A higiene bucal de bebês edêntulos e sua influência na microbiota bucal: os profissionais de saúde devem preconizá-la? ­ revisão crítica / Oral hygiene in edentulous infants and its influence on oral microbiota: should the health professionals recommend it? ­ a critical review

Introdução: A indicação de higiene bucal em bebês edêntulos entre os profissionais de saúde ainda é controversa, sendo necessária a busca científica sobre esta indicação e a padronização da informação. Objetivo: Investigar criticamente as evidências relacionadas a indicação da higiene bucal para bebês edêntulos. Métodos: A busca de artigos foi realizada nas bases de dados PubMed, LILACS e Google Scholar, de modo a avaliar a seguinte pergunta: "A higienização da cavidade bucal de bebês edêntulos pode influenciar a microbiota bucal?". Uma busca em 8 livros de Odontopediatria também foi realizada. Resultados: Foram encontrados 317 artigos (167-PubMed, 146-Google Scholar e 4-LILACS). Não foram encontrados estudos primários que avaliaram o efeito da higiene bucal em bebês edêntulos na microbiota, impossibilitando a condução de revisão sistemática. Assim, para a revisão foram incluídos 6 estudos que investigaram micro-organismos na cavidade bucal de bebês edêntulos e o papel das imunoglobulinas salivares. Dentre os livros avaliados, somente 4 indicaram a higiene bucal em bebês edêntulos. Conclusão: Diante dos dados analisados, não existem estudos primários que avaliaram o efeito da higienização na microbiota bucal de bebês edêntulos. Torna-se relevante a condução de estudos clínicos para obtenção de evidências científicas sobre a indicação ou não da higienização da cavidade bucal de bebês edêntulos.

Introduction: The indication of oral hygiene in edentulous babies is still controversial among health professionals, being necessary the search of this recommendation and the standardization of information. Objective: To inves-tigate critically the evidence related to the indication of oral hygiene for edentulous babies. Methods: The search for articles was performed in the PubMed, LILACS and Google Scholar databases, in order to assess the following question: "Can oral cavity hygiene of edentulous babies influence oral microbiota?" A search in 8 books of Pediatric Dentistry was also performed. Results: 317 articles were found (167-PubMed, 146-Google Scholar and 4-LILACS). There were no primary studies that evalu-ated the effect of oral hygiene of edentulous infants on microbiota, which impair the conduction of a systematic review. Thus, it was included for this review six studies that investigated microorganisms in the oral cavity of edentulous infants and the role of salivary immunoglo- bulins. Among the textbooks evaluated, only 4 indicated the oral hygiene in edentulous infants. Conclusion:According to the data, there are no primary studies that assessed the effect of oral hygiene in the oral microbiota of edentulous babies. It is relevant to conduct clinical studies in order to obtain scientific evidence about the indication or no of the oral hygiene in edentulous babies

Weight-loss and surface roughness of enamel after microabrasion procedure with different agents / Perda de peso e rugosidade da superfície do esmalte após procedimento de microabrasão com diferentes agentes

Introduction: Enamel microabrasion is achieved by abrasion of the enamel surface and it is a quick, practical and efficient procedure. Objective It was assessed the weight loss and surface aspect of enamel after microabrasion procedures with commercial and mixtures made in-office. Material and method Eighty bovine incisors were divided into four groups (n=10): OpalustreTM (6.6% HCl + silicon carbide); Whiteness RMTM (6% HCl + silicon carbide); 37% H3PO4 + pumice and 10% HCl + pumice. Treatment was performed by 15 applications of 10s duration. The enamel weight loss was determined by the difference in weight before and after the microabrasion. The surfaces were analyzed by a surface roughness equipment and scanning electron microscopy. Data were submitted to paired-T test, one-way ANOVA and Tukey tests (α=0.05). Result It was observed significantly weight loss for all groups. The difference in weight loss ranged from 0.037±0.012 for group 37% H3PO4 and from 0.054±0.009 for group 6,6% HCl. There was a significant increase in surface roughness for all groups and 10% HCl group showed the lower results (0.65±0.09). It was observed different patterns of enamel morphology by SEM images. Conclusion The in-office mixtures resulted in the lowest enamel structure loss (37% H3PO4) and the lowest surface roughness (10% HCl).

Introdução: A microabrasão do esmalte é realizada através da abrasão da superfície do mesmo, apresentando-se como um procedimento rápido, prático e eficiente. Objetivo Avaliar a perda de peso e o aspecto superficial do esmalte após procedimentos de microabrasão com agentes comerciais e não comerciais. Material e método Oitenta incisivos bovinos foram divididos em quatro grupos (n = 10): OpalustreTM (6,6% HCl + carboneto de silício); Whiteness RMTM (6% HCl + carboneto de silício); 37% H3PO4 + pedra-pomes e 10% HCl + pedra-pomes. O tratamento foi realizado em 15 aplicações de 10s de duração. A perda de peso do esmalte foi determinada pela diferença de peso antes e depois da microabrasão. As superfícies foram analisadas por equipamento de rugosidade superficial e microscopia eletrônica de varredura. Os dados foram submetidos ao teste T-pareado, ANOVA one-way e teste de Tukey (α = 0,05). Resultado Foi observada perda de peso significativa para todos os grupos, a diferença na perda de peso variou de -0,037±0,012 para o grupo 37% H3PO4 a -0.054±0.009 para o grupo 6.6% HCl. Houve um aumento significativo na rugosidade da superfície para todos os grupos e o grupo 10%HCl apresentou os resultados mais baixos (0,65±0,09). Foram observados diferentes padrões de morfologia do esmalte por meio de imagens MEV. Conclusão Os agentes não comerciais resultaram na menor perda de estrutura do esmalte (37% H3PO4) e na rugosidade superficial (10% HCl).

