratocysts and cutaneous basal cell carcinomas were diagnosed and genetic testing revealed mutations in the PTCH 1 gene in all four individuals.

CONCLUSIONS

With regard to the possibility of familial occurrence of NBCCS, it is necessary to pay increased attention to family history and, if necessary, to ensure clinical and genetic examination of parents and other family members. Patients of childbearing potential with evidence of NBCCS should be informed of the increased likelihood of the disease in the offspring.

Changes in Cellular Regulatory Factors before and after Decompression of Odontogenic Keratocysts

Decompression followed by enucleation, which is one of the treatments used for odontogenic keratocysts (OKCs), is frequently used in OKC lesions of large sizes. This method offers the advantage of minimizing the possibility of sensory impairment without creating a wide-range bone defect; moreover, the recurrence rate can be significantly lower than following simple enucleation. This study aimed to assess the changes in histology and expression of proliferation markers in OKCs before and after decompression treatment. A total of 38 OKC tissue samples from 19 patients who had undergone decompression therapy were examined morphologically and immunohistochemically to observe changes in proliferative activity before and after decompression. The markers used for immunohistochemistry (IHC) staining were Bcl-2, epidermal growth factor receptor (EGFR), Ki-67, P53, PCNA, and SMO. The immunohistochemistry positivity of the 6 markers was scored by using software ImageJ, version 1.49, by quantifying the intensity and internal density of IHC-stained epithelium. The values of Bcl-2, Ki-67, P53, proliferating cell nuclear antigen (PCNA), and SMO in OKCs before and after decompression showed no significant change. No correlation between clinical shrinkage and morphologic changes or expression of proliferation and growth markers could be found. There was no statistical evidence that decompression treatment reduces potentially aggressive behavior of OKC within the epithelial cyst lining itself. This might indicate that decompression does not change the biological behavior of the epithelial cyst lining or the recurrence rate.

Therapeutic management of the odontogenic keratocyst. An energetic approach with a conservative perspective and review of the current therapeutic options

Background

Odontogenic keratocysts (OKC) are cystic lesions appearing in the jaws, usually asymptomatic with a progressive growth into the bone. Many of them are diagnosed by a routine radiological examination.

Material and Methods

This study reports a 12-year-old girl that presented an asymptomatic large radiolucent unilocular lesion associated to the crown of 3.8 that caused displacement of the molar and the inferior alveolar canal. Differential diagnosis included OKC, unicystic ameloblastoma, ameloblastic fibroma, dentigerous cyst and orthokeratinized odontogenic cyst. Two surgical interventions were performed; first, a marsupialization, and 10 months after, the third molar extraction plus cyst enucleation, mucosa excision and the application of Carnoy’s solution.

Results

The anatomopathological exam confirmed diagnosis of OKC. There was no evidence of recurrence after 2 years of follow-up.

Conclusions

Marsupialization followed by surgical enucleation with mucosa excision and Carnoy’s solution can help manage treatment of OKC, a lesion characterized by an aggressive behavior.

Key words:Odontogenic keratocyst, mucosa excision, carnoy solution, third molar, tooth extraction.

Analysis of Marsupialization of Mandibular Cysts in Improving the Healing of Related Bone Defects

PURPOSE

Marsupialization, designed to reduce the mandibular cyst volume, has continued to debated regarding its influence on the healing of the related bone cavity. The aim of the present study was to evaluate the 3-dimensional radiographic variation over time in mandibular odontogenic cystic lesions after marsupialization and assess the correlations between these variations and variables that can affect the procedure.

MATERIALS AND METHODS

We planned a retrospective cohort study. The predictor variables were the treatment duration, preoperative volume, patient age, histologic type, and number of preoperative residual bony walls. The outcomes variables were the postoperative volume reduction and the daily reduction rate calculated using computed tomography (CT) from before to after marsupialization using software designed for volumetric reconstruction and measurement of cyst-related bone defects. The descriptive and bivariate statistics were computerized, and the significance level was set at P = .05.

RESULTS

The sample included 15 patients (12 men and 3 women; mean age, 51.6; range, 27 to 85 years) affected by keratocysts (n = 6), dentigerous cysts (n = 6), and radicular cysts (n = 3) who had undergone marsupialization. The median duration of marsupialization was 406 days (25th to 75th percentile, 276 to 519). The mean ± standard deviation (SD) pre- and postdecompression volumes were 6,908.27 ± 2,669.058 and 2,468.13 ± 1,343.517 mm³, respectively (P < 0.001), and the mean ± SD percentage of reduction was 63.90 ± 13.12%. The volume decrease in the bone defects correlated positively with the treatment duration (P = .009) and preoperative volume (P < .001). However, no correlation was found with the other variables (P > .05) nor between the daily reduction rate and other variables (P > .05).

CONCLUSIONS

Marsupialization appears useful in improving the healing of cyst-related bone defects in mandibles, especially larger defects. Further studies with a wider sample size would add more knowledge to this topic.

Management of an extensive odontogenic keratocyst: A rare case report with 10-year follow-up

INTRODUCTION

The odontogenic keratocyst (OKC), previously known as keratocystic odontogenic tumor has been the most disputable pathologies of the maxillofacial region. Patients with OKC are often asymptomatic but may present with pain, swelling, or discharge. Despite the aggressive nature, previous literature as early as 1970s reported the fact that parakeratinized OKC can be treated by means of marsupialization alone.

