Does the combination of whitening toothpaste and hydrogen peroxide bleaching increase the surface roughness and change the morphology of a nanofilled composite?

Aim: To evaluate changes in the surface roughness and morphology of a nanofilled composite following toothbrushing with a whitening (WT) or regular toothpaste (RT), alone or combined with 35% hydrogen peroxide bleaching (HP). Methods: Seventy disc-shaped nanofilled composite (Filtek Z350XT) specimens were randomly divided into groups (n=10): WT, RT, TB (without toothpaste ­ control) or the combinations WT/ HP, RT/HP, TB/HP and HP. All groups underwent toothbrushing simulation (60,000 cycles) and bleaching treatment (4 sessions). Mean surface roughness (Ra, µm) was measured before (T0) and after treatments (TB). Surface morphology was assessed by scanning electron microscopy (SEM) at TB. Mean Ra was analyzed using general mixed models and multiple comparisons by the Tukey-Kramer test (α=5%). Results: HP caused no surface roughness changes on the nanofilled composite after treatment (p>0.05). RT toothbrushing, combined or not with HP, increased the surface roughness (p<0.05). WT and WT/ HP protocols had no effect on the surface roughness of the composite (p>0.05). The nanofilled composite submitted to RT toothbrushing combined with HP (RT/HP) presented substantial surface alterations under SEM, showing deep depressions and round-shaped defects. Toothbrushing with RT combined with the bleaching agent increased exposure of the inorganic fillers. Conclusion: WT toothbrushing, regardless of HP combination, or the single HP protocol had no effect on the surface roughness of the nanofilled composite. However, RT combined with HP negatively affected surface roughness and presented the most noticeable surface changes among groups

Use of scanning electron microscope to evaluate the marginal fit of protocol bars obtained through benchtop or intraoral digital scanners

Aim: To evaluate the marginal fit of protocol bars milled from digital models obtained by conventional molding followed by bench scanning or digital molding with an intraoral scanner. Methods: Four morse-cone implants and the mini-pillars were installed in a 3D printed mandible model (master model). Digital models of the master model were obtained by (n=10): (Group A - Conventional) conventional (analog) molding of the master model followed by bench scanning or (Group B - Digital) molding of the master model with an intraoral scanner. All-on-four protocol bars were designed and milled from the digital models for both groups and screwed into the master model. Scanning electron microscopy (SEM) images from the distal, central, and mesial regions of each implant were obtained and the implant-protocol bar marginal fit was measured in an image software (Image J). The mean misfit of each region was analyzed by two-factor ANOVA, Tukey test, and Student's t-test (0,05 = 0.05). Results: The digital approach (B) showed higher misadaptation than the conventional approach (A, p < 0.05), regardless of the region evaluated. In group A, the central region showed higher maladjustment than the mesial region (p<0.05), however, there were no differences among regions of group B (p>0.05). Conclusion: The conventional method of acquiring digital models using the bench scanner produced bars for the All-On-Four protocol with better marginal fit than the digital models obtained with an intraoral scanner

Effects of black tea tooth staining previously to 35% hydrogen peroxide bleaching

Aim: To determine if the artificial staining with black tea (BT) influences the enamel microhardness before in-office bleaching and if BT staining is necessary to evaluate the efficacy of bleaching with 35% hydrogen peroxide Methods: Enamel/dentin blocks were randomized into groups according to the staining protocol (n=5/group): (CO) control ­ maintained in artificial saliva solution (AS); (BT4) immersed in black tea solution for 4 h; (BT24) immersed in black tea solution for 24 h. After the staining protocols, all specimens were kept in AS for one week, followed by bleaching (three sessions of HP application for 40 min). Knoop surface microhardness (kgF/mm2) was determined at baseline (T0), after staining (T1), after 7 days of storage in AS (T2), and after bleaching (T3). The color (∆E00) and coordinate changes (∆L, ∆a, ∆b) were measured using a digital spectrophotometer at T0 and T3. Data were submitted to one-way (∆E00, ∆L, ∆a, ∆b) or two-way ANOVA repeated measures (kgF/mm2) and Tukey's test (a=5%). Results: The staining protocols (BT4 and BT24) promoted significantly lower microhardness (T1 and T2, p<0.05) than CO, whereas CO was the only group to maintain microhardness values over time. Bleaching promoted perceptible ∆E00 without a significant difference among the groups regardless of the staining protocol (p=0.122). CO and BT4 showed no differences in terms of ∆L and ∆a (p>0.05), but BT4 displayed a higher ∆b than CO. Conclusion:The artificial staining with BT negatively affected the enamel surface microhardness and was not essential to evaluate the efficacy of 35% hydrogen peroxide bleaching

Bond strength of resin composite to enamel submitted to at-home desensitizer and bleaching agents