Synthesis of a chitosan nanoparticle suspension and its protective effects against enamel demineralization after an in vitro cariogenic challenge

Abstract Objective Our study aims to synthesize, characterize, and determine the effects of a ChNPs suspension on human enamel after cariogenic challenge via pH-cycling. Methodology ChNPs were synthesized by ion gelation and characterized by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering. Forty enamel blocks were divided into four groups (n=10/group): (i) ChNPs suspension; (ii) chitosan solution; (iii) 0.05% sodium fluoride (NaF) solution; and (iv) distilled water. Specimens were exposed to cariogenic challenge by cycling in demineralization solution (3 h) and then remineralized (21h) for 7 days. Before each demineralization cycle, the corresponding solutions were passively applied for 90 s. After 7 days, specimens were examined for surface roughness (Ra) and Knoop hardness (KHN) before and after the cariogenic challenge; % KHN change (variation between initial and final hardness), and surface topography by an optical profilometer. The data were analyzed by repeated-measures ANOVA, One-way ANOVA, and Tukey tests (α=0.05). Results TEM images showed small spherical particles with diameter and zeta potential values of 79.3 nm and +47.9 mV, respectively. After the challenge, all groups showed an increase in Ra and a decrease in KHN values. Optical profilometry indicated that ChNPs- and NaF-treated specimens showed uneven roughness interspersed with smooth areas and the lowest %KHN values. Conclusion The ChNPs suspension was successfully synthesized and minimized human enamel demineralization after a cariogenic challenge, showing an interesting potential for use as an oral formulation for caries prevention.

Effect of hydrochloric acid commercial presentation for microabrasion technique on loss of enamel structure and surface / Efeito da apresentação comercial de ácido clorídrico para técnica de microabrasão na perda de estrutura e superfície do esmalte

Introdução: A técnica de microabrasão pode ser realizada através de pasta pronta para uso, disponível comercialmente, ou o profissional pode manipulá-la no consultório. Objetivo: Verificar o efeito da apresentação comercial do ácido clorídrico a 10% na manipulação de pasta para microabrasão sobre a superfície do esmalte. Metodologia: Foram selecionados incisivos bovinos e divididos em dois grupos, de acordo com a apresentação comercial do ácido clorídrico (líquido ou em gel). O tratamento foi realizado através de dez aplicações com 10s de duração cada, intercaladas por lavagem de 10s. Vinte incisivos (n=10) foram utilizados para se determinar a perda de estrutura do esmalte. Cada amostra foi pesada, em balança analítica, antes e após submissão à microabrasão. Outras 20 amostras (n=10) foram utilizadas para determinação da rugosidade superficial média (Ra) utilizando-se um rugosímetro. Três amostras de cada grupo do experimento anterior foram selecionadas, aleatoriamente, e outras três amostras adicionais foram preparadas como controle (baseline) para análise em MEV. Resultados: Verificou-se diferença estatística significativa entre a massa final e a inicial e rugosidade superficial das amostras, independente da apresentação comercial do ácido. Nas imagens de MEV observou-se presença de superfície regular para o grupo controle (baseline). Nas demais imagens verificou-se superfície com considerável irregularidade e dissolução discreta do esmalte. Conclusões: O tratamento realizado causou perda significativa de estrutura e aumentou a rugosidade superficial dos espécimes, independente da apresentação comercial do ácido e sem apresentar diferença entre os grupos ao final. A apresentação comercial do ácido não parece ser um fator a interferir no tratamento. (AU)

Introduction: The microabrasion technique can be performed using a commercially available paste, or the dentist can prepare it in his office. Objective: To verify the effect of hydrochloric acid commercial presentation in the handling of microabrasion paste on the enamel surface. Methodology: Bovine incisors were divided into two groups, according to the commercial presentation of 10% hydrochloric acid (liquid or gel). The treatment was carried out through ten applications of 10 s duration each, intercalated with a 10s wash. Twenty teeth (n=10) were used to determine the loss of enamel structure. Each sample was weighed on an analytical balance before and after submission to microabrasion. Another 20 teeth (n=10) were used to determine the average surface roughness (Ra) using a rugosimeter. Three samples from each group of the previous experiment were selected, randomly, and another three additional samples were repared as a control (baseline) for SEM analysis. Results: There was a statistically significant difference between the final and initial mass and the surface roughness of the samples, regardless of the acid commercial presentation. In the SEM images, a regular surface was observed for the control group (baseline). In the other images, there was a surface with considerable irregularity and a slight dissolution of the enamel. Conclusions: The treatment carried out. (AU)

In Vitro Effect of Acidic Challenges on the Physical Properties of Dental Prosthesis Artificial Teeth

