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Braz. j. oral sci ; 20: e213859, jan.-dez. 2021. ilus
Article in English | LILACS, BBO | ID: biblio-1253923


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

Animals , Cattle , Tooth Bleaching , Dental Enamel , Shear Strength
Rev. Fac. Odontol. Porto Alegre ; 61(2): 50-63, jul-dez. 2020.
Article in English | LILACS, BBO | ID: biblio-1281698


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)

Humans , Male , Female , Adult , Middle Aged , Young Adult , Composite Resins , Dental Restoration, Permanent/methods , Bicuspid , Double-Blind Method , Follow-Up Studies , Statistics, Nonparametric , Molar
J. appl. oral sci ; 28: e20190720, 2020. tab, graf
Article in English | LILACS, BBO | ID: biblio-1134776


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.

Humans , Male , Female , Adolescent , Adult , Phototherapy/methods , Tooth Bleaching/methods , Tooth Bleaching Agents/administration & dosage , Carbamide Peroxide/administration & dosage , Hydrogen Peroxide/administration & dosage , Light , Reference Values , Spectrophotometry , Surface Properties/drug effects , Surface Properties/radiation effects , Risk Factors , Analysis of Variance , Treatment Outcome , Colorimetry , Combined Modality Therapy , Statistics, Nonparametric , Dental Enamel/drug effects , Dental Enamel/radiation effects , Dentin Sensitivity/chemically induced
Braz. j. oral sci ; 18: e191406, jan.-dez. 2019. tab
Article in English | LILACS, BBO | ID: biblio-1094951


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

Animals , Cattle , Orthodontics , Materials Testing , Dental Bonding , Shear Strength
J. appl. oral sci ; 26: e20170589, 2018. tab, graf
Article in English | LILACS, BBO | ID: biblio-954496


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.

Animals , Cattle , Calcium/chemistry , Tooth Demineralization/chemically induced , Dental Enamel/drug effects , Tooth Bleaching Agents/chemistry , Fluorides/chemistry , Hydrogen Peroxide/chemistry , Phosphates/chemistry , Reference Values , Spectrometry, X-Ray Emission , Spectrum Analysis, Raman , Surface Properties/drug effects , Time Factors , Tooth Bleaching/adverse effects , Tooth Bleaching/methods , Materials Testing , Carbonates/chemistry , Reproducibility of Results , Dental Enamel/chemistry , Tooth Bleaching Agents/adverse effects , Hardness Tests , Microscopy, Polarization
Braz. oral res ; 26(6): 536-542, Nov.-Dec. 2012. ilus, tab
Article in English | LILACS | ID: lil-656697


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.

Animals , Cattle , Dental Bonding/methods , Dental Enamel/drug effects , Fluorides/chemistry , Peroxides/chemistry , Resin Cements/chemistry , Tooth Bleaching Agents/chemistry , Urea/analogs & derivatives , Dental Restoration Failure , Dentin/drug effects , Tensile Strength , Time Factors , Tooth Demineralization , Urea/chemistry
Rev. odonto ciênc ; 27(2): 127-131, 2012. ilus, tab
Article in English | LILACS, BBO | ID: lil-649736


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.

Education, Dental , Endodontics , Learning
Braz. j. oral sci ; 10(1): 22-26, jan.-mar. 2011. ilus, tab
Article in English | LILACS, BBO | ID: lil-589646


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.

Dental Enamel , Fluorides , Tooth Bleaching
Rev. bras. anal. clin ; 43(2): 145-147, 2011. tab
Article in Portuguese | LILACS | ID: lil-605691


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.

Humans , Male , Female , Young Adult , Disk Diffusion Antimicrobial Tests , Escherichia coli , Escherichia coli Infections , Imipenem , Urinary Tract Infections , Amikacin , Ampicillin Resistance , Cefoxitin , Ceftriaxone , Cephalothin , Ciprofloxacin , Gentamicins , Norfloxacin
Braz. oral res ; 24(4): 475-481, Oct.-Dec. 2010. ilus, tab
Article in English | LILACS | ID: lil-569229


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.

