Effect of conditioning protocols and ultrasonic application of an infiltrant resin in white spot lesions

Abstract The aim of this study was to evaluate different conditioning protocols and sonic/ultrasonic application of an infiltrant resin (IR) in artificial white spot lesions (AWSL). the V/L surfaces of 48 molars were induced to an AWSL and divided in 6 groups, according to the conditioning protocols and application technique: 15% hydrochloric acid (HA) + manual application of the IR; HA + 37% phosphoric acid (PA) + manual application of the IR; HA + ultrasonic application (U) of the IR; HA + sonic application (S) of the IR; PA+HA+S; and PA+HA+U. For the Penetration Depth (PD), the crowns were etched with HA for 120s. The IR Icon® (DMG) was applied according to the manufacturer`s instructions. The crowns were dye penetrated (0.1% red fluorophore rhodamine B isothiocyanate for 12h) and bleached with 30% hydrogen peroxide for 12 h. The discs were immersed in a 50% ethanol solution, containing 100 µM of sodium fluorescein. The PD (in µm) was measured using confocal laser scanning microscopy (20x). The bond strength (BS) was performed by michoshear test (0.5 mm/min). Data were submitted to 2-way ANOVA and Tukey (α=0.05). For BS, the interaction was not significant (p>0.05). For PD, the main factors were significant (application - p<0.001; conditioning technique - p=0.003). The ultrasonic application showed the highest PD values. PA+HA presented higher results than HA. The sonic/ultrasonic applications and the use of phosphoric acid prior to hydrochloric acid improved PD of the infiltrant resin. Conditioning protocols or application techniques did not influence BS values.

Resumo: O objetivo deste estudo foi avaliar diferentes protocolos de condicionamento e a aplicação sônica/ultrassônica de uma resina infiltrante (RI) em lesões de mancha branca produzidas artificialmente (LMBA). As superfícies vestibulares/linguais de 48 molares foram induzidas à formação de LMBA e divididas em 6 grupos, de acordo com os protocolos de condicionamento e técnica de aplicação da resina infiltrante: ácido hidroclorídrico 15% (AH) + aplicação manual da RI; AH + ácido fosfórico 37% (AF) + aplicação manual da RI; AH + aplicação ultrassônica da RI (U); AH + aplicação sônica da RI (S); AF + AH + S; e AF + AH + U. para o grau de penetração (GP), condicionou-se as coroas com AH por 120 s. A RI Icon® (DMG) foi aplicada de acordo com as instruções do fabricante. As coroas foram coradas (rodamina B 0,1% por 12 h) e clareadas com peróxido de hidrogênio 30% por 12 h. os discos foram imersos em solução de etanol 50%, contendo 100 µM de fluoresceína sódica. O GP (em µm) foi mensurado por meio de microscopia confocal a laser (20´). A resistência de união (RU) foi calculada pelo teste de microcisalhamento (0,5 mm/min). Os dados foram submetidos ao teste ANOVA 2 fatores e Tukey (α=0,05). Para RU, a interação não foi significante (p>0,05). Para GP, os fatores principais foram significantes (técnica de aplicação - p<0,001; protocolos de condicionamento - p=0,003). A aplicação U mostrou os maiores valores de GP. AF+AH demonstrou resultados superiores ao grupo AH. As aplicações sônica/ultrassônica e o uso do ácido fosfórico antes do ácido hidroclorídrico aumentaram o GP da resina infiltrante. Os protocolos de condicionamento ou as técnicas de aplicação não influenciaram os valores de RU.

Bond strength values of fiberglass post to flared root canals reinforced with different materials

Abstract The aim of this study was to compare in vitro the bond strength (BS) between fiberglass posts and flared root canals reinforced with different materials. The roots of 48 premolars were endodontically treated. After one week, the root canals were prepared to simulate an oversized root canal, except for the positive control group (PCG), which was cemented with a prefabricated fiber post (PFP) compatible with the root canal size, simulating an ideal adaptation. The other samples (n=8/group) were used to test alternative restorative techniques for filling root canals: negative control group (NCG [PFP with a smaller diameter than of the root canal]), composite resin group - CRG, bulkfill group - BFG, self-adhesive cement group - SAG, and glass ionomer group - GIG. The posts were cemented and after 1 week, each root was sectioned transversely into six 1-mm thick discs and the push-out test was done to evaluate the BS. Data were analyzed by two-way repeated measures ANOVA and Tukey's tests (α=0.05). The highest BS value was observed for PCG. The NCG and the GIG groups showed the lowest BS values. Root reinforcement with conventional and bulk-fill composite resins showed the highest BS values; however, the bulk-fill resin was the only treatment able to maintain high BS values in all regions of the root canal. The self-adhesive cement showed intermediate results between CRG and GIG. Root reinforcement with bulk-fill composite resin is an effective option for flared root canals before cementation of a prefabricated fiber post.

