Influence of Mechanical and Chemical Degradation in the Surface Roughness, Gloss, and Color of Microhybrid Composites.

AIM: The aim of this study was to investigate the association of different degradations on the roughness, gloss, and color changes of microhybrid composites. MATERIALS AND METHODS: Ten specimens were prepared for Charisma, Amelogen Plus, Point 4, and Opallis resins. Surfaces were polished and baseline measurements of roughness, gloss, and color were recorded. Specimens were then submitted to chemical and mechanical challenges, and the specimens were reevaluated. Roughness and gloss were analyzed by Kruskal -Wallis and Dunn's test (p < 0.05). Color change (ΔE) was analyzed by one-way analysis of variance and Tukey's tests (p < 0.05). The initial and final data were compared using the Wilcoxon test (p < 0.05). Spearman test checked the correlation between the roughness and gloss (p < 0.05). RESULTS: Regarding surface roughness and gloss, there was no difference between composites before challenges. However, all composites showed a significant increase of roughness after challenges, with highest values for Charisma. The gloss was influenced by challenges, evidencing the best gloss for Point 4. Charisma showed the highest value of color change. There was no correlation between surface roughness and gloss for the initial analysis, and after the challenges. CONCLUSION: Composites were influenced by association of challenges, and Charisma showed the highest changes for roughness, gloss, and color. CLINICAL SIGNIFICANCE: The type of composite resin influenced the properties of materials, which are surface roughness, gloss, and color change. The dentist should be aware of the performance of different brands, to choose the correct required composite resin for each type of patient or region to be restored.

Repairability of aged resin composites mediated by different restorative systems.

The aim of this study was to evaluate the shear bond strength of resin composite repairs with and without aging of the surface to be repaired, using different adhesive systems and resin composites. Ninety specimens were prepared: 10 for the Control Group (GC - without repair); 40 for Group I (GI - repairs after 7 days) and 40 for Group II (GII - repairs after 180 days). Groups I and II were divided into 4 subgroups of 10 specimens each, according to the adhesive system and composite resin used: A) Adper Scotch Bond Multipurpose + Filtek Z350 XT; B) Adper Single Bond Plus + Filtek Z350 XT; C) Adper Scotch Bond Multipurpose + Esthet-X; D) Adper Single Bond Plus + Esthet-X. The specimens were tested for shear strength in a universal testing machine. The results were analyzed by two-factor one-way ANOVA and Fisher's post hoc tests (alpha=0.05). The control group had better performance than the other groups. There was no significant difference when comparing different adhesive systems and composite resins. Repairs performed at 7 days were better than those performed at 180 days. The composite repairs decreased the mechanical strength of the restoration. Aging of the resin substrate may decrease repair bond strength over time, regardless of the type of adhesive systems and resin composites used.

Avaliar a resistência de união ao cisalhamento de reparos de resina composta com e sem envelhecimento da superfície a ser reparada, utilizando diferentes sistemas adesivos. Noventa corpos de prova foram confeccionados sendo: 10 para o Grupo Controle (GC - sem reparo); 40 para o Grupo I (GI - reparos após 7 dias) e 40 para o Grupo II (GII ­ reparos após 180 dias). Para os reparos, os grupos GI e GII foram subdivididos em 4 subgrupos com 10 corpos de prova, variando o sistema adesivo e a resina composta: A) Adper Scotch Bond Multipurpose+ Filtek Z350XT; B)Adper Single Bond Plus+ Filtek Z350XT; C)Adper Scotch Bond Multipurpose+ Esthet-X; D) Adper Single Bond Plus+ Esthet-X. Os corpos de prova foram submetidos a uma força de cisalhamento em uma máquina de ensaio universal (EMIC). Os resultados foram analisados pelo teste estatístico Anova dois fatores, seguido pelo teste de Fisher´s. Observou-se melhor comportamento do grupo controle sobre os demais grupos, além disso, os reparos realizados aos 7 dias foram superiores aos dos realizados em 180 dias. Não houve diferença significativaquando se comparou diferentes sistemas adesivos e resinas compostas. Os reparos de resina composta diminuem a resistência mecânica da restauração.O envelheci mento do substrato de resina pode diminuir a resistência ao reparo ao longo do tempo, independentemente do tipo de sistemas adesivos e resinas compostas utilizados.

Repairabilitiy of aged resin composites mediated by different restorative systems / Reparo de resinas compostas envelhecidas e mediadas por diferentes materiais restauradores

The aim of this study was to evaluate the shear bond strengthof resin composite repairs with and without aging of thesurface to be repaired, using different adhesive systems andresin composites. Ninety specimens were prepared: 10 for theControl Group (GC - without repair); 40 for Group I (GI -repairs after 7 days) and 40 for Group II (GII - repairs after180 days). Groups I and II were divided into 4 subgroups of10 specimens each, according to the adhesive system andcomposite resin used: A) Adper Scotch Bond Multipurpose +Filtek Z350 XT; B) Adper Single Bond Plus + Filtek Z350 XT;C) Adper Scotch Bond Multipurpose + Esthet-X; D) AdperSingle Bond Plus + Esthet-X. The specimens were tested forshear strength in a universal testing machine. The resultswere analyzed by two-factor one-way ANOVA and Fisher’spost hoc tests (alpha=0.05). The control group had betterperformance than the other groups. There was no significantdifference when comparing different adhesive systems andcomposite resins. Repairs performed at 7 days were betterthan those performed at 180 days. The composite repairsdecreased the mechanical strength of the restoration. Agingof the resin substrate may decrease repair bond strength overtime, regardless of the type of adhesive systems and resin composites used.