Aim: This study evaluated the effect of a desensitizer agent (DES) during bleaching with 10% carbamide peroxide (CP) on enamel microshear bond strength (µSBS). Methods: Sixty bovine incisors were obtained and randomly distributed into groups (n=15): (C) Control: no desensitizing or bleaching, (DES) desensitizing gel application, (CP) bleaching with 10% CP and (CP/DES) bleaching with 10% CP combined with DES. Bleaching was performed for 6 h/day for 14 consecutive days. DES was applied for 8 h only on the 7th and 14th days of therapy. Specimens were stored in artificial saliva among the CP or DES applications and submitted to µSBS testing at three postrestoration times (n=5): 24 h, 7 days, and 14 days after bleaching using a universal testing machine. Failure modes were observed under a stereomicroscope. Data were analyzed by two-way ANOVA and Tukey's test (α=5%). Results: Immediately after bleaching (24 h), CP promoted lower µSBS than the C and DES groups (p<0.05) but with no differences from the CP/DES. µSBS increased in the DES, CP, and CP/DES groups (p<0.05) when bonding was performed for 7 or 14 days elapsed from bleaching. CP/DES exhibited the highest µSBS among the groups 14 days after bleaching (p<0.05). Cohesive failure in enamel was predominant in the CP groups, while adhesive failure was mostly observed for the other groups. Conclusion: The use of a desensitizer during at-home bleaching maintained the enamel immediate bond strength, and its application favored bonding when the restoration was delayed for 14 days

Combination of at-home and in-office bleaching techniques: case series / Combinação das técnicas de clareamento dental caseira e de consultório: relato de casos

ABSTRACT Tooth bleaching is one of the most conservative aesthetic techniques. At-home and in-office bleaching may be performed, as well as the combination of both techniques. As this combination may be done in different manners, distinct orders of combinations were proposed in this report. A 24 years-old man, whose upper central incisor and canine shades were A2 and A3 respectively, was initially treated by chair-side with 40-min application of 40% hydrogen peroxide (HP) for two sessions. Afterwards, an two-week overnight at-home bleaching was performed with 10% carbamide peroxide (CP). The shade of upper central incisors changed to 1M1 and canine was B1. Conversely, a 30 years-old woman was firstly conducted with at-home bleaching (overnight 4-weeks 10% CP) and, subsequently, with a single appointment of in-office bleaching for 45 minutes (35% HP). The shade of her upper central incisor changed from A1 to 0.5M1 and the upper canine from A3 to B1. The VITA classical (A1-D4) shade guide and VITA Bleached guide 3D-MASTER were used to determine the tooth color during the treatments. In both bleaching treatments, patients reported no significant tooth sensitivity and the final outcomes met their expectation.

RESUMO O clareamento dental é uma das técnicas estéticas mais conservadoras no âmbito odontológico. Técnicas de clareamento caseira ou de consultório, ou a combinação de ambas, podem ser realizadas para alcançar o prognóstico desejado. Esta combinação das técnicas pode ser realizada por meio de diferentes abordagens, como apresentado neste relato de casos. Um paciente do gênero masculino, 24 anos de idade, cujos incisivo central superior e caninos apresentaram cor A2 e A3, respectivamente, foi inicialmente submetido à técnica de clareamento de consultório de duração por sessão de 40 mim com gel de peróxido de hidrogênio (PH) 40%, em duas sessões. Posteriormente, a técnica de clareamento caseira foi realizada durante duas semanas com gel de peróxido de carbamida (PC) a uma concentração de 10%.A cor final dos incisivos centrais superiores foi alterada para 1M1, enquanto a dos caninos para B1. Por outro lado, uma paciente do gênero feminino, 30 anos de idade, foi inicialmente submetida ao clareamento caseiro (durante a noite, por 4 semanas- PC 10%), e subsequentemente, com aplicação pontual de agente clareador (PH 35%) em consultório, em sessão de 45 min. A cor do incisivo central superior da paciente, mudou de A1 para 0,5M1 e do canino superior de A3 para B1. As escalas de cor VITA Classic (A1-D4), e VITA Bleachedguided 3D-MASTER foram utilizadas nesta série de casos para determinar a coloração dos dentes durante os tratamentos. Em ambos os tratamentos, os pacientes não reportaram sensibilidade dental significante, e suas expectativas finais foram atendidas.