Influence of different burs and acid ultrasonic agitation on the bonding of fiber posts to root dentin

Aim: The objective is to evaluate the influence of different burs used to prepare the root canal space and acid ultrasonic agitation on bond strength (BS) between glass fiber posts (GFP) and root dentin. Methods: After endodontic treatment, the root canal spaces of 36 extracted human canines were prepared, according to the rotary instrument used (n=18): carbide bur (CB), provided by the post manufacturer and a diamond bur (DB). In both groups, the fiber posts were cemented with the adhesive system Ambar and resin cement Allcem, following the manufacturer`s instructions. Previously to the cementation procedures, the groups were subdivided into 2 groups (n=9), according to the phosphoric acid application mode: conventional etching (CE) and active etching (AE), performed by ultrasonic tip, both for 15s. Before the cementation procedures and after the acid application, 1 root of each group was randomly selected for ultrastructural morphological evaluation by SEM. After 1 week of the cementation, 8 specimens per group were transversely sectioned into six 1-mm thick slices, the root canal regions (cervical, medium and apical) were identified and the push-out test was performed to evaluate BS. Data were analyzed by 3-way ANOVA and Tukey test (α=0.05). Results: The results showed that the cross-product interaction of all factors was significant (P=0.035). Higher bond strength values were obtained when a DB with conventional etching, instead of CB, was used to prepare the root post space. Conclusion: It may be concluded that the use of diamond burs with conventional etching yields high BS values in all root canal thirds

Effect of the Bis-Dimethylamino Benzydrol Coinitiator on the Mechanical and Biological Properties of a Composite

Abstract To examine the effect of the alternative coinitiator 4,4'bis dimethylamino benzydrol (BZN) in degree of conversion (DC), mechanical and biological properties of experimental composites. The coinitiator BZN was used in three concentrations (0.2, 0.5 and 1.2%), and the coinitiator DMAEMA was used as control at the same concentrations as above. The molar concentration of camphorquinone (CQ) and coinitiators was kept constant (1:1). The composites were manipulated and submitted to microhardness test (VHN), flexural and compressive strength (in MPa), elastic modulus (GPa), DC (FT-IR) and in vitro cytotoxicity (against 3T3 fibroblastic cells) of the experimental resins. Data were subjected to two-way ANOVA and Tukey post-test (α=0.05). The experimental composite resin with BZN showed higher DC values compared to control DMAEMA groups. For the mechanical properties, microhardness values were higher in BZN groups; flexural strength and elastic modulus were similar between all the groups. Compressive strength for groups BZN0.5 and DMAEMA0.5 were not statistically different, being the lowest values attributed to group BZN0.2. The experimental resins with BZN and DMAEMA were considered nontoxic against 3T3 fibroblasts. The inclusion of the coinitiator BZN in experimental composites was considered nontoxic against 3T3 fibroblast cells, without compromising DC and mechanical properties.

Resumo Analisar o efeito do co-iniciador alternativo 4,4'bisdimetilaminobenzidrol (BZN) no grau de conversão (GC) e nas propriedades mecânicas e biológicas de resinas compostas experimentais. O co-iniciador BZN foi utilizado em três concentrações (0,2, 0,5 e 1,2), e o co-iniciador DMAEMA como controle, nas mesmas concentrações acima. A concentração molar entre canforoquinona (CQ) e os co-iniciadores foi mantida constante (1:1). As resinas compostas foram manipuladas e submetidas aos testes de microdureza (VHN), resistência à compressão e flexural (em MPa), módulo de elasticidade (em GPa), GC (em %, por meio de espectroscopia micro-Raman e FTIR com KBr), citotoxicidade in vitro (frente às células fibroblásticas 3T3) das resinas experimentais. Os resultados foram submetidos ao teste ANOVA 1 fator e pós-teste de Tukey (α=0,05). As resinas compostas experimentais com o BZN apresentaram GC e propriedades mecânicas satisfatórias, além de serem consideradas atóxicas a fibroblastos 3T3. A inclusão do co-iniciador BZN à resina composta foi considerada não tóxica frente a células fibroblásticas 3T3 e sem comprometer o grau de conversão e as propriedades mecânicas da mesma.

Is the bonding of self-adhesive cement sensitive to root region and curing mode?

Abstract Objectives To evaluate the influence of two curing techniques on the degree of conversion (DC) of resin cements and on bond strength (BS) of fiber posts in different regions of root dentin. Material and Methods Twenty single-rooted premolars were endodontically treated, and the post spaces were prepared. The roots were randomly divided into two groups (n=10), according to the activation mode of the resin cement RelyX™ U200 (3M ESPE Saint Paul, MN, USA): conventional (continuous activation mode) and soft-start activation mode (Ramp). The posts (WhitePost DC/FGM) were cemented according to the manufacturer’s recommendations and, after one week, the roots were cross-sectioned into six discs each of 1-mm thickness, and the cervical, medium, and apical thirds of the root canals were identified. The DC was evaluated under micro-Raman spectroscopy and the BS was evaluated by the push-out test. The data were analyzed by two-way ANOVA and Tukey’s test (α=0.05). Results Neither the activation mode nor the root regions affected the DC of the resin cement. Higher BS was achieved in the soft-start group (p=0.036); lower BS was observed in the apical third compared to the other root regions (p<0.001). Irrespective of the activation mode and root region, the mixed failure mode was the most prevalent. Conclusion The BS of fiber posts to root canals can be improved by soft-started polymerization. The DC was not affected by the curing mode.