Curing Lights, Dental , Composite Resins/radiation effects , Photoinitiators, Dental , Polymerization/radiation effects , Composite Resins/chemistry , Materials Testing , Spectrum Analysis, Raman , Statistics, Nonparametric , Surface Properties , Time Factors
Braz. dent. sci ; 13(1/2): 10-15, 2010. tab, graf
Article in Portuguese | LILACS, BBO | ID: lil-642685


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

Animals , Cattle , Dental Enamel , Dental Pellicle , Fluorides, Topical , Hardness , Hydrogen Peroxide , Tooth Bleaching
Rev. bras. odontol ; 66(2): 270-275, jul.-dez. 2009. tab, ilus
Article in Portuguese | LILACS, BBO | ID: lil-562677


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.

Animals , Cattle , Dental Caries/complications , Tooth Bleaching/adverse effects , Dental Enamel , Lasers , Hydrogen Peroxide/therapeutic use
Braz. dent. j ; 20(4): 314-318, 2009. tab, ilus
Article in English | LILACS | ID: lil-536321


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.

Composite Resins/chemistry , Dental Restoration, Permanent , Light-Curing of Dental Adhesives , Nanoparticles/chemistry , Polymethacrylic Acids/chemistry , Water/analysis , Absorption , Microscopy, Electron, Scanning , Solubility
Braz. dent. j ; 20(1): 48-53, 2009. ilus, tab
Article in English | LILACS, SES-SP | ID: lil-513913


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.

Humans , Dental Caries/pathology , Dental Enamel/drug effects , Oxidants/adverse effects , Peroxides/adverse effects , Tooth Bleaching/adverse effects , Tooth Demineralization/chemically induced , Urea/analogs & derivatives , Dental Enamel/pathology , Dental Enamel/ultrastructure , Drug Combinations , Hardness/drug effects , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Porosity , Saliva, Artificial , Tooth Remineralization , Urea/adverse effects
J. appl. oral sci ; 16(3): 201-204, May-June 2008. ilus, tab
Article in English | LILACS, BBO | ID: lil-483154


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.

Animals , Cattle , Dental Enamel , Hydrogen Peroxide , Tooth Bleaching
Braz. j. oral sci ; 6(22): 1402-1406, July-Sept. 2007. tab
Article in English | LILACS, BBO | ID: lil-518167


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.

Animals , Cattle , Dentin , Dentin-Bonding Agents , Disinfection/methods , Sterilization
J. appl. oral sci ; 14(2): 82-87, Apr. 2006. ilus, tab
Article in English | LILACS, BBO | ID: biblio-873200


OBJETIVO: O propósito deste estudo foi avaliar os efeitos de agents clareadores à base de peróxido de carbamida (CPG) contendo fluoreto (CF) e cálcio (CCa) na resistência à tração do esmalte (UTS). MÉTODO: Um bloco de resina composta foi confeccionada na superfície oclusal de vinte e dois terceiros molars hígidos para facilitar a preparação dos espécimes para o teste de micro-tração. Os dentes restaurados foram seccionados com disco diamantado no sentido vestíbulo-lingual em fatias de aproximadamente 0,7 mm de espessura. Com uma ponta diamantada, foi realizada uma constrição na região de esmalte da vertente oclusal interna. Os espécimes apresentaram aproximadamente 0,5 mm² de área na secção transversal da região de constrição e foram divididos em 12 grupos (n=11). Os grupos controles não foram submetidos ao regime clareador e os experimentais foram tratados com gel de CPG 10 por cento ou com formulações de CPG 10 por cento contendo CF (0,2 por cento e 0,5 por cento) ou CCa (0,05 por cento e 0,2 por cento). Os grupos clareadores receberam a aplicação dos CPGs por 6 horas/dia a 37ºC, durante 14 dias consecutivos e foram armazenados em saliva artificial (AS) ou em umidade relativa 100 por cento (RH), entre as aplicações do gel clareador. Após o clareamento, os espécimes foram testados através do método de micro-tração (0,5 mm/min). Os dados foram analisados pela ANOVA (2 fatores) e teste Tukey (5 por cento). RESULTADOS: Nenhuma diferença foi observada entre os grupos armazenados em AS ou RH. Os espécimes tratados com CPG com CF ou Cca apresentaram similar UTS aos grupos controles não clareados. CONCLUSÃO: Ambos CPGs 10 por cento CF or CCa não alteraram a UTS após o tratamento clareador