Three-year follow-up of flowable bulk-fill resin restorations in posterior teeth: a double-blind randomized controlled clinical trial / Acompanhamento de três anos de restaurações do tipo bulk-fill flow em dentes posteriores: ensaio clínico controlado randomizado duplo-cego

Objetivo: Este ensaio clínico randomizado avaliou o comportamento de restaurações com resina composta bulk-fill flow em dentes posteriores após três anos do tratamento restaurador. Métodos: Dezessete pacientes (12 mulheres, 5 homens, idade 23-59) foram selecionados para ter pelo menos duas restaurações de amálgama ou de resina composta substituídas, ou receber tratamento restaurador para lesão cariosa. As cavidades foram aleatoriamente alocadas para receberem o compósito bulk-fill flow Suferil SDR Flow, oclusamente coberto por uma resina composta convencional nano-híbrida Esthet-X HD (técnica bulk and body), ou serem preenchidas exclusivamente com Esthet-X HD, inseridas em incrementos de 2mm cada técnica incremental). Um adesivo convencional de dois passos foi aplicado em todas as cavidades. Trinta e quatro restaurações Classes I ou II foram realizados em dentes posteriores (n=17) no início do estudo (baseline). Após 03 anos, os critérios do USPHS modificado e FDI foram utilizados para avaliar as restaurações. Os dados foram submetidos à análise estatística Mann-Whitney (p<0,05). Resultados: No acompanhamento de 3 anos, vinte e quatro restaurações (17 Classes I e 7 Classes II) foram avaliadas. Não foram detectadas diferenças entre as técnicas restauradoras (p>0,05). Não houve falha em nenhuma restauração ao longo do tempo. Conclusão: Após 03 anos de serviço clínico, todas restaurações utilizando um compósito bulk-fill flow em dentes posteriores demonstraram uma performance satisfatória. Significância Clínica: A qualidade geral das restaurações em dentes posteriores realizadas com a técnica bulk and body foi similar ao das restaurações incrementais utilizando um compósito nano-híbrido. (AU)

Objective: This randomized clinical trial evaluated the behavior of restorations with flowable bulk-fill resin composite in posterior teeth three years after the restorative treatment. Methods: Seventeen patients (12 women, 5 men, age 23-59) were selected to have at least two failing amalgam or resin restorations replaced and/or to have a carious lesion restored. The cavities were randomly allocated to receive either the flowable bulk-fill composite Surefil SDR Flow occlusally covered with the conventional nano-hybrid composite Esthet-X HD (bulk and body technique) or filled exclusively with Esthet-X HD placed in 2 mm increments (incremental technique). A two-step etch-and-rinse adhesive was applied in all cavities. Thirty-four Class I or II restorations were performed in posterior teeth (n=17) during baseline. After 03 years, modified USPHS and FDI criteria were used to evaluate the restorations. Data were subjected to Mann-Whitney statistical analysis (p<0.05). Results: At the 3-year follow-up, twenty-four restorations (17 Class I and 7 Class II) were evaluated. No diff erences were detected between the bulk and body and the incremental restorations (p>0.05). No restoration failures were observed over time. Conclusion: After 03 years of clinical service, all restorations using a flowable bulk-fill composite in posterior teeth showed an acceptable performance. Clinical Significance: The overall quality of posterior restorations made with the bulk and body technique was similar to that of restorations made with a nano-hybrid composite incrementally placed. (AU)

Effect of violet LED light on in-office bleaching protocols: a randomized controlled clinical trial

Abstract Objective This study evaluated the clinical effect of violet LED light on in-office bleaching used alone or combined with 37% carbamide peroxide (CP) or 35% hydrogen peroxide (HP). Methodology A total of 100 patients were divided into five groups (n=20): LED, LED/CP, CP, LED/HP and HP. Colorimetric evaluation was performed using a spectrophotometer (ΔE, ΔL, Δa, Δb) and a visual shade guide (ΔSGU). Calcium (Ca)/phosphorous (P) ratio was quantified in the enamel microbiopsies. Measurements were performed at baseline (T 0 ), after bleaching (T B ) and in the 14-day follow-up (T 14 ). At each bleaching session, a visual scale determined the absolute risk (AR) and intensity of tooth sensitivity (TS). Data were evaluated by one-way (ΔE, Δa, ΔL, Δb), two-way repeated measures ANOVA (Ca/P ratio), and Tukey post-hoc tests. ΔSGU and TS were evaluated by Kruskal-Wallis and Mann-Whitney, and AR by Chi-Squared tests (a=5%). Results LED produced the lowest ΔE (p<0.05), but LED/HP promoted greater ΔE, ΔSGU and Δb (T 14 ) than HP (p<0.05). No differences were observed in ΔE and ΔSGU for LED/CP and HP groups (p>0.05). ΔL and Δa were not influenced by LED activation. After bleaching, LED/CP exhibited greater Δb than CP (p>0.05), but no differences were found between these groups at T 14 (p>0.05). LED treatment promoted the lowest risk of TS (16%), while HP promoted the highest (94.4%) (p<0.05). No statistical differences of risk of TS were found for CP (44%), LED/CP (61%) and LED/HP (88%) groups (p>0.05). No differences were found in enamel Ca/P ratio among treatments, regardless of evaluation times. Conclusions Violet LED alone produced the lowest bleaching effect, but enhanced HP bleaching results. Patients treated with LED/CP reached the same efficacy of HP, with reduced risk and intensity of tooth sensitivity and none of the bleaching protocols adversely affected enamel mineral content.