Investigação das propriedades mecânicas de cimentos resinosos duais convencionais e autoadesivos em macro e nanoescala / Investigation of mechanical properties of conventional and self-adhesive resin cements in macro and nanoscale

Objetivo: O objetivo desse estudo foi avaliar e comparar as propriedades mecânicas dos cimentos resinosos duais convencionais e autoadesivos em macro e nanoescala. Métodos: Foram confeccionados 15 espécimes de cada marca de cimentos resinosos, AllCem (FGM), RelyX ARC (3M/ESPE) e RelyX U200 (3M/ESPE), para cada teste realizado (flexão de três pontos, compressão e nanoindentação) de acordo com as instruções dos fabricantes. Os espécimes foram fotoativados com aparelho Optilux Demetron (Kerr) por 40 segundos e armazenados em frascos escuros a 37ºC por 24 horas. Foram obtidos os resultados de resistência flexural, resistência à compressão, dureza e de módulo de Young para os diferentes testes mecânicos. Os dados foram avaliados pelos testes ANOVA, múltiplas comparações de Tukey HSD para análise dos valores de resistência, dureza e módulo de elasticidade entre os diferentes cimentos resinosos e ANOVA dois critérios e múltiplas comparações de Games Howell para análise dos módulos de Young entre os diferentes experimentos. Resultados: Os resultados revelaram que o AllCem obteve os maiores valores de resistência flexural e compressão axial (129±22,01 MPa; 243,71±29,75, respectivamente) e o RelyX U200 os menores valores (82,35±19,83 MPa; 134,57±48,93 MPa, respectivamente). Os valores de dureza não diferiram entre os cimentos estudados. No teste de flexão os valores de módulo de Young não diferiram entre os cimentos resinosos. No teste de compressão axial o AllCem apresentou módulo de Young estatisticamente maiores que dos demais cimentos. Para nanoindentação AllCem e RelyX U200 apresentaram maiores valores de módulo de Young que RelyX ARC. Os valores de módulo de Young diferiram significativamente entre todos os experimentos (p<0.05). Conclusão: Os valores das propriedades dos cimentos resinosos podem ser influenciados pelo tipo de experimento (macro- ou nanoescala) realizado.(AU)

Aim: The aim of this study was to evaluate and compare the mechanical properties of conventional and self-adhesive dual resin cements in macroscale and nanoscale. Methods: Fifteen specimens of each brand of resin cement ­ AllCem (FGM), RelyX ARC (3M/ ESPE), and RelyX U200 (3M/ESPE) ­ were made for each test performed in this study (three point bending, compression, and nanoindentation) according to the manufacturer's instructions. The specimens were photoactivated with Optilux Demetron (Kerr) for 40 seconds and stored in the dark at 37°C for 24 hours. Subsequently, they were submitted to flexural strength and axial compression tests at a speed of 1 mm/min, as well as to the Berkovich nanoindentation test. The results of flexural strength, compressive strength, hardness, and Young's modulus were obtained for the different mechanical tests. Data were evaluated by ANOVA tests; multiple comparisons of Tukey HSD to analyze the values of strength, hardness, and Young's modulus among the different resin cements; and ANOVA two criteria and multiple comparisons of Games Howell to analyze the Young's modulus within the different experiments. Results: The results showed that AllCem obtained the highest values of flexural strength and axial compression (129±22.01, 243.71±29.75 MPa, respectively), while RelyX U200 presented the lowest values (82.35 ± 19.83, 134.57 ± 48.93 MPa, respectively). The hardness values did not differ among the studied cements. In the flexural test, the Young's modulus values did not differ between the resin cements. In the axial compression test, AllCem presented a Young's modulus that was statistically higher than the other cements. In the nanoindentation test, AllCem and RelyX U200 presented higher values for Young's modulus than RelyX ARC. Young's modulus values differed significantly among all experiments (p <0.05). Conclusion: The values of resin cement properties can be influenced by the type of experiment (macroscale and nanoscale) performed.(AU)

Active and Passive Application of the Phosphoric Acid on the Bond Strength of Lithium Disilicate

Abstract The objective of this study was to evaluate the effect of passive or active phosphoric acid (PA) application after hydrofluoric acid (HA) treatment on the microshear bond strength of lithium disilicate. Thirty ceramic discs were made with IPS Emax 2 (10 mm thick and 10 mm diameter). The specimens were divided into 3 groups, A: 9.6% HA application; AF: 9.6% HA application + cleaning with 37% PA in passive mode and AFF: 9.6% HA application + cleaning with 37% PA in active mode. For the microshear test, four tygons (0.9 mm diameter and 0.2 mm high) were filled with resin cement (RelyX Ultimate) and placed on the ceramic disks. After testing, the fracture modes were examined under scanning electron microscopy. Data were analyzed by one-way ANOVA and Tukey's post test (α=0.05). The bond strength values were significantly higher in Group AFF (11.0±2.5 MPa) compared with group A (8.1±2.6 MPa) (p<0.002). AF group was not statistically different (9.4±2.5 MPa) from Group A. It was concluded that the active application of 37% PA after 9.6% HA increases the microshear bond strength values between the resin cement and lithium disilicate ceramic.

Resumo O objetivo desse estudo foi avaliar o efeito da aplicação passiva ou ativa do ácido fosfórico após o tratamento com ácido hidrofluorídrico na resistência de união ao microcisalhamento entre cimento resinoso e dissilicato de lítio. Trinta discos foram confeccionados com IPS Emax 2 (10 mm de espessura e 10 mm de diâmetro). Os espécimes foram divididos em três grupos (A: aplicação do ácido hidrofluorídrico 9,6%; AF: aplicação do ácido hidrofluorídrico 9,6% + limpeza com ácido fosfórico 37% em modo passivo; AFF: aplicação do ácido hidrofluorídrico 9,6% + limpeza com ácido fosfórico 37% no modo ativo). Para o teste de microcisalhamento, quatro tygons (0,9 de diâmetro e 0,2 mm de altura) foram preenchidos com cimento resinoso (RelyX Ultimate) e dispostos sobre os discos de cerâmica. Após o teste, os modos de fratura foram examinados por microscopia eletrônica de varredura. Os dados foram analisados estatisticamente por ANOVA e pós-teste de Tukey (α=0,05). Os valores de resistência de união foram significativamente superiores para o grupo AFF (11,0±2,5 MPa), comparado ao grupo A (8,1±2,6 MPa) (p<0,002), mas este não estatisticamente diferente do grupo AF (9,4±2,5 MPa). Concluiu-se que a aplicação ativa do ácido fosfórico 37% após o uso do ácido hidrofluorídrico 9,6% aumenta a resistência de união entre o cimento resinoso e a cerâmica de dissilicato de lítio.

