Studies with MMP9 gene promoter polymorphism and nonsyndromic cleft lip and palate.
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Biomedical subjects
Publications and source records attributed to Renato Menezes.
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OBJECTIVE: The purpose of this study was to determine the expression of receptor activator of NFkappaB ligand (RANKL) and osteoprotegerin (OPG) associated with bone destruction in periapical cysts and granulomas. STUDY DESIGN: Forty human dental chronic periapical lesions were collected after periapical surgery. The lesions collected were fixed in 10% buffered formalin and histologically processed. At least 2 sections of each specimen were stained with hematoxylin and eosin for microscopic diagnosis. After that, 10 human periapical granulomas and 10 cysts were selected for immunohistochemical analysis for RANKL, OPG, and CD68+. RESULTS: Polymorphonuclear neutrophils, macrophages, endothelial cells, and lymphocytes were stained for RANKL and OPG in both lesions. Epithelial cells were also stained for RANKL and OPG in periapical cysts. Quantitative analysis was conducted and the results were expressed as a ratio of the number of immunostained cells over the total number of cells in the field (n = 100). The ratio of RANKL+/total cells was higher than OPG+/total cells in periapical granulomas (0.553 +/- 0.153 and 0.483 +/- 0.189, respectively; P < .0012; paired t test) and in cysts (0.519 +/- 0.09 and 0.339 +/- 0.117, respectively; P < .0001; paired t test). The ratios of OPG+/total cells (P < .0001; paired t test) and RANKL+/total cells (P < .0322; paired t test) were greater in granulomas than in cysts. However, the ratio RANKL+/OPG+ in granulomas (1.336 +/- 0.723) and cysts (1.404 +/- 0.385) was not significantly different. The ratio of CD68+/total cells was significantly higher in granulomas (0.381 +/- 0.040) than in cysts (0.307 +/- 0.068) (P < .0001; unpaired t test with Welch correction). CONCLUSION: Taking into account the limitations of the experimental approach employed, our findings indicate the presence of RANKL and OPG in cysts and granulomas, strongly suggesting the involvement of these gene products in the development of periapical lesions.
The accuracy of the electronic apex locator feature of Tri Auto ZX was assessed. Twenty distobuccal roots were selected and, after endodontic access, placed in plastic cylinders filled with 2% agar until completely covered. The roots were divided in two groups according to the calibration of the automatic apical reverse mechanism of Tri Auto ZX, at 1 and 2 mm from the apical foramen. Preparation was performed with ProTaper instruments connected to the device. Afterwards, the last file used was introduced into the canal and fixed in place with acrylic resin. The roots were removed from the agar and ground until exposure of the file. The distances between file tip and apical foramen were submitted to statistical analysis. The distances reached were actually shorter than the preset distances in every case, however, they were considered clinically acceptable. Setting the reverse mechanism at 1 mm was more reliable than at 2 mm.
Orthodontically induced inflammatory root resorption is an unfortunate consequence of orthodontic movement. It is an adverse effect of an otherwise predictable force application. The degree of the inflammatory process depends on various factors such as amount of force, bone quality, aggressiveness of the resorbing cells and individual variation. Orthodontists should keep track of tooth movement both clinically and radiographically in order to detect any root resorptions and reevaluate the case. This case report presents the treatment outcome (4-year follow up) of five teeth with different and extensive inflammatory root resorptions following orthodontic treatment.
Root fracture is one of the consequences of dental traumatisms. The possibility of saving the fractured tooth depends on the level of the fracture and also on pulp vitality. This case report describes the use of MTA in association to an intracanal post to reinforce a maxillary central incisor with horizontal root fracture in its cervical third.
Root perforations are undesired complications of endodontic treatment. In the recent literature, MTA has been regarded as an ideal material for perforation repair. This article describes a case report where an iatrogenic supracrestal perforation was repaired successfully with mineral trioxide aggregate (MTA).
The treatment of persistent bone defects has encouraged the search for proper techniques or bone substitutes. In Dentistry, a common problem in the treatment of periodontal bone defects is the growth of tissues within the lesion, such as the junctional epithelium, which impair regeneration of these tissues. Guided tissue regeneration (GTR), based on the separation of the tissues by means of membranes or barriers, was developed in an attempt to improve periodontal regeneration. The aim of this study was to histologically evaluate the tissue response to a membrane of demineralized bovine cortical bone implanted in the subcutaneous tissue of rats. The study periods were 1, 3, 7, 15, 30 and 60 days after implantation. Analysis of the histological sections demonstrated a moderate to intense inflammatory response at 1 and 3 days, moderate at 7 and 15 days, and almost absent at 30 and 60 days. Resorption of the membrane began 15 days after implantation, and at 60 days only remnants could be detected in some animals. We concluded that the demineralized bovine cortical bone membrane was well tolerated by the tissues and is completely resorbed after 30-60 days by mononuclear cells and multinucleated giant cells, which disappear upon completion of the process.
OBJECTIVE: The purpose of this study was to investigate the pulpal response of dogs' teeth after pulpotomy and direct pulp protection with MTA Angelus, ProRoot, Portland cement and white Portland cement. STUDY DESIGN: Seventy-six teeth were treated with these materials. One hundred twenty days after treatment, the animals were sacrificed and the specimens removed and prepared for histological analysis. RESULTS: All the materials demonstrated similar results when used as pulp-capping materials. Pulp vitality was maintained in all specimens and the pulp had healed with a hard tissue bridge. CONCLUSION: The materials used in this study were equally effective as pulp protection materials following pulpotomy.
Avulsions are very common in a school setting. Teachers are often requested to help in such emergency situations. A survey consisting of seven simple questions regarding dental avulsion was answered by 60 teachers from five different elementary schools in Rio de Janeiro, Brazil, in order to evaluate their knowledge on the subject and establish a guideline to be followed when an accident of this type happens. A lack of technical information was observed among the teachers; most of them answered intuitively rather than on an informative basis. This study showed the need of a more effective communication between dental professionals and school teachers in order to better handle dental emergencies.