RESUMO
The keratocystic odontogenic tumor is a benign odontogenic cystic neoplasia characterized by its thin, squamous epithelium with superficial parakeratosis. It has the potential for infiltration and local aggressiveness and has a high rate of recurrence. This neoplasia is predominantly found in males and people of white origin. The mandible is the most frequently involved site, in particular the third molar region, mandibular angle, and ramus. It has a mandible-maxilla ratio of 2:1. Only about twenty cases of peripheral keratocystic odontogenic tumors (PKCOT) have been reported in the international literature. This study presents a case of PKCOT localized in the anterior region of the maxilla, on the vestibular side of the upper left lateral incisor and the upper left canine. The diagnosis and treatment procedures, as based on the literature, are also discussed. Key words:Odontogenic cysts, odontogenic tumors, keratocyst, keratocystic odontogenic tumor.
RESUMO
OBJECTIVES: To evaluate the bone regeneration potential of a new membrane fabricated with polyglycolide acid (PLGA) after being treated with oxygen plasma (PO2), and/or being functionalized with silicon dioxide (SiO2) or titanium dioxide (TiO2) nanoparticles. METHODS: Bone defects (5 mm 3 mm) were produced on the top of 3 experimentation rabbits' skulls and were covered with variously modified PLGA scaffolds. After the animals were sacrificed, neoformed bone (%), mineralized bone (mm), bone resorption (%), osteoclasts/mm2, and intensity of osteosynthetic activity, were assessed under microscope. RESULTS: The following groups were formed depending on the type of membrane: PLGA (control); PLGA/PO2; PLGA/SiO2; PLGA/TiO2; PLGA/PO2/SiO2; and PLGA/PO2/TiO2. The histological sections showed bone layers in advanced stages of formation. The highest percentages of neoformed bone corresponded to PLGA/PO2/SiO2 membranes (59.07%; p = 0.31) followed by PLGA/PO2 barriers (50.27%). The controls showed the lowest mineralization (13.89 mm; p = 0.24). PLGA/TiO2 scaffolds exhibited the least bone resorption (4.45%; p = 0.77) and osteoclasts/ mm2 (1.58; p = 0.86). PLGA/SiO2 and PLGA/TiO2 membranes stimulated the maximum osteosynthetic activity. CONCLUSIONS: The treatment of PLGA barriers with PO2 increased bone regeneration in rabbits. When comparing the effect of PO2/SiO2 and PO2/TiO2, higher percentages of neoformed bone were encountered after silicon-dioxide coating. CLINICAL SIGNIFICANCE: The incorporation of SiO2 nanoparticles onto PO2-treated PLGA membranes was the most promising technique out of those investigated to promote bone formation in rabbits. The addition of SiO2 or TiO2 layers to PLGA substrates may stimulate the osteosynthetic activity, which might be useful to restore bone dimensions in preparation for naturally appearing dental prostheses.
