Evaluation of Sociodemographic Factors and Prevalence of Oral Lesions in People Living with HIV from Cacoal, Rondônia, Amazon Region of Brazil.

BACKGROUND: It is necessary to evaluate and understand the prevalence and risk factors of oral lesions (OL) in people living with HIV (PLWH) who were never studied before. The present study aimed to describe the prevalence of OL and its correlation with CD4+ T lymphocytes counts and HIV plasma viral load in PLWH treated in Rondônia. METHODS: A cross-sectional study was carried out at Cacoal city, Rondônia state, Northern Brazil. Sociodemographic, epidemiological, immunologic and virological information of 113 PLWH were collected from medical records and dental examination was conducted to diagnose and classify OL in PLWH. Statistical analysis was performed using relative frequency distribution, ANOVA, Kruskal-Wallis, T-student and Mann-Whitney tests. RESULTS: The overall prevalence of oral lesions was 28.3% (32/113), with candidiasis (7/32; 21.8%) and aphthous ulcer (7/32; 21.8%) being the most prevalent. There was a predominance of females, most patients being married, with a low level of education, a family income of 1 to 3 minimum wages and a single partner. An association was observed between the presence of oral lesions and a high viral load, as well as a lower occurrence of oral lesions in individuals with a higher count of CD4+ T cells. CONCLUSIONS: This study reveals a low prevalence of OL among PLWH, as well as the absence of relationship between HIV viral load, CD4+ T cells count and OL high prevalence.

Key proteins of invadopodia are overexpressed in oral squamous cell carcinoma suggesting an important role of MT1-MMP in the tumoral progression.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the most relevant malignant neoplasm among all head and neck tumours due to its high prevalence and unfavourable prognosis. Tumour invasion and metastasis that affect prognosis are result of a set of complex events that cells with invasive potential use to spread to other regions. These cells use several mechanisms to invade tissues, including a type of finger-like membrane protrusion called invadopodia. This study aims to investigate the immunoexpression of invaopodia related-proteins TKs5, cortactin, TKs4 and MT1-MMP in OSCC and correlate it to clinicopathological data. METHODS: An immunohistochemical evaluation of fifty cases of OSCCs and 20 cases of oral mucosa (OM) were assessed. The expression of invadopodia proteins were analysed in comparison to normal tissue (OM) and correlated to different clinical-stage and histological grade of OSCC. RESULTS: TKs5, cortactin, TKs4 and MT1-MMP were significantly overexpressed in OSCC when compared to OM (p < 0.0001). Among tumour stages, TKs5 showed a statistical difference in immunolabelling between stage I and III (p = 0.026). Cortactin immunolabelling was statistically higher in grade I than in grade II and III. No differences were seen on TKs4 expression based on tumour staging or grading. MT1-MMP was higher expressed and showed statistical difference between stages I and III and grades I compared to II and III. CONCLUSIONS: The invadopodia related-proteins were found to be overexpressed in OSCC when compared to OM, suggesting invadopodia formation and activity. Besides overexpressed in OSCC, cortactin, TKs4 and TKs5 showed no or ambiguous differences in protein expression when compared among clinical-stages or histological grades groups. Conversely, the expression of MT1-MMP increased in advanced stages and less differentiated tumours, suggesting MT1-MMP expression as a promising prognostic marker in OSCC.

Traumatic enucleation of the left globe after a road traffic accident - A case report of an uncommon occurrence in maxillofacial trauma.

INTRODUCTION: Serious injuries of the globe are uncommon in closed maxillofacial trauma, as the anatomical configuration of the orbit offers important protective mechanisms against external trauma. Thus, the objective of this work is to report a case of a rare traumatic enucleation of the globe resulting from maxillofacial blunt trauma. PRESENTATION OF CASE: A 42-year-old man was hit by a car with a major complaint of facial pain. The patient had several facial fractures including: Le Fort I, naso-orbit-ethmoidal, anterior sinus wall and an exposed fracture of the orbit-zygomatic complex (OZC). The patient underwent to open reduction and internal fixation of facial fractures and enucleation of the left globe, however, evolved with postoperative infection and complications associated with, a so far unknown, type 2 diabetes. After secondary surgeries for removal infected bones and diabetes control, all injuries were fully healed, and the patient remained with major sequels. DISCUSSION: In this case, we hypothesized a high-energy trauma resulting in multiple facial fractures, especially involving the OZC, dislocated the thick lateral wall of the orbit within the orbital cavity and reduced the orbital volume. This resulted in an exaggerated increase in intraorbital pressure, which exceeded the capacity of all anatomical protective mechanisms of the globe, and pushed the globe outwards, causing a complete avulsion. CONCLUSION: Besides all anatomical structures to protect the globe, rarely high energy maxillofacial trauma can cause severe damage to the globe resulting in loss of vision and globe avulsion.

