Polyurethane and PTFE membranes for guided bone regeneration: Histopathological and ultrastructural evaluation

Objective: The purpose of this study was to research a membrane material for use in guided bone regeneration. Study design: In this study, 25 male Wistar rats were used to analyze the biocompatibility and degradation process of biomembranes. The morphological changes in subcutaneous implantations were assessed after 7, 14, 21, 28 and 70 days. The materials were made of polyurethane polymer (AUG) obtained from vegetal oil (Ricinus communis) and polytetrafluoroethylene membrane (PTFE). The surface characteristics of the physical barriers in scanning electronic microscopic (SEM) were also evaluated. Results: In both groups, the initial histological analysis showed moderate inflammatory infiltrate, which was predominantly polymorphonuclear. There was also a presence of edema, which was gradually replaced by granulation tissue, culminating in a fibrous capsule. In the AUG group, some multinucleated giant cells were present in the contact interface, with the space previously occupied by the material. However, membrane degradation was not observed during the period studied. According to the present SEM findings, porosity was not detected in the AUG or PTFE membranes. Conclusion: The researched material is biocompatible and the degradation process is extremely slow or may not even occur at all.

Double teeth in primary dentition: Report of two clinical cases

Odontogenic anomalies can occur as a result of conjoining or twinning defects. These include fusion, gemination and concrescence. This article presents two case reports of double teeth. In the first case reported, a 4-year-old white boy presented primary double teeth associated to the absence of the right permanent mandibular lateral incisor. In the second case, a 5-year-old white girl had a family history of anomaly in primary dentition. The girl and her mother presented double teeth in the primary dentition. Her mother showed hypodontia in the permanent dentition. Extra and intra oral clinical examination was made in both cases. Radiographic analyses showed the involvement of the permanent tooth. Authors conclude that double teeth in primary dentition have to be carefully analysed as they may be associated with anomalies in the permanent dentition. Correct diagnosis of the condition implicates in a better prognosis for the patient.

Ameloblastic fibro-odontoma: A case report

Ameloblastic fibro-odontoma (AFO) is a rare, benign, slow-growing odontogenic tumor, generally asymptomatic and more prevalent in children and adolescents. We report a case of AFO in the mandible of an eight-year-old Caucasian male patient, and review the literature. Intraoral examination revealed a swelling extending from the deciduous second molar to the retromolar triangle, covered with normal mucosa. A panoramic radiograph showed a large, well-demarcated radiolucency with radiopaque areas. The provisional diagnosis was of AFO, and so an incisional biopsy was performed. Histologically, the lesion was composed of connective tissue resembling the dental papilla, with epithelial strands or islands, as well as denticles and amorphous masses of enamel and dentin consistent with a diagnosis of AFO. Surgical excision and curettage of the lesion were performed. The patient has been monitored for eight years and the lesion has not recurred.

Intraosseous foreign-body granuloma in the mandible subsequent to a 20-year-old work-related accident

The purpose of this article was to describe the clinical and microscopic features of an intraosseous foreign-body granuloma in the mandible that developed after the traumatic implantation of metal fragments during a work-related accident. A 65-year-old male patient had a severe pain in the body of mandible. Clinical examination showed facial asymmetry and a scar, extending to the left mental region. Intraoral examination revealed a soft mass involving the left alveolar bone with normal appearance of the mucosa surface. Panoramic radiographs showed a radiolucent lesion along the mandible extending from the central incisive to the first molar. Computed tomography revealed an osteolytic mass in the same area. His medical history included a work-related accident twenty years prior to evaluation. During the biopsy an important amount of bright metal-like pieces surrounded by soft tissue were found. A microscopic examination showed a foreign body associated with an aggregation of multinucleated giant cells. The final diagnosis was a foreign body granuloma. Even though foreign-body granulomas in the mandible are rare lesions, dentists should be familiar with their features and include them in the differential diagnosis of tissue masses.

Porous titanium for biomedical applications: An experimental study on rabbits

Objective: The aim of this study was to carry out an in vivo assessment of bone ingrowth in two different types of porous titanium -the first being completely porous, and the second with a porous surface and dense nucleus, manufactured by powder metallurgy- and to evaluate their mechanical properties. Study design: Ten scaffolds from each group were submitted to metallographic analysis and compression tests. Next, two scaffolds of each type were inserted into 14 rabbits, which were sacrificed 8 weeks after surgery. The samples were submitted for histological examination. Results: Metallographic analysis revealed interconnected pores, and the average interconnected pore diameter was about 360 mm, with 36% total porosity. The totally porous titanium samples and the titanium samples with porous surface and dense nucleus showed an average compressive strength of 16.19 MPa and 69.27 MPa, respectively. After 8 weeks, the animals showed bone ingrowth, even into the most internal pores. Conclusions: The pore morphology was effective in permitting bone ingrowth in both groups. Titanium scaffolds with a porous surface and dense nucleus showed the best mechanical properties and most adequate interface.