Do metal alloy primers increase the bond strength of orthodontic tubes?

Aim: To evaluate the bond strength (BS) and failure mode of orthodontic tubes treated with different alloy primers at the interface among enamel, resin and orthodontic tubes. Methods: Orthodontic tubes were bonded to the enamel of 80 bovine incisors with the orthodontic resin (Transbond XT, 3M Unitek). Prior to bonding, the tubes were chemically treated with (n=20) Metal/Zirconia Primer (MZ, Ivoclar), Scothbond Universal (SB, 3M Espe); Orthoprimer (OP, Morelli) or left untreated (Control - C). Specimens were submitted to 5,000 thermal cycles (5 and 55o C) to age the bonded interface. A shear BS test and failure modes were conducted, and the results were analyzed using one-way analysis of variance and Fisher's exact test, respectively. Results: No differences were observed among groups regardless of the type of alloy primer used (p = 0.254). However, no differences were observed among the failure modes of the groups tested (p=0.694). The adhesive failure mode between the resin and enamel was the most prevalent failure (45%) for groups OP and C, whereas cohesive failure in the orthodontic resin was the most prevalent failure (40%) for groups SB and MZ. Conclusion: Alloy primers were unable to increase the BS of the orthodontic tubes to enamel

Effects of experimental bleaching agents on the mineral content of sound and demineralized enamels

Abstract High concentrations of hydrogen peroxide can cause adverse effects on composition and structure of teeth. However, the addition of calcium and fluoride in bleaching agents may reduce enamel demineralization. Objective: To evaluate chemical changes of sound and demineralized enamels submitted to high concentrations of hydrogen peroxide containing fluoride (F) or calcium (Ca). Material and Methods: Enamel blocks of bovine incisors with standard dimensions were obtained and half of them were submitted to pH-cycling to promote initial enamel caries lesions. Sound and demineralized enamel samples were divided into (n=10): (C) Control (no whitening treatment); (HP) 35% hydrogen peroxide; and two experimental groups: (HPF) 35% HP+0.2% F and (HPC) 35% HP+0.2% Ca. Experimental groups were submitted to two in-office bleaching sessions and agents were applied 3 times for 15 min to each session. The control group was kept in remineralizing solution at 37°C during the bleaching treatment. The surface mineral content of sound and demineralized enamels was determined through Fourier Transform Raman spectroscopy (FT-Raman), Energy dispersive Micro X-ray fluorescence spectroscopy (μ-EDXRF); and the subsurface, through cross-sectional microhardness (CSMH). In addition, polarized light microscopy (PLM) images of enamel subsurface were observed. Results: According to three-way (FT-Raman and μ-EDXRF analyses) or two-way analysis of variance (ANOVA) (CSMH) and Tukey test (α=5%), the calcium or fluoride added to high-concentrated bleaching agents increased phosphate and carbonate concentrations on sound and demineralized enamels (p<0.05). However, HPC and HPF were unable to completely reverse the subsurface mineral loss promoted by bleaching on sound and demineralized enamels. The calcium/ phosphate (Ca/P) ratio of sound enamel decreased after HP treatment (p<0.001). Conclusion: Even though experimental bleaching agents with Ca or F reduced mineral loss for both sound and demineralized enamel surfaces, these agents were unable to reverse the enamel subsurface demineralization.

Influence of fluoride-containing adhesives and bleaching agents on enamel bond strength

This study evaluated the influence of fluoride-containing carbamide peroxide (CP) bleaching agents and adhesive systems on bonded enamel interfaces that are part of the dynamic pH cycling and thermal cycling models. The buccal surfaces of 60 bovine incisors were restored with a composite resin and bonded with three- and two-step, etch-and-rinse, fluoride-containing adhesives, Optibond FL (FL) and Optibond Solo Plus (SP), respectively. Restored teeth were subjected to thermal cycling to age the interface. Both SP and FL adhesive-restored teeth were bleached (n = 10) with 10% CP (CP) and 10% CP + fluoride (CPF) or were left unbleached (control). Bleaching was performed for 14 days simultaneously with pH cycling, which comprised of 14 h of remineralization, 2 h of demineralization and 8 h of bleaching. The control groups (FL and SP) were stored in remineralizing solution during their bleaching periods and were also subjected to carious lesion formation. Parallelepiped-shaped samples were obtained from the bonded interface for microtensile bond strength (∝TBS) testing. The enamel ∝TBS of the FL and SP groups (control, not bleached) were higher (p < 0.05) than those of the bleached interfaces (FL > FL + CPF = FL + CP and SP > SP + CPF = SP + CP). The groups subjected to treatment with the fluoride-containing bleaching agents exhibited similar ∝TBS compared to regular bleaching agents. Bleaching agents, regardless of whether they contained fluoride, decreased enamel bond strength.