Effect of bleaching agents containing fluoride or calcium on enamel microhardness, roughness and permeability

To evaluate the effect of different in-office bleaching agents on the permeability, roughness and surface microhardness of human enamel. Methods: For evaluation of roughness and microhardness, 40 hemi-faces of 20 premolars were subjected to initial roughness (Ra parameter) and microhardness (VHN) measurements. Thirty-two premolar's crowns were used for permeability test. Then, all specimens were randomly divided into four groups: C - without bleaching (control), HP35 - bleaching with 35% hydrogen peroxide (HP), HPF38 - 38% HP+fluoride, HPC35 - 35% HP+calcium. Final roughness (FR) and microhardness (FM) measurements were evaluated. For permeability, the 32 crowns were immersed in 1% sodium hypochlorite (20 min) and silver nitrate solutions (2 h) and subjected to developing solution under fluorescent light (16 h). Three sections from the crowns were analyzed in light microscope (100x) to evaluate the scores of permeability: Score 0 - no tracer agent penetration; Score 1 - less than half the thickness of enamel penetration; Score 2 - tracer agent reaching half the enamel thickness; Score 3 - entire enamel depth penetration, without reaching dentin and Score 4 - tracer agent reaching dentin. For roughness and microhardness evaluation were used one-way ANOVA and Dunnet post-test for independent samples, and t test for paired samples. For permeability, the data were analyzed by Kruskal Wallis and Dunn tests. Results: A significantly higher permeability and surface roughness were observed in groups HP35, HPF38 and HPC35 compared to the C group, as well as decreased microhardness (p<0.05). Conclusions: All bleaching agents increased permeability and surface roughness, and decreased microhardness of human enamel; thus, the addition of fluoride or calcium was not beneficial...

Avaliação da liberação de flúor e da capacidade de recarga em diferentes cimentos de ionômero de vidro / Evaluation of the fluoride release and ability to recharge in different glass ionomer cements

Objetivo: Avaliar a liberação e a capacidade de recarga de flúor de diferentes cimentos de ionômero de vidro, durante a simulação de desafio cariogênico. Material e método: Foram confeccionados 12 corpos de prova para cada grupo experimental, com cimentos de ionômero de vidro convencionais - Maxxion R (FGM), Ketac Molar EasyMix (3M ESPE); cimento de ionômero de vidro modificado por resina - Vitrebond (3M ESPE), e resina composta, Filtek™ Z350XT (3M ESPE), como controle negativo. Os corpos de prova foram imersos alternadamente em sistema de ciclagem de pH, permanecendo 6 horas na solução de desmineralização e 18 horas na de remineralização, sendo mantidos em estufa a 37°C. Liberação de flúor foi verificada 1, 2, 7 e 14 dias antes e após a recarga com flúor, com eletrodo específico acoplado ao aparelho analisador de pH/fluoretos, calibrado a cada medição com soluções de fluoreto de sódio a 1 e 10 ppm, preparadas com TISAB II. Para leitura, foi adicionado 0,5 mL da amostra a igual volume de TISAB II. Recarga foi realizada com flúor neutro 2% por 4 minutos nas amostras, lavadas e imersas novamente nas soluções do sistema de ciclagem de pH. Os dados foram submetidos à análise de variância e ao teste de Tukey (α=0,05). Resultado: A liberação inicial de fluoreto (µgF/cm2) foi de 45,36; 37,49, e 26,35 para Maxxion R, Vitrebond e Ketac Molar EasyMix, respectivamente. Diferenças estatísticas significativas entre os materiais foram verificadas antes e após a recarga (p=0,001). Após a aplicação tópica de flúor, os cimentos de ionômero de vidro apresentaram capacidade de recarga de flúor. Conclusão: Cimentos de ionômero de vidro avaliados foram capazes de liberar flúor em soluções de ciclagem de pH e podem recarregar flúor através da aplicação tópica.

Objective: To evaluated the ability to fluoride release and recharge in the different glass ionomer cements during simulation of cariogenic challenge. Material and method: Twelve samples were made for each experimental group: conventional glass ionomer cements, Maxxion R (FGM), Ketac Molar EasyMix (3M ESPE); resin modified glass ionomer cement, Vitrebond (3M ESPE); and composite resin n Filtek™Z350XT (3M ESPE), negative control. The samples were immersed alternately in pH cycling method, remaining 6 hours in demineralization solution and 18 hours in remineralization solution and maintained at 37 °C. Fluoride release was measured 1, 2, 7, and 14 days before and after recharging with specific electrode coupled to the analyzer apparatus pH/fluoride, each measurement with calibrated solutions of sodium fluoride to 1 and 10 ppm, prepared with TISAB II. For reading was added 0.5 mL of sample to an equal volume of TISAB II. Recharging was made with neutral sodium fluoride to 2% for 4 minutes in the samples, washed and again immersed pH cycling solutions. Data were subjected to two-way ANOVA and Tukey's post-hoc test (α=0.05). Result: The initial fluoride release (µgF/cm2) was 45.36 ; 37.49 and 26.35 for Maxxion R, Vitrebond and Ketac Molar EasyMix, respectively. Significant differences between the materials before and after recharging were observed (p=0.001). After topical application of fluoride, both showed ability to recharge. Conclusion: The glass ionomer cements evaluated were capable of releasing fluoride in pH cycling solutions and may recharge through of a topical application.

