Two-year randomized clinical trial of different restorative techniques in non-carious cervical lesions and MMP activity in gingival crevicular fluid.

OBJECTIVES: To evaluate different restorative techniques for non-carious cervical lesions (NCCLs) and the activity of matrix metalloproteinases (MMPs) in gingival crevicular fluid. MATERIALS AND METHODS: Two hundred restorations were performed in 50 patients using resin composite restorative system without (I) and with selective enamel conditioning (II) and resin-modified glass-ionomer cement without (III) and with EDTA pretreatment (IV). Gingival crevicular fluid samples were collected in 15 patients. Restorations were evaluated using USPHS criteria at baseline and after 2 years. Percentages of MMP activity were assessed by zymography as a surrogate outcome. Equality tests of two proportions, logistic regression analysis, survival analysis, ANOVA repeated measures, and Fisher tests were used. RESULTS: No differences in clinical performance were found among groups. Group I had lower retention at 2 years than at baseline. Decreased alpha scores for marginal integrity and marginal discoloration were observed for all groups after 2 years. MMP-2 decreased after 1 year, and its activity increased back to the initial level after 2 years, mainly for groups I, II, and III. MMP-9 increased after 1 year, and it was reduced to the initial level after 2 years, mainly for group I. CONCLUSIONS: All restorative techniques performed similarly in NCCLs after 2 years with initial marginal defect alterations. MMP-2 reestablished its initial levels after 2 years, and MMP-9 had few alterations over time in crevicular fluid. Clinical relevance The different restorative techniques are equally successful in NCCLs after 2 years of clinical functioning and have similar effects on MMPs present in crevicular fluid.

Sodium trimetaphosphate combined to calcium as a strategy to improve dentin-bonding interface / Trimetafosfato de sódio associado ao cálcio como uma estratégia para melhorar a interface adesiva da dentina

Objective: The aim of this study was to evaluate the effect of STMP as biomimetic analog of dentin matrix on the dentin bond strength submitted to artificial cariogenic challenge over time. Material and Methods: The total number of teeth used in the experiment was 60 teeth, which were divided into 6 groups (n = 10). Of these total amount, 10 teeth were not submitted to the artificial cariogenic challenge (ACC), serving as control group (Sound Dentin - SD) while the other 50 were submitted to an ACC (7d/37ºC), being treated with treatment solutions according to each group: SD- deionized water/sound dentin, CD- deionized water/ artificial caries dentin, GIII- STMP, GIV- STMP + Ca(OH)2, GV- STMP + NaF, and GVI- NaF. After treatments (24h), the specimens were restored (Adper Single Bond Universal + Filtek Z250), to obtain resin­dentin sticks with a cross sectional area of 0.8mm2, approximately. Two-third of these sticks were stored in artificial saliva (37°C) for analyzes after 6 and 12 months. The 1/3 remains were subjected to µTBS test (baseline). Data were analyzed by two-way ANOVA and Tukey tests (p<0.05). Results: In general, the highest µTBS values were obtained in sound condition (SD), while the artificial caries condition (CD) determined minimum values. Groups treated with NaF (with or without STMP- GV and GVI) were not able to improve adhesion over time. Only the use of STMP + Ca(OH)2(GIV) improved the µTBS compared to the others caries-challenged dentin after 1 year. The adhesive failure pattern was predominant in all time. Conclusion: The use of the STMP associated with Ca(OH)2 seems to be a viable therapeutic strategy conciliating the biomimetizing capacity to the adhesive process satisfactorily even its performance is not superior to initial condition (AU)

Objetivo: O objetivo deste estudo foi avaliar o efeito do STMP como análogo biomimético da matriz dentinária na resistência de união à dentina submetida a desafio cariogênico artificial ao longo do tempo. Material e Métodos:foram utilizados um total de 60 dentes neste experimento, os quais foram divididos em 6 grupos (n = 10). Desse total, 10 dentes não foram submetidos ao desafio cariogênico artificial (DCA), servindo como grupo controle (Dentina Hígida - DH) enquanto os outros 50 foram submetidos ao DCA (7d / 37ºC), sendo tratados com soluções de tratamento específicas para cada grupo: DH- água deionizada / dentina hígida, DC- água deionizada / dentina submetida ao DCA, GIII- STMP, GIV- STMP + Ca(OH)2, GV- STMP + NaF e GVI- NaF. Após os tratamentos (24h), os corpos-de-prova foram restaurados (Adper Single Bond Universal + Filtek Z250), para obtenção de palitos de resina-dentina com área transversal de aproximadamente 0,8mm2. Dois terços desses palitos foram armazenados em saliva artificial (37°C) para análises após 6 e 12 meses. Os outros 1/3 foram submetidos ao teste µTBS (baseline). Os dados foram analisados por ANOVA a dois fatores e testes de Tukey (p <0,05). Resultados:Em geral, os maiores valores de µTBS foram obtidos em condição hígidas (DH), enquanto a condição subtmetidas ao DCA determinou os menores valores. Os grupos tratados com NaF (com ou sem STMP associado -GV e GVI) não foram capazes de melhorar a resistência de união, ao longo do tempo. Somente o uso de STMP + Ca (OH)2(GIV) melhorou o µTBS em comparação com as outras condições desafiadas por cárie após 1 ano. O padrão de falha adesiva foi predominante em todos os tempos. Conclusão: O uso do STMP associado ao Ca (OH)2 parece ser uma estratégia terapêutica viável conciliando a capacidade biomimetizante ao processo adesivo de forma satisfatória mesmo que seu desempenho não seja superior à condição inicial.(AU)

MDP-based universal adhesive system irradiated with Er,CR:YSGG: Analysis of its performance up to 6 months.