Evaluation of a strategic practice demonstration method applied to endodontic laboratory classes / Avaliação de um método estratégico de demonstração prática aplicado nas aulas de endodontia laboratorial

PURPOSE: To evaluate a strategic method of real time visual demonstration of the operatory procedures using an intraoral camera system and monitor videos, comparing them to those of conventional laboratory classes. METHODS: Fifty-two structured, multiple choice questionnaires were applied to undergraduate students of the 4th year (G1) and 3rd year (G2) submitted to the traditional and strategic teaching methods, respectively. These tests were also able to detect the main problems faced by the students during the training of this operatory phase. RESULTS: Students of both groups (G1- 30.8% and G2- 34.6%) considered the access cavity to be one of the most difficult phase of endodontic treatment. The results of the evaluation among the 3rd year students demonstrated that 23.1% graded the new method as excellent, 38.4% as very good and 38.5 % as good, whereas none of the students (0%) considered the method to be regular, bad or very bad. A minor accident occurrence (P<0.05) was reported by the 3rd year students (G1- 50% and G2- 34.6%). CONCLUSION: The new strategy was found to favor learning, reduce the incidence of errors and was appraised as efficient by the students.

OBJETIVO: Avaliar um método estratégico nas aulas práticas, utilizando micro câmeras e monitores de vídeo para transmitir demonstrações da técnica operatória, comparando-o com o método de ensino aprendizagem clássico. METODOLOGIA: Foram aplicados 52 questionários direcionados aos alunos do 4º ano (grupo 1) submetidos a esta nova prática e aos do 3º ano (grupo 2) submetidos a metodologia de ensino tradicional. Este questionário também possibilitou detectar os principais problemas enfrentados pelos discentes durante o aprendizado desta etapa operatória. RESULTADOS: A fase de cirurgia de acesso foi considerada de difícil execução por ambos os grupos (G1- 30,8 % e G2- 34,6%), sendo a manobra de localização dos orifícios de entrada dos canais a etapa mais complicada. Quanto à avaliação da metodologia empregada no 3º ano, 23,1% dos alunos a consideraram excelente, 38,4% ótima, e 38,5% boa, ao passo que nenhum dos estudantes (0%) consideraram o método como regular, ruim ou péssimo. Uma menor ocorrência de erros (P<0,05), foi relatada pelos alunos do 3º ano (G1- 50% e G2- 34.6%). CONCLUSÃO: A nova estratégia de ensino favoreceu a aprendizagem, diminuiu a incidência de erros e foi considerada eficaz pelos alunos.

Effect of fluoride-containing bleaching agents on bovine enamel microhardness

Aim: The purpose of this study was to evaluate the effect of 10% carbamide peroxide (10%CP) bleaching agents with different fluoride concentrations on enamel microhardness after induction of artificial caries lesions during pH-cycling model. Methods: Bovine dental enamel blocks with known surface microhardness were subjected to caries lesion induction and another surface microhardness was determined after a demineralization protocol. The enamel blocks were divided into four groups (n=17) and subjected to 12-day pH-cycling. The groups consisted of the following treatments: 1) artificial saliva (control group not subjected to bleaching treatment); 2) 10%CP; 3) 10%CP (with 0.11% fluoride); 4) 10%CP (with 0.5% fluoride). After treatments, the enamel was evaluated using surface microhardness, polarized light microscopy (PLM) and scanning electronic microscopy. The percentage of surface microhardness recovery was determined for each group and analyzed by the Kruskal Wallis and Dunn’s tests (a=0.05). The values of lesion depth by PLM were analyzed by ANOVA and Tukey’s test (a=0.05). Results: The enamel treated with bleaching gels containing or not fluoride presented lower mineral recovery and higher caries lesion depth than the control group. Conclusions: These data suggest that bleaching procedures on enamel with artificially induced caries lesions should be used with caution even in the presence of fluoride because there was no recovery in the microhardness.

Perfil antimicrobiano de cepas de Escherichia coli isolados de pessoas com suspeita de infecção do trato urinário / Antimicrobial profile of Escherichia coli strains isolated of peoples withsuspect of urinary tract infections

A infecção do trato urinário (ITU), situa-se entre as mais frequentes doenças bacterianas, sendo Escherichia coli um dos principais microrganismos causadores de ITU. Assim, o objetivo desse estudo foi verificar a incidência de cepas de E. coli na urina de indivíduos com suspeita de infecção urinária e avaliar o perfil de suscetibilidade a antimicrobiano dessas cepas. Foram analisadas 280 uroculturas, sendo 140 hospitalares e 140 de pessoas da comunidade, em três cidades do extremo oeste de Santa Catarina, Brasil. As urinas foram semeadas em ágar Macconkey, incubadas por 48 horas a 36 ± 1ºC. Colônias características foram identificadas por coloração de Gram e testes bioquímicos. O perfil desuscetibilidade a antimicrobianos foi realizada através da técnica de Kirby-Bauer conforme recomendações do CLSI 2005. Das 280 uroculturas analisadas, 79 (28,2%) foram positivas para Escherichia coli, destas 32 (40,5%) foram provenientes de amostras hospitalares e 47 (59,5%) de origem comunitária. O antimicrobiano de maior eficiência foi o imipenem e osantimicrobianos ampicilina, cefalotina e amicacina apresentaram maior índice de ineficácia para ambos os ambientes decoleta, demonstrando que o uso continuo e errôneo dos antimicrobianos favorecem o desenvolvimento de cepasresistentes, porque normalmente esses são drogas de primeira escolha e já não são mais eficientes nos tratamentos deITUs.