Clinical Evaluation of the Whitening Effect of Over-the-Counter Dentifrices on Vital Teeth

This randomized clinical trial evaluated the whitening potential of commercially available toothpastes. Sixty patients were selected and randomly divided into 4 groups (n=15), according to the dentifrice used: GI (control) - Colgate Total 12, GII - Close-up White Now, GIII: Oral-B 3D White, GIV: Colgate Luminous White. Three daily brushings were performed for 2 to 3 min each, during a period of 15 days. Patients had the color of their teeth evaluated before and after the treatment by means of a spectrophotometer (Vita EasyShade - CIE L*a*b*). Data obtained from L values were analyzed by one-way ANOVA and t test. ∆E was also evaluated to calculate color alteration, by NBS criteria. Mean (standard deviation) of initial values were GI: 82.9 (4.9); GII: 83.9 (5.8); GIII: 83.9 (7.2); GIV: 86.4 (3.4) and final values were GI: 84.1 (6.3); GII: 84.6 (6.1); GIII: 84.2 (7.1); GIV: 88.2 (2.8). In conclusion, the dentifrices showed no lightening action on vital teeth, except for Colgate Luminous White; but according to NBS criteria, there was no noticeable visible change to the patients in any group.

Este estudo clínico randomizado avaliou o potencial clareador de cremes dentais disponíveis no mercado. Materiais e Métodos: Foram selecionados 60 pacientes, os quais foram divididos aleatoriamente em 4 grupos (n=15): GI - controle - Colgate Total 12; GII- Close-up White Now; GIII - Oral-B 3D White; GIV - Colgate Luminous White. Foram realizadas 3 escovações diárias pelo tempo de 2 a 3 minutos, durante um período de 15 dias. Os pacientes tiveram a cor de seus dentes avaliados antes e após o término do tratamento através do espectrofotômetro Vita EasyShade (escala CIE L*a*b*) Os valores de L* foram analisados por ANOVA um fator para amostras independentes e teste t para amostras pareadas. ∆E também foi calculado para verificar alterações de cor, de acordo com os critérios NBS. A média (desvio padrão) dos valores iniciais foi: GI: 82,9(4,9); GII: 83,9(5,8); GIII: 83,9(7,2); GIV: 86,4(3,4); e os valores finais - GI: 84,1(6,3); GII: 84,6(6,1); GIII: 84,2(7,1); GIV: 88,2(2,8), concluindo-se que os dentifrícios analisados neste estudo não apresentaram ação clareadora sobre dentes vitais, com exceção do dentifrício Colgate Luminous White, porém de acordo com os critérios do NBS, não houve alteração visível a olho nu para nenhum dos grupos.

Effect of finishing and polishing on surface roughness of composite resins after bleaching

AIM : To evaluate the influence of finishing and polishing techniques on the surface roughness of two composite resins (CRs) subjected to bleaching procedure. METHODS : Forty-eight CR specimens were divided into six groups (n=8). For G1 to G3, a microhybrid CR (Opallis; FGM) was used, and G4 to G6, received a nanohybrid CR (Brilliant NewLine; Coltène/Whaledent). All specimens were subjected to bleaching procedure with 35% hydrogen peroxide (two 45-min applications, with a 5-day interval). The surface roughness of all specimens was evaluated before and after the bleaching and/or finishing/polishing (Ra parameter) by a roughness meter. After bleaching, the groups were subjected to finishing and polishing procedures: G2 and G5 - felt discs + diamond pastes; and G3 and G6 - silicon rubber tips. The control groups (G1 and G4) had no finishing or polishing treatment after bleaching. Data were analyzed by ANOVA and Tukey's post-test, and t test for paired samples (a=0.05). RESULTS : bleaching treatment increased Ra values for the nanohybrid CR specimens, but both finishing/polishing techniques were able to reduce these values; for the microhybrid specimens, only finishing/polishing with silicon rubber tips decreased the roughness values. CONCLUSIONS : For both microhybrid and nanohybrid CRs, the silicon rubber tips were effective to reduce the surface roughness after bleaching procedure...

Efectos del método de aplicación y tiempo de fotopolimerización de un nuevo adhesivo autograbador / Effects of application method and curing time of a new self-etching adhesive

Evaluar el método de aplicación y tiempo de fotopolimerización de dos sistemas adhesivos autograbadores sobre esmalte. Materiales y Métodos: Fueron utilizados 30 molares, los cuales fueron divididos en 8 grupos de 10 muestras cada uno a los cuales se les aplico dos tipos de adhesivos autograbadores (1 Adhese y 2 Unniversal Single bond) de manera activa y pasiva con diferentes tiempos de fotopolimerización para evaluar la resistencia de unión de estos adhesivos autograbadores, después de la conformación de los tygon fue llevado a microcizallamiento. Resultados: Mostraron que la extensión de irradiación de luz para los adhesivos (1 Adhese y 2 Universal Single bond) no dio diferencia significativamente independientemente del tipo de aplicación (p<0.005). En cuanto al tipo de aplicación si hubo diferencia significativa para los dos adhesivos (p<005). Conclusiones: La aplicación activa aumenta los valores de resistencia de unión en adhesivos autograbadores de un paso y dos pasos en esmalte.

