PURPOSE To evaluate the polishing effect on roughness and color change of pressed and layering ceramics after immersion in coffee solution. MATERIALS AND METHODS 88 ceramic discs (1.0 mm × 10.0 mm) were manufactured - 44 nano-fluorapatite layering ceramics (IPS e.max Ceram. Group C) and 44 pressed lithium disilicate ceramic discs (IPS e. max Press - Group P). Each group was divided into 4 subgroups according to surface treatments: (G) Glaze, (S) Shofu polishing system (Shofu Inc.), (E) Edenta AG polishing System, (KG) 30-µm diamond granulation tip. Surface roughness (Ra) and color change (ΔE) measurings after the surface treatments were performed, before and 12 days after the immersion in coffee solution. A samples' qualitative analysis was conducted with a scanning electron microscopy (SEM). Data were statistically-treated with one-way-ANOVA and Duncan's tests, apart from paired t-test and Pearson's correlation test (α=5%). RESULTS The decrescent order, both for surface roughness (Ra) and ΔE for both ceramics were: KG > E > S > G ( P <.05). With exception for PG and CG subgroups, which did not present statistical difference between them, all other pressed ceramics subgroups presented smaller Ra values and greater ΔE values than the layering ceramics subgroups ( P <.05). CONCLUSION Although mechanical polishing systems presented intermediate Ra values, their colors were considered clinically acceptable. There is a strong correlation between the surface roughness and the color change of tested ceramics.

The choice of the best finishing/polishing methods for composite resin restorations is critical to the choice of excellence results related to longer clinical longevity. The objective of the study was to evaluate the influence of finishing and polishing systems on the surface roughness of a Nanoparticulate and Bulk-fill resin. For the research, 40 sample disks were prepared for each composite: single-increment (BF) (Bulk Fill 3M), both 2 mm thick and 10 mm in diameter (FZ) (Filtek Z350, 3M). The specimens were randomly divided into 4 groups with 10 samples each, according to the different materials to which they were subjected to the finishing and polishing protocols: control [C]- diamond tip (FG 4137F, FAVA); [EN] polishing discs (Enhance, Dentsply); [SL] Abrasive discs (Sof-Lex Pop-on, 3M) and [PD] felt disc + Polishing paste (Diamond Excel, FGM). A surface roughness (Ra) was verified with a roughness meter in three different data volumes and calculated as arithmetic means. Data were statistically treated by one way ANOVA followed by test t and student t test. Regardless of the data tested, evidence of the systemic controlling against different systems for polishing control with control (p <0.05). PD presented statistically greater roughness to the EN and SL (p <0.001), these in turn obtained similar performance and presented the lowest values of roughness for both composites (p> 0.05). The different finishing / polishing methods influenced the surface roughness of both composites, observing for Sof-lex and Enhance lower Ra values.Keywords: Nanoparticles. Dental Polishing. Composite Resins.ResumoA escolha dos adequados métodos de acabamento/polimento para restaurações de resina composta é fundamental para obtenção de resultados de excelência, relacionados a maior longevidade clínica. O objetivo desse estudo foi avaliar a influência dos sistemas de acabamento e polimento na rugosidade de superfície das resinas nanoparticuladas convencional e bulk-fill. Para a pesquisa foram confeccionados 40 discos de amostra para cada compósito: Convencional [FZ] (Filtek Z350, 3M) e de incremento único [BF] (Filtek Bulk Fill, 3M), ambas com 2 mm de espessura e 10 mm de diâmetro. Foram divididos aleatoriamente em 4 grupos com 10 amostras cada, de acordo com os diferentes protocolos que receberam, sendo: controle (C) ponta diamantada (FG 4137F, FAVA); (EN) discos de silicone (Enhance, Dentsply); (SL) discos abrasivos (Sof-Lex Pop-on, 3M); (PD) Feltro + Pasta diamantada (Diamond Excel, FGM). A rugosidade de superfície (Ra) foi verificada com um rugosímetro em três leituras de diferentes direções e calculadas as médias aritméticas. Os dados foram tratados estatisticamente pelos testes ANOVA 1 fator seguido pelo teste t e t de student (p<0,05). Independente da resina testada, evidenciou-se diminuição da rugosidade pelos diferentes sistemas de polimento frente ao grupo controle (p<0,05). PD apresentou rugosidade estatisticamente maior à EN e SL (p<0,001), estes últimos que por sua vez obtiveram desempenho semelhante e apresentaram os menores valores de rugosidade para ambos os compósitos (p>0,05). Os diferentes métodos de acabamento/polimento influenciaram na rugosidade de superfície dos dois compósitos testados, observando para Sof-lex e Enhance menores valores de Ra. Palavras-chave: Nanopartículas. Polimento Dentário. Resinas Compostas.

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A new class of composite resins called single fill resins (Bulk-Fill) was proposed to simplify restorative procedures. They allow filling dental cavities in layers of approximately 4mm. This study aims to compare the compression strength of single fill composites with different polymerization times. Four Bulk-Fill composites were used Filtek Bulk-Fill, Filtek Bulk-Fill Flow, Tetric N-Ceram Bulk-Fill, and Tetric N-Flow Bulk-Fill, and also a conventional composite Filtek Z350 XT as a control group. One hundred cylinders were manufactured in a matrix with 4.7mm diameter and 4mm height for Bulk-Fill compounds, and 2mm height for the control group. Half of the specimens of each material was photopolymerized for 10 seconds and the other half for 20 seconds (n = 10). The samples were stored in distilled water for 48 hours at 37°C and subjected to compression testing in a universal test machine. Variance analysis was performed with t-test of multiple comparisons between groups and student t-test for the different polymerization times with significance index p=0.05. The results did not show statistically significant difference in relation to polymerization time. However, there was a statistically significant difference between the control and Filtek Bulk-Fill Flow groups, which presented higher strenght to compression than the Filltek Bulk-Fill, Tetric N-Ceram Bulk-Fill, and Tetric N-Flow Bulk-Fill groups. The type of resin can influence its resistance to fracture. The polymerization time did not have any influence in the materials strength.

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