Prevalence and Molecular Epidemiology of Human T-Lymphotropic Virus (HTLV) Infection in People Living With HIV/AIDS in the Pará State, Amazon Region of Brazil.

The human T-lymphotropic virus (HTLV) is part of the group of retroviruses that share similar routes of transmission to the human immunodeficiency virus (HIV). Coinfection of these viruses can affect the clinical course of both infections, and reports have shown a quicker progression to AIDS and the development of HIV-related opportunistic infections. The current study investigated the demographic characteristics, prevalence, and the subtypes of HTLV among people living with HIV/AIDS (PLWHA) in the State of Pará, Northern Brazil. Blood samples were obtained from patients who were attending a reference unit that provides medical assistance to HIV-infected individuals in the State of Pará, Brazil, during the period of May 2016 to June 2017. Plasma samples were screened by ELISA tests to detect antibodies anti-HTLV-1/2. DNA and viral types were identified by real-time polymerase chain reaction (qPCR). All samples with viral DNA were submitted to nested PCR and nucleotide sequencing. The overall coinfection rate was 1.4% (5/368), and all samples were from subtype HTLV-1a. No cases of HTLV-2 infection were detected. The prevalence of HTLV-1 was higher in females (80%), individuals between 31 and 50 years of age, heterosexual, unmarried, with low monthly income, with secondary educational level or higher, sporadic condom usage, limited number of sexual partners, and no history of sexually transmitted infections. All samples from HTLV-1-infected patients were identified as strains belonging to the subtype 1a (Cosmopolitan), subgroup A (Transcontinental). This study identified that the prevalence of HIV/HTLV coinfection has dropped from 8 to 1.3% in the current investigation. There was a shift of HTLV subtype from a predominance of HTLV-2 infection in the past to an actual exclusively HTLV-1a. There was no significant association between economic, sociodemographic, and behavioral characteristics in HIV/HTLV coinfection.

Surgical debridement as a treatment strategy for cervicofacial actinomycosis-Literature review and case report.

INTRODUCTION: Actinomycosis is a rare chronic disease caused by bacterial infection of the Actinomyces genus. Standard treatment usually involves drainage and high doses of antibiotic therapy, which takes between 6-12 weeks for complete resolution. PRESENTATION OF CASE: A 57-year-old male was admitted with soft tissue infection-like inflammation of the parasymphysis region, further diagnosed as cervicofacial actinomycosis. Treatment comprised of surgical debridement associated with antibiotic therapy, which took only 4 weeks for complete healing. DISCUSSION: Although surgical debridement isn't part of the standard treatment, it has shown to be an interesting tool for promoting quick healing and infection control. CONCLUSION: The authors reported a successfully treatment of cervicofacial actinomycosis using surgical debridement as an adjuvant therapy, promoting faster healing, reducing antibiotic therapy time, costs and risks of bacterial resistance, which must be considered as an alternative approach in similar cases.

Low prevalence of human pegivirus 1 (HPgV-1) in HTLV-1 carriers from Belém, Pará, North Region of Brazil.

INTRODUCTION: Human pegivirus 1 (HPgV-1) is a single-stranded, positive-sense RNA virus belonging to the Flaviviridae family with limited cause-effect evidence of the causation of human diseases. However, studies have shown a potential beneficial impact of HPgV-1 coinfection in HIV disease progression. Human T lymphotropic virus-1 (HTLV-1) is a retrovirus known for causing diseases, especially in muscle and white blood cells, in approximately 5% of patients. Thus, this study aimed to investigate the potential effects of an HPgV-1 infection in patients carrying HTLV-1 in the state of Pará in the North Region of Brazil. METHODS: A group of HTLV-1 carriers was compared to healthy controls. Blood samples were collected, data from medical regards were collected, and a questionnaire was administered. HPgV-1 and HTLV-1 positivity was determined by quantitative polymerase chain reaction (qRT-PCR). The data were analyzed to correlate the effects of HPgV-1 coinfection in HTLV-1 carriers. RESULTS: A total of 158 samples were included in the study: 74 HTLV-1-positive patients (46,8%) and 84 healthy controls (53,2%). The overall HPgV-1 positivity rate was 7.6% (12/158), resulting in a prevalence of 5.4% (4/74) and 9.5% (8/84) in HTLV-1 carriers and healthy controls, respectively. No significant differences were found when comparing any clinical or demographic data between groups. CONCLUSION: This study indicated that the prevalence of HPgV-1 infection is low in HTLV-1 carriers in Belém, Pará, and probably does not alter the clinical course of HTLV-1 infection, however, further studies are still needed.