Avaliar a resistência de união ao cisalhamento de reparos deresina composta com e sem envelhecimento da superfície a serreparada, utilizando diferentes sistemas adesivos. Noventacorpos de prova foram confeccionados sendo: 10 para o GrupoControle (GC - sem reparo); 40 para o Grupo I (GI - reparosapós 7 dias) e 40 para o Grupo II (GII – reparos após 180 dias).Para os reparos, os grupos GI e GII foram subdivididos em 4subgrupos com 10 corpos de prova, variando o sistema adesivoe a resina composta: A) Adper Scotch Bond Multipurpose+Filtek Z350XT; B)Adper Single Bond Plus+ Filtek Z350XT;C)Adper Scotch Bond Multipurpose+ Esthet-X; D) AdperSingle Bond Plus+ Esthet-X. Os corpos de prova foramsubmetidos a uma força de cisalhamento em uma máquina deensaio universal (EMIC). Os resultados foram analisados peloteste estatístico Anova dois fatores, seguido pelo teste deFisher ́s. Observou-se melhor comportamento do grupocontrole sobre os demais grupos, além disso, os reparosrealizados aos 7 dias foram superiores aos dos realizados em180 dias. Não houve diferença significativaquando secomparou diferentes sistemas adesivos e resinas compostas.Os reparos de resina composta diminuem a resistênciamecânica da restauração.O envelheci mento do substrato deresina pode diminuir a resistência ao reparo ao longo dotempo, independentemente do tipo de sistemas adesivos eresinas compostas utilizados.

Evaluation "in situ" of tag formation in dental enamel submitted to microabrasion technique. Effect of two etching times.

The objective of this study was to analyze the formation of resin tags on enamel surfaces submitted or not to enamel microabrasion technique. Thirteen undergraduate dental students received removable acrylic palatal appliances on which four sections from intact premolars were fixed, measuring 4.0 mm x 4.0 mm. Two sections received the application of a microabrasive system and the remaining sections did not receive any surface treatment. The patients were instructed to wear the acrylic palatal appliances for 4 months during the day. After this time, the sections were etched with 37% phosphoric acid for 15 seconds (sections 1 and 2) and 60 seconds (sections 3 and 4), followed by adhesive system and composite resin applications. All the sections were prepared for light microscopy analysis to observe the degree of resin penetration (x400). The results were submitted to a three-way analysis of variance with a significance level of 5%. The difference between groups was verified by the Tukey test, at a significance level of 5%. The results showed that microabraded enamel required a longer period of acid etching for longer resin tags.

Evaluation "in situ" of tag formation in dental enamel submitted to microabrasion technique: Effect of two etching times

The objective of this study was to analyze the formation of resin tags on enamel surfaces submitted or not to enamel microabrasion technique. Thirteen undergraduate dental students received removable acrylic palatal appliances on which four sections from intact premolars were fixed, measuring 4.0 mm X 4.0 mm. Two sections received the application of a microabrasive system and the remaining sections did not receive any surface treatment. The patients were instructed to wear the acrylic palatal appliances for 4 months during the day. After this time, the sections were etched with 37% phosphoric acid for 15 seconds (sections 1 and 2) and 60 seconds (sections 3 and 4), followed by adhesive system and composite resin applications. All the sections were prepared for light microscopy analysis to observe the degree of resin penetration (x400). The results were submitted to a three-way analysis of variance with a significance level of 5%. The difference between groups was verified by the Tukey test, at a significance level of 5%. The results showed that microabraded enamel required a longer period of acid etching for longer resin tags.

O objetivo deste estudo foi analisar a formacao de tags resinosos em esmalte dental submetido ou nao a tecnica de microabrasao. Treze estudantes de Odontologia receberam a aplicacao de um aparelho ortodontico removivel contendo quatro seccoes de esmalte com dimensoes de 4.0 mm X 4.0 mm. Duas secoes receberam a aplicacao de um composto microabrasivo e as demais nao receberam nenhum tratamento. Os pacientes foram instruidos a usar os aparelhos ortodonticos durante o dia e por quatro meses. Apos este periodo, as seccoes foram condicionadas com acido fosforico 37% por 15 segundos (secoes 1 e 2) e por 60 segundos (seccoes 3 e 4), seguido pela aplicacao do sistema adesivo e de resina composta. Todas as seccoes foram preparadas para analise em microscopia optica comum para observar o grau de penetracao do material resinoso (x400). Os resultados foram submetidos a analise de variancia a tres criterios, ao nivel de 5%. A diferenca entre os grupos foi verificada pelo teste de Tukey, ao nivel de 5%. Os resultados mostraram que maiores tempos de condicionamento acido do esmalte dental sao exigidos para uma maior penetracao do sistema adesivo.