This study aimed to analyze the interaction of a MDP-based universal dentin bonding system (DBS) with Er, Cr: YSGG laser irradiation, measuring the microtensile bond strength to dentin over a six-month period. The experimental design involved three factors: DBS (Adper Scotchbond Universal; Clearfil SE Bond, Adper Scotchbond Multipurpose and Adper Single Bond 2), laser (Control and Er, Cr: YSGG), and time (initial- 7 days and 6 months). Eighty dentin samples from molars were prepared (n=10) with laser irradiation after primer and DBS application. After 7 days, were subjected to micro tensile bond strength test. The data were analyzed by three-way ANOVA and Tukey tests (p<0.05). Both DBS and laser significantly affected the bonding performance and their interaction was statistically significant (p=0.0194). The self-etching mode of the MDP-based universal DBS maintained the bond strength on dentin irradiated with ER, Cr: YSGG after 6 months, while bonding with all other DBS deteriorated.

Performance of MDP-based system in eroded and carious dentin associated with proteolytic inhibitors: 18-Month exploratory study.

The aim of this study was to explore the impact of the interaction between an MDP-based universal adhesive system in etch-and-rinse mode and two proteolytic inhibitors on the longevity of restorations bonded to artificially-affected-dentin substrates. 90 sound human third molars were randomly distributed into three groups according to the substrate: N-no challenges-control (stored in artificial saliva), ACD-artificial caries dentin (6 h DE + 18 h-RE/5 days + 48 h RE) and ERO-artificial erosion dentin (3 × 5 min/5 days with orange juice). They were further redistributed according to dentin pretreatment: W- water (control), CHX-2% digluconate chlorhexidine and E64- 5 µM E64-Trans-Epoxysuccinyl-L-Leucylamido-(4-guanidino) butane, which resulted in the following 9 groups (n = 10): N-W, N-CHX, N-E64, ACD-W, ACD-CHX, ACD-E64, ERO-W, ERO-CHX and ERO-E64. All specimens were restored with Adper Single Bond Universal (Etch-and-rinse mode)/Filtek Z250. Sticks (0.64 mm2) were obtained and subjected to microtensile test (µTBS) in a universal testing machine at 0.5 mm/min for 7-days, 6 and 18-month analyses. Failure modes were classified using optical microscopy (40X). Data were statistically analyzed by three-way ANOVA and Tukey tests (p < 0.05). All individual factors (p < 0.0001) and interaction between factors were statistically significant (substrate X pretreatment (p = 0.00093); substrate X time (p = 0.01035) and pretreatment X time (p = 0.0035). Caries-affected substrate was the most compromised one, disregarding the pretreatment. CHX was mostly affected compared with E64 up to 18 months, possibly due to its calcium-dependent mechanism.

Profile of a 10-MDP-based universal adhesive system associated with chlorhexidine: Dentin bond strength and in situ zymography performance.

The incorporation of functional monomers and proteolytic inhibitors into adhesive systems have shown to be promising strategies to improve the longevity of adhesive restorations. The aim of this study was to evaluate the long-term bonding performance and anti-gelatinolytic effect of a 10-MDP-based universal adhesive system applied in combination with 2% chlorhexidine digluconate (CHX). For that, this study assessed the resin-dentin bond strength and the in situ gelatinolytic activity profile at the adhesive interface at initial and after 6 month of storage. One hundred and two sound human third molars were prepared and randomly divided into 3 groups according to the adhesive strategy: SB (two-step etch-and-rinse adhesive, Adper Single Bond 2, 10-MDP-free control group); SU-ER (Adper Single Bond Universal, 10-MDP containing universal adhesive applied on etch-and-rinse mode); and SU-SE (SU applied on self-etching mode). The groups were subdivided into two according to the dentin pretreatment: W - water or CHX- 2% chlorhexidine digluconate aqueous solution (SB-W; SB-CHX; SU-ER-W; SU-ER-CHX; SU-SE-W; SU-SE-CHX) and subsequently restored according to the manufacturer's instructions. Bond strength (n = 12) was assessed by a microtensile test (µTBS) (500N/0.5 mm/min) after 24h or after 6 months of storage. In situ zymography was performed to evaluate anti-gelatinolytic activity (n = 5). Resin-dentin samples were incubated with fluorescein-conjugated gelatin for 24 h at 37 °C and analyzed by confocal laser scanning microscopy. Fluorescence indicating gelatinolytic activity at hybrid layer zone and adjacencies was quantified using Image J. Data was analyzed by three-way ANOVA and Tukey post-hoc tests (p < 0.05). Results: SU-SE showed the highest bond strength values, while similar results were observed for SU-ER and SB. No statistical significant differences were observed between pretreatment (CHX vs. W) or storage time (initial vs. 6 months of aging). For in situ zymography, fluorescence was detected in all groups and CHX pre-treatment was able to inhibit the gelatinolytic activity in all conditions. The 10-MDP-based universal adhesive system in self-etching mode was the strategy that showed the best bonding performance irrespective of its combination with chlorhexidine. Pre-treatment with CHX did not impair the bond strength when used in combination with 10-MDP and it may promote collagen stability overtime.