Calcium , Dental Enamel , Hydrogen Peroxide , Sodium Fluoride , Tensile Strength , Tooth Bleaching , Tooth Demineralization
J. appl. oral sci ; 14(2): 82-87, Apr. 2006. ilus, tab
Article in English | LILACS, BBO | ID: lil-448142


OBJECTIVE: The aim of this study was to evaluate the effects of carbamide peroxide-based bleaching agents (CPG) containing fluoride (CF) or calcium (CCa) on the ultimate tensile strength of enamel (UTS). METHOD: A "cube-like" resin composite structure was built-up on the occlusal surface of twenty-two sound third molars to facilitate specimen preparation for the micro-tensile test. The restored teeth were serially sectioned in buccal-lingual direction in slices with approximate 0.7 mm thickness. Each slice was trimmed with a fine diamond bur to reduce the buccal, internal slope enamel of the cusps to a dumb-bell shape with a cross-sectional area at the "neck" of less than 0.5 mm². The samples were randomly divided into 12 groups (n=11). The control groups were not submitted to the bleaching regimen. Specimens were treated with 10 percent CPG gel or with 10 percent CPG formulations containing CF (0.2 percent and 0.5 percent) or CCa (0.05 percent and 0.2 percent). Bleached groups received the application of the 10 percent CPGs for 6 hours/day at 37° C, during 14 consecutive days and were stored in artificial saliva (AS) or 100 percent relative humidity (RH) among each application. After bleaching, specimens were tested with the microtensile method at 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey test (5 percent). RESULTS: No significant difference was observed between groups stored in AS or RH. Specimens treated with CF or CCa presented similar UTS as unbleached control groups. CONCLUSION: Either 10 percent CPG formulations containing CF or CCa can preserve the UTS after bleaching regimen.

OBJETIVO: O propósito deste estudo foi avaliar os efeitos de agents clareadores à base de peróxido de carbamida (CPG) contendo fluoreto (CF) e cálcio (CCa) na resistência à tração do esmalte (UTS). MÉTODO: Um bloco de resina composta foi confeccionada na superfície oclusal de vinte e dois terceiros molars hígidos para facilitar a preparação dos espécimes para o teste de micro-tração. Os dentes restaurados foram seccionados com disco diamantado no sentido vestíbulo-lingual em fatias de aproximadamente 0,7 mm de espessura. Com uma ponta diamantada, foi realizada uma constrição na região de esmalte da vertente oclusal interna. Os espécimes apresentaram aproximadamente 0,5 mm² de área na secção transversal da região de constrição e foram divididos em 12 grupos (n=11). Os grupos controles não foram submetidos ao regime clareador e os experimentais foram tratados com gel de CPG 10 por cento ou com formulações de CPG 10 por cento contendo CF (0,2 por cento e 0,5 por cento) ou CCa (0,05 por cento e 0,2 por cento). Os grupos clareadores receberam a aplicação dos CPGs por 6 horas/dia a 37°C, durante 14 dias consecutivos e foram armazenados em saliva artificial (AS) ou em umidade relativa 100 por cento (RH), entre as aplicações do gel clareador. Após o clareamento, os espécimes foram testados através do método de micro-tração (0,5 mm/min). Os dados foram analisados pela ANOVA (2 fatores) e teste Tukey (5 por cento). RESULTADOS: Nenhuma diferença foi observada entre os grupos armazenados em AS ou RH. Os espécimes tratados com CPG com CF ou Cca apresentaram similar UTS aos grupos controles não clareados. CONCLUSÃO: Ambos CPGs 10 por cento CF or CCa não alteraram a UTS após o tratamento clareador.