PATIENTS CONCERNS

The patient had reported with a complaint of pain and swelling in relation with a tooth in mandibular right quadrant.

DIAGNOSIS

This case report discusses features of a rare, extensive, panmandibular OKC that is only second of its kind mentioned in the literature.

INTERVENTION

As a usual treatment protocol, marsupialization was attempted first. Immunohistochemical analysis revealed reduced expression of Ki-67 and B cell lymphoma 2 (bcl-2) markers after marsupialization from 2 separate sites. However, due to incomplete resolution in the lower right anterior region, an aggressive approach was taken by curetting it out surgically along with associated teeth and cortical plate followed by application of Carnoy's solution.

OUTCOME

Postsurgery uneventful healing of the lesion was noted on regular follow-up visits with complete resolution at 40 months. The case has been followed for 10 years with no sign of relapse and reoccurrence.

CONCLUSIONS

Based on the expression of markers it can thus be concluded that Ki-67 and bcl-2 are site specific and bear strong relationship with the recurrence of OKCs.

Cysts and tumors of the jaws treated by marsupialization: A description of 4 clinical cases

Since the 4th edition of the World Health Organization’s Classification of Head and Neck Tumours was published in January of 2017, the keratocystic odontogenic tumor is back into the cyst category as odontogenic keratocyst (OKC). Depending on the size of the cyst, its location and the patients’ age, several treatment options are available: curettage, enucleation, radical treatment and marsupialization. The marsupialization is a conservative technique used in early tumor stages, as curative treatment for the odontogenic cyst. Despite its disadvantages and controversies, the marsupialization remains an interesting therapeutic choice in the case of large cysts, or in very young or old patients. We describe, in this article, four clinical cases of odontogenic cysts. We report the surgical management and the subsequent evolution of the patients. The discussion focuses on the indications, advantages and limitations of the odontogenic cyst’s marsupialization. We review the specific conditions of the odontogenic cysts that could make the marsupialization the optimal therapeutic option. In our cases, the marsupialization proved to be a conservative technique which allowed the respect of neighboring anatomical structures, particularly in the case of large cysts, but requires prolonged clinical and radiological monitoring. Pathological entity for our cases was different. Thus, the treatment outcome may be different too. This series is very small and the reader should be cautious about drawing broad conclusions regarding the optimal therapeutic choice.

Key words:Marsupialization, odontogenic cyst.

Treatment of Multiple Odontogenic Keratocysts Involving Chinese Patients

PURPOSE

The optimal treatment of odontogenic keratocysts (OKCs) remains a matter of debate in reported studies. The present study aimed to estimate the postoperative recurrence rates of multiple OKCs (MOKCs) in Chinese patients.

MATERIALS AND METHODS

A retrospective cohort study of histologically confirmed MOKCs treated from 2003 to 2017 using enucleation, marsupialization alone, enucleation and peripheral ostectomy, or marsupialization followed by secondary enucleation was performed. Patients with MOKCs who had undergone follow-up for 12 or more months with panoramic radiographs and radiographs of the chest and skull available from the first visit and had been treated by the same team using the same treatment protocol were included in the study. Patients were excluded if the lesion had been treated previously, they had a solitary OKC, or their medical records were not available for review. The treatment methods, recurrence rate, and interval to recurrence were evaluated. The Kaplan-Meier method was used to estimate the survival rate and median time to recurrence. Univariate analysis was used to identify the risk factors associated with recurrence. Significant differences were determined at an α level of 5%.

RESULTS

The sample included 81 patients with MOKCs; 21 (25.6%) were male and 60 (74.07%) were female. The age range was 7 to 63 years (mean ± standard deviation, 18.4 ± 4). The overall recurrence rate was 26.63%, with an overall recurrence-free interval of 26.85 months. The average length of follow-up was 55.68 months. No association was found between the treatment method used and the risk of recurrence (P = .178). Although the interval to recurrence was not affected by any of the study variables, the average interval to the recurrence of MOKCs involving the maxilla was short compared with that of MOKCs involving the mandible.

CONCLUSIONS

The surgical treatment method did not influence the risk of recurrence in patients with MOKCs, and the interval to recurrence was not associated with any of the study variables.

Distraction Sugosteogenesis: Its Biologic Bases and Therapeutic Principles

PURPOSE

Recently, the terms sugosteogenesis and distraction sugosteogenesis have been introduced to the scientific literature. While the former describes a biologic phenomenon, the latter refers to the clinical technique which relies on the accelerated normal bone healing process that takes place at the osseous walls surrounding a cystic cavity when active negative pressure is applied. The purpose of this study is to provide the biologic bases and the therapeutic principles of this emerging technique. Employing well-stablished biologic principles, clinical evidence from analogous techniques, emerging experimental data, and circumstantial evidence, this study presents the possible mechanism of action of the evacuator for odontogenic cysts (Evocyst), a closed, vacuum-like drain system intended to treat cystic conditions using negative pressure.

METHODS

A review of the literature was done. Keywords for the Medline search were: marsupialization, decompression, odontogenic cysts, effects of negative pressure on bone, and negative pressure wound therapy. In addition, relevant publications from the reference list of the retrieved studies were considered. The matches were evaluated for relevance and analyzed accordingly. Clinical reports used to illustrate the concept of distraction sugosteogenesis were performed following the Declaration of Helsinki on medical protocol and ethics.

