Minimal intervention in dentistry: which is the best approach for silorane composite restoration repairs?

BACKGROUND: This study aimed to evaluate surface treatments, adhesives and composites for repairing silorane based restorations. MATERIAL AND METHODS: One hundred and twenty truncated cones (2 mm smaller diameter and 4 mm larger diameter) made of silorane composite were divided in 12 groups according with the surface treatment (diamond bur and oxide aluminum abrasion), the adhesive (Adper Scothbond Multipurpose (3M ESPE), Ecusit (Voco) and Filtek P90 Adhesive (3M ESPE)). Each group was subdivided in two according with the composite used for repair (methacrylate and silorane). The repair was made with a second truncated cone build over the first one and bond strength assssed by tensile strength. Data were submitted to ANOVA 3-way and Tukey's test (p<0.05). RESULTS: There was difference only for the adhesives and the composites, with conventional adhesives (Adper Scothbond Mutipurpose) and methacrylate-based composites (Filtek Z350) presenting superior tensile strength compared to the silorane ones (P90 Adhesive system and composite). CONCLUSIONS: Therefore, it must be concluded that silorane composite can be repaired with methacrylate base composites and adhesives. Key words:Silorane composites, composites, bond strength, minimal intervention.

Avaliação das propriedades de um sistema adesivo modificado por um antibacteriano peptídico / Evaluation of the properties of an adhesive system modified by a peptidic antibacterial

O objetivo desse estudo foi avaliar as propriedades de um sistema adesivo modificado com a incorporação de um antibacteriano peptídico, Nisina pura (Handary, Belgium), a qual é amplamente utilizada para conservação de alimentos, em duas diferentes concentrações, 0,5% e 1,0%. Foram avaliados a resistência de união da interface adesiva, o grau de conversão e a atividade antibacteriana, além da análise por meio do Estereomicroscópio e Microscópio Eletrônico de Varredura (MEV). Os adesivos foram divididos em três grupos de acordo com a concentração de nisina (Handary, Belgium) incorporada ao sistema adesivo em cada grupo (n=10): SB ­ Adesivo Comercial Single Bond 2 (3M-ESPE), SBN05 ­ Single Bond 2 + Nisina 0,5%, SBN1 - Single Bond 2 + Nisina 1%. Para o teste de resistência de união foram utilizados 30 molares humanos hígidos (n=10). O grau de conversão foi feito por infravermelho por transformada de Fourier (FTIR), onde foram feitas três leituras das gotas do adesivo dos diferentes grupos. A atividade antibacteriana foi feita através dos testes de difusão em ágar e contagem da unidade formadora de colônia (UFC), realizado em triplicata, onde foram utilizados discos de adesivos polimerizados dos diferentes grupos. Os dados foram analisados estatisticamente quanto à sua normalidade. Como estes apresentaram distribuição normal, realizou-se o teste de análise de variância (ANOVA) e o teste de Tukey de 5%. Os resultados obtidos na microtração (MPa±Dp) foram SB 40,69±2,42A, SBN05 39,20±2,21A e SBN1 31,36±2,47B. No grau de conversão obtivemos como resultado SB 83,50±3,42A, SBN05 80,22±3,68A e SBN1 78,44±0,95A. Na atividade antibacteriana em difusão de ágar não houve diferença na formação de áreas de inibição, entretanto na unidade formadora de colônia obtivemos como resultado SB 0,51±0,02A, SBN1 0,36±0,03B e SBN05 0,30±0,04B. Pode-se concluir que a incorporação da nisina não interferiu no grau de conversão e na resistência de união na porcentagem de 0,5%, não apresentou área de inibição em difusão em ágar e apresentou atividade antibacteriana no teste UFC, mostrando seu efeito antibacteriano.

The objective of this study was to evaluate the properties of a modified adhesive system with the incorporation of a peptidic antibacterial, pure Nisin (Handary, Belgium), which is widely used for food preservation, in two different concentrations, 0.5% and 1.0%. The bond strength of the adhesive interface, the degree of conversion and antibacterial activity were evaluated, in addition to analysis using the Stereomicroscope and Scanning Electron Microscope (SEM). The adhesives were divided into three groups according to the concentration of nisin (Handary, Belgium) incorporated into the adhesive system in each group (n=10): SB ­ Single Bond 2 Adhesive (3M-ESPE), SBN05 ­ Single Bond 2 + Nisin 0,5%, SBN1 - Single Bond 2 + Nisin 1%. For the microtensile bond strength test, 30 healthy human molars (n = 10) were used. The degree of conversion was made in the Fourier transform infrared (FTIR), three readings of the drops of the adhesive of the different groups were made. The antibacterial activity was performed through the agar diffusion tests and colony forming unit (CFU) counting, performed in triplicate, where polymerized adhesive discs from different groups were used. The data were analyzed statistically for normality. As these presented normal distributions, the analysis of variance test (ANOVA) and the Tukey test of 5% were performed. The results obtained in microtensile (MPa±Dp) were SB 40,69±2,42A, SBN05 39,20±2,21A, SBN1 31,36±2,47B. In the degree of conversion, we got as a result SB 83,50±3,42A, SBN05 80,22±3,68A and SBN1 78,44±0,95A. In the antibacterial activity there was no difference in the formation of areas of inhibition. However, in the colony forming unit we obtained as a result SB 0,51±0,02A, SBN1 0,36±0,03B e SBN05 0,30±0,04B. It was concluded that the incorporation of nisin did not influence the degree of conversion of the adhesive and in the bond strength in the percentage of 0.5%, presented antibacterial activity (CFU), showing its antibacterial effect.