Introduction: To evaluate the method of application and curing time of two adhesive systems on enamel-etching. Materials and Methods: The study involved 30 molars, which were divided into 8 groups of 10 samples each in which we applied two types of self-etching adhesives (1 AdheSE and 2 Universal Single bond) actively and passively with different times of photopolymerization to evaluate the bonding strength of these etching adhesives, after forming of the tygon microshear was carried. Results: showed that the extension of light for adhesives (1 AdheSE Universal Single bond and 2) did not differ significantly regardless of the type of application (p>0.005). As for the type of applications if no significant difference for the two adhesive (p<0.005). Conclusions: The active application increases the values of bond strength of self etching adhesives one step and two steps in enamel.

Shrinkage stress of resin composites: effect of material - sistematic review / Tensão de contração de resinas compostas: efeito da composição do material - revisão sistemática

The longevity of resin depends on its binding between the margin of restorations and the polymer, and one factor that influences this aspect is the shrinkage stress. Thus, the working group presents the following systematic review thatverifies the influence of composite resin composition on shrinkage stress. The following electronic databases were searched: MEDLINE (via Ovid and PubMed - 2004 to January 2014), with the keywords: shrinkage stress, degree of conversion, resin composite. For shrinkage stress,, the best results were found when the BISGMA monomer was used and for the inorganic composition, an inverse relationship was observed: the increased inorganic filler content decreases shrinkage stress.

A longevidade de resina depende da sua ligação entre a margem de restaurações e o polímero, e um fator que influencia a este aspecto, é a tensão de contração. Assim, o grupo de trabalho faz a seguinte análise sistemática para verificar a influência da composição das resinas composta na tensão de contração. As seguintes bases de dados eletrônicas foram pesquisadas: MEDLINE (via PubMed e Ovídio - de 2004 a janeiro de 2014), com as palavras-chave: estresse de contração, grau de conversão, resina composta. Para tensão de contração, os melhores resultados foram encontrados quando o monômero BISGMA foi utilizada e para a composição inorgânica, uma relação inversa foi observada: o aumento do teor de carga inorgânica diminui estresse de contração.

Influence of sandblasting distance on enamel and ceramic structure bond strength / Influência do jateamento na estrutura cerâmica e esmalte, alterando a distância na resistência de união

Objetive: The purpose of this study was to evaluate the influence of sandblasting distance on ceramic and enamelbond strength. Material & Methods: Sixtythird molars were selected, enamel surfaces were ground flat with wet 600 - 2000 grit aluminum oxide abrasive papers and polished with three, one, and one-fourth micrometer-grit diamond pastes. On hundred and twentylithium disilicate-based core ceramic discs (2 mm diameter; 1 mm thickness) were also obtained and further divided into 7 groups [Group C, no sandblasting, Group SB-E(5-10) enamel sandblasting - 5 and 10 mm of distance, Group SBC(5-10) ceramic sandblasting 5 mm and 10 mm of distance, Group SB-EC(5-10) enamel and ceramic sandblasting 5 mm and 10 mm of distance]. After treatments,shear and Atomic Force Microscopy (AFM) tests were performed.Data were analyzed by Statistic Tests of normality, one-way ANOVA and Tukey post-test (α: 0.05). Results: Group C presented the highestbond strength values(59.2 ±12.5), while group SB-E 5 mm showed the lowest values (21.7 ± 08.8) (p < 0.005). Conclusion: The use of sandblasting treatment of enamel surface at 5mm distance decreases the bonding strength to shear.

Objetivo: o objetivo do estudo foi avaliar influência do jateamento na estrutura cerâmica e esmalte sob resistência de união, mudando a distância. Materiais e Métodos: 60 terceiros molares, foram selecionados, superfícies de esmalte foram planificadas com lixa com grão 600 - 2000 lixas e polido com pastas de diamante de um grão -micrômetro. Obtidos 120 discos cerâmica em dissilicato de lítio de (2 mm de diâmetro e 1 mm de espessura), dividido em sete grupos [Grupo C, não jateamento, Grupo SB-E (5-10) esmalte jateamento 5 e 10 mm, Grupo SB -C (5-10) de jacto de areia cerâmica 5 mm e 10 mm, Grupo SB-CE (5-10) e esmalte cerâmico areação 5 milímetros e 10 mm], depois foi realizado o microcisalhamento e a microscopia de forca atômica (AFM), estatística como Teste de Normalidade , após análise de variância one-way e teste de Tukey (α: 0,05). Resultados: A força do grupo C apresentou maiores valores de resistência de união (59,2 ± 12,5), o grupo SB-E 5 mm (21,7 ± 08,8) (p < 0,005), o grupo SB-E10 (53,6 ± 14,3). Conclusão: o uso de jateamento tratamento da superfície do esmalte de 5 mm, de 20 s diminui a força de ligação de microcisalhamento.

Utilização de dentes humanos: aspectos éticos e legais / Human teeth use: ethical and legal aspects

O reconhecimento da importância do elemento dental como órgão humano é um fato muitas vezes negligenciado ou desconsiderado pela maioria dos odontólogos e por alguns profissionais vinculados à pesquisa científica, que utilizam grandes quantidades de dentes humanos em seus trabalhos, e por acadêmicos dos cursos de Odontologia. O presente estudo tem como propósito rever os aspectos éticos e legais envolvidos na utilização de dentes humanos por todos os envolvidos, sejam eles pesquisadores, professores e/ou alunos, promovendo assim um uso racional desses órgãos, o que vem sendo possível com a criação de Bancos de Dentes nas universidades. Diante do exposto, torna-se necessária a existência de um vínculo entre o Banco de Dentes e o Comitê de Ética da Instituição em que este se encontra, a fim de que se estabeleçam, desde o início de sua organização, diretrizes e normas de funcionamento conjuntas, visando ao cumprimento da legislação vigente.

