"In vitro" performance of 2-step, total etch adhesives modified by thiourethane additives

Orientadores: Lourenço Correr Sobrinho, Carmem Silvia PfeiferTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Objetivo: avaliar as propriedades físicas e a resitência de união à microtração de adesivos experimentais contendo oligômeros de tiouretano (TU) e/ou partículas de carga funcionalizadas com TU. Materiais e métodos: uma matriz orgânica base contendo 60%BisGMA/40%HEMA (peso) +0,2% DMPA 1 (fotoiniciador) + 0,5% BHT(inbidor) - (BH-controle) foi formulada; o oligômero de TU PETMP-DEMODUR (tetrafuncional) foi sintetizado e adicionado em 20%(peso) à matriz orgânica dos grupos contendo TU (BH+ 20%TU); para os grupos contendo partículas de carga, estas foram funcionalizadas com metacrilato-MF ou com tiouretano-TF e adicionadas em 10%(vol). Os grupos experimentais foram: BH; BH+10%MF; BH+10%TF; BH+20%TU+10%MF; BH+20%TU+10%TF; BH+20%TU. Os grupos foram submetidos aos testes: resistência de união à microtração (RUMT) em 24 h e 6 meses em dentina hígida (n=6); resistência à flexão (RF) por três pontos em ambiente seco (n=6) e armazenadas em água por 7 dias (n=6); Cinética de polimerização (n=3) (grau de conversão-GC e taxa máxima de polimerização-Rpmax); Sorção e Solubilidade (SR/SL) (n=3); e, Viscosidade (V)(n=3). Para a RUMT, foi adicionado 40% etanol(vol) aos grupos experimentais. Os dados foram submetidos a ANOVA um fator e teste de Tukey (p0,5) e RF a seco (p>0,05), não houve diferença significativa entre os grupos. Os grupos contendo TU na matriz apresentaram os menores valores de RF (p0.05). For the comparison of storage time for the microtensile bond strength test, data were submitted to t test (p>0.05). For the microtensile bond strength test (p=0.13) and WS/SL (p>0.05), no significant difference was found between groups. For the YS and YM (p>0.05), the dry evaluation had no significant difference in YS, although for the YM BH+10%MF, BH+10%TF and BH+20%TU+10%MF had the highest values compared to BH, BH+20%TU+10%TF and BH+20%TU and in the wet evaluation, the groups containing TU in the matrix had the lowest values in YS and YM. The polymerization kinects for the groups containing TU in the matrix had the highest DC and no significant difference was found between groups for the DC at Rpmax. The Rpmax was higher for the BH+20%TU+10%MF, followed by BH and BH+10%TF, and the lowest Rpmax values were found for the BH+10%MF, BH+20%TU+10%TF and BH+20%TU. The groups containing TU in the matrix had the highest values for viscosity, being that the BH+20%TU+10%TF that has TU in the matrix and on the functionalized fillers had the highest values with statistical significant difference for the BH+20%TU+10%MF and BH+20%TU. The addition of TU in the matrix improved the final degree of conversion of the experimental adhesives and the bond strength maintained stable after 6 months of storage in water. With that, the addition of TU in the matrix of experimental adhesives improved the final Degree of conversion is a promising strategyDoutoradoMateriais DentariosDoutora em Materiais Dentários0878/2018CAPE

Influence of chemical degradation and abrasion on surface properties of nanorestorative materials

Aim: The aim of this in vitro study was to investigate the synergistic effect of chemical degradation (erosion) and three-body abrasion (mechanical degradation) on the surface roughness (Ra) and hardness (KHN) of two nanorestorative materials and two conventional materials. Methods: Discshaped specimens (5 mm in diameter, 2 mm thick) of Filtek Z350™ and TPH Spectrum™ composites and Ketac Nano™ and Vitremer™ light-curing glass ionomer cements, nanomaterials and conventional materials were prepared according to the manufacturer's instructions. After 24 h, polishing procedures were performed and initial measurements of Ra and KHN were taken in all specimens. The specimens were divided into 12 groups (n = 10) according to material and storage media: artificial saliva, orange juice, and Coca-Cola®. After 30 days of storage, the specimens were submitted to mechanical degradation and re-evaluated for Ra and KHN. Data were tested for significant differences by repeated-measure three-way ANOVA and Tukey's tests (p<0.05). Results: Erosion and abrasion wear significantly decreased hardness of all materials. Only Filtek Z350 roughness, however, was not affected by erosion and abrasion. All materials showed a significant increase in surface roughness after erosion and abrasion, except for Filtek Z350. After chemical and mechanical degradation, the KHN of all samples had decreased significantly. After mechanical degradation, the acidic drinks (Coca-Cola® and orange juice) were more aggressive than artificial saliva to all materials. Conclusions: A synergistic effect was observed by the increase in roughness for all materials, except for Filtek Z350; hardness values decrease for all materials, regardless of whether they were nanofilled or not. The RMGICs were more susceptible to degradation than the composites, considering both hardness and roughness surface parameters142100105sem informaçã