RESULTS

Currently, the standard of care to manage odontogenic cystic lesions includes marsupialization, enucleation and curettage, decompression, and surgical resection. However, there is a need for an alternative option in which the entity could be treated while promoting bone formation. With large odontogenic cystic conditions treated in a short period of time, distraction sugosteogenesis appears to be a choice.

CONCLUSION

The application of negative pressure to osseous cells produces a stretching that creates mechanical cues that trigger signaling pathways, promotes fluid flow, and enhances angiogenesis. All of them, combined, may explain sugosteogenesis. The clinical application of such parameters may explain the good clinical results obtained with the Evocyst.

Increased level of cell-derived microparticles in the cyst fluids of odontogenic keratocysts

The aim of this study was to examine the level and basic characteristics of cell-derived microparticles (MPs) in the cyst fluids of odontogenic keratocysts (OKCs). For this purpose, MPs from the cyst fluids (CFMPs) of OKCs were purified by a classic differential centrifugation method and characterized by a transmission electron microscope and fluorescence microscope. Flow cytometric analysis was used to determine the size, concentration and cellular origins of the CFMPs. Moreover, the expression level of receptor activator for nuclear factor-κB ligand in the OKCs was evaluated by immunohistochemical staining and then analyzed for its correlation with the concentration of CFMPs by Spearman's rank correlation test. In addition, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and tartaric-resistant acid phosphatase (TRAP) staining were performed to examine the osteoclastogenesis of mouse bone marrow-derived macrophages (BMMs) in response to CFMPs. The results revealed that the levels of total CFMPs were significantly elevated in OKCs compared with dentigerous cysts (DCs) and radicular cysts (RCs). In addition, in vitro experiments further revealed that CFMPs derived from the OKCs of patients could be taken up by BMMs, leading to a significant increase in the mRNA expression levels of nuclear factor of activated T-cells 1 (NFATc1) and TRAP. Moreover, TRAP-positive multinucleated osteoclasts were successfully cultured in the presence of macrophage colony-stimulating factor (M-CSF) and CFMPs with BMMs. On the whole, our findings indicate that patients with OKCs have higher levels of CFMPs compared with patients with DCs and RCs, which may be associated with the bone resorption of OKCs.

Expression of TP53 and IL-1α in unicystic ameloblastoma predicts the efficacy of marsupialization treatment

In this study, we evaluated the effects of marsupialization in treating unicystic ameloblastoma (UA) and investigated the relationship between TP53 and interleukin 1 α (IL-1α) expression and the clinical outcome of UA treated with marsupialization.Consecutive patients treated with marsupialization and curettage at Shanghai Ninth People's Hospital were included. According to the unified standard, 48 patients were included in this study. Of these, 20 showed a good response, 10 a partial response, and 18 no response, based on the outcome of the marsupialization procedure. The expression of proteins TP53 and IL-1α was detected with immunohistochemistry (IHC). The clinical and pathological characteristics of the patients were analyzed.Analysis of the clinical and pathological characteristics showed that the effects of marsupialization treatment were significantly associated with lesion location (P < .001) and tumor diameter (P = .01). IHC showed that TP53 expression was significantly higher in the good-response group than in the partial- or no-response group (P = .02), and IL-1α expression was significantly higher in the good-response group than in the partial- and no-response groups (P = .03).Marsupialization is an effective preliminary procedure for treating UA before curettage and peripheral ostectomy. The expression of the TP53 and IL-1α proteins correlates directly with the outcome of UA treated with marsupialization.

Comparison of the osteogenic differentiation of orofacial bone marrow stromal cells prior to and following marsupialization in patients with odontogenic cyst

Decompression has been considered a valuable tool for odontogenic cystic lesions to minimize cyst size with low morbidity and recurrence. However, whether decompression has a role in regulating stem cell properties of orofacial bone marrow stromal cells (BMSCs) around the cysts has not been fully investigated. The present study compared the stem cell marker profile and osteogenic differentiation potential of orofacial BMSCs prior to and following marsupialization (pre-BMSCs vs. post-BMSCs) in the same individuals. The results demonstrated that post-BMSCs proliferated significantly faster, displayed higher colony-forming unit-fibroblast capacity and demonstrated higher expression of octamer binding protein 4, Nanog and SRY-related HMG box 2 when compared with the pre-BMSCs. Notably, the osteogenic potential was greater in the post-BMSCs compared with in pre-BMSCs, by demonstrating that the protein and mRNA expression levels of osteopontin, runt-related transcription factor 2, osteocalcin, alkaline phosphatase and osterix were upregulated in pre-BMSCs. Furthermore, the phosphorylated levels of extracellular signal-regulated kinase and c-Jun N-terminal kinase were enhanced in post-BMSCs. In conclusion, the study indicated that decompression influences the stem cell properties of orofacial BMSCs, and further studies are needed to verify the findings.