Tooth Bleaching , Calcium , Dental Enamel , Sodium Fluoride , Hydrogen Peroxide , Tensile Strength , Tooth Demineralization
Braz. oral res ; 19(1): 23-29, Jan.-Mar. 2005. ilus
Article in English | LILACS | ID: lil-403730


Este estudo avaliou a resistência de união de dois sistemas adesivos ao esmalte e à dentina após a aplicação de agente clareador sobre a união compósito-dente. Dezesseis terceiros molares humanos foram usados nos procedimentos restauradores. Single Bond (SB) e Clearfil SE Bond (CB) foram aplicados no esmalte e na dentina de acordo com as instruções dos fabricantes. Um bloco de compósito foi construído nas superfícies tratadas com os adesivos. Os dentes restaurados foram seccionados em fatias com espessura de 0,7 mm, que receberam constrição na interface de união num formato de ampulheta, com área de secção transversal de ± 0,5 mm2. Os espécimes foram distribuídos em 8 grupos (n = 10) de acordo com os fatores em estudo: substrato dental (esmalte e dentina); sistema adesivo (SB e CB) e tratamento (peróxido de carbamida a 10% e controle). O agente clareador (Opalescence) foi aplicado na interface de união por 6 horas durante 14 dias e, após o tratamento diário, os espécimes foram armazenados em saliva artificial. Os espécimes não clareados foram mantidos em saliva artificial por 14 dias. Os espécimes foram testados e os dados foram analisados pela ANOVA (três fatores) e pelo teste Tukey (p < 0,05). A resistência à tração do esmalte tratado com o adesivo CB foi reduzida após aplicação do peróxido de carbamida, entretanto, a resistência de união em dentina para ambos os adesivos não foi modificada. Os resultados sugerem que o clareamento afeta a resistência de união do CB ao esmalte, mas nenhuma influência foi observada em dentina.

Humans , Bisphenol A-Glycidyl Methacrylate , Dental Bonding , Dental Enamel/drug effects , Dentin/drug effects , Peroxides/pharmacology , Resin Cements , Urea/analogs & derivatives , Analysis of Variance , Drug Combinations , Dental Enamel/ultrastructure , Dentin/ultrastructure , Microscopy, Electron, Scanning , Saliva, Artificial , Tensile Strength , Tooth Bleaching/methods , Urea/pharmacology
Braz. oral res ; 18(4): 306-311, Oct.-Dec. 2004. ilus, tab
Article in English | LILACS | ID: lil-398749


O objetivo deste estudo foi avaliar a rugosidade, microdureza e morfologia superficial do esmalte dental humano tratado com seis agentes clareadores (antes e depois do tratamento). Amostras de esmalte dental humano foram obtidas de terceiros molares e aleatoriamente distribuídas em sete grupos (n = 11): controle, Whiteness Perfect - peróxido de carbamida a 10% (PC 10%), Colgate Platinum - PC 10%, Day White 2Z - peróxido de hidrogênio a 7,5% (PH 7,5%), Whiteness Super - PC 37%, Opalescence Quick - PC 35% e Whiteness HP - PH 35%. Os agentes clareadores foram aplicados de acordo com as instruções dos fabricantes. O grupo controle permaneceu sem tratamento e armazenado em saliva artificial. O teste de microdureza foi realizado com o indentador Knoop, e a rugosidade superficial foi verificada através do rugosímetro. Observações morfológicas foram realizadas através de microscopia eletrônica de varredura (MEV). Os resultados foram estatisticamente analisados com ANOVA (dois fatores) e teste Tukey (5%) e revelaram uma redução significante nos valores de microdureza e um aumento significante da rugosidade de superfície após o clareamento. Alterações na morfologia do esmalte após o clareamento foram observadas através de MEV. Concluiu-se que os agentes clareadores podem alterar a microdureza, rugosidade e morfologia superficial do esmalte dental.

Humans , Dental Enamel/drug effects , Hardness/drug effects , In Vitro Techniques , Oxidants/pharmacology , Peroxides/pharmacology , Tooth Bleaching , Urea/analogs & derivatives , Case-Control Studies , Drug Combinations , Dental Enamel/ultrastructure , Microscopy, Electron, Scanning , Molar/drug effects , Molar/ultrastructure , Oxidants/adverse effects , Peroxides/adverse effects , Random Allocation