Avaliação do pré-tratamento de MI Paste™ e diferentes sistemas adesivos na µTBS da dentina desmineralizada.

O objetivo do presente estudo foi avaliar o efeito de MI Paste™ e dois sistemas adesivos (Adper™ Single Bond 2-SB e Clearfil™ SE Bond-CSE) na resistência de união à microtração (µTBS) da dentina desmineralizada. 36 blocos de dentina média obtidos foram distribuídos em 6 grupos (n=6): G1 - Dentina Hígida/SB - DH/SB; G2 - DH/CSE - DH/CSE; G3–DentinaDesmineralizada/SB - DD/SB; G4–DD/CSE; G5-DD+MI Paste™-MP/SB - DD+MP/SB; e G6–DD+MP/CSE. Blocos de compósito FiltekTM Z350XT (4mm) foram construídos sobre a dentina com SB ou CSE e os conjuntos armazenados por 24h a 37ºC em água destilada. Palitos (1mm ­ área de secção) foram obtidos e submetidos ao teste de μTBS (1,0mm/min ­ 500N). Os dados de μTBS (MPa) foram submetidos à ANOVA e teste de Tukey, e Dunnett (α=5%). Os tipos de fraturas foram avaliados por MEV. Houve interação significativa dos dados de μTBS, entre os fatores (Adesivo/Substrato) (

Surfactin application for a short period (10/20 s) increases the surface wettability of sound dentin

International audienceThe aim of this study was to evaluate the effect of spreading the lipopeptide surfactin, for short time (10/20 s), on dentin wettability. Study groups were surfactin: 2.8; 1.4; 0.7; 0.35; and 0.175 mg/mL and a control group that received no treatment. Dentin discs (4 mm height) were prepared and polished with 600-grit SiC paper. Contact angle determinations were carried out after microbrush spreading of surfactin on dentin specimens for, respectively, 10 and 20 s. Excess liquid was removed, and after 60 s, the specimens were analyzed in a goniometer using the sessile drop method to measure the contact angle. Results were analyzed by two-way ANOVA (concentration x time) and t student, with alpha = 0.05. Lower contact angles were obtained for surfactin (0.7 mg/mL) spread for 10 s. However, no statistical difference was observed for surfactin (2.8 mg/mL) applied during 20 s. Higher contact angles were observed for surfactin (0.7 mg/mL) spread for 20 s. In conclusion, dentin wettability is dependent on spreading time and surfactin concentration

Dentin growth factors release in regenerative endodontic procedures: a systematic review

Background: Regenerative endodontic procedures are promising alternatives for pulp regeneration. A better understanding of which specific agents can decontaminate root canal systems and increase the presence of growth factors into the canal can help in decision making for regenerative endodontic treatments. Types of Studies Reviewed: Studies that investigated growth factors release associated with different irrigating solutions or intracanal medications in human dentin will be included to assess substances are more effective in releasing dentin growth factors, essential for tissue regeneration process. The GRADE tool will be used to assess studies’ methodological quality. Sources: PubMed, Web of Science, Scopus, Google Scholar databases and gray literature, considering studies in English (2015-2023)