Neurosensory analysis of tooth sensitivity during at-home dental bleaching: a randomized clinical trial.

Objective The objective of this study was to evaluate dental sensitivity using visual analogue scale, a Computerized Visual Analogue Scale (CoVAS) and a neurosensory analyzer (TSA II) during at-home bleaching with 10% carbamide peroxide, with and without potassium oxalate. Materials and Methods Power Bleaching 10% containing potassium oxalate was used on one maxillary hemi-arch of the 25 volunteers, and Opalescence 10% was used on the opposite hemi-arch. Bleaching agents were used daily for 3 weeks. Analysis was performed before treatment, 24 hours later, 7, 14, and 21 days after the start of the treatment, and 7 days after its conclusion. The spontaneous tooth sensitivity was evaluated using the visual analogue scale and the sensitivity caused by a continuous 0°C stimulus was analyzed using CoVAS. The cold sensation threshold was also analyzed using the TSA II. The temperatures obtained were statistically analyzed using ANOVA and Tukey's test (α=5%). Results The data obtained with the other methods were also analyzed. 24 hours, 7 and 14 days before the beginning of the treatment, over 20% of the teeth presented spontaneous sensitivity, the normal condition was restored after the end of the treatment. Regarding the cold sensation temperatures, both products sensitized the teeth (p<0.05) and no differences were detected between the products in each period (p>0.05). In addition, when they were compared using CoVAS, Power Bleaching caused the highest levels of sensitivity in all study periods, with the exception of the 14th day of treatment. Conclusion We concluded that the bleaching treatment sensitized the teeth and the product with potassium oxalate was not able to modulate tooth sensitivity.

Sodium Trimetaphosphate as a Novel Strategy for Matrix Metalloproteinase Inhibition and Dentin Remineralization.

The effect of sodium trimetaphosphate (STMP) as an antiproteolytic and remineralizing agent on demineralized dentin was evaluated in vitro. The inhibitory potential of STMP at 0.5, 1.5, 3.5, and 5% against recombinant matrix metalloproteinases (MMPs) MMPs-2 and -9 was assessed by zymography. To investigate its remineralization potential, 40 bovine root specimens were obtained and subjected to a demineralization protocol to produce caries-like dentin lesions. After that, dentin surfaces were divided into 3 areas: (1) mineralized (no treatment); (2) demineralized; and (3) demineralized/treated with STMP and submitted to a pH-cycling associated or not with STMP (1.5, 3.5, or 5% STMP, 10 min of treatment). After that, superficial hardness (SH) and cross-sectional hardness (CSH) were determined. Polarized light microscopy (PLM) was used to qualitatively evaluate mineralization within the caries-like lesions. The zymographic analysis showed that STMP solution is a potent inhibitor of the gelatinolytic activity of MMPs-2 and -9 depending on the dose, since the lowest concentration (0.5%) partially inhibited the enzyme activity, while the higher concentrations completely inhibited enzyme activity. Regarding remineralization effect, only 1.5% STMP solution enhanced both the SH and CSH. PLM showed that the area treated with 1.5% STMP presented similar birefringence as mineralized sound dentin. In conclusion, 1.5% STMP solution is effective as an antiproteolytic agent against MMPs and promotes dentin remineralization.

Use of sodium trimetaphosphate in the inhibition of dentin matrix metalloproteinases and as a remineralizing agent.

OBJECTIVES: Because of its ability to act as an antiproteolytic agent, the effect of sodium trimetaphosphate (STMP) against specific enzymes extracted from sound dentin and its performance under acidic challenge on demineralized dentin were investigated. METHODS: The antiproteolytic potential of STMP (0.5%, 1.0%, and 1.5%) was assessed in triplicate by zymography. For the evaluation of remineralization activity, 50 bovine-root dentin specimens were selected and randomly divided into 5 groups (n=10). Three areas were determined for each specimen: 1) control (no treatment); 2) demineralized (artificial caries-like challenge); 3) treated (demineralized and subjected to pH-cycling for 7days, and treated for 10min with 1.5% STMP, 1.5% STMP+calcium hydroxide (Ca[OH]2), 1.5% STMP+sodium fluoride (NaF), NaF, or deionized H2O). The dentin specimens were analyzed for superficial hardness (SH) and cross-sectional hardness (CSH) at different depths (10, 30, 50, 70, 90, 110, and 220µm) using a Knoop penetrator (10g/10s). Statistical analyses were performed with analysis of variance (ANOVA) and Tukey tests (p<0.05). RESULTS: The zymographic analysis showed that 1.5% STMP promoted complete inhibition of gelatinolytic activity. Therefore, 1.5% STMP was investigated in association with supplemented calcium or fluoride; a combination of 1.5% STMP and Ca(OH)2 significantly increased the mechanical properties of the treated dentin. CONCLUSION: 1.5% STMP serves as an antiproteolytic agent against matrix metalloproteinases extracted from human dentin. Furthermore, when supplemented with Ca(OH)2, 1.5% STMP may potentially induce remineralization. CLINICAL SIGNIFICANCE: STMP can be introduced as a novel strategy that combines enzymatic inhibition and remineralizing potential, which can serve to strengthen dentin and improve stability. STMP may have potential in the treatment of demineralized dentin lesions, especially when supplemented with calcium.