Abstract Objective: To evaluate the effect of immersion and acid challenge with cola drink on color change (ΔE), Vickers hardness (VHN) and surface roughness (Ra) of artificial acrylic resin teeth. Material and Methods: The artificial teeth were divided into 6 groups (n= 8): TC (Trilux/Control), BC (Biotone/Control), TAC (Trilux/Acid challenge), BAC (Biotone/Acid challenge), TI (Trilux/Immersion) and BI (Biotone/Immersion). The teeth were embedded in acrylic resin and the labial side was serially polished to provide appropriate flat surface. The samples of TC, BC, TI, BI groups were immersed in artificial saliva and cola drink (coke) for 7 days, respectively. The acid challenge was performed with immersion of samples in coke for 5 min, and subsequently immersion in artificial saliva for 2h. This cycle was repeated at 4 times/day, during 7 days. The tests of VHN, ΔE and Ra were analyzed before and after the challenge and immersion groups. Data was analyzed by ANOVA, Tukey and T test (α = 0.05). Results: There was no difference in Ra values between groups after treatments. However, there was a decrease in VHN for all groups. BI (19.2 ± 0.3) presented significantly lower hardness than BAC (19.5 ± 0.9) and BC (20.2 ± 0.5). Groups BI (2.18 ± 0.41) and TI (1.50 ± 0.43) had statistically higher ΔE compared to the other groups. Conclusion: The hardness of resin teeth decreased after acid challenges, but the roughness surface was not affected. The color was more affected by the times of exposure in cola beverage and remineralization in artificial saliva, which were associated to the material degradation (AU).

Os medicamentos infantis podem causar erosão na superfície de dentes decíduos? Revisão sistemática da literatura / Can child medications cause erosion on the surface of deciduous teeth? A systematic review of literature

Introdução: A erosão dentária é caracterizada por uma perda progressiva e irreversível dos tecidos dentários mineralizados que ocorre sem envolvimento bacteriano. Acredita-se que o uso frequente de medicamentos líquidos orais, em crianças, possa desenvolver erosão dentária visto que esses medicamentos apresentam, em sua maioria, pH ácido, que pode atuar como fator predisponente ao desenvolvimento da erosão dentária. Objetivo: O presente estudo avaliou os efeitos do uso de medicamentos líquidos orais na estrutura de dentes decíduos por meio de revisão sistemática da literatura. Material e Métodos: Foi realizada pesquisa de artigos científicos, em março de 2018, nas bases de dados PubMed e Web of Science utilizando descritores específicos para a pesquisa, de modo a avaliar, descritivamente, a seguinte pergunta "Os medicamentos infantis de uso contínuo podem causar erosão na superfície de dentes decíduos?" Foram encontrados 278 artigos na base de dados Pubmed e 41 na base Web of Science, dos quais 18 artigos eram coincidentes, assim 301 títulos e resumos foram lidos e analisados. Destes, 293 foram excluídos de modo que 8 artigos foram selecionados para análise crítica. Resultados: Os medicamentos líquidos de uso contínuo, geralmente utilizados para o tratamento de condições crônicas em crianças, promovem efeito erosivo sobre a estrutura dentária, principalmente quando relacionado ao pH e acidez titulável dos medicamentos, por avaliação de estudos conduzidos "in vitro". Conclusão: Torna-se necessária a realização de estudos clínicos para avaliação mais adequada do efeito erosivo de medicamentos infantis na superfície de dentes decíduos.

Introduction: Dental erosion is characterized by a progressive and irreversible loss of mineralized dental tissues that occurs without bacterial involvement. It is believed that the frequent use of oral liquid medicines in children can develop dental erosion since the majority of these medications has acidic pH, which can act as a predisposing factor for dental erosion development. Objective: The present study evaluated the effects of the use of liquid oral medications on the structure of deciduous teeth by a systematic review of literature. Material and Methods: We conducted a survey of scientific articles in PubMed and Web of Science databases on March 2018, using specific descriptors for the research, in order to evaluate descriptively the following question: "Children's medicines for continuous use may cause erosion on the surface of deciduous teeth?". We found 278 articles in the PubMed database and 41 in the Web of Science database, of which 18 articles were matched, so 301 titles and abstracts were read and analyzed. Of these, 293 were excluded. Thus, 8 articles were selected for the critical analysis. Results: Liquid medications of continuous use, generally used for the treatment of chronic conditions in children, promoted erosive effect on dental structure, especially when related to pH and titratable acidity of the drugs in in vitro studies. Conclusion:It is necessary to carry out clinical studies for a more adequate evaluation of the erosive effect of children's medicines on the surface of deciduous teeth.

Qual material possui maior longevidade em molares decíduos: resina composta ou cimento de ionômero de vidro? - revisão sistemática da literatura / Which material has the highest longevity in primary molars: composite resin or glass ionomer cement? - a systematic review of the literature