The Inflammatory Radicular Cysts Have Higher Concentration of TNF-α in Comparison to Odontogenic Keratocysts (Odontogenic Tumour)

TNF-α is a pleiotropic cytokine that is considered as a primary modifier of inflammatory and immune reaction in response to various inflammatory diseases and tumour. We investigated levels of TNF-α in 43 radicular cysts and 15 odontogenic keratocysts, obtained from patients undergoing surgery, under local anaesthesia, and after aspiration of cystic fluid from non-ruptured cysts. TNF-α is elevated in both cysts’ fluid, but higher values were found in radicular cysts in comparison to keratocysts. The significantly higher concentration of TNF-α was associated with smaller radicular cysts, higher protein concentration, higher presence of inflammatory cells in peri cystic tissues, and the degree of vascularisation and cysts wall thickness (Mann-Whitney U-test, p<0.05). No correlation was found based on these parameters in odontogenic keratocyst, but all cysts have detectable concentrations of TNF-α. We here for the first time present that a difference in the concentration of TNF-α exists between these two cystic types.

The anecdote of viral etiopathogenia in ameloblastoma and odontogenic keratocyst: Why don't we let it go?

BACKGROUND

Ameloblastoma (AM) and odontogenic Keratocyst (OKC) are destructive odontogenic lesions of the gnathion. Although their exact pathogeneses are not yet totally understood, the viral etiopathogenesis in AM and KCOT has been proposed. True to syndromic keratocystic odontogenic tumor (sKCOT) and non-syndromic OKC is the high recurrence rate.

OBJECTIVES

Given that shared pathways trailed by AM and by sKCOT/OKC have been suggested, this study, however, contrasts the expression of AM and OKC for viral antibodies.

METHOD

A total of archival 80 paraffin blocks of cases of parakeratinized odontogenic keratocyst (non-syndromic KCOTs) and of ameloblastomas (n = 40 for each) were included in this study to be sectioned and stained for two immunohistochemical markers: anti-human papillomavirus and Epstein-Barr virus-encoded latent membrane protein.

RESULTS

All the submitted cases of AM and parakeratinized OKC were negative for both markers: anti-HPV and anti-LMP-1.

CONCLUSIONS

Although results could have been biased, given the same ethnic group and territory examined in this study, all cases were negative for both markers. Therefore, the viral contribution to the etiopathogenesis in AM and OKC could not be established in this study.

Decompression of keratocystic odontogenic tumors leading to increased fibrosis, but without any change in epithelial proliferation

OBJECTIVE

The aim of this study was to investigate whether decompression treatment induces changes in the histology or biologic behavior of keratocystic odontogenic tumor (KCOT).

STUDY DESIGN

Seventeen patients with KCOT underwent decompression treatment with or without enucleation. Histologic evaluation and immunohistochemical expression of p53, Ki-67, and Bcl-2 were analyzed by using conventional microscopy.

RESULTS

KCOT showed significantly increased fibrosis (P = .01) and a subjective reduction in mitotic activity (P = .03) after decompression. There were no statistically significant changes in the expression of proliferation markers. An increase in daughter-cysts or epithelial rests was seen after decompression (P = .04). Recurrence was noted in four of 16 cases, and expression of p53 was strongly correlated with prolonged duration of treatment (P = .01) and intense inflammatory changes (P = .02).

CONCLUSIONS

Structural changes in the KCOT epithelium or capsule following decompression facilitate surgical removal of the tumor. There was no statistical evidence that decompression influences expression of proliferation markers in the lining, indicating that the potential for recurrence may not be restricted to the cellular level. The statistically significant increase of p53 expression with increased duration of treatment and increase of inflammation may also indicate the possibility of higher rates of recurrence with prolonged treatment and significant inflammatory changes.

Signaling Pathways Regulating IL-1α-induced COX-2 Expression

Interleukin-1α(IL-1α) stimulates the production of prostaglandin E2 (PGE2) in odontogenic keratocyst fibroblasts. However, the signaling pathways remain obscure. In this study, we investigated IL-1αsignaling pathways that regulate cyclooxygenase-2 (COX-2) expression in odontogenic keratocyst fibroblasts. IL-1αincreased the expression of COX-2 mRNA and protein, and PGE2 secretion in the fibroblasts. IL-1αincreased the phosphorylation of extracellular signal-regulated protein kinase-1/2 (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK). PD-98059, SB-203580, SP-600125, and PDTC—which are inhibitors of ERK1/2, p38, JNK, and nuclear factor-κB (NF-κB), respectively—attenuated the IL-1α-induced COX-2 mRNA expression and activated protein kinase C PGE2 secretion. IL-1α(PKC), and PKC inhibitor staurosporine inhibited IL-1α-induced phosphorylation of ERK1/2, p38, and JNK, and decreased IL-1α-induced COX-2 mRNA expression. Thus, in odontogenic keratocyst fibroblasts, IL-1αmay stimulate COX-2 expression both through the PKC-dependent activation of ERK1/2, p38, and JNK signaling pathways, and through the NF-κB cascade.