Adhesive systems effect over bond strength of resin-infiltrated and de/remineralized enamel.

Background: The purpose of this study was to evaluate the effect of different bonding agents on bond-strength to demineralized enamel after remineralizing treatments and resin infiltration. Methods: Buccal enamel of 120 bovine incisors was polished and then were divided into five experimental groups: SE (sound enamel); DE (demineralized enamel); AS (demineralized enamel immersed in artificial saliva for eight weeks); NaF (demineralized enamel treated with 0.05% sodium fluoride solution (one minute) for eight weeks); Ic (demineralized enamel infiltrated with a low-viscosity resin (Icon-DGM). These groups were subdivided according to adhesive system used: self-etching adhesive Adper Easy One (3M/ESPE) and etch-and-rinse adhesive Single Bond (3M/ESPE). The composite resin blocks were fabricated using a Teflon matrix. A thermomechanical cycling machine was used to carry out the artificial aging of the specimens and thus were sectioned into sticks. The microtensile tests were performed using a universal testing machine at a cross-head speed of 1 mm/min. Data (in MPa) were subjected to two-way ANOVA and Tukey's tests (5%). Results: Significant differences were found for both factors tested and interactions (p<0.05). Tukey's test results of µTBS (mean ± SD) were: etch-and-rinse SE (28.79±3.93); DE (30.41±7.22); AS (29.03±3.33); NaF (29.81±4.06)a; Ic (29.47±5.5);  and self-etching SE (30.37±6.96); DE (14.62±4.47); AS (9.79±2.32); NaF (9.36±2.31); Ic (30.78±8.68).   Conclusions: Resin infiltration did not affect the bond strength of demineralized enamel for both adhesive systems tested. For etch-and-rinse adhesive, no differences were observed for the tested groups. For self-etching adhesive, only the resin-infiltrated group showed similar bond strength to sound enamel. Both etch-and-rinse and self-etching adhesive systems can be used in resin-infiltrated enamel, if a composite restoration needs to be further performed. In enamel that has undergone the de/remineralization process, the use of a total-etch adhesive might be preferable for the restorative procedure.

Influence of simulated pulpal pressure on the variation of intrapulpal temperature during adhesive system light-curing / Influência da pressão pulpar simulada na variação de temperatura intrapulpar durante a fotopolimerização do sistema adesivo

Objective: To evaluate the effects of simulated pulpal pressure (SPP) on the variation of intrapulpal temperature (T) during lightcuring of the adhesive system. Material and Methods: One hundred sound human molars were sectioned from the highest pulp horn to obtain a 2-mm of thickness dentin. The specimens were randomly divided into two groups: (n = 50), according to the presence or absence of SPP (15 cm H2 O). The specimens were sequentially treated as follows: 37% phosphoric acid (Scotchbond Universal; 3M/ESPE), adhesive system (Scotchbond Universal/3M ESPE) and light-curing (10 s). T was evaluated during adhesive lightcuring with a K-type thermometer put inside the pulp chamber. Data were analysed by using Mann-Whitney's test (at 5%). Results: According to Mann-Whitney's test, the absence group presented a T of 2 °C, whereas the presence group 1 °C. The mean values of T were 0.82 ± 0.56 °C for the presence group and 2.30±0.73 °C for the absence group. Conclusion: Simulated pulpal pressure significantly reduced the temperature rise in the pulp chamber during light-curing of the adhesive system, showing the importance of inserting this protocol of simulated pulpal pressure in the laboratory procedures.(AU)

Objetivos: Avaliar os efeitos da pressão pulpar simulada (PPS) na variação de temperatura (DT) durante a fotopolimerização do sistema adesivo. Material e Método: Cem molares humanos hígidos foram seccionados para obtenção de 2 mm de espessura de dentina, a partir do corno pulpar mais alto. As amostras foram divididas aleatoriamente em 2 grupos (n = 50): ausência e presença de PPS (15 cm de H2 O). As amostras foram tratadas seqüencialmente com: ácido fosfórico 37% (Scotchbond Universal; 3M/ESPE), sistema adesivo (Scotchbond Universal/3M ESPE), seguida da fotopolimerização (10 s). Na seqüência, um bloco de resina composta (Filtek Z350 XT; 3M/ESPE) foi confeccionado sobre a área preparada. Para a fotopolimerização, utilizou-se o fotopolimerizador LED Light Curing System - Demi Plus (Kerr Corporation, Middleton, WI, USA), com potência de 1200 mW/cm2 . A DT foi avaliada durante a fotopolimerização do adesivo por meio de um termômetro digital no interior da câmara pulpar. Os dados obtidos foram avaliados pelo MannWhitney test (5%). Resultados: Segundo Mann-Whitney test, o grupo ausência sofreu DT de 2 °C, enquanto o grupo presença variou 1 °C. Os valores de média da DT foram de 0.82±0.56 °C para o grupo presenca de PPS e 2.30 ± 0.73 °C para o grupo ausência de PPS. Conclusão: A pressão pulpar simulada reduziu significantemente a elevação de temperatura na câmara pulpar durante a fotopolimerização do sistema adesivo, demonstrando a importância de inserir esse protocolo de simulação de pressão pulpar nos procedimentos laboratoriais.(AU)