Introdução: Diversos materiais restauradores são indicados para a restauração de dentes decíduos posteriores, como amálgama, resina composta, cimento de ionômero de vidro convencional, cimento de ionômero de vidro modificado por resina e resinas compostas modificadas com poliácidos (compômeros). Entretanto, uma dúvida ainda persiste quanto ao desempenho clínico do cimento de ionômero de vidro, em decorrência de suas propriedades, para ser utilizado como material restaurador definitivo em molares decíduos. Objetivo: Realizar uma revisão sistemática da literatura acerca da taxa de sobrevivência de restaurações realizadas em molares decíduos utilizando resina composta e cimento de ionômero de vidro, buscando com base em evidências científicas, responder a PICO question: "Qual material possui maior longevidade em molares decíduos: resina composta ou cimento de ionômero de vidro?". Material e métodos: Para este fim foram realizadas buscas em duas bases de dados, PubMed e Web of Science, utilizando uma estratégia de busca previamente determinada, para selecionar artigos de acordo com critérios de inclusão e exclusão criados para esse trabalho por dois examinadores calibrados. Resultados: A seleção dos artigos foi realizada de acordo com o fluxograma do PRISMA e foi criada uma tabela para avaliação qualitativa dos artigos selecionados. Foram encontrados 398 artigos na base de dados PubMed e 375 na Web of Science, sendo 153 coincidentes em ambas. Quarenta e seis artigos foram selecionados para leitura completa, dentre eles 42 foram excluídos, e quatro artigos foram incluídos para esta revisão. Conclusão: Os artigos desta revisão demonstraram que a resina composta possuiu maior longevidade em molares decíduos comparada aos cimentos de ionômero de vidro. Porém futuros estudos clínicos necessitam ser conduzidos para comprovar qual o material mais indicado para restaurá-los, já que os cimentos de ionômero modificados por resina mostraram taxas de sobrevivência clínica satisfatórias.

Introduction: Several restorative materials are indicated for restoration of posterior deciduous teeth, such as amalgam, composite resin, conventional glass ionomer cement, resin modified glass ionomer cement and composite resins modified with polyacids (compomers). However, a doubt still persists related to the clinical performance of the glass ionomer cements to be used to restore deciduous molars, due to its properties. Objective: To perform a systematic review of the literature about the survival rate of composite resin and glass ionomer cement restorations performed in deciduous molars aiming scientific evidence to answer the PICO question: "Which material has greater longevity in deciduous molars: resin composite or glass ionomer cement?" Material and methods: The research was performed on two databases, PubMed and Web of Science, using a predetermined search strategy to select articles according to the inclusion and exclusion criteria, evaluated by two calibrated examiners. Results: The selection of the articles was carried out according to the PRISMA flowchart and a table was created for the qualitative evaluation of the included articles. It was found 398 articles in the PubMed database and 375 in the Web of Science, 153 of which were coincident in both. Forty-six articles were selected for complete reading, 42 of which were excluded, and four articles were included in this review. Conclusion: The articles investigated in this review demonstrated that composite resin has a higher longevity in deciduous molars compared to glass ionomer cements. However, future clinical studies are needed to attest which material is better to restore them, since the resin modified glass ionomer cements showed satisfactory clinical survival rates.

TiF4 varnish protects the retention of brackets to enamel after in vitro mild erosive challenge

Abstract The effect of fluoride agents on the retention of orthodontic brackets to enamel under erosive challenge is little investigated. Objective: The aim of this study was to evaluate the effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) agents on the shear bond strength of brackets to enamel and on the enamel microhardness around brackets under erosive challenge. Methods: Brackets were bonded to bovine incisors. Five groups were formed according to fluoride application (n=10): TiF4 varnish, TiF4 solution, NaF varnish, NaF solution and control (without application). The specimens were submitted to erosive challenge (90 s cola drink/2h artificial saliva, 4x per day for 7 days). Solutions were applied before each erosive cycle and varnishes were applied once. Vickers Microhardness (VHN) was obtained before and after all cycles of erosion and the percentage of microhardness loss was calculated. Shear bond strength, adhesive remnant index and polarized light microscopy were conducted after erosion. The data were analyzed by ANOVA, Tukey, Kruskal-Wallis and Mann-Whitney U tests (α=0.05). Results: The %VHN had no statistically significant differences among the experimental groups. However, considering the comparisons of all groups with the control group, TiF4 varnish showed the highest protection from enamel demineralization (effect size of 2.94, while the effect size for the other groups was >2.4). The TiF4 varnish group had significantly higher shear bond strength compared to other groups. There was no difference among groups for adhesive remnant index. Polarized light microscopy showed higher demineralization depth for the control group. Conclusions: Application of NaF and TiF4 agents during mild erosive challenge minimized the enamel mineral loss around brackets, however only the experimental TiF4 varnish was able to prevent the reduction of shear bond strength of brackets to enamel.

Effects of erosive challenge on the morphology and surface properties of luting cements / Efeito do desafio erosivo na morfologia e propriedades de superfície de agentes cimentantes

Introduction: Few studies investigated the surface properties of luting cements after erosive challenge. Objective: To evaluate the surface roughness (Ra), Vickers hardness (VHN) and morphology of 4 luting cements after erosive challenge. Material and method: Twenty specimens of each cement were prepared (4×2mm) and divided into experimental (erosive challenge) and control (artificial saliva) groups (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) and Zinc phosphate (ZnP). The erosive challenge was performed by four daily erosive cycles (90s) in a cola drink and 2 h in artificial saliva over 7 days. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was analyzed by scanning electron microscopy (SEM). ANOVA, Tukey and Student-T tests were used (α=0.05). Result: After erosion, all luting cements had increase in Ra values and U200 and ZnP groups had the highest %VHN. After saliva immersion, only U200 and ZnP groups had significant increases in Ra values and there were no significant differences among the groups in %VHN. SEM analysis showed that Ketac and ZnP groups had rough and porous surfaces, and U200 group had higher resin matrix degradation than ARC group. Conclusion: Erosive challenge with a cola drink affected the surface properties of all luting cements.

