ABSTRACT Objective: To evaluate the pulp tissue of rat molars after pulpotomies with mineral trioxide aggregate (MTA), BiodentineTM (BDT) and calcium hydroxide (CH) mixed with sterile saline solution (24 hours, 72 hours, 7 days and 15 days), through correlating MPO activity with active neutrophils and MMP8 activity with tissue remodeling. Material and Methods: Thirty-eight Wistar rats were randomly distributed into groups (control, I (MTA gray), II (BDT), and III (CH)) and subdivided according to the study period of 24 hours, 72 hours, 7 days or 15 days after pulpotomy. MMP8 activity was assessed through fluorescence technique, and MPO activity was determined using the MPO assay. Results: A gradual decrease of MPO and MM8 activity occurred in the group MTA over the experimental periods (p<0.05). Groups BDT and CH exhibited an increase in the activity at 7 and 15 days (p<0.05). Conclusion: MTA demonstrated a decrease in the values of MPO e MMP8. BDT and CH showed high neutrophilic and collagenase activity over the experimental periods.

RESUMO Objetivo Avaliar se dois géis clareadores diferentes afetam a microdureza e a rugosidade superficial de corpos de prova de cerâmicafeldspática, in vitro. Métodos um total de 48 discos de porcelana feldspática IPS In Line (Ivoclar-Vivadent) (16 / grupo de tratamento) foram imersos em água destilada (Grupo I, Controle não tratado, ONU), ou tratados com os géis clareadores: Opalescence (15 % peróxido de carbamida; OPA) e Opalescence Xtra Boost (38% peróxido de hidrogênio; OPAXB), por 1h ou 6h diariamente por 14 dias. Medidas de rugosidade superficial (Ra) e microdureza (Knoop, ou KNP) foram regristradas antes e depois do tratamento, e os dados foram submetidos à análise estatística por teste t de Student pareado (P <0,05). Resultados Os tratamentos com Opalescence e Opalescence Xtra Boost não alteraram a rugosidade superficial (p = 0,6199861) ou a microdureza (p = 0,14286744) da porcelana feldspática testada neste estudo. Conclusão Os tratamentos clareadores com Opalescence e Opalescence Xtra Boost podem ser adequados para o tratamento de pacientes submetidos ao tratamento com prótese cerâmica.

ABSTRACT Objective: To evaluate whether two different bleaching gels affect the microhardness and surface roughness of feldspathic ceramic specimens, in vitro. Methods: A total of 48 feldspathic porcelain IPS In Line (Ivoclar-Vivadent) discs (16/treatment group) were immersed in distilled water (Group I, Untreated control, UN), or treated with the bleaching gels: Opalescence (15% carbamide peroxide; OPA) and Opalescence Xtra Boost (38%hydrogen peroxide; OPAXB), for 1h or 6h daily for 14 days. Surface roughness (Ra) and microhardness (Knoop, or KNP) measurements were made before and after treatment, and data were subjected to statistical analysis by paired Student’s t-test (p < 0.05). Results: Treatments using Opalescence and Opalescence Xtra Boost did not altered surface roughness (p=0.6199861) or microhardness (p=0.14286744) of the feldspathic porcelain tested in this study. Conclusion: Bleaching treatments using Opalescence and Opalescence Xtra Boost may be suitable for treatment in patients having ceramic prosthodontic treatment. Conclusion: Bleaching treatments using Opalescence and Opalescence Xtra Boost may be suitable for treatment in patients having ceramic prosthodontic treatment.