Influence of chemical degradation and abrasion on surface properties of nanorestorative materials

e aim of this in vitro study was to investigate the synergistic effect of chemical degradation (erosion) and three-body abrasion (mechanical degradation) on the surface roughness (Ra) and hardness (KHN) of two nanorestorative materials and two conventional materials. Methods: Discshaped specimens (5 mm in diameter, 2 mm thick) of Filtek Z350TM and TPH SpectrumTM composites and Ketac NanoTM and VitremerTM light-curing glass ionomer cements, nanomaterials and conventional materials were prepared according to the manufacturers instructions. After 24 h, polishing procedures were performed and initial measurements of Ra and KHN were taken in all specimens. The specimens were divided into 12 groups (n = 10) according to material and storage media: artificial saliva, orange juice, and Coca-Cola®. After 30 days of storage, the specimens were submitted to mechanical degradation and re-evaluated for Ra and KHN. Data were tested for significant differences by repeated-measure three-way ANOVA and Tukeys tests (p<0.05). Results: Erosion and abrasion wear significantly decreased hardness of all materials. Only Filtek Z350 roughness, however, was not affected by erosion and abrasion. All materials showed a significant increase in surface roughness after erosion and abrasion, except for Filtek Z350. After chemical and mechanical degradation, the KHN of all samples had decreased significantly. After mechanical degradation, the acidic drinks (Coca-Cola® and orange juice) were more aggressive than artificial saliva to all materials. Conclusions: A synergistic effect was observed by the increase in roughness for all materials, except for Filtek Z350; hardness values decrease for all materials, regardless of whether they were nanofilled or not. The RMGICs were more susceptible to degradation than the composites, considering both hardness and roughness surface parameters

O uso do gel de glicerina melhora a estabilidade de cor de resinas compostas?

Resumo Introdução A camada superficial de resina composta não polimerizada, em função da presença do oxigênio, ocasiona problemas clínicos, como alteração de cor por absorção de pigmentos. Objetivo Determinar o efeito de diferentes técnicas usadas no controle da formação da camada de dispersão sobre as propriedades ópticas de uma resina composta comercial. Material e método Espécimes foram produzidos com a resina composta Estelite Sigma. A fotoativação foi conduzida com uma fonte de luz LED Bluephase G2 (1.200 mW/cm2 por 40 s). Os grupos foram determinados em função de três técnicas distintas: 1) sem tratamento (controle); 2) fotoativação com gel de glicerina; 3) polimento com lixa abrasiva após a fotoativação. A estabilidade de cor (ΔE) e o parâmetro de translucidez foram determinados pelo método de espectroscopia de reflectância (Easyshade Compac, Vita) empregando o parâmetro CIELab. As análises foram realizadas imediatamente após a fotoativação e repetidas após 7 dias de armazenamento em água ou em café. Os resultados foram submetidos à análise de variância e ao teste de Tukey (α = 0,05). Resultado Não houve diferença para ΔE nos grupos envelhecidos em água. Quando armazenados em café, o grupo controle apresentou o maior valor de ΔE, enquanto o grupo polido gerou a menor alteração de cor. A aplicação do gel de glicerina produziu resultados intermediários. O parâmetro de translucidez não foi afetado pelos tratamentos testados. Conclusão O uso do gel de glicerina minimiza a alteração de cor nas regiões de difícil acesso aos instrumentos de acabamento e de polimento

Enhancing bond strength on demineralized dentin by pre-treatment with selective remineralising agents

Bonding to demineralized dentin of a diseased tooth has shown to be a significant clinical issue. This study evaluated the effect of 0.2% NaF-(NaF), MI Paste™-(CPP-ACP) and the self-assembling peptide ‘P 11 − 4 ′ (Ace-QQRFEWEFEQQ-NH 2 ) contained in Curodont™ Repair, have on microtensile bond strength-(µTBS) of two different adhesive systems (Adper™ Single Bond-(SB) or Clearfil™ SE Bond (CSE)) and wettability of demineralized dentin slices after remineralising agents were applied. The highest µTBS were found for the demineralized dentin-(DD) treated with CPP-ACP; both adhesives systems (p 0.05). The NaF treatment associated with CSE recovered the bond strength values of SD/CSE and associated with CSE demonstrated lower µTBS than other groups, although significantly higher than DD (p 0.05). Morphological analysis of the dentin surface and dentin-resin interface revealed unique features of the applied remineralizing agent. The results indicated that self-assembling peptide P 11 − 4 associated with SB and CPP-ACP associated with SB or CSE significantly enhanced the bond strength to demineralized dentin (p < 0.05). We conclude that by modifying the dentine surface and restoring conditions found on sound dentin, this can enhance the interfacial bonding