Introdução: Poucos estudos investigaram as propriedades de superfície de cimentos após desafio erosivo. Objetivo: Avaliar a rugosidade da superfície (Ra), dureza Vickers (VHN) e morfologia de superfície de 4 cimentos após desafio erosivo. Material e método: Vinte amostras de cada cimento foram preparadas (4×2mm) e divididas em grupo experimental (desafio erosivo) e controle (saliva artificial) (n=10): Rely X U200 (U200); Rely X ARC (ARC); Ketac Cem Easy Mix (Ketac) e Fosfato de Zinco (ZnP). O desafio erosivo foi realizado com quatro ciclos erosivos diárias (90s) em bebida à base de cola e 2h em saliva artificial durante 7 dias. As leituras de Ra e VHN foram realizadas antes e após erosão. A porcentagem de perda de dureza (%VHN) foi obtida depois da erosão. A morfologia de superfície foi analisada por microscopia eletrônica de varredura (MEV). Foram utilizados testes de ANOVA, Tukey e T-Student (α=0,05). Resultado: Após a erosão, foi observado aumento dos valores de Ra em todos os cimentos testados, e os grupos U200 e ZNP tiveram a maior %VHN. Após imersão em saliva, apenas os grupos U200 e ZnP tiveram aumento significativo nos valores de Ra e não houve diferenças significativas entre os grupos quanto à %VHN. A análise em MEV mostrou que os grupos Ketac e ZNP apresentaram superfícies rugosas e porosas, e o grupo U200 apresentou maior degradação da matriz comparado ao grupo ARC. Conclusão: O desafio erosivo com bebida a base de cola afetou as propriedades de superfície de todos os cimentos.

Thickness and nanomechanical properties of protective layer formed by TiF4 varnish on enamel after erosion

Abstract The layer formed by fluoride compounds on tooth surface is important to protect the underlying enamel from erosion. However, there is no investigation into the properties of protective layer formed by NaF and TiF4 varnishes on eroded enamel. This study aimed to evaluate the thickness, topography, nanohardness, and elastic modulus of the protective layer formed by NaF and TiF4 varnishes on enamel after erosion using nanoindentation and atomic force microscopy (AFM). Human enamel specimens were sorted into control, NaF, and TiF4 varnish groups (n = 10). The initial nanohardness and elastic modulus values were obtained and varnishes were applied to the enamel and submitted to erosive challenge (10 cycles: 5 s cola drink/5 s artificial saliva). Thereafter, nanohardness and elastic modulus were measured. Both topography and thickness were evaluated by AFM. The data were subjected to ANOVA, Tukey's test and Student's t test (α = 0.05). After erosion, TiF4 showed a thicker protective layer compared to the NaF group and nanohardness and elastic modulus values were significantly lower than those of the control group. It was not possible to measure nanohardness and elastic modulus in the NaF group due to the thin protective layer formed. AFM showed globular deposits, which completely covered the eroded surface in the TiF4 group. After erosive challenge, the protective layer formed by TiF4 varnish showed significant properties and it was thicker than the layer formed by NaF varnish.

In vitro effects of erosive challenge on the surface properties of sealants

To assess in vitro the surface roughness (Ra), Vickers hardness (VHN) and surface morphology of resin and glass ionomer materials used for sealants after dynamic erosive challenge. Methods: Twenty specimens of each material were prepared and divided into experimental (erosive challenge) and control groups (n=10): Protect Riva (SDI), Opallis Flow (3M ESPE), Fluroshield (Dentsply), Filtek Z350 XT Flow (3M ESPE). The erosive challenge was performed 4 times per day (90 s) in cola drink and for 2 h in artificial saliva for 7 days. The control specimens were maintained in artificial saliva. Ra and VHN readings were performed before and after erosion. The percentage of hardness loss (%VHN) was obtained after erosion. The surface morphology was evaluated by scanning electron microscopy (SEM). The data were analyzed by ANOVA, Tukey and paired t tests (á=0.05). Results: After erosion and saliva immersion, there was an increase in Ra values for all groups and Riva group showed the highest Ra values. After erosive challenge, Riva and Filtek groups showed significant decrease in VHN values, but Filtek group showed the greatest %VHN. For all groups there was inorganic particle protrusion and matrix degradation after erosion visualized by SEM images. Conclusions: Erosive challenge affected the surface properties of all materials used as sealants, particularly in the Riva and Filtek groups...

Effect of water storage on microshear bond strength of four dental adhesive systems to dentin

AIM: To evaluate the microshear bond strength of 4 dental adhesive systems after 1 year-water storage. MATERIAL AND METHODS: The sample consisted of 120 cylinders of composite, obtained from 24 bovine incisors, which were divided into four experimental groups: G1-Scotchbond Multi-Purpose, G2-Single Bond 2, G3-Clearfil SE Bond, G4-Adper Easy One and two storage times in distilled water: T0 - 24h and T1 - 1 year. A bivariate analysis was performed using the ANOVA and Tukey test (α=0.05). Results were evaluated inter-and intra-group in both times. RESULTS: After 24 hours, G1T0 (39.68A ± 11.55) showed higher bond strength (MPa) followed by G2T0 (22.71B ± 4.07), G3T0 (18.94BC ± 7.29) and G4T0 (13.30C ± 3.94). After 1 year of storage only G1T1 (33.95A ± 6.35) and G3T1 (13.59BC ± 2.63) maintained the bond strength values (p ≥ 0.05), while G2T1 (10.62C ± 4.32) and G4T1 (4.49D ± 2.49) presented a decrease in this values. CONCLUSION: The hydrophobic two-step adhesive systems maintained the bond strength after 1-year water storage.