The urinary tract infection (UTI) is among the most frequent of all bacterial diseases and Escherichia coli is oneof the main microorganisms which causes the infection. Thus, the objective of this study was to verify the incidence of strains of E. coli in the individual's urine when urinary infection is suspected and to evaluate the susceptibility profile of the antimicrobials of these strains. A total of 280 urine cultures were analyzed. Half the cultures were taken from hospital patients and half were taken from people in communities located in three cities of the extreme west of Santa Catarina, Brazil. Theurine had been sown in Macconkey agar and incubated for 48 hours at 36± 1 ºC. Characteristic colonies had been identified by Gram coloration and biochemists tests. The susceptibility profile of the antimicrobials was carried through the technique in agreement with the Kirby-Bauer recommendations of CLSI 2005. Of the 280 analyzed urine cultures, 79 (28.2%) were positive for E. coli. Of these, 32 (40.5%) had come from hospital samples and 47 (59.5%) were of community-acquired origin.The antimicrobial with the most efficiency was imipenem. The ones with the worst efficiency were ampicillin, cephalothin and amikacin. This was true for cultures taken from both environments. It demonstrated that the continued and erroneous use of the antimicrobials contributed to the resistance development of strains, because these are normally drugs of first choice and already are less efficient in the treatment of ITUs.

Influence of the photoinitiator system and light photoactivation units on the degree of conversion of dental composites

The aim of this study was to observe the influence of two light polymerization units (LED or halogen light) on the degree of conversion (DC) of three dental composites with lighter shades and a different photoinitiator system. The top (T) and bottom (B) surfaces of 60 discs of composite resin (Filtek™ Supreme, Filtek™ Z250, Tetric™ Ceram Bleach) cured either by LED or by halogen lamp (HL) were studied using an FT-Raman spectrometer. The degree of conversion (DC) was evaluated by following the changes in the intensity of the methacrylate C=C stretching mode at 1640 cm-1. The calculated DC ranged from 54.2 percent (B) to 73.4 percent (T) and from 60.2 percent (B) to 76.6 percent (T) for the LED and HL, respectively. LED and halogen devices were able to produce an adequate DC for all the resins tested.

Influência da formação de película adquirida e aplicação tópica de flúor na microdureza do esmalte tratado com peróxido de hidrogênio a 35 por cento / Influence of acquired pellicle formation and topical fluoride application on microhardness of bleached enamel with 35 per cent hydrogen peroxide

O objetivo deste estudo foi avaliar a influência da formação da película adquirida (PEA) e da aplicação tópica de flúor (ATF) após o tratamento com peróxido de hidrogênio a 35% na microdureza Knoop do esmalte. Foram obtidas 120 amostras de esmalte (4x4x4 mm), a partir das superfícies vestibulares de 60 incisivos bovinos. As amostras foram preparadas para a leitura de microdureza de superfície (inicial) e aleatoriamente divididas em quatro grupos (n=30): (1) Esmalte sem formação de PEA e sem ATF pós-tratamento clareador (controle); (2) Esmalte sem formação de PEA e com ATF pós-tratamento clareador; (3) Esmalte com formação de PEA e sem ATF pós-tratamento clareador; (4) Esmalte com formação de PEA e com ATF pós-tratamento clareador. Os dentes foram submetidos a 12 dias de ciclagem de pH, concomitante com o clareamento (Pola Office, SDI, Bayswater, Victoria, Austrália), que foi realizado no 1º, 6º e 12º dia de ciclagem. Após a ciclagem de pH, foi realizada a leitura da microdureza superficial final e da microdureza longitudinal do esmalte tratado. Todos os grupos experimentais mostraram redução da microdureza superficial do esmalte após os tratamentos realizados. Os valores médios (iniciais e finais) foram semelhantes entre os grupos experimentais. Com relação à microdureza longitudinal, somente na primeira profundidade (10 μm) observou-se redução significativa da microdureza, com relação às demais profundidades analisadas. Esses valores médios, em 10 μm, não diferiram entre os grupos experimentais, assim como as outras profundidades analisadas também não diferiram entre os grupos. A microdureza do esmalte não foi afetada pela formação de PEA, tampouco pela ATF