Effects of Positive Pressure in Odontogenic Keratocysts

Intracystic fluid pressure is thought to be involved in odontogenic cyst growth. In this study, we investigated the effects of positive pressure on the expression of interleukin-1α (IL-1α), matrix metalloproteinases (MMPs), and prostaglandin E2 (PGE2) in odontogenic keratocysts to determine whether this pressure stimulates inflammatory cytokine production and signaling of osteoclastogenic events. Positive pressure enhanced the expression of IL-1α mRNA and protein in odontogenic keratocyst epithelial cells, and increased the secretion of MMP-1, MMP-2, MMP-3, and PGE2 in a co-culture of odontogenic keratocyst fibroblasts and the epithelial cells. The pressure-induced secretions were inhibited by an interleukin-1 receptor antagonist. Recombinant human interleukin-1α (rhIL-1α) increased the secretion of MMP-1, MMP-2, MMP-3, and PGE2 in the fibroblasts. Furthermore, in the fibroblasts, rhIL-1α enhanced the expression of macrophage colony-stimulating factor (M-CSF) mRNA, and rhIL-1α-induced PGE2 increased the expression of nuclear factor κB ligand (RANKL) mRNA. Thus, positive pressure may play a crucial role in odontogenic keratocyst growth via stimulating the expression of IL-1α in epithelial cells.

Treatment of Keratocystic Odontogenic Tumours: A Prospective Study of 30 Cases

AIM

This prospective study aimed at presenting different treatment modalities and its association with the recurrence rate of KCOT.

MATERIAL AND METHOD

The study was conducted on 30 patients diagnosed with KCOT between March 2009 and 2012. The patients were followed up for a period of at least 1 year. The clinical, radiographic and demographic data were recorded and four different treatment modalities were followed to assess the recurrence of the tumour.

RESULTS

In the study, KCOT showed male predominance with a male: female ratio of 23:7. Of the total cases, 26 (86.67 %) patients had parakeratinised KCOT and the rest 4 (13.3 %) patients had orthokeratnised KCOT. Nine (30 %) patients were reported with recurrence of the tumour within 1-2 years of surgery-all these patients had parakeratinised cyst. Recurrence was observed in four (50 %) out of eight cases of marsupialisation and four (44.44 %) out of nine cases of treatment using the enucleation process. No recurrence was seen in patients treated with resection; however only one out of three patients treated with enucleation, followed by fixation with Carnoy's solution showed signs of recurrence. The histopathological examination determined the aggressive nature of KCOT and its association with the recurrence rate as well. The findings of our study indicate that more aggressive treatment can aid in reducing the chances of recurrence.

Immunoexpression of tumour necrosis factor-α, interleukin-1α and interleukin-10 on odontogenic cysts and tumours

AIM

To analyse the immunoreactivity of IL-1α, TNF-α and IL-10 in odontogenic cysts and tumours and to investigate possible associations with established biological behaviours of these different lesions.

METHODOLOGY

Immunohistochemical expression of anti-IL-1α, anti-TNF-α and anti-IL-10 antibodies was assessed on epithelium and mesenchyme of 20 radicular cysts (RCs), 20 residual cysts (RECs), 20 dentigerous cysts (DCs), 18 solid ameloblastomas (SAs), 20 keratocystic odontogenic tumours (KCOTs) and 15 dental follicles (DFs). Comparative analysis of data was performed using the nonparametric Wilcoxon signed-rank test and Kruskal-Wallis's test.

RESULTS

Significantly greater expression of IL-1α in the epithelium was noted in RC, KCOT and SA (P = 0.01), whilst IL-10 and TNF-α was in the epithelium of RC, DC and KCOT (P < 0.01). In the mesenchyme, significantly greater immunopositivity was observed for IL-1α, IL-10 and TNF-α in KCOT, DC and RC (P < 0.01). In epithelial and mesenchymal tissues, there were a significant number of cases of RC and DC with IL-1α < IL-10 ratio (P < 0.01), whilst SA and KCOT showed IL-1α > IL-10 (P < 0.01). There was a significantly greater percentage of DF, DC and KCOT with TNF-α > IL10 ratio (P < 0.01).

CONCLUSION

These results suggest involvement of the proteins in the pathogenesis of odontogenic cysts and tumours, with emphasis on the highest immunoreactivity of osteolysis stimulating factors in tumours with aggressive biological behaviour, such as SA and KCOT.

Differential expression of inducible nitric oxide synthase in keratocystic odontogenic tumors prior and subsequent to decompression

The aim of the present study was to investigate the expression of inducible nitric oxide synthase (iNOS) in keratocystic odontogenic tumors (KCOTs) prior and subsequent to decompression and to explore the association between iNOS expression and changes in clinical features. Sixteen pairs of specimens obtained at the time of decompression and subsequent curettages were collected and immunohistochemically examined using an antibody against iNOS. The intensity of iNOS staining was evaluated semi-quantitatively for statistical analysis. Prior to decompression, 87.5% of KCOT samples showed no immunohistochemical reactivity for iNOS. Only 12.5% of samples exhibited slight staining for iNOS in the cytoplasm of cells in the epithelial layer. Subsequent to decompression, all the samples exhibited moderate to intense staining for iNOS in the cytoplasm and membrane of cells in the epithelial and fibrous layers. This increased expression of iNOS following decompression was statistically significant (P<0.01). The results demonstrated distinct expression of iNOS in KCOT samples prior and subsequent to decompression, indicating that iNOS may have a role in mediating changes in clinical features.

Decompression of Odontogenic Cystic Lesions: Past, Present, and Future

Tumors and cystic lesions of the jawbones have been described since the late 1600s and it took another 200 years for classification systems to appear in the medical, surgical, and dental literatures. In the late 1800s, Carl Partsch introduced cystostomy, a method by which the cyst is converted into a pouch by suturing its lining to the mucosa of the oral cavity. The purpose of this article is to analyze the history, present, and future of cystic conditions of the jaws and decompression, a modality of treatment that during the past few years has regained the attention of oral and maxillofacial surgeons and pathologists owing to its relative simplicity and effectiveness compared with other conservative options.