Abstract Objectives: To evaluate the effect of calcium hydroxide (CH) associated with two different vehicles as a capping material for pulp tissue in primary molars, compared with mineral trioxide aggregate (MTA). Methodology: Forty-five primary mandibular molars with dental caries were treated by conventional pulpotomy using one of the following materials: MTA only (MTA group), CH with saline (CH+saline group) and CH with polyethylene glycol (CH+PEG group) (15 teeth/group). Clinical and periapical radiographic examinations of the pulpotomized teeth were performed 3, 6, and 12 months after treatment. Data were tested by chi-squared analysis and a multiple comparison post-test. Results: The MTA group showed both clinical and radiographic treatment success in 14/14 teeth (100%), at all follow-up appointments. By clinical evaluation, no teeth in the CH+saline and CH+PEG groups had signs of mobility, fistula, swelling or inflammation of the surrounding gingival tissue. However, in the CH+saline group, radiographic analysis detected internal resorption in up to 9/15 teeth (67%), and inter-radicular bone resorption and furcation radiolucency in up to 5/15 teeth (36%), from 3 to 12 months of follow-up. In the CH+PEG group, 2/11 teeth (18%) had internal resorption and 1/11 teeth (9%) presented bone resorption and furcation radiolucency at all follow-up appointments. Conclusion: CH with PEG performed better than CH with saline as capping material for pulpotomy of primary teeth. However, both combinations yielded clinical and radiographic results inferior to those of MTA alone.

Resumo Introdução Os cimentos resinosos são extensivamente utilizados na fixação de restaurações indiretas de cerâmica e cerômero, sendo classificados em duas categorias: os cimentos resinosos convencionais, que não apresentam uma adesão inerente à estrutura dental e requerem o uso de um sistema adesivo e os cimentos resinosos autoadesivos, que não requerem um tratamento adesivo prévio do substrato dentário. Objetivo Avaliar a resistência de união de dois cimentos resinosos, convencional e autoadesivo, quando utilizados na cimentação de restaurações cerâmicas e ceroméricas, trazendo elementos para propiciar melhor compreensão da interação adesiva em procedimentos de cimentação com as referidas categorias de cimentos resinosos. Material e método Dentes humanos (n=20), cedidos pelo banco de dentes da Universidade Federal de Alfenas (UNIFAL), foram preparados para que cilindros de cerâmica ou de cerômero fossem cimentados utilizando-se dois tipos de cimentos resinosos (autoadesivo e convencional). Após a cimentação, 20 palitos foram obtidos e submetidos ao teste de tração, avaliando-se a força necessária para a fratura. Os valores obtidos foram submetidos à análise estatística empregando-se a análise de variância (ANOVA) e o teste de Tukey. Resultado As forças mínimas e máximas necessárias ao rompimento do cimento convencional foram superiores às mesmas requeridas para o rompimento da união promovida pelo cimento autoadesivo, bem como as medianas e as médias aritméticas, independentemente do material restaurador empregado. O teste de Tukey demonstrou que as diferenças entre os cimentos empregados são estatisticamente significantes, independentemente do material restaurador. Conclusão Os resultados deste trabalho sugerem que o material utilizado para a confecção dos corpos de prova (cerâmica ou cerômero) não influenciou na resistência à tração, sendo que o cimento convencional apresentou valores superiores de resistência.

Abstract Introduction Resin cements are extensively used in the fixation of indirect restorations of ceramics and ceramics, divided into two categories: conventional resin cements, which do not present an inherent adhesion to the dental structure and require the use of an adhesive system, and the self-adhesive resin cements, which do not require a prior adhesive treatment of the dental substrate. Objective: To evaluate the microtensile bond strength of two resin-based cements, conventional and self-adhesive, according to required operating protocols, when luting ceramic and indirect composite restorations. Material and method Human molars (n=20) donated by UNIFAL teeth bank were prepared and, after being divided into two groups, ceramic or composite cylinders were luted to them with two resin-based cements (conventional and self-adhesive). Prepared teeth were sectioned vertically in both buccal-lingual and mesio-distal directions, to obtain 8 mm high, square-shaped “sticks” that were subject to microtensile bond strength test, and the necessary force to fracture them was evaluated. Results were subject to two-way ANOVA and Tukey test. Result Minimum and maximum forces to disrupt conventional cement were greater than the required one for self-adhesive cement, as well as mean bond strength, despíte of the restorative material. Tukey test showed that diferences were statistically significant, regardless the restorative material. Conclusion Restorative materials did not influence microtensile bond strength values, with no statistically significant differences. The difference between microtensile bond strength values of resin cements tested was statistically significant.