Protective effect of calcium nanophosphate and CPP-ACP agents on enamel erosion

The aim of this study was to assess the effect of different remineralizing agents on enamel microhardness (KHN) and surface topography after an erosive challenge. Forty-eight human enamel specimens (4 × 4 mm) were randomly assigned to 4 groups: control (no treatment), fluoride varnish, calcium nanophosphate paste and casein phosphopeptide-amorphous calcium phosphate paste (CPP-ACP). Both pastes were applied for 5 minutes, and fluoride varnish, for 24 h. Four daily erosive cycles of 5 minutes of immersion in a cola drink and 2 h in artificial saliva were conducted for 5 days. KHN readings were performed at baseline and after 5 days. The percentage of enamel hardness change (%KHN) was obtained after erosion. The surface topography was evaluated by atomic force microscopy (AFM). The data were tested using ANOVA, Tukey's and paired-T tests (p < 0.05). After an erosive challenge, there was no statistically significant difference between the control (96.8 ± 11.4 KHN / 72.4 ± 3.0 %KHN) and the varnish (91.7 ± 14.1 KHN / 73.4 ± 5.5 %KHN) groups. The nanophosphate group showed lower enamel hardness loss (187.2 ± 27.9 / 49.0 ± 7.9 %KHN), compared with the CPP-ACP group (141.8 ± 16.5 / 60.6 ± 4.0 %KHN), and both were statistically different from the varnish and the control groups. AFM images showed a rough surface for the control and the varnish groups, a non-homogeneous layer with globular irregularities for CPP-ACP, and a thick homogeneous layer for the nanophosphate group. None of the agents provided protection against the development of erosion; however, nanophosphate paste was able to reduce enamel surface softening after the erosive challenge.

Analysis by confocal laser scanning microscopy of the MDPB bactericidal effect on S. mutans biofilm CLSM analysis of MDPB bactericidal effect on biofilm

Since bacteria remain in the dentin following caries removal, restorative materials with antibacterial properties are desirable to help maintaining the residual microorganisms inactive. The adhesive system Clearfil Protect Bond (PB) contains the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) in its primer, which has shown antimicrobial activity. However, its bactericidal effect against biofilm on the dentin has been little investigated. Objective: The aim of this study was to analyze by confocal laser scanning microscopy (CLSM) and viable bacteria counting (CFU) the MDPB bactericidal effect against S. mutans biofilm on the dentin surface. Material and methods: Bovine dentin surfaces were obtained and subjected to S. mutans biofilm formation in BHI broth supplemented with 1% (w/v) sucrose for 18 h. Samples were divided into three groups, according to the primer application (n=3): Clearfil Protect Bond (PB), Clearfil SE Bond, which does not contain MDPB, (SE) and saline (control group). After the biofilm formation, Live/ Dead stain was applied directly to the surface of each sample. Next, 10 µL of each primer were applied on the samples during 590 s for the real-time CLSM analysis. The experiment was conducted in triplicate. The primers and saline were also applied on the other dentin samples during 20, 90, 300 and 590 s (n=9 for each group and period evaluated) and the CFU were assessed by colonies counting. Results: The results of the CLSM showed that with the Se application, although non-viable bacteria were detected at 20 s, there was no increase in their count during 590 s. In contrast, after the PB application there was a gradual increase of non-viable bacteria over 590 s. Conclusions: The quantitative analysis demonstrated a significant decrease of S. mutans CFU at 90 s PB exposure and only after 300 s of Se application. Protect Bond showed an earlier antibacterial effect than Se Bond.

Reabilitação Oclusal com Prótese Parcial Removível Provisória Tipo “Overlay” –Relato de Caso / Occlusal Rehabilitation with Overlay Provisional Removable Partial Denture – Case Report

Um planejamento adequado de uma reabilitação protética nãodeve imputar o restabelecimento da dimensão vertical deoclusão (DVO) às próteses novas, sob o risco do pacientenão se adaptar a uma nova condição, uma vez que énecessário um período mínimo para a readaptação a umanova DVO. Neste artigo realizou-se a reabilitação protéticacom próteses parciais removíveis provisórias (PPRs) do tipo“overlay” ou de recobrimento oclusal, previamente aotratamento definitivo, pois o paciente apresentou consideráveldiminuição da DVO, utilizando-se pra isso trêstécnicas de determinação da DVO. Conclui-se que a utilizaçãode próteses parciais removíveis provisórias é de grandeimportância no início do tratamento reabilitador, visando aadaptação do paciente a uma nova condição oclusal...

An appropriate design of a prosthetic rehabilitation shouldnot impute the restoration of occlusal vertical dimension (OVD)to new prostheses, at the risk of the patient does not adaptto a new condition, since a certain amount of time is oftennecessary for adaptation to a new OVD. This articleperformed prosthetic rehabilitation with an overlay provisionalremovable partial denture prior to definitive treatment becausethe patient showed a considerable decrease in the OVD.Three techniques for OVD determination were used. It ispossible to conclude that the use of interim removable partialdentures is of great importance at the beginning of therehabilitation treatment in order to adapt the patient to a newocclusal condition...