Keratocystic Odontogenic Tumours: Etiology, Pathogenesis and Treatment Revisited

INTRODUCTION

Among the pathological entities that affect the maxillofacial region, Keratocystic odontogenic tumour has been subject to a lot of debates, controversies and speculations because of its diverse nature and high recurrence rates.

MATERIALS AND METHODS

The authors conducted a search in English literature using the following keywords; "Odontogenic keratocyst" and "Keratocystic odontogenic tumour". The aim of the paper was to review all aspects of the entity, including etiology, pathogenesis, clinical and radiological manifestations, growth potential, recurrence and treatment modalities.

CONCLUSION

The controversial nature of the pathology not withstanding, there is in general a broad consensus on treating the entity conservatively with emphasis on a long term review.

Regeneration of a Compromized Masticatory Unit in a Large Mandibular Defect Caused by a Huge Solitary Bone Cyst: A Case Report and Review of the Regenerative Literature

The reconstructive options for large expansive cystic lesion affecting the jaws are many. The first stage of treatment may involve enucleation or marsupialization of the cyst. Attempted reconstruction of large osseous defects arising from the destruction of local tissue can present formidable challenges. The literature reports the use of bone grafts, free tissue transfer, bone morphogenic protein and reconstruction plates to assist in the healing and rehabilitation process. The management of huge mandibular cysts needs to take into account the preservation of existing intact structures, removal of the pathology and the reconstructive objectives which focus both on aesthetic and functional rehabilitation. The planning and execution of such treatment requires not only the compliance of the patient and family but also their assent as customers with a voice in determining their surgical destiny. The authors would like to report a unique case of a huge solitary bone cyst that had reduced the ramus, angle and part of the body of one side of the mandible to a pencil-thin-like strut of bone. A combination of decompression through marsupialization, serial packing, and the fabrication of a custom made obturator facilitated the regeneration of the myo-osseous components of the masticatory unit of this patient. Serial CT scans showed evidence of concurrent periosteal and endosteal bone formation and, quite elegantly, the regeneration of the first branchial arch components of the right myo-osseous masticatory complex. The microenvironmental factors that may have favored regeneration of these complex structures are discussed.

Bilateral odontogenic keratocyst of the mandible

Odontogenic keratocyst (OKC) is a cyst of dental origin with an aggressive clinical behavior, having high recurrence rate. Multiple cysts are associated with bifid-rib basal cell nevus syndrome (Gorlin syndrome). We present a case of bilateral odontogenic keratocyst in a cleft lip patient.

Altered expression of podoplanin in keratocystic odontogenic tumours following decompression

Marsupialisation or decompression is frequently performed as a conservative therapy for keratocystic odontogenic tumours (KCOTs). Positive podoplanin (PDPN) expression in the epithelium of KCOT has been previously reported and may be associated with neoplastic invasion. In the present study, changes in PDPN expression were observed in the epithelium of KCOTs following decompression. In total, 16 pairs of paraffin-embedded tissue specimens obtained at the time of decompression and at two-stage curettage or enucleation were collected and immunohistochemically examined using an antibody against PDPN. The intensity of PDPN staining was evaluated with a semi-quantitative detection method and statistically analysed. The immunohistochemical reactivity of PDPN was consistently markedly positive in 93.8% of KCOT samples prior to decompression. The positive staining was immunolocalised to the cell membrane and cytoplasm of cells in the basal layer and extended into the suprabasal layer for two to three cell layers. At the time of curettage, 2 of the 16 (12.5%) cases were completely negative, 11 of the 16 (68.8%) cases were locally positive and 3 of the 16 (18.7%) cases showed a ‘linear staining’ pattern, as the PDPN-positive cells were restricted to within the single basal layer. The expression level of PDPN was significantly decreased (P<0.05) and a significant loss or reduction of PDPN expression was observed in KCOTs following decompression. Larger sample groups are required to further verify this result.

R, Roa K. UD, Joshua E, Ahmed AS, Chittamsetty H. Immunohistochemical Expression of PCNA in Epithelial Linings of Selected Odontogenic Lesions

AIM

Though odontogenic lesions have in common origin from the primitive odontogenic epithelium , there is a diversity in their initiation behavior and growth. The aggressive nature of odontogenic keratocyst similar to ameloblastoma in comparision with the other common odontogenic (dentigerous and radicular) cyst could be due to possible differences in their epithelial linings. PCNA (Proliferating cell nuclear antigen) is a cell cycle related antigen, used in the study of cell kinetics of these epithelial linings, to corelate the biological behaviour among these common odontogenic lesions.

OBJECTIVES

This paper has intended to study the cell kinetics of 4 selected odontogenic lesions (dentigerous cyst, radicular cyst,odontogenic keratocyst and ameloblastoma) to demonstrate differences in their epithelial linings.

MATERIAL AND METHODS

Sixty samples of paraffin embedded tissue specimens (archival tissues) were included (15 radicularcysts, 15 odontogenic keratocysts; 15 dentigerous cysts and15 Ameloblastoma.