Prevalence of syphilis in female sex workers in three countryside cities of the state of Pará, Brazilian Amazon.

BACKGROUND: Syphilis is a sexually transmitted infection (STI) transmitted from person to person mainly by sexual intercourse or through vertical transmission during pregnancy. Female sex workers (FSWs) are exposed especially to syphilis infection, and besides all the efforts to control the spread of STIs, syphilis prevalence is still rising, mainly occurring in low-income countries. This study aimed to investigate the syphilis prevalence, demographic characteristics and sexual habits among FSWs in the Amazon region of Brazil. METHODS: A cross-sectional study was carried out including 184 FSWs from 3 countryside cities of the state of Pará, Amazon region of Brazil. A venereal disease research laboratory test and an indirect immunoenzyme assay to test antibodies against Treponema pallidum were used for screening syphilis infection, while sexual habits and demographic data information were collected through a semi-structured questionnaire. Data was analyzed comparing groups with/without syphilis. Poisson regression models were used to estimate the reasons of prevalence (RP). RESULTS: The overall prevalence of syphilis was 14.1% (95% CI = 9.8-17.8). FSWs had between 15 and 56 years of age, most were unmarried (65.7%), had attended less than 8 years of formal education (64.1%), had between 10 and 20 partners per week (64.1%), and reported no previous history of STIs (76.1%) and regular use of condom (52.7%). Low level of education attending up to the primary school (RP adjusted = 3.8; 95% CI = 1.4-9.2) and high frequency of anal sex during the past year (RP adjusted = 9.3; 95% CI = 3.5-28.7) were associated with a higher prevalence of syphilis. CONCLUSIONS: A high prevalence of syphilis among FSWs in the Brazilian Amazon region was identified, showing that syphilis is more likely to be transmitted in FSW working in low-income areas, which is attributed to the low level of education. Anal intercourse was found as a risk factor associated with syphilis. Health programs focused on risk populations appear as a rational way to control syphilis spread, which is a rising problem in Brazil and in other several countries.

Incidence of respiratory syncytial virus infection in children with congenital heart disease undergoing immunoprophylaxis with palivizumab in Pará state, north region of Brazil.

BACKGROUND: Palivizumab prophylaxis for the human respiratory syncytial virus (HRSV) has been reported to reduce the risk of hospital admissions related to HRSV in children with congenital heart disease (CHD). These children are at high risk of developing severe lower respiratory tract infection (LRTI) due to HRSV infection. Our goal was to evaluate the incidence of HRSV infection in children with CHD after being submitted to immunoprophylaxis with palivizumab in Pará state, North region of Brazil. METHODS: A prospective and observational cohort study was performed in children ≤2 years of age with CHD who received palivizumab immunoprophylaxis between January 1 and June 31, 2016. A questionnaire about basic non-medical care measures was applied to parents/legal representatives. Data on patients' demographic characteristics, household environment, and respiratory infections were evaluated. HRSV infection was determined by qPCR. RESULTS: There were 104 children enrolled in this investigation and the results showed a mean age of 10.6 months, an average weight of 7.3 kg and 3.5 doses of palivizumab per children during seasonality of HRSV. Respiratory infection was observed in 27.9% of cases, of which 9.6% were LRTI. No case of children who received palivizumab immunoprophylaxis and developed influenza-like symptoms tested positive for HRSV. CONCLUSION: Although the lack of a control group doesn't allow to affirm the effectiveness of HRSV passive immunization, the immunoprophylaxis with palivizumab appeared to be totally efficient in preventing respiratory infection by HRSV in children up to two years of age with CHD.

Abnormal activation of the Akt signaling pathway in adenoid cystic carcinoma.