Higienização de Próteses Totais e Parciais Removíveis / Complete and Partial Removable Dentures Cleansing Methods

Este estudo tem o objetivo de fazer uma revisão de literaturasobre os materiais e métodos de higiene de prótesesdentárias parciais removíveis e de próteses totais,apresentando quais materiais e métodos de limpeza estãodisponíveis, relacionando suas vantagens e desvantagens.O profissional tem função de orientar e motivar o pacienteem relação à higienização da prótese e dos tecidos dacavidade bucal, já que o acúmulo de debris na superfícieinterna das próteses removíveis e das próteses totais facilitaa colonização de bactérias e fungos. Isto contribui para aevidenciação clínica e subclínica de diversos processospatológicos, como a estomatite protética. Dentre os meios dedesinfecção estão os mecânicos (escovas, microondas eultrassom), químicos (peróxidos alcalinos, hipocloritosalcalinos, ácidos, desinfetantes e enzimas) e associaçãoentre os métodos mecânicos e químicos. Os estudosdemonstram que somente as escovas não são suficientespara remoção completa do biofilme, e o uso de escovasduras podem desgastar a superfície da resina, deixando-amais porosa e com maior facilidade de acúmulo de biofilme.Pode-se concluir que para uma correta higienização daspróteses devemos associar métodos físicos e químicos,utilizar escovas compatíveis para a prótese e produtosquímicos de acordo com cada planejamento...

The purpose of this study is to perform a literature reviewabout materials and methods available for the hygiene ofcomplete and removable partial dentures, comparing thecleaning methods available, and describing their advantagesand disadvantages. It is a function of the dental surgeon toguide and motivate the patient regarding hygiene of theprosthesis and tissues of the oral cavity, since theaccumulation of debris on the inner surface of dentalprosthesis may facilitate colonization of bacteria and fungi.This contributes to the establishment of clinical and subclinicalpathologic processes, such as denture stomatitis. Amongthe means of disinfection are the mechanical (brushes,microwave and ultrasound), chemicals (alkali peroxides, alkalihypochlorites, acids, disinfectants, and enzymes) andassociation between the chemical and mechanical methods.Studies have shown that only dental brushes are notsufficient for complete removal of bacterial plaque and theuse of hard brushes can wear away the surface of theresin, leaving it more porous and easier to plaqueaccumulation. It can be concluded that proper cleaning of theprosthesis requires physical and chemical methods, usingcompatible brushes for the prosthesis and chemicalsaccording to each planning...

Pinos de fibra anatômicos: técnica clínica e benefícios mecânicos — relato de caso

Introdução: o emprego de pinos estéticos compostos por fibra de vidro tem sido cada vez mais estudado e os benefícios biomecânicos, além da possibilidade adesiva,tornam viável seu uso em várias situações clínicas. Estudos mostram que a perfeita adaptação às paredes do canal radicular é importante para melhorar as propriedades do conjunto dente-pino. Objetivo: apresentar a sequência técnica de um reembasamento de pino de fibra de vidro em canal amplo de um incisivo central fraturado coronalmente. Relato do caso: paciente do sexo masculino,12 anos de idade, apresentou-se com fratura oblíqua no dente 11 após acidente, atingindo a câmara pulpar.Após tratamento endodôntico, a obturação do canal radicular foi removida em preparo mecânico, resultando em necessidade de reembasamento do pino de fibra (Exacto#3, Angelus), que foi realizado com resina composta microhíbrida (Natural Look, DFL). O pino foi cimentado com adesivo convencional de três passos quimicamente polimerizado (Fusion Duralink, Angelus) e cimento resinoso autopolimeriável (Cement Post, Angelus), sendo posteriormente reconstruída a restauração da fratura dentária. Resultados: alcançou-se ótima resolução funcional e estética, com previsão de grande durabilidade clínica

Efeito da Partícula de Carga e do Tempo de Armazenamento sobrea Microdureza de Superfície de Compósitos Restauradores Estéticos / Effect of Load Particle and Storage Time on the Surface Microhardness of EstheticRestorative Composites

Objeti vo: Avaliar o efeito de diferentes tamanhos de partí culasde carga e diferentes tempos de armazenagem na durezasuperfi cial de três compósitos restauradores estéti cos.Método: Foram confeccionados 60 corpos-de-prova, emforma de pasti lhas, com 5mm de diâmetro e 2mm de altura,os quais foram divididos em seis grupos (n=10) de acordocom a resina avaliada: Filtek Z350 (3M/ESPE) com partí culasde tamanho médio classifi cado como nanoparti culado; FiltekZ250 (3M/ESPE) com partí culas de tamanho médio classifi cadocomo micro-híbrido; e Durafi ll (Heraeus-Kulzer) com partí culasde tamanho médio classifi cado como microparti culado. Asamostras foram armazenadas em água desti lada pelos períodosde 24h e 60 dias (37ºC) e, após cada período de armazenagem,submeti das ao teste de microdureza uti lizando-se um aparelhocom edentador do ti po Vickers pelo período de 45s e carga de50g. Os resultados (VHN) obti dos foram submeti dos à análiseestatí sti ca através dos testes de ANOVA e Tukey (α=0,05).Resultados: Os valores médios (±DP), no período de 24h,apresentados pelas resinas testadas foram de: Filtek Z250 –64,46 (±3,30); Filtek Z350 – 59,60 (±3,42); e Durafi ll – 21,69(±2,39). Após armazenagem pelo período de 60 dias os valoresmédios (±DP) apresentados foram de: Filtek Z250 – 71,07(±6,38); Filtek Z350 – 47,63 (±4,42); e Durafi ll – 23,72 (±3,50).Observou-se diferença signifi cante entre os grupos II, III,V e VI (p<0,005). Todavia, os grupos I e II não apresentaramsignifi cância entre si, mas diferiram dos demais grupos.Conclusão: O armazenamento em água desti lada e o tamanhomédio das partí culas de carga podem infl uenciar na microdurezade superfí cie de resinas compostas...