Neurosensory analysis of tooth sensitivity during at-home dental bleaching: a randomized clinical trial

Abstract Objective The objective of this study was to evaluate dental sensitivity using visual analogue scale, a Computerized Visual Analogue Scale (CoVAS) and a neurosensory analyzer (TSA II) during at-home bleaching with 10% carbamide peroxide, with and without potassium oxalate. Materials and Methods Power Bleaching 10% containing potassium oxalate was used on one maxillary hemi-arch of the 25 volunteers, and Opalescence 10% was used on the opposite hemi-arch. Bleaching agents were used daily for 3 weeks. Analysis was performed before treatment, 24 hours later, 7, 14, and 21 days after the start of the treatment, and 7 days after its conclusion. The spontaneous tooth sensitivity was evaluated using the visual analogue scale and the sensitivity caused by a continuous 0°C stimulus was analyzed using CoVAS. The cold sensation threshold was also analyzed using the TSA II. The temperatures obtained were statistically analyzed using ANOVA and Tukey's test (α=5%). Results The data obtained with the other methods were also analyzed. 24 hours, 7 and 14 days before the beginning of the treatment, over 20% of the teeth presented spontaneous sensitivity, the normal condition was restored after the end of the treatment. Regarding the cold sensation temperatures, both products sensitized the teeth (p<0.05) and no differences were detected between the products in each period (p>0.05). In addition, when they were compared using CoVAS, Power Bleaching caused the highest levels of sensitivity in all study periods, with the exception of the 14th day of treatment. Conclusion We concluded that the bleaching treatment sensitized the teeth and the product with potassium oxalate was not able to modulate tooth sensitivity.

The use of sodium trimetaphosphate for matrix metalloproteinase inhibition, remineralization and bonding to dentin / O uso de trimetafosfato de sódio sobre a inibição de metaloproteinases e na remineralização e adesão à dentina

The adhesive process to dentin substrate depends on the condition determined by the combined action of the mineral loss and the endogenous enzymes activity. Thus, considering a more complete therapeutic approach, sodium trimetaphosphate (STMP) may be a novel strategy that conciliates the remineralization potential to the promotion of dentin strengthening and its stability, possibly directing mineral nucleation and controlling the rate of biodegradation. In this study, the effect of STMP was evaluated in 2 studies. In study 1, different concentrations of STMP (0.5, 1.5, 3.5 and 5%) were investigated to assess their anti-proteolytic capacity on human purified MMPs-2 and -9 by zymography. Afterwards, only the concentrations (1.5, 3.5 and 5%) that showed total inhibition of both MMPs were used to evaluate their remineralizing capacity in dentin substrate submitted to artificial cariogenic challenge, through surface hardness (SH) and cross-sectional hardness (CSH). In study 2, based on the previous results, the capacity of the 1.5% STMP associated or not with NaF or Ca(OH)2 solutions in improving the dentin bond strength of a universal adhesive system was evaluated by the microtensile test . Thus, these studies suggest that 1.5% STMP is an effective inhibitor of collagen degradation mediated by purified human MMPs-2 and -9. In addition, demineralized and treated dentin with 1.5% STMP supplemented with Ca(OH)2 may induce remineralization. Thus, the use of STMP can be introduced as a new strategy that combines enzymatic inhibition and remineralization potential, reestablishing favorable conditions to affected dentin. These evidences support perspectives of therapies to restructure dentin and propose feasible and promising clinical strategies.(AU)

O processo adesivo ao substrato dentinário depende da condição determinada pela ação combinada da perda mineral e atividade de enzimas endógenas. Deste modo, considerando uma abordagem terapêutica mais completa, o trimetafosfato de sódio (STMP) pode ser uma estratégia inovadora que concilia o potencial remineralizador à promoção do fortalecimento da dentina e sua estabilidade, possivelmente direcionando a nucleação mineral e controlando a taxa de biodegradação. Neste trabalho, o efeito do STMP foi avaliado em 2 estudos. No estudo 1, diferentes concentrações de STMP (0,5; 1,5; 3,5 e 5%) foram investigadas para avaliar sua capacidade anti-proteolítica sobre as MMPs-2 e -9 purificadas humanas, por zimografia. Posteriormente, somente as concentrações (1,5; 3,5 e 5%) que apresentaram capacidade de inibição total de ambas MMPs foram utilizadas para avaliar sua capacidade remineralizadora em substrato dentinário submetido ao desafio cariogênico artificial, através da dureza de superfície (DS) e longitudinal (DL). No estudo 2, baseado nos resultados anteriores, foi avaliada a capacidade do STMP à 1,5% associado ou não a soluções de NaF ou Ca(OH)2 em melhorar a resistência de união à dentina de um sistema adesivo universal pelo teste de microtração. Desta forma, estes estudos sugerem que o STMP à 1,5% apresenta-se como um inibidor eficaz da degradação do colágeno mediada por MMPs-2 e -9 humanas purificadas. Além disso, a dentina humana desmineralizada e tratada com STMP à 1,5% suplementada com Ca(OH)2 pode induzir à remineralização. Assim, o uso de STMP pode ser introduzido como uma nova estratégia que combina inibição enzimática e potencial de remineralização, reestabelecendo condições favoráveis a partir de uma dentina afetada. Estas evidências sustentam perspectivas de terapias para reestruturar a dentina e propor estratégias clínicas factíveis e promissoras.(AU)