PURPOSE: Adenoid cystic carcinoma (ACC) is an intriguing lesion because it shows a slow growth in the beginning, but a late poor prognosis due to perineural invasion, metastasis and recurrence. This study aimed to investigate whether Akt signaling would be deregulated in adenoid cystic carcinoma and its consequence in the expression of associated proteins. METHODS: The expression of the Akt, p-Akt, NFκB, ß-catenin, cyclin D1 and COX-2 was assessed by immunohistochemistry in 10 cases of ACC, 17 cases of pleomorphic adenoma (PA), and 7 cases of normal salivary gland (NSG). RESULTS: p-Akt was overexpressed in ACC when compared to NSG. NFκB, ß-catenin, and COX-2 were overexpressed in ACC and PA when compared to NSG. Most proteins were slightly higher expressed in ACC than in PA, but they never reached significance. p-Akt expression positively correlated with NFκB, ß-catenin, cyclin D1 and COX-2 in ACC and PA, while this correlation trended to be negative in for these proteins (except for NFκB) in NSG using Person's correlation analysis, but without reaching significance. CONCLUSIONS: Our results indicate an abnormal activation of Akt signaling pathway, which can be an important regulator of tumor biology in ACC. Activated Akt correlated with the expression of NFκB, ß-catenin and COX-2, which can potentially influence cell survival in ACC.

Prevalence of dental anomalies on panoramic radiographs in a population of the state of Pará, Brazil.

INTRODUCTION: Dental anomalies (DAs) are the result of disorders that are able to modify the shape, number, size, and structure of teeth. This study aimed to evaluate the prevalence of DAs using panoramic radiographs in a population of the City of Belém, northern Brazil. MATERIALS AND METHODS: In this study, 487 panoramic radiographs were evaluated searching for DAs. Dental records were reviewed for diagnostic confirmation. DAs related to the shape, number, size, and structure of teeth were investigated. RESULTS: Our results showed a DA prevalence of 56.9%. The most prevalent DA was taurodontism, which was present in 27.19% of cases. Root dilaceration was the second most prevalent DA in adults, whereas hypodontia was the second most prevalent DA in children. A total of 13 DAs were found. CONCLUSIONS: Dental anomalies were present in over half of the sample, and most of them were related to the shape of the teeth. Although there was a high prevalence of shape-related DAs, these alterations are generally of lower severity, and most do not require specific treatment. However, in 19.25% of cases, DAs were found involving the number, size and structure of the teeth. These DAs should be diagnosed and treated early, avoiding thus more serious complications.

Oral capillary hemangioma: a clinical protocol of diagnosis and treatment in adults.

PURPOSE: Hemangiomas are benign vascular anomalies characterized by benign proliferation of blood vessels. There are no well-defined criteria for the diagnosis and treatment of oral capillary hemangioma (OCH). The objective of this study is to report a safe, effective, and low-cost protocol for diagnosis and treatment of OCH. MATERIALS AND METHODS: Eight patients were diagnosed with OCH, through two physical examination maneuvers-the diascopy and head lowering maneuver with abdominal compression (HLMAC). The treatment performed was sclerotherapy with ethanolamine oleate, weekly, until the disappearance of the lesion. No local anesthetics were administered prior to the sclerosing agent injection. RESULTS: All cases showed a complete remission of the lesions after sclerotherapy. There were no visible scars or compromise esthetics or normal function, and there was no evidence of recurrence. Only one patient had superficial ulceration, which remained asymptomatic and healed without specific treatment. CONCLUSIONS: This protocol was effective in the diagnosis of OCH through two physical examination maneuvers with low-cost and easy implementation, the diascopy and the HLMAC. The low concentration associated with a reduced amount of the sclerosing agent was responsible for the excellent results in the cases treated.

Zygomaticomaxillary complex fracture in a zygomatic bone affected by monostotic fibrous dysplasia: a very rare association.

The association between fibrous dysplasia (FD) and fractures is very rare. This paper reports the case of a zygomaticomaxillary complex fracture in a bone affected by FD, a 29-year-old man who was involved in a bicycle accident and who subsequently presented with a zygomaticomaxillary complex fracture. Computed tomography revealed multiple fractures of the left zygomaticomaxillary complex with dysplastic bone alterations. Fracture lines occurred near transitional areas between the lesion and healthy bone. The patient was treated through an intraoral approach by an open reduction and internal fixation procedure, using a titanium miniplate and screws. An incisional biopsy was performed through the maxillary sinus to confirm the diagnosis of FD. After 12 months of follow-up, there were no postoperative complications. This paper reports a rare association thought to be caused by irregular trabecular bone deposition, which increases bone thickness/resiliency and thus increases its clinical fracture resistance.