RESULTS

Among cyst OKC had higher values than DC and RC. When staining results of all the cyst were compared individually with ameloblastoma ,the staining results of OKC was similar to ameloblastoma ,and ameloblastoma presented higher values than OKC (p=0.000).

CONCLUSION

The results of this study show 1) Though OKC and DC are developmental in origin and radicular cyst is inflammatory, OKC has intrinsic growth potential among these cyst 2). Ameloblastoma has similar proliferative potential as OKC and hence it has been reinforced as KCOT(Keratocystic odontogenic tumour) in the recent classification.

Decompression as a treatment for odontogenic cystic lesions of the jaw

PURPOSE

To evaluate the effectiveness of decompression as the primary treatment of odontogenic cystic lesions of the jaw involving factors that affect relative shrinking speed and bone regeneration.

PATIENTS AND METHODS

A total of 32 patients with odontogenic cystic lesions of the jaw underwent decompression with customized thermoplastic resin stents. Clinical examinations and pre- and postdecompression panoramic radiographs were analyzed.

RESULTS

The mean relative speed of shrinkage of radicular cysts (RCs; 3.37 cm(2)/month) was faster than those of keratocystic odontogenic tumors (KCOTs; 2.87 cm(2)/month) and unicystic ameloblastomas (UABs; 2.71 cm(2)/month). The relative shrinking size increased linearly in a time-dependent manner for KCOTs (r = 0.849, P < .001), RCs (r = 0.681, P = .319), and UABs (r = 0.146, P = .730); a similar relation was detected between the primary radiolucent area of cystic lesions before decompression and relative shrinking speed after decompression in KCOTs (r = 0.481, P = .032), RCs (r = 0.260, P = .673), and UABs (r = 0.370, P = .366), but patient age did not affect the relative speed of shrinkage (P > .05). Furthermore, the increase in bone density was more significant in RCs than in KCOTs (P = .026) and UABs (P = .012) after decompression.

CONCLUSION

Decompression was effective in reducing odontogenic cystic lesions of the jaw and increasing bone density. For aggressive lesions, secondary definitive surgery was necessary.

Cyclooxygenase-2 expression in keratocystic odontogenic tumour decreased following decompression

Marsupialisation or decompression is frequently performed as a conservative therapy for keratocystic odontogenic tumours (KCOTs). Positive cyclooxygenase-2 (COX-2) expression in the epithelium of KCOTs was recently reported and may be associated with neoplastic invasion and progression. The aim of the present study was to investigate the change in COX-2 expression in the KCOT epithelium following decompression. In this study, 16 pairs of KCOT biopsy specimens obtained during decompression or enucleation were collected and analysed. Formalin-fixed, paraffin-embedded blocks were sectioned and immunohistochemically investigated using anti-COX-2 antibody. The molecular expression was semi-quantitatively evaluated as follows: 0, negative; 1, weakly to moderately positive; and 2, strongly positive. In the samples obtained prior to decompression, the positive staining for COX-2 was immunolocalised to the cell membrane and the cytoplasm, it involved the full thickness of the epithelium and 15 of the 16 specimens (93.8%) exhibited mild to strong positivity. As regards the samples obtained following decompression, only 3 of the 16 specimens (18.8%) exhibited a mild positivity. The expression levels of COX-2 were significantly decreased following decompression (P<0.05). It may be concluded that loss or a significant reduction of COX-2 expression is associated with decompression in KCOTs. However, large-scale studies are required to verify these results and improve our knowledge of the possible involvement of COX-2 in the pathogenic mechanism underlying the development of KCOTs.

Exploring the concept of "inflammatory angiogenesis" in keratocystic odontogenic tumor

Objective: The aim of the present study was to investigate the role of inflammation in angiogenesis of keratocystic odontogenic tumor (KCOT). Study Design: Twenty inflamed and 20 non-inflamed KCOTs were selected based on quantitative scoring of inflammation which was also applied on 20 radicular cysts. Microvessel density was assessed in all samples using CD34 antibody and angiogenesis was compared between the three groups. Statistical analysis was performed using one-way analysis of variance followed by post-hoc Scheffe test and P values less than 0.05 were considered significant. Results: A statistically significant difference in angiogenesis was found between radicular cysts and both inflamed and non-inflamed KCOTs (P < 0.001), but not between inflamed and non-inflamed KCOTs (P =0.347). Conclusion: Based on the results obtained in the present study, it seems that the effect of inflammation on angiogenesis in KCOT is minimal. However further investigation using other methods of evaluation is suggested to fully clarify the role of “inflammatory angiogenesis” in this neoplasm.

Key words:Keratocystic odontogenic tumor, radicular cyst, angiogenesis, inflammation.

Odontogenic keratocysts/keratocystic odontogenic tumours: biological characteristics, clinical manifestation and treatment

BACKGROUND

Odontogenic keratocysts (OKCs) now reclassified as Keratocystic odontogenic tumours (KCOTs) are a clinical entity with a characteristic microscopic picture, kinetic growth and biological behaviour. They arise from the proliferation of the epithelial dental lamina in both maxilla and mandible and occur in patients of all ages. 70-80% of keratocysts are found in the mandible commonly in the angle between the jaw and mandibular branch and maxillary region of the third molar. The cysts are long latent, often symptomless and may attain remarkable dimensions without significant deformation of the jaw bones. They are often found during routine dental X-ray examination. Compared to other types of jaw cyst, odontogenic cysts have a striking tendency to rapid growth and re-occurrence.