The objective of this study was to evaluate the influence of acquired salivary pellicle formation (SPF) and the topical application of fluoride (TAF) post-bleaching with 35% hydrogen peroxide on the Knoop microhardness of enamel. Sixty bovine incisors were used. One hundred twenty enamel blocks (4x4x4 mm) were obtained from the buccal surfaces of these teeth. The enamel surfaces were prepared for microhardness measurements (baseline) and randomly divided into 4 groups (n=30): 1) enamel without SPF and TAF (control); 2) enamel without SPF and treated with ATF; 3) enamel with PEA and without ATF; and 4) enamel with PEA and treated with TAF. The enamel blocks were submitted to a 12-day pH-cycling, and the bleaching agent (Pola Office, SDI, Bayswater, Victoria, Australia) was applied at the 1st, 6th and 12th days of cycling. After the treatments, the surface microhardness and the internal microhardness were measured. All the groups showed a reduction in the enamel surface microhardness after the treatments. The mean values (baseline and final) were similar among the groups. The internal microhardness was lower at the first depth (10 μm). The mean values of microhardness at 10 μm were similar among the groups, and the other means did not differ among them. SPF and TAF did not affect enamel microhardness

Efeito da irradiação dos agentes clareadores no esmalte dental com lesão de cárie / Effect of bleaching agents irradiated on dental enamel with caries-like lesions

Analisar os efeitos do peróxido de hidrogênio (35%) irradiado ou não e do dentifrício fluoretado (DF) aplicados no esmalte dental com lesão de cárie. Foram analisados dois agentes clareadores (Whiteness HP Maxx e Easy White) e três modos de aplicação (sem irradiação, irradiação com aparelho de lâmpada halógena ou LED/laser de diodo). Os clareamentos foram realizados nos 1º, 6º e 12º dias de ciclagem de pH. Os resultados de microdureza mostraram que não houve diferença entre os grupos. A microscopia de luz polarizada mostrou desmineralização superficial e na subsuperfície do esmalte para todos os grupos. O DF não foi capaz de controlar a perda mineral provocada pelo clareamento, sugerindo cautela na indicação do clareamento em condições de atividade de cárie.

Characterization of water sorption, solubility and filler particles of light-cured composite resins

The goals of this study were to measure the water sorption (WS) and solubility (SO) of 3 composite resins containing different filler contents. Additionally, the size, shape, type and other characteristics of fillers were analyzed by scanning electron microscopy (SEM). Three composites, classified according to filler size, were selected: Filtek Supreme nanofill (3M/ESPE), Esthet-X minifill (Dentsply/Caulk) and Renamel microfill (Cosmedent Inc.). Ten disk-shaped specimens of each resin composite were made and stored in desiccators until constant mass was achieved. Specimens were then stored in water for 7 days, and the mass of each specimen was measured. The specimens were dried again and dried specimen mass determined. The WS and SO were calculated from these measurements. Data analyzed by one-way ANOVA and Tukey's post-hoc test (?=0.05). Composite filler particles were observed under SEM after removal of resin matrix by organic solvents. WS values were not significantly different among the resins; however, SO values were lower for Filtek Supreme. The materials presented differences in filler contents (e.g. particle size and shape). The composite resins had similar WS, while the SO was lower for the nanofill than for mini and microfill resins. The filler characteristics varied and were different among the materials.

Os objetivos deste estudo foram determinar a sorção de água (SA) e solubilidade (SO) de 3 resinas compostas que contêm diferentes conteúdos de partículas de carga. Adicionalmente, o tamanho, formato, tipo e outras características das partículas foram analisados em microscopia eletrônica de varredura (MEV). As resinas foram selecionadas de acordo com o tamanho das partículas: Filtek Supreme nanoparticulado (3M ESPE), Esthet-X microhíbrido (Dentsply Caulk) e Renamel microparticulado (Cosmedent Inc.). Dez espécimes com formato de disco de cada compósito foram confeccionados e armazenados em dessecador até obtenção de massa constante. Em seguida, os espécimes foram armazenados em água por 7 dias e a massa mensurada novamente. Os espécimes foram desidratados novamente e a massa final mensurada. A SA e a SO foram calculados a partir destas medidas. As partículas de carga dos compósitos foram observadas em MEV, após a remoção da matriz orgânica com solventes orgânicos. Os dados foram analisados por ANOVA e teste de Tukey (?=0.05). As médias de SA das resinas compostas foram semelhantes. A SO foi menor para o compósito Filtek Supreme. Os materiais contêm diferentes conteúdos de carga, em termos de formato e tamanho das partículas. As resinas compostas mostraram similar SA, enquanto o compósito nanoparticulado apresentou a menor SO. As características das partículas de carga foram diferentes entre os compósitos estudados.