The perception of the dental element as a human organ is neglected and disregarded many times by most of the dentists that use a great amount of human teeth in their works, by some of the professionals linked to scientific research, by professors and also by academics of dentistry courses. The main goal of this study is to review in the literature, the ethical and legal aspects involved in the use of human teeth in universities, demonstrating that that perception should be implicit in all its users, whether researchers, professors and/or students, resulting in a rational use of those organs, such as is possible with the creation of Bank of Teeth in universities. Facing the foregoing, it is necessary the existence of a link between the Bank of Teeth and the Ethics Institutional Committee of the university, in order to be establish guidelines, rules, standards and mode operations since the beginning of the bank organization, aimed at compliance with current legislation.

Effects of zirconia nanoparticles addition to experimental adhesives on radiopacity and microhardness

AIM: To evaluate the radiopacity and microhardness (KHN) of experimental dental adhesives (EX). The experimental adhesive resins of the present study were formulated based on the simplified adhesive system Ambar (FGM). METHODS: Five EX with different concentrations of zirconia nanoparticles [0(EX0), 15(EX15), 25(EX25), 30(EX30) e 50%(EX50)] were incorporated in a UDMA/HEMA adhesive (control). Adper Single BondTM 2 (SB, 3M ESPE) was used as a commercial reference. For the radiopacity (n=5), KHN (n=5), adhesive specimens were fabricated using a stainless steel mold. Data were submitted to one-way ANOVA and Tukey's test (α=0.05). RESULTS: The filler addition on the EX showed radiopacity similar to enamel and higher than SB. The EX25, EX35 and EX50 showed higher KHN values when compared to the commercial SB. EX25, EX35 and EX50 showed higher KHN values when compared to the commercial SB. CONCLUSIONS: The results of the present investigation suggest that the addition of zirconia nanoparticles seems to be a good alternative to produce radiopaque adhesives with increased microhardness.

Evaluation of human enamel permeability exposed to bleaching agents

Aim: To evaluate the human enamel permeability after different external bleaching techniques.Methods: The coronal portions of 20 maxillary human incisors were covered with an acidresistant varnish, except the labial surface, to prevent dye penetration of silver nitrate. Thespecimens were divided randomly into four groups (n=5) according to the bleaching treatments:Group 1 (G1) - without bleaching agent (control group), Group 2 (G2) - 35% hydrogen peroxide(HP) – one session of three 10-min applications, Group 3 (G3) - 35% HP – 2 sessions of three10-min applications, and Group 4 (G4) - 6% HP – 14 days (1h/day). G1 was exposed to artificialsaliva only and in the other groups the bleaching agents were applied following the manufacturers’recommendations. After bleaching, teeth were immersed in a 50% silver nitrate solution for 2 hand photodeveloped for 16 h. Then, three longitudinal slices of each tooth were photographedby an optical microscope (100x). The degree of dye penetration was analyzed in the middle thirdof the dental crowns using a 0 to 4 score system (0= no dye penetration, 1= less than half theenamel thickness, 2= half of the enamel thickness, 3= full extent of enamel without reaching thedentin, and 4= tracer agent reaching dentin). The data were analyzed statistically by the Kruskal-Wallis and Dunn tests (α=0.05). Results: The median (1st/3rd interquartiles) ranges were: G1:0(0/0), G2: 2(2/3), G3: 3(3/3) and G4: 3(3/3). G2, G3 and G4 showed significantly higher dyepenetration compared with G1 (p=0.0017). Conclusions: The use of bleaching agents increaseddental enamel permeability, regardless of the bleaching technique.

Efeito do clareamento na susceptibilidade ao manchamento de uma resina composta / Effect of bleaching on staining susceptibility of a composite resin

Objetivo: verificar o efeito do clareamento (caseiro e em consultório) na susceptibilidade ao manchamento de uma resina composta e imersão em soluções corantes. Trinta espécimes de resina composta microhíbrida sofreram avaliação de cor inicial (Vita EasyShade) e aleatoriamente divididos em 6 grupos G1: sem clareamento, com imersão em café; G2: sem clareamento, com imersão em vinho; G3: clareado com peróxido de carbamida 10% (PC 10%) e imersão em café; G4: clareado com PC 10% e imersão em vinho; G5: clareado com peróxido de hidrogênio 35% (PH 35%) e imersão café e G6: clareado com PH 35% e imersão em vinho. Em seguida, houve avaliação final de cor. Os resultados foram analisados por ANOVA 2 fatores e Pós-teste de Tukey (α=0,05). Foram avaliados valores de L (luminosidade), sendo as médias (desvio-padrão) dos valores iniciais - G1: 88,22(1,62); G2:86,76(0,86); G3:82,52(2,90); G4:84,72(1,24); G5:85,64(1,92); G6:86,30(1,13), e os valores finais: G1: 78,32(2,24); G2: 76,46(1,61); G3: 74,60(0,92); G4: 65,00(3,97); G5: 75,56(1,76); G6: 72,48(4,69). Os valores de ΔE também foram calculados (critérios do NBS). Conclusão: a resina composta, submetida ao clareamento, caseiro sofreu maior alteração de cor quando imerso em vinho tinto, comparado aos demais grupos.