AIMS

This review focuses on the biological characteristics, clinical behaviour and treatment of KCOTs.

METHODS

The databases searched were the PubMed interface of MEDLINE and LILACS.

RESULTS AND CONCLUSIONS

Ondontogenic keratinocysts are not currently a diagnostic problem. Orthopantomograms which are today ordinary tools of dental investigation enable diagnosis of clinically asymptomatic cystic lesions. The problem remains the optimal therapeutic approach to reduce the still high likelihood of postoperative recurrence. There is no complete consensus on the ideal operating procedure but cystectomy with delayed extirpation is favoured. An open question also remains the timeliness of screening for postoperative recurrences. Given that the first clinical manifestation of Nevoid Basal Cell Carcioma Syndome (NBCCS) may be lesions of this type, routine histopathological classification supplemented by analysis of immunophenotype should be done. Patients with proven sporadic and especially syndromic OKC should be long term screened. In patients with NBCC preventive X ray examination is recommended only once a year.

Use of decompression tubes in the management of excessively large odontogenic keratocyst

Odontogenic keratocyst (OKC) is a unique cyst because of its locally aggressive behaviour, high recurrence rate and characteristic histological appearance. A radical surgical approach is commonly advocated with morbid and disfiguring results. This approach also presents several reconstructive obstacles especially in anterior mandible. In this case report the authors present a 25-year-old male patient with a large OKC and treatment with decompression followed by enucleation, and chemical cauterisation. This approach though demanding prolonged treatment time and postoperative follow-up decreases the morbidity to a great extent in a young individual. At the same time, it allows an opportunity for the maxillofacial surgeon to preserve the natural dentition, maintain function and safeguard cosmesis. In our case, the authors effectively achieved all the aforementioned objectives. At the same time a radical option of treatment is still left in the armoury if required at a later date.

Secondary healing after removal of large keratocystic odontogenic tumor in the mandible: enucleation followed by open packing of iodoform gauze

PURPOSE

The aim of this retrospective study was to present the findings of an open packing method after enucleation of large keratocystic odontogenic tumors (KCOTs) in the mandible.

PATIENTS AND METHODS

We performed a retrospective case series study of 27 patients with KCOTs larger than 5 cm treated at our institution between September 2003 and September 2008. A conservative surgical treatment was applied, which involved enucleation of the primary lesion and open packing of the residual osseous defect with iodoform gauze for secondary healing. Bone regeneration, tumor recurrence, and surgical complications were observed and analyzed. We used the χ(2) test and Pearson correlation coefficient for statistical analysis.

RESULTS

The postoperative follow-up time was 52.3 months on average (range, 24 to 84 months). The packing gauze was changed every 2 weeks after enucleation, and the total duration for packing was 10.2 months on average (range, 7-15 months). Bone regeneration and satisfactory secondary healing were observed clinically and radiographically after treatment. Only 1 case had a recurrence 6 months after initial treatment, which was attributed to insufficient bony unroofing during enucleation. The recurrent lesion was re-treated by the same method, and no recurrence occurred in the following 6 years. No serious complications from this method of treatment were observed. No significant variables were found to be related to the recurrence.

CONCLUSIONS

Enucleation with subsequent open packing was shown to be a conservative and comfortable treatment for patients and appears to be an effective choice for the management of large KCOTs in the mandible.

Two-stage treatment protocol of keratocystic odontogenic tumour in young patients with Gorlin-Goltz syndrome: marsupialization and later enucleation with peripheral ostectomy. A 5-year-follow-up experience

OBJECTIVE

Keratocystic odontogenic tumour (KCOT) is a benign uni- or multicystic intraosseous odontogenic tumour with potential for local destruction and tendency for multiplicity, especially when associated with Gorlin-Goltz syndrome. We suggest a conservative surgical treatment based on marsupialization and later enucleation with peripheral ostectomy in order to preserve jaw's integrity in young patients.

METHODS

Three young patients affected of nevoid basal cell carcinoma syndrome (NBCCS or Gorlin-Goltz syndrome) presented large and multiple KCOTs, which have been treated following a two-stage surgical strategy. Initially marsupialization was performed and after a mean period of 10 months, contextually to evident reduction in radiological size image, enucleation with peripheral ostectomy was carried out.

RESULTS

All the patients showed high collaboration in daily self-irrigation of the stomia with chlorhexidine 0.2% during the period of marsupialization. Definitive surgical intervention led to complete healing and no signs of recurrence have been observed during a 5-year-follow-up.

CONCLUSIONS

The main advantage of this modality is the preservation of important anatomical structures involved in the lesion and jaw's continuity. Therefore in a selected group of cooperative patients, especially those affected of Gorlin-Goltz syndrome, the surgical protocol exposed allows for a less invasive approach with excellent results avoiding extensive disfiguring procedures.

A technique for long term decompression of large mandibular cysts

Decompression is a conservative treatment that has frequently been used in the treatment of large odontogenic cysts. Techniques described in the recent literature have involved only fixation of a stent to soft tissue. In the present investigators' experiences, this technique has a high failure rate because of the dislodgement of the stent, due to tearing of the sutures over the course of a long-span treatment period. This report describes the use of a molded plastic stent that is fixated to bone and soft tissue, allowing access for daily irrigation during the long-span treatment period.