Effect of 10 percent carbamide peroxide bleaching on sound and artificial enamel carious lesions

This study evaluated the effect of 10 percent carbamide peroxide (CP) bleaching on Knoop surface microhardness (KHN) and morphology of sound enamel and enamel with early artificial caries lesions (CL) after pH-cycling model (pHcm). Human dental enamel blocks were randomly divided into 6 groups (n=10): 1 - sound enamel bleached (S) with CP (Rembrandt/Den-Mat); 2 - S and submitted to pHcm; 3 - CL bleached with CP; 4 - CL stored in artificial saliva and submitted to pHcm; 5 - CL treated with placebo gel and submitted to pHcm; 6 - CL bleached with CP and submitted to pHcm. Enamel blocks with known initial KHN values were demineralized (groups 3 to 6) and submitted to 12 day pHcm (groups 2, 4, 5 and 6). After demineralization and treatments, KHN was determined and the specimens were examined using scanning electron microscopy (SEM). Data were analyzed statistically by ANOVA and Tukey's test at 5 percent significance level. The results showed that among CL groups (3 to 6) only the group 3 presented remineralization after treatments. S groups (1 and 2) showed higher KHN and presented less formation of porosities on enamel surface than CL groups after treatments. In conclusion, bleaching procedures on enamel with CL did not exacerbate the demineralization, but should be indicated with caution.

Este estudo analisou o efeito do peróxido de carbamida a 10 por cento (PC) na microdureza Knoop de superfície (KHN) e morfologia do esmalte hígido e com lesões iniciais de cárie artificial (EC), após modelo de ciclagem de pH (cpH). Blocos de esmalte dental humano foram divididos aleatoriamente em 6 grupos (n=10): 1- esmalte hígido clareado (EHC) com PC (Rembrandt/Den-Mat); 2- EHC e submetido a cpH; 3- EC clareado com PC; 4- EC armazenado em saliva artificial e submetido a cpH; 5- EC tratado com gel placebo e submetido a cpH; 6- EC clareado com PC e submetido a cpH. Blocos de esmalte com a KHN conhecida eram desmineralizados (grupos 3 a 6) e submetidos a cpH (grupos 2, 4, 5 e 6). KHN foi determinada após a desmineralização e os tratamentos. Os espécimes foram examinados através de Microscopia Eletrônica de Varredura (MEV). Os dados foram analisados através de ANOVA e teste de Tukey (p<0,05). Os resultados indicaram que entre os grupos com EC (3 a 6) somente o grupo 3 apresentou remineralização após os tratamentos. Os grupos EHC (1 e 2) mostraram maior KHN e menor formação porosidades quando comparados aos grupos EC após os tratamentos. Os procedimentos clareadores no esmalte com lesão de cárie não exacerbaram a desmineralização, entretanto precisam ser indicados com cautela.

Enamel susceptibility to red wine staining after 35 percent hydrogen peroxide bleaching

Concern has been expressed regarding the staining of enamel surface by different beverages after bleaching. This study investigated the influence of 35% hydrogen peroxide bleaching agents on enamel surface stained with wine after whitening treatments. Flat and polished bovine enamel surfaces were submitted to two commercially available 35% hydrogen peroxide bleaching agents or kept in 100% humidity, as a control group (n = 10). Specimens of all groups were immersed in red wine for 48 h at 37°C, immediately, 24 h or 1 week after treatments. All specimens were ground into powder and prepared for the spectrophotometric analysis. Data were subjected to two-way analysis of variance and Fisher’s PLSD test at 5% significance level. The amount of wine pigments uptake by enamel submitted to bleaching treatments was statistically higher than that of control group, independently of the evaluation time. Results suggested that wine staining susceptibility was increased by bleaching treatments.

Effect of storage and disinfection methods of extracted bovine teeth on bond strength to dentin

The aim of this study was to evaluate the effect of storage and disinfection methods (SDM) on bond strength (BS) to bovine dentin, using two adhesive systems: Adper Single Bond and Clearfil Protect Bond. Method: Extracted bovine teeth were assigned to the following SDM: 100% Humidity (HU); Gamma Radiation (GR); Autoclave (AU); 0.10g/mL Thymol (TH); 10% Formalin (FO); Frozen (FR); 0.2% Sodium Azide (SA) and 0.5% Chloramine T (CT) (n=10). The GR and AU groups were submitted to sterilization methods and stored at 100% humidity for 24 hours at 37Cº, before testing. TH,FO, FR, SA and CT groups were stored for three months at 5Cº, except for FR (-4Cº). The adhesive systems were applied according to manufacturerÆs instructions. For BS testing, the micro-shear test was performed, using Tygon mold (0.75mm diameter and 1mm high), which was filled with Clearfil AP-X (Kuraray) composite resin. Data were analyzed by two-way ANOVA and Tukey Test (p<0.05). BS of adhesive systems was similar for all SDM, except for 10%formalin. HU, GR, AU, TH and SA did not change the BS for the adhesives tested. For most of SDM, BS of adhesive systems was similar. Some 3 month-SDM groups (FR, FO and CT) reduced the BS.