Objective: to evaluate the effect of at-home and in-office bleaching on staining susceptibility of a resin composite with immersion in staining solutions. Thirty specimens of a microhybrid composite were first evaluated with a spectrophotometer (Vita Easyshade), and randomly divided into 6 groups: G1: no bleaching, immersion in coffee; G2: no bleaching, immersion in red wine; G3: bleaching with 10% carbamide peroxide (PC10%) and immersion in coffee; G4: bleaching with PC10% and immersion in wine; G5: bleaching with 35% hydrogen peroxide (PH35%) and immersion in coffee; G6: PH35% and immersion in wine. The final color was evaluated for all groups. Color change values (CIELab), by means of L values - luminosity - were evaluated and statistically analyzed by ANOVA and Tukey's post-test. Results: means(standard-deviation) for initial L values were: G1:88.22(1.62); G2:86.76(0.86); G3:82.52(2.90); G4:84.72(1.24); G5:85.64(1.92); G6:86.30(1.13), e final L values were: G1:78.32(2.24); G2:76.46(1.61); G3:74.60(0.92); G4:65.00(3.97); G5:75.56(1.76); G6:72.48(4.69). ΔE values were also calculated, according to NBS criteria. Conclusion: there was an increased staining susceptibility of the resin composite submitted to at-home bleaching when immersed in red wine, compared to the another groups, by means of luminosity.

Laminados cerâmicos minimamente invasivos / Minimally invasive porcelain laminate veneers

As facetas diretas em resinas compostas podem ser indicadas para solucionar diversos problemas estéticos, como diastemas, modificações de forma, posição, cor e textura dos dentes anteriores, porém, este material é suscetível ao desgaste e à alteração na coloração, limitando assim, o resultado estético ao longo do tempo. Para compensar tais limitações, foram então propostas restaurações indiretas, tais como laminados cerâmicos. O aperfeiçoamento nas propriedades físicas e mecânicas desses materiais, associado à evolução dos sistemas adesivos e cimentos resinosos, promoveram uma adequada união da cerâmica à estrutura dentária, que proporcionou um aumento na longevidade e desempenho clínico desta modalidade de restauração

Resin composite veneers can solve many aesthetic problems, such as diastema, alterations in shape, position, color and texture of the anterior teeth, but this material is susceptible to wearing and discoloration, limiting the aesthetic result. To compensate for these limitations, indirect restorations, such as porcelain laminate veneers were proposed. The improvement and development in the physical and mechanical properties of ceramic systems, associated with the adhesive systems and resin cements, have resulted in an adequate bonding to tooth structure and ceramics, and thereby increasing the longevity and clinical performance of this type of restoration

Efeito de diferentes agentes clareadores de uso caseiro na microdureza superficial de resinas compostas: microhíbrida X nanohíbrida / Effect of different at-home bleaching agents in microhardness surface of resin composites: microhybrid X nanohybrid

Avaliou-se o efeito de agentes clareadores de uso caseiro na microdureza de resinas compostas (RC) microhíbrida e nanohíbrida. Foram confeccionados 30 corpos-de-prova (cp), divididos em seis grupos (n=5). Os grupos G1 a G3 utilizaram RC microhíbrida (Opallis), e os grupos G4 a G6, RC nanohíbrida (BrilliantNewLine). Os agentes clareadores utilizados foram: peróxido de hidrogênio 6% (PH) (White Class Cálcio) e peróxido de carbamida 16% (PC) (Whiteness Perfect). Após a confecção dos cp, o clareamento foi realizado: G1 e G4: grupo controle sem agente clareador, G2 e G5: PH - 28 dias, G3 e G6: PC - 28 dias, de acordo com as recomendações dos fabricantes. Em seguida, o teste de microdureza foi realizado. Os dados obtidos foram analisados por ANOVA e Tukey (5%). Os resultados de microdureza (HV) e desvio-padrão foram: G1-26,56 ± 3,9, G2-25,98 ± 3,3 e G3-24,94 ± 4,4; G4-27,24 ± 3,3; G5-32,02 ± 6,4 e 37,72 G6- ± 8,1. O único grupo que apresentou diferenças significativas para os outros foi o G6 (p <0,05), mas não diferiu significativamente em relação ao G5 (p = 0,0058). Concluiu-se que o uso de agentes clareadores de uso caseiro não afetou negativamente a microdureza das resinas compostas testadas.

It was evaluated the effects of home bleaching agents on microhardness of microhybrid and nanohybrid composite resins. 30-of-body were made and divided into 6 groups (n=5). The groups G1 to G3 used a microhybrid CR (Opallis), while groups G4 to G6 used a nanohybrid CR (BrilliantNewLine). The bleaching agents used were: 6% hydrogen peroxide (PH) (White Class Cálcio) and 16% carbamide peroxide (PC) (Whiteness Perfect). After the specimens were prepared, the bleaching was realized as follows: G1 and G4: control group without bleaching agent, G2 and G5: PH - 28 days, G3 and G6: PC - 28 days, in accordance with the manufacturer's recommendations. After it, the microhardness test was performed. The data were statistically analyzed by ANOVA and Tukey's tests (5%). The results of microhardness (HV) and standard deviation of each group were: G1- 26.56±3.9; G2- 25.98±3.3; G3- 24.94±4.4; G4- 27.24±3.3; G5- 32.02±6.4 and G6- 37.72±8.1. The only group that showed significant differences to the anothers was the G6 (p<0.05), but did not differ significantly in relation to G5 (p=0.0058). It was concluded that the use of home bleaching agents didn't affect negatively the microhardness of the composite resins tested.