Solitary giant neurofibroma of the mental nerve: a trauma-related lesion?

Neurofibroma is a benign neoplasm derived from peripheral nerves whose etiology is still unclear. It may present as a solitary lesion or be associated with other diseases such as neurofibromatosis type I and II syndrome. This paper aims to report an extremely rare case of a solitary giant neurofibroma of the mental nerve whose etiology was related to a local trauma. A 14-year-old female patient presented an extensive left facial mass with a size of 7 × 5 × 4 cm, located between the teeth 33 and 37 in the mandible region. It has begun to grow 3 months after a local trauma. Imaging studies were suggestive of a soft-tissue lesion, with minimal bone changes and maintaining the integrity of the mandibular canal and mental foramen. Histopathological tests showed spindle cells with undulated and hyperchromatic nuclei, and sparse cytoplasm in a stroma composed of dense fibrous connective tissue. Immunohistochemistry revealed positive expression for the proteins S-100 and vimentin, confirming the diagnosis of neurofibroma. The patient underwent surgical removal of the lesion by intraoral approach and evolved with an excellent cosmetic result and no signs of recurrence after 2 years of follow up. We report a rare case of solitary giant neurofibroma whose etiology was related to a local trauma. To our knowledge, this is the first report of a mental nerve neurofibroma. Although the etiology remains unclear, we suggest the investigation of local trauma as a possible etiologic factor for solitary neurofibromas of the jaw.

Matrix metalloproteinases, tissue inhibitors of metalloproteinases, and growth factors regulate the aggressiveness and proliferative activity of keratocystic odontogenic tumors.

OBJECTIVE: The objective of this preliminary study was to evaluate the expression of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs) and growth factors in keratocystic odontogenic tumors (KOTs). STUDY DESIGN: The expression of MMPs, TIMPs, growth factors, and the extracellular signal-regulated kinase (ERK) 1/2 signaling pathway were assessed by immunohistochemistry in 15 cases of KOT and 4 cases of calcifying cystic odontogenic tumor (CCOT). RESULTS: KOT samples expressed significantly higher amounts of MMPs, TIMPs, growth factors, epidermal growth factor receptor (EGFR), and ERK compared with CCOT samples, with the exception of MMP-2 and TIMP-1. CONCLUSIONS: MMP-9, TIMP-2, EGF and transforming growth factor α act together and likely regulate the proliferation and aggressiveness of KOT. ERK-1/2 serves as the transducer of signals generated by these proteins, which signal through the common receptor, EGFR. This process may be related to the increased proliferation and aggressiveness observed in KOT.

Oral myiasis: does an indication for surgical treatment still exist? Two case reports.

OBJECTIVE: Oral myiasis is a rare infection for which treatment protocol has not yet been established. This article presents 2 cases treated with a combination of topical application of sulfuric ether and surgery. The reasons for the use of surgical therapy, as well as the possible advantages and disadvantages of drug-based treatments, are discussed. CASE REPORT: Two cases of oral myiasis are described, the first being observed in a 9-year-old child with hypotonic cerebral palsy, and the second in a 52-year-old adult, alcohol-dependent, both showing infection in the gingival sulcus. Both cases were successfully treated in a process that involved topical application of sulfuric ether, mechanical removal of larvae, and surgical debridement. CONCLUSIONS: Oral myiasis can be treated effectively with surgery after topical application of sulfuric ether. The use of drugs may suggest a therapeutic alternative, but still requires further study and experience to be implemented, especially in individuals with neurological disorders.