RESUMO Objetivo: Avaliar a microdureza de corpos de prova das resinas acrílicas VipiCril® (resina termopolimerizável) e Bosworth New Truliner®(resina autopolimerizável), antes e após, a imersão em soluções de digluconato de clorexidine a 0,12 %, hipoclorito de sódio a 1%, Corega Tabs® e água (controle), testando a hipótese nula de que os enxaguatórios bucais e substâncias químicas utilizadas na desinfecção de próteses totais não interferem na microdureza superficial, podendo assim, serem utilizados como coadjuvantes na higiene bucal de pacientes desdentados. Métodos: Foram confeccionados 60 corpos de prova da resina VipiCril®(termopolimerizável) e 60 corpos de prova da resina Bosworth New Truliner® (autopolimerizável) com 16mm de diâmetro por 6mm de altura, estes foram divididos randomicamente em quatro grupos de 15 amostras cada, sendo submetidos a testes de microdureza Knoop (KHN), antes e após, ciclos de imersões em soluções de digluconato de clorexidine a 0,12%, hipoclorito de sódio a 1%, Corega Tabs® e água (controle). Resultados: Os corpos de prova de resina VipiCril e Bosworth imersos nas soluções de clorexidine a 0,12%, Corega Tabs®e água apresentaram diminuição de microdureza. Conclusão: A solução de hipoclorito de sódio a 1% causou menor dano à estrutura da prótese não causando diminuição da microdureza superficial.

ABSTRACT Objective: To evaluate the microhardness of specimens of acrylic resins VipiCril® (thermally polymerized resin) and Bosworth New Truliner® (self-polymerized resin), before and after immersion in solutions of 0.12% chlorhexidine digluconate, 1% sodium hypochlorite, Corega Tabs® and water (control), testing the null hypothesis that the mouthwashes and chemicals used to disinfect complete dentures do not interfere with the superficial microhardness, and can therefore be used as adjuncts to oral hygiene of edentulous patients. Methods: Sixty specimens of resin VipiCril®(thermally polymerized resin) and 60 specimens of resin Bosworth New Truliner® (self-polymerized resin) measuring 16 mm of diameter and 6 mm of height were prepared, which were randomly divided into four groups of 15 specimens each, undergoing Knoop hardness tests (KHN) both before and after cycles of immersion in solutions of 0.12% chlorhexidine digluconate, 1% sodium hypochlorite, Corega Tabs® and water (control). Results: The specimens of resins VipiCril and Bosworth immersed in solutions of 0.12% chlorhexidine, Corega Tabs® and water showed decreased microhardness. Conclusion: The 1% sodium hypochlorite solution caused least damage to the denture structure, not leading to decrease of the superficial microhardness.

ABSTRACT Because many mechanical variables are present in the oral cavity, the proper load transfer between the prosthesis and the bone is important for treatment planning and for the longevity of the implant-supported fixed partial denture. Objectives To verify the stress generated on the peri-implant area of cantilevered implant-supported fixed partial dentures and the potential effects of such variable. Material and Methods A U-shaped polyurethane model simulating the mandibular bone containing two implants (Ø 3.75 mm) was used. Six groups were formed according to the alloy’s framework (CoCr or PdAg) and the point of load application (5 mm, 10 mm and 15 mm of cantilever arm). A 300 N load was applied in pre-determined reference points. The tension generated on the mesial, lingual, distal and buccal sides of the peri-implant regions was assessed using strain gauges. Results Two-way ANOVA and Tukey statistical tests were applied showing significant differences (p<0.05) between the groups. Pearson correlation test (p<0.05) was applied showing positive correlations between the increase of the cantilever arm and the deformation of the peri-implant area. Conclusions This report demonstrated the CoCr alloy shows larger compression values compared to the PdAg alloy for the same distances of cantilever. The point of load application influences the deformation on the peri-implant area, increasing in accordance with the increase of the lever arm.