Influence of composite resins volume and C-factor on theshrinkage polymerization stress / Influência do volume das resinas compostas e do fator-C na tensão da contração de polimerização

Composite polymerization contraction isan inherent process of chemical and light composite resin activation. Consequently, this fact has been associated to potential clinical problems. The aim of the present in vitro study was to evaluate the volumeand C-factor influence on chemical and light-curing composite resin polymerization shrinkage stress, using a non-rigid method that there by provide slower stress values, causing a minimal deflection inload cell. Material and Method: The contractionforces of the Z-250 and Concise composite resins during polymerization were recorded in an UTMin two experiments. In the first experiment, the composite Z-250 was inserted in a single increment, polymerized for 20s and the forces generated were recorded for 120s. In the second experiment, a pairof rectangular steel plates (3x2mm) and two squaresteel plates (2x2mm), with varied heights (2; 3 mm,respectively), were used to determine the C-factor(0.6; 0.3) influence. Results: The polymerizedZ-250 results showed that the volume variations, independent of the C-factor, had a direct influenceon the shrinkage stress, different from the Concise, which was influenced by the C-factor. Conclusion: This study showed that a higher volume of composite resins determines an increase in the shrinkage stressof light-curing composites...

Contração de polimerização é um processo inerente das resinas compostas de ativação química e fotoativada. Consequentemente, esse fato tem sido associado a potenciais problemas clínicos. O objetivo do presente estudo in vitro foi avaliar a influência do volume e do fator-C na tensão da contração de polimerização em resinas química e fotoativada, utilizando um método não rígido que, dessa forma, fornece valores baixos de tensão, causando mínima deflexão na célula de carga. Material e Métodos: As forças de contração das resinas compostas Z-250 e Concise durante a polimerização foram registradas em uma UTM, dividida em dois experimentos. No primeiro experimento, a resina Z-250 foi inserida em um único incremento, polimerizada por 20 s e as tensões geradas foram registradas durante 120 s. No segundo estudo, um par de placas retangulares de aço (3x2 mm) e duas placas de aço quadradas (2x2mm), variando a altura (2 e 3 mm, respectivamente),foram usadas para determinar a influência do fator-C(0,6 e 0,3). Resultados: Os resultados da resina fotopolimerizável Z-250 mostraram que as variações do volume, independente do fator-C teve uma influência direta sobre a tensão de polimerização,diferente da Concise, a qual foi influenciada pelo fator-C. Conclusão: Esse estudo mostrou que um volume maior de resina composta determina um aumento na tensão de contração de polimerização...

Effect of thermocycling to adhesive interface of enamel analyzed by polarized light microscopy / Análise do efeito da termociclagem na interface adesivo do esmalte analisada por microscopia de luz polarizada

Objetivo: A desmineralização menos agressiva do esmalte por sistemas adesivos autocondicionantes resulta em maior descoloração, infiltração marginal e falhas em suas restaurações. Deste modo, este estudo teve como objetivo avaliar a microinfiltração por meio da técnica da infiltração de nitrato de prata e formação de tags na interface esmalte/adesivo. Material e Método: Duzentos fragmentos de esmalte foram divididos aleatoriamente em 10 grupos (n = 10) de acordo com o sistema adesivo (Single Bond Adper Plus- (SB), Clearfil Tri-S Bond- (CF), ou Scotchbond Universal- (SBU)) e a superfície do esmalte (lixada (GE), não lixada- (UE), condicionada com ácido fosfórico 37%- (PHA), ou sem condicionamento): (SB-UE), (SB-GE), (CF-UE), (CFGE), (CF-ue/pha), (CF-ge/pha), (SBU-ue), (SBU-ge), (SBU-ue/pha) e (SBU-ge/pha). Metade das amostras restauradas foram submetidas a 20.000 ciclos térmicos. Quatro fatias de 1,0 mm/amostra foram obtidas para avaliar a formação de tags e infiltração de nitrato de prata. Todas as amostras foram examinadas com microscopia de luz polarizada e a percentagem de infiltração foi quantificada. Resultados: Não foram observadas interações entre os três fatores. O sistema adesivo e envelhecimento exibiram uma interação. Foram encontradas diferenças significativas somente após termociclagem: os grupos SB e SBU condicionados apresentaram menor porcentagem de infiltração comparados aos outros grupos, independente do tipo de esmalte. Quanto à analise qualitativa, o comprimento dos tags após condicionamento ácido foi maior para o GE comparado ao UE, independente do sistema adesivo. Conclusão: A aplicação dos sistemas adesivos na técnica autocondicionante mostrou uma formação de tags significativamente menor comparada à técnica convencional. O condicionamento ácido do esmalte previamente aos sistemas adesivos multi-mode é fundamental para reduzir o grau de infiltração na interface adesiva após envelhecimento.

