Recurrent peripheral ameloblastoma in an elderly patient: A case report.

OBJECTIVE: To report a case of recurrent peripheral ameloblastoma (PA) in an elderly patient. BACKGROUND: PA is a benign tumour that affects soft tissues of gingiva or edentulous alveolar areas, exhibiting histopathological characteristics of ameloblastoma. METHODS: A 79-year-old man showed a nodule in the edentulous right mandibular alveolar ridge diagnosed as recurrent PA. CONCLUSION: Clinicians should consider PA as a differential diagnosis of routine nodular lesions affecting the oral mucosa of geriatric patients.

Peripheral Calcifying Odontogenic Cyst: A rare case report.

The Calcifying Odontogenic Cyst (COC) is a simple cyst lined by ameloblastoma-like epithelium with ghost cells. The peripheral COC is a rare lesion and few reports have been published considering its clinical and histopathological features. This article aimed to report on a case of a peripheral COC, discussing its clinical, imaginological and histopathological features. A 9-year-old male patient presented a 10x5 mm painless nodule in the palatal mucosa of the left central incisor. Panoramic, occlusal and periapical radiographs did not show alterations. A computed tomography exam showed a slight soft tissue swelling located in the palatal mucosa of the left maxillary central incisor. An excisional biopsy was performed. The histopathological analysis showed a cystic lesion adhered to an oral mucosa fragment and lined by an ameloblastoma-like epithelium with ghost cells. The diagnosis of peripheral COC was established and the patient has been disease-free for 5 years. Although rare, peripheral COC is an important lesion that should be considered as a differential diagnosis of gingival hyperplastic lesions. Key words:Calcifying odontogenic cyst, odontogenic tumors, peripheral calcifying odontogenic cyst.

Análise crítica de estudos sobre biomateriais à base de fosfato de cálcio e HA, utilizados como enxertos ósseos em animais / Critical analysis of biomaterials, used as bone grafts, in animals studies

O objetivo desta revisão foi abordar o comportamento de diferentes biomateriais à base de fosfato de cálcio e/ou HA, utilizados como enxerto para reparo ósseo, bem como as respostas teciduais obtidas em modelos experimentais animais. A comparação direta entre estudos realizados em condições experimentais diversas é de difícil análise pelas variáveis envolvidas (métodos cirúrgicos, modelos experimentais, sítios de implantação e espécies). Dependendo do sítio de implantação, a arquitetura óssea difere em relação aos ossos cortical e medular, o que pode gerar diferentes tipos de estresse biomecânico e diferentes taxas de formação e remodelação ósseas. As características físico-químicas dos diferentes biomateriais influenciam consideravelmente na capacidade de estimulação da neoformação óssea. Os estudos analisados comprovam a atividade osteocondutiva das cerâmicas de fosfato de cálcio em vários sítios e modelos animais. Em relação às cerâmicas de fosfato de cálcio bifásico (BCP), suas características físico-químicas influenciam diretamente o grau de formação óssea e de sua estabilidade, estando relacionados à dissolução das fases de tricálcio fosfato e hidroxiapatita. Diversos estudos apontam para a utilização promissora do BCP como substituto ósseo e como uma alternativa viável aos enxertos de osso autógeno.

The aim of this review is to highlight the behavior of different calcium phosphate/HA-related biomaterials used as graftings for bone repair, as well as their tissue responses in experimental animal models. The direct comparison among varied experimental conditions is complicated due to the existing variables (surgical methods, experimental models, implantation sites, and selected species). Depending on the local site composition (cortical/marrow bone), different biomechanical patterns arise along with bone formation/remodeling outcomes. The physicochemical characteristics of available biomaterials significantly influence on the ability to form the new bone tissue. The presented studies corroborate the osteoconductive performance of calcium phosphate ceramics in several sites and animal models. Regarding the biphasic calcium phosphate ceramics (BCP), its physical and chemical properties influence on the bone formation degree and stability, being these related to the HA and tricalcium phosphate crystal dissolution rates. Also, several studies point out to the successful use of BCP as bone substitute and a viable alternative to the autogenous bone grafts.