OBJECTIVES: The complexity and heterogeneity of human bone, as well as ethical issues, frequently hinder the development of clinical trials. The purpose of this in vitro study was to determine the modulus of elasticity of a polyurethane isotropic experimental model via tension tests, comparing the results to those reported in the literature for mandibular bone, in order to validate the use of such a model in lieu of mandibular bone in biomechanical studies. MATERIAL AND METHODS: Forty-five polyurethane test specimens were divided into 3 groups of 15 specimens each, according to the ratio (A/B) of polyurethane reagents (PU-1: 1/0.5, PU-2: 1/1, PU-3: 1/1.5). RESULTS: Tension tests were performed in each experimental group and the modulus of elasticity values found were 192.98 MPa (SD=57.20) for PU-1, 347.90 MPa (SD=109.54) for PU-2 and 304.64 MPa (SD=25.48) for PU-3. CONCLUSION: The concentration of choice for building the experimental model was 1/1.

OBJECTIVES: The complexity and heterogeneity of human bone, as well as ethical issues, most always hinder the performance of clinical trials. Thus, in vitro studies become an important source of information for the understanding of biomechanical events on implant-supported prostheses, although study results cannot be considered reliable unless validation studies are conducted. The purpose of this work was to validate an artificial experimental model based on its modulus of elasticity, to simulate the performance of human bone in vivo in biomechanical studies of implant-supported prostheses. MATERIAL AND METHODS: In this study, fast-curing polyurethane (F16 polyurethane, Axson) was used to build 40 specimens that were divided into five groups. The following reagent ratios (part A/part B) were used: Group A (0.5/1.0), Group B (0.8/1.0), Group C (1.0/1.0), Group D (1.2/1.0), and Group E (1.5/1.0). A universal testing machine (Kratos model K - 2000 MP) was used to measure modulus of elasticity values by compression. RESULTS: Mean modulus of elasticity values were: Group A - 389.72 MPa, Group B - 529.19 MPa, Group C - 571.11 MPa, Group D - 470.35 MPa, Group E - 437.36 MPa. CONCLUSION: The best mechanical characteristics and modulus of elasticity value comparable to that of human trabecular bone were obtained when A/B ratio was 1:1.

Cyanocrylates have been widely used in the medical and dental fields for several years. In Dentistry, cyanoacrylates have been used for suturing, pulp capping, as retrofilling material in endodontic surgeries, and as cervical plug for pulpless teeth bleaching. The biocompatibility of these adhesives has been the topic of many researches and subcutaneous implantation is an effective methodology for these studies. The present study evaluated the biocompatibility of three different cyanoacrylate-based adhesives. Thirty-six Wistar rats were used, divided into four groups of 9 animals each: A (control) - distilled water, B - cyanoacrylate ester (Super Bonder), C - n-butyl-cyanoacrylate (Histoacryl) and D - alpha-cyanoacrylate (Three Bond). The materials were dispensed in sponges of polyvinyl chloride, the animals were incised and the sponges were inserted in the subcutaneous tissue and sutured. Each group was sub-divided according to the time of sacrifice of the animals: 7, 21 and 45 days. Subjective analysis of the histologic material showed that all groups presented some degree of irritability, but the inflammatory reaction decreased with the experimental time in all groups. Group D showed an inflammatory reaction which was closer to that of the control group and was considered to have good biocompatibility. Groups B and C were similar and presented more aggressive inflammatory reactions when compared to the control group. Based on the results, it was concluded that alpha-cyanoacrylate (Three Bond) was the most biocompatible adhesive because it caused the lowest levels of inflammation.