Objective: The less aggressive demineralization of enamel by self-etching systems results in greater staining, marginal leakage, and failure in their restorations, so this study aimed to assess the silver nitrate infiltration and tag formation of the enamel/adhesive interface. Material and Methods: Two hundred enamel fragments were randomly assigned into 10 groups according to the adhesive system (Single Bond Adper Plus- (SB), Clearfil Tri-S Bond-(CF), or Scotchbond Universal-(SBU)) and enamel surface (ground- (ge), unground-(ue), phosphoric acid etching- (pha), or none) (n=10): (SB-ue), (SB-ge), (CF-ue), (CF-ge), (CF-ue/pha), (CF-ge/pha), (SBU-ue), (SBU-ge), (SBU-ue/pha), and (SBUge/pha). Half of the restored samples were submitted to thermocycling. Four slices of 1.0mm/ sample were obtained to evaluate tag formation and silver nitrate infiltration. All of the specimens were examined with Polarized Light Microscopy, and the percentage of infiltration was quantified. Results: No interactions were found among the three factors. The adhesive and aging exhibited an interaction. Significant differences were found only after thermocycling: the SB and SBU-etched groups had decreased infiltration compared with the other groups. The tag length after etching was higher for ge compared with ue, regardless of the adhesive system. Conclusion: The selfetching techniques resulted in significantly less tag formation compared with the conventional technique. The acid pre-etching of enamel with the multi-mode adhesive was fundamental for reducing the degree of infiltration of the adhesive interface after aging

Effectiveness of plant-derived proanthocyanidins on demineralization on enamel and dentin under artificial cariogenic challenge.

UNLABELLED: Dental caries is considered a disease of high prevalence and a constant problem in public health. Proanthocyanidins (PAs) are substances that have been the target of recent studies aiming to control or treat caries. OBJECTIVE: The aim of this in vitro study was to evaluate the efficacy of a treatment with grape seed extract, under cariogenic challenge, to minimize or even prevent the onset of caries in the enamel and dentin. MATERIAL AND METHODS: Blocks of enamel and dentin (6.0x6.0 mm) were obtained from bovine central incisors, polished, and selected by analysis of surface microhardness (SH). The blocks were randomly divided into 3 groups (n=15), according to the following treatments: GC (control), GSE (grape seed extract), GF (fluoride - 1,000 ppm). The blocks were subjected to 6 daily pH cycles for 8 days. Within the daily cycling, the specimens were stored in buffered solution. The blocks were then analyzed for perpendicular and surface hardness and polarized light microscopy. RESULTS: The means were subjected to statistical analysis using the ANOVA and Fisher's PLSD tests (p<0.05). For enamel SH, GF showed the highest hardness values. In the dentin, GF was also the one that showed higher hardness values, followed by GSE. Regarding the cross-sectional hardness values, all groups behaved similarly in both the enamel and dentin. The samples that were treated with GSE and fluoride (GF) showed statistically higher values than the control. CONCLUSION: Based on the data obtained in this in vitro study, it is suggested that grape seed extract inhibits demineralization of artificial carious lesions in both the enamel and dentin, but in a different scale in each structure and in a smaller scale when compared to fluoride.

Effectiveness of plant-derived proanthocyanidins on demineralization on enamel and dentin under artificial cariogenic challenge

Dental caries is considered a disease of high prevalence and a constant problem in public health. Proanthocyanidins (PAs) are substances that have been the target of recent studies aiming to control or treat caries. Objective The aim of this in vitro study was to evaluate the efficacy of a treatment with grape seed extract, under cariogenic challenge, to minimize or even prevent the onset of caries in the enamel and dentin. Material and Methods Blocks of enamel and dentin (6.0x6.0 mm) were obtained from bovine central incisors, polished, and selected by analysis of surface microhardness (SH). The blocks were randomly divided into 3 groups (n=15), according to the following treatments: GC (control), GSE (grape seed extract), GF (fluoride – 1,000 ppm). The blocks were subjected to 6 daily pH cycles for 8 days. Within the daily cycling, the specimens were stored in buffered solution. The blocks were then analyzed for perpendicular and surface hardness and polarized light microscopy. Results The means were subjected to statistical analysis using the ANOVA and Fisher's PLSD tests (p<0.05). For enamel SH, GF showed the highest hardness values. In the dentin, GF was also the one that showed higher hardness values, followed by GSE. Regarding the cross-sectional hardness values, all groups behaved similarly in both the enamel and dentin. The samples that were treated with GSE and fluoride (GF) showed statistically higher values than the control. Conclusion Based on the data obtained in this in vitro study, it is suggested that grape seed extract inhibits demineralization of artificial carious lesions in both the enamel and dentin, but in a different scale in each structure and in a smaller scale when compared to fluoride. .

Demineralization and hydrogen peroxide penetration in teeth with incipient lesions.

The aim of this study was to evaluate the demineralization and hydrogen peroxide (HP) penetration in teeth with incipient lesions submitted to bleaching treatment. For analysis of HP penetration, sound and demineralized enamel/dentin discs were placed in artificial pulp chambers containing acetate buffer solution. After bleaching treatment, this solution was subjected for analysis of optical density by spectrophotometry and the disc surfaces were analyzed with scanning electron microscopy (SEM) and polarized light microscopy (PLM). The remaining discs were subjected for cross-sectional hardness analysis at different depths. Data were analyzed by repeated measures ANOVA and PLSD Fisher test (a=0.05). It was observed that previously demineralized teeth showed greater HP penetration (p<0.05). The bleaching treatment caused changes to a depth of 20 µm in sound enamel and up to 90 µm in demineralized enamel. SEM and PLM images revealed that the bleaching treatment caused superficial changes that were considerably more accentuated in previously demineralized teeth. It may be concluded that the enamel mineralization level influences HP penetration and the bleaching agent contributed to increase the demineralization depth.