Osteotomia e odontossecção: quando realizá-las em cirurgias de terceiros molares superiores retidos / Osteoctomy and tooth section: when should be used in upper third molar surgery

Introdução: a remoção de dentes retidos é o procedimento cirúrgico mais realizado porCirurgiões Bucomaxilofaciais e, mesmo assim, permanece como um dos mais desafiadores.Neste trabalho avaliou-se a necessidade de realização de osteotomia e odontossecçãopara a éxerese de terceiros molares superiores retidos. Métodos - Foram analisados 300casos cirúrgicos de 3º molares superiores retidos e avaliada a necessidade de osteotomiae odontossecção para sua avulsão. Os autores basearam-se na classificação de Winter paraobtenção de um referencial e relacionaram às técnicas cirúrgicas necessárias para extraçãoem cada tipo de angulação. Resultados - Dentre as retenções mais comuns, a mesioangularfoi a que exigiu técnica mais laboriosa, necessitando de osteotomia em 73,3% dos casos.Odontossecções não foram realizadas e osteotomias estiveram presente em 44% de todosos casos. Encontrou-se 6 casos de retenções raras. Conclusão – Não houve necessidadede odontossecções e osteotomias foram executadas em 44% das situações. Nas retençõesde maior prevalência, a mesioangular exigiu maior percentagem de osteotomias (73,3%),seguido da distoangular (65,6%) e a vertical (19,6%).

Introduction: the removal of teeth retained is the surgical procedure more performed byOral Maxilofacial surgeons and still remains as one of the most challenging. This articlefocuses on the need for realization of odontosection, osteotomy for the excision of retainedup third molars. Methods - We analyzed 300 cases of surgical up 3rd molars retained andassessed the need for osteotomy and odontosection for its avulsion. The authors were basedon the classification of Winter to obtain a reference and related to the surgical techniquesnecessary to extract every kind of angle. Results - Among the most common retention tomesioangular demanded that the technique was more laborious, requiring osteotomy in73.3% of cases. Odontosection not been implemented and osteotomies were present in44% of all cases. We found 6 cases of rare retentions. Conclusion - There wasn´t need forodontosections and osteotomies were performed in 44% of cases. In the higher prevalenceretentions, the highest percentage of osteotomies was in mesioangular (73.3%), followedby distoangular (65.6%) and vertical (19.6%).

Oral piercings: immediate and late complications.

PURPOSE: Oral piercings have a long history as part of religious, cultural, or sexual symbolism in many traditional tribes; currently, these ornaments have wide acceptance among young people. Several oral and systemic complications may be associated with this practice; however, limited data related to these complications can be obtained in the literature. PATIENTS AND METHODS: This study includes 42 cases of oral piercings in 39 young adults, who were using or had used oral piercings, and the complications associated with their use. RESULTS: Immediate complications occurred in 29 cases, including excessive bleeding (69%) and pain (52.3%) as the most representative. Two cases of syncope were found. Late complications related to the piercing insertion site were observed in 97.6% of cases, with pain and swelling being present in 92.9% and 61.9% of cases, respectively. Dental pain and lacerations on the tongue represented the most prevalent complications associated with the surrounding tissues, accounting for 33.3% and 31% of cases. CONCLUSIONS: The use of oral piercings is related to a series of mainly local complications, and individuals who decide to use piercings should be aware of such complications. Individuals wishing to get a part of their body pierced should do so with qualified professionals and should regularly visit the dentist so that a regular control is achieved, thus ensuring the early detection of the adverse effects associated with this practice.

Expression of metallothionein in ameloblastoma. A regulatory molecule?

BACKGROUND: Ameloblastoma is a benign odontogenic tumor, exhibiting local invasiveness and high rate of recurrence. Metallothionein is a protein associated with tumorigenesis, serving as prognostic factor in different neoplasms. We are interested in mechanisms underlying ameloblastoma local invasiveness. Thus, we decided to analyze expression of metallothionein in this tumor. MATERIALS AND METHODS: An immunohistochemical evaluation of metallothionein in ameloblastoma was carried out. As control, we assessed expression of the same molecule in calcifying cystic odontogenic tumor (CCOT), a non-invasive odontogenic neoplasm with ameloblastomatous epithelium. RESULTS: We studied 12 cases of solid/multicystic ameloblastomas. Metallothionein was observed in all samples. This molecule was observed in columnar cells in the periphery and in central polyhedral cells. CCOT (four cases) also showed the presence of metallothionein. Morphometry of stained areas showed that expression of metallothionein in ameloblastoma was significantly higher compared to CCOT (P < 0.0001). CONCLUSIONS: This protein may have an impact on ameloblastoma behavior. Metallothionein would act as a zinc reservoir for important proteases related to ameloblastoma biology, such as MMPs. This protein could also display pro-mitotic and anti-apoptotic features in the tumor.