Niterói, Brazil


Niterói, Brazil
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Li G.-H.,Fuzhou Dongfang Hospital | Niu L.-N.,PLA Fourth Military Medical University | Zhang W.,Huazhong University of Science and Technology | Olsen M.,North Shore Endodontics | And 5 more authors.
Acta Biomaterialia | Year: 2014

New obturation biomaterials have been introduced over the past decade to improve the seal of the root canal system. However, it is not clear whether they have really produced a three-dimensional impervious seal that is important for reducing diseases associated with root canal treatment. A review of the literature was performed to identify models that have been employed for evaluating the seal of the root canal system. In vitro and in vivo models are not totally adept at quantifying the seal of root canals obturated with classic materials. Thus, one has to resort to clinical outcomes to examine whether there are real benefits associated with the use of recently introduced materials for obturating root canals. However, there is no simple answer because endodontic treatment outcomes are influenced by a host of other predictors that are more likely to take precedence over the influence of obturation materials. From the perspective of clinical performance, classic root filling materials have stood the test of time. Because many of the recently introduced materials are so new, there is not enough evidence yet to support their ability to improve clinical performance. This emphasizes the need to translate anecdotal information into clinically relevant research data on new biomaterials. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Versiani M.A.,University of Sao Paulo | Leoni G.B.,University of Sao Paulo | Steier L.,University of Warwick | De-Deus G.,Unigranrio | And 3 more authors.
Journal of Endodontics | Year: 2013

Introduction: The newly developed single-file systems claimed to be able to prepare the root canal space with only 1 instrument. The present study was designed to test the null hypothesis that there is no significant difference in the preparation of oval-shaped root canals using single- or multiple-file systems. Methods: Seventy-two single-rooted mandibular canines were matched based on similar morphologic dimensions of the root canal achieved in a micro-computed tomographic evaluation and assigned to 1 of 4 experimental groups (n = 18) according to the preparation technique (ie, Self-Adjusting File [ReDent-Nova, Ra'anana, Israel], WaveOne [Dentsply Maillefer, Ballaigues, Switzerland], Reciproc [VDW, Munich, Germany], and ProTaper Universal [Dentsply Maillefer] systems). Changes in the 2- and 3-dimensional geometric parameters were compared with preoperative values using analysis of variance and the post hoc Tukey test between groups and the paired sample t test within groups (α = 0.05). Results: Preparation significantly increased the analyzed parameters; the outline of the canals was larger and showed a smooth taper in all groups. Untouched areas occurred mainly on the lingual side of the middle third of the canal. Overall, a comparison between groups revealed that SAF presented the lowest, whereas WaveOne and ProTaper Universal showed the highest mean increase in most of the analyzed parameters (P <.05). Conclusions: All systems performed similarly in terms of the amount of touched dentin walls. Neither technique was capable of completely preparing the oval-shaped root canals. © 2013 American Association of Endodontists.

Lamas C.D.C.,Instituto Nacional Of Cardiologia | Ramos R.G.,Instituto Nacional Of Cardiologia | Lopes G.Q.,Unigranrio | Santos M.S.,Instituto Nacional Of Cardiologia | And 6 more authors.
International Journal of Infectious Diseases | Year: 2013

PCR was used to detect Coxiella burnetii and Bartonella spp in heart valves obtained during the period 1998-2009 from patients operated on for blood culture-negative endocarditis in a cardiac surgery hospital in Brazil. Of the 51 valves tested, 10 were PCR-positive; two were positive for Bartonella and one for C. burnetii. © 2012 International Society for Infectious Diseases.

Jimbo R.,Malmö University | Tovar N.,New York University | Marin C.,UNIGRANRIO | Teixeira H.S.,New York University | And 5 more authors.
International Journal of Oral and Maxillofacial Surgery | Year: 2014

Information concerning the effects of the implant cutting flute design on initial stability and its influence on osseointegration in vivo is limited. This study evaluated the early effects of implants with a specific cutting flute design placed in the sheep mandible. Forty-eight dental implants with two different macro-geometries (24 with a specific cutting flute design - Blossom group; 24 with a self-tapping design - DT group) were inserted into the mandibular bodies of six sheep; the maximum insertion torque was recorded. Samples were retrieved and processed for histomorphometric analysis after 3 and 6 weeks. The mean insertion torque was lower for Blossom implants (P < 0.001). No differences in histomorphometric results were observed between the groups. At 3 weeks, P = 0.58 for bone-to-implant contact (BIC) and P = 0.52 for bone area fraction occupied (BAFO); at 6 weeks, P = 0.55 for BIC and P = 0.45 for BAFO. While no histomorphometric differences were observed, ground sections showed different healing patterns between the implants, with better peri-implant bone organization around those with the specific cutting flute design (Blossom group). Implants with the modified cutting flute design had a significantly reduced insertion torque compared to the DT implants with a traditional cutting thread, and resulted in a different healing pattern. © 2014 International Association of Oral and Maxillofacial Surgeons.