Demineralization and Hydrogen Peroxide Penetration in Teeth with Incipient Lesions

The aim of this study was to evaluate the demineralization and hydrogen peroxide (HP) penetration in teeth with incipient lesions submitted to bleaching treatment. For analysis of HP penetration, sound and demineralized enamel/dentin discs were placed in artificial pulp chambers containing acetate buffer solution. After bleaching treatment, this solution was subjected for analysis of optical density by spectrophotometry and the disc surfaces were analyzed with scanning electron microscopy (SEM) and polarized light microscopy (PLM). The remaining discs were subjected for cross-sectional hardness analysis at different depths. Data were analyzed by repeated measures ANOVA and PLSD Fisher test (a=0.05). It was observed that previously demineralized teeth showed greater HP penetration (p<0.05). The bleaching treatment caused changes to a depth of 20 µm in sound enamel and up to 90 µm in demineralized enamel. SEM and PLM images revealed that the bleaching treatment caused superficial changes that were considerably more accentuated in previously demineralized teeth. It may be concluded that the enamel mineralization level influences HP penetration and the bleaching agent contributed to increase the demineralization depth.

O objetivo deste estudo foi avaliar a desmineralização e a penetração do peróxido de hidrogênio (HP) em dentes com lesões incipientes submetidos ao tratamento clareador. Para analisar a penetração do peróxido de hidrogênio, discos de esmalte/dentina hígidos e desmineralizados foram posicionados em câmaras pulpares artificiais contendo solução tampão de acetato. Após o tratamento clareador, esta solução foi submetida à análise da densidade óptica no espectrofotômetro e as superfícies dos discos foram analisadas por meio de microscopia eletrônica de varredura (MEV) e microscopia de luz polarizada (MLP). Os discos restantes foram submetidos à análise de microdureza transversal em diferentes profundidades. Os dados foram submetidos aos testes ANOVA e teste PLSD Fisher (= 5%). Observou-se que os dentes previamente desmineralizados mostraram maior penetração de HP (p<0,05). O tratamento clareador causou alterações em uma profundidade de 20 μm em esmalte hígido e até 90 μm em esmalte desmineralizado. As imagens obtidas em PLM e MEV mostraram que o tratamento clareador promove alterações superficiais no esmalte, sendo mais pronunciadas em dentes previamente desmineralizados. Foi concluído que o nível de mineralização do esmalte influencia a penetração do PH e que o agente clareador contribuiu para o aumento da profundidade de desmineralização.

Transenamel and Transdentinal Penetration of H2O2 in Restored Bovine Teeth.

PURPOSE: To quantify hydrogen peroxide (H2O2) penetration into restored bovine teeth subjected to whitening treatment. MATERIALS AND METHODS: Seventy-five enamel/dentin disks were divided into 5 groups (n = 15): intact disks (G1); cavity preparation only (G2); conventional adhesive system and composite resin (G3); resin-modified glass-ionomer cement (G4); and self-etching adhesive only (G5). After 24 h, the disks were placed into artificial pulp chambers containing an acetate buffer solution, and the first whitening session was performed using a 35% H2O2 (hydrogen peroxide) product. The disks were submitted to 10,000 thermal cycles and then stored for 1 year in deionized water. After this period, a second whitening session was performed. After each whitening procedure, the buffer solutions were analyzed for optical density in a spectrophotometer to assess the amount of H2O2 that had diffused. ANOVA and Tukey's test were used to compare the different groups and a Student's t-test was used to compare the different times (p ≤ 0.05). RESULTS: Prior to aging, group 2 had the highest penetration of H2O2; the other groups showed similar, lower penetration. After thermocycling and aging, all groups showed a significant increase in H2O2 penetration. The greatest penetration of H2O2 into the pulp chamber was found in groups 2 and 5. CONCLUSION: Aged restorations allowed greater H2O2 permeation through the tooth structure.

Replacement of fractured amalgam restoration in shallow cavities using a new category of adhesive system: case report / Substituição de restaurações de amálgama rasas e fraturadas utilizando uma nova categoria de sistema adesivo: relato de casos clínicos

Diversas são as falhas relacionadas às restaurações de amálgama, sendo necessário o reparo ou a substituição. Objetivo: O objetivo deste relato de casos clínicos foi apresentar uma condição comumente encontrada no consultório odontológico: restaurações de amálgama rasas fraturadas aliadas ao desejo do paciente de restaurações estéticas. Caso clínico: Foram realizadas em duas pacientes sete trocas de restaurações de amálgama fraturadas, provavelmente devido à profundidade inadequada dos preparos cavitários. As substituições foram executadas por 3 operadores diferentes, utilizando-se um sistema autocondicionante “multi-mode” com a técnica de condicionamento seletivo do esmalte e uma resina composta nanoparticulada com boas propriedades mecânicas e polimento. Ao final, pode-se verificar resultados estéticos satisfatórios para todas as restaurações, porém com variação entre os operadores, salientando a importância do treinamento do profissional, assim como atender o desejo estético do paciente. Conclusão: Dessa forma, pode-se concluir que a forma de resistência e retenção dos preparos para amálgama foi a principal causa das falhas das restaurações neste estudo. Além do mais, na presença de restaurações de amálgama com falhas, estas devem ser reparadas ou substituídas criteriosamente para evitar prejuízo ao remanescente dental; sendo a resina composta o material de eleição para substituição, por ser mais conservador e estético.