Rational use of antimicrobials in dentistry during pregnancy

The use of medicines during pregnancy deserves special attention from dentists due to the potential risks to fetal development. The prescription of antimicrobial drugs during this period must be based not only on the etiology of the disease but also on the drug's effect on the embryo, which may be toxic, possibly leading to irreversible lesions. Interest in studies of the teratogenic effects of drugs increased in response to reports of the high incidence of phocomelia in patients treated with thalidomide. Although teratogenicity has long been known, pregnant women today are still exposed to this risk. The effects of drugs depend on the level of susceptibility of the fetus and on the period of exposure during pregnancy. In this context, and considering the paucity of studies on this subject in dentistry, the aim of this review was to offer an up-to-date compilation of data on the antimicrobial drugs most frequently used during pregnancy and the effects of their use.

Effect of low-calcium diet and grind diet on bone turnover of ovariectomized female rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biocompatibility of a chlorhexidine local delivery system in a subcutaneous mouse model

Objective: This study aimed evaluating histologically and histomorphometrically the response of the conjunctive tissue face to the implant of chlorhexidine chips in the subcutaneous tissues of rats. Study Design: In this research 35 male rats Wistar were used to analyze the biocompatibility and the degradation process of chlorhexidine chip. In each animal, it was made 2 incisions for subcutaneous implantation of chlorhexidine chip (test group) and a polytetrafluorethylene membrane (control group). The morphological changes in subcutaneous implantations were assessed after 1, 3, 5, 7, 10, 14, 21 days. The data were submitted to Friedman nonparametric test to analyze the comparisons among observation periods and to allow the comparison among groups. Results: Differences were found in the analysis of the inflammatory response when comparing the tested materials (p values <= 0.05). In test group was observed hemorrhage, edema and intense inflammatory infiltrate predominantly neutrophilic around material. From 3-day and subsequent periods was verified granulation tissue externally at this infiltrate. From 10-day on was observed crescent area of degradation of chlorhexidine chip, associated with neutrophilic and macrophagic infiltrate, that maintained until 21-day. In the control group, moderate inflammatory infiltrate was observed initially, predominantly polymorphonuclear, edema and granulation tissue 3-day period. The inflammatory infiltrate was gradually replaced for granulation tissue, culminating in a fibrous capsule. Giant multinucleate cells situated at contact interface with the coating was examined since 3-day and persisted until 21-day. Conclusion: The chlorhexidine chip induces an intense acute inflammatory response at subcutaneous tissue of rats. Therefore, at conditions of this study was not biocompatible.

Calcium sulfate and PTFE nonporous barrier for regeneration of experimental bone defects

The aim of the study was to evaluate the possibility to obtain guided bone regeneration with two types of physical barriers (calcium sulfate and PTFE nonporous barrier) in surgical defects created in rat parietal bones. In the right parietal bone the calcium sulfate barrier filled out the whole defect and in the left parietal bone the barrier of PTFE was positioned in the floor and externally to the surgical defect. After 7, 14, 30 and 45 days four animals were sacrificed in each period and the bone containing the defects were submitted to the microscopic analysis. The results of the study revealed that the PTFE barrier was more effective for bone regeneration in shallow transcortical defects compared to the calcium sulfate. However, additional experiments are necessary to determine if calcium sulfate would be successful in other bone defects types or the use of the material under another consistence could complement the results obtained in this work.

Dental fluorosis: Exposure, prevention and management

Dental fluorosis is a developmental disturbance of dental enamel, caused by successive exposures to high concentrations of fluoride during tooth development, leading to enamel with lower mineral content and increased porosity. The severity of dental fluorosis depends on when and for how long the overexposure to fluoride occurs, the individual response, weight, degree of physical activity, nutritional factors and bone growth. The risk period for esthetic changes in permanent teeth is between 20 and 30 months of age. The recommended level for daily fluoride intake is 0.05 - 0.07 mg F/Kg/day, which is considered of great help in preventing dental caries, acting in remineralization. A daily intake above this safe level leads to an increased risk of dental fluorosis. Currently recommended procedures for diagnosis of fluorosis should discriminate between symmetrical and asymmetrical and/or discrete patterns of opaque defects. Fluorosis can be prevented by having an adequate knowledge of the fluoride sources, knowing how to manage this issue and therefore, avoid overexposure.