Objecti ve: To evaluate the eff ect of diff erent sizes ofload parti cles and diff erent storage ti mes on the surfacemicrohardness of three estheti c restorati ve composites.Method: Sixty disc-shaped specimens (5 mm diameter and 2mm high) were fabricated and divided into 6 groups (n=10)according to the evaluated resin: Filtek Z350 (3M/ESPE), withmedium-sized parti cles classifi ed as nanoparti culate; FiltekZ250 (3M/ESPE), with medium-sized parti cles classifi ed asmicro-hybrid; and Durafi ll (Heraeus-Kulzer), with medium-sizedparti cles classifi ed as microparti culate. The specimens werestored in disti lled water for 24 h and 60 days (37ºC) and, aft ereach storage period, they were subjected to the microhardnesstest using a Vickers indenter during 45 s using a 50 g load. Theresults (VHN) were subjected to stati sti cal analysis by ANOVAand Tukey’s test (α=0.05).Results: In the 24-hour period, the mean values (±SD) presentedby the tested resins were: Filtek Z250 – 64.46 (±3.30); FiltekZ350 – 59.60 (±3.42); and Durafi ll – 21.69 (±2.39). Aft er 60-daystorage, the mean values (±SD) presented by the tested resinswere: Filtek Z250 – 71.07 (±6.38); Filtek Z350 – 47.63 (±4.42);and Durafi ll – 23.72 (±3.50). There was stati sti cally signifi cantdiff erence between groups II, III, V and VI (p<0.005). However,groups I and II did not diff er signifi cantly from each other, butwere signifi cantly diff erent from the other groups.Conclusion: The storage in disti lled water and the size of theload parti cles can have infl uence on the surface microhardnessof estheti c composite resins...

Influence of powder/liquid ratio on the radiodensity and diametral tensile strength of glass ionomer cements

Clinicians tend to make reductions in glass ionomer power/liquid (P/L) ratios since some materials are difficult to mix and flow into small cavities, grooves or pits. In general, changing the P/L ratio decreases the physical and mechanical properties of conventional glass ionomer cements (GICs) and resin modified glass ionomer cements (RMGICs), but alterations seem to depend on their composition. OBJECTIVE: To determine the influence of P/L ratio on the radiodensity and diametral tensile strength (DTS) of glass ionomer cements. MATERIAL AND METHODS: There were 2 factors under study: P/L ratio (manufacturer's recommended P/L ratio and a 50 percent reduced P/L ratio), and materials (Vitro Molar, Vitro Fil, Vitro Cem conventional GICs and Vitro Fil LC, Ortho Glass LC RMGICs. Five 1-mm-thick samples of each material-P/L ratio were produced for radiodensity evaluation. Samples were x-ray exposed onto Digora phosphor plate and radiodensity was obtained using the software Digora for Windows 2.5 Rev 0. For DTS, five (4.0x8.0 mm) cylinder samples of each material were tested (0.5 mm/min). Data were subjected to one- and two-way ANOVA (5x2) followed by Tukey's HSD test, or Kruskal-Wallis and Dunn's method. For paired comparisons, t-test or Mann-Whitney test were used (α=0.05). RESULTS: There was a significant interaction (P=0.001) for the studied factors (materials vs. P/L ratio). Reduced P/L ratio resulted in significantly lower DTS for the RMGICs, but radiodensity was affected for all materials (P<0.05). CONCLUSIONS: Reduced P/L ratio affected properties of the tested glass ionomer cements. RMGICs were more susceptible to lower values of DTS, but radiodensity decreased for all materials following P/L ratio reduction.

Radiodensity evaluation of dental impression materials in comparison to tooth structures

In the most recent decades, several developments have been made on impression materials' composition, but there are very few radiodensity studies in the literature. It is expected that an acceptable degree of radiodensity would enable the detection of small fragments left inside gingival sulcus or root canals. OBJECTIVE: The aim of this study was to determine the radiodensity of different impression materials, and to compare them to human and bovine enamel and dentin. MATERIAL AND METHODS: Twenty-five impression materials, from 5 classes, were studied: addition and condensation silicones, polyether, polysulfides and alginates. Five 1-mm-thick samples of each material and tooth structure were produced. Each sample was evaluated 3 times (N=15), being exposed to x-ray over a phosphor plate of Digora digital system, and radiodensity was obtained by the software Digora for Windows 2.5 Rev 0. An aluminum stepwedge served as a control. Data were subjected to Kruskal-Wallis and Dunn's method (α=0.05). RESULTS: Different materials and respective classes had a different behavior with respect to radiodensity. Polysulfides showed high values of radiodensity, comparable to human enamel (p>0.05), but not to bovine enamel (p<0.05). Human dentin was similar only to a heavy-body addition silicon material, but bovine dentin was similar to several materials. Generally, heavy-body materials showed higher radiodensity than light-body ones (p<0.05). CONCLUSION: Impression materials' radiodensity are influenced by composition, and almost all of them would present a difficult detection against enamel or dentin background in radiographic examinations.