Several failures have been related in amalgam restorations that require repair or replacement. Objective: The aim of this case report was to demonstrate a usual clinical condition found in the dental office: fractured in amalgam restorations associated with the esthetic patient desire. Case report: Seven fractured amalgam restoration replacements, probably due to improper cavity design, were performed in two patients. Three different operators accomplished the replacements. It was applied a “multi-mode” adhesive system using the selective enamel etching technique and a nanofilled resin composite with good mechanical proprieties and polishing. At the end, satisfactory esthetic results were achieved for all restorations. However, differences among operators were detected, stressing the importance of professional training and esthetic desire. Conclusion: Thus, it was concluded that the resistance and retention form of amalgam design was the major concern on the failed amalgam restorations in this study. In addition, amalgam restorations must be replaced carefully to prevent damage the dental remaining, and the resin composite has been selected as a preferred option for amalgam replacement, since it is more conservative and esthetic.

Efeito de diferentes fontes luminosas e pré-condicionamento do esmalte na alteração de cor, penetração de H2O2 e citotoxicidade em dentes clareados / Effect of different light sources and pre-conditioning of enamel in color change, H2O2 penetration and cytotoxicity in bleached teeth

Este estudo avaliou o efeito do condicionamento ácido do esmalte dental e do uso de diferentes fontes luminosas (luz halógena, LED e, LED/LASER) com um produto clareador na alteração de cor, penetração do peróxido de hidrogênio e citotoxicidade ao longo do tempo. A alteração de cor (ΔE) e a quantificação do peróxido permeado foram realizadas em espectrofotômetro. O metabolismo celular foi avaliado pelo teste do MTT e a morfologia por MEV. Os resultados mostraram uma alteração progressiva nos valores de ΔE em todos os tratamentos realizados, no entanto, não houve diferença nos valores de ΔE e na permeação de peróxido de hidrogênio entre as condições experimentais. Verificou-se no teste MTT que o clareamento dentário produziu uma redução significativa no metabolismo celular, independentemente do uso ou não das fontes luminosas. O pré-condicionamento do esmalte dentário não influenciou no metabolismo celular em nenhum grupo. Conclui-se que a associação do produto clareador com diferentes fontes luminosas e/ou com o pré-condicionamento ácido do esmalte são poucos significativos na alteração de cor, penetração trans-amelodentinária de peróxido de hidrogênio, citotoxicidade e morfologia celular...

This study evaluated the effect of acid etching of the enamel and the combination of different light sources (halogen light, LED and LED/LASER) with bleaching product on the color change, penetration of hydrogen peroxide and cytotoxicity during the time. The color change (ΔE) and the measurement of peroxide that permeated the tooth tissue were analyzed by spectrophotometer. Cell metabolism was evaluated by MTT assay and the morphology by SEM. The results showed no difference in the values of ΔE and in the permeation of hydrogen peroxide in all experimental conditions. It was found that tooth whitening produced a significant reduction in cell metabolism, regardless of the use or not the light source. The preconditioning of the enamel did not influence the cellular metabolism in either group. It was concluded that the association of the bleaching product with different light sources and/or the preconditioning of the enamel are few significant in color change, trans-enamel and trans-dentinal penetration of hydrogen peroxide, cytotoxicity and cell morphology...

Efeito de diferentes fontes luminosas e pré-condicionamento do esmalte na alteração de cor, penetração de H2O2 e citotoxicidade em dentes clareados / Effect of different light sources and pre-conditioning of enamel in color change, H2O2 penetration and cytotoxicity in bleached teeth

Este estudo avaliou o efeito do condicionamento ácido do esmalte dental e do uso de diferentes fontes luminosas (luz halógena, LED e, LED/LASER) com um produto clareador na alteração de cor, penetração do peróxido de hidrogênio e citotoxicidade ao longo do tempo. A alteração de cor (ΔE) e a quantificação do peróxido permeado foram realizadas em espectrofotômetro. O metabolismo celular foi avaliado pelo teste do MTT e a morfologia por MEV. Os resultados mostraram uma alteração progressiva nos valores de ΔE em todos os tratamentos realizados, no entanto, não houve diferença nos valores de ΔE e na permeação de peróxido de hidrogênio entre as condições experimentais. Verificou-se no teste MTT que o clareamento dentário produziu uma redução significativa no metabolismo celular, independentemente do uso ou não das fontes luminosas. O pré-condicionamento do esmalte dentário não influenciou no metabolismo celular em nenhum grupo. Conclui-se que a associação do produto clareador com diferentes fontes luminosas e/ou com o pré-condicionamento ácido do esmalte são poucos significativos na alteração de cor, penetração trans-amelodentinária de peróxido de hidrogênio, citotoxicidade e morfologia celular

This study evaluated the effect of acid etching of the enamel and the combination of different light sources (halogen light, LED and LED/LASER) with bleaching product on the color change, penetration of hydrogen peroxide and cytotoxicity during the time. The color change (ΔE) and the measurement of peroxide that permeated the tooth tissue were analyzed by spectrophotometer. Cell metabolism was evaluated by MTT assay and the morphology by SEM. The results showed no difference in the values of ΔE and in the permeation of hydrogen peroxide in all experimental conditions. It was found that tooth whitening produced a significant reduction in cell metabolism, regardless of the use or not the light source. The preconditioning of the enamel did not influence the cellular metabolism in either group. It was concluded that the association of the bleaching product with different light sources and/or the preconditioning of the enamel are few significant in color change, trans-enamel and trans-dentinal penetration of hydrogen peroxide, cytotoxicity and cell morphology