Inferior alveolar nerve transposition with involvement of the mental foramen for implant placement

Inferior Alveolar Nerve (IAN) transposition is an option for prosthetic rehabilitation in cases of moderate or even severe bone reabsorption for patients that do not tolerate removable dentures. The aim of the present report is to describe an inferior alveolar nerve transposition with involvement of the mental foramen for implant placement. The surgical procedure was performed under local anesthesia, by the inferior alveolar, lingual and buccal nerve blocking technique. Centripetal osteotomy was performed, and bone tissue was removed, leaving the nerve tissue free in the foramen area. After that, transsection of the incisor nerve was performed, and lateral osteotomy was started from the buccal direction, toward the trajectory of the IAN. The procedure was concluded, by making use of a delicate resin spatula to manipulate the vascular-nervous bundle. The drilling sequence for placing the dental implants was performed, and autogenous bone was harvested using a bone collector attached to the surgical suction appliance. After the implants were placed, the bone tissue previously collected during the osteotomies and drilling processes was placed in order to protect the IAN from contact with the implants. The surgical protocol for inferior alveolar nerve transposition, followed by implant placement presented excellent results, with complete recovery of the sensitivity, seven months after the surgical procedure.

Importance of cone beam computed tomography for diagnosis of calcifying cystic odontogenic tumor associated to odontoma. Report of a case

The calcifying cystic odontogenic tumour (CCOT) is a rare benign cystic neoplasm not infrequently associated with odontoma. This report documents a case of CCOT associated with compound odontoma arising in the anterior maxilla in a 25-year-old woman. Conventional radiographs showed a large calcified mass with poorly visualized radiolucent margins. The extent and condition of the internal structure of the CCOT associated with odontoma was able to be determined based on radiographic findings from cone beam computed tomography. This advanced image technique proved to be extremely useful in the radiographic assessment of this particular neoplasm of the jawbones.

Microbial leakage of MTA, Portland cement, Sealapex and zinc oxide-eugenol as root-end filling materials

Objective: The aim of this study was to compare the microbial leakage of mineral trioxide aggregate (MTA), Portland cement (PC), Sealapex and zinc oxide-eugenol (ZOE) as root-end filling materials.Study design: An in vitro microbial leakage test (MLT) with a split chamber was used in this study. A mixture of facultative bacteria and one yeast (S. aureus + E. faecalis + P. aeruginosa + B. subtilis + C. albicans) was placed in the upper chamber and it could only reach the lower chamber containing Brain Heart Infusion broth by way of leakage through the root-end filling. Microbial leakage was observed daily for 60 days. Sixty maxillary anterior human teeth were randomly assigned to different groups - MTA and PC (gray and white), Sealapex + zinc oxide and ZOE, control groups and subgroups to evaluate the influence of EDTA for smear layer removal. These materials were further evaluated by an agar diffusion test (ADT) to verify their antimicrobial efficacy. Data were analyzed statistically by Kruskal-Wallis and Mann-Whitney test.Results: In the MLT, Sealapex + zinc oxide and ZOE did not show evidence of microbial leakage over the 60-day experimental period. The other materials showed leakage from the 15th day. The presence of smear layer influenced microbial leakage. Microbial inhibition zones were not observed in all samples tested by ADT.Conclusion: Sealapex + zinc oxide and ZOE did not show microbial leakage over the experimental period, whereas it was verified within 15 to 45 days in MTA and Portland cement.

Citotoxicidade da Punica granatum L. (romã) sobre cultura de fibroblastos e de células de linhagem cancerígena

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nas dobras da memória oficial: cidade, imagem e história na voz de rezadeiras de Capanema-PA

Em Capanema, no nordeste do Pará, mulheres rezadeiras, motivadas por fotografias, tecem narrativas históricas desvelando trajetórias de migrantes nordestinos para o município, elaborando representações do conflituoso cotidiano da vida urbana. Por meio de sensibilidades urdidas em simbiose de corpo, voz e imagens, as narradoras produzem práticas de leitura que permitem questionar a escrita convencional da história local, consagrada nos jogos mentais de centenas de moradores. Este artigo, portanto, seguindo a metodologia da História Oral e dialogando com intelectuais dos Estudos Culturais e Antropologia da Religião, ao cruzar a leitura de imagens oficiais com a interpretação dada pelas rezadeiras sobre tramas e dramas da urbe, numa perspectiva "vista de baixo" e popular, esgarça imaginários cristalizados, trazendo para a escrita da história outras experiências e paisagens culturais comumente postas nas dobras de retratos emoldurados pelo discurso do poder hegemônico.