Jimbo R.,Malmö University | Anchieta R.,New York University | Baldassarri M.,New York University | Marin C.,Federal University of Santa Catarina | And 5 more authors.
Implant Dentistry | Year: 2013

PURPOSE:: Commercial implants differ at macro-, micro-, and nanolevels, which makes it difficult to distinguish their effect on osseointegration. The aim of this study was to evaluate the early integration of 5 commercially available implants (Astra OsseoSpeed, Straumann SLA, Intra-Lock Blossom Ossean, Nobel Active, and OsseoFix) by histomorphometry and nanoindentation. MATERIALS AND METHODS:: Implants were installed in the tibiae of 18 beagle dogs. Samples were retrieved at 1, 3, and 6 weeks (n = 6 for each time point) and were histologically and nanomechanically evaluated. RESULTS:: The results presented that both time (P < 0.01) and implant system and time interaction (P < 0.02) significantly affected the bone-to-implant contact (BIC). At 1 week, the different groups presented statistically different outcomes. No significant changes in BIC were noted thereafter. There were no significant differences in rank elastic modulus (E) or in rank hardness (H) for time (E: P > 0.80; H: P > 0.75) or implant system (E: P > 0.90; H: P > 0.85). CONCLUSIONS:: The effect of different implant designs on osseointegration was evident especially at early stages of bone healing. Copyright © 2013 by Lippincott Williams & Wilkins.

Menezes B.C.,Petrobras | Menezes B.C.,Federal University of Rio de Janeiro | Moro L.F.L.,Petrobras | Lin W.O.,Unigranrio | And 2 more authors.
Industrial and Engineering Chemistry Research | Year: 2014

The oil industry in Brazil has accounted for US$300 billion in investments over the past 10 years, and further expansions are planned to supply the needs of the future fuel market in terms of both quantity and quality. In this paper we analyze the Brazilian fuel production and market scenarios considering the country's planned investments to prevent a fuel deficit of around 30% in 2020. A nonlinear programming model is proposed to predict the national overall capacity for different oil-refinery units considering four future market scenarios. Single-period operational planning cases for the present and intermediate scenarios and those considered in 2020 are proposed by changing demands, costumer preference, and planned investments to calculate fuel production and import figures for the current and future production and market scenarios in the country. The results indicate a different processing outline in the national overall unit capacity planning. © 2014 American Chemical Society.

De-Deus G.,UNIGRANRIO | Reis C.,UNIGRANRIO | Paciornik S.,Pontifical Catholic University of Rio de Janeiro
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology | Year: 2011

The smear layer phenomenon has been extensively addressed over the past 3 decades. However, there still are unanswered questions on this issue and the main responsible factor is the qualitative and nonreproducible character of most in vitro smear layer removal studies. The methodological reasons that led to the current lack of reliable conclusions on procedures aiming to remove the smear layer are comprehensively addressed. The limitations and outcomes related to different assessment methods are discussed as well. General speaking, the results by score-based conventional SEM studies are not trustworthy and reproducible. Computational routines able to automatically extract quantitative data of dentin morphology are necessary to minimize the human bias. An ideal experimental model should have a longitudinal observational character, in which a given dentin area can be observed at different times. The use of flat dentin samples should be avoided because of the influence of gravity as well as root canal anatomy on the final result of the chelating process. The experimental model also needs to take into consideration the amount and distribution of sclerotic dentin and irregular secondary dentin, otherwise the final results can be compromised. Inasmuch as there is a clear lack of scientific standard, simple comparative SEM evaluations are pointless at the present moment. The ideal experimental model to assess smear layer removal is not currently available. Therefore, further research efforts should be directed to the development of and testing of new methodological approaches to be used in the smear layer removal studies. The improvement of the experimental models is a requirement to draw up optimized clinical guidelines for the chemical treatment of the root dentin. © 2011 Mosby, Inc. All rights reserved.

Dalbem M.C.,Unigranrio | Brandao L.E.T.,Pontifical Catholic University of Rio de Janeiro | Gomes L.L.,Pontifical Catholic University of Rio de Janeiro
Energy Policy | Year: 2014

Wind energy has been negotiated in Brazil's regulated market through auctions organized by the government. Bilateral negotiations in the free market have been scarce. In 2011 wind farms were allowed to bid in '. A minus 5 (A-5)' auctions, for energy with first delivery date 5 years ahead. This new design was expected to stimulate negotiations in the free market, as the 20-year contract in the regulated market eases financing while the 5-year grace period grants wind farms the option to sell whatever energy is generated beforehand in the free market. We modeled bidders' price decision in A-5 auctions as Real Options and concluded that given the low prices averaging USD 50/MW. h, winners are tempted to defer investment, expecting more favorable equipment and energy prices, or a better knowledge of the wind site. Construction is likely to begin in 2-3 years, with little time left for the free market. Bidders that consider the option of eventually abandoning the project are more price competitive, increasing chances that some wind farms will never materialize. Therefore, this attempt to foster the free market may not pay-off and, moreover, it may have the unfavorable effect of turning Brazil's energy expansion planning a more difficult task. © 2013 Elsevier Ltd.

Baldassarri M.,New York University | Bonfante E.,UNIGRANRIO | Suzuki M.,Tufts University | Marin C.,UNIGRANRIO | And 3 more authors.
Journal of Biomedical Materials Research - Part B Applied Biomaterials | Year: 2012

Bone remodeling, along with tissue biomechanics, is critical for the clinical success of endosseous implants. This study evaluated the long-term evolution of the elastic modulus (GPa) and hardness (GPa) of cortical bone around human retrieved plateau root form implants. Thirty implant-in-bone specimens showing no clinical failure were retrieved from patients at different in-vivo times (0.3 to ∼24 years) due to retreatment needs. After dehydration, specimens were embedded in methacrylate-based resin, sectioned along the bucco-lingual long axis and fixed to acrylic plates and nondecalcified processed to slides with ∼50 μm in thickness. Nanoindentation testing was carried out under wet conditions on bone areas within the first three plateaus. Indentations (n = 120 per implant total) were performed with a maximum load of 300 μN (loading rate: 60 μN/s) followed by a holding and unloading time of 10 s and 2 s, respectively. Elastic modulus (E, GPa) and hardness (H, GPa) were computed. Both E and H values presented increased values as time in vivo elapsed (E: r = 0.84; H: r = 0.78). Significantly higher values for E and H were found after 5 years in vivo (p < 0.001). Maxillary or mandibulary arches or positioning did not affect mechanical properties, nor did implant surface treatment on the long-term bone biomechanical response (E: p ≥ 0.09; H: p ≥ 0.3). This work suggests that human cortical bone around plateau root form implants presents an increase in elastic modulus and hardness during the first 5 years following implantation and presents stable mechanical properties thereafter. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012. Copyright © 2012 Wiley Periodicals, Inc.

Jimbo R.,Malmö University | Tovar N.,New York University | Anchieta R.B.,New York University | MacHado L.S.,New York University | And 3 more authors.
International Journal of Oral and Maxillofacial Surgery | Year: 2014

This study investigated the effect of undersized preparations with two different implant macrogeometries. There were four experimental groups: group 1, conical implant with an undersized osteotomy of 3.2mm; group 2, conical implant with an undersized osteotomy of 3.5mm; group 3, cylindrical implant with an undersized osteotomy of 3.2mm; group 4, cylindrical implant with an undersized osteotomy of 3.5mm. Implants were placed in one side of the sheep mandible (n =6). After 3 weeks, the same procedure was conducted on the other side; 3 weeks later, euthanasia was performed. All implants were 4mm×10mm. Insertion torque was recorded for all implants during implantation. Retrieved samples were subjected to histological sectioning and histomorphometry. Implants of groups 1 and 2 presented significantly higher insertion torque than those of groups 3 and 4 (P <0.001). No differences in bone-to-implant contact or bone area fraction occupied were observed between the groups at 3 weeks (P >0.24, and P >0.25, respectively), whereas significant differences were observed at 6 weeks between groups 1 and 2, and between groups 3 and 4 (P <0.01). Undersized drilling affected the biological establishment of bone formation around both dental